Note: Descriptions are shown in the official language in which they were submitted.
~2;~ 93~ D-13858-(:
-- 1 --
TITLE OF THE INVENTION
HIGH MOLECULAR WEIGHT
WATER- SOLUBLE POLYMERS AND FLOCCULATION
METHOD 13SING SAME
-
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to water-soluble acrylamide containing
polymers and their use in, for example, flocculation of waste
mineral processing streams.
Descripticn of the Prior Art
In a number of mining industries such as copper, iron
(taconite), ptash, phosphate, coal, etc., waste products
from the ore processing present serious disposal problems.
For example, in the phosphate mining industry, processing
leads ~o about one-third recoverable phosphate rock~, about
one-third sand tailings and about one-third fines of
generally less than 150 mesh particle size. Aqueous
D-13858 C
~ 3
-- 2 --
suspensions of these ultrafine solids, which are
associated with the ore, and which result from the
processin~, are referred to as ~slimes.U In the central
area of t}le State of Fl-orida, where a large portion of the
U.S. phosphate mining industry exists, the problem of
~isposal of these slimes has become a major problem. The
slimes may be contained in ponds cr impounded areas
surrounded by earthen dams and allowed to settle by
gravity. However, this process takes a number of years.
lQ Alternatively, flocculants may be employed to concentrate
the suspended solids.
Similarly, in the coal mining industry, large amounts of
so-called ~blackwater~ are generated as a waste product of
the coal cleaning plant operations. Such blackwater
contains suspended coal fines and clays which desirably
are removed prior to disposal or reuse o~ the water.
Mineral sli~es exhibit colloid-like properties that are
believed to be largely responsible for their poor
dewatering characteristics and generally comprise very
fine colloid-like particles (e.g., clays) suspended in
water which, in the case of phosphate slimes, are largely
Montmorillonite and Attapulgite clays. Attapulgite and
Montmorillonite clays together are known to comprise
approximately one-third of a typical phosphate slime.
These clay materials are also well knoun for their
colloid-like behavior when exposed to water~ They tend to
absorb water or to associate with water and orm a
~uspended material which may be difficult to flocculate.
~ater-~oluble acrylamide polymers and copolymers are known
as being useful for the flocoulation o~ such phosphate
$1imes and blackwater ~u~pensions. ~or example,
U. S. Patent No. 4,529,782 ~cribe6 ~ de-contain~
~f,'' .
~-13,858
:
.... . .
~L2257~3
-- 3 --
polymers, having an intrinsic YiScosity of at least 15
dl/g, useful for flocc~lating phosphate slimes. ~he
disclosed polymers may ~e terpolymers which may be
represented by the following formula:
t H~ - C ~tC~2 - ~ ~CH2 - ~
NH2 0~
- R2~ d
wherein R, Rl and R3 are independently hydroge~ or
met~yl: R2 is an alkali metal ion, such as Na+ or K+ :
R4 is OR5, where R5 is an alkyl group having up to 5
carbon atoms,
O O
Il 11
-O-C-R7, where R7 is eit~r methyl or ethyl, -C-O-R6,
pnenyl, substituted phenyl, CN, or ~
and R6 is an alkyl group having up to 8 carbon atoms;
wherein a is from about 5 to about 90 mole percent, b is
rom 5 to about g0 mole percent, c is from about 0.2 to
about 20 mole percent, a~d d is an integer of from about
100,000 to about 500,000.
An example of such a terpDlymer is one derived ~rom a
monomer mixture comprising about 54.3 mole percent
acrylamide, about 4.6 mole ~ vinyl acetate and about 41.1
mole % sodium ~crylate.
Also disclo~ed in said ~x~e~d~ng U. S. Patent No. 4,529,782 are
tetrapolymers obtained by the partial hydrolysis of ~he
R~ group in the above ~ormul~.
,.
.~L~ D-13~858
~;2S793
A process ~or flocculatin~
pho~phate slimes employing employing such polymers is dis-
cioce-d in IJ.S. Patent No. 4,555,346- The disclosed process
generally comprises MiXing a dilute aqueous solution of
the polymer with the phosphate slimes under appropriate
floc-forming conditions and allowing the suspended solids
to settle from the slime to form an underflow of a more
concentrated suspension of the clay solids and an
essentially clear aqueous supernatant liquid.
Japanese Patent Publication No. 51-18913 describes a
method of accelerating the aggregation/filtration of a
fine mineral particle suspension using water-soluble
terpolymers. These polymers are described as having a
molecular weight above 1,000,000, preferably above
3,000,000, and comprise 5-50 weight % of a univalent salt
of acrylic or methacrylic acid, 40-90 weight % of
acrylamide, methacrylamide or methylol derivatives
thereof, and 1-50 weight ~ of a weakly hyd~ophilic vinyl
monomer. Table 1 therein describes a terpolymer prepared
from 25 weight % sodium acrylate, 55 weight ~ acrylamide
and 20 weight ~ vinyl ac2tate having a molecular weiyht of
1,500,000. GerMan Offenlegungsschrift No. 2,543,135
discloses similar polym~rs as flocculants.
Copolymers of about 75 weight 4 acrylamide and about 25
weight ~ sodium a~rylate are also known to be useful ~s
flocculants in various aqueous ~ystems. U.S. Patent Nos.
3,790,476, 3,790,477, 3,479,282 and 3,479,284 disolose
~imilar ~crylamide/sodium acrylate copolymers and state
tha~ they are useful as flocculants.
U.S. Patent ~o. ~,342,653 discloses a process for
~locculating ~ueous ~olid di~persions, ~uch as phosphate
D-13,858 .
... ~,;~ .
i~ .' 1 1
... .. . ,~ .. . . .. ... ..
. . .
~225793
-- 5 --
slimes, with polymeric anionic flocculants comprising
40-99 mole % of repeating units derived from acrylamide,
1-35 mole % of repeating units derived from 2-acrylamido-2-
methylpropane sulfonic acid (which is available from the
Lubrizol Corporation under its product designation and here~te2
referred to as, ~AMPS"~ and 0-25 mole ~ of repeating units
derived from acrylic acid.
U.S. Patent no. 3,692,673 discloses water-soluble
sulfonate polymers said to be useful as flocculants for
aqueous systems, especially in combination with inorganic
co-flocculants. The polymers contain units of the formula:
R
- CH2-- I
C ", o
NH
I
R - (S03M)x
wherein ~1 is hydrogen or lower alkyl which may be
substituted; R2 is a divalent or trivalent hydrocarbon
or substituted hydrocarbon radical M is a hydrogen atom
or one equivalent of a cation: and x is 1 or 2. The
polymers may be obtained by polymerizing, either alone or
in combination with other polymerizable vinyl monomers, a
corresponding monomeric N-sulfohydrocarbon- subsSituted
acrylamide (e.g. "A~IPSR or its alkali metal or ammonium
6alt). It is further disclosed that the most useful
polymers are homopolymers of such monomers and copolymers
thereof with 5-95 weight ~ of ~n acrylic monomer such as
~crylic or methacrylic ~cid or a salt or amide thereof
(e.g., acrylamide). specific disclosed copolymers are 80
weight S sodium "AMPS/20 weight ~ ~odium ~crylate and 95
weight ~ sodium ~AMPS~/5 weight % ~crylamide.
Pi~ ~ D-13,858
,. . ~
S~93
-- 6
U.S. Patent No. 3,709,815 discloses copolymers of ~AMPS~
with acrylamide or acrylic acid as flocculants for aqueous
systems. U~S. Patent No. 3,709,816 discloses flocculating
alluvial deposits (e.g., silt) in water systems with
"AMPS" or sodium ~AMPS~ water-soluble polymers, which may
be "AMPS~ homopolymers or ~A~IPSn copolymers (containing at
least 2 mole ~ "AMPS") with other comonomers, preferably
acrylamide, acrylic acid, vinyl acetate, methyl acrylate
or styrene. Other water-soluble monoethylenically
unsaturated monomers which may be used include the alkali
metal salts of acrylic and methacrylic acids, etc.
U.S. Patent ~lo. 3,975,496 discloses water-soluble
copolymers useful as flocculants, especially in settling
red mud obtained by the digestion of bauxite. The
copolymers are, for example, acrylamide copolymers with
either ~AMPS" or sodium acrylate wherein the acrylamide is
partially methylolated.
Conversely, U.S. Patent Nos. 3,898,037 and 3,806,367
disclose acrylamido-sulfonic acid copolymers useful as
dispersants or deflocculants for particles in aqueous
systems. The copolymers (which have a molecular weight of
750 to 5,000,000) may comprise "AMPS" (or a salt thereof)
copolymerized with a vinyl monomer, such as acrylic acid,
esters thareof, acrylamide, vinyl acetate, etc.
Japanese Patent Publication No. 53-55488 discloses a
flocculant comprising a water-soluble polymer containing
about 90-99.8 mole ~ of an amide-type vinyl unit (e.~.,
acrylamide), about 0.1-5 mole % of a sulfonic group-
containing vinyl unit (e.g., ~AMPS~ or its salt) and 0.1-5
~ole % of a carboxyl group - containing vinyl unit (e.g.,
acrylic acid or its salt). The disclosed polymer is said
to be useful for the sedimentation of used and waste
water, for concentration, and for dehydration of various
types of dirt.
D-13,858
~Z;25793
-- 7 --
Japanese Patent Publication No. 52-37580 discloses a
method of aggregating solids suspendeZ in aqueous media
employing an aggregating agent which comprises a copolymer
which exhibits a strong tendency to form threads and which
is obtained by polymerizing a mixture of 65-98 weight % of
acrylamide and 2-35 weight % "AMPS~, where the total mono-
mer concentration in the mixture is at least 15 weight ~.
Japanese Patent Publication No. 54-61285 discloses a
method for preparing a polymeric aggregating agent wherein
the wet polymer is heated at a temperature above the
copolymerization temperature and then dehydrated and
dried. The polymer is a copolymer containing 55-98 weight
% of acrylamide and 2-45 weight % "AMPS" (or its salt) and
optionally, up to 20 weight % of a thir~ copolymerizable
monomer (e.g., sodium acrylate).
British Patent No. 1,437,281 discloses high molecular
weight, water-soluble acrylamide polymers useful as
flocculating agents for, e.g., mineral processing slimes.
The polymer comprises a~ least 50 weight % of acrylamide,
0-50 weight % of acrylic acid or its alkali metal salt and
up to 5 weight % of other ethylenically unsaturated
monor,~ers such as ~AMPS~ or its alkali metal salts.
British Patent No. 1,401,353 discloses the use of ~AMPSn -
containing polymers as retention and drainage aids in
paper manufacturing. The polymer contains at least 2.5
mole % ~AMPS" (or its salt) and 0-97.5 mole % o~ a
comonomer such as acrylamide or sodium acrylate and,
optionally, up to 20 mole % of other water-soluble
comonomers and up to 10 mole % of water-insoluble
comonomers.
U.S. Patent No. 4,024,040 discloses a radiation process
for preparing water-soluble, high molecular weight
D-13,858
~2;~ 93
acrylamide polymers useful as flocculating agents. The
polymer is prepared from an acrylamide-type monomer, or
mixtures thereof, which monomer may be acrylamide, an
alkali metal acrylate, 2-acrylamido-2-methylpropane-
sulfonic acid ("AMPSn) or its salt, etc. No specific
~AMPSn - containing polymers are disclosed.
~est German Published (Non-Prosecuted) Application No.
1,442,408 discloses a flocculating a~ent comprising a
copolymer of acrylamide and l to 10 ~ of compounds of the
formula
Il .
CH2 = C - C N - (C~12)n -Y
l l
Rl R2
wherein Rl is hydrogen or methyl, ~2 is hydrogen or
Cl 4 alkyl, Y is SO3X or O-SO3X, X is a monovalent
cation such an alkali metal, and n is a whole number such
as 2 or 3.
It has now been found that improved flocculation efficiency
is obtained in aqueous systems such as phosphate slimes
and coal blackwater when the water-soluble acrylamide
polymers of the present invention are used as flocculants.
SUMMARY OF THF INVENTION
Broadly stated, the present invention comprises water-
soluble acrylamide-containing polymers , water-in-oil
emulsions of such polymers and the use of such polymers in
flocculating aqueous solid suspensions such as phosphate
slimes and blackwater derived from coal washing. The
polymers of the invention may be represented by the
D-13,858
~Z257g3
following formula:
~m ~C~2 ~ C ~ f C~2 c~----~B~--
C=O C=O
. R~ N \ _ r
SO3X
wherein A represents a repeating unit derived ~rom a
hydrophobic vinyl monomer having a water-solubility of
less than about 5 weight ~; Rl and R3 are each a
hydrogen atom or a methyl group; R4 and R5 are each a
hydrogen atom, a r.lethyl group or an ethyl group; R2
represents a divalent hydrocarbon group having from 2 to
13 carbon atoms; X represents a monovalent cation; B
represents a repeating unit derived from an
ethylenically-unsaturated carboxylic acid or a salt
thereof; m is about 0.1 - 10 mole %, n is about 1-40 mole
%, p is about 2G-98.9 mole ~, and q is about 0-40 mole %,
with the proviso that m + n + p + q = 100 mole %; and r is
a large positive integer. Alternatively, the polymer may
be defined as that resulting from the polymerization of a
water-in-oil monomer emulsion containing r,lonomers
corresponding~to the repeating units in the above formula
in amounts of about 0.1-20 mole ~ of monomer ~A", about
1-40 mole ~ of the S03X-containing
R3 R4
11
monomer, about 20-98.9 mole % of monomer CH2 = C - C - N - Rs
and about 0-40 mole % of monomer "Bn, all based on the
total moles of mGnomer in the emulsion.
D-13,858
"
~257~3~
-- 10 ~
The present invention also resides in a process for
flocculatin~ an a~ueous solid suspension which comprises
mixing the suspension with the above-identified polymer
under appropriate floc-forming conditions and allowing the
suspended solids to settle to form an underflow of a more
concentrated suspension of the solids and an essentially
clear aqueous supernatant liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1-3 sho~l the flocculation efficiency of terpolymers
of the invention and three other polymers in three
different phosphate slimes.
Figure ~ shows the flocculation efficiency of ~1) a sodium
"A~IPSn/acrylamide/vinyl acetate terpolymer, (2) a sodium
"AMPSn/acrylamide copolymer prepared by the dual-initiator
process and (3) a prior art sodium "AMPS~/acrylamide
copolymer, in a phosphate ~lime.
Figure 5 shows the flocculation efficiency, in a phosphate
slime, of a sodium "AMPSn/acrylamide/vinyl acetate
terpolymer and a sodium ~AMPSn/acrylamide copolymer
prepared by the dual-initiator process.
Figure 6 compares the flocculation efficiency, in a
phosphate slime, of three sodium "AMPSn/acrylamide~
vinyl acetate terpolymers (having differen~ vinyl acetate
contents and a sodium "AMPSn/acrylamide copolymer prepared
by the dual-initiator process.
Figure 7 shows the effect of the content of vinyl acetate,
in various polymers, on flocculation efficiency.
D-13,858
~25t793
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As is apparent from the foregoing summary, the polymers of
the present invention may be terpolymers (when q is zero)
or tetrapolymers. Both types of polymers are useful in
flocculating aqueous solid suspensions and the selection
of which type, and of the particular monomers in each
polymer, will vary depending upon, for example, the
specific suspension being flocculated, economic
considerations te.g., the cost of particular monomers),
the desired rate of settling, and the desired degree of
solids compaction, etc. These and other considerations
will be fully discussed below so as to enable those
skilled in the art to practice the present invention.
Vue to the fact that the polymers of the invention are
often of very high molecular weight, it may be difficult
to determine the precise content of the hydrophobic monomer
unit "A~ in the polymer althoush there generally is no
such difficulty in ascertaining the content, in the
polymer, of the other monomer units. However, based on
the known reactivity of a given hydropho~ic monomer "A~,
the reactivities of the other monomers, the amount of all
monomers present in the monomer emulsion to be polymerized
and the polymerization conditions, the order of magnitude
of the content of the hydrophobic monomer unit ~A~ in the
resulting polyrner may be determined. For example, for a
pre~erred terpolymer of the invention derived by polymeri-
zing a water-in-oil monomer emulsion containing 8-12 mole
% of sodium ~AMPS" monomer, 87-91 mole % of acrylamide
monomer and about 1 mole % of vinyl acetate monomer, it is
expected that the resulting polymer would contain a
minimum of about 0.2-0.25 mole %, and probably close to
that level, of total vinyl acetate (including unhydrolyzed
and hydrolyzed vinyl acetate moieties). Therefore, the
polymers of the invention may be described either in terms
of the
D-13,858
- 12 -
monomer content of the water-in-oil monomer emulsion
polymerized to form such polymer, or in terms of the
repeating unit contents of the polymer.
The polymers of the invention may be random or block
copolymers although it is expected that they have both
sections of random copolymer structure as well as other
sections of block structure. It is not the purpose to
limit the`present invention to any particular type of
structure.
The terpolymers of the present invention may be
represented by the following formula:
~ ~t- ~ C~2 - C ~ , ~ C~2 ~ C - -
C=O C=O
~3 R4 ~ R5 r
S03X
wherein:
(1) ~' represents a repeating unit derived from a
hydrophobic vinyl monomer having a water-solubility of
less than about S weight percent, such as those monomeric
repeating units represented by the formula:
R6
CH2 C
R7
O O
Il 11
wherein R6 is -H or -CH3: R7 is - C - 0 - R8, - O - C - Rg,
a halogen atom (e.g., chlorine), - 0 - Rlo or ~ Rll,
D-13,85B
~5~793
- 13 -
where R8 is an alkyl group having from 1 to 12 carbon
atoms, preferably 1 to 4 carbon atoms, most preferably a
butyl group, R9 is an alkyl ~roup having from 1 to 4
carbon atoms, preferably a methyl group, Rlo is an alkyl
group having from 1 to 6 carbon atoms, preferably from 2
to 4 car~on atoms, Rll is a hydrogen atom, a methyl
group or an ethyl group, preferably a hydrogen atom or a
methyl group. Examples of pre~erred hydrophobic vinyl
monomers include vinyl acetate, styrene, alpha-methyl
styrene, ethyl acrylate, methyl acrylate, ethyl
methacrylate, methyl methacrylate, butyl acrylate,
isobutyl acrylate, dodecyl acrylate, 2-ethylhexyl
acrylate, vinyl propionate, vinyl butyrate, propyl vinyl
ether, butyl vinyl ether, methyl vinyl ether, ethyl vinyl
ether, isobutyl vinyl ether, vinyl chloride, and
vinylidene chloride.
(2) Rl and R3 are each a hydrogen ator,l or a ~ethyl
group although it is preferred that both Rl and R3 are
hydrogen atoms;
(3) R2 is a divaler.t hydrocarbon group having from 2 to
13 carbon atoms, such as alkylene yroups having from 2 to
8 carbon atoms, cycloalkylene groups having from 6 to 8
car~on atoms, phenylene, and the like. Preferred divalent
hydrocarbon groups include -C(CH3)2-CH2-, -CH2CH2-,
-~n2~n2~n2 , ~n2~n2~n2 2
CH3
~ , CH CH2 , ~
and ~ C - . The most preferred R2 grouping
I
CH3
is -C(CH3)2-CH2- which forms sodium ~lPS~ when Rl =
hydrogen and X is sodium;
D-13,858
S793
- 14 -
(4) X is a monovalent cation such as a hydrogen atom, an
ammonium group, an al~ali metal atom (e.g., Na or K), or
an organoammonium group of the formula
15 16)( 17)NH+ where R15, R16 and R17 are
each a hydrogen atom, an alkyl group having from 1 to 3
carbon atomsJ or a hydroxyalkyl group having from 1 to 3
carbon atoms, and the like. The pre~erred cation is a
sodium atom.
(5) R4 and R5 are each a hydrogen atom, a methyl group
or an ethyl group although it is preferred that both R4
and R5 are hydrogen atoms;
(6) m i5 about 0.1 - 10 mole ~, pre~erably about 0.2-5
mole %;
(7) n is about 1-40 mole %, preferably about 5-20 mole
~;
(8) p is about 50-98.~ mole %, preferably about 75-95
mole ~;
(9) m ~ n + p = 100 mole %; and
(10) r is a large positive integer, such as from about
1,000 to about 200,000. Generally, it is preferred that
the polymer be a high molecular ~eight, linear polymer
since both characteristics tend to favor improved
flocculation. Due to the high reactivities of the
monomers represented by the n and p moieties in the above
formulaJ especially sodium ~AMPS~ and acrylamide, the
formation of very high molecular weight, linear polymers
may be readily accomplished. The molecular weight of the
terpolymer (as well as the tetrapolymer) of the invention
is generally greater than about 500,000 and preferably is
greater than about 1,000~000.
D-13,858
~L~2~i7gl3
- 15 -
Some of the acetoxy or alkoxy groups of R7 (i~e., the
o
- O - C - Rg, or - O - Rlo groups, respectively) may
be hydrolyzed, resulting in a tetrapolymer which may be
represented by the formula:
~ CH2--C t ~CH2 c ~ ~H2 C t ~CH2 c--t~
R7 m-z OH z C=O n C=O p
NH R4R5 r
_ R2
S03X
where~n Rl ~ R2 l R3 ~ R4 ~ R5~ R6~ 7~ ,
n , p and r are as defined above, and z is from
about 0.1 to less than about 10 mole ~ and wherein
(m' - z') + z' ~ n' + p' = 100 r,lole ~.
Alternatively, instead of defining the terpolymer
repeating units as in (6) - (8) above, the terpolymer (and
its hydrolyzed derivative) may be defined as that
resulting from the polymerization of a water-in-oil
monomer emulsion containing from about 0.1-20 mole %,
preferably 0.2-10 mole ~ of Jnonomer A', about 1-40 mole %~
preferably about 5-20 mole ~, of the S03X-containing
monomer, and about 50-98.9 mole ~,
R3 l~ R4
preferably about 75-95 mole %, of monomer CH2 ~ C - C - N - Rs,
all ba~ed on the total moles of monomer in the emuleion.
D-13,858
. ~, ..
. ~ ,,
~2;~5793
- 16 -
Examples of suitable S03X-containing monomers are "AMPS"
sodium "AMPSn, and the like~ The most preferred monomer
is sodium "AMPS~.
. R3 R4
Examples of suitable monomers of the formula CH2 = C - C - N - R~
are acrylamide, methacrylamide, dimethylacrylamide, and
the like. The most preferred monomer of this type is
acrylamide.
0
The most preferred terpolymer is that resulting from the
polymerization of a water-in-oil monomer emulsion
containing about 8-12 mole % of sodium "A~IPS" monomer,
about 87-91 mole % of acrylamide monomer and about 1-5
mole % of vinyl acetate monomer. Such terpolymers are
especially useful in flocculating phosphate slimes.
The tetrapolymers of the present invention may be
represented by the following formula:
A'-~ ~C32 - C ~ 3
L NH R ~ R5 ~rn
R2
_ I
S03X
' l' R2l R3, R4 and R5 have the same
meaning as defined above with respect to the terpolymer of
the invention; wherein m , n , and r have the same
meaning as m , n and r , respectively, defined
above with respect to the terpolymer of the invention; and
wherein
D-13,858
~ ~5~3
~ 17 -
(1) p is ~bout 20-98.9 mole ~, preferably abo~t
40-86.9 mole ~;
. .
(2) q is greater than 0 and up to 40 mole ~,
preferably about 10-30 mole %;
(3) B represents a repeating unit derived from an
ethylenically-unsaturated monomer containing a carboxylic
acid group such as acrylic acid, methacrylic acid, maleic
acid, and the like and salts thereof with alkali metals
(e.g., sodium, potassium, etc.) , ammonia (i.e., ammonium
salts) and organic amines ~e.g., amines represented by the
tR12)(R13)tR14)N- wherein R12, R13 and
R14 are each a hydrogen atom, an alkyl ~roup having from
1 to 3 carbon ato~s, or a hydroxyalkyl group having from 1
to 3 carbon atoms such as trimethylamine, triethanolamine,
etc.). Examples of suitable monomers include acrylic
acid, methacrylic acid, maleic acid, sodium acrylate,
ammonium acrylate, tri~ethylammonium acrylate, and the
like. The preferred B monomer is sodium acrylate.
Some of the alkoxy or acetoxy groups of the hydrophobic
monomer A' may be hydrolyzed, resulting in~a pentapolymer
which may be represented by the formula: ~
~ } ~ I t { I t
R7 m-z OH z C~O n C-O p
NH ,N r
_ i' R2
S03X
~ a a
where~n Rl~ R2~ R3~ R4~ R5~ R6~ 7~
and r are as defined ~bove, and z is from ~bout 0.1 to
less than ~bout 10 ~ole ~;
~, ; D-13,858
. . . ... .... . . . .
~2~ 3
- 18 -
Alternatively, instead of defining the tetrapolymer
repeatin~ units as above, the tetrapolymer (and its
hydrolyzed derivative~ may be defined as that resulting
from the polymerization of a water-in-oil monomer emulsion
containing about 0.1-20 mole %~ preferably 0.2-lO mole 4
of monomer A', about 1-40 mole %, preferably abut 5-20
mole ~, of the So3X-containing monomer, about 20-98.9
mole %, preferably about 40-86.9
R3 0 R4
1 ll I
mole %, of monorner CH2 = C - C - N - R5, and greater
than 0 to abo~t 40 mole %, preferably about 10-30 mole ~,
of monomer ~B~, all based on the total moles of ~onomer in
the er,lulsion.
The most preferred tetra~olymer of the invention is that
resulting from the polymerization of a water-in-oil
monomer emulsion containing about 6-lO mole % of sodium
~AMPSR monomer, about 50-70 mole % of acrylamide monomer,
about l-5 mole ~ of vinyl acetate monomer and about 20-40
mole ~ of sodium acrylate monomer. Such t~trapolymers are
especially useful in the flocculation of coal fines (e.g.,
blackwater).
The amounts of the sulfonic acid/sulfonate monomer and the
oarboxylic acid/carboxylate monomer may be varied
depending upon a number of factors. For example, an
~AMPS~ monomer is relatively more expensive than the
carboxylic acid/carboxylate monomerO since the presence
3~ of both a strongly acidic group ~i.e., the sul~onic
acid/sulfonate group) and a weak acid (i.e., the
carboxylic acid/~arboxylate group) ~ay provide a
~locculant which ls more versatile for a broader range of
applicatlo~s, the relative amounts may be tailored for
particul~r ~ppli~a~ions ~nd therefore the tetrapolymers
may provide both improved performance and better economy.
, y
~ D-13,85~
.~
3L225~7~3
}g
The polymers of the present invention may be prepared
using conventional techniques known to those skilled in
the art, ~or example by standard water-in-oil emulsion
polymerization processes. Such processes generally
comprise emulsifying one or more water-soluble monomers in
an oil phase and polymerizing the monomers in the
resulting emulsion. It is preferred that the polymers of
the invention be prepared as a w~ter-in-oil emulsion in
order to provide linear, high molecular weight polymers
which may nevertheless be recovered as solutions
containing high polymer concentrations. Ordinarily, such
polyrlers may best be prepared by water-in-oil emulsion
polymerization processes, such as the process disclosed in
U S. Patent No. 4,485,209.
The monorners polymerized to form the polymers of the
present invention are either commercially available or may
be prepared by processes known to those skilled in the
art. For example, the So3X-containing monomers may be
made by processes disclosed in U.S. Patent No. 3,506,707,
the disclosure of which is hereby expressly incorporated
herein by reference.
The water-in-oil emulsion polymerization process described
in U- S. Patent N- 4,485,209 . which may be used to prepare
the polymers of the present invention, comprises the steps
of:
(a) co~bining: (i) an aqueous ~hase con~prising an
~queous solution containing at least one water-soluble
monomer (i.e.~ the S03X-containing ~onomer, monomer
D-13,858
7 ' '
"~'.). '
. . . . - ' .
t~3
- 20 -
R3 R4
11 1
CH2 = C - C - N - R5 and monomer "B"~, and (ii) an oil
phase comprising a mixture of a hydrophobic liquid, a
hydrophobic monomer (i.e., monomer A or A') and an
oil-soluble surfactant;
(b) homogenizing the resulting mixture from (a) to form a
water-in-oil emulsion followed by deoxygenating the
emulsion;
(c) polymerizing the homogenized water-in-oil emulsion by
adding thereto a deoxygenated initiator solution and
heating the resulting mixture in a reactor under
polymerization conditions so as to form a polymer
water-in-oil emulsion; and
(d) recovering a polymer water-in-oil emulsion.
A water-soluble surfactant may be added to the recovered
water-in-oil emulsion to invert the emulsion on contact
with water.
In the first step of the process, an aqueous solution
containing one or more water-soluble monomers is combined
with a mixture containing a hydrophobic liquid, a
hydrophobic monomer and an oil-soluble surfactant. This
combination of materials is homogenized to form a
water-in~oil emulsion.
The ayueous solution contains a mixture of water-soluble
monomers represented by the formulas
D-13,858
- 21 -
Rl o
H2C = C ~ C - ~IH - ~2 - SO3X,
R3 o
1 ll ~ R4
H2C = C C - N ~5 and, optionally, B, where Rl,
R2, R3, R4, R5 X and B are as defined hereinabove. The
acids ~i.e., monomer ~B~ and the SO3X -oontaining
monomer) may first be reacted with a suitable base~
preferably with an equivalent amount of base, such as
sodium hydroxide, so that the resulting solution has a pH
of from about 5.0 tc about 10.0, preferably from a~out 6.5
to about 8.5, depending on the type and amount of base
esnployed. The resulting solution may then be co~bined
with another water-soluble monomer, such as acrylamide,
and then with water to form the aqueous solution used in
step (a).
The mixture which is combi~ed with the aqueous solution
containing the water-soluble monomers contains a hydro-
phobic liquid, a hydrophobic monomer (i.e., monomer A or
A' as defined above) and an oil-soluble surfactant.
The particular hydrophobic liquid is not critical.
Examples of suitable hydrophobic liquids for use herein
include benzene, xylene, toluene, mineral oils, kerosenest
petroleum, ~ixtures thereof, and the like. A preferred
hydrophobic liquid is an aliphatic hydrocarbon ~vailable
from the Exxon Chemical Co. under the tradename Isopar M.
The particular surfactant is not critical. Exa~ples of
~uitable ~urfactants are those of the oil-soluble type
having a Hydrophile-Lipophile Bal~nce (MLB) value of from
~bout 1 to about 10, preerably ~rom about 2 to abou~ 6.
~hese ~urfactants ~re normally re~erred to as the
water-in-oil type. The~e ~uitable ~urfactants lnc:Lude
D-13~858
- it~
~' ~ `'' i ,
... .. ~ ............ . . .
33
- 22 -
fatty acid esters, such as sorbitan monolaurate, sorbitan
monostearâte, sorbitan monooleate (such as that available
from I.C.I. under its tradename Spa ~80), sorbitan
trioleate, etc.; mono- and diglycerides, such as mono and
diglycerides obtained from the glycerolysis of edible
fats, polyoxyethylenated fa~ty acid esters, such as
polyoxyethylenated ~4) sorbitan monostearate;
polyoxyethylenated linear alcohols, such as Tergitol
15-S-3 and Tergito ~25-L-3 (both supplied by Union Carbide
Corp.); polyoxyethylene sorbitol esters, such as
polyoxyethylene sorbitol bees~-ax derivative;
polyoxyethylenated alcohols such as polyoxyethylenated (2)
cetyl ether, and the like.
The mixture of the aqueous phase and oil phase resulting
from step (a) is homogenized to form a water-in oil
emulsion. Homogenization takes place by subjecting the
mixture to high shear mixing techniques which are
generally well-kno~n in the art. These include the use of
homosenizers, hlgh speed mixers and any other techniques
for obtaining high shear mixin~. The homogenization is
carried out at a temperature of from about,0 to about
30C, preferably about 15 to 25C. The homogenization may
be carried out either continuously or in a batch process.
The emulsions so prepared have a rather narrow particle
size distribution. The diameters of the majority of the
particles range from about 0.2 to about 5 microns.
The resulting monomer water-in-oil emulsion comprises:
(a) from about 50 to about B0, preferably from about 60
to 78, weight percent, ~ased on the total weight of the
emulsion, of an squeous phase containing the water-soluble
monomers, wherein these monomers constitute ~rom about 20
to about 80, preferably from about 25 to about S0, weight
percent of the aqueous phase:
D-13,B58
~a2;~ii7~33
- 23 -
(b) from about lS to about 45, preferably from about 20
to about 40, weight percent, based on the total weight of
the emulsion, of an oil phase comprising the hydrophobic
liquid and hydrophobic monomer(s), wherein these monomers
S constitute from about 0.1 to about 20, pre~erably from
about 1 to 10, weight percent of the oil phase;
(c) from about 0.1 to about 5, preferably from about 1 to
about 3, weight percent, based on the total weight of the
emulsion, of the oil-soluble surfactant.
After forming the water-in-oil emulsion, either during or
after addition to a reactor, it is generally deoxygenated
by, for example, subjecting part or all of the emulsion to
a vacuum of from about 50 to about 500, preferably from
about 100 to about 200, mm of mercury under an inert gas
atmosphere at a temperature of from about 0 to about 30C,
either continuously or as a batch process.
A catalyst or initiator useful in polymerizing
ethylenically unsaturated monomers is also added to the
reactor. These catal~sts include azo-and peroxide-
containing compounds known in the art and are added to the
reactor either directly or in the form of a solution,
i.e., the catalyst is dissolved in a sGlvent, such as a
hydrocarbon liquid, e.g., toluene. The catalyst solution
contains from about 1 to about 10, preferably from about 3
to about 6, weight percent of the catalyst.
From about 1 to about 99, preferably from about 20 to
about 60, weight percent of the catalyst solution is
initially added to the reactor containing the water-in-oil
emulsion. The remaining water-in-oil emulsion and cata-
lyst solution are then continually fed into the reactor.
D-13,858
~L2;;~ 93
- 24 -
The polymerization is carried out at a temperature of from
about 30 to about 100C, preferably from about 40 to about
70C, mo$t preferably from about 45 to about 55C, for
about 1 to about 10 hours, preferably from about 2 to
about 6 hours. The reaction time depends on the size of
the reactor and the polymerization conditions.
Alternatively, all of the reactants may be charged into a
reactor and the polymerization conducted in a batch
operation.
The polymerization is generally carried out at atmospheric
pressure, although subatmospheric and superatmospheric
pressures may be used. The polymerization is preferably
carried out under an inert atmosphere, such as a helium,
argon or nitrogen atmosphere.
The polymerization reaction generates considerable heat
which must be removed. Generally, the heat is dissipated
by normal cooling facilities.
The polymerization reaction rate may be controlled by the
introduction of small quantities of air (atmospheric air
and/or oxysen) into the reaction. The air May be
introduced, i.e., sparged, either intermittently or
continuously into the reactor to control the reaction
temperature. ~hen a continuous air sparging is employed,
the amount of oxygen in the reaction mediuM must be
carefully controlled so as to achieve the desixed rate of
polymerization. An oxygen content of from about 0.01 to
about 1.0, preferably from about 0.02 to about O.S0, part
per million is desirable. When the air is introduced
intermittently, a flow rate of from about 0.01 to about
1.0, preferably from about 0.05 to about 0.5 cubic inches
D-13,858
93
- 24a -
per minute per pound of reactor charge is desirableO The
duration of air injection may vary from a fraction of a
second to a few seconds, and it may be repeated as many
times as necessary until a desired rate of polymerization
is achieved.
D-13,85~
~22~;~93
; 25 -
After the poly~erization is complete~ an antioxidant may
be added to the reaction mass. ~ny organic antioxidant
suitable for the inhibition of free radical reactions may
be used. The antioxidant is ~enerally dissolved in a
suitable solvent. The preferred antioxidants include
substituted phenols (such as tha~ available from Shell
Chemical Co. under its tradename Iono~ ~ thiobisPhenol
~such as is available from the Monsanto Chemical Co. under
its tradename santonox-lM-R~, and hydroquinone derivatives,
such as the monomethyl ether of hydroquinone. The
suitable solvents include toluene, benzene, xylene,
diethyl ether, methyl acetate, and the }ike. ~he
antioxidant is present in the solution in amounts of from
about 0.1 to about 10, preferably from about 1 to about 5,
weight percent.
The antioxi~ant solution is added to the reaction mass in
amounts of from about 0.05 to about 5 parts per hundred
parts of polymer. Addition of the antioxidant may be
commenced either at the end of the polymerization or after
the reaction mixture has been cooled to ambient
temperature.
The reaction mass is senerally cooled to about 25C and
the polymer water-in-oil emulsion recovered.
The resulting polymer water-in-oil emulsion generally
comprises:
(a) ~rom ~bcut 50 to about 80, preferably from about 60
to about 78, weight per~ent, based on the weight o~ the
entire emulsion, of an aqueous phase which oontains
therein from about 20 to about 80, preferably from about
25 to about 60, weiyht peroent of polymer, based on the
total wei~ht of the ~gueous phase;
~ 13,858
, ~ .
~2~7~3
- 26 -
(b) from about 15 to about 50, prefera~ly Irom about 20
to about 40 weight percent, based on the weight of the
entire emulsion, of a hydrophobic liquid and
(c~ frGr,l about 0.1 to about 5, preferably from about 1 to
about 3, weight percent, based on the total weight of the
emulsion, of an oil-soluble surfactant.
If desired, the polymer may be recovered by, for example,
coagulation in a large excess of a non-solvent for the
polymer, such as isopropyl alcohol. The polymer may then
be collected by filtration and subsequently dried.
After the polyMer water-in-oil emulsion is prepared, a
water-soluble invertins surfactant may be added thereto.
The polymer in the water-in-oil emulsion containing an
inverting surfactant can be inverted in the presence of
water releasing the polymer into the water in a very short
period of time. The surfactants which may be used include
polyoxyethylene alkyl phenol; polyoxyethylene (10 mole)
cetyl ether; polyoxyethylene alkyl-aryl ether; quaternary
ammonium derivatives; potassium oleate; N-cetyl-N-ethyl
morpholinium ethosulfate; sodium lauryl sulfate;
condensation produces of higher fatty alcohols with
ethylene oxide such as the reaction product of oleyl
alcohol with 10 ethylene oxide units; condensation
products of alkylphenols and ethylene oxide such as the
reaction products of isooctylphenol with 12 ethylene oxide
units; condensation products of higher fatty acid amines
with five, or more, ethylene oxide units; ethylene oxide
condensation products of polyhydric alcohol partial higher
fatty esters and their inner anhydrides (e.g., m~nnitol
anhydride, called Mannitan, and sorbitol anhydride, called
Sorbitan). The preferred surfactants are ethoxylated
D-13,858
~a 22~7~33
- 27 -
nonyl phenols, ethoxylated nonyl phenol formaldehyde
resins, and the like.
The inverting surfactant is used in amounts of from about
0.1 to about 20, preferably from about 1 to about 10 parts
b~ weight per one hundred E)arts by weight of the polyliler.
Although the foregoing process may be employed, the
pre~erred mode of preparing the polymers (i.e., both ter-
and tetra-polymers) of this invention is by a novel
dual-initiator uater-in-oil emulsion polymerization
process disclosed in ~dian Patent Application Serial
No. 448 159-3
The so-called dual-initiator process disclosed in said
application differs from the process descr~bed in said
U. S. Patent No. 4,485 209 in that two
initiators are employed; a first, highly reà~ctive, low
temperature initiator to provide a shear-stable erllulsion,
and a second, less reactive initiator to complete tbe
polymerization at higher temperatures. The presence of a
small amount of polymer formed in situ at low temperatures
by the action of the first initiator provides a highly
stable emulsion resistant to degeneration b~ subsequent
shearing and heating during the course of poly~erization
at higher temperatures. Fur~her, product uniformity i6
greatly improved and gel Sormation i8 minimized and the
2c improved emulsion stability permits greater flexibility in
process design and a broader operating latitude.
D-13,858
.. . . .
` ~Z2S7~33 ~`)
- 28 - .
The first, highly reactive initiator may be a free radioal
initiator capable of initiatiny polymerization of the
mono~ers at a temperature between about 0 and 45C,
preferably between about 20 to 40C to provide a small
amount o~ polymer. The specific amount of polymer thus
produced will vary dependlng upon the monomers employed,
the polymerization conditions, etc, and will be that
amount necessary to provide a shear-stable emulsion.
Examples of suitable initiators are azo compounds such as
2, 2 - azobis (2,4-dimethyl-4-methoxy-valeronitrile) and
peroxy compounds such as potassium pers~lfate, sodium
bisulfite, etc.
The second, less reactive initiator may be a free radical
initiator capable of initiating polyr.lerization of the
monomers at a temperature between about 40 to 100C,
pr~ferably between about 45 to 80C. Examples of suitable
initiators are azo compounds such as 2,2 -azobis (2,4-
dimethylvaleroni~rile) and peroxy compounds such as
benzoyl peroxide.
In the dual-initiator Process twhich is more fullv
described in Canadian Patent Application Serial No.
448,159-3), the first initiator may be added to the reactor
containing the water in-oil emulsion and, after
polymerization has been initiated at a low temperature
(i.e., during the heating up of the ~ontents of the
reactor3 ~nd a small amount of polymer is ~ormed in ~he
emulsion, the second initiator ~ay be ~dded th~reto ~nd
the polymerization continued ~nd completed At ~ higher
tempersture. Alternzt~vely, both the firxt and second
~nitiators ~ay be present ~n the reactor ~r~m the
be~inning of the polymeriz~tion. ghe preferred ~ner of
~dding th* initiators is ~equenti~l (i.e., the s~cond
be$ng added ~fter a small ~mount o~ polymer ls for~ed~.
....
.~j
~,L. `'~
D-13,858
7g3
- -- 2g -- .
An effective method for heat removal, and one which is
preferred, especially in conjunction with the
dual-initiator process, involves the use of an external
heat exchan~er connected to the reactor through a closed
loop. The reaction mixture may be circulated through the
heat exchanger by a pump during the course of
polymerization. Due to the fact that the dual-initiator
process provides a shear-stable water-in-oil emulsion,
such an external heat exchanger may be employed. Under
ordinary conditions, without the improvemerlt afforded by
the dual-initiator process, under the shear field
generated by a high flow capacity pump, the stability of a
conventional monomer emulsion is so marginal that such an
operation cannot be carried out with any reasonable degree
of reliability. In fact, emulsion breakdown often takes
place at the early stages of polymerization leading to the
formation of either coarse emulsion particles or
gelation. Any conventional heat appa~atus rnay be used to
provide the external heat exchange loop. It is preferred
to employ such an external heat exchanger so as to afford
the maximum removal or dissipation of the heat generated
during polymerization. The foregoing advantages should be
obtained, however, regardless of the mechanical design of
the reactor system employed.
Another embodiment of the present invention resides in the
use of the polymers of the invention in flocculating
aqueous solid suspensions. The types of aque~us solid
suspensions that can be treated in accordance with the
present invention include phosphate slimes, suspensions
derived from coal processing operations (such as so-called
blackwater) and other mineral processing (waste) streams
derived from mining of copper, iron (taconite), potash,
kaolin and other clays, bauxite, etc., and other
industrial waste streams such as paper fines, and the like.
D-13,858
~.~Z~ii7~3
- 30 -
The present invention is particularly useful in
flocculating phosphate slimes and coal blackwater
suspension~ employing the polymers of the present
invention.
As described above, the polymers of the inventi~n are
preferably prepared in the form of a water-in-oil emulsion
which contains the polymer in concentrated form within the
aqueous phase. For purposes of the present invention, the
concentrated water-in-oil emulsion may be inverted to form
a concentrated polymer solution which may thereafter be
diluted with additional water. The resulting dilute
solution may be added to the aqueous solid suspension
being treated under appropriate floc-forming conditions,
and thereafter allowing the suspended solids to settle
from the suspension to thereby form an underflow of a more
concentrated solid suspension and an essentially clear
aqueous supernatant.
The concentrated aqueous solution formed from the polymer
water-in-oil emulsion described above generally contains
from about 0.01 to about 1.0, preferably from about 0.1 to
about 0.5, weight percent of polymer, based on the total
weight of the solution. This concentrated solution is
then normally further diluted with additional water to
provide a dilute solution containing from about 0.0005 to
about 0.1, preferably from about 0.~02 to about 0.05,
weight percent of polymer, based upon the total weight of
the dilute solution.
The dilute solution is then mixed with the aqueous solid
suspension at one or more addition points. The amount of
polymer solution employed will vary depending upon a
number of factors, such as the type of aqueous solid
suspension being treated, the desired rate of settling,
degree of compaction and overflow clarity desired as well
- as the particular polymer employed, etc. It is also
D-13,858
~LZZ~i793
- 31 -
obviously desirable to employ the lowest amount of polymer
dosage necessary to achieve a given settling rate, degree
of compaction or overflow clarity, but it is often
difficult to fix effective ranges of flocculant dosages
(expressed either in terms of the weight of polymer per
unit weight of aqueous solid suspension or the amount of
polymer necessary to achieve a certain settling rate) for
certain types of solid suspensions. As an example, the
composition and properties of phosphate slimes obtained
frcr,l the saMe r,lining location may differ substantially.
However, generally speaking, it is commercially desirable
to obtain underflow solids for phosphate slir,~es on the
order of about 12 to 20 weight ~ solids using conventional
- equipment and therefore the polymer flocculant dosage may be adjusted to achieve said degree of compaction.
Alternatively, the polymeric flocculants of the present
invention may be employed in amounts of from about 0.05 to
about 2.0 pounds ~of active poly~er) per ton of suspended
solids, although higher or lower dosages may be employed
depending on the difficulty of flocculating a particular
slime. Similarly, for coal processing waste suspensions,
the polymeric flocculant may be employed in amounts of
from about 0.001 to about 2.0 pounds (of active polymer)
per ton of solid coal fines in suspension to obtain
settling rates of about 5 to 10 inches/minute. Dosages
for other systems May be easily fixed by those skilled in
the art for a particular polymer.
As indiated above, the dilute solution of polymer is
added to the aqueous solid suspension under appropriate
floc-forMing conditions, which include the appropriate or
desired flocculant dosage, the concentration of t~e dilute
flocculant solution, the selection of acceptable or
desired mixing energies to achieve desirably large-sized
flocs and the appropriate contact between the flocculant
solution and the aqueous solid suspension. Upon addition
D-13,858
~22~ 33
- 32 -
. of ~he dilute flocculant solution und~er appropriate
floc-forming conditions, rapid separation of the suspended
solids begins to occur, and with time, the suspended
solids are floccula~ed and settled, thereby forming an
underflow of a more concentrated solid suspension and an
essentially clear supernatant~
The following examples are intended to illustrate the
present invention, sometirnes by comparison wi~h prior art
poly~ers, and are based upon and de~cribe work that was
actually performed. It is not intended to limit the scope
of the present invention to the embodiments described in
the following examples; rather, it is the intention that
the present invention be limited only by the scope of the
claims appended hereto.
Example 1
An aqueous solution containing 79.1 grams of 2-acry}amido-
2-methylpropane sulfonic acid ~-AMPS~) crystals and 92.85
grams of deionized water was neutralized with about 110.79
grams of a 40 weight ~ sodiu~l hydroxide solution to a pH
of about 6.25. The resulting sodium ~AMPSa so}ution was
then mixed with 205.69 grams of a 50 wei~ht % aqueous
solution of acrylamide, 0.03 ~ram of ethylenediamine
tetracetic acid sodium salt, and 23.13 grams of deionized
water. Separately, an oil phase was prepared by mixing
169.75 grams of an aliphatic hydrocarbon (available from
the Exxon Chemical Co. under its tradename Isopar-M), 9.46
grams of sorbitan ~onooleate ~available from ~.C.I. under
its tradename Spa~-80), and 10.64 ~rams of vinyl acetate.
The two phases were combined and homogenized in a Waring
blender to yield a uniform water-in-oil emulsion having a
Brookfield viscosity of 448 centipoises ~cps~Model HBT at
10 R~M at Z5 C). The monomer emulsion w~s transferred to
-~ ~ onæ-liter Pyrex~ l~ss polymeriz~tion kettle ~quipped
D 13,858
- 33 -
with a turbine agitator, a thermo~eter, a condenser, an
addition funnel and a nitrogen (air~ inlet and outlet.
The reactor was deaerated by sparging with nitrogen at a
rate o~ 40G ml/min for u period of about 45 minutes.
Thereafter, a solution of 0.195 gram of 2,2 -a~obis
(2,4-dimethylvaleronitrile)(ava ~a~le from the DU Pont
Company under its tradename VAZO-52) in 9.39 grams of
toluene was prepared and a 20~ portion of the initiator
solution was quickly introduced into the reactor. The
polymerization was initiated by heating the kettle with an
external water bath to about 52C. Once the exotherm took
place, the remaining initiator solution was added into the
reactor at a rate of 0.7 ml/10 min. and the polyrnerization
temperature was l,laintained by a combination of external
cooling and air injection. The latter is a technique to
control the rate of palymeri2ation of the system by
adjusting the dissolved oxygen levels in the mono~er
emulsion usins alternative air and nitro~en s~argin~s.
The polymerization was completed in about 3 hours and a
solution of 0.195 gram of thiobispherlol (available fr~
the Monsanto Chemical Co. unaer its traden~me Santonox-R)
in 5 ~rams of toluene was introduced before discharging
the product. The resultant product was a uniform
water-in-oil emulsion which exl~ibited a Brookfield
viscosity of 704 cps (Model ~BT at 10 RPM at 25C).
Example 2
A portion of the product prepared in Exar,lple 1, weighing
23 10 grams, was coagulated in 400 ml of isopropanol using
a ~aring blender. The coagulated, granular polymer was
~ollected and drled in a vacuum oven ~t 55C. 8.07 grams
of dry polymer were obtained indicating that ~he
conversion W2S e~sentially quantitative.
D-13,858
, ~, . .
~L~2~7~3
- 34 -
Example 3
An 0.3 weight ~ polymer sol~tion was prepare~ by
dissolYing the polymeric eMulsion obtained in Example 1 in
water in the presence of a small amount of a
polyoxyethyleneated linear alcohol (available f~ ~ Union
Carbide Corporation under its tradename Tergit~l-NP 10~.
A very viscous solution was obtainedl and it exhibited a
arookfield viscosity of 1,376 cps (Model HBT at 10 RPM at
25C) and a pH of 6.32.
Example 4
The intrinsic viscosity of the polymer prepared in Example
1 was measured in a one normal sodium chloride solution
and was found to be 8.8 dl/g., indicating the product was
of very hish l~olecular weight.
Example 5
The product prepared in Example 1 (having an I.V. of 8.8
dl/g) was evaluated as a flocculant for coal blackwater at
a dosage of 0.1 pound of polymer per ton of suspended
solids, in combination with 0.1 pound per ton of a
cationic flocculant (available from Allied Colloids under
its tradename Perco~-402) in a cylinder settling test.
Por comparison purposes, tbe combination of 0.1 pound per
ton ~f a sodium acrylate (NaA~-containing anionic polymer
flocculant having an I.V. of 9.5 dl/g (i.e., a 41.1 mole
percent sodium acrylate/54.2 rlole percent acrylamide/4,7
~ole percent ~inyl acetate terpolymer) and 0.1 pound per
. on of Percol-402 w~s used as a control. The cylinder
~ettling test involved plac$ng a coal blackwa~er
~uspension in a cylinder, injecti~g the anionic polymer
~loccul~nt (i.e., the product prepared ln Example l or the
~odium ~cr~ate-conta$ning polymer) into the cylinde,r,
f'''','!~ ~13,eS8
; . . .
~ 35 -
inverting the cylinder 10 times, then injecting the
cationic flocculant into the cylinderJ inverting the
cylinder an additional 10 times and then observing the
rate at which the solids are flocculated and settled. The
results are given in the table below.
Flocculants Settling Hei~ht ~ Solids Content ~*
2 mlns S mins (wt . % )
Example ~ o~vmer
+ Percol'~0~ 77 16 29
NaA polym~
+ Percol 02 67 14 26
* The settling height is expressed as the location
(expressed as a percentaye of the original total hei~ht of
the suspension in the cylinder), after the indicated time,
of the floccul~ted solids/supernatant liquid interface.
*~ The solids content of the compacted material was
determined after 24 ho~rs and is expresse~ as weisht
percent solids.
Example 6
The product prepared in Example 1, and other polymers for
comparison, were evaluated as floc~ulants for a coal fines
suspension in a cylinder settling test, conducted in the
same ~anner as in Example 5. The results are shown in the
ta~le below.
Settling
Rate Percent
Flocculants (inches Trans-
Anionic (lb/to ~ /~in_) _ mission(
Ex. 1 ~0.043 C4(1) (0.08) 13 75
~ (0.02) ~ (0.04) 11 69
q ~0.01) (0.02) 6 63
Nalco~ 872(2) (0.04)Nalco 8B52(3) (0.08) 11 78
~ (~.02) ~ (0.04) 8 77
35~ (0.01) ~ (0.02) 5 60
~-13,~5~
.
~%2~;7~
- 36 -
~,
Superfloc-208(4) (Q.04) Superfloc-355(5) (0.08) 9 83
(0.02) ~ (o,o~) 7 73
( 0 . 01 ) a ( 0 . 02 ) 4 54
Percol-156(6) (0.04) Percol-402(7) (0.08) 8 77
(C.0~) ~ (0.04) 6 70
~ (0.01) ~ (0.02) 4 55
Calgon M295(8) (0.04) Calgon M522D(9) (0.08) 9 76
(0.02) ~ (0.04) ~ ~0
(0.01) ~ ~0.02) 3 30
NaA/AM/VAc(10) (0.04) C4(1) (0.08) 13 76
(0.02) ~ (0.04) 12 73
n (O.01) ~ (0.02) 8 30
Note (1) - A cationic polymer ~locculant obtained from
Rhone-Poulenc, France.
Note (2) - An anionic polyacrylamide flocculant available
from the Nalco Chemical Company as Nalco 8872.
Note (3) - A polymeric cationic flocculant available from
the Nalco Chemical Company as Nalc ~ 852.
Note (4) - An anionic acrylamide copolymer floccula ~ avail-
able from the American Cyanamid Company as Superfloc 208.
Note lS) - A cationic polymer flocculaTMt available from the
American Cyanamid Company as Superfloc 355.
- Note (6) - An anionic polymer flocculant available from
Allied Colloids as Perco ~ 56.
Note (7) - An cationic poiymer ~locculant ~vailable from
Allied Colloids as Perco ~402.
Note ~8) - An anionic polymer 1Occulant ~vailable from
Calgon as Calgo ~ 295.
Note (9) - A cationic polymer flocculant available from
Calgon ~ ~552D.
: ~-13,85~
i7~313
Note (10) - A terpolyme~ic flocculant comprising 41.1 mole
- percent sodium acrylate, 54.2 mole percent acrylamide and
4.7 mole percent vinyl ~cetate.
~ote (11) - Percentage ~ransmission data is given as the
percent transmission after 2 minutes.
Example 7
Example 1 was repeeted with the exception *hat the
polymerization was car~ied out at 45C and the initiator
used was 2,2 -azobis (2,4-dimethyl-4-methoxy-
valeronitrile) (available from the DuTMont Company under
its tradename VAZ0~ 3) inst~ad of VAZ0-52. A uniform,
rnilky, water-in-oil emulsion was obtained. The conversion
was essentially quantit~tive and the resultant product
exhibited the following properties:
PO1YMer Emulsion Viscosity 752 cps
(Model HBT at 10 RPM at 25C)
0.3~ Solution Viscosity 1,376 cps
(Model HBT at 10 RPM at 25Cl
Intrinsic Viscosity, dl/g. ~ 10.0
(in 1 N NaCl Solution)
Exa~ple 8
Example 1 was repeated ~ith the exception that the 10.64
grams of vinyl ~cetate was replaced with the same amount
of styrene. After polymerization, a milky, uniform,
water-in-oil emulsion w~s obtained. The e~ulsion was
ound to contain 31 wei~bt ~ polymer by the isopropanol
coagulation test descri~ed in Example 2. ~n 0.3 weight S
aqueous solution of thi~ polymer exhibited ~ Brookfield
vis~osity of 740 cps (~9odel ~Bl', 10 RPM at 25C).
' ~ D-13,858
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Example 9
.
Example 1 was repeated with the except:ion that the 10.64
gr~ms of vinyl acetate was replaced with the same amount
of alpha-methyl styrene. After polymerization, a milky,
uniform, water-in-oil emulsion was obtained. The emulsion
was found to contain 28 weight ~ polymer by the
isopropanol coagulation test described in Example 2. The
polymer exhibited a~ intrinsic viscosity of 8D8 dl/g
(deciliter/gram) in a 1 N NaCl solution. An 0.3 weight %
aqueous solution of this polymer exhibited a Brookfield
viscosity of 1,380 cps (Model HB'T, 10 RP~ at 25C).
Example 10
A preparative method similar to that employed in Example
1, but usiny a unique dual-initiator sy~tem, was
employed. An aqueous solution containing 138.13 grams of
deionized w~ter and 57.2 grams of ~AMPS~ (Lubrizol Grade
2404) was neutralized with about 22.50 grams of a 50
weight ~ caustic solution to a pH of 7.5. The resultins
sodium "AMPSW solution was then mixed with 283.87 grams of
a 50 wei~ht % aqueous solution of acrylamide, and 0.245
gram of a pentasodium salt of diethylene triamine
pentaacetic acid chelating a~ent (avail~ble from the Dow
Chemical Co. under its tradename Versenex~-80)
Separ~tely, anrMoil phase was prepared by mixing 169.75
grams of Isopar-M, 9.46 grams of Span-80, and 1.9 grams of
~ vinyl acetate. The two pha~es were then combined and
homogenized in a ~aring blender to yield a uniform, milky,
water-in-oil emulsion. The latter exhibited a Brookfield
viscoslty o~ 1,288 cps ~Model ~BT, 10 RPM at 25C). The
~onomer emulsion was transgerred to a one liter
Pyrex~ lass polymerization kettle similarly equipped as
~hat desoribed in Example 1. ~fter deaeration, an
~nl~Ator ~olution co~ t~ng of 0.012 ~ram of VAZC)-33 in
D~13,858
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~t ~ ~
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- 39 -
1.5 grams of toluene was introduced. The kettle
- temperature was raised using an external water bath until
the polymerization was initiated. Therea~ter, ~he
polymerization temperature uas maintained at 50~C by
external coolinq and the air injection technique described
in Example 1. Simultaneously, a second initiator solution
consisting of 0.1755 gram of VAZO 52 in 7.5 grams of
toluene was fed into the reactor at a rate of about 1.5 ml
per every 10 minutes. The polymerization was completed in
about three hours and a solution consisting of 0.195 gram
of Santonox~ in 5 grams of tol~ene was introduced. The
reactor was cooled to room temperature and the product was
discharged. The resultant water-in-oil emulsion possessed
a Brookfield viscosity of 1,128 cps (Model HBT, 10 RPM at
25C). The polymer exhibited an intrinsic viscosity (in 1
~ aCl solution) and a Brookfield solution viscosity tO.3
weight % polymer concentration measured with a HBT Model
at 10 RPM at 25~C) of 10 dl/g and 1,28C cps, respectively.
Examples 11 - 29
Using the procedures described in Example 10, a variety of
AMPS~-containing terpolymers of different compositions
and intrinsic viscosities (molecular weights) were
prepared. The forr,lulation variations and the
characteristics of the finished products are compiled in
the following Table I:
D-13,858
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TABLE I
Terpolymer9
Composition 0.3% Solution
_ _ (Mole %) _ ~AMPS~ Active Viscosity (cps)
Type polymer I.V.4
Example VAc1 Na ~Ar~ps~2 AM3 Used (~) (dl/g) HBT5 LVT6
11 S.5 8.2 86.3 Lubrizol 28.9 11.0 900 3,050
2412
12 i.0 12.3 86.7 2412 29.5 6.0 830 2,000
13 1.0 12.0 87.0 2404 29.5 7.0 5,240 36,700
14 1.0 12.3 86.7 2401 29.5 6.0 V. Low V. Low
1.0 12.0 87.0 2404 29.5 7.5 2,620 13,350
16 1.0 12.0 87.0 2404 25 8.7 1,920 8,200
17 1.0 23.0 87.0 2404 20 11.5 1 570 9,200
18 1.~ 12.0 87.~ 2404 29.5 15.0 2~370 12,000
19 1.0 12.0 87.0 2405 29.5 12.0 1,850 7,600
1.0 12.0 87.0 2405 25 13.5 1,3qO 9,900
21 1.0 12.0 B7.0 2404 20 15.0 1,440 10,800
22 2.7 11.8 85.5 2405 29.5 12.0 1,090 5,050
23 5.1 11.5 83.4 2405 29.5 11.7 1,000 5,200
24 1 14.4 84.6 2405 29.5 12.5 1,440 8,150
0.9 9.9 89.2 2405 29.5 12.0 1,150 5,300
26 0.9 7.8 91.3 2405 29.5 11.0 1,150 3,450
27 0.9 5.9 93.2 2405 29.5 9.0 1,150 2,950
28 1.0 12.0 87.0 2405 25 12.~ 1,470 8,900 t7)
29 1.0 12.0 87.0 2405 25 12.5 1,440 8,800 (8)
(l) VAc = vinyl acetate
(2) Na ~MPS~ = sodium ~AI~PS~
(3) AM = acrylamide
(4) measured in l N NaCl solution
(5) Brookfield viscometer Model HBT at lO RP~I and 25C
(6) Brookfield viscometer Model LVT at 0.6 RPM and 25C
(7) only l/2 of Versenex-80 charge used
(8) twice Versenex-80 charqe used
(9) expressed as the ~ole percentages of the respective
momoners in the starting monomer emulsion
~-13,858
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57~
ExamPle 30
The method of preparation of tetra-polymers containing
both ~AMPS~ and acrylic acid, or their salts, is described
in this example. An aq~eous solution containing 15.82
grams of ~AMPSn, 63.28 ~rams of acrylic acid and 138.13
grams of deionized water was neutralized with about 76.2
g~ams of a 50 weight ~ caustic solution to a final p~ of
7.48. The resulting Na ~AMPS~/Na acrylate solution was
then mixed with 205.69 grams of an aqueous 5~ weight %
acrylamide solution and 0.194 gram of Versenex~80).
Separately, an oil phase was prepared by mixin~ 169.75
grams of Isopar-~, 9.46 ~rams of Span-80, and 10.64 grams
of vinyl acetate. The two phases were then combined and
homogenized in a ~laring blender to yield a uniform, mi}ky,
uater-in oil emulsion. The latter exhibited a ~rookfield
viscosity of 640 cps (Model HBT, 10 RPM at 25C). The
monomer emulsion was then transferred to a one-liter
Pyre~ glass polymerization kettle and was polymerized
using the dual-initiator system in a manner similar to
that described in Example 10. A uniform, ~ilky,
water-in-oil emulsion containing a~out 30 weight % active
polymer was obtained. The emulsio~ and a 0.3 weight
aqueous solution of the polymer exhibited Brookfield
viscosities of 1,048 and 2,496 cps, respectively. The
polymer possessed an intrinsic viscosity of 16.0 dl/g (in
1 N NaCl solution)~
Example 31
3~
The polymer prepared in Example 30 was evaluated as a
flocculant for the dewatering of a Florida phosphate
81ime. A t70 cylinder test was employed and the res~lts
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- 42 -
are shown below:
- Dose
Flocculant (lb/t_n~) t70 (sec)
Example 30 polymer 1 lO.B
None - very long
* lb of active polymer per ton of suspended solids~
The t70 cylinder test was conducted by pouring phosphate
slime and diluted flocculant solution through a funnel
into a breaker containing a rotating rake. The time t70
given in the above table is the time necessary for the
flocculated solids/supernatant liquid interface to fall to
70 percent of the original heisht of the phosphate slime
lS in the cylinder.
Example 32
The polymer prepare~ in Example 30 was evaluated as a
flocculant for the treatment of coal-clay blackwater.
Tests were conducted by measuring both the settling rate
and clarity of the supernatant liquid phase. Two
terpolymers, one containing no sodium ~A~IPS~ and the other
containiny no sodium acrylate, were used as controls:
Flocculant Cs~tl) CCL(2)
Example 30 ~olymer 0.06 0.07
A terpolymer containing 0.14 0.24
no sodium acryl~te (3)
A terpolymer oontaining 0.17 0.12
no ~odium ~AHPS~ (4)
C~
(1 ) SR ~ polymer corlcentratiQn ( #~ton ) *o produce
s~ ling rate of lD ~minute
.
~ " ,
,~,~ D-13,85~
~$~ ` `7 '
- 43 ~ ~S793
(2) CcL = polymer concentration ~#/ton) to
produce supernat~nt clarity of 50%
(3) 8.2 mole ~ Na "AMPS"t 86.3 mole ~ acrylamide/
5.5 mole % vinyl acet~te
(4) 54. 3 mole ~ acrylamide/ 41.1 mole % sodium
~crylate/4.6 mole ~ Yinyl acetate
ExamPleS 33-3?
Using the preparative method described in
Example 30, the following tetrapolymer emulsions
(all having an active polymer content of 29.5 wei~ht
%) were prepared by v~rying the monomer-feed
compositions:
Tatrapolymer5 0.3S Solutlon
Co~ on (Mble S) nAMPSn 2 Vlscoslty (cps)
Ex~m- Na TVP~ I.V. 3 4
pl~VAc "AMPS" NaA1 AM Used (dl/~) H~T LVT
33 0.910 4.3 ~4.8 Lubrlzol 13.2 2,620 10,200
2405
34 0.9 8 ~.3 82.8 2405 14.01,890 11,200
2 0 35 0.96.8 12.0 B0.3 240515.0 1,630 II,B00
36 5.38.3 23.8 62.6 240210.3 1,570 8,550
37 4.7 1.6 39.5 54.2 2402 8.9 2,750 26,550
(I) N~A = sodium acrylate
(2) measured In I ~ NaCI solutlon at 25C
2 5 (3) 8rookfield viscometer Model HBT nt 10 RPM end 25~C
(4) ~rookfield viscometer Model LVT at 0.6 RPM and 25C
(5) Expressed ~s th~ mole percentages of the r0spectlve monomers In
the startlng monomer ~mulslon
E X a mP 1 e 3 8
A series o$ laboratory flocculation tests were
performed on di$ferent Florida phosphQte slimes usin~
different polymer flocculants. These tests were performed
using a 3.5 inch Enviro-Clear labor~tory ~hickener unit
(manufactured by the Enviro-Clear Division of Amstar
D-13,858
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- 44 -
Corporation, Somerville, Ne~ Jersey 08876). In each test,
the raw Florida phosphate slime was metered, uith diluted
polymer flocculant solution, through an in-line static
mixer into the thickener unit, which separated the
combined feed stream into a clear overflo~J liquid (i.e.,
supernatant) and a t~ ckened underflow. Previously-
calibrated Masterflex pumps were used to meter the
phosphate slime, the diluted polymer flocculant solution
and also for the removal of the underflow stream.
Flocculant dosages (expressed as pounds of active polymer
per ton of slimeJ were determined from the measured flow
rates of diluted polymer flocculant solution (of a known
concentration) and slime (both in cubic centimeters/
minute, cc/min) and the weight percent solids of the feed
slime. Underflow solids (expressed as the weight ~ of
solids in the underflow stream) were obtained a~ter 30
minutes running time by removing two underflow samples and
drying them to a constant weig~lt under heat lamps. The
data are reported as tweight %) underflow solids versus
(l~s./ton) flocculant dose in Figures 1-7 of the drawings.
Figure 1 of the drawings compares the flocculatin~
efficiency of four different polymers (identified in Fig.
1 using the same numbers as below) on the same beige
Florida phosphate slime:
~1) the terpolymer of Example 19;
(2) a prior art copolymer believed to contain 12 mole %
sodium ~AMPS~ and 88 mole % acrylamide;
(3) a 75 mole % acrylamide/ 25 mole ~ sodium acrylate
copolymer (available from the Nalco Chemical company under
its tradename Nalc~7873); and
D-lJ,858
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- 45 -
(4) a 54.2 mole % ~c~ylamide/4.7 mole % vinyl
acetate/41.1 mole % sodium acrylate terpolymer (of the
type described in U. S. Patent No.~4,529,782.
Based on ~igure 1, it is
apparent that the terpolymer of the present invention is
significantly more e~ficient, in this slime, than the
other polymers tested, especially at dosages above about
0.1 lbs/ton.
Figures 2 and 3 show the results of similar comparisons,
using the same polyme~s as in Fig. 1, on two different
Florida gray phosphate slimes. Based on the data shown in
Figs. 2 and 3, the polymer of the present invention is
more efficient in th se slimes in comparison to the other
polymers tested.
Figure 4 shows the fl~cculation efficiency, in a beige
~lorida phosphate slime, of:
(1) a 12.4 mole % sodium ~AMPSn/87.6 mole ~ acrylamide
copolymer prepared by a dual-initiator pro~cess as in
Example 10
(2) the terpolymer o~ Example i9; and
(3) a prior art copol~ner believed to contain 12 mole %
sodium ~AMPS~ and 88 mDle g acrylamide.
Pigure 5 shows the fl~ulation efficiency, in a beige
Florida phosphate sli~ believed to be low in Attapulgite
clay/ of:
(1) a sodium ~AMPS~/a~rylamide/vinyl acetate terpolymer,
prepared as in Xxample l;but ~rom ~ monomer emulsion
3s ~ containing 0.8 mole % vinyl acetate, 19.4 mole % sodium
~ AMPS~ and 79.8 mole ~ ~crylamide; and
~25793
- 46 -
(2) the same copolymer designated (1) in ~igure 4.
Figure 6 shows the flocculation efficiency, in a gray
Florida phosphate slime, of:
(1) the same copolymer designated (1) in Fig. 4;
(2) the terpolymer of Example 19; and
(3) and (4) terpolymers prepared as in Example 10, but
starting from a monomer emulsion containing 2.7 mole % and
5.1 mole %" as in Examples 22 and 23 respectively,
vinyl acetate rather than 1 mole ~ as in'Example 19
Figure 7 sho-~s the % underflow solids obtained as a
function of the vinyl acetate contents of the same
polymers as in Figure 6, for two different dosages, in a
different, beige Florida phosphate slime. The data points
on the two curves at 0, 1, 2.7 and 5.1 mole % vinyl
acetate represent polymers designated (1), (2), ~3) and
(4), respectively, in Figure 6, whereas the other two data
points represent two dosages of the prior a~t copolymer
desiqnated (3) in Fig. 4.
Based on the foregoing and the data shown in Figures 1-7,
it will be appreciated that the polymers of the present
invention, generally speaking, are improved flocculants in
comparison to known polymeric flvcculants of the prior art.
D-13,858
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