Note: Descriptions are shown in the official language in which they were submitted.
wo 96/40439 PcT/u~ r5~s
METHOD OF DEPRESSING NON-SULFIDE SILICATE GANGUE MINERALS
BACKt~ROUND OF INVFI\ITION
The plt7sehl invention relates to froth flolalion p,-,cesses for recovery of value sulfide
minerals from base metal sulfide ores. More particularly, it relates to a method for the
depr~s~ n of non-sulfide silicate gangue minerals in the ber-efici~tion of value sulfide
minerals by froth ~lolalion procedures.
Certain theory and p,~clice states that the success of a sulfide flotation process
10 clepen.l~ to a great degree on reagents called l~ ~"ectors that impart selective hydrophobicity
to the mineral value which has to be separated from other minerals.
Certain other i-~ o,ld,1L reagents, such as the modifiers, are also r~sponsiL)le for the
succes~ful rlolalion separation of the value sulfide and other minerals. Modifiers include,
but are not nece.ss~rily limited to, all reagents whose principal function is neither collecting
15 nor frothing, but usually one of modifying the surface of the mineral so that it does not float.
In ad~ilion to a~ ,np~ at making sulfide cn"ectors more selective for value sulfide
minerals, other approaches to the pl.k' ~, of improving the flotation separation of value
sulfide minerals have included the use of modifiers, more particularly dep,~ssal,ls, to
depr~ss the non-sulfide gangue minerals so that they do not float along with sulfides
20 thereby reducing the levels of non-sulfide gangue minerals reporting to the concerll-ales.
A IJepr~ssant is a "lo~irier reagent which acts selectively on certain unwanted minerals and
prevents or inhibits their flotation.
In sulfide value mineral rlol~lion, certain non-sulfide silicate gangue minerals present
a unique pr~t'o " in that they exhibit natural floatability, i.e. they float independent of the
2~ sulfide value mineral l~ "e~,lor:i used. Even if very selective sulfide value mineral collectors
are used, these silicate minerals report to the sulfide concenllclles. Talc and pyrophyllite,
both belonging to the class of magnesium silicates, are particularly troublesome in that they
are naturally highly hydluphobic. Other magnesium silicate minerals belonyi"g to the
classes of olivines, py,w~enes, and sel~.el,lil,e exhibit various degrees of flo~t~hi'ity that
30 seems to vary from one ore deposit to the other. The pr~sence of these unwanted minerals
in sulfide value mineral concenll~les causes many pr.~'o us i.e. a) they increase the mass
of the concenll~les thus adding to the cost of handling and transpo, l~lion of the
concenl,~le, b) they compete for space in the froth phase during the flotation stage thereby
reducing the overall sulfide value mineral recovery, and c) they dilute the sulfide concentrate
35 with respect to the value sulfide mineral content which makes them less suitable, and in
WO 96/40439 PCT/U' ,. ~G~
some cases unS~iph~Q~ for the smelting thereof because they interfere with the smelting
ope,~lion.
The deprtssanls co~""only used in sulfide flotation include such materials as
inorganic salts (NaCN, NaHS, SO2, sodium met~h~ lfite etc) and small amounts of organic
compounds such as sodium thioglycolate, mercaptoethanol etc. These depr~ssanls are
known to be c,F~t'e of depr~ssi-lg sulfide minerals but are not known to be depressanl~i
for non-sulfide minerals, just as known value sulfide collectors are usually not good
collectors for non-sulfide value minerals. Sulfide and non-sulfide minerals have vastly
d;ffer~"l bulk and surface chemlcal prupe,lies. Their response to vaRous chemicals is also
vastly differ~:"l. At present, certain polysaccharides such as guar gum and carboxy methyl
cellulose, are used to depr~ss non-sulfide silicate gangue minerals duRng sulfide flotation.
Their perfommance, however, is very variable and on some ores they show unacceplable
depr~ssant activity and the effective dosage per ton of ore is usually very high (as much
as 1 to 10 Ibs/ton). Their deprt:ssa-,l activity is also influenced by their source and is not
consislenl from batch to batch. F~"lhe""ore, these polysacchaRdes are also valuable
sources of food i.e. their use as depressants reduces their usage as food and, storage
thereof presents particular pr~ble.-~s with regard to their attractiveness as food for vemmin.
Lastly, they are not readily miscible or soluble in water and even where water solutions
thereof can be made, they are not stable. U.S. Patent 4,902,764 (Rothenberg et al.)
desc,ibes the use of polyacrylamide-based synthetic copolymers and terpolymers for use
as sulfide mineral depr~ssanls- in the recovery of value sulfide minerals. U.S. Patent
4,720,339 (Nagaraj et al) desc,ibes the use of polyacryla", r,' based synthetic copolymers
and terpolymers as depr~ssanl~ for silicious gangue minerals in the flotation beneficiation
of non-sulfide value minerals, but not as dep,~ssanl:j in the benefication of sulfide value
minerals. The '339 patent leaches that such polymers are effective for silica depressiûn
duRng phosphate flotation which also in the ~lul~liûn stage uses fatty acids and non-sulfide
collectors. The p~ ,lees do not teach that such polymers are effective depr~ssants for
non-sulfide silicate gangue minerals in the recovery of value sulfide minerals. In fact, such
depr~ssanls do not exhibit adequate dep,~ssanl activity for non-sulfide silicate minerals
during the bene~icialion of sulfide value minerals. U.S. Patent 4,220,525 (Petrovich)
teaches that polyhydroxyamines are useful as dep,essanl:j for gangue "~;"er~ls including
silica, silicates, ca,bonates, sulfates and phosphates in the recovery of non-sulfide mineral
values. Illustrative examples of the polyhydroxyamines d;sclosed include aminobutanetRols,
aminopartitols, aminohexitols, aminoheptitols, aminooctitols, pentose-amines, hexose
amines, amino-tetrols etc. U.S. Patent 4,360,425 (Lim et al) desc,il,es a method for
WO 96/40439 PCTJUS96/06481
improving the results of a froth flotation ~rucess for the recovery of non-sulfide mineral
values wherein a synthetic depr~ssa"l is added which conlaills hydroxy and carboxy
functionalities. Such depressants are added to the second or amine stage flotation of a
double float process for the purpose of depr~ssi"y non-sulfide value minerals such as
5 phosphate minerals during amine flotation of the siliceous gangue from the second stage
concenl~le. This patent relates to the use of synthetic de,c~ssanl during amine flotations
~ only.
In view of the foregoing and especially in view of the teachings of U.S. 4,902,764
which teaches the use of certain polyacryla"~ based copolymers and terpolymers for
10 sulfide mineral depr~ssion during the recovery of value sulfide minerals, we have
unexpectedly found that certain polymers, alone or in conjunction with polysaccharide, are
indeed excellent depr~ssa"ls for non-sulfide silicate gangue minerals (such as talc,
p~"uxenes, olivines, serpentine, pyrophyllite, chlorites, biotites, amphiboles, etc). These
synthetic polymer depr~ssa"ls and blends with polysaccharides have now been found to
1~ be excellent altematives to the polysaccharides used currently alone since they are readily
m;scil,!c or soluble in water, are non-hazardous and their water solutions are stable. The
use thereof will increase the availability of polysaccharides as a valuable human food
source and their performance is not variable. The polymers, moreover, can be
manufactured to adhere to sl,ing~r,l speciricalions and, accordingly, batch-to-batch
20 consislency is guaranteed. The synthetic polymers lend ll,e",selves readily to modiricalion
of their structure, thereby pe""illi"~ tailor-making of depr~ssanl~ for a given application.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a method which
co"~rjrises benericialing value sulfide minerals from ores with the selective rejection of non-
sulfide silicate gangue minerals by:
a. providing an aqueous pulp slurry of finely-divided, liberation-sized ore
particles which contain said value sulfide minerals and said non-sulfide
silicate gangue minerals;
b. con.lilion;ny said pulp slurry with an effective amount of non-sulfide silicate
gangue mineral depr~ssanl, a value sulfide mineral collector and a frothing
agent, said dep,~ssanl co",pris;~ either (1) a polymer of polyvinylalcohol
to which is grafted an acrylamide monomer and, optionally, a comonomer
copolymerizable with said acrylamide monomer, or a mixiture of said
W O 96/40439 PCTAJS96/06481
polymers, or (2) a blend of said polymer or polymers and a polysaccharide
and
c. collecting the value sulfide mineral having a reduced content of non-sulfide
silicate gangue minerals by froth ~lol~lion.
DESCRIPTION OF THE INVFI~JTION INCI IIDING PRFF~RF~Fn Fl\~IBODIMENTS
The polymer depr~ssanls used in the present invention may co" ,p,ise as the grafted
monomers, such acryla",~ s as acrylamide per se, alkyl acryla",- -s such as
methacrylan,-de, ethacrylamide and the like.
The co"~ono",ers may co",prise any monoethylenically unsaturated monomer
copolymerizable with the acrylamide monomer such as hydroxyalkylacrylates and
methacrylates e.g. 1,2-dihydroxypropyl acrylate or methacrylate; hydroxyethyl acrylate or
methacrylate; glycidyl methacrylate, acrylamido glycolic acid; hydroxyalkylacrylamides such
as N-2-hydroxyethylacrylamide; N-1-hydroxypropylacrylamide; N-bis(1,2-
dihydroxyethyl)acryla. ". ; N-bis(2-hydroxypropyl)acrylamide; and the like, acrylic acid;
methacrylic acid; alkali metal or a~mon um salts of acrylic and/or methacrylic acid; vinyl
sulfonate; vinyl phosphonale; 2-acrylamido-2-methyl p,upane sulfonic acid; styrene sulfonic
acid; maleic acid; fumaric acid; crotonic acid; 2-sulfoethylmethacrylate; 2-acrylamido-2-
methyl propane phosphon-.~ acid acrylonitrile; vinyl alkyl ethers such as vinyl butyl ether,
and the like.
The effective weight average molecular weight range of the polyvinylalcohols is
sul,ulisi,,yly very wide varying from at least about ten thousand, pr~r~bly from about
thirty thousand to millions e.g. 2 million p,~erably to about 1 million
The polysaccharides useful as a co"~ponenl in the depr~ssa"l compositions used
in the process of the present invention include guar gums; r"o~i~ied guar gums; cellulosics
such as carboxymethyl cellulose; starches and the like. Guar gums are p,~fer,~d.The ratio of the polysaccharide to the grafted polymer in the depr~ssant co",posilion
should range from about 9:1 to about 1:9 respectively pr~ bly from about 7:3 to about
3:7, respectively, most pf~r~bly from about 3:2 to 2:3"~spec;li-/ely.
The dosage of depr~ssanl useful in the method of the present invention ranges from
about 0.01 to about 10 pounds of depressanl per ton of ore, preferably from about 0.1 to
about 5 Ib./ton most pr~7~er~bly from about 0.1 to about 1.0 Ib./ton of ore. O
When mixtures of the grafted polyvinylalcohol polymers discussed above are used
as the dep,~ss&nt, they may be used in ratios of 9:1 to 1:9 preferably 3:1 to 1:3 most
WO 96/40439 PCT/US96/06481
p,~rclbly 3:2 to 2:3, ~~:spe~;tively.
The weight ratio of the acrylamide to the polyvinyl alcohol in the depressants used
herein should range from about 99 to 1 to about 1 to 1, p,~r~rdbly from about 10 to 1 to
about 4 to 1 respectively. The conce"l,dlion of the optional copolymerizable comonomers
should be less than about ~0% as a weight percent fraction, preferably from about 1 to
about 30% of the total Illonolllei~.
The acrylamide monomer grafted polyvinylalcohol may be pr~par~d by any method
known to those skilled in the art such as that taught in EPO-A-117978; Melnik et al; Dokl.
Akad. Nauk Uter. SSR Ser B; Geol. Khim. Brol. Nanki (6) 48-51 Russian 1987; Burrows
et al; J. Fl~ulo~;he~. Pll. b!~. A,63(1), 67-73, English, 1992. Generally, the ac~ylamide
monomer, alone or in conjunction with the optional coi"ono",er, may be grafted onto the
polyvinylalcohol in the pr~sence of ceric ion catalyst, e.g. ceric ammonium nitrate, as a
catalyst at a ter"perdlure ranging from about 10-50~ with inl~""illent cooling for from about
2-6 hours. Temmination of the reaction is ~r~ectt:d after a consla,ll solution v;scosily is
reached by raising the pH with diluted caustic solution to neutral or above. Generally the
amount of catalyst employed should range from about 0.3 to about 5.0% by weight, based
on the combined weignt of monomers to be grafted, pr~erably from about 0.8 to about
4.0%, same basis, the pr~"ed range resulting in a grafted polymer having a more
effective depr~ssanl activity.
The new method for bene~icidli~,g value sulfide minerals employing the syntheticdepr~ssanl:j of the present invention provides eA~ 'lurgical recovery with improved
grade. A wide range of pH and depr~ssant dosage are pe"";ssible and col-,paliL)ility of the
dep,~ssanl~ with frothers and sulfide value mineraH. G'le tUI:~- is a plus.
The pr~senl invention is di,~;tecl to the selective removal of non-sulfide silicate
gangue minerals that nommally report to the value sulfide mineral flotation concentrate either
because of natural floatability or hyd,~"~hn~ city or otherwise. More particularly, the instant
method effects the depr~ss;on of non-sulfide magnesium silicate minerals while enabling
the enhanced recovery of sulfide value r~.:ne,~ls. Thus, such materials may be treated as,
10 but not limited to, the following:
Talc
Pyrophyllite
Pyroxene group of Minerals
Diopside
Augite
Homeblendes
Enstatite
Hypersthene
WO 96/40439 PCT/U' ,~OC,181
Ferrosilite
Bronzite
Amphibole group of minerals
Tremolite
Actinolite
Anthophyllite
Biotite group of minerals
Pl,ogo~
Biotite
Chlorite group of minerals
Se" enli"e group of minerals
Serpentine
Chrysotile
Palyyorsl~ile
Lizardite
1 5 Anil~orile
Olivine group of minerals
Olivine
For~lerile
Hortonolite
Fayalite
The f~loJ~ e~d~ es are set forth for purposes of illustration only and are not to
be construed as limitations on the present invention except as set forth in the appended
claims. All parts and per~enlayes are by weight unless otherwise specified. In the
examples, the ~ollo.~,;ng desi~ale the monomers used:
AMD = acrylamide
PVA = polyviny!- -hol
AA = acrylic acid
MAMD = methacrylamide
AN = acrylonitrile
VBE - vinylbutylether
t-BAMD = t-butylacrylamide
HPM = 2-h~dlux,ulupyl methacrylate
AMPP = 2-acrylamido-2-methylpr~pane phosphon-c acid
CMC = carboxymethyl cellulose
C = comparative
Rs-ckground FY~-nple 1
Prer~r~tion of Ceric Ammonium Nitr~t~ ~tAIyst solution
54.82 parts of ceric amrnon Im nitrate (0.1 M) are dissolved in one liter of 1.0 N nitric
acid.
Background Example 2
Gr~ft Copolymeri7~tion
To a solution of 5.0 parts of polyvinyl alcohol (mol. wt. approx. 10,000) in 150 parts
WO 96/40439 PCT/US~6/OC~81
of water, 30.9 parts of a 52% acrylamide monomer solution are added. With good agitation
5 parts of the above ceric catalyst solution are introduced slowly. The reaction mixture is
kept at 25- 30~C with i~,le,l"ill~l,l cold water cooling. The graft polymerization is continued
for 3 to 4 hours until a cunsldnl solution viscosity is obtained. The reaction is terminated
5 by raising the pH of the mixture with diluted caustic solution to a neutral or slightly alkaline
pH.
e~ck~round FY~lnDles 3 and 4
FlollDw:.,g the above Example 2, graft copolymers of AMD and PVA of higher
molecular weight, i.e., 20,000 and 50,000, are also prepared.
P~ckground FY~mple 5
A graft terpolymer is prepared by adding 30.9 parts of a 52% acrylamide monomer
solution and 7.2 parts of acrylic acid monomer to a solution of 5.0 parts of PVA (mol. wt.
50,000) in 150 parts water. A total of 10 parts of ceric catalyst solution are used for this
pr~pardlion. Other copolymers are pf~par~d similarly, e.g. using acrylorlill !e and vinyl butyl
1 5 ether.
FXAMPI FS 1-10
An ore containing ap,~,ruxi,,~ately 3.3% Ni and 16.5% MgO (in the form of Mg
silicates) is ground in a rod mill for 5 min. to obtain a pulp at a size of 81% -200 mesh. The
ground pulp is then lldnsrerled to a ~lot~lion cell and is conditioned at natural pH (~8-8.5)
with 150 parts/ton of copper sulfate for 2 min., 50 to 100 parts/ton sodium ethyl x~nlilale
for 2 min. and then with the desired amount of a dep,~ssa"l and an alcohol frother for 2
min. First stage ~luldlion is then conducted by passi"g air at ap,c r~xi"~alely 3.5-5 Umin. and
a concenl~ale is ~ t~d In the second stage, the pulp is condilioned with 10 parts/ton
of sodium ethyl xanthate, and specified amounts of the clepr~?ssanl and the frother for 2 min.
and a cor,cenll~le is c~"ecled. The condilions used in the second stage are also used in
the third stage and a concenll~te is collected. All of the ~lol~lion products are filtered, dried
and assayed.
The results for the depr~ssanl activity of two AMD/PVA graft copolymers are
co"lpar~d with that of guar gum and polyvinyl-'c~hol in Table 1. In the absence of any
cle,c ,tssant, the Ni recovery is 96.6% which is considel~d very high and desirable; the MgO
recovery is 61.4% which is also very high, but considered highly undesirable. The Ni grade
of 4.7% obtained is only slightly higher than that in the original feed. With guar gum at 420
and 500 parts/ton, the MgO recovery is in the range of 28.3 to 33.5% which is considerably
lower than that obtained in the absence of a deprt~ssant, and Ni recovery is about 93%
which is lower than that obtained in the absence of depr~ssal-l. A reduction in Ni recovery
WO 96/40439 PCT/US96tO6481
is to be ~Ypected in the pr()cess of reducing MgO recovery since there is invariably some
mineralogical associalion of Ni minerals with the Mg-s:'~c~les and, when the latter are
d~pr~ssed, some Ni minerals are also de~,essed. When the graft copolymers of thepresent invention are used, there is a much greater reduction in the MgO recoveries
5 co"lpared to that with guar gum. The Ni recoveries are also slightly lowered compared with
that of guar gum, but the Ni grades in the concenl.dle are much higher than those obla:. ,ed
with guar gum. These findings indicate the very strong cle,c,~ssanl activity of the graft
copolymers at all of the ~os~es used. They also suggest that much lower clos~es of the
graft copolymers can be used; in this case the Ni recoveries would improve while10 maintaining the low MgO recoveries.
The results also de",on~l,dle that when a polyvinyl alcohol polymer is used as is,
i.e., without grafting to the AMD monomer, the metallurgical perforrrlance is poor;
depr~ssanl activity is quite non-selective. The Ni recovery is greatly reduced (82.9% vs.
the recovery of 88% for the graft copolymer under identical con.lilions). Thus the graft
15 copolymer is much superior to as-is poly~inyl alcohol.
Table 1
Feed Assay: 3.31% Ni snd 17.58% MgO
ExampieDepressant PartstrOn Ni Ni MgO
Rec. Grade Rec.
1 C None 0 96.6 4.7 61.4
2C Guar Gum 350+70+80 93.0 7.7 28.3
3C Guar Gum 300+60+60 92.9 6.7 33.5
4AMD/PVA(23K)75/25 300+70+80 91.6 9.2 18.7
5AMD/PVA(23K)75/25 350+85+100 90.1 9.6 14.2
6AMD/PVA(23K)75/25 350+70+80 90.0 8.3 20.7
7AMD/PVA(23K)75/25 280+56+64 90.6 7.5 23.0
8AMD/PVA(50K)75/25 350+70+80 88.0 9.5 16.7
9AMD/PVA(50K)75/25 280+56+64 84.8 7.8 17.3
lOC PVA(50K) 350+70+80 82.9 6.4 38.1
W O 96/40439 PCT~US96/06481
FX A M pl FC 11-70
The gangue silicate minerals from the same ore as in Examples 1-10 are treated
with a dosage of depr~ssanl of 1.0 Ib./ton unless oU ,elwise specified in accor lance with the
~luldlion procedure thereof. The results are set forth in Table ll, below, the lower the value
5 under the column heading % Recovery (gangue silicate) the better the depressanl.
T~ble ll
% Recovery
Example D~ ress- ~t (Gangue Silicate)
11 C None 85
12C Polyvinyl alcohol 75
1 3C Guar 3.4
14 60/40AMD/PVA 8.9
75/25 AMD/PVA 8.7
16 80/20 AMD/PVA 3.0
17 87/13 AMD/PVA 1.3
18 90/10 AMD/PVA 0
19 92.5/7.5 AMD/PVA 7.9
97.5/2.5 AMD/PVA 7.8
FXAMPI F~ 21~24
A PVA graft copolymer is prepared in acco,.lance with Background Examples 1-5
above, with varying amounts of ceric iron catalyst. The results are shown in Table lll
below ~ J;ng the ~lol~lion procedure of Exa"lF es 11-20.
WO 96/40439 PCT/U~ ~G~'~,G181
Table lll
% % Recovery
Example De,l~ress~.~t Catalyst (Ce)(Gangue Silicate)
21 75/25 AMD/PVA 0.5 44.6
22 75/25 AMD/PVA 1.3 8.7
23 75/25 AMD/PVA 1.96 3.0
24 75/25 AMD/PVA 2.6 2.6
FXAMpl FC 25-28
The llu~alion procedure of Exdlllr~es 11-20is again followed except that different
graft copolymers are employed. The results are set forth in Table IV below.
Table IV
% Recovery
15 Example Depre~sal)t (Gangue Silicate)
AMD/AN/PVA 80/10/10 7.75
26 AMD/AN/PVA 85/5/10 3.28
27 AMD/AA/PVA 66/24/10 16.60
28 AMDNBE/PVA 80/10/10 14.70
FXAMPLES ~9-31
The flotation procedure of E)~dll,ples 11-20 is again followed except that the mc'ec~'qr
weight of the PVA is varied. The results are shown in Table 5, below.
Table V
% Recovery
Example DepressantMolecular Wt. (PVA) (Gangue Silicate)
90/10 AMD/PVA 9-10K 7.1
36 90/10 AMD/PVA 13-23K 4.6
37 90/10 AMD/PVA 31-50K 3.3
WO 96/40439 PCT/US96~ G~81
FXAMpl F 38
The flotation procedure of Exarrr'es i-10 is again f~ v~,d except that the
dep,t7ss&.ll is a 1:1 blend of the de,c,~:ssant~ of Example 8 and Example 27. Similar results
are ach 2ved.
,. 5
EXAMPI FC 39-42
An ore containing ap,c,r~J~i",ately 3.3% Ni and 16.5% MgO (in the fomm of Mg
silicates) is ground in a rod mill for 5 min. to obtain a pulp at a size of 81% -200 mesh. The
ground pulp is then lr~nsr~r,~d to a rlulalion cell and is cunditiuned at natural pH (-8-8.5)
with 150 parts/ton of copper sulfate for 2 min., 50 to 100 parts/ton sodium ethyl xa,lt~,ale
for 2 min. and then with the desired amount of de,ur~ssanl blend and an alcohol frother for
2 min. First stage nolalion is then conducted by passing air at appr~ximdtely 3.5-5 Vmin.
and a concerll,dle is collected. In the second stage, the pulp is condilioned with 10
parts/ton of sodium ethyl ~ "ll,-dte, and specified amounts of the depr~ssanl b,end and the
15 frûther for 2 min. and a concenl~dte is collected. The conditions used in the second stage
are also used in the third stage and a conce"ll~le is collected. All of the rloldliûn products
are filtered, dried and assayed.
The results for the depr~ssanl activity of a 1:1 blend of AMD/PVA graft copolymer
with guar gum is compared with that of guar gum alone and the graft copolymer alone at
20 the same dosage in Table Vl. In the abse"ce of any dep,~ss&"l, the Ni recovery is 96.6%
which is consider~d very high and desirable; the MgO recovery is 61.4% which is also very
high, but considered highly undesi,dble. The Ni grade of 4.7% obtained is only slightly
higher than that in the original feed. With guar gum at 500 parts/ton, the MgO recovery is
28.3%, which is considerdbly lower than that obtained in the absence of depr~ssanl, and
25 Ni recovery is about 93% which is also lower than that ol,lained in the al)sence of a
depr~ssanl. A reduction in Ni recovery is to be e~peu~ed in the prucess of reducing MgO
recovery since there is invariably some mineralogical association of Ni minerals with the
Mg-silicates and, when the latter are de,cressed, some Ni minerals are also dep,~ssed.
With the AMD/PVA graK copolymer at the same dosage, there is siy"iricanl reduction in
3û MgO recovery cul"parl:~l with that of guar gum. In the case of the biend ûf guar gum and
synthetic polymer at the same dosage, however, there is further increase in the dep,t:ssanl
activity compar~d with that of the two co,nponenls individually. The grade of the Ni in
concenlrdle also increases. The results also suggest that much lower dos~ges of the blend
can be used; in this case the Ni recoveries would improve while maintaining the low MgO
35 recoveries.
11
WO 96/40439 PCT/US9Gi ~ 6~$81
Table Vl
Feed Assay: 3.31% Ni and 17.58% MgO
Example De,vressant Partstron Ni Ni MgO
Rec. Grade Rec.
39C None 0 96.6 4.7 61.4
40C Guar Gum 350+70+80 93.0 7.7 28.3
41C AMD/PVA (23K) 75/25 350+70+80 90.0 8.3 20.7
42Guar Gum and AMD/PVA (23K) 350+70+80 88.6 9.2 18.7
75/25; 1:1
FYsimples 43-53
When the procedure of Examples39-42 are again followed except that the
15 dep,~ssa"l co",poner,l~ are varied as are their concenlr~lions as set forth in Table Vll
below similar results are achieved.
WO 96/~0439 PCT/US9G,U6~181
Tablc Vll
Polysaccllaride GP:PS
5ExampleGrafted Polymer (GP) (PS) Ratio
43AMD/AN/PVA 80/10/10 Guar Gum 9:1
44AMD/PVA (50K) 75/25 CMC 4:1
45AMD/AA/PVA 66/24/10 Starch 1~1
46AMD/PVA 97.5/2.5 Guar Gum 1:9
10 47AMDIAN/PVA 8515110 Modified Guar 2:3
48 AMD/PVA 87/13 Starch 3:2
49AMDNBE/PVA 80/10/10 Guar Gum 2:1
AMD/PVA* CMC 1: 1
51 AMDIPVA (9-10K) Guar Gum 3:2
15 52 AMD/PVA(13-23K) Guar Gum 3:2
53 AMD/PVA (31-SOK) Guar Gum 3:1
*Made with 2.6% of Ce catalyst.
13
