Note: Descriptions are shown in the official language in which they were submitted.
Case 5622
~ t~3~
. ' ~
BACKGROUNI) OF T~IE INVE2tTION
Field of t~e Invention
_._
This invention relates to the ~reatmen~ of pa~ticulate
matter collected, for example, pursuant to ~n en~ironmental
air qualit~ control requirement. Disposal ~ the particulate
may be more readily accomplished by separating the particulate
into portions having different physical and chemical char-
acteristics.
Description of the Prior Art
Leaching whereby a substance is subjected to a flow of
liquid to remove a soluble portion of the substance is well
known. One example in years past is wood ashes being leached
with water to produce lye, i.e. a strong, alkaline solution.
The lye was then used to make soap.
~ eaching has also proved to be valuable in processing
baghouse dust collected pursuant to environmental air cuality
control requirements apolicabl~ to a galvanizing process.
This dust or particulate contains proximately 50 percent
insoluble aluminum and zinc oxides which are nontoxic. .A
remainder cf the dust is toxic being primaril~ soluble
aluminum, zinc and ammonia chlorides. The insoluble portion
being nontoxic could be disposed of as a landfill while the
soluble portion reused ln the formation of gaLvanizing
fluxes.
One method of separating the soluble and insoluble
portions is the use or^ vacuum ~iltration after the dust and
w2ter are counte.cur~Qntl~ mix~d in two to rive stases.
SUL~R~ O ~ T~ VENTIO~
_
. eeder clis?enses at a s212c=ive rat2 a qu~ntity of
dry parriculate matt2r into a st-eam of dissol~Jins liquid
373~ ca s e 5622
.
running down an inclined trough. The particulate matter and
liquid 10w into a dissolving tank where the li~uid and
particulate matter are for~ed into a slurry b~ an agi~ator
and a ~ilter charging pump which pumps the slurry in a
closed loop path to and from the dissolving tank. The
soluhle portion of the particulate matter is completely
dissolved to form a solution with the dissolving liquid
while the undissolved portion is placed in suspension.
The slurry is then pumped to a filter charging tank
which in turn fills an inlet chamber OL a filter device
separated rrom an outlet chamber by a section of filter
media. By applying air pressure to the inlet chamber, the
solution is forced through the filter media whereon the
undissolved particulate portion collects to form a cake.
The solution is collected in a filtrate tank.
Clean dissolving liquid is then introduced under pressure
into the inlet chamber of the filtering device to rinse the
cake and remove any residue of the solution remainlng in the
cake. The cake then may be air dried. This rinsing liquid
is collected in a rinse tank.
The solution in the filtrate tan~ and the liquid in the
rinse tanX, as required, may be blended to form addltional
dlssolving liquid for further mixing with the dry particulate
matter rrom the dispenser.
This inventive svstem has several advantages.
First, this system provides superior se~ar~tion of the
soluble and insoluble ?articulate matter por~ion so as to
provide a toxic-rree substance allowing ready disposition.
SecondLy, the ~ystem may ~e so controlled .o operate
continuously in ~hat the _iltering devi~e ~iil produce
": -
Case 5622
3~ 731E3
successive batches of the insoluble particùlate matterportion.
Thirdly, the solution produced is reusable i concsn-
tratad, Lor example by heating. Thus, the amount o solution
which must be disposed of and the amount of new make-up
chemicals which must be added may be minimized i~ desired.
DESCRIPTION OF THE DRAWINGS
-
FIG. 1 is a schematic diagram of this system for
separating particulate matter into soluble and insoluble
portions.
DESCgIPTION OF THE PREFERRED El~BODIl~tFNT
A system for separating a soluble and a nonsoluble
portion of a dry particulate matter is shown generally in
FIG. 1 and designated 10. The system 10 includes a bin 12
in which a particulate matter P may be conveniently stored.
To a bottom of the bin 12 is attached a dispenser 14 which
is located over an upper end 16 or a downwardly inclined
sluice trough 18. A lower end 20 o~ the trough 18 is posi-
tioned over an open top end of a dissolving tank 22.
The dissolving tank 22 includes an agitator 24 to
improve mixing therein. A filter charging ~ump 26 having an
intake 28 connects to a bottom outlet 30 in the tanX 22
through a first valve 32. A discharge 34 o L the charglng
pump 20 in turn connects with a T-ritting 36 which in turn
ia joined to a second and a third valve 38, i'O.
The second valve 38 is further connected to a dissolving
2~ tan~ return ?ipe 2 while the third valve ~'0 is joined to a
rlrst top lnlet 4~' of a charge tank A, 6. .~ bottom outlet ~'8
of the char~e tank ~6 connecta with a rourtn valve 50.
-
Case 5522
~.2~73~
Additionally, the charging tank ~6 has a second top inlet 52
which connec~s with a source S or clean dissolving liquid
through a fith val~e 54.
A filtering device 56 is di~ided horizontally into a
movable upper shell portion 58 forming a top inlet chamber
60 and a ixed lower shell portion 62 forming an outlet
chamber 6d by a section of filter media 66. The inlet
chamber 60 is connected to the fourth valve S0. The section
of filter media 66 may be of a disposable nature and supplied
from a roll 68 located external to the filter de~ice 56.
The inlet chamber 60 of the filter device 56 is rurther
connected to a vent valve 70 and an air supply valve 72.
The outlet chamber 64 of the filtering device 56 is joined
to a discharge line 74 which in turn connects with an inlet
76 of a filtrate tank 78 through a sixth valve 80. This
discharge line 74 also connects ~ith a rinse inlet 82`of a
rinse tanX 84 through a seventh valve 86.
The filtrate tanX 78 has a bottom outlet 88 which is
linXed to an intake 90 of a transfer pump 92 through an
eighth valve 94. A discharge 96 of the transfer pump 92 in
turn connects with a T-ritting 98 which rurther joins with
a ninth valve 100 and a tenth valve 102. The ninth valve
100 connects the transler pump 92 to an external using means
M (not shown) while the tent~ valve 102 joins the transfer
pump 92 to a rlltrate inlet 104 of the rlnse tank 84. A
bottom outlet 106 of the rinse tank 84 connects ~ith the
upper end 16 or the sluice trough 13 through an el-venth
valve 108 and a dissolver cha_ge ?ump 110.
During the initial o~erati~ cycle or the system 10,
the ri~se tank 3g initiall~ wlll contaLn a dlsaoi~Jing liauid,
in this cas2 water. r,~ith the eleventh valve 108 o~en and
Case 5622
3~
the dissolver charge pump 110 energized, water i3 pumped at
a controlled rate to the upper end 15 o~ trough 13 The
dispenser 14 is activated to meter out at a controlled rak~
the dry par-ticuLate P from the bin 12 into the water flow i~
the trough 18.
In this 2mbodiment, the dry particulate is a dust
collected by an air pollution control system connected to a
galvanizing line located external to the system 10. A
portion of the dust is water soluble and comprises aluminum,
zlnc and am~oniumchlorides which are toxic in nature. These
chlorides, being soluble in water, would contaminate a
surrounding area if disposed of as a landfill. The insoluble
portion of the dust comprises nontoxic aluminum and zinc
oxides. The optimum ratio of water to dust has been found
to proximate 9 to 1 so as to produce a 10 percent dust
concentration.
It should be understood that the system 10 of this
invention is not limited to this particular application but
could be applied to a number of waste Products whlch may not
be readily disposed OL without further processingO
~nen the desired amount of dust and ~rater are present
in the dissolving tank 22, the eleventh valve 108 is closed
and the dissolver charge pump 11~ and the dis~enser 14 de-
energi~ed.
During the rlow o dust and water into the dissolving
tan~ 22 rom the lower end 20 of the trougn 18, the agitator
24 is activated so s .o form a ,lurr~ of the dust and
water. r~hen the dissolving tan~ 22 has been so charged, the
first valve 32 and second valve 38 a-e o~ened, the third
valve 40 closed, and the rllter charge ?ump 26 energi3ed.
-~By pumping the water and dus~ in a clos~d loop path rom the
Case 5622
3~
bottom outlet 30 of the dissolving tank 22, through the
filter charge pump 26 and back into the dissol~ing tan~ 22
by means of the rQturn pipe 42, the dust and water are
thoroughly mixed. After lO minutes of such circulation, the
soluble portion o~ the dust has dissolved in the water to
form a solution while the remaining insoluble portion is
placed in suspension.
Upon completion or this mixing, the second valve 38 is
closed and the third valve 40 opened allowing the slurry to
be pumped into the filter charge tank 46 to a precise level
as controlled by a level control switch operatively connected
to the second and third valves 38, 40. With the filter
charge tank 46 filled as noted above, the third valve 40 is
again closed and the second valve 38 again opened allowing
the slurry in the dissolving tank 22 to continue to circulate.
When the filter charge tank 46 is full, the fourth
valve 50 and the vent valve 70 are opened for a sufficient
time duration to allow the slurry in the rllter char~e tank
46 to drain into the inlet chamber 60 of the filter device
56. The fourth valve 50 and the vent valve 70 are then
closed while the air supply valve 72 and the sixth valve 80
are opened. A controllsd flow of compressed air enters the
inlet chamber 60 o~ the filter devics 56 so as to increase
the prsssurs level ~ithin the inlet chamber 60 to proximately
~5 2i ~si. Under this pressure, the solution of watsr and
dissolved portion or the dust in the slurrv is rorced through
the se~tion or ilt=r media 66 in the iltsring device 56.
As this solution passes through the filter media 66, the
undissolved ~ortion of the dust is separated thers-rom to
~orm a graduall~ incr~singl~ thick ca~ce on ths section or
filter media 66.
-
Case 5622
. .
731LJ9
Once substantially all the solu~ion in the filterdevice 54 has been forced into the filtrate ~anX 78 through
the dischaxge line 74, the pressure in the inlet c~am~er 60
drops because there is less resistance to the flow o air.
Upon this drop in pressure ~ithin the inlet chambex ~eing
sensed, the air supply valve 72 is immediately closed to
prevent the caXe rom becoming overly dry and cracking.
Concurrent with the closing of valve 7~, the si~th valve 80
is also closed.
At the same time that the vent valve 70 and the fourth
valve 50 were closed after the slurry filled the filter
devica inlet chamber 60, the fifth valve 54 was opened so as
to fill the filter charge tank 46 with clean rinse water to
a level such that the amount of rinse water i5 proximately
equal to one-half the amount of the slurry. The fifth valve
S4 is then closed. As noted above, when the air supply
; valve 72 and six~h valve 80 were closed, the fourth valve 50
and the vent valve 70 are then opened allowing the clean
water in the filter charge tank 46 to drain to the inlet
chamber 60 and cover the cake OL the undissolved portion of
the dust.
The fourth valve ~0 and the vent valve 70 are again
closed while the air supply valve 72 and the seventh valve
86 are opened to selectively force the clean water in ~he
inlet chamber 60 through the cake and rinse rrom the cake
any residue of the solution. This rinse ~ater flows into
the rinse tank 8~.
When substantially all or the clean WatQr 'nas been
forced through the cake, a drop in air prPssure in the
fLlt-r device Lnlet cnamber 60 activates the timer allowing
air to -low for a selective time period into the inlet
--7--
Case 5622
J~ 3~
cham~er 60 through the cake to dry such. At the end of this
drying period, the seventh valve 86 and the air suppl~ t~al~ts
72 are closed and the vent valv~ 70 opened. The inLet
chamber 60 of the filter device 56 is thus returned to
atmospheric pressure.
To remove the cake of undissolved portion of the dust,
the upper shell portion 58 of the filter device S~ is raised
from the lower shell portion 62. The section of filter
medla 66 may be supported on a filter media conve~or ~not
shown) allowlng that section to be indexed forward. The
media and the cake may be conveniently deposited in a
receptacle 112. The cake as so deposited will contain less
than 1 percent soluble chlorides. As the section of filter
media 66 is being indexed forward, a new clean section of
filter media is drawn from the roll 68 and positioned between
the upper and lower filter device shell portions 58, 62.
The upper shell portion 58 then may be lowered to again form
a seal with the lower shell portion 6~.
As can be seen from FIG. 1, the capacity of the filtrate
tank 78, the rinse tank 84 and the dissolving tank 22 are each
substantially greater than the filter charse tan~ 46. This
- allows the filter device portion o the syst~m 10 to continue
to operate even ir another portion of the system is down.
Since the rinse tank 84 may contaln one-half or ~he
2i amount of liquid required to rorm the slurry needed to flll
; the filter charge tank 4O, additional liquid ~ust be added
to the rinse t~n~ 84. This li~uid may be obtained from the
filt-ate tank 78 which cqntains the sQlution of wat~r and
; dissolved chlorides from previous cycles. By ooening the
eighth valve 94 and the tenth valv2 102, closing the ninth
valve 100 and energizing the transfer pump 92, the rinse
Case 5622
8~3~
tank 84 may be filled to a seLective level as controlled by
a level switch operati~vely connected to the heretofore
mentioned valves 94, 100, 102 and the pump 92.
If the filtrate tank 78 is not sufficientLy emptied b~
this transfer of the solution to the rinse tank 84, t~e
ninth valve 100 may be opened and the tenth tJalve 102 closed
allowing the solution in the filtrate tank 78 to be pumped
to the external consuming means M. Pumping the solution
from the filtrate tank 78 to the means M may also be effected
independent of the rinse tank illing procedure if such is
required.
With a sufficient amount of liquid in the rinse tank
84, the dissolving tanX 2~ may ~e filled as required to
supply the filter charge tank 46. This filling is accom-
plished as noted earlier by opening the eleventh valve 108and activating the dissol~ing charge pump 110 and the
dispenser 14.
Note that the concentration af dissolved chlorides in
the liquid pumped rom the rinse tank 84 is sufficiently
below the saturation point so as to insure that the ~hlorides
in the dust mixed with that liquid are effectively dissolved.
Note further that the procedure o emptying the riltrate
tank 78, filling the rinse tank 8a from the filtrate tank 78
and filling the dissolving tank 22 may be substantially
independent or the cycling of the filter device ~6 because
of the larger capacity of tnese three tanks 22, 78 and 8~.
While various modif~cations may be sugg~st~d by those
versed in the art, it should be understood that we wish to
embody within the scope of the pa~ent warr2nted hereon, all
3G such modifications as reasona~ly and ?roperly come within
the sco~e of our contri~ution to the art.
