CA1128730A - System for separating particulate matter into soluble and insoluble portions - Google Patents

Abstract

JLS:pm 1/4/79 Case 5622 TITLE OF THE INVENTION
SYSTEM FOR SEPARATING PARTICULATE
MATTER INTO SOLUBLE AND INSOLUBLE PORTIONS
ABSTRACT OF THE DISCLOSURE
Particulate matter collected by an environmental air quality control device may be in part toxic in nature and thus not readily disposable. By separating the toxic portion of the particulate matter from a nontoxic portion, disposal of nontoxic portion may be more easily accomplished. This separation may be readily effected where the toxic portion is soluble and the nontoxic portion is insoluble, thus allowing the toxic soluble portion to be formed into a solution with a dissolving liquid. The nontoxic insoluble portion then may be filtered from the toxic solution, rinsed, dried and disposed of accordingly.

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Description

Case 5622 ~ t~3~
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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.
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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

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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.
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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 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.

Claims (3)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of separating portions of particulate matter collected pursuant to environmental air quality control requirements so that said particulate matter may be more readily disposed of, said particulate matter comprising a soluble chloride portion and an insoluble metallic oxide portion, said method comprising the steps of:
1) dispensing a controlled amount of said particu-late matter over a substantial area forming an upper end of an inclined trough receiving a controlled volume of a flow of a dissolving liquid comprising substantially water where-in said particulate may be wetted by said liquid, 2) agitating said particulate and said liquid in a dissolving tank connected to a lower end of said trough, 3) forming a slurry of said particulate and said liquid by pumping for proximately 10 minutes said particulate and said liquid in a closed loop path connecting with said dissolving tank, said pumping and said agitation causing said soluble portion of said particulate to dissolve in said liquid and form a solution and suspending said insoluble portion in said slurry, 4) pumping a portion of said slurry into a charge tank to fill said charge tank with a selective volume of said slurry, 5) flowing said slurry in said charge tank into an inlet chamber formed by an upper shell portion of a filtering device further defined by an outlet chamber separated from said inlet chamber by a horizontally disposed section of filter media, 6) applying sufficient air pressure to said inlet chamber of said filter device to cause said solution to flow through said filter media and said insoluble portion to col-lect on said media to form a continuous passage-free cake thereon without said air flowing through said cake, 7) sensing a drop in said air pressure upon a substantial amount of said solution having flowed to said outlet chamber, 8) activating venting means to decrease said air pressure in said inlet chamber to an ambient value upon sensing said pressure drop, 9) filling said charge tank with a selective volume of a rinsing liquid, said rinsing liquid volume being proximately one-half of said slurry volume, 10) flowing said rinsing liquid in said charge tank into said inlet chamber of said filter device, 11) applying sufficient air pressure to said inlet chamber to cause said rinsing liquid to flow through said cake and said filter media to rinse said continuous passage-free cake and remove any further residue of said solution en-trapped in said cake, 12) sensing a drop in said air pressure upon a substantial amount of said rinse liquid having flowed to said outlet chamber, and activating a timing device thereupon, 13) flowing air through said cake to dry said cake for a selective time period as regulated by said timing device, and 14) lifting said upper shell portion of said filter de-vice from said section of filter media to allow said section of filter media and said cake carried thereon to be indexed from said filter device and be disposed of accordingly.

2. A method as defined by Claim 1 and further including the steps of:
15) collecting said solution in a filtrate tank connected to said outlet chamber of said filter device, 16) collecting said rinse liquid in a rinse tank connected to said outlet chamber of said filter device, and 17) adding a volume of said solution in said filtrate tank to said rinse liquid in said rinse tank to form additional dissolving liquid, said solution from said filtrate tank and said rinse liquid in said rinse tank being mixed at a ratio proximating 1 to 1.

3. Apparatus for separating a mass of particulate matter into a soluble portion and an insoluble portion comprising, a receiving means to hold a supply of said particulate matter, a dispensing means to selectively dispense said particulate matter at a controlled rate, a dissolving tank means for receiving a flow of a solvent for dissolving the soluble portion of said particulate matter and said particulate matter, and including an agitating device to mix said particulate matter and said solvent received therein, a slurry forming means for forming a slurry comprising said solvent and said insoluble portion of said particulate matter in suspension, a filter means for receiving said slurry from said slurry forming means and a supply of rinsing liquid, and including an inlet chamber sealably engagable with an outlet chamber selected from said inlet chamber by a filter media, and pressure supply means connected to said filter means inlet chamber to selectively create a pressure force in said inlet chamber to cause said solvent to pass through said filter media whereby said insoluble portion of said slurry forms a cake on said filter media, and to apply a pressure force on said rinse liquid in said inlet chamber to cause said rinse liquid also to pass through said cake into said outlet chamber and thereby washes said cake, and means for transferring said rinse liquid and said solvent from said outlet chamber into said dissolving tank whereby said particulate matter and said solvent may be effectively mixed into said slurry to dissolve said soluble portion of said particulate matter dispensed into said dissolving tank and form said slurry, said insoluble portion in said slurry being separated from said slurry in said filter device as a cake.