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CN104803406A - Method for removing active residual alkali from white mud - Google Patents

Method for removing active residual alkali from white mud Download PDF

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Publication number
CN104803406A
CN104803406A CN201410041005.9A CN201410041005A CN104803406A CN 104803406 A CN104803406 A CN 104803406A CN 201410041005 A CN201410041005 A CN 201410041005A CN 104803406 A CN104803406 A CN 104803406A
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residual alkali
white clay
white
calcium carbonate
alkali
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CN201410041005.9A
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李广
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Abstract

The invention discloses a method for removing active residual alkali from alkali recovery causticized and washed white mud, and belongs to an alkali removal technology in the production process of alkali recovery white mud calcium carbonate. The method comprises the following steps: adding an alkali removal agent into a white mud emulsion generated in the causticizing process, washing the reacted emulsion to remove the white mud active residual alkali, wherein the alkali removal agent is chlorine, calcium hypochlorite or hypochloric acid. The method allows the active residual alkali to be removed from white mud, and is in favor of improving the brightness, the granularity and other physical indexes of the white mud calcium carbonate. The method has the advantages of simplicity, easy operation enforcement, high alkali removal rate, certain whitening effect, obvious saving of water for washing the white mud, and low production cost.

Description

A kind of method removing white clay reactive residual alkali
Technical field
The present invention relates to the treatment process of by product white clay in a kind of papermaking process, be specifically related to the treatment process of calcium carbonate in white clay, while effectively removing white clay reactive residual alkali, the method of further raising white mud calcium carbonate brightness, reduce the distribution range of the diameter of calcium carbonate granule particle diameter, belong to dealkalize and major technique in the production of alkali recovery white slime whiting.
Background technology
If the black liquor that paper industry slurrying production process produces directly discharge can cause serious environmental pollution, therefore people have employed many treatment process and solve pollution problem.The applicant proposes the method for a kind of brand-new alkali collection solid slag comprehensive utilization in Chinese patent application CN101020182A, the method is improved traditional burning and causticization process, solve the secondary pollution that waste residue brings, achieve white clay calcium carbonate superfine powder and activated Calcium carbonate commercialization.
In alkali collection causticization production process, the however, residual base containing 0.5-5wt% in the white clay that causticization produces.When white clay is used for remanufacture calcium carbonate, this however, residual base must be removed, simultaneously, the particle size distribution range of white mud calcium carbonate is too wide, and generally at 2um ~ 50um, size distribution is too wide, produce the application of white mud calcium carbonate and hinder, white mud calcium carbonate quality product is difficult to reach service requirements.
Traditional method is repeatedly washed white clay with water, however, residual base removed.Adopt WATER-WASHING METHOD to produce calcium carbonate and remove residual alkali, because water consumption is large, bath water has part to discharge, and not only processing cost is high, also brings the secondary pollution problem of water; Meanwhile, WATER-WASHING METHOD is long in atmosphere owing to washing rear exposure, and the easy oxidation by air of the iron divalent ion in white mud calcium carbonate is polluted, whiteness is caused to reduce, meanwhile, undressed white mud calcium carbonate size distribution is too wide, is not suitable for production and the application of white mud calcium carbonate product.
Summary of the invention
Object of the present invention is exactly to solve the water consumption of traditional WATER-WASHING METHOD white clay dealkalize process the and affect problem of white clay purification and recover calcium carbonate product quality, study and has invented a kind of dealkalize efficiency is high, method is simple, processing cost is low removal alkali collection causticization and wash rear white clay reactive residual alkali, the brightness of raising white clay, reduce the method for particle size distribution range and change shape.
Remove a method for white clay reactive residual alkali, in turn include the following steps:
(1) by white clay thin up to solid content be the white mud calcium carbonate emulsion of 10-25wt%;
(2) dealkalize agent is added white mud calcium carbonate emulsion, react and stir;
(3) then the mixed solution in step (2) is sent into flow lifting type reactor, reactor is hermetically sealed, reacts and stirs;
(4) after completion of the reaction, mixed solution is sent into dilute with water washing in suction washer, then go white mud calcium carbonate to thicken groove and thicken.
Wherein the concentration of step (1) white mud calcium carbonate emulsion is preferably adjusted to 15-20wt%.
Step (2) dealkalize agent add-on controls according to the content of the residual alkali of white mud calcium carbonate.
The dealkalize agent that step (2) adds is chlorine, hypochlorous acid, Losantin, most preferably is chlorine.
Temperature of reaction in step (3) controls at 15-45 DEG C.
In step (3), the reaction times of mixed solution in flow lifting type reactor is 20 ~ 60 minutes.
Preferably, carbonic acid gas can also be passed in flow lifting type reactor in step (3), further the adjustment shape of white mud calcium carbonate and the homogeneity of particle, and the crystalline form of gained mud calcium carbonate can change, the content of spindle calcium carbonate can be improved, be conducive to the filling at paper industry.Pressure-controlling in step (3) is at 0.10 ~ 2.0MPa, if hypertonia, carbon dioxide-depleted amount is too large, acidifying calcium carbonate too much will generate Calcium hydrogen carbonate, soluble in water, and equipment pressure hazard, cannot bear, if hypotony, in solution, carbonic acid gas is less, cannot meet the effect removed wherein calcium hydroxide, stablize pH value.
The preferred 0.30-1.0MPa of pressure in step (3), by controlling closed reactor pressure valve and carbonic acid gas inlet Valve controlling pressure.
Method of the present invention is simple, enforcement easy to operate, and alkali clearance is high, increases whitening effect simultaneously, and the saving of white clay bath water amount is obvious, and production cost is low.
Adopt traditional WATER-WASHING METHOD dealkalize can cause a large amount of water resource waste, although also someone proposes to adopt customary acid example hydrochloric acid, phosphoric acid, sulfuric acid etc. to neutralize, but the present invention is not only take into account acid-base neutralisation about the selection of dealkalize agent, further find that the dealkalize agent of selecting can improve the quality of white clay effectively, increase the brightness of white clay, meanwhile, the distribution range of calcium carbonate particle diameter can be reduced, the adjustment shape of white mud calcium carbonate and the homogeneity of particle.
Can bleach white clay when selecting chlorine, hypochlorous acid or Losantin, thus function is brightened to white clay.For chlorine:
Its process chemistry reaction formula is as follows:
Cl 2+ H 2o → HClO+HCl(acid chlorine water mixture)
2NaOH+HClO+HCl→NaClO+NaCl+2H 2O
NaOH+HClO+HCl(acid chlorine water mixture) → NaClO (function is brightened to white clay)+NaCl
NaClO also has bleaching and sterilizing effect, and after bleaching and sterilizing, NaClO just changes in order to NaCl; But no matter finally whether transform into NaCl, NaClO is soluble in water, is compared to NaOH, NaCl and NaClO is easy to clear out from calcium carbonate emulsion system in matting thereafter.HClO+HCl(acid chlorine water mixture) number, in the subrange around calcium carbonate particles, formed sour environment, be small-particle by the acidifying of macrobead white mud calcium carbonate particle, simultaneously for reversible reaction, be attached on small-particle calcium carbonate, regenerate relatively oarse-grained calcium carbonate particles, reach the object controlling calcium carbonate granule and shape.
Therefore, the add-on of chlorine is alkali residual with the NaOH(in calcium carbonate emulsion system strictly speaking) amount directly related, residual alkali number is higher, and need the amount of chlorine that adds larger, its relation is as follows:
2NaOH(molecular weight aggregate 80)+Cl 2(molecular weight aggregate 70) → NaClO+NaCl+H2O
That is the chlorine of 70 grams can consume the NaOH of 80 grams.
Beneficial effect of the present invention is as follows:
1, the present invention eliminates the problem that alkali collection causticization washes rear white clay reactive residual alkali preferably, greatly reduce the water consumption of washing white clay, what not only solve that white clay washing brings affects whiteness problem, but also brings benefit to the raising of white mud calcium carbonate brightness;
2, it is convenient that present invention process is simple, operation is implemented, and cost is low;
3, dealkalize rate of the present invention is high, the reactive residual alkali in white clay can be controlled to below 0.05wt%;
4, the present invention can reduce the distribution range of calcium carbonate particle diameter.
Accompanying drawing explanation
Fig. 1 is process flow sheet of the present invention
Embodiment
Below in conjunction with specific embodiment, the invention will be further described.
Embodiment 1
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35 ~ 70wt%(solid content) white mud calcium carbonate thicken 22wt%(solid content), measuring its residual alkali content is 1.0wt%, and white clay brightness is 86%, and pH value is more than 14.
(2) by chlorinating machine chlorine added in white clay emulsion and react and stir, control the flow control of soda-residue emulsion liquid pump at 20m3/h, (i.e. residual alkali 44kg per hour), control chlorine and added by chlorinating machine, with the change adding rear quality before chlorine adds, determine that adding amount of chlorine is 16.2kg/h;
(3) then enter flow lifting type reactor to continue react and stir, the reaction times is 30 minutes, then removes the residual alkali of part through washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 11.2, white clay brightness 87.2%; Residual alkali content 0.05wt%), particle size distribution range 3um ~ 30um.Embodiment 2
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 22wt%(solid content), measuring its residual alkali content is 1.0wt%, and white clay brightness is 86.1%, and pH value is more than 14.
(2) by chlorinating machine chlorine added in white clay emulsion and react and stir, control the flow control of soda-residue emulsion liquid pump at 20m 3/ h, (i.e. residual alkali 44kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 20.3kg/h;
(3) then enter flow lifting type reactor to continue react and stir, the reaction times is 40 minutes, then removes the residual alkali of part through washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 11.0, white clay brightness 87.0%; Residual alkali content 0.045wt%, particle size distribution range 4um ~ 25um.Embodiment 3
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 22wt%(solid content), measuring its residual alkali content is 1.0wt%, and white clay brightness is 86.2%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 44kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 27.4kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the reaction times is 40 minutes, washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 11.0, white clay brightness 88.2%; Residual alkali content 0.03wt%, particle size distribution range 5um ~ 16um.
Embodiment 4
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 22wt%(solid content), measuring its residual alkali content is 1.0wt%, and white clay brightness is 86.2%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 44kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 30.5kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the stirring reaction time is 40 minutes, washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 10.7, white clay brightness 87.9%; Residual alkali content 0.02wt%, particle size distribution range 3um ~ 11um.
Embodiment 5
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 20wt%(solid content), measuring its residual alkali content is 0.8wt%, and white clay brightness is 85.4%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 32kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 25kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the stirring reaction time is 50 minutes, washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 10.5, white clay brightness 89.0%; Residual alkali content 0.01wt%, particle size distribution range 3um ~ 11um.
Embodiment 6
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 20wt%(solid content), measuring its residual alkali content is 1.5wt%, and white clay brightness is 86.2%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 60kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 25kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the stirring reaction time is 50 minutes, washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 11.3, white clay brightness 86.2%; Residual alkali content 0.04wt%, particle size distribution range 3um ~ 25um.
Embodiment 7
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 20wt%(solid content), measuring its residual alkali content is 2.5wt%, and white clay brightness is 84.5%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 100kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 25kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the stirring reaction time is 50 minutes, washing, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 12.3, white clay brightness 85.2%; Residual alkali content 0.32wt%, particle size distribution range 3um ~ 40um.
Embodiment 8
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 20wt%(solid content), measuring its residual alkali content is 0.8wt%, and white clay brightness is 85.4%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 32kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 25kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the stirring reaction time is 50 minutes, passes into carbonic acid gas simultaneously, and temperature of reaction is 20 DEG C, and reactor pressure controls, at 0.40MPa, then to wash, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 11.0, white clay brightness 89.8%; Residual alkali content 0.008wt%, particle size distribution range 3um ~ 11um.
Embodiment 9
Remove a method for white clay reactive residual alkali, comprise the steps:
(1) by causticization come concentration be 35wt%(solid content) white mud calcium carbonate thicken 20wt%(solid content), measuring its residual alkali content is 1.5wt%, and white clay brightness is 86.4%, and pH value is more than 14.
(2) to be added in white clay emulsion by chlorine by chlorinating machine and react and stir, the flow control of soda-residue emulsion liquid pump is at 20m 3/ h, (i.e. residual alkali 60kg per hour), is controlled chlorine and is added by chlorinating machine, with the change adding rear quality before chlorine adds, determines that adding amount of chlorine is 25kg/h.
(3) then enter flow lifting type reactor to continue react and stir, the stirring reaction time is 50 minutes, passes into carbonic acid gas simultaneously, and temperature of reaction is 20 DEG C, and reactor pressure controls, at 0.40MPa, then to wash, bath water amount 3m 3/ T(over dry white clay), measuring result after reaction: emulsion pH value is 11.0, white clay brightness 86.8%; Residual alkali content 0.02wt%, particle size distribution range 3um ~ 11um.
Fig. 1 is shown in the technical process of embodiment 1-9, and test result is in table 1.
The test result of table 1 embodiment 1-9
As can be seen from Table 1, the residual alkali content of the white clay adopting treatment process of the present invention to obtain reduces, brightness improves, pass into white mud calcium carbonate spindle body crystalline form that carbon dioxide process obtains in flow lifting type reactor and rectangle crystalline form content higher, be more conducive to the application of paper industry.
In table 1, product crystalline form content is measured by X diffraction approach.
Above-described embodiment is only and the present invention and enumerating is described, not for limiting the present invention, the structure of any effects equivalent converted based on the technical program, all belongs to protection scope of the present invention.

Claims (9)

1. remove a method for white clay reactive residual alkali, in turn include the following steps:
(1) by white clay thin up to solid content be the white mud calcium carbonate emulsion of 10-25wt%;
(2) dealkalize agent is added white mud calcium carbonate emulsion, react and stir;
(3) then the mixed solution in step (2) is sent into flow lifting type reactor, reactor is hermetically sealed, reacts and stirs.
2. remove the method for white clay reactive residual alkali according to claim 1, wherein the concentration of the described white mud calcium carbonate emulsion of step (1) is 15-20wt%.
3. remove the method for white clay reactive residual alkali according to claim 1, wherein in step (2), the add-on of dealkalize agent controls according to the content of the residual alkali of white mud calcium carbonate.
4. remove the method for white clay reactive residual alkali according to claim 1, wherein said dealkalize agent is chlorine, hypochlorous acid, Losantin.
5. remove the method for white clay reactive residual alkali according to claim 4, wherein said dealkalize agent is chlorine.
6. remove the method for white clay reactive residual alkali according to claim 1, the temperature of reaction wherein in step (3) controls at 15-45 DEG C.
7. remove the method for white clay reactive residual alkali according to claim 6, the temperature of reaction wherein in step (3) controls at 20 DEG C, and the reaction times is 20 ~ 60 minutes.
8. remove the method for white clay reactive residual alkali according to claim 1, wherein pass into carbonic acid gas in step (3) flow lifting type reactor, pressure-controlling is at 0.10 ~ 2.0MPa.
9. remove the method for white clay reactive residual alkali according to claim 8, wherein said pressure-controlling is at 0.10 ~ 2.0MPa.
CN201410041005.9A 2014-01-28 2014-01-28 Method for removing active residual alkali from white mud Pending CN104803406A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3268388A (en) * 1963-08-20 1966-08-23 Glatfelter Co P H Manufacture of calcium carbonate
CN1042743A (en) * 1989-09-01 1990-06-06 四川省乡镇企业造纸协会 Soda recovery process of small paper mill and equipment
US20070051482A1 (en) * 1997-05-21 2007-03-08 Olsen Gary A Method for kraft waste reclamation
CN101759220A (en) * 2009-11-03 2010-06-30 武汉晨鸣汉阳纸业股份有限公司 Method for self-production of calcium carbonate filler by white mud obtained by alkali recovery
CN102976387A (en) * 2012-12-07 2013-03-20 陕西科技大学 Improved preparation technology of white mud calcium carbonate for papermaking filler

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3268388A (en) * 1963-08-20 1966-08-23 Glatfelter Co P H Manufacture of calcium carbonate
CN1042743A (en) * 1989-09-01 1990-06-06 四川省乡镇企业造纸协会 Soda recovery process of small paper mill and equipment
US20070051482A1 (en) * 1997-05-21 2007-03-08 Olsen Gary A Method for kraft waste reclamation
CN101759220A (en) * 2009-11-03 2010-06-30 武汉晨鸣汉阳纸业股份有限公司 Method for self-production of calcium carbonate filler by white mud obtained by alkali recovery
CN102976387A (en) * 2012-12-07 2013-03-20 陕西科技大学 Improved preparation technology of white mud calcium carbonate for papermaking filler

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Application publication date: 20150729