CN109534365B - Cyclic manufacturing method for co-production of sodium bicarbonate and ammonium chloride - Google Patents
Cyclic manufacturing method for co-production of sodium bicarbonate and ammonium chloride Download PDFInfo
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- CN109534365B CN109534365B CN201910000924.4A CN201910000924A CN109534365B CN 109534365 B CN109534365 B CN 109534365B CN 201910000924 A CN201910000924 A CN 201910000924A CN 109534365 B CN109534365 B CN 109534365B
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- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 title claims abstract description 299
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 title claims abstract description 180
- 229910000030 sodium bicarbonate Inorganic materials 0.000 title claims abstract description 150
- 235000017557 sodium bicarbonate Nutrition 0.000 title claims abstract description 149
- 235000019270 ammonium chloride Nutrition 0.000 title claims abstract description 88
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 38
- 125000004122 cyclic group Chemical group 0.000 title claims abstract description 9
- 238000005185 salting out Methods 0.000 claims abstract description 69
- 239000012452 mother liquor Substances 0.000 claims abstract description 66
- 238000002425 crystallisation Methods 0.000 claims abstract description 61
- 230000008025 crystallization Effects 0.000 claims abstract description 60
- 238000001556 precipitation Methods 0.000 claims abstract description 42
- 238000000926 separation method Methods 0.000 claims abstract description 35
- 238000000034 method Methods 0.000 claims abstract description 29
- 238000006243 chemical reaction Methods 0.000 claims abstract description 13
- 230000001376 precipitating effect Effects 0.000 claims abstract description 6
- 239000007788 liquid Substances 0.000 claims description 44
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 38
- 235000002639 sodium chloride Nutrition 0.000 claims description 32
- 239000013078 crystal Substances 0.000 claims description 31
- 238000003860 storage Methods 0.000 claims description 23
- 238000010438 heat treatment Methods 0.000 claims description 22
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical class O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims description 21
- 239000011780 sodium chloride Substances 0.000 claims description 20
- 239000000725 suspension Substances 0.000 claims description 19
- 239000001099 ammonium carbonate Substances 0.000 claims description 16
- 239000012267 brine Substances 0.000 claims description 16
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 15
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 15
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 14
- 238000000354 decomposition reaction Methods 0.000 claims description 13
- 150000003839 salts Chemical class 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000001035 drying Methods 0.000 claims description 12
- 238000004064 recycling Methods 0.000 claims description 12
- 150000001450 anions Chemical class 0.000 claims description 8
- 230000008014 freezing Effects 0.000 claims description 8
- 238000007710 freezing Methods 0.000 claims description 8
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 7
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 6
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 6
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 6
- 230000008719 thickening Effects 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 5
- 229920006395 saturated elastomer Polymers 0.000 claims description 4
- 239000006228 supernatant Substances 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 2
- 230000001737 promoting effect Effects 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 13
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000002360 preparation method Methods 0.000 abstract 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- 239000000047 product Substances 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000011734 sodium Substances 0.000 description 8
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 7
- 230000009471 action Effects 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009958 sewing Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- -1 anion sodium salt Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000010070 molecular adhesion Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 238000010587 phase diagram Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000009938 salting Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- UIIMBOGNXHQVGW-UHFFFAOYSA-N sodium;hydron;carbonate Chemical compound [Na+].OC(O)=O UIIMBOGNXHQVGW-UHFFFAOYSA-N 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D7/00—Carbonates of sodium, potassium or alkali metals in general
- C01D7/02—Preparation by double decomposition
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/16—Halides of ammonium
- C01C1/164—Ammonium chloride
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a cyclic manufacturing method for co-production of baking soda and ammonium chloride, which comprises the steps of primary baking soda precipitation, cold precipitation crystallization, salting-out crystallization and mother liquor circulation which are sequentially carried out, wherein a secondary baking soda precipitation step is arranged between the salting-out crystallization and the mother liquor circulation and is used for further precipitating baking soda from baking soda mother liquor (I-II) generated after the salting-out crystallization. The preparation method of the invention can reduce the energy consumption of recovering ammonium chloride by cold separation crystallization, efficiently produce and obtain sodium bicarbonate and ammonium chloride, simultaneously realize the full circulation of the mother liquor generated by reaction in the production process, and has simple process and low production cost.
Description
Technical Field
The invention relates to the technical field of chemical production, in particular to a method for producing baking soda (NaHCO 3) by adopting a double decomposition method, and specifically relates to a cyclic manufacturing method for preparing baking soda and co-producing ammonium chloride.
Background
In the production process of preparing baking soda and coproducing ammonium chloride by adopting a double decomposition method, NaCl, NaHCO 3 and NH 4 Cl are contained in separated baking soda mother liquor, wherein sodium bicarbonate is in a saturated state, in the prior art, the mother liquor is directly frozen and added with NaCl for salting out, and the sodium bicarbonate is precipitated along with ammonium chloride due to supersaturation, so that the quality of an ammonium chloride product can not meet the requirement of the national standard (the Na + content in the agricultural ammonium chloride of 92-year edition is regulated in the national standard: the Na + content in the agricultural ammonium chloride is less than or equal to 1.4%); and the nitrogen content in the ammonium chloride product does not reach the national standard of 25 percent.
If the mother liquor is directly discharged, ammonia nitrogen can seriously pollute river water sources, and evaporation is mostly used for recovering ammonium chloride and salt in order to not discharge waste water, but the method has more defects that the total amount of ammonium chloride and sodium chloride in the mother liquor is not more than 200g/L, 5-6 tons of water need to be evaporated for each 1 ton of ammonium chloride to be recovered, 0.8 ton of coal is consumed, and in addition, the evaporated salt can hardly reach the industrial standard. These factors make the industrial application of the double decomposition method difficult and the economic practicality is poor.
Chinese patent CN102107889B discloses a method for processing ammonium chloride in baking soda mother liquor at normal temperature, specifically discloses a method for processing baking soda mother liquor dehydrated by a filter and a centrifuge, cooling the baking soda mother liquor to normal temperature, adding the baking soda mother liquor into an ammonia separating kettle, adding hydrochloric acid to control the content of free ammonia in the baking soda mother liquor to be less than 1.3%, and controlling the pH value to be 6.5-7.1; reacting hydrochloric acid with free ammonia and a trace amount of ammonium bicarbonate to generate ammonium chloride, and reacting hydrochloric acid with a trace amount of sodium bicarbonate to generate sodium chloride; the method has the advantages of higher hydrochloric acid consumption and higher process cost, and the sodium bicarbonate is not recycled from the salted-out mother liquor, and the yield of the sodium bicarbonate is 60-80%.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the provided circular manufacturing method for co-production of baking soda and ammonium chloride can reduce the energy consumption of recovering ammonium chloride by cold separation crystallization, efficiently produce baking soda and ammonium chloride, realize the full circulation of mother liquor generated by reaction in the production process, and has the advantages of simple process and low production cost.
The technical scheme adopted by the invention for solving the technical problems is as follows: a cyclic production method for co-production of baking soda and ammonium chloride comprises primary baking soda precipitation, cold precipitation crystallization, salting-out crystallization and mother liquor circulation which are sequentially carried out, and the method also comprises a secondary baking soda precipitation step arranged between the salting-out crystallization and the mother liquor circulation and used for further precipitating the baking soda from the baking soda mother liquor (I-II) generated after the salting-out crystallization.
Further, the method comprises the steps of:
(1) first-stage separation of sodium bicarbonate: adding saturated brine and ammonium bicarbonate into a reaction kettle for double decomposition reaction to generate sodium bicarbonate, filtering the obtained sodium bicarbonate, washing, dehydrating and drying;
(2) and (3) cold separation and crystallization: taking brine generated by the baking soda generated in the separation step (1) as baking soda mother liquor (I), conveying the baking soda mother liquor into a crystallization kettle, adding a divalent anion accelerant into the crystallization kettle, controlling the temperature to be 15-20 ℃, freezing for 2.5-4 h, crystallizing and separating out ammonium chloride, and filtering and dehydrating the obtained ammonium chloride;
(3) salting out and crystallizing: overflowing sodium bicarbonate mother liquor (I-I) generated after cold separation crystallization from the crystallization kettle to a salting-out kettle, simultaneously adding sodium chloride into the salting-out kettle, controlling the temperature to be 20-25 ℃, further crystallizing and separating out ammonium chloride, settling to a crystal pulp outlet of the salting-out kettle, and returning ammonium chloride crystal pulp to the crystallization kettle in the step (2);
(4) and (3) secondary sodium bicarbonate precipitation: sodium bicarbonate mother liquor (I-II) generated after salting-out crystallization overflows to a thickening tank from a salting-out kettle, flows to a heating kettle through the bottom of the thickening tank, is separated out at the temperature of 35-45 ℃, and is dehydrated and dried to obtain sodium bicarbonate;
(5) mother liquor circulation: and (3) collecting brine generated by separating ammonium chloride and brine generated by separating the baking soda in the second stage in the separation step (4) into a second-stage liquid storage tank, and returning supernatant in the second-stage liquid storage tank as baking soda mother liquor (II) to the step (1) for recycling.
Further, the divalent anion stimulator added in the step (2) is ammonium sulfate.
Further, in the step (1) and the step (4), the washing process is to wash out chloride ions by adopting water or saturated pure alkaline water at the temperature of 35-45 ℃.
Further, a stirrer is arranged in the position, away from the bottom 1/4-1/2, of the secondary liquid storage tank in the step (5), the bottom of the secondary liquid storage tank is communicated with the heating kettle, and the stirrer is used for returning suspension at the bottom of the secondary liquid storage tank to the heating kettle to precipitate the baking soda again.
Furthermore, the components in the baking soda mother liquor (I) are controlled to be 80-120 g/L, NH 4 g/120 g/L, NH 4 Cl 170-220 g/L, SO 42-1-8 g/L of NaCl.
Furthermore, the components in the baking soda mother liquor (II) are controlled to be NaCl 210-300 g/L, NH 4 HCO 350-70 g/L, NH 4 Cl 50-80 g/L, SO 42-1-8 g/L.
Further, the device adopted by the method comprises a primary sodium bicarbonate precipitation device, a cold precipitation device, a salting-out device and a circulating device which are sequentially communicated, and a secondary sodium bicarbonate precipitation device, wherein one end of the secondary sodium bicarbonate precipitation device is communicated with the salting-out device, the other end of the secondary sodium bicarbonate precipitation device is communicated with the mother liquor circulating device, the salting-out device comprises a salting-out kettle and a salt feeding device, the salt feeding device is communicated with the salting-out kettle and used for adding reaction promoting salt into the salting-out kettle, and the feeding end of the salting-out kettle is communicated with the cold precipitation device and used for collecting overflow liquor discharged by the cold precipitation device and carrying out salting-out crystallization on the overflow liquor.
Further, the salting-out kettle comprises a clear liquid section, a connecting section and a suspension section, wherein the height of the suspension section is 1.5-3 m.
Further, the suspension section is provided with at least one crystal pulp taking-out opening, the crystal pulp taking-out opening is formed in the position which is far from the top end 1/2-3/4 of the suspension section, and the crystal pulp taking-out opening is communicated with a liquid discharging pipe in the center of the top of the crystallization kettle.
Compared with the prior art, the invention has the following advantages:
1. when the double decomposition method is adopted to prepare the baking soda and the ammonium chloride is co-produced, the technical process is not single to generate solid baking soda and liquid ammonium chloride, wherein the solid phase containing the baking soda is provided with the ammonium chloride, the ammonium bicarbonate and the sodium chloride; the liquid phase contains sodium bicarbonate, sodium chloride, ammonium chloride and ammonium bicarbonate; in the cold separation crystallization stage, ammonium sulfate serving as a divalent anion accelerant is added into a crystallization kettle, and the crystallization of ammonium chloride is accelerated under the same ion effect and the action of divalent anion accelerant, compared with the condition that the ammonium chloride crystal can be separated out only by freezing for 8-10 hours at the temperature of 5-10 ℃ in the direct freezing process, the ammonium chloride crystal can be separated out only by freezing for 4 hours at the temperature of 15-20 ℃, so that the energy consumption of recovering ammonium chloride by cold separation crystallization is reduced, the energy and the time are saved, and the economy is higher.
2. And a step of secondary sodium bicarbonate precipitation is added, sodium bicarbonate mother liquor (I-II) generated after salting out and crystallization overflows to a concentration tank, flows to a heating kettle from the bottom of the concentration tank, and (NH 4) 2 SO 4 in the heating kettle is rapidly converted into Na 2 SO 4 at the temperature of 35-45 ℃, wherein the Na 2 SO 4 can promote the formation and increase of sodium bicarbonate crystals, inhibit ammonium chloride from crystallizing and precipitating, and improve the yield and purity of the sodium bicarbonate.
3. The method adopts five steps of primary sodium bicarbonate precipitation, cold-precipitation crystallization, salting-out crystallization, secondary sodium bicarbonate precipitation and mother liquor circulation to circularly produce the sodium bicarbonate and coproduce ammonium chloride, improves the yield and the nitrogen content of the ammonium chloride by twice crystallization of the cold-precipitation crystallization and the salting-out crystallization, and improves the yield and the purity of the sodium bicarbonate by twice sodium bicarbonate precipitation of the primary sodium bicarbonate and twice sodium bicarbonate precipitation of the secondary sodium bicarbonate.
4. According to the invention, hydrochloric acid is not consumed to control the content of free ammonium in the baking soda mother liquor, the process is simple, the production cost is low, the yield of each product reaches 95-98%, and the content of nitrogen in the obtained ammonium chloride product is about 24%.
Drawings
FIG. 1 is a process flow diagram of a cyclic manufacturing method for co-production of sodium bicarbonate and ammonium chloride according to the present invention;
FIG. 2 is a schematic diagram of the salting-out kettle shown in FIG. 1.
Reference numerals: 1-clear liquid section, 2-connecting section, 3-suspending section, 4-crystal pulp taking-out port, 5-primary sodium bicarbonate precipitating device, 6-cold separating device, 7-salting-out device, 8-secondary sodium bicarbonate precipitating device, 9-ammonium chloride processing device, L1101-reaction kettle, T1102-brine tank, L1103-ammonium bicarbonate feeding device, P104, X124-vacuum filter, V105-separating tank, V106-primary liquid storage tank, V125-secondary liquid storage tank, X108, X129, S122-centrifugal machine, F109-drying device, K110, K130-sack closer, OK 111-sodium bicarbonate finished product, P113-ice maker, V117-low tank, V121-dense tank, L2121-1-heating kettle, P119-pulp sending pump, OK 131-ammonium chloride finished product, P115-external cooler, T1116-crystallization kettle, T1118-salting-out kettle, B120-salt feeding device and P107-vacuum pump.
Detailed Description
The invention is further explained with reference to the drawings and the embodiments.
Example 1
Referring to fig. 1-2, the cyclic manufacturing device for co-production of baking soda and ammonium chloride comprises a primary baking soda precipitation device 5, a cold precipitation device 6, a salting-out device 7, a mother liquor circulating device and a secondary baking soda precipitation device 8, wherein the primary baking soda precipitation device, the cold precipitation device 6, the salting-out device 7 and the mother liquor circulating device are sequentially communicated, one end of the secondary baking soda precipitation device 8 is communicated with the salting-out device 7, and the other end of the secondary baking soda precipitation device is communicated with the mother liquor circulating device.
Specifically, baking soda device 5 is appeared to one-level includes reation kettle L1101, brine groove T1102 and ammonium bicarbonate feeding device L1103 and reation kettle L1101 intercommunication.
Still be equipped with baking soda processing apparatus between baking soda device 5 and the cold separation device 6 is appeared to the one-level, baking soda processing apparatus includes solid-liquid separation equipment, drying device F109 and one-level liquid storage pot V106, solid-liquid separation equipment is arranged in with baking soda and the mother liquor separation that generate in reation kettle L1101, one-level liquid storage pot V106 is used for collecting baking soda mother liquor (I) after with baking soda separation, drying device F109 is used for the baking soda after dry and the mother liquor separation. Preferably, the solid-liquid separation device in this embodiment is a vacuum filter P104 and a centrifuge X108 which are sequentially communicated, the filter P104 is communicated with the primary liquid storage tank V106 through one end of a separation tank V105, and the other end of the separation tank V105 is connected with a vacuum pump P107.
Specifically, the cold separation device 6 is used for cold separation and crystallization of baking soda mother liquor (I) from the primary liquid storage tank V106, and comprises a crystallization kettle T1116, an external cooler P115 and an ice maker P113, wherein the crystallization kettle T1116 is communicated with the external cooler P115, and clear liquid at the upper end in the crystallization kettle T1116 is conveyed to the external cooler P115, cooled by the external cooler P115 and returned to the crystallization kettle T1116 for cold separation and crystallization; the external cooling P115 is in circulation communication with ice machine P113.
In this embodiment, the device further includes an ammonium chloride treatment device 9, and the ammonium chloride treatment device 9 is communicated with the cold separation device 6 and is used for filtering, dehydrating and drying the ammonium chloride separated out in the cold separation device 6.
The salting-out device 7 comprises a salting-out kettle T1118 and a salt feeding device B120, the salt feeding device B120 is communicated with the salting-out kettle T1118 and used for adding reaction salt into the salting-out kettle T1118, and the feeding end of the salting-out kettle T1118 is communicated with the cold separation device 6 and used for collecting overflow liquid discharged by the cold separation device 6 and carrying out salting-out crystallization on the overflow liquid.
Specifically, salting out cauldron T1118 includes clear liquid section 1, linkage segment 2 and suspension section 3, the height of suspension section 3 is 3m, clear liquid section 1 is equipped with the overflow mouth, the overflow mouth is linked together with second grade precipitation baking soda device 8, suspension section 3 is equipped with two brilliant paddles and takes out mouth 4, brilliant paddle takes out mouth 4 and sets up in distance suspension section top 3/4 department, brilliant paddle takes out mouth 4 and is linked together with the top of crystallization cauldron T1116.
Preferably, the included angle between the side edge of the connecting section 2 and the vertical direction is 60 degrees.
The secondary sodium bicarbonate precipitation device 8 comprises a concentration groove V121, a heating kettle L2121-1 and a centrifuge S122 which are communicated in sequence, wherein the concentration groove V121 is used for collecting sodium bicarbonate mother liquor (I-II) overflowed from the salting kettle T1118, and the heating kettle L2121-1 is used for heating the sodium bicarbonate mother liquor (I-II) to further precipitate sodium bicarbonate; the centrifuge S122 is used to separate the mother liquor from the baking soda further precipitated in the heating still L2121-1.
The mother liquor circulating device comprises a secondary liquid storage tank V125, and is used for collecting brine generated by the secondary sodium bicarbonate separating device 8 and the ammonium chloride treatment device 9, and returning supernatant liquid serving as sodium bicarbonate mother liquor (II) to the brine tank T1102 for recycling.
Specifically, a stirrer is arranged in the secondary liquid storage tank V125 at a position far from the bottom 1/4, and the bottom of the secondary liquid storage tank V125 is communicated with the heating kettle L2121-1 and used for returning and conveying the suspension liquid at the bottom in the secondary liquid storage tank V125 to the heating kettle L2121-1.
The recycling manufacturing device for the co-production of the baking soda and the ammonium chloride adopts the following specific operation processes:
directly adding 8.5 cubic meters of unpurified saturated brine into a reaction kettle L1101 with the capacity of 11 cubic meters through a brine tank T1102, heating to 35 ℃, adding 2200 kilograms of ammonium bicarbonate into the saturated brine through an ammonium bicarbonate feeding device L1103 ammonium bicarbonate metering belt to perform double decomposition reaction to generate sodium bicarbonate, filtering the sodium bicarbonate by using a vacuum filter X104, washing the sodium bicarbonate by using 100L of deionized water or saturated pure alkaline water at the temperature of 35 ℃, dehydrating by using a centrifugal machine X108, and drying by using a drying device F109 drying furnace to obtain the sodium bicarbonate;
collecting the baking soda mother liquor (I) after filtration and centrifuge dehydration to a primary liquid storage tank V106, directly conveying the baking soda mother liquor to a 9 cubic meter crystallization kettle T1116, simultaneously adding ammonium sulfate into the crystallization kettle T1116, circularly communicating the crystallization kettle with an ice maker P113 through an external cooler P115, controlling the temperature to be 15 ℃, freezing for 4 hours, and crystallizing and separating out ammonium chloride;
sodium bicarbonate mother liquor (I-I) after cold separation and crystallization overflows from a crystallization kettle T1116 to a salting-out kettle T1118, sodium chloride is added into the salting-out kettle T1118 through a salt feeding device B120 salt dosage belt, the temperature is controlled to be 20 ℃, ammonium chloride is further crystallized and precipitated and is precipitated to an outlet at the middle lower part of the salting-out kettle T1118, namely a crystal pulp taking-out port 4 of a suspension section 3, ammonium chloride crystal pulp is returned to the crystallization kettle T1116 through a pulp feeding pump P119 and is collected with ammonium chloride crystals frozen and precipitated in the crystallization kettle T1116, the ammonium chloride crystal pulp is conveyed to a low-level tank V117, and the ammonium chloride crystal pulp is filtered through a vacuum filter X124, dehydrated through a centrifuge X129 and packaged through a bag sewing machine K130 to obtain a finished product of ammonium chloride OK 131;
the supernatant in the salting-out kettle T1118 overflows to a thickening tank V121, flows to a heating kettle L2121-1 through the bottom of the thickening tank V121, baking soda is further separated out at the temperature of 35 ℃, the obtained baking soda is dehydrated by a centrifuge S122 and then is conveyed to a drying device F109 drying furnace for drying, and the dried baking soda is packaged by a bag sewing machine K110 to obtain a finished product baking soda OK 111;
and (3) collecting saturated brine generated in the ammonium chloride treatment device 9 and the secondary sodium bicarbonate precipitation device 8 into a secondary liquid storage tank V125, allowing the suspension to sink to the bottom under the action of stirring, returning to the heating kettle L2121-1, allowing the clear liquid to float upwards to serve as sodium bicarbonate mother liquor (II), heating to 35 ℃, returning to the reaction kettle L1101, performing double decomposition reaction with ammonium bicarbonate to produce sodium bicarbonate, repeatedly operating, recycling, and achieving the purpose of no wastewater discharge.
Specifically, the components in the baking soda mother liquor (I) in the circulating process are controlled to be NaCl 80g/L, NH 4 HCO 3120 g/L, NH 4 Cl 220g/L, SO 42-5 g/L; the content of the sodium bicarbonate mother liquor (II) is controlled to be 300g/L, NH 4 g/L, NH g/L, NH 4 Cl 50g/L, SO 42-5 g/L of NaCl. The yield of the soda produced by adopting the device is 98%, the yield of the ammonium chloride is 96%, and the content of nitrogen in the ammonium chloride product is 24%.
Specific example 2
This example differs from example 1 in that: the components in the mother liquid (I) of the baking soda during the circulation process are controlled to be NaCl 120g/L, NH 4 HCO 3100/3100 g/L, NH 4 Cl 200g/L, SO 42-8 g/L; the content of the sodium bicarbonate mother liquor (II) is controlled to be 230g/L, NH 4 g of NaCl, 370 g/L, NH 4 g of HCO, 120g/L, SO 42-8 g/L.
The yields of baking soda and ammonium chloride were calculated to be 96%, 95% and 24% respectively.
The working principle of the invention is as follows: the invention relates to a cyclic manufacturing method for preparing baking soda and co-producing ammonium chloride, which is based on a phase equilibrium principle and solubility, and the reason that a phase diagram in a system is difficult to balance is that anions of complex sodium and ammonium salt are univalent compounds, so that a molecular bonding chain is tightly buckled, the solubility product is not large in difference, and the potential difference is small.
The molecular adhesion of multi-element monovalent compounds can be broken by adding ammonium sulfate or ammonium carbonate as a divalent anion stimulant into the system, so that ammonium chloride crystals are separated out from the solution, and ammonium chloride or baking soda is obtained through separation, so that the balance of brine and ammonium brine is ensured.
In the cold separation crystallization stage, ammonium sulfate is added into a crystallization kettle, the crystallization of ammonium chloride is accelerated under the same ion effect and the acceleration effect of divalent anions, and compared with the direct freezing method, the ammonium chloride crystal can be separated out after being frozen for 8-10 h at the temperature of 5-10 ℃, the ammonium chloride crystal can be separated out only by freezing for 4h at the temperature of 15-20 ℃, the energy consumption for recovering ammonium chloride by cold separation crystallization is reduced, and the energy and the time are saved, and the economy is higher. In addition, due to precipitation of ammonium chloride crystals, the elutriation space of the baking soda mother liquor (I-I) after cold-precipitation crystallization is enlarged, the baking soda mother liquor (I-I) overflows to a salting-out kettle, sodium chloride is added into the salting-out kettle, the sodium chloride is quickly dissolved to occupy a water system, strong power of the same ions is generated, ammonium chloride crystallization is further promoted to be precipitated, the concentration of sodium ions in the solution is increased, and (NH 4) 2 SO 4 is converted into Na 2 SO 4, SO that the water system evolves saturated brine.
The existence of Na 2 SO 4 can quickly promote the bicarbonate radical to carry out double decomposition reaction with sodium chloride at low temperature to generate sodium bicarbonate and ammonium chloride, the ammonium chloride sinks to a crystal pulp outlet of a suspension section of the salting-out kettle, and the ammonium chloride crystal pulp is returned to the crystallization kettle through a pulp feeding pump, SO that the precipitation of the ammonium chloride can be further promoted through cold precipitation; on the other hand, ammonium chloride crystal nuclei are provided for the crystallization kettle, the growth of ammonium chloride crystals in the cold separation kettle is promoted, the ammonium chloride crystals are quickly separated out from the crystallization kettle, energy and time are saved, the sodium bicarbonate floats upwards into brine under the sublimation action of ammonia gas and carbon dioxide gas generated in the system conversion process and further overflows to the concentration tank, and is not eutectic with ammonium chloride, so that the quality of the ammonium chloride crystals is ensured, the sodium bicarbonate mixed into the brine flows to the heating kettle through the bottom of the concentration tank, is heated to 35 ℃, is secondarily separated out, and is dehydrated, washed and dried to obtain the qualified sodium bicarbonate.
The method comprises the steps of collecting brine generated in the ammonium chloride treatment process and the baking soda secondary precipitation process into a secondary liquid storage tank, allowing suspension to sink to the bottom under the action of stirring, returning to a heating kettle, allowing clear liquid to float upwards to serve as baking soda mother liquor (II), heating to 35 ℃, returning to a double decomposition reaction kettle, performing double decomposition reaction on the baking soda mother liquor and the ammonium bicarbonate to produce the baking soda, wherein due to the existence of Na 2 SO 4 in the baking soda mother liquor (II), baking soda crystal nuclei cannot be formed in the system to wrap ammonium bicarbonate particles which are not decomposed, SO that the ammonium bicarbonate decomposition rate is low, divalent anion sodium salt does not participate in the reaction, and is beneficial to slow precipitation and aggregation of the baking soda crystal nuclei to diffuse and deposit for growth, SO that ammonium bicarbonate solid does not be sealed and naturally participate in the reaction, and the decomposition rate is effectively promoted.
Claims (8)
1. A cyclic manufacturing method for co-production of baking soda and ammonium chloride comprises primary baking soda precipitation, cold precipitation crystallization, salting-out crystallization and mother liquor circulation which are sequentially carried out, and is characterized in that: the method also comprises a step of secondary sodium bicarbonate precipitation between the salting-out crystallization and the mother liquor circulation, which is used for further precipitating sodium bicarbonate from the sodium bicarbonate mother liquor (I-II) generated after the salting-out crystallization, and comprises the following specific steps:
(1) first-stage separation of sodium bicarbonate: adding saturated brine and ammonium bicarbonate into a reaction kettle for double decomposition reaction to generate sodium bicarbonate, filtering the obtained sodium bicarbonate, washing, dehydrating and drying;
(2) and (3) cold separation and crystallization: taking brine generated by the baking soda generated in the separation step (1) as baking soda mother liquor (I), conveying the baking soda mother liquor into a crystallization kettle, adding ammonium sulfate serving as a divalent anion accelerant into the crystallization kettle, controlling the temperature to be 15-20 ℃, freezing for 2.5-4 h, crystallizing and separating out ammonium chloride, and filtering and dehydrating the obtained ammonium chloride;
(3) salting out and crystallizing: overflowing sodium bicarbonate mother liquor (I-I) generated after cold separation crystallization from the crystallization kettle to a salting-out kettle, simultaneously adding sodium chloride into the salting-out kettle, controlling the temperature to be 20-25 ℃, further crystallizing and separating out ammonium chloride, settling to a crystal pulp outlet of the salting-out kettle, and returning ammonium chloride crystal pulp to the crystallization kettle in the step (2);
(4) and (3) secondary sodium bicarbonate precipitation: sodium bicarbonate mother liquor (I-II) generated after salting-out crystallization overflows to a thickening tank from a salting-out kettle, flows to a heating kettle through the bottom of the thickening tank, is separated out at the temperature of 35-45 ℃, and is dehydrated and dried;
(5) mother liquor circulation: and (3) collecting brine generated by separating ammonium chloride and brine generated by separating the baking soda in the second stage in the separation step (4) into a second-stage liquid storage tank, and returning supernatant in the second-stage liquid storage tank as baking soda mother liquor (II) to the step (1) for recycling.
2. The recycling manufacturing method of baking soda and ammonium chloride as well as the claim 1 is characterized in that: in the step (1), the washing process is to wash out chloride ions by adopting water or saturated pure alkaline water at the temperature of 35-45 ℃.
3. The recycling manufacturing method of baking soda and ammonium chloride as well as the claim 1 is characterized in that: and (5) arranging a stirrer in the position, away from the bottom 1/4-1/2, of the secondary liquid storage tank, wherein the bottom of the secondary liquid storage tank is communicated with the heating kettle, and the stirrer is used for returning the suspension at the bottom of the secondary liquid storage tank to the heating kettle to precipitate the baking soda again.
4. The recycling manufacturing method for co-production of baking soda and ammonium chloride according to any one of claims 1 to 3, characterized in that: the content of the sodium bicarbonate mother liquor (I) is controlled to be 80-120 g/L, NH of NaCl4HCO3 100~120g/L、NH4Cl 170~220g/L、SO4 2- 1~8g/L。
5. The recycling manufacturing method for co-production of baking soda and ammonium chloride according to any one of claims 1 to 3, characterized in that: the tasselThe component in the mother liquor (II) is controlled to be NaCl 210-300 g/L, NH4HCO3 50~70g/L、NH4Cl 50~80g/L、SO4 2- 1~8g/L。
6. The recycling manufacturing method for co-production of baking soda and ammonium chloride according to any one of claims 1 to 3, characterized in that: the device adopted by the method comprises a primary sodium bicarbonate precipitation device, a cold precipitation device, a salting-out device and a circulating device which are sequentially communicated, and a secondary sodium bicarbonate precipitation device, wherein one end of the secondary sodium bicarbonate precipitation device is communicated with the salting-out device, the other end of the secondary sodium bicarbonate precipitation device is communicated with the mother liquor circulating device, the salting-out device comprises a salting-out kettle and a salt feeding device, the salt feeding device is communicated with the salting-out kettle and used for adding reaction promoting salt into the salting-out kettle, and the feeding end of the salting-out kettle is communicated with the cold precipitation device and used for collecting overflow liquid discharged by the cold precipitation device and carrying out salting-out crystallization on the overflow liquid.
7. The recycling manufacturing method of baking soda and ammonium chloride as well as the manufacturing method of baking soda as claimed in claim 6 is characterized in that: the salting-out kettle comprises a clear liquid section, a connecting section and a suspension section, wherein the height of the suspension section is 1.5-3 m.
8. The recycling manufacturing method of baking soda and ammonium chloride as well as the claim 7 is characterized in that: the suspension section is provided with at least one crystal pulp taking-out opening, the crystal pulp taking-out opening is arranged at a position which is 1/2-3/4 away from the top end of the suspension section, and the crystal pulp taking-out opening is communicated with a bottom liquid pipe at the center of the top of the crystallization kettle.
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| CN112919502A (en) * | 2020-09-30 | 2021-06-08 | 湖南海联三一小苏打有限公司 | Process method for producing food-grade baking soda by double decomposition |
| CN112093812A (en) * | 2020-10-05 | 2020-12-18 | 湖南海联三一小苏打有限公司 | Cyclic manufacturing method for co-production of sodium bicarbonate and ammonium chloride |
| CN113184880A (en) * | 2021-04-21 | 2021-07-30 | 武汉工程大学 | Method for separating ammonium chloride and potassium chloride mixture based on three-stage crystallization |
| CN114132950B (en) * | 2021-11-30 | 2024-07-19 | 衡阳爱洁科技股份有限公司 | Method for preparing ammonium chloride by co-production of sodium bicarbonate |
| CN114014339B (en) * | 2021-11-30 | 2024-07-19 | 衡阳爱洁科技股份有限公司 | Method for preparing sodium bicarbonate with low ammonium salt content by co-producing sodium bicarbonate and ammonium chloride |
| CN115947350A (en) * | 2023-03-09 | 2023-04-11 | 北京赛科康仑环保科技有限公司 | Method for preparing sodium bicarbonate and ammonium chloride by using sodium chloride |
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