CN116477643A - Method for producing low-calcium salt from calcium sulfate type brine - Google Patents
Method for producing low-calcium salt from calcium sulfate type brine Download PDFInfo
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- CN116477643A CN116477643A CN202310548546.XA CN202310548546A CN116477643A CN 116477643 A CN116477643 A CN 116477643A CN 202310548546 A CN202310548546 A CN 202310548546A CN 116477643 A CN116477643 A CN 116477643A
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- calcium
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- mother liquor
- sulfate
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- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 title claims abstract description 71
- 239000012267 brine Substances 0.000 title claims abstract description 69
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 title claims abstract description 43
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 28
- 150000003839 salts Chemical class 0.000 claims abstract description 96
- 239000012452 mother liquor Substances 0.000 claims abstract description 60
- 239000011575 calcium Substances 0.000 claims abstract description 58
- 238000001704 evaporation Methods 0.000 claims abstract description 45
- 239000007788 liquid Substances 0.000 claims abstract description 45
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims abstract description 44
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 42
- 230000008020 evaporation Effects 0.000 claims abstract description 39
- 239000002002 slurry Substances 0.000 claims abstract description 37
- 159000000007 calcium salts Chemical class 0.000 claims abstract description 35
- 239000000047 product Substances 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 31
- 238000005406 washing Methods 0.000 claims abstract description 31
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 30
- 238000006243 chemical reaction Methods 0.000 claims abstract description 27
- 239000011777 magnesium Substances 0.000 claims abstract description 23
- 239000002244 precipitate Substances 0.000 claims abstract description 21
- 229910052602 gypsum Inorganic materials 0.000 claims abstract description 18
- 239000010440 gypsum Substances 0.000 claims abstract description 18
- 238000003825 pressing Methods 0.000 claims abstract description 18
- 239000002994 raw material Substances 0.000 claims abstract description 15
- 238000001035 drying Methods 0.000 claims abstract description 13
- 238000005086 pumping Methods 0.000 claims abstract description 11
- 239000003513 alkali Substances 0.000 claims abstract description 7
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 6
- 239000000126 substance Substances 0.000 claims abstract description 5
- 239000000706 filtrate Substances 0.000 claims abstract description 3
- 238000007599 discharging Methods 0.000 claims abstract 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 64
- 239000001110 calcium chloride Substances 0.000 claims description 41
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 41
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 230000001105 regulatory effect Effects 0.000 claims description 19
- 229910001424 calcium ion Inorganic materials 0.000 claims description 17
- 238000007738 vacuum evaporation Methods 0.000 claims description 17
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 claims description 14
- 229910001425 magnesium ion Inorganic materials 0.000 claims description 14
- KKCBUQHMOMHUOY-UHFFFAOYSA-N sodium oxide Chemical compound [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 14
- 229910001948 sodium oxide Inorganic materials 0.000 claims description 14
- 239000002351 wastewater Substances 0.000 claims description 14
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 13
- 229910052712 strontium Inorganic materials 0.000 claims description 12
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims description 12
- 229920005591 polysilicon Polymers 0.000 claims description 11
- 239000000243 solution Substances 0.000 claims description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 3
- 239000002585 base Substances 0.000 claims 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 abstract description 10
- 239000011780 sodium chloride Substances 0.000 abstract description 5
- 241001131796 Botaurus stellaris Species 0.000 abstract description 4
- 230000001276 controlling effect Effects 0.000 description 15
- 238000001514 detection method Methods 0.000 description 13
- 229910002651 NO3 Inorganic materials 0.000 description 12
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 11
- 239000012141 concentrate Substances 0.000 description 9
- 229910052736 halogen Inorganic materials 0.000 description 9
- 150000002367 halogens Chemical class 0.000 description 9
- 238000005259 measurement Methods 0.000 description 9
- 238000001914 filtration Methods 0.000 description 8
- 230000008901 benefit Effects 0.000 description 5
- 239000010413 mother solution Substances 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 4
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 3
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 3
- 229910052788 barium Inorganic materials 0.000 description 3
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000013049 sediment Substances 0.000 description 3
- 229910052938 sodium sulfate Inorganic materials 0.000 description 3
- 235000011152 sodium sulphate Nutrition 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Inorganic materials [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- ZFXVRMSLJDYJCH-UHFFFAOYSA-N calcium magnesium Chemical compound [Mg].[Ca] ZFXVRMSLJDYJCH-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000011085 pressure filtration Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/04—Chlorides
- C01D3/06—Preparation by working up brines; seawater or spent lyes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/14—Purification
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/14—Purification
- C01D3/16—Purification by precipitation or adsorption
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention relates to a method for producing low calcium salt by calcium sulfate type brine. The method takes gypsum type brine as a raw material, firstly removes the calcium and magnesium content in the brine to below 15mg/L by a two-alkali method, and then carries out filter pressing on a precipitate; pumping the clear liquid into an evaporation salt making device, evaporating and concentrating in vacuum at a certain temperature, discharging salt slurry, washing the salt slurry with refined brine, dehydrating and drying to prepare a low-calcium salt product; adding a calcium chloride solution into the evaporation mother liquor, reducing the sulfate radical concentration in the mother liquor, returning clear liquid to a pretreatment reaction tank after the reaction is finished, carrying out filter pressing on precipitate substances, and returning filtrate to a mother liquor tank. In the calcium sulfate type bittern, the qualified low-calcium sodium chloride product is extracted through a simple technological process.
Description
Technical Field
The invention belongs to the field of inorganic chemical industry, relates to a production method of low calcium salt, and in particular relates to a method for producing low calcium salt from calcium sulfate type brine.
Background
At present, lithium batteries are developed internationally at a high speed, the demands for lithium batteries are increased at home and abroad, but the special sodium carbonate for producing lithium carbonate has higher requirements for the quality of raw material salt, the current bittern production process cannot meet the requirements, and the gypsum type bittern is utilized to produce sodium carbonate in a salt-nitrate co-production mode in the market, but the method can increase the site, equipment and the like for producing the nitrate, and a large amount of investment is increased.
Disclosure of Invention
The invention aims to provide a method for producing low calcium salt by calcium sulfate type brine. In the method, refined halogen is obtained by adding sodium carbonate and caustic soda into raw halogen to remove impurities such as calcium, magnesium, etc., and the refined halogen is evaporated and concentrated to approach NaCl-Na 2 SO 4 And (3) at the saturation point, collecting crystalline salt, washing with refined brine, dehydrating and drying to obtain product salt, adding calcium chloride into salt-making mother liquor to precipitate sodium sulfate, and returning to a brine pretreatment system for recycling. The process is simple, and has great practical value for the place where the calcium chloride can be obtained at low cost.
In order to achieve the above object, the present invention has the following specific technical scheme:
a method for producing low calcium salt by calcium sulfate brine, which comprises the following steps:
taking gypsum type brine as a raw material, introducing the raw material into a pretreatment reaction tank, firstly removing the calcium and magnesium content in the brine to below 15mg/L by a two-alkali method, and then carrying out filter pressing on a precipitate; pumping the obtained clear liquid into an evaporation salt making device, and evaporating and concentrating in vacuum at a certain temperature to obtain salt slurry and evaporation mother liquor respectively; washing the salt slurry with refined brine, dehydrating and drying to obtain a low-calcium salt product; and adding a calcium chloride-containing solution into the evaporation mother liquor, reducing the sulfate radical concentration in the mother liquor, returning clear liquid to a pretreatment reaction tank after the reaction is finished, carrying out filter pressing on precipitate substances, returning filtrate to a mother liquor pool in which the evaporation mother liquor is stored, and carrying out landfill treatment on gypsum slag.
As a better implementation mode in the application, the two alkali in the two-alkali method is caustic soda or sodium carbonate; the specific steps of removing the calcium and magnesium content in the brine to below 15mg/L by the two-alkali method are as follows:
the gypsum type brine is firstly introduced with sodium carbonate for removing calcium, then the pH value of the brine is regulated by sodium oxide, clear liquid and sediment are separated by filter pressing after the reaction is finished, and filter residues after filter pressing are calcium-magnesium sludge which can be used as engineering landfill.
As a better implementation mode in the application, the addition amount of the sodium carbonate is carried out according to the molar ratio of calcium+strontium to sodium carbonate of 1:1.05-1.15; regulating the pH value of brine to 11.0-12.0 by sodium oxide; the two conditions are preferably such that the molar ratio of (calcium+strontium) to sodium carbonate is 1:1 and the pH is 12; the molar ratio of (calcium+strontium) to sodium carbonate is 1:1.05, and the pH is 12; the molar ratio of (calcium+strontium) to sodium carbonate is 1:1.1, and the pH is 11.5; the molar ratio of (calcium+strontium) to sodium carbonate is 1:1.1, and the pH is 12; the molar ratio of (calcium+strontium) to sodium carbonate is 1:1.15, and the pH is 11.5; the molar ratio of (calcium+strontium) to sodium carbonate was 1:1.15 and the pH was 12. More preferably, the addition of sodium carbonate is performed in a molar ratio of calcium+strontium to sodium carbonate of 1:1.1; the pH value of the brine is adjusted to 11.5 by sodium oxide.
Further, after the press filtration is finished, the pH of the clear liquid is reversely adjusted to 7.8-8.2.
As a preferred embodiment in the present application, the temperature of the vacuum evaporation concentration is 50-110 ℃, specifically 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃ and the like; the vacuum evaporation concentration multiple is 8-11 times, and can be specifically 8 times, 9 times, 10 times or 11 times, etc.
As a preferred embodiment in the present application, after the vacuum evaporation concentration is completed, the salt slurry is washed with refined brine, and the salt slurry is washed according to the washing water amount of V washing water: V salt slurry=1-2:1.
As a preferred embodiment in the application, the solution containing calcium chloride is a calcium chloride solution, polysilicon wastewater containing calcium chloride or a mixture of the two substances; in the solution containing calcium chloride, evaporating mother liquor is added with CaCl according to the mol ratio of sulfate radical to calcium chloride of 1:1.06-1.14 2 。
As a preferred embodiment in the present application, the low calcium salt product has a total calcium and magnesium ion content of less than 70ppm and a sulfate ion content of less than 0.30%.
Compared with the prior art, the invention has the beneficial effects that:
firstly, in calcium sulfate bittern, the qualified low-calcium sodium chloride product is extracted through a simple technological process.
The process can reduce the total calcium and magnesium ions in industrial wet salt and industrial dry salt to below 70ppm and reduce the sulfate ion content in salt to below 0.30%.
(III) the existing gypsum type brine salt making process is divided into 3 kinds: (1) salt-making-barium sulfate removal (2) salt-making-calcium sulfate removal (3) salt and nitrate co-production. The process avoids food safety accidents caused by extremely difficult control of the addition amount of barium in the sulfate radical removal process of the traditional process; the salt and nitrate co-production is avoided, although the salt and nitrate separation can be realized by utilizing the different solubilities of sodium chloride and sodium sulfate along with the temperature change, the nitrate evaporation equipment, the dehydration drying equipment, the packaging line and the like are required to be built, and the salt returning of the nitrate production mother solution can increase the difficulty and the benefit of the salt production operation; the calcium sulfate radical removal process can avoid food safety accidents to a great extent, does not need to additionally construct evaporation equipment and the like, is simple to operate, can reduce sulfate radical in salt to be less than 0.30 percent, and has the advantages of low cost, low cost and the likeIn Ca 2+ The method has great advantages in the place where the method can be obtained at low cost.
Description of the drawings:
fig. 1 is a schematic diagram of a process flow for producing low calcium salt from calcium sulfate brine according to the invention.
Detailed Description
In order that the invention may be more readily understood, a further description of the process according to the invention will be provided below with reference to the accompanying drawings and the detailed description. It should not be construed that the scope of the above subject matter of the present invention is limited to the following examples.
The gypsum type brine in the following examples is shown in Table 1 for reference.
TABLE 1 reference ingredients of raw materials
The following examples relate to the wash water as fine brine, the fine brine index being referred to in the following table:
| Ca | Mg | Cl | SO 4 2- |
| g/L | g/L | g/L | g/L |
| 0.010 | 0.004 | 168.4 | 3.87 |
in the application, the related proportion relation is mass ratio unless otherwise specified; % are mass percent.
Example 1:
gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate with a molar ratio of 1:1.10, regulating the pH of brine to 11.0 by using sodium oxide, separating clear liquid from precipitate by pressure filtration after the reaction is finished, reversely regulating the pH of the clear liquid to 7.8, pumping the clear liquid into an evaporation tank, controlling the evaporation temperature to 55 ℃, controlling the vacuum evaporation concentration multiple to be 8 times, washing the salt slurry according to the washing water amount of V (washing water): V (salt slurry) to be 2:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low calcium salt product, and obtaining mother liquor according to sulfate radicals: adding CaCl with the molar ratio of calcium chloride being 1:1.06 2 Separating the precipitate from the clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to the raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The results of the detection of the content of (C) are shown in Table 2-1, and CaCl is also measured 2 SO in the mother liquor after treatment 4 2- The content was measured, and the measurement results are shown in Table 2-2. The results of the data in tables 2-1 and 2-2 show that the sum of calcium and magnesium ions in the industrial dry salt and wet salt is below 70ppm, and SO is contained in the treated mother liquor 4 2- The content is 4.83g/L, which is close to 4.12g/L in the raw brine, and the salt product and the mother liquor reach the expected indexes.
TABLE 2-1 Low calcium salt data detection
TABLE 2-2 calcium chloride treatment mother liquor
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 1:1.06 | 1.26 | 0 | 4.83 | 188 |
Comparison of traditional salt products with the present Process index
The comparison between the traditional salt product and the technological index shows that the technological process can reduce the total calcium and magnesium ion content in wet industrial salt and dry industrial salt to below 70ppm and the sulfate ion content in salt to below 0.30%. The existing gypsum type brine salt making process is divided into 3 kinds: (1) salt-making-barium sulfate removal (2) salt-making-calcium sulfate removal (3) salt and nitrate co-production. In the process of removing sulfate radical by barium, the adding amount of barium is extremely difficult to control, and food safety accidents are easy to cause; salt and nitrate co-production can realize salt and nitrate separation by utilizing the different solubilities of sodium chloride and sodium sulfate along with the temperature change, but the construction of a nitrate evaporation device, a dehydration drying device, a packaging line and the like are required, and the salt recovery of the nitrate production mother solution can increase the difficulty and the benefit of salt production operation; the calcium sulfate radical removal process can avoid food safety accidents to a great extent, meanwhile, no additional evaporation equipment and the like are needed, the operation is simple, sulfate radical in salt can be reduced to below 0.30%, and the method has great advantages for the place where Ca2+ can be obtained at low cost.
Example 2
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate in a molar ratio of 1:1.10, regulating the pH of brine to 11.5 by using sodium oxide, separating clear liquid from precipitate by press filtration after the reaction is finished, reversely regulating the pH of the clear liquid to 8.0, pumping into an evaporation tank, controlling the evaporation temperature to 75 ℃, controlling the vacuum evaporation concentration multiple to be 10 times, washing the salt slurry according to the washing water volume of V (washing water): V (salt slurry) to be 1:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low-calcium salt product, and obtaining mother liquor according to sulfate radicals: adding CaCl with the molar ratio of calcium chloride being 1:1.1 2 Separating the precipitate from the clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to the raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The results of the detection of the content of (C) are shown in Table 3-1, and CaCl is also measured 2 SO in the mother liquor after treatment 4 2- The content was measured, and the measurement results are shown in Table 3-2. As a result of the data in tables 3-1 and 3-2, the total of calcium and magnesium ions in the industrial dry salt and wet salt was 65ppm or less, and SO was contained in the mother liquor after treatment 4 2- The content is 4.17g/L, which is close to 4.12g/L in the raw brine, and the salt product and the mother liquor reach the expected indexes.
TABLE 3-1 Low calcium salt data detection
TABLE 3-2 calcium chloride treatment mother liquor
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 1:1.1 | 1.51 | 0 | 4.17 | 189 |
Example 3
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate in a molar ratio of 1:1.10, regulating the pH value of brine to 12.0 by using sodium oxide, separating clear liquid from precipitate by press filtration after the reaction is finished, reversely regulating the pH value of the clear liquid to 8.2, pumping the clear liquid into an evaporation tank, controlling the evaporation temperature to 95 ℃, controlling the vacuum evaporation concentration multiple to 11 times, washing the salt slurry according to the washing water amount of V (washing water): V (salt slurry) to 1:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low-calcium salt product, and obtaining mother liquor according to sulfate radicals: adding CaCl with the molar ratio of calcium chloride being 1:1.14 2 Separating the precipitate from the clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to the raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The results of the detection of the content of (C) are shown in Table 4-1, and CaCl is also measured 2 SO in the mother liquor after treatment 4 2- The content was measured, and the measurement results are shown in Table 4-2. Industrial dry salt was obtained from the data in tables 4-1 and 4-2The sum of calcium and magnesium ions in the wet salt is below 61ppm, and SO in the mother solution after treatment 4 2- The content of Ca is 3.87g/L, which is slightly lower than the content of 4.12g/L in the raw halogen 2+ The content of the salt is 1.71g/L which is slightly higher than the content of 1.57g/L in the raw brine, and both the salt and the mother liquor reach the expected indexes. The main composition table of the polysilicon wastewater concentrate is shown in the following table:
main ingredient table of polysilicon wastewater concentrate
| CaCl 2 | NaCl |
| ％ | ％ |
| 40 | 3 |
TABLE 4-1 Low calcium salt data detection
TABLE 4-2 calcium chloride treatment mother liquor
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 1:1.14 | 1.71 | 0 | 3.87 | 189 |
Example 4
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate in a molar ratio of 1:1.10, regulating the pH of brine to 11.5 by using sodium oxide, separating clear liquid from precipitate by press filtration after the reaction is finished, reversely regulating the pH of the clear liquid to 8.0, pumping into an evaporation tank, controlling the evaporation temperature to 95 ℃, controlling the vacuum evaporation concentration multiple to be 10 times, washing the salt slurry according to the washing water volume of V (washing water): V (salt slurry) to be 1:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low-calcium salt product, and obtaining mother liquor according to sulfate radicals: adding the polycrystalline silicon wastewater concentrated solution into the mixture according to the molar ratio of calcium chloride of 1:1.14, separating sediment from clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to a raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The content of the wastewater is detected as shown in the table 5-1, and SO in the mother solution treated by the polysilicon wastewater concentrate 4 2- The content was measured, and the measurement results are shown in Table 5-2. As a result of the data in tables 5-1 and 5-2, the total of calcium and magnesium ions in the industrial dry salt and wet salt was 58ppm or less, and SO was contained in the mother liquor after treatment 4 2- The content of Ca is 3.85g/L, which is slightly lower than the content of 4.12g/L in the raw halogen 2+ The content of the salt is 1.70g/L which is slightly higher than the content of 1.57g/L in the raw brine, and both the salt and the mother liquor reach the expected indexes.
TABLE 5-1 Low calcium salt data detection
TABLE 5-2 mother liquor for treating polysilicon concentrate
Example 5
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate in a molar ratio of 1:1.10, regulating the pH of brine to 11.5 by using sodium oxide, separating clear liquid from precipitate by press filtration after the reaction is finished, reversely regulating the pH of the clear liquid to 8.0, pumping into an evaporation tank, controlling the evaporation temperature to 75 ℃, controlling the vacuum evaporation concentration multiple to be 10 times, washing the salt slurry according to the washing water volume of V (washing water): V (salt slurry) to be 1:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low-calcium salt product, and obtaining mother liquor according to sulfate radicals: adding the polycrystalline silicon wastewater concentrated solution into the mixture according to the molar ratio of calcium chloride of 1:1.1, separating sediment from clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to a raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The content of the wastewater is detected as shown in the table 6-1, and SO in the mother solution treated by the polysilicon wastewater concentrate 4 2- The content was measured, and the measurement results are shown in Table 6-2. According to the data in tables 6-1 and 6-2, the sum of calcium and magnesium ions in the industrial dry salt and wet salt is below 66ppm, and SO is contained in the mother liquor after treatment 4 2- The content is 4.13g/L, which is close to 4.12g/L in the raw brine, and the salt product and the mother liquor reach the expected indexes.
TABLE 6-1 Low calcium salt data detection
TABLE 6-2 mother liquor for treating polysilicon concentrate
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 1:1.1 | 1.52 | 0 | 4.13 | 189 |
Comparative example 1
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate in a molar ratio of 1:1.05, regulating the pH of brine to 11.5 by using sodium oxide, separating clear liquid from precipitate by press filtration after the reaction is finished, reversely regulating the pH of the clear liquid to 8.0, pumping into an evaporation tank, controlling the evaporation temperature to 75 ℃, controlling the vacuum evaporation concentration multiple to be 10 times, washing the salt slurry according to the washing water volume of V (washing water): V (salt slurry) to be 1:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low-calcium salt product, and obtaining mother liquor according to sulfate radicals: adding CaCl with the molar ratio of calcium chloride being 1:1.0 2 Separating the precipitate from the clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to the raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The results of the measurement of the content of (C) are shown in Table 7-1, and CaCl is also measured 2 SO in the mother liquor after treatment 4 2- The content was measured, and the measurement results are shown in Table 7-2. As a result of the data in tables 7-1 and 7-2, the sum of calcium and magnesium ions in the industrial dry salt and wet salt was higher than 120ppm, and SO was contained in the mother liquor after treatment 4 2- The content of Ca is 6.11g/L, which is far higher than the content of 4.12g/L in the raw halogen 2+ The content of the salt is 0.99g/L which is slightly lower than the content of 1.57g/L in the raw halogen, and the salt and the mother liquor do not reach the expected indexes.
TABLE 7-1 Low calcium salt data detection
TABLE 7-2 calcium chloride treatment mother liquor
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
Comparative example 2
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate at molar ratio of 1:1.05, regulating pH of brine to 10.5 with sodium oxide, separating clear liquid from precipitate by press filtration after reaction, reversely regulating pH of clear liquid to 8.2, pumping into evaporating pot, and controlling evaporating temperature to 75deg.CThe air evaporation concentration multiple is 7.0 times, after evaporation, the salt slurry is washed according to the washing water volume of V (washing water) with V (salt slurry) being 1:1, the washed salt slurry is dried and dehydrated to obtain a low calcium salt product, and the mother liquor is prepared according to sulfate radical: adding CaCl with the molar ratio of calcium chloride being 1:1.05 2 Separating the precipitate from the clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to the raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The results of the detection of the content of (C) are shown in Table 8-1, and CaCl is also measured 2 SO in the mother liquor after treatment 4 2- The content was measured, and the measurement results are shown in Table 8-2. As a result of the data in tables 8-1 and 8-2, the sum of calcium and magnesium ions in both the industrial dry salt and wet salt was less than 120ppm, but SO was contained in the treated mother liquor 4 2- The content of Ca is 2.11g/L, which is lower than the content of 4.12g/L in the raw halogen 2+ The content of 0.73g/L is lower than the content of 1.57g/L in the raw brine, and the calcium and magnesium ions in the salt product reach the expected standard, but the mother liquor does not reach the expected index.
TABLE 8-1 Low calcium salt data detection
TABLE 8-2 calcium chloride treatment mother liquor
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 1:1.05 | 0.73 | 0 | 2.11 | 186.7 |
Comparative example 3
Gypsum type brine is prepared according to the following steps: removing calcium from sodium carbonate in a molar ratio of 1:1.05, regulating the pH of brine to 10.5 by using sodium oxide, separating clear liquid from precipitate by press filtration after the reaction is finished, reversely regulating the pH of the clear liquid to 8.2, pumping into an evaporation tank, controlling the evaporation temperature to 75 ℃, controlling the vacuum evaporation concentration multiple to be 12.0 times, washing the salt slurry according to the washing water amount of V (washing water): V (salt slurry) to be 1:1 after the evaporation is finished, drying and dehydrating the washed salt slurry to obtain a low-calcium salt product, and obtaining mother liquor according to sulfate radicals: adding CaCl with the molar ratio of calcium chloride being 1:1.05 2 Separating the precipitate from the clear liquid through filter pressing after the reaction is finished, and returning the clear liquid to the raw material pool; finally, ca in the low calcium salt product 2+ ,Mg 2+ ，SO 4 2- Cl - The results of the detection of the content of (C) are shown in Table 9-1, and CaCl is also measured 2 SO in the mother liquor after treatment 4 2- The content was measured, and the measurement results are shown in Table 9-2. As a result of the data in tables 9-1 and 9-2, the sum of calcium and magnesium ions in both the industrial dry salt and wet salt was less than 120ppm, but SO was contained in the treated mother liquor 4 2- The content is 5.23g/L, which is higher than the content of 4.12g/L in the raw halogen, ca 2+ The content of 2.11g/L is higher than the content of 1.57g/L in the raw brine, and the calcium and magnesium ions in the salt product reach the expected standard, but the mother liquor does not reach the expected index.
TABLE 9-1 Low calcium salt data detection
TABLE 9-2 calcium chloride treatment mother liquor
| Sulfate radical: molar ratio of calcium chloride | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 1:1.05 | 2.11 | 0 | 5.23 | 186.7 |
Experiment 1:
the operation was performed on the basis of example 1, except that the molar ratio of (calcium+strontium) to sodium carbonate was different in the brine pretreatment process, and the other steps were the same in parameters, with the following specific results:
table 10 pretreatment of brine
According to the data in table 10, preliminary screening (calcium+strontium): the molar ratio of sodium carbonate is 1:1, the pH is 12, 1:1.05, the pH is 12, 1:1.1, the pH is 11.5, 1:1.1, the pH is 12, 1:1.15, the pH is 11.5, 1:1.15, the pH is 12, and six conditions are comprehensively considered, investment in equipment and materials is integrated, and the optimal hardness reducing treatment conditions are selected, wherein the molar ratio of sodium carbonate is 1:1.1 and the pH is 11.5.
Experiment 2:
the procedure is based on example 1, and the mother liquor composition difference under different vacuum evaporation concentration factors is determined to be different from the wet salt composition difference under different concentration factors, and the specific table is as follows:
TABLE 11 Table of wet salt compositions at different concentration factors
As can be seen from Table 11, the salt components are different from each other in different vacuum evaporation concentration factors, and when the evaporation concentration factor is less than or equal to 11, the produced salt product meets the quality standard. ( And (3) injection: in order to improve the salt yield and reduce the cost in production, the concentration multiple is generally improved as much as possible on the premise of reaching the salt quality. )
Experiment 3:
experiments were performed on the basis of example 1, with the only difference that the mother liquor was treated with 40% by mass calcium chloride (see table 12-1) or with the mother liquor was treated with polysilicon wastewater concentrate (see table 12-2), and the experimental results of the treatment of the mother liquor were determined for different calcium chloride addition amounts, specifically as shown in the following table:
TABLE 12 Experimental results of 40% calcium chloride treatment mother liquor
| Calcium chloride addition | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 90％ | 0.73 | 0 | 9.34 | 189.6 |
| 95％ | 0.81 | 0 | 7.60 | 190 |
| 100％ | 0.99 | 0 | 6.11 | 191 |
| 105％ | 1.25 | 0 | 5.03 | 188 |
| 110％ | 1.51 | 0 | 4.17 | 189 |
| 114％ | 1.71 | 0 | 3.87 | 189 |
| 118％ | 1.83 | 0 | 3.21 | 189.5 |
As shown in the data in Table 12-1, as the concentration of calcium ions in the solution increases, the sulfate gradually decreases, and the addition of calcium chloride effectively removes the sulfate in the mother liquor. When the addition amount of calcium chloride reaches 110% of the theoretical reaction amount, the calcium ions and sulfate radical in the clear liquid after mother liquid treatment are close to the raw water, so 110% is selected as the experimental condition for sulfate radical removal.
TABLE 12-2 Experimental results on polysilicon wastewater concentrate
| Waste water addition amount | Ca 2+ (g/L) | Mg 2+ (g/L) | SO 4 2- (g/L) | Cl - (g/L) |
| 90％ | 0.75 | 0 | 9.55 | 189.9 |
| 95％ | 0.80 | 0 | 7.57 | 190.3 |
| 100％ | 0.95 | 0 | 6.02 | 190.5 |
| 105％ | 1.20 | 0 | 5.42 | 189.4 |
| 110％ | 1.48 | 0 | 4.09 | 189.8 |
| 114％ | 1.77 | 0 | 3.83 | 189.6 |
| 118％ | 1.82 | 0 | 3.23 | 189.2 |
The data in Table 12-2 shows that the experimental effect of the polysilicon wastewater concentrate is substantially no different from the experimental effect of the 40% calcium chloride treatment mother liquor.
Finally, it is noted that the above-mentioned preferred embodiments are only intended to illustrate rather than limit the invention, and that, although the invention has been described in detail by means of the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.
Claims (10)
1. The method for producing the low-calcium salt by using the calcium sulfate brine is characterized by comprising the following steps of:
taking gypsum type brine as a raw material, introducing the raw material into a pretreatment reaction tank, firstly removing the calcium and magnesium content in the brine to below 15mg/L by a two-alkali method, and then carrying out filter pressing on a precipitate; pumping the clear liquid obtained by filter pressing into an evaporation salt making device, evaporating and concentrating in vacuum at a certain temperature, discharging salt slurry, washing the salt slurry with refined brine, dehydrating and drying to obtain a low-calcium salt product; and (3) adding a solution containing calcium chloride into the evaporation mother liquor obtained in the vacuum evaporation concentration step, reducing the sulfate radical concentration in the mother liquor, returning clear liquid to a pretreatment reaction tank after the reaction is finished, carrying out filter pressing on precipitate substances, and returning filtrate to an evaporation mother liquor tank.
2. The method for producing low calcium salt from calcium sulfate type brine according to claim 1, wherein the two bases in the two-base method are caustic soda and sodium carbonate; the specific steps of removing the calcium and magnesium content in the brine to below 15mg/L by the two-alkali method are as follows: and (3) introducing sodium carbonate into gypsum type brine to remove calcium, regulating the pH of the brine by using sodium oxide, and separating clear liquid from precipitate by filter pressing after the reaction is finished.
3. The method for producing low calcium salt from calcium sulfate brine according to claim 1, wherein the vacuum evaporation concentration temperature is 50-110 ℃ and the vacuum evaporation concentration multiple is 8-11 times.
4. The method for producing low calcium salt from calcium sulfate brine according to claim 1, wherein after the vacuum evaporation concentration is finished, the salt slurry is washed with refined brine, and the salt slurry is washed according to the washing water amount of V washing water to V salt slurry=1-2:1.
5. The method for producing low calcium salt from calcium sulfate type brine according to claim 1, wherein the solution containing calcium chloride is added into the evaporation mother liquor obtained in the vacuum evaporation concentration step to reduce the sulfate concentration in the mother liquor, and the addition amount of the solution containing calcium chloride is calculated according to the molar ratio of sulfate to calcium chloride in the evaporation mother liquor=1:1.06-1.14.
6. The method for producing low calcium salt from calcium sulfate brine according to claim 1 or 5, wherein the solution containing calcium chloride is a calcium chloride solution, a calcium chloride-containing polysilicon wastewater or a mixture of both.
7. The method for producing low calcium salt from calcium sulfate brine according to claim 1 or 4, wherein the salt slurry is washed with fine brine for 1 time.
8. The method for producing low calcium salt from calcium sulfate brine according to claim 1, wherein the addition of sodium carbonate is performed according to a molar ratio of calcium+strontium to sodium carbonate of 1:1.05-1.15; the pH value of the brine is adjusted to 11.0-12.0 by sodium oxide.
9. The method for producing low calcium salt from calcium sulfate brine according to claim 8, wherein the addition of sodium carbonate is performed according to a molar ratio of calcium+strontium to sodium carbonate of 1:1.1; the pH value of the brine is adjusted to 11.5 by sodium oxide.
10. The method for producing low calcium salt from calcium sulfate type brine according to claim 1, wherein the total amount of calcium and magnesium ions in the low calcium salt product is reduced to less than 70ppm, and the sulfate ion content is reduced to less than 0.30%.
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| CN103964472A (en) * | 2014-05-26 | 2014-08-06 | 江苏井神盐化股份有限公司 | Method for producing refined moisture diffusion industrial salt based on underground recycling of waste liquid |
| CN103979579A (en) * | 2014-05-26 | 2014-08-13 | 江苏井神盐化股份有限公司 | Method for preparing refined salt low in calcium and magnesium by utilizing underground denitration process |
| CN104891531A (en) * | 2015-05-13 | 2015-09-09 | 中盐舞阳盐化有限公司 | Preparation method of metal sodium salt |
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