CN110790685A - Method for producing urea phosphate by wet-process phosphoric acid reduced pressure evaporation coupled elution crystallization - Google Patents
Method for producing urea phosphate by wet-process phosphoric acid reduced pressure evaporation coupled elution crystallization Download PDFInfo
- Publication number
- CN110790685A CN110790685A CN201911249572.2A CN201911249572A CN110790685A CN 110790685 A CN110790685 A CN 110790685A CN 201911249572 A CN201911249572 A CN 201911249572A CN 110790685 A CN110790685 A CN 110790685A
- Authority
- CN
- China
- Prior art keywords
- crystallization
- urea phosphate
- phosphoric acid
- wet
- acetone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000002425 crystallisation Methods 0.000 title claims abstract description 98
- 230000008025 crystallization Effects 0.000 title claims abstract description 96
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 84
- DZHMRSPXDUUJER-UHFFFAOYSA-N [amino(hydroxy)methylidene]azanium;dihydrogen phosphate Chemical compound NC(N)=O.OP(O)(O)=O DZHMRSPXDUUJER-UHFFFAOYSA-N 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 51
- 238000001704 evaporation Methods 0.000 title claims abstract description 48
- 230000008020 evaporation Effects 0.000 title claims abstract description 44
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 41
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 22
- 238000010828 elution Methods 0.000 title claims abstract description 14
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims abstract description 72
- 239000012452 mother liquor Substances 0.000 claims abstract description 21
- 239000007788 liquid Substances 0.000 claims abstract description 14
- 238000000605 extraction Methods 0.000 claims abstract description 11
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000004202 carbamide Substances 0.000 claims abstract description 10
- 239000013078 crystal Substances 0.000 claims abstract description 10
- 230000006837 decompression Effects 0.000 claims abstract description 9
- 238000003756 stirring Methods 0.000 claims abstract description 7
- 238000001035 drying Methods 0.000 claims abstract description 4
- 239000012065 filter cake Substances 0.000 claims abstract description 4
- 238000000926 separation method Methods 0.000 claims abstract description 4
- 238000005406 washing Methods 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 12
- 239000007791 liquid phase Substances 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 229910019142 PO4 Inorganic materials 0.000 claims description 4
- 238000012840 feeding operation Methods 0.000 claims description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 3
- 239000010452 phosphate Substances 0.000 claims description 3
- 239000002002 slurry Substances 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 3
- 230000008569 process Effects 0.000 abstract description 11
- 238000005265 energy consumption Methods 0.000 abstract description 8
- 239000000047 product Substances 0.000 abstract description 8
- 238000001816 cooling Methods 0.000 abstract description 7
- 239000002994 raw material Substances 0.000 abstract description 7
- 230000007547 defect Effects 0.000 abstract description 3
- 230000002776 aggregation Effects 0.000 abstract description 2
- 238000004220 aggregation Methods 0.000 abstract description 2
- 239000000725 suspension Substances 0.000 abstract description 2
- 238000004904 shortening Methods 0.000 abstract 1
- 239000012535 impurity Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 241001465754 Metazoa Species 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 241000219000 Populus Species 0.000 description 1
- 241000282849 Ruminantia Species 0.000 description 1
- 238000009388 chemical precipitation Methods 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 229910017053 inorganic salt Inorganic materials 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
- C07C273/14—Separation; Purification; Stabilisation; Use of additives
- C07C273/16—Separation; Purification
Abstract
The invention relates to a method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization. The technical scheme is as follows: adding wet-process phosphoric acid, urea and acetone into a crystallization kettle, and stirring at constant temperature for 0.5-1 h to prepare urea phosphate crystallization mother liquor; and evaporating urea phosphate crystallization mother liquor under 0-101.3 kPa, continuously feeding acetone into the urea phosphate crystallization mother liquor, controlling the extraction rate of the evaporation condensate in the crystallization kettle to be 1-20 mL/min, controlling the volume feeding rate of the acetone to be 1-5 times of the extraction rate of the condensate, carrying out solid-liquid separation after crystallization is finished, and washing and drying a filter cake to obtain urea phosphate crystals. The method has the advantages of obviously reducing the operation energy consumption of producing the urea phosphate by taking wet-process phosphoric acid as a raw material, shortening the production period and improving the crystallization yield and purity, avoids the defect of continuously increasing the suspension density of the crystallization mother liquor in the process of evaporative crystallization or cooling crystallization, and can effectively reduce the phenomena of crushing and aggregation of the crystallized product.
Description
Technical Field
The invention belongs to the technical field of phosphorus chemical production, and particularly relates to a method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization.
Background
Urea phosphate (urea phosphate) is a fine chemical product widely applied to the fields of animal husbandry, industry, agriculture and the like, is not only a type I additive legally prescribed by the European Union feed industry, but also a special nutrient additive for ruminants and a phosphorus supplement recommended by the food and agricultural organization of the United nations in the animal husbandry, and has wide market prospect and great potential. The urea phosphate is a complex compound obtained by equivalent reaction of phosphoric acid and urea, and has a chemical formula of CO (NH)2)2–H3PO4At present, wet-process phosphoric acid is mostly used as a raw material to synthesize urea phosphate abroad, and the mainstream process comprises a two-stage method (a U.S. TVA method), a secondary crystallization method and a concentration crystallization method; most of the domestic uses hot phosphoric acid as raw material to synthesize urea phosphate. However, the thermal phosphoric acid process has high energy consumption, which causes the production cost to be overhigh, thereby limiting the market competitiveness of the urea phosphate in China. In recent years, with the improvement of purification and concentration technologies of wet-process phosphoric acid, many manufacturers gradually turn to the production of urea phosphate products by using wet-process phosphoric acid as a raw material, namely, the urea phosphate is prepared by pretreating the wet-process phosphoric acid through purification (solvent extraction or chemical precipitation), and then carrying out reaction and crystallization.
However, wet process phosphoric acid, although lower in cost, has P as compared to hot process phosphoric acid2O5The content is low, the impurity content is high, and the operations of purifying, removing impurities, concentrating and the like are often carried out before the urea phosphate is prepared, so that the production process is more complicated, and the energy consumption is high.
The existing urea phosphate crystallization process mainly comprises cooling crystallization and evaporative crystallization. The cooling crystallization process of urea phosphate mostly adopts intermittent operation, and the cooling crystallization process of urea phosphate taking wet-process phosphoric acid as a raw material mostly needs concentration operation; in actual production, the urea phosphate crystals scale on the wall of the heat exchanger seriously, so that the heat exchange efficiency is reduced, the production period is prolonged, the yield is reduced, and the cost is increased. Because the urea phosphate has higher solubility in the aqueous solution, the utilization rate of P, N in the raw material wet-process phosphoric acid and urea is lower. Because the specific heat and the evaporation latent heat of water are larger, and the solubility of the urea phosphate in the aqueous solution is larger, the viscosity and the concentration of the urea phosphate evaporation crystallization liquid are higher, so that the energy consumption of the urea phosphate evaporation crystallization operation is higher, and although the evaporation operation temperature can be properly reduced by adopting the pressure reduction operation, the comprehensive production cost is still higher.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization.
In order to achieve the purpose, the technical scheme adopted by the invention is specifically completed according to the following steps:
step one, adding wet-process phosphoric acid, urea and acetone into a crystallization kettle under the conditions of normal pressure, 60-70 ℃ and 50-300 r/min of rotating speed, and stirring at constant temperature for 0.5-1 h to prepare urea phosphate crystallization mother liquor, wherein the mass of added urea is P contained in wet-process phosphoric acid in the crystallization kettle2O50.85-0.9 times of the mass, and the adding volume of the acetone is equal to the H contained in the wet-process phosphoric acid in the crystallization kettle20.2-2.0 times of the volume of O;
and step two, evaporating the urea phosphate crystallization mother liquor prepared in the step one at the temperature of 60-70 ℃ and the rotating speed of 50-300 r/min, continuously feeding acetone into the urea phosphate crystallization mother liquor, controlling the extraction rate of evaporation condensate in a crystallization kettle to be V mL/min, the volume feeding rate of the acetone to be (1-5) V mL/min, and when the volume ratio of the acetone to water in the liquid phase in the crystallization kettle is (2.5-10): 1, synchronously stopping evaporation and acetone feeding operation, then leading out crystal slurry in a crystallization kettle for solid-liquid separation, washing and drying a filter cake to obtain urea phosphate crystals;
v is a real number which is more than or equal to 1 and less than or equal to 20;
the control of the extraction rate of the evaporation condensate in the crystallization kettle is V mL/min, which means that the volume of liquid extracted from the steam condensate in the crystallization kettle in unit time (min) is V mL, if the volume of the steam condensate generated in the crystallization kettle in unit time (min) is more than V mL, the extraction rate of the evaporation condensate is still V mL/min, and the rest condensate flows back into the crystallization kettle;
the acetone is fed into the urea phosphate crystallization mother liquor, namely the feeding port of the acetone is positioned below the liquid level of the urea phosphate crystallization mother liquor.
The crystallization kettle is a jacket stirring reaction kettle with controllable temperature.
The wet-process phosphoric acid is prepared by decomposing phosphate ore by adopting concentrated sulfuric acid, wherein P is2O5The content is 20 to 50 wt%.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following positive effects:
(1) the existing urea phosphate production process taking wet-process phosphoric acid as a raw material mostly adopts evaporation concentration and then cooling crystallization, and the water amount required to be evaporated is large and the energy consumption is high. The invention relates to a method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupling elution crystallization, which couples three operations of evaporation concentration, evaporation crystallization and elution crystallization together and synchronously carries out the three operations. In addition, the low-boiling point acetone solvent (normal pressure boiling point 56 ℃) is added before evaporation, and acetone is supplemented to the evaporation liquid phase during evaporation, so that the operation temperature of evaporation concentration and evaporation crystallization can be effectively reduced; and then, by combining with the pressure reduction operation, the operation temperature of the liquid in the crystallization kettle is further controlled to be 60-70 ℃, because the operation temperature is lower than 60 ℃, the conversion rate of phosphoric acid and urea for reaction to generate urea phosphate is low, the yield of the urea phosphate is low, and the operation temperature is higher than 70 ℃, the increase trend of the yield of the urea phosphate is remarkably slowed down, and the energy consumption is increased. The acetone dissolving out agent with volatility greater than that of water is continuously added in the evaporation concentration and evaporation crystallization processes, and the water evaporation rate of unit energy consumption can be increased, so that the method can obviously reduce the operation energy consumption and shorten the production period.
(2) The method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization avoids the defect that the suspension density of crystallization mother liquor is continuously increased in the evaporation crystallization or cooling crystallization process, and the continuous addition of the acetone elutriation agent and the addition rate of acetone are greater than the extraction rate of evaporation condensate, so that the volume of a liquid phase in a crystallization kettle is continuously increased, the phenomena of crushing and aggregation of crystal products can be greatly reduced, and the concentration of the particle size distribution of the products is facilitated.
(3) Urea phosphate has a greater solubility in water (76.4 wt% at 60 ℃; 49.2 wt% at 15 ℃) [ poplar sails, field-opening, liufei ] solubility in water as determined by the laser method [ J ] inorganic salt industry 2016,48(4):69-71 ], whereas solubility in acetone is small (less than 0.01g/mL acetone). The traditional urea phosphate evaporation crystallization and cooling crystallization processes both adopt water as a solvent, and a large amount of urea phosphate crystals are not crystallized and separated out in mother liquor when the crystallization is finished, so that the product yield is low. The method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization has the advantages that the liquid phase contains a large amount of acetone and a small amount of water when the crystallization operation is finished, and the product yield of urea phosphate can be obviously improved.
(4) According to the method for producing urea phosphate by wet-process phosphoric acid through reduced pressure evaporation coupled elution crystallization, the liquid phase contains a large amount of acetone and a small amount of water when the crystallization operation is completed, the total volume of the liquid phase is larger than the initial liquid volume in the crystallization kettle, the crystallization of impurities in the wet-process phosphoric acid can be effectively prevented, and the improvement of the product purity is facilitated.
Drawings
FIG. 1 is a schematic flow chart of the present invention.
Detailed Description
The invention is further described with reference to specific embodiments, without limiting its scope.
Example 1
A method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization is specifically completed according to the following steps:
step one, adding wet-process phosphoric acid, urea and acetone into a crystallization kettle under the conditions of normal pressure, 60 ℃ and 100 r/min of rotating speed, and stirring at constant temperature for 1 h to prepare urea phosphate crystallization mother liquor, wherein the adding quality of urea is P contained in the wet-process phosphoric acid in the crystallization kettle2O50.9 times of the mass, the volume of acetone added is equal to the H contained in wet-process phosphoric acid in the crystallization kettle20.5-1.5 times of the volume of O;
and step two, evaporating the urea phosphate crystallization mother liquor prepared in the step one at the temperature of 60-70 ℃ and the rotating speed of 50-300 r/min, continuously feeding acetone into the urea phosphate crystallization mother liquor, controlling the evaporation rate of the liquid in the crystallization kettle to be 1.5 mL/min, the volume feeding rate of the acetone to be (1.5-3) mL/min, and when the volume ratio of the acetone to water in the liquid phase in the crystallization kettle is (5-8): 1, synchronously stopping evaporation and acetone feeding operation, then leading out crystal slurry in a crystallization kettle for solid-liquid separation, washing and drying a filter cake to obtain urea phosphate crystals;
the control of the extraction rate of the evaporation condensate in the crystallization kettle is 1.5 mL/min, which means that the volume of liquid extracted from the steam condensate in the crystallization kettle in unit time (min) is 1.5 mL, if the volume of the steam condensate generated in the crystallization kettle in unit time (min) is more than 1.5 mL, the extraction rate of the evaporation condensate is still 1.5 mL/min, and the residual condensate flows back into the crystallization kettle;
the acetone is fed into the urea phosphate crystallization mother liquor, namely the feeding port of the acetone is positioned below the liquid level of the urea phosphate crystallization mother liquor.
The crystallization kettle is a jacket stirring reaction kettle with controllable temperature.
The wet-process phosphoric acid is prepared by decomposing phosphate ore by adopting concentrated sulfuric acid, wherein P is2O5The content is 30-32 wt%.
Claims (3)
1. A method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization is characterized by comprising the following steps:
step one, adding wet-process phosphoric acid, urea and acetone into a crystallization kettle under the conditions of normal pressure, 60-70 ℃ and 50-300 r/min of rotating speed, and stirring at constant temperature for 0.5-1 h to prepare urea phosphate crystallization mother liquor, wherein the mass of added urea is P contained in wet-process phosphoric acid in the crystallization kettle2O50.85-0.9 times of the mass, and the adding volume of the acetone is equal to the H contained in the wet-process phosphoric acid in the crystallization kettle20.2-2.0 times of the volume of O;
and step two, evaporating the urea phosphate crystallization mother liquor prepared in the step one at the temperature of 60-70 ℃ and the rotating speed of 50-300 r/min, continuously feeding acetone into the urea phosphate crystallization mother liquor, controlling the extraction rate of evaporation condensate in a crystallization kettle to be V mL/min, the volume feeding rate of the acetone to be (1-5) V mL/min, and when the volume ratio of the acetone to water in the liquid phase in the crystallization kettle is (2.5-10): 1, synchronously stopping evaporation and acetone feeding operation, then leading out crystal slurry in a crystallization kettle for solid-liquid separation, washing and drying a filter cake to obtain urea phosphate crystals;
v is a real number which is more than or equal to 1 and less than or equal to 20;
the control of the extraction rate of the evaporation condensate in the crystallization kettle is V mL/min, which means that the volume of liquid extracted from the steam condensate in the crystallization kettle in unit time (min) is V mL, if the volume of the steam condensate generated in the crystallization kettle in unit time (min) is more than V mL, the extraction rate of the evaporation condensate is still V mL/min, and the rest condensate flows back into the crystallization kettle;
the acetone is fed into the urea phosphate crystallization mother liquor, namely the feeding port of the acetone is positioned below the liquid level of the urea phosphate crystallization mother liquor.
2. The method for producing urea phosphate by wet-process phosphoric acid decompression evaporation coupled elution crystallization as claimed in claim 1, wherein the crystallization kettle is a jacket stirring reaction kettle with controllable temperature.
3. The method for producing urea phosphate by wet-process phosphoric acid through reduced pressure evaporation coupled elution crystallization as claimed in claim 1, wherein the wet-process phosphoric acid is phosphoric acid prepared by decomposing phosphate ore with concentrated sulfuric acid, wherein P is P2O5The content is 20 to 50 wt%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911249572.2A CN110790685A (en) | 2019-12-09 | 2019-12-09 | Method for producing urea phosphate by wet-process phosphoric acid reduced pressure evaporation coupled elution crystallization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911249572.2A CN110790685A (en) | 2019-12-09 | 2019-12-09 | Method for producing urea phosphate by wet-process phosphoric acid reduced pressure evaporation coupled elution crystallization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110790685A true CN110790685A (en) | 2020-02-14 |
Family
ID=69447936
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911249572.2A Pending CN110790685A (en) | 2019-12-09 | 2019-12-09 | Method for producing urea phosphate by wet-process phosphoric acid reduced pressure evaporation coupled elution crystallization |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110790685A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114053978A (en) * | 2021-11-25 | 2022-02-18 | 上海师范大学 | Metal-containing waste purification device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005068106A (en) * | 2003-08-27 | 2005-03-17 | Daiso Co Ltd | Method for production and purification of 1,3-di(meth)allylurea |
| CN103709006A (en) * | 2013-12-18 | 2014-04-09 | 武汉科技大学 | Method for crystallizing erythritol fermentation liquid by evaporation-elution coupled process |
| CN104151203A (en) * | 2014-07-17 | 2014-11-19 | 瓮福（集团）有限责任公司 | Method for continuously producing urea phosphate by vacuum evaporation crystallization |
-
2019
- 2019-12-09 CN CN201911249572.2A patent/CN110790685A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005068106A (en) * | 2003-08-27 | 2005-03-17 | Daiso Co Ltd | Method for production and purification of 1,3-di(meth)allylurea |
| CN103709006A (en) * | 2013-12-18 | 2014-04-09 | 武汉科技大学 | Method for crystallizing erythritol fermentation liquid by evaporation-elution coupled process |
| CN104151203A (en) * | 2014-07-17 | 2014-11-19 | 瓮福（集团）有限责任公司 | Method for continuously producing urea phosphate by vacuum evaporation crystallization |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114053978A (en) * | 2021-11-25 | 2022-02-18 | 上海师范大学 | Metal-containing waste purification device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110054196B (en) | Method for preparing high-purity spherical instant boric acid by organic molecule induction | |
| CN104473120B (en) | A kind of production technology of monosodium glutamate | |
| CN110699756B (en) | Method for preparing alpha-type gypsum whisker by using ammonia-soda waste liquid | |
| CN104003362A (en) | Production method of dipotassium phosphate | |
| CN101156675A (en) | Glutamic acid abstraction technics combining rotation crystal | |
| CN113230688B (en) | Large-particle nickel sulfate continuous crystallization system and method | |
| CN104743581A (en) | Preparation technique of high-purity potassium chloride | |
| CN110745803A (en) | Method for preparing potassium dihydrogen phosphate from wet-process phosphoric acid | |
| CN103496715A (en) | Method for producing industrial grade superior ammonium sulfate through coked coarse ammonium sulfate dilution crystallization | |
| CN114988380A (en) | Method for producing food-grade monopotassium phosphate and co-producing high-purity gypsum by using feed-grade calcium hydrophosphate | |
| CN101863496A (en) | Method for preparing battery grade lithium carbonate by purifying industrial grade lithium carbonate | |
| CN115650256A (en) | Industrial potassium chloride purification process and production system | |
| CN110790685A (en) | Method for producing urea phosphate by wet-process phosphoric acid reduced pressure evaporation coupled elution crystallization | |
| CN103588223B (en) | Method for producing high-purity ammonium chloride through multistage flash evaporation, cooling and continuous crystallization | |
| CN102976990A (en) | Crystallization purification method of thiourea | |
| CN112678789A (en) | Method for preparing monopotassium phosphate by using monoammonium phosphate clear liquid | |
| CN110790684A (en) | Method for producing urea phosphate by using wet-process phosphoric acid as raw material through elution crystallization | |
| CN110790683A (en) | Method for producing urea phosphate by wet-process phosphoric acid elution coupling cooling crystallization | |
| CN115231990A (en) | Preparation method of high-purity dipentaerythritol | |
| CN112939032A (en) | Method for preparing potassium nitrate by nitric acid method | |
| CN104355990A (en) | Method for recycling and mechanically using L- (+) -tartaric acid in D-ethyl ester production | |
| CN203529949U (en) | Device for dilution crystallization of coked rough ammonium sulfate | |
| CN111004153A (en) | Method for producing urea phosphate by using wet-process phosphoric acid as raw material | |
| CN211078987U (en) | Device for producing urea phosphate by using wet-process phosphoric acid as raw material through elution crystallization | |
| CN208413873U (en) | A kind of device producing sodium bicarbonate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20200214 |