CN115215310B - Impurity removal and recovery method for crude phosphoric acid - Google Patents
Impurity removal and recovery method for crude phosphoric acid Download PDFInfo
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- CN115215310B CN115215310B CN202210751015.6A CN202210751015A CN115215310B CN 115215310 B CN115215310 B CN 115215310B CN 202210751015 A CN202210751015 A CN 202210751015A CN 115215310 B CN115215310 B CN 115215310B
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- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 236
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 118
- 238000000034 method Methods 0.000 title claims abstract description 44
- 239000012535 impurity Substances 0.000 title claims abstract description 37
- 238000011084 recovery Methods 0.000 title description 3
- 229910001385 heavy metal Inorganic materials 0.000 claims abstract description 41
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 33
- 230000003009 desulfurizing effect Effects 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 18
- 239000007787 solid Substances 0.000 claims abstract description 17
- 239000003513 alkali Substances 0.000 claims abstract description 15
- 239000007788 liquid Substances 0.000 claims abstract description 15
- 239000007791 liquid phase Substances 0.000 claims abstract description 12
- 239000002002 slurry Substances 0.000 claims abstract description 12
- 238000004064 recycling Methods 0.000 claims abstract description 9
- 238000000926 separation method Methods 0.000 claims abstract description 8
- 239000012670 alkaline solution Substances 0.000 claims abstract description 5
- MHJAJDCZWVHCPF-UHFFFAOYSA-L dimagnesium phosphate Chemical compound [Mg+2].OP([O-])([O-])=O MHJAJDCZWVHCPF-UHFFFAOYSA-L 0.000 claims description 37
- 229910000395 dimagnesium phosphate Inorganic materials 0.000 claims description 37
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical group [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 claims description 26
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 25
- 238000003756 stirring Methods 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 13
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 8
- 239000011736 potassium bicarbonate Substances 0.000 claims description 7
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 7
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 7
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 6
- DPLVEEXVKBWGHE-UHFFFAOYSA-N potassium sulfide Chemical compound [S-2].[K+].[K+] DPLVEEXVKBWGHE-UHFFFAOYSA-N 0.000 claims description 4
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 3
- 235000011181 potassium carbonates Nutrition 0.000 claims description 3
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 2
- 125000005587 carbonate group Chemical group 0.000 claims description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims description 2
- CYQAYERJWZKYML-UHFFFAOYSA-N phosphorus pentasulfide Chemical compound S1P(S2)(=S)SP3(=S)SP1(=S)SP2(=S)S3 CYQAYERJWZKYML-UHFFFAOYSA-N 0.000 claims description 2
- 235000011118 potassium hydroxide Nutrition 0.000 claims description 2
- 229910052979 sodium sulfide Inorganic materials 0.000 claims description 2
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 12
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 abstract description 10
- 239000011777 magnesium Substances 0.000 abstract description 10
- 229910052749 magnesium Inorganic materials 0.000 abstract description 10
- 230000008901 benefit Effects 0.000 abstract description 7
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000009776 industrial production Methods 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 239000000706 filtrate Substances 0.000 description 13
- 238000001914 filtration Methods 0.000 description 8
- 239000002244 precipitate Substances 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 238000006386 neutralization reaction Methods 0.000 description 6
- 230000003472 neutralizing effect Effects 0.000 description 6
- 230000035484 reaction time Effects 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- 238000005406 washing Methods 0.000 description 6
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 5
- 239000011575 calcium Substances 0.000 description 5
- 229910052791 calcium Inorganic materials 0.000 description 5
- 239000002367 phosphate rock Substances 0.000 description 5
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 5
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 4
- -1 phosphorus pentasulfide potassium hydroxide Chemical compound 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000003674 animal food additive Substances 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- QWDJLDTYWNBUKE-UHFFFAOYSA-L magnesium bicarbonate Chemical compound [Mg+2].OC([O-])=O.OC([O-])=O QWDJLDTYWNBUKE-UHFFFAOYSA-L 0.000 description 2
- 229910000022 magnesium bicarbonate Inorganic materials 0.000 description 2
- 235000014824 magnesium bicarbonate Nutrition 0.000 description 2
- 239000002370 magnesium bicarbonate Substances 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- KCZFLPPCFOHPNI-UHFFFAOYSA-N alumane;iron Chemical compound [AlH3].[Fe] KCZFLPPCFOHPNI-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- CUGMJFZCCDSABL-UHFFFAOYSA-N arsenic(3+);trisulfide Chemical compound [S-2].[S-2].[S-2].[As+3].[As+3] CUGMJFZCCDSABL-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- FUFJGUQYACFECW-UHFFFAOYSA-L calcium hydrogenphosphate Chemical compound [Ca+2].OP([O-])([O-])=O FUFJGUQYACFECW-UHFFFAOYSA-L 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 235000019700 dicalcium phosphate Nutrition 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 239000003623 enhancer Substances 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 235000010855 food raising agent Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 229940056932 lead sulfide Drugs 0.000 description 1
- 229910052981 lead sulfide Inorganic materials 0.000 description 1
- 244000144972 livestock Species 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 235000016709 nutrition Nutrition 0.000 description 1
- 230000035764 nutrition Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
- C01B25/237—Selective elimination of impurities
- C01B25/238—Cationic impurities, e.g. arsenic compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
- C01B25/237—Selective elimination of impurities
- C01B25/2372—Anionic impurities, e.g. silica or boron compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/234—Purification; Stabilisation; Concentration
- C01B25/237—Selective elimination of impurities
- C01B25/2372—Anionic impurities, e.g. silica or boron compounds
- C01B25/2377—Sulfate
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/32—Phosphates of magnesium, calcium, strontium, or barium
- C01B25/34—Magnesium phosphates
-
- 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)
- Inorganic Chemistry (AREA)
- Removal Of Specific Substances (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention discloses a method for removing and recycling crude phosphoric acid, which comprises the following steps: (1) Mixing and reacting the crude phosphoric acid with alkaline solution of desulfurizing agent slurry and heavy metal removing agent, separating solid from liquid, concentrating liquid phase to obtain concentrated phosphoric acid A; (2) Mixing concentrated phosphoric acid A with alkali or alkali liquor until the pH value is 2-4, and carrying out solid-liquid separation, wherein the liquid phase is concentrated phosphoric acid B; (3) Mixing concentrated phosphoric acid B with alkali or alkali liquor until the pH value is 3-7, and carrying out solid-liquid separation. The method realizes the recycling of the crude phosphoric acid, effectively reduces the impurity content in the crude phosphoric acid, and the magnesium hydrophosphate recovered from the crude phosphoric acid meets the quality requirement of food grade, thereby realizing the efficient utilization of the crude phosphoric acid resource; the method has the advantages of simple process, low energy consumption and low cost, has better economic benefit and environmental protection benefit, and is convenient for realizing industrial production.
Description
Technical Field
The invention relates to the technical field of resource recycling, in particular to a method for removing impurities and recycling crude phosphoric acid.
Background
The calcium hydrogen phosphate can be used as a strengthening agent (supplementing calcium), a leavening agent, a food feed additive, an analysis reagent, a plastic stabilizer, an auxiliary feed for food and livestock and a feed additive. With the increase of population and the progress of economy of various countries, the market demand of food grade calcium hydrophosphate at home and abroad is growing, and the demand of large countries with population in China is larger and even needs to be maintained by import, so that the research and development of advanced technology is advanced, and the search of more production channels has profound significance for the industrial production of calcium hydrophosphate.
At present, phosphorus in food-grade calcium hydrophosphate is mainly derived from phosphorite or degummed bone block, but the latter is limited in use because of easy introduction of epidemic diseases carried by animals. The technology for producing food grade calcium hydrophosphate at home and abroad mainly comprises a wet phosphoric acid method and a thermal phosphoric acid method. The process is mature in a hot phosphoric acid method, but because the process has strict requirements on the quality of phosphorite, the phosphorite must be refined phosphorite (the fluorine content is about 3%), the whole process is heated by a high-temperature electric furnace and subjected to a strict impurity removal process, the electric energy consumption in the electric furnace heating process is about 3 times of that of wet phosphoric acid, the electric energy consumption is about 13 times of that of the wet phosphoric acid, the cost is even 30% higher than that of the wet phosphoric acid, and the dust is more, so that the phosphorite is replaced by the wet phosphoric acid method. The wet phosphoric acid process prepares wet phosphoric acid directly with inorganic acid acidolysis phosphate ore, and the impurity in the acid is related to ore grade, production process, impurity content, etc. and the crude phosphoric acid obtained through the wet phosphoric acid process has many impurities and needs to be purified to obtain phosphoric acid meeting the national standard as intermediate product of phosphoric acid industry for further deep processing.
In recent years, a great deal of research is being conducted on the purification of the extracted phosphoric acid in China, and the main problems at present are that the price of the extractant is relatively high, the cost is increased, and the extractant is difficult to recover. Therefore, if a method for removing impurities and recovering magnesium hydrogen phosphate which can remove impurities in crude phosphoric acid and can produce byproducts can be found, the method has important significance for improving economic benefit and social benefit and reducing economic cost.
Disclosure of Invention
The invention mainly solves the technical problem of providing the impurity removal and recovery method for the crude phosphoric acid, which can effectively remove impurities in the crude phosphoric acid, obtain magnesium hydrophosphate products with higher added values and realize the efficient utilization of crude phosphoric acid resources.
In order to solve the technical problems, the invention adopts a technical scheme that:
a method for removing and recycling crude phosphoric acid comprises the following steps:
(1) Mixing and reacting the crude phosphoric acid with alkaline solution of desulfurizing agent slurry and heavy metal removing agent, separating solid from liquid, concentrating liquid phase to obtain concentrated phosphoric acid A;
(2) Mixing concentrated phosphoric acid A with alkali or alkali liquor until the pH value is 2-4, and carrying out solid-liquid separation, wherein the liquid phase is concentrated phosphoric acid B;
(3) Mixing concentrated phosphoric acid B with alkali or alkali liquor until the pH value is 3-7, and carrying out solid-liquid separation.
In one embodiment of the invention, in (1), the solids content of the desulfurizing agent slurry is 5% to 70%, preferably 10% to 60%.
In one embodiment of the present invention, in (1), the desulfurizing agent is carbonate, further barium carbonate.
In one specific embodiment of the present invention, in (1), the heavy metal removing agent is selected from one of potassium sulfide, sodium sulfide, phosphorus pentasulfide, and hydrogen sulfide.
In one specific embodiment of the invention, the alkaline solution of the heavy metal remover is potassium hydroxide solution with the mass fraction of 0.01% -1%.
In one embodiment of the invention, in (1), the molar ratio of the desulfurizing agent to SO3 is 1:1;
the molar amount of the heavy metal removing agent is 3-5 times of the molar amount of heavy metal contained in the crude phosphoric acid.
In one embodiment of the present invention, in (1), the conditions of the mixing reaction are: the reaction temperature is 40-60 ℃, the time is 0.5-3 h, and the steam pressure is 0.6-1.0 MPa;
the stirring speed during mixing is 0.1-2 m/s.
In one specific embodiment of the present invention, in (1), the mass fraction of the concentrated phosphoric acid a is 33% to 55%.
In one specific embodiment of the invention, the mass fraction of the alkali liquor in the step (2) is 5-35%;
the solute of the alkali or alkali liquor is selected from one or more of potassium hydroxide, potassium carbonate and potassium bicarbonate.
In one embodiment of the present invention, the mixture in (3) is mixed to a pH of 2.5 to 3.5.
The crude phosphoric acid in the invention is obtained by wet phosphoric acid process, contains 100-300 ppm of heavy metals, mainly arsenic and lead, and has high heavy metals which can adversely affect ecological environment. The invention adopts the desulfurizing agent and the heavy metal removing agent to simultaneously desulfurize and remove heavy metal, utilizes barium sulfate crystals formed by desulfurization to promote the precipitation of fine arsenic sulfide and lead sulfide formed by heavy metal removal to simultaneously precipitate along with the barium sulfate, and avoids the problems of excessively fine crystallization, slow sedimentation, filtration, penetration and the like.
The crude phosphoric acid obtained by the wet phosphoric acid process also contains 1-5% of magnesium, and is usually removed as impurities in the process of removing heterocyclic rings from the crude phosphoric acid, the magnesium in the crude phosphoric acid is converted into magnesium hydrogen phosphate, and the magnesium hydrogen phosphate with the purity of more than 96% can be obtained after separation, so that the quality requirement of food grade magnesium hydrogen phosphate can be further purified, and the high-value utilization of valuable elements is realized.
The filtrate obtained by filtration in the production process of the invention can be recycled.
The invention has the following beneficial effects:
(1) The purity of the magnesium hydrogen phosphate obtained by the method reaches more than 96 percent, the quality requirement of the magnesium hydrogen phosphate serving as a food nutrition enhancer of national food safety standard of GB1903.48-2020 can be met, and the recycling of crude phosphoric acid resources is realized.
(2) The method effectively reduces the content of heavy metal impurities in the crude phosphoric acid.
(3) The method has simple process and low energy consumption and cost, and the magnesium hydrophosphate recovered from the crude phosphoric acid meets the food-grade requirement, has considerable economic benefit and environmental protection benefit, and is convenient for realizing industrial production.
Detailed Description
The following description of the present invention will be made clearly and fully, and it is apparent that the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The reagents used in the examples were commercially available unless otherwise specified.
The crude phosphoric acid in the embodiment of the invention is obtained by a wet phosphoric acid process, contains 100-300 ppm of heavy metals, and mainly contains arsenic and lead.
Example 1
(1) The crude phosphoric acid is subjected to one-step method impurity removal and concentration to prepare concentrated phosphoric acid: mixing coarse phosphoric acid with 60% solid content barium carbonate slurry as desulfurizing agent and potassium hydroxide solution of potassium sulfide as heavy metal eliminating agent in 3.5 wt% as desulfurizing agent SO 3 The molar ratio of the heavy metal remover to the crude phosphoric acid is 1:1, the molar amount of the heavy metal remover is 3 times of the molar amount of the heavy metal contained in the crude phosphoric acid, the reaction temperature is 60 ℃, and the reaction time is 3 hours; stirring speed2m/s, solid-liquid separation, concentration of liquid phase to obtain 55% concentrated phosphoric acid A, and steam pressure during concentration is 1.0MPa.
(2) Neutralization and impurity removal (iron aluminum): potassium bicarbonate was gradually added to concentrated phosphoric acid a to a pH of 3.5, and the precipitate was separated by filtration, and the filtrate was concentrated phosphoric acid B.
(3) Neutralizing and separating magnesium hydrogen phosphate: and adding 5% potassium hydroxide solution into the concentrated phosphoric acid B until the pH value is 7.0, slowly stirring and crystallizing to obtain magnesium hydrogen phosphate, washing and drying to obtain a magnesium hydrogen phosphate product, and obtaining the filtrate as concentrated phosphoric acid C.
The heavy metal content in the crude phosphoric acid after impurity removal is less than 20ppm, the purity of the obtained magnesium hydrophosphate is 97.8 percent, and the requirements of national standard GB1903.48-2020 are met.
Example 2
(1) The crude phosphoric acid is subjected to one-step method impurity removal and concentration to prepare concentrated phosphoric acid: mixing coarse phosphoric acid with 10% solid content desulfurizing agent barium carbonate slurry and 5% heavy metal removing agent phosphorus pentasulfide potassium hydroxide solution to react, and controlling the adding amount of barium carbonate and SO 3 The molar ratio is 1:1, the molar amount of the heavy metal remover is 5 times of the molar amount of heavy metal contained in the crude phosphoric acid, the reaction temperature is 60 ℃, and the reaction time is 0.5h; stirring at 0.1m/s, separating solid from liquid, concentrating the liquid phase to obtain 33% concentrated phosphoric acid A, and concentrating under 0.6MPa.
(2) Neutralization and impurity removal: potassium carbonate is gradually added into the concentrated phosphoric acid A until the pH value is 2.5, the precipitate is separated by filtration, and the filtrate is the concentrated phosphoric acid B.
(3) Neutralizing and separating magnesium hydrogen phosphate: and adding a potassium carbonate solution with the concentration of 35% into the concentrated phosphoric acid B until the pH value is 4, slowly stirring and crystallizing to obtain magnesium hydrogen phosphate, washing and drying to obtain a magnesium hydrogen phosphate product, and obtaining the filtrate as the concentrated phosphoric acid C.
The heavy metal content in the crude phosphoric acid after impurity removal is less than 20ppm, the purity of the obtained magnesium hydrophosphate is 97.3 percent, and the requirements of national standard GB1903.48-2020 are met.
Example 3
(1) The crude phosphoric acid is subjected to one-step method impurity removal and concentration to prepare concentrated phosphoric acid: potassium hydroxide of coarse phosphoric acid and desulfurizing agent barium carbonate slurry with solid content of 40% and heavy metal removing agent potassium sulfide with mass fraction of 0.4%Mixing the solution for reaction, and controlling the addition of barium carbonate and SO 3 The molar ratio is 1:1, the molar amount of the heavy metal remover is 3 times of the molar amount of heavy metal contained in the crude phosphoric acid, the reaction temperature is 60 ℃, and the reaction time is 2 hours; stirring at a speed of 1m/s, separating solid from liquid, concentrating the liquid phase to obtain 40% concentrated phosphoric acid A, and concentrating under a steam pressure of 0.8MPa.
(2) Neutralization and impurity removal: potassium hydroxide is gradually added into the concentrated phosphoric acid A until the pH value is 3, the precipitate is separated by filtration, and the filtrate is the concentrated phosphoric acid B.
(3) Neutralizing and separating magnesium hydrogen phosphate: adding potassium bicarbonate solution with the concentration of 15% into the concentrated phosphoric acid B until the pH value is 5, slowly stirring and crystallizing to obtain magnesium hydrogen phosphate, washing and drying to obtain a magnesium hydrogen phosphate product, and obtaining the filtrate of the concentrated phosphoric acid C.
The heavy metal content in the crude phosphoric acid after impurity removal is less than 20ppm, the purity of the obtained magnesium hydrophosphate is 97.5 percent, and the requirements of national standard GB1903.48-2020 are met.
Example 4
(1) The crude phosphoric acid is subjected to one-step method impurity removal and concentration to prepare concentrated phosphoric acid: mixing coarse phosphoric acid with 30% solid content barium carbonate slurry as desulfurizing agent and 0.3% heavy metal eliminating agent phosphorus pentasulfide potassium hydroxide solution to react, and controlling the adding amount of barium carbonate and SO 3 The molar ratio is 1:1, the molar amount of the heavy metal remover is 5 times of the molar amount of heavy metal contained in the crude phosphoric acid, the reaction temperature is 60 ℃, and the reaction time is 1.5 hours; stirring at 0.8m/s, separating solid from liquid, concentrating the liquid phase to obtain 40% concentrated phosphoric acid A, and concentrating under 0.7MPa.
(2) Neutralization and impurity removal: potassium bicarbonate was gradually added to concentrated phosphoric acid a to a pH of 3, and the precipitate was separated by filtration, and the filtrate was concentrated phosphoric acid B.
(3) Neutralizing and separating magnesium hydrogen phosphate: and adding potassium hydroxide into the concentrated phosphoric acid B until the pH value is 7.0, slowly stirring and crystallizing to obtain magnesium hydrogen phosphate, washing and drying to obtain a magnesium hydrogen phosphate product, and obtaining the filtrate as concentrated phosphoric acid C.
The heavy metal content in the crude phosphoric acid after impurity removal is less than 20ppm, the purity of the obtained magnesium hydrophosphate is 97.2 percent, and the requirements of national standard GB1903.48-2020 are met.
The purity of magnesium hydrophosphate obtained in the embodiments 1-4 of the invention reaches more than 96%, the requirements of the national standard GB1903.48-2020 are met, and the impurity content in the crude phosphoric acid after impurity removal is less than 20ppm.
Comparative example 1
In comparison with example 1, only the pH value in step (2) was different, and the rest was the same.
(2) Neutralization and impurity removal: potassium bicarbonate was gradually added to concentrated phosphoric acid a to a pH of 1.5, and the precipitate was separated by filtration, and the filtrate was concentrated phosphoric acid B.
The purity of the obtained magnesium hydrogen phosphate is 85.2%.
Comparative example 2
In comparison with example 1, only the pH value in step (2) was different, and the rest was the same.
(2) Neutralization and impurity removal: potassium bicarbonate was gradually added to concentrated phosphoric acid a to a pH of 5, and the precipitate was separated by filtration, and the filtrate was concentrated phosphoric acid B. The pH value is 5, and the purity of the obtained magnesium hydrogen phosphate is 89.5 percent.
Comparative example 3
In comparison with example 1, only the pH value in step (3) was different, and the rest was the same.
(3) Neutralizing and separating magnesium hydrogen phosphate: and adding potassium hydroxide into the concentrated phosphoric acid B until the pH value is 2.0, slowly stirring and crystallizing to obtain magnesium hydrogen phosphate, washing and drying to obtain a magnesium hydrogen phosphate product, and obtaining the filtrate as concentrated phosphoric acid C.
The purity of the obtained magnesium hydrogen phosphate is as follows: 85.6%.
Comparative example 4
In comparison with example 1, only the pH value in step (3) was different, and the rest was the same.
(3) Neutralizing and separating magnesium hydrogen phosphate: and adding potassium hydroxide into the concentrated phosphoric acid B until the pH value is 8.0, slowly stirring and crystallizing to obtain magnesium hydrogen phosphate, washing and drying to obtain a magnesium hydrogen phosphate product, and obtaining the filtrate as concentrated phosphoric acid C.
The purity of the obtained magnesium hydrogen phosphate is as follows: 87.3%.
Comparative example 5
In comparison with example 1, only the reaction temperature in step (1) was different, and the rest was the same.
(1) The crude phosphoric acid is subjected to one-step method impurity removal and concentration to prepare concentrated phosphoric acid: will beMixing and reacting crude phosphoric acid with 30% of solid content of desulfurizing agent barium carbonate slurry and 0.3% of heavy metal removing agent phosphorus pentasulfide potassium hydroxide solution, and controlling the addition of barium carbonate and SO 3 The molar ratio is 1:1, the molar amount of the heavy metal remover is 5 times of the molar amount of heavy metal contained in the crude phosphoric acid, the reaction temperature is 30 ℃, and the reaction time is 1.5 hours; stirring at 0.8m/s, separating solid from liquid, concentrating the liquid phase to obtain 40% concentrated phosphoric acid A, and concentrating under 0.7MPa.
The purity of the obtained magnesium bicarbonate is as follows: 88.4%.
Comparative example 6
In comparison with example 1, only the reaction temperature in step (1) was different, and the rest was the same.
(1) The crude phosphoric acid is subjected to one-step method impurity removal and concentration to prepare concentrated phosphoric acid: mixing coarse phosphoric acid with 30% solid content barium carbonate slurry as desulfurizing agent and 0.3% heavy metal eliminating agent phosphorus pentasulfide potassium hydroxide solution to react, and controlling the adding amount of barium carbonate and SO 3 The molar ratio is 1:1, the molar amount of the heavy metal remover is 5 times of the molar amount of heavy metal contained in the crude phosphoric acid, the reaction temperature is 70 ℃, and the reaction time is 1.5 hours; stirring at 0.8m/s, separating solid from liquid, concentrating the liquid phase to obtain 40% concentrated phosphoric acid A, and concentrating under 0.7MPa.
The purity of the obtained magnesium bicarbonate is as follows: 91.9%.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.
Claims (9)
1. The method for removing impurities and recycling coarse phosphoric acid to obtain magnesium hydrogen phosphate is characterized by comprising the following steps:
(1) Mixing and reacting the crude phosphoric acid with alkaline solution of desulfurizing agent slurry and heavy metal removing agent, separating solid from liquid, concentrating liquid phase to obtain concentrated phosphoric acid A;
(2) Mixing concentrated phosphoric acid A with alkali liquor until the pH value is 2-4, carrying out solid-liquid separation, wherein the liquid phase is concentrated phosphoric acid B;
(3) Mixing concentrated phosphoric acid B with alkali liquor until the pH value is 3-7, and carrying out solid-liquid separation;
in the step (1), the molar amount of the heavy metal removing agent is 3-5 times of the molar amount of heavy metal contained in the crude phosphoric acid;
in the step (1), the condition of the mixing reaction is that the reaction temperature is 40-60 ℃, the time is 0.5-3 h, the steam pressure is 0.6-1.0 MPa, and the stirring speed during mixing is 0.1-2 m/s;
in the step (2), the mass fraction of the alkali liquor is 5% -35%, and the solute of the alkali liquor is one or more selected from potassium hydroxide, potassium carbonate and potassium bicarbonate.
2. The method for removing impurities and recovering magnesium hydrogen phosphate according to claim 1, wherein in the step (1), the solid content of the desulfurizing agent slurry is 5% -70%.
3. The method for removing impurities and recovering magnesium hydrogen phosphate according to claim 1, wherein in the step (1), the solid content of the desulfurizing agent slurry is 10% -60%.
4. The method for purifying magnesium hydrogen phosphate according to claim 2, wherein in the step (1), the desulfurizing agent is carbonate.
5. The method for purifying magnesium hydrogen phosphate according to claim 2, wherein in the step (1), the desulfurizing agent is barium carbonate.
6. The method for purifying magnesium hydrogen phosphate according to claim 1, wherein in the step (1), the heavy metal removing agent is one selected from potassium sulfide, sodium sulfide, phosphorus pentasulfide and hydrogen sulfide.
7. The method for removing impurities and recycling magnesium hydrogen phosphate according to claim 6, wherein the alkaline solution of the heavy metal remover is a potassium hydroxide solution with a mass fraction of 0.01% -1%.
8. The method for removing impurities and recycling magnesium hydrogen phosphate according to claim 1, wherein in the step (1), the mass fraction of the concentrated phosphoric acid A is 33% -55%.
9. The method for purifying and recovering magnesium hydrogen phosphate according to claim 1, wherein the pH is 2.5 to 3.5.
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| FR1466733A (en) * | 1966-01-29 | 1967-01-20 | Knapsack Ag | Process for the preparation of dibasic magnesium phosphate trihydrate |
| GB1069725A (en) * | 1965-01-29 | 1967-05-24 | Knapsack Ag | Process for the manufacture of magnesium hydrogen phosphate trihydrate |
| CN1994871A (en) * | 2006-12-13 | 2007-07-11 | 云南省化工研究院 | Method for preparing technical grade phosphate using wet method phosphoric acid as raw material |
| CN107021467A (en) * | 2017-03-29 | 2017-08-08 | 河南师范大学 | A kind of preparation method of magnesium monohydrogen phosphate hydroxyapatite core-shell material |
| CN108328592A (en) * | 2018-03-16 | 2018-07-27 | 成都理工大学 | A kind of technique for using phosphoric acid by wet process to produce magnesium monohydrogen phosphate for raw material |
| CN114314540A (en) * | 2021-12-29 | 2022-04-12 | 中国地质科学院矿产综合利用研究所 | Method for producing magnesium hydrogen phosphate by using phosphate tailings |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102014006278B3 (en) * | 2014-05-02 | 2015-02-26 | Remondis Aqua Gmbh & Co. Kg | A process for purifying crude phosphoric acid (e.g., MGA acid) by adding ashes from waste incinerators comprising recovery of pure phosphoric acid, calcium sulfate, water soluble calcium hydrogen phosphates, and metal salt solution |
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| GB1069725A (en) * | 1965-01-29 | 1967-05-24 | Knapsack Ag | Process for the manufacture of magnesium hydrogen phosphate trihydrate |
| FR1466733A (en) * | 1966-01-29 | 1967-01-20 | Knapsack Ag | Process for the preparation of dibasic magnesium phosphate trihydrate |
| CN1994871A (en) * | 2006-12-13 | 2007-07-11 | 云南省化工研究院 | Method for preparing technical grade phosphate using wet method phosphoric acid as raw material |
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| CN108328592A (en) * | 2018-03-16 | 2018-07-27 | 成都理工大学 | A kind of technique for using phosphoric acid by wet process to produce magnesium monohydrogen phosphate for raw material |
| CN114314540A (en) * | 2021-12-29 | 2022-04-12 | 中国地质科学院矿产综合利用研究所 | Method for producing magnesium hydrogen phosphate by using phosphate tailings |
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