CN-117623249-B - Method for separating chlorophosphine from mixed solution of chlorophosphine and ammonium chlorophosphate by utilizing anion membrane

Abstract

The invention discloses a method for separating phosphorus chloride in a mixed solution of phosphorus chloride and ammonium chloride by using an anion membrane, which comprises the following steps of adding hydrochloric acid into low-grade phosphorus ore pulp for decomposition to obtain a calcium-containing phosphorus chloride solution, adding a decalcification agent into the calcium-containing phosphorus chloride solution to remove calcium salt in the phosphorus chloride to obtain a mixed solution of the phosphorus chloride and the ammonium chloride, carrying out membrane separation on the mixed solution of the phosphorus chloride and the ammonium chloride by using an anion exchange membrane, obtaining ammonium phosphate or a phosphoric acid solution on the raw material side after separation, and obtaining hydrochloric acid with the mass concentration of 15-30% on the clean water side. The invention uses simple anion membrane to treat the mixed solution of the chlorophosphate and the ammonium chlorophosphate, and removes the chloride ions in the mixed solution, so that the high-value utilization of the phosphorus in the mixed solution of the chlorophosphate and the ammonium chlorophosphate is possible, and the high-value popularization of the process of decomposing low-grade phosphorite by hydrochloric acid is possible.

Inventors

• CAO XIAOFENG
• WANG PENGBAO
• HUANG ZHONG
• CHEN WEI
• HU FURONG
• CHEN CAOWEI
• LIU XUE

Assignees

• 西安思科赛实业有限公司

Dates

Publication Date

20260505

Application Date

20231108

Claims (6)

1. 1. The method for separating the chlorophosphoric acid from the mixed solution of the chlorophosphoric acid and the ammonium chlorophosphate by utilizing the anion membrane is characterized by comprising the following steps of: adding hydrochloric acid into low-grade phosphorus ore pulp, decomposing to obtain a calcium-containing chlorophosphate solution, adding a decalcifying agent into the calcium-containing chlorophosphate solution, and removing calcium salt in the chlorophosphate to obtain a chlorophosphate and ammonium chlorophosphate mixed solution; Separating the mixed solution of the chlorophosphate and the ammonium chlorophosphate by an anion exchange membrane to obtain an ammonium phosphate or phosphoric acid solution on the raw material side after separation, and obtaining hydrochloric acid with the mass concentration of 15-30% on the clear water side; when hydrochloric acid is added into low-grade phosphorite slurry, the mol ratio of CaO to hydrochloric acid in phosphorite is 1:1.9, the decomposition temperature is 40-75 ℃ and the time is 2-8h; the molar ratio of the decalcifying agent to the calcium ions in the chlorophosphate is 1.0-1.1:1; carrying out membrane separation on the mixed solution of the chlorophosphate and the ammonium chlorophosphate by an anion exchange membrane at the temperature of 35-90 ℃; The preparation method of the anion exchange membrane comprises dissolving anion membrane material in organic solvent, ultrasonic defoaming after dissolving thoroughly, and standing to obtain casting solution; the method comprises the steps of fully soaking a base film in an organic solvent, and then transferring the base film into a film casting solution for fully soaking, fixing the soaked base film on a polytetrafluoroethylene plate, then carrying out knife coating on the base film, and then drying in an oven to obtain an anion exchange film; The anion membrane material is a cyclic ammonium type phenolphthalein polyarylethersulfone membrane material, and is prepared through the following steps of adding cyclic ammonium type phenolphthalein, 4-difluorodiphenyl sulfone, biphenol, an alkaline compound, DMSO and toluene into a reaction flask under the protection of nitrogen, carrying out reflux reaction for 8 hours at 140 ℃, removing toluene and water through azeotropic distillation after the completion, then reacting for 12 hours at 180 ℃ to obtain a viscous polymerization solution, cooling to room temperature, adding DMSO to dilute, filtering solids, pouring into 70 ℃ water to obtain a polymer product, carrying out vacuum drying for 20-28 hours at 120 ℃ on the polymer product to obtain a PES-PPH-Pi polymer, dissolving the PES-PPH-Pi polymer in DMSO, adding methyl iodide with twice the amino molar weight in the PES-PPH-Pi polymer, stirring for 6-8 hours at room temperature, precipitating in ethanol to obtain the polymer, filtering, and carrying out vacuum drying for 24 hours at 80 ℃ to obtain the anion membrane material; The structural formula of the cyclic ammonium type phenolphthalein is shown as the formula (1): (1) In the formula (1), the R group is a nitrogen-containing heterocycle, and the nitrogen-containing heterocycle is piperidinyl, tetrahydropyrrolyl or morpholinyl.
2. 2. The method for separating chlorophosphoric acid from ammonium chlorophosphate mixed solution by utilizing an anionic membrane according to claim 1, wherein the grade of low-grade phosphorite is 16-24%.
3. 3. The method for separating chlorophosphoric acid from ammonium chlorophosphate mixed solution by utilizing an anionic membrane according to claim 1, wherein the decalcifying agent is ammonium sulfate or sulfuric acid.
4. 4. The method for separating chlorophosphoric acid from ammonium chlorophosphate mixed solution by utilizing an anionic membrane according to claim 1, wherein the mass concentration of hydrochloric acid is 20-33%.
5. 5. The method for separating chlorophosphate from ammonium chlorophosphate mixed liquor by utilizing an anionic membrane according to claim 1, which is characterized in that the removal of calcium salt in the chlorophosphate is carried out at the temperature of 40-75 ℃ for 2-8 hours.
6. 6. The method for separating the chlorophosphate from the mixed solution of the chlorophosphate and the ammonium chlorophosphate by utilizing the anion membrane according to claim 1 is characterized in that the molecular weight of the anion membrane material is 50000-150000, the base membrane is at least one of a PVDF membrane, a PTFE membrane, a PP membrane, a nylon net and a PP net, wherein the pore diameters of the PVDF membrane, the PTFE membrane and the PP membrane are 0.22-30 mu m, and the mesh numbers of the nylon net and the PP net are 100-400 meshes.

Description

Method for separating chlorophosphine from mixed solution of chlorophosphine and ammonium chlorophosphate by utilizing anion membrane Technical Field The invention belongs to the field of chemical production, and particularly relates to a method for separating chlorophosphoric acid from ammonium chlorophosphate mixed solution by utilizing an anionic membrane. Background A large amount of hydrochloric acid which is a byproduct in the sulfur-based fertilizer and chlor-alkali industry in China is difficult to use, and the use of hydrochloric acid to decompose phosphorite is an effective way for the normal use of low-grade phosphorite in the future. However, chlorine and phosphorus elements in the solution of the chlorophosphate or the solution of the ammonium chloride obtained after decalcification in the process of decomposing the phosphorite by the hydrochloric acid are difficult to separate, and the solution of the chlorophosphate or the solution of the ammonium chloride can only be used for producing the chlor-based fertilizer. The value of chlorine-based fertilizers is far lower than sulfur-based fertilizers or ammonium phosphate and cannot be used in many crops such as tobacco. At present, the separation method commonly used is to crystallize calcium chloride by cooling the chlorophosphate or volatilize hydrogen chloride by heating the system, and the two methods have the characteristics of high energy consumption, high corrosiveness, high equipment investment and high cost, and are not suitable for large-scale production devices at present. Therefore, how to remove chlorine element in the chlorophosphate or ammonium chloride solution becomes a difficult problem of the process for decomposing phosphorite by hydrochloric acid, and limits the large-scale use of the process. Disclosure of Invention Aiming at the problem of separating chlorine and phosphorus in a solution of the chlorophosphate or the ammonium chlorophosphate in the low-grade phosphorite by hydrochloric acid in the prior art, the invention aims to provide a method for separating the chlorophosphate in a mixed solution of the chlorophosphate and the ammonium chlorophosphate by utilizing an anion membrane. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The method for separating the chlorophosphine in the mixed solution of the chlorophosphine and the ammonium chlorophosphate by utilizing the anion membrane comprises the following steps: adding hydrochloric acid into low-grade phosphorus ore pulp, decomposing to obtain a calcium-containing chlorophosphate solution, adding a decalcifying agent into the calcium-containing chlorophosphate solution, and removing calcium salt in the chlorophosphate to obtain a chlorophosphate and ammonium chlorophosphate mixed solution; and (3) carrying out membrane separation on the mixed solution of the chlorophosphate and the ammonium chlorophosphate by an anion exchange membrane, obtaining an ammonium phosphate or phosphoric acid solution on the raw material side after the separation, and obtaining hydrochloric acid with the mass concentration of 15-30% on the clear water side. Further, when hydrochloric acid is added into the low-grade phosphorus ore pulp, the mol ratio of CaO to hydrochloric acid in the phosphorus ore is 1:1.9, the decomposition temperature is 40-75 ℃, and the time is 2-8h. Further, the grade of the low-grade phosphorite is 16-24%. Further, the decalcifying agent is ammonium sulfate or sulfuric acid. Further, the molar ratio of the decalcifying agent to the calcium ions in the chlorophosphate is 1.0-1.1:1. Further, the mass concentration of the hydrochloric acid is 20-33%. Further, the removal of the calcium salt from the chlorophosphate is carried out at a temperature of 40-75 ℃ for 2-8 hours. Further, membrane separation of the mixed solution of chlorophosphate and ammonium chlorophosphate by an anion exchange membrane is carried out at 35-90 ℃. The preparation method of the anion exchange membrane comprises the steps of dissolving an anion membrane material in an organic solvent, performing ultrasonic deaeration after the anion membrane material is fully dissolved, standing to obtain a membrane casting solution, fully soaking a base membrane in the organic solvent, transferring the base membrane into the membrane casting solution for full soaking, fixing the well-soaked base membrane on a polytetrafluoroethylene plate, then performing knife coating on the base membrane, and drying in an oven to obtain the anion exchange membrane. Furthermore, the molecular weight of the anion membrane material is 50000-150000, the base membrane is preferably at least one of PVDF membrane, PTFE membrane, PP membrane, nylon net and PP net, wherein the pore diameters of the PVDF membrane, the PTFE membrane and the PP membrane are 0.22-30 mu m, and the mesh numbers of the nylon net and the PP net are 100-400 meshes. Compared with the prior art, the invention h