Electrolytic method for preparing potassium dihydrogen phosphate

A technology of potassium dihydrogen phosphate and dipotassium hydrogen phosphate, which is applied in the electrolysis process and electrolysis components, etc., can solve the problems of large damage to ion exchange membranes, increased equipment investment, and high impurity content, and achieves low environmental pollution, low cost, and high process efficiency. easy effect

Inactive Publication Date: 2012-10-17
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its disadvantage is that the price of ion exchange membrane is high, the requirements for impurity content in phosphoric acid and potassium salt are high, and the purification process of raw materials is relatively cumbersome.
However, if wet-process phosphoric acid is used as raw material, the impurity cont...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] The first step is the electrolytic reaction of dipotassium hydrogen phosphate and potassium chloride: the electrolytic device adopts a polyvinyl chloride electrolytic cell, with graphite as the anode, graphite as the cathode, and polyphenylene sulfide film as the electrolytic cell diaphragm material. Add 450g of dipotassium hydrogen phosphate solution with a concentration of 1mol / L into the cathode chamber of the electrolytic cell, and at the same time pump saturated or nearly saturated potassium chloride solution at 70°C into the anode chamber of the electrolytic cell, so that the anolyte is between the electrolytic cell and the liquid storage tank cycle. At a reaction temperature of 60°C, an electrolysis voltage of 2.1V, and a current density of 400A / m 2 Under the conditions of the electrolysis reaction for 0.5h, the hydrogen and chlorine generated by the electrolysis were dried and collected separately. A mixed solution of tripotassium phosphate and dipotassium hydr...

Embodiment 2

[0038]The first step is the electrolytic reaction of dipotassium hydrogen phosphate and potassium chloride: the electrolytic device adopts a steel electrolytic cell, and the metal oxide PbO 2 The electrode is the anode, Fe is the cathode, and the Asahi Nitrogen membrane is used as the diaphragm material of the electrolytic cell. Add 450g of dipotassium hydrogen phosphate solution with a concentration of 4mol / L into the cathode chamber of the electrolytic cell, and at the same time pump saturated or nearly saturated potassium chloride solution at 70°C into the anode chamber of the electrolytic cell, so that the anolyte is between the electrolytic cell and the liquid storage tank cycle. At a reaction temperature of 40°C, an electrolysis voltage of 3.0V, and a current density of 1000A / m 2 The electrolysis reaction was carried out for 12 hours under certain conditions, and the hydrogen and chlorine gas produced by electrolysis were dried and collected separately. A mixed solutio...

Embodiment 3

[0042] The first step is the electrolytic reaction of dipotassium hydrogen phosphate and potassium chloride: the electrolytic device adopts a plexiglass electrolytic cell, the metal oxide DSA electrode is used as the anode, Fe is used as the cathode, and ordinary asbestos membrane is used as the diaphragm material of the electrolytic cell. Add 450g of dipotassium hydrogen phosphate solution with a concentration of 8mol / L into the cathode chamber of the electrolytic cell, and at the same time pump saturated or nearly saturated potassium chloride solution at 70°C into the anode chamber of the electrolytic cell, so that the anolyte is between the electrolytic cell and the liquid storage tank cycle. At a reaction temperature of 100°C, an electrolysis voltage of 5V, and a current density of 3000A / m 2 The electrolysis reaction was carried out for 24 hours under certain conditions, and the hydrogen and chlorine gas produced by electrolysis were dried and collected separately. A mixe...

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PUM

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Abstract

The invention discloses an electrolytic method for preparing potassium dihydrogen phosphate, and is characterized in that a saturated or nearly saturated potassium chloride solution and a dipotassium hydrogen phosphate solution with a concentration of 1-8 mol/L, or a mixed solution of potassium dihydrogen phosphate and dipotassium hydrogen phosphate, or a mixed solution of dipotassium hydrogen phosphate and tripotassium phosphate, or a mixed solution of tripotassium phosphate and potassium hydroxide, are added into an electrolytic tank; under the conditions of a reaction temperature being 40-100 DEG C and an electrolyzing voltage being 2.1-5 V, continuous electrolysis is carried out to obtain a cathode complete solution; through concentration separation, a solid (or a heavy paste) is recycled into the electrolysis system; after a clear solution neutralizes a phosphoric acid, evaporation concentration, cooling crystallization, filtering, and drying are carried out to obtain a product potassium dihydrogen phosphate; a mother solution is neutralized by a catholyte after the electrolysis, and then returns to the electrolytic tank to undergo electrolysis; and at the same time, a chlorine gas and a hydrogen gas are by-products. The method of the invention overcomes the deficiencies of a high reaction temperature, high corrosion of equipment, high environmental pollution of the extraction method, a high material cost, and the like in the traditional complex decomposition method.

Description

technical field [0001] The invention relates to a method for preparing potassium dihydrogen phosphate by electrolysis, belonging to the field of preparation of potassium phosphate. technical background [0002] At present, there are many methods for producing potassium dihydrogen phosphate, including neutralization method, double decomposition method, conversion method, solvent extraction method, electrolysis method and so on. [0003] The simplest method is the neutralization method, such as neutralizing phosphoric acid with potassium hydroxide or potassium carbonate to obtain potassium dihydrogen phosphate. This method has the advantages of simple process flow and mature process technology, etc., but the disadvantages are large investment in raw materials and high production costs, and it is not suitable for large-scale production. [0004] Metathesis method, with potassium chloride and phosphoric acid, KCl and MH 2 PO 4 (Wherein M is Na or NH4) is the double decomposit...

Claims

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Application Information

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IPC IPC(8): C25B1/14C25B1/26
Inventor 杨林苟苹张志业王辛龙
Owner SICHUAN UNIV
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