Method for producing potassium dihydrogen phosphate with feed grade calcium hydrogen phosphate

A technology of potassium dihydrogen phosphate and calcium hydrogen phosphate, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of high production cost of potassium dihydrogen phosphate, easy corrosion of equipment, etc., and is convenient for large-scale industrial application. , Avoid strong corrosion, reduce product cost

Active Publication Date: 2016-02-17
上海新增鼎数据科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The present invention overcomes the deficiencies of the prior art and provides a method for producing potassium dihydrogen phosphate with feed grade calcium hydrogen phosphate and its implementation to solve the problems of high production cost and easy corrosion of equipment in the prior art

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Slowly add 1000kg of feed grade calcium hydrogen phosphate into the extraction reaction tank equipped with 2500kg of return lotion and industrial phosphoric acid solution at 70°C for conversion reaction. The reaction solid-liquid ratio is controlled at 1:2.5, and the reaction time is 1.5h.

[0027] After the conversion reaction is completed, add 585kg of industrial sulfuric acid to the reaction solution for extraction reaction. The molar ratio of sulfuric acid to calcium hydrogen phosphate is 1:0.9~1.1, which is in line with the conditions of the extraction reaction here. The solid-liquid ratio is controlled at 1:3, and the reaction temperature at 100°C, and the reaction time is 3 hours; after the reaction is completed, filter the reaction slurry, and the filtrate is crude phosphoric acid, and the P in crude phosphoric acid 2 o 5 The content of dihydrate gypsum is 40%, and the filter residue is dihydrate gypsum, which is discharged after repeated washing. It can be used...

Embodiment 2

[0031] Slowly add 1000kg of feed grade calcium hydrogen phosphate into the extraction reaction tank equipped with 3000kg of return lotion and industrial phosphoric acid solution at 90°C for conversion reaction. The reaction solid-liquid ratio is controlled at 1:3, and the reaction time is 1h.

[0032] After the conversion reaction is completed, add 585kg of industrial sulfuric acid to the reaction liquid, and carry out the extraction reaction according to the molar ratio of sulfuric acid to calcium hydrogen phosphate of 1:0.9~1.1, the solid-liquid ratio is controlled at 1:4, and the reaction temperature is 120°C. The reaction time is 4h; after the reaction is completed, the reaction slurry is filtered, and the filtrate is crude phosphoric acid, and the P in the crude phosphoric acid 2 o 5 The content is 30%, and the filter residue is dihydrate gypsum, which is discharged after repeated washing. It can be used in construction and cement industry, and is also a raw material for ...

Embodiment 3

[0036] Slowly add 1000kg of feed grade calcium hydrogen phosphate into the extraction reaction tank equipped with 2000kg of return lotion and industrial phosphoric acid solution at 60°C for conversion reaction. The reaction solid-liquid ratio is controlled at 1:2, and the reaction time is 1.5h.

[0037] After the conversion reaction is completed, add 585kg of industrial sulfuric acid to the reaction liquid, and carry out the extraction reaction according to the molar ratio of sulfuric acid and calcium hydrogen phosphate of 1:0.9~1.1, the solid-liquid ratio is controlled at 1:3, and the reaction temperature is 120°C. The reaction time is 2 hours; after the reaction is completed, the reaction slurry is filtered, and the filtrate is crude phosphoric acid, and the P in crude phosphoric acid 2 o 5 The content is 36%, and the filter residue is dihydrate gypsum, which is discharged after repeated washing. It can be used in construction and cement industry, and is also a raw material ...

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Abstract

The invention discloses a method for preparing monopotassium phosphate through feed-grade calcium hydrophosphate. The method comprises steps of carrying out conversion reaction on the raw material feed-grade calcium hydrophosphate and phosphoric acid solution, then carrying out extraction reaction with sulfuric acid, filtering so as to obtain filtrate, regulating pH of the filtrate to be 7.1-8.5 with industrial-grade phosphoric acid, then adding potassium carbonate and potassium hydroxide solution into the filtrate for neutralizing, after finishing the reaction, regulating pH to be 8.5-9.5, filtering so as to obtain filtrate, continuously regulating pH of the filtrate to be 4-4.5 through industrial-grade phosphoric acid, regulating the density of the reaction liquor, and after completely dissolving out the crystal, centrifugally drying so as to obtain monopotassium phosphate. The method is simple; the product can meet the requirement of first-grade goods of national industrial standard, the content of monopotassium phosphate is over 98%, and the yield of the product monopotassium phosphate is high, so that the method is applicable to large-scale industrial application; the method lowers the cost of the product by adopting low-cost feed-grade calcium hydrophosphate and returning the dehydration mother liquor back to a reaction kettle for cycle use, and avoids strong corrosion to equipment in the technological process.

Description

technical field [0001] Embodiments of the present invention relate to the preparation of phosphate in the chemical industry, more specifically, embodiments of the present invention relate to a method for producing potassium dihydrogen phosphate with feed grade calcium hydrogen phosphate. Background technique [0002] Potassium dihydrogen phosphate is a phosphate with high phosphorus and potassium content. It is widely used in industry, agriculture, health, food and other industries. The market demand is great, but the production cost of this product is relatively high. The production methods of potassium dihydrogen phosphate mainly include: neutralization method, extraction method, ion exchange method, double decomposition method, electrolysis method, direct method, crystallization method, etc. Our country mainly adopts the direct neutralization method, the process is simple, but expensive potassium hydroxide is needed, and the production cost is high, which limits the large...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/30
Inventor 钟林钟国林韩科
Owner 上海新增鼎数据科技有限公司
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