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Method for preparing high pure phosphoric acid from calcium hydrogen phosphate

A technology of calcium hydrogen phosphate and high-purity phosphoric acid, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of complex phosphoric acid process, high cost, and high energy consumption, and achieve simple process, low cost, and impurity content. low effect

Inactive Publication Date: 2015-01-28
贵州开磷磷酸盐化工有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for preparing high-purity phosphoric acid by calcium hydrogen phosphate, which solves the problems of complicated process, high cost, high energy consumption and many impurities in the preparation method of phosphoric acid in the prior art

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  • Method for preparing high pure phosphoric acid from calcium hydrogen phosphate

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Heat 600g of dilute sulfuric acid with a mass concentration of 60% to 70°C, slowly add 500g of feed-grade calcium hydrogen phosphate and 0.2g of phosphorus pentasulfide while stirring, keep stirring for 70min and filter, wash the filter cake once with 20ml of water, add triphosphate to the filtrate The mixture of butyl ester and cyclohexanone was 600ml, extracted twice, the extraction time was 5min, after the extraction, the organic phase was back-extracted with 100ml of water, the back-extraction time was 5min, and 400g of phosphoric acid was obtained, the mass content of phosphoric acid was 75.2%, and other indicators were all Reach the standard of high-purity phosphoric acid.

Embodiment 2

[0027] Heat 500g of dilute sulfuric acid with a mass concentration of 65% to 75°C, slowly add 455g of feed-grade calcium hydrogen phosphate and 0.18g of phosphorus pentasulfide, heat and stir for 90min to filter, wash the filter cake once with 25ml of water, and divide the filtrate into two parts with 600ml of tributyl phosphate. Secondary extraction, the extraction time is 20min, after the extraction, the organic phase is back-extracted with 90ml of water, the back-extraction time is 20min, 350g of phosphoric acid is obtained, the mass concentration of phosphoric acid is 74.5%, and other indicators meet the high-purity acid standard.

Embodiment 3

[0029] Heat 500g of dilute sulfuric acid with a mass concentration of 30% to 85°C, slowly add 455g of feed grade calcium hydrogen phosphate and 0.18g of phosphorus pentasulfide, keep stirring for 120min and filter, wash the filter cake once with 25ml of water, and divide the filtrate into two parts with 600ml of tributyl phosphate Secondary extraction, the extraction time is 15min, after the extraction, the organic phase is back-extracted with 90ml of water, the back-extraction time is 15min, 350g of phosphoric acid is obtained, the mass concentration of phosphoric acid is 74%, and other indicators meet the high-purity acid standard.

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Abstract

The invention discloses a method for preparing high pure phosphoric acid from calcium hydrogen phosphate. The high pure phosphoric acid is prepared by the steps of performing a replacement reaction on a calcium hydrogen phosphate precipitate produced by wet process phosphoric acid and a dilute sulphuric acid solution to obtain calcium sulfate and crude phosphoric acid; separating calcium sulfate and crude phosphoric acid to obtain the crude phosphoric acid; adding an extracting agent for reaction; separating an organic phase and a raffinate phase; recycling the raffinate phase for use; reverse-extracting the organic phase by using dilute sulphuric acid; and separating to obtain an organic phase cleaning solution. The method is simple in process, low in cost and short in production flow. The usage amount of the extracting agent is relatively small; impurity content is low; and extraction yield is high. The raw material of calcium hydrogen phosphate is easy to obtain; phenomenon of purification step by step in purification of the wet process phosphoric acid can be prevented; loss of phosphoric acid is reduced in the process; and by-product is phosphorus gypsum calcium sulphate with low content of impurities and can be further processed to prepare phosphorus gypsum crystal, so that difficult problem of accumulation process of the phosphorus gypsum can be solved; and the by-product having high economic value is obtained.

Description

technical field [0001] The invention relates to a method for preparing high-purity phosphoric acid from calcium hydrogen phosphate. Background technique [0002] At present, two methods are widely used in the production of high-purity phosphoric acid: one is thermal production. Although the phosphoric acid product has high purity, it can meet the requirements of industrial phosphoric acid; The price is higher. The other is to use sulfuric acid or hydrochloric acid to decompose phosphate rock and then process it to obtain crude phosphoric acid, and then extract the phosphoric acid therein with an extractant; although high-quality and high-purity phosphoric acid can be produced, the impurities in crude acid are There are many types, high content, and the selectivity of the extractant, resulting in a low extraction rate in the phosphoric acid extraction section, and complex stripping and purification processes after extraction. [0003] In the prior art, there are still many ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/222
Inventor 彭宝林廖吉星朱飞武张丽韩朝宋同彬潘礼富周勇王先炜郑超谢静
Owner 贵州开磷磷酸盐化工有限责任公司