Recycle of calcium phosphate

A technology of phosphorous acid and sodium hypophosphite, applied in phosphorous acid, phosphorus oxyacid and other directions, can solve the problems of high energy consumption, complex operation process, high process condition requirements, etc., and achieve low energy consumption, simple process and product purity. high effect

Inactive Publication Date: 2013-08-28
HUBEI JIXING CHEM IND GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The above-mentioned technical operation process is complicated, the process conditions are high, and the energy consumption is also high.

Method used

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  • Recycle of calcium phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Take 400g of solid precipitate containing 48% calcium phosphite from the plate and frame filter press in the sodium hypophosphite production workshop, wash away the sodium hypophosphite in it with water, put it into a 2L flask with stirring, add 1000ml of water, heat and stir , add 180g of soda ash, raise the temperature of the feed liquid to 85°C, keep it warm and stir for 10h, and filter out the calcium carbonate precipitate while it is hot. Add 47g of the reclaimed phosphorous acid solution containing 50% phosphorous acid prepared in advance, adjust the pH to 5~6, remove excess soda ash, and pass through H 2 After S removes the heavy metal, obtain 1530g of 13.6% sodium phosphite solution, wherein H 2 S is generated by the reaction of sodium sulfide and phosphoric acid in the hydrogen sulfide reactor, and the excess H in the filtrate 2 S is recycled through the aeration tower.

[0013] On the cation exchange column equipped with D001 resin, the obtained sodium phosp...

Embodiment 2

[0015] Take 400g of solid precipitate containing 50% calcium phosphite from the plate and frame filter press in the sodium hypophosphite production workshop, wash off the sodium hypophosphite in it with water, put it into a 2L flask equipped with stirring, add 1000ml of water, heat and stir , add 185g of soda ash, raise the temperature of the feed solution to 90°C, keep stirring and react for 10h, and filter out the calcium carbonate precipitate while it is hot. Add 47g of the recovered phosphorous acid liquid containing 50% phosphorous acid prepared in advance, adjust the pH to 5~6, remove excess soda ash, and pass through H 2 After S removes the heavy metal, obtain 1535g of 14% sodium phosphite solution, wherein H 2 S is generated by the reaction of sodium sulfide and phosphoric acid in the hydrogen sulfide reactor, and the excess H in the filtrate 2 S is recycled through the aeration tower.

[0016] On the cation exchange column equipped with D001 resin, the obtained sodi...

Embodiment 3

[0018] Take 400g of solid precipitate containing 52% calcium phosphite from the plate and frame filter press in the sodium hypophosphite production workshop, wash away the sodium hypophosphite in it with water, put it into a 2L flask equipped with stirring, add 1000ml of water, heat and stir , add 180g of soda ash, raise the temperature of the feed solution to 85°C, keep it warm and stir to react for 5h, and filter out the calcium carbonate precipitate while it is hot. Add 47g of the recovered phosphorous acid liquid containing 50% phosphorous acid prepared in advance, adjust the pH to 5~6, remove excess soda ash, and pass through H 2 After S removes the heavy metal, obtain 1550g of 13.8% sodium phosphite solution, wherein H 2 S is generated by the reaction of sodium sulfide and phosphoric acid in the hydrogen sulfide reactor, and the excess H in the filtrate 2 S is recycled through the aeration tower.

[0019] On the cation exchange column equipped with D001 resin, the obta...

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Abstract

The invention relates to a process of extracting phosphorous acid from sodium hypophosphite slag, wherein a high purity phosphorous acid product is obtained specifically by a cation exchange method through decompression, distilling and crystallization. The process comprises the following steps: extracting calcium phosphate solid from a calcium phosphate in a calcium phosphate workshop and reacting with sodium carbonate; separating and purifying to obtain a sodium phosphite liquor; decompressing, evaporating and crystallizing the sodium phosphite liquor after cation exchange through D001 resin to obtain the high purity phosphorous acid product. The process is simple in process, less in energy consumption and high in product purity, and does not cause secondary pollution at the same time.

Description

technical field [0001] The invention relates to a process for extracting phosphorous acid from waste residue of sodium hypophosphite. Specifically, a cation exchange method is adopted to obtain high-purity phosphorous acid finished product through vacuum distillation and crystallization. Background technique [0002] The demand for sodium hypophosphite increases with the continuous expansion of the application range and production scale of electroless nickel plating. my country is a big producer of sodium hypophosphite. At present, domestic and foreign industrialized production methods generally adopt a one-step process. This process produces a large amount of calcium phosphite lime precipitation while obtaining sodium hypophosphite. This by-product is usually used as waste residue for filling Pit, polluting the environment. [0003] The method for treating waste slag in the production process of sodium hypophosphite disclosed in the patent document CN101172593: put the wast...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/163
Inventor 张志祥吴杰
Owner HUBEI JIXING CHEM IND GRP
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