Method for preparing monopotassium phosphate from fertilizer grade calcium hydrophosphate

A technology of potassium dihydrogen phosphate and calcium hydrogen phosphate, which is applied in the field of phosphate, can solve the problems of high price, high energy consumption, and high raw material requirements, and achieve the effects of low cost, low energy consumption, and high product quality

Inactive Publication Date: 2013-04-24
WENGFU (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the requirements for raw materials are high, the price is relatively expensive, and the energy consumption in the production process is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Take 194kg of potassium hydrogen sulfate and 600kg of water and mix them evenly in the reaction tank. Take 200kg of fertilizer grade calcium hydrogen phosphate and slowly add them to the reaction tank. °C, the reaction time is 6.5h. Suction filtration and washing, the filter residue is produced as phosphogypsum whiskers, adjust the pH of the filtrate to 4.5, remove impurities from the filtrate, concentrate, crystallize, centrifuge and dehydrate to form a mother liquor and return to step a. Obtain 180.31kg potassium dihydrogen phosphate, wherein P 2 o 5 =51.27%,K 2 O=33.58%, in line with the HG-2321-92 Agricultural Potassium Dihydrogen Phosphate Standard first-class product.

Embodiment 2

[0020] Take 215kg of potassium hydrogen sulfate and 1000kg of water and mix them evenly in the reaction tank. Take 200kg of fertilizer grade calcium hydrogen phosphate and slowly add them to the reaction tank. ℃, the reaction time is 8h. Suction filtration and washing, the filter residue is produced as phosphogypsum whiskers, the pH value of the filtrate is adjusted to 5.5, the filtrate is impurity-removed, concentrated, crystallized, centrifuged and dehydrated to produce mother liquor and returned to step a. Obtain 185.03kg potassium dihydrogen phosphate, wherein P 2 o 5 =51. 31%,K 2 O=34.09%, in line with the HG-2321-92 agricultural potassium dihydrogen phosphate standard first-class product.

Embodiment 3

[0022] Take 199kg of potassium hydrogen sulfate and 800kg of water and mix them evenly in the reaction tank. Take 200kg of fertilizer grade calcium hydrogen phosphate and slowly add them to the reaction tank. °C, the reaction time is 7.5h. Suction filtration and washing, the filter residue is produced as phosphogypsum whiskers, the pH value of the filtrate is adjusted to 5, the filtrate is removed from impurities, concentrated, crystallized, centrifuged and dehydrated to produce mother liquor and returned to step a. Obtain 183.72kg potassium dihydrogen phosphate, of which P 2 o 5 =51.25%, K 2 O=33.72%, in line with the HG-2321-92 Agricultural Potassium Dihydrogen Phosphate Standard first-class product.

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Abstract

The invention relates to a method for preparing monopotassium phosphate from fertilizer grade calcium hydrophosphate. The method comprises the following steps of: slowly adding the fertilizer grade calcium hydrophosphate used as a material into a reaction tank containing potassium hydrogen sulfate solution at 60-68 DEG C, controlling the reaction solid-to-liquid ratio at (1:3)-(1:5) and the reaction time at 6.5-8 hours; controlling the sulphur and phosphorus mass ratio of the potassium hydrogen sulfate to the calcium hydrophosphate in reaction to S to P being (1-1.2):(1-1.4); adjusting the pH value of the filtrate by use of 85% industrial phosphoric acid; generating byproduct calcium sulfate whisker by filtering after the reaction is finished, adjusting the pH value of the filtrate to 4.5-5.5, and preparing the monopotassium phosphate product of meeting the top-quality goods of the national industry standard from the filtrate by purifying, concentrating, crystallizing, dewatering and drying, and controlling the drying temperature at 80-100 DEG C. By adopting the method, the technological process of producing the monopotassium phosphate is simple in flow, low in production cost, free of the three wastes, and easy for realization of large-scale and industrial production.

Description

technical field [0001] The present invention relates to phosphate, in particular to a method for producing potassium dihydrogen phosphate. Background technique [0002] Potassium dihydrogen phosphate is a phosphate with high phosphorus and potassium content, which is widely used in agriculture, industry, health and other industries. However, the production cost is generally relatively high, so how to adopt new processes and new technologies to reduce costs is a matter of great concern in the industry. At present, there are many production methods of potassium dihydrogen phosphate, mainly neutralization method, extraction method, ion exchange method, double decomposition method, direct method, crystallization method and electrolysis method. In my country, the production process mostly adopts the neutralization method. Although the neutralization method is simple, potassium hydroxide is expensive and the production cost is high, which limits large-scale production; while the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/30
Inventor 胡宏解田杨俊薛绍秀杨丽萍
Owner WENGFU (GRP) CO LTD
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