Method for joint production of industrial-grade potassium dihydrogen phosphate and feed-grade calcium hydrogen phosphate by wet-process phosphoric acid

A technology of high-grade potassium dihydrogen phosphate and wet-process phosphoric acid, which is applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of difficult product purity, low purity of calcium hydrogen phosphate, and low economic value, and achieve good results. Social benefit and economic benefit, improvement of utilization value, effect of low quality requirement

Active Publication Date: 2020-12-22
SICHUAN UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

However, this method requires that the wet-process phosphoric acid used must be defluorinated in advance, which undoubtedly increases the cost; other impurities other than fluorine in the wet-process phosphoric acid affect the product potassium dihydrogen phosphate, making it difficult to reach the standard for product purity; in addition, calcium phosphate Contains a large amount of impurity precipitates, the purity of calcium hydrogen phosphate is low, it can only be used as low-end agricultural fertilizer, and its economic value is low

Method used

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  • Method for joint production of industrial-grade potassium dihydrogen phosphate and feed-grade calcium hydrogen phosphate by wet-process phosphoric acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] a.P 2 o 5 Concentration is 24.18wt% 1000g wet-process phosphoric acid, use tributyl phosphate TBP as extractant, carry out extraction reaction according to the volume ratio of wet-process phosphoric acid and extractant is 1:3, control reaction temperature to be 60 ℃, reaction time 30min, Stand still and separate phases to obtain organic phase I and aqueous phase I.

[0069] b. The organic phase I obtained in step a and 635.7 g of a potassium hydroxide solution with a mass fraction of 15 wt % are subjected to a stripping reaction, and the amount added is based on the potassium hydroxide in the stripping agent and the P in the organic phase I. 2 o 5 The molar ratio is calculated as 2:1, the reaction temperature is controlled at 60°C, the reaction time is 30min, and the phases are separated by standing to obtain the organic phase II and the aqueous phase II; wherein, the organic phase II is the regenerative extractant, and the aqueous phase II is the phosphoric acid diph...

Embodiment 2

[0078] a.P 2 o 5 Concentration is 1000g wet-process phosphoric acid of 35.72wt%, adopt n-butanol as extractant, carry out extraction reaction according to the volume ratio of wet-process phosphoric acid and extractant is 1:3, control reaction temperature to be 60 ℃, stand still and separate phases, obtain Organic phase I and aqueous phase I.

[0079] b. The organic phase I obtained in step a and 1760.9 g of potassium bicarbonate solution with a mass fraction of 20wt% are subjected to stripping reaction, and the amount added is based on the potassium bicarbonate in the stripping agent and the P in the organic phase I. 2 o 5 The molar ratio is calculated as 2:1, the reaction temperature is controlled at 60°C, the reaction time is 30min, and the phases are separated by standing to obtain the organic phase II and the aqueous phase II; wherein, the organic phase II is the regenerative extractant, and the aqueous phase II is the phosphoric acid diphosphate A crude solution of pot...

Embodiment 3

[0088] a.P 2 o 5 1000g of wet-process phosphoric acid with a concentration of 46.25wt%, using diisopropyl ether as the extractant, carrying out the extraction reaction at a volume ratio of wet-process phosphoric acid and extractant of 1:3, controlling the reaction temperature to 60°C, and standing for phase separation. An organic phase I and an aqueous phase I were obtained.

[0089] B, the organic phase I obtained in the step a and the potassium carbonate solution 1797.9g of mass fraction 15wt% carry out stripping reaction, add the potassium carbonate in stripping agent and the P in organic phase I 2 o 5 The molar ratio is calculated as 1:1, the reaction temperature is controlled at 60°C, the reaction time is 30min, and the phases are separated by standing to obtain the organic phase II and the aqueous phase II; wherein, the organic phase II is the regenerative extractant, and the aqueous phase II is the phosphoric acid diphosphate A crude solution of potassium hydrogen. ...

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Abstract

The invention relates to a method for co-production of industrial-grade potassium dihydrogen phosphate and feed-grade dicalcium phosphate from wet-process phosphoric acid and belongs to the technicalfield of chemical production. The technical problem to be solved by the invention is to provide the method for co-production of the industrial-grade potassium dihydrogen phosphate and the feed-grade dicalcium phosphate from wet-process phosphoric acid. The method includes a) subjecting the wet-process phosphoric acid to extraction with an extractant to obtain an organic phase I and a water phase I; b) subjecting the organic phase I and a stripping agent to back extraction to obtain an organic phase II and a water phase II; c) purifying the water phase II to obtain an industrial-grade potassiumdihydrogen phosphate product; d) neutralizing the water phase I with a first neutralization agent and performing solid-liquid separation to obtain filter cake I and a filtrate I; e) neutralizing thefiltrate I with a second neutralization agent, performing solid-liquid separation to obtain filter cake II and a filtrate II, and drying the filtrate II to obtain a feed-grade dicalcium phosphate product. The method has advantages of a simple process, a low cost, a high phosphorus utilization rate and good social and economic benefits.

Description

technical field [0001] The invention relates to a method for jointly producing industrial-grade potassium dihydrogen phosphate and feed-grade calcium hydrogen phosphate by wet-process phosphoric acid, and belongs to the technical field of chemical production. Background technique [0002] Potassium dihydrogen phosphate (MKP for short) is one of the important products in the phosphate industry, and its chemical formula is KH 2 PO 4 , It has a wide range of applications in agriculture, chemical industry, food and medicine and other industries. In agricultural fertilizers, potassium dihydrogen phosphate is a high-quality and efficient phosphorus-potassium compound fertilizer, and it is also an excellent fertilizer variety designated by the Ministry of Agriculture; potassium dihydrogen phosphate can also be used as a buffer and culture agent in the chemical industry; In the field of food, potassium dihydrogen phosphate can also be used as a food additive, such as chelating age...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/30C01B25/32C01B25/46
CPCC01B25/301C01B25/322C01B25/462C01B25/463C01B25/465C01P2006/80
Inventor 杨林庄海波张志业王辛龙邓强
Owner SICHUAN UNIV
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