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Method for preparing potassium dihydrogen phosphate from calcium hydrogen phosphate

A technology of potassium dihydrogen phosphate and calcium hydrogen phosphate, applied in the direction of phosphate, phosphorus oxyacid, etc., can solve the problem that hydrogen chloride is difficult to use in large quantities

Inactive Publication Date: 2007-10-17
湖北中磷科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Judging from the results of current research, due to the harmful impurities in phosphate rock such as fluorine and silicon, KCl will be consumed due to the formation of potassium fluorosilicate into phosphogypsum. Iron and aluminum phosphate consume P in raw ore 2 o 5 , and the by-produced hydrogen chloride is difficult to utilize in large quantities, so that this method cannot be applied in industry

Method used

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  • Method for preparing potassium dihydrogen phosphate from calcium hydrogen phosphate
  • Method for preparing potassium dihydrogen phosphate from calcium hydrogen phosphate

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Raw material phosphate rock composition P 2 O 5 CaO MgO Ee 2 O 3 Al 2 O 3 SiO 2 F

[0035] Weight (%) 15.20 22.05 1.23 4.76 7.92 34.21 1.21

[0036] Weigh 1000 grams of phosphate rock powder (over 40 mesh) and decompose it with hydrochloric acid. prepare P 2 O 5 = 21% P -01 700 grams. Add 1000 ml of tap water to make pulp, neutralize with lime milk to pH=5-6, filter, wash, and dry at 70-80 °C to obtain P 2 O 5 = 40.86% calcium hydrogen phosphate 247 grams.

[0037] Take 70 grams of 98% industrial sulfuric acid, add 70 ml of tap water, heat to 100°C, and slowly put in 43 grams of agricultural potassium chloride with a purity of 95%. React at 100-140 ℃, remove HCl, add 200 ml of tap water to the reaction solution, heat to 100 ℃, slowly put in the slurry made of 100 grams of self-made calcium hydrogen phosphate and 150 ml of tap water, stir at 70-80 ℃, and react for 0.5 hours, suction filtration and washing, and the filtrate + washing water is concentra...

Embodiment 2

[0039] Raw material phosphate rock, same as Example 1

[0040] Take 70 grams of 98% industrial sulfuric acid, add 70 ml of tap water, heat to 100 ° C, slowly add 43 grams of agricultural potassium chloride with a purity of 95%, react at 100-140 ° C, remove HCl, and add 200 ml of tap water to the reaction solution. , heated to 100 ℃ and slowly injected into the slurry made of 100 grams of self-made calcium hydrogen phosphate and 150 ml of tap water, stirred and reacted at 75-80 ℃ for 0.5 hours, suction filtration, washing, filtrate + washing water concentrated volume 1 / 5, press its SO 4 2- Add lime milk desulfurization, suction filtration, filtrate + washing water, dropwise add saturated K 2 CO 3 The solution is neutralized to pH=6-7. After filtration, the iron-aluminum phosphate slag is returned to the main process to cool and separate out chlorides. The filtrate+washing water is adjusted to pH=4.3-4.7 with industrial phosphoric acid, and then concentrated by 1 / 3 volume. T...

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Abstract

The invention provides a method for preparing KH2PO4 with CaHPO4. The method contains the steps of: decomposing phosphorite with HCl to produce CaH2PO4Cl, which is further used to produce slurry with milk of lime for a neutralization reaction to prepare the deposit CaHPO4, or decomposing phosphorite with H2SO4 to prepare wet H3PO4 which is then neutralized with the milk of lime to produce the deposit CaHPO4, then the deposit CaHPO4 is reacted with H2SO4 and KCl to prepare KH2PO4. After washing and drying, white and clean ardealite is obtained, which can be used directly as construction materials and plasterboard etc. And the mother liquid is of closed circuit for zero discharge. The produced HCl is collected for decomposing phorphorite or prepare Cl-contained products. The chloride and the silica slag are baked together to prepare high active silica fertilizer and the F-contained waste gases are absorbed to produce fluorin products. Therefore, the invention realizes comprehensive fathering of the ''three-waste''.

Description

Technical field: [0001] The invention belongs to the wet process potassium phosphate technology. It is an intermediate product precipitated calcium hydrogen phosphate obtained by decomposing low-grade phosphate rock with hydrochloric acid, or preparing wet-process phosphoric acid by decomposing phosphate rock with sulfuric acid, neutralizing the obtained precipitated calcium hydrogen phosphate, and then reacting the precipitated calcium hydrogen phosphate with potassium chloride and sulfuric acid. And the technical scope of manufacturing potassium dihydrogen phosphate. Background technique: [0002] As we all know, potassium dihydrogen phosphate is a phosphate with high phosphorus and potassium content. However, the production cost is generally high, so how to adopt new processes and new technologies to reduce production costs is a matter of great concern in the industry. As far as the current production methods are concerned, there are thermal phosphoric acid and potash d...

Claims

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Application Information

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IPC IPC(8): C01B25/26
Inventor 姚鼎文孙勇姚宁郑兵
Owner 湖北中磷科技有限公司