A low-cost process for preparing potassium dihydrogen phosphate by purifying wet-process phosphoric acid

A technology of potassium dihydrogen phosphate and wet-process phosphoric acid, applied in chemical instruments and methods, inorganic chemistry, phosphorus compounds, etc., can solve the problems of calcium sulfate precipitation mixed with phosphate and potassium ions, and achieve high utilization rate and reduce raw material consumption. , the effect of easy availability of raw materials

Active Publication Date: 2019-05-07
陈锂 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The object of the present invention is to provide a kind of raw material that is sufficient, easy to get, simple in process, can significantly reduce raw material consumption, low Process for preparing potassium dihydrogen phosphate from purified wet-process phosphoric acid with low cost and convenience for industrialized production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Preparation of calcium phosphate salt: add purified wet-process phosphoric acid into the reactor, add calcium oxide according to the ratio of 200% of the stoichiometric ratio, react at 70° C. for 3 hours, and then transfer to the metering tank. Purification of P in wet-process phosphoric acid 2 o 5 The quality score is 30%.

[0030] (2) Desulfurization: Add potassium sulfate with a mass fraction of 10% into the reactor, and under stirring, add composite auxiliary agent according to the ratio of 0.1% of the mass of potassium sulfate solution. The composite auxiliary agent consists of: dodecylamine polyoxyethylene ether (2) The mass fraction is 1%, and the mass fraction of L35 is 99%. Then after the reaction solution is heated to 40°C, add the calcium phosphate salt of step (1) according to the stoichiometric 1:1 ratio, control the pH at the end point of the solution between 4.5 and 4.8, after the addition, keep warm at 50°C for 4 hours, filter Calcium sulfate is r...

Embodiment 3

[0040] Embodiment 3: with embodiment 2, difference is:

[0041] (1) Preparation of calcium phosphate salt: add purified wet-process phosphoric acid into the reactor, add calcium hydroxide according to the ratio of 200% of the stoichiometric ratio, react at 40° C. for 2 hours, and then transfer to the metering tank. Purification of P in wet-process phosphoric acid 2 o 5 The quality score is 41%.

[0042] (2) Desulfurization: Add potassium sulfate with a mass fraction of 10% in the reactor, under stirring, add composite auxiliary agent according to the 1.3% ratio of potassium sulfate solution quality, composite auxiliary agent consists of: dodecylamine polyoxyethylene ether ( 15) The mass fraction is 99%, and the mass fraction of L35 is 1%. After the reaction solution was heated to 90°C, the calcium phosphate salt in step (1) was added, and after the addition was complete, the mixture was kept at 90°C for 4 hours.

[0043] K in calcium sulfate 2 O.P 2 o 5 content analysis...

Embodiment 4

[0045] Embodiment 4, with embodiment 2, difference is:

[0046] (1) Preparation of calcium phosphate salt: add purified wet-process phosphoric acid into the reactor, add calcium carbonate according to the stoichiometric ratio of 200%, react at 60° C. for 2 hours, and then transfer to the metering tank. Purification of P in wet-process phosphoric acid 2 o 5 The quality score is 35%.

[0047] (2) Desulfurization: adding potassium sulfate with a mass fraction of 20% into the reactor, under stirring, adding composite auxiliary agent according to 0.7% ratio of potassium sulfate solution mass, the composite auxiliary agent consists of: laurylamine polyoxyethylene ether ( 30) The mass fraction is 99%, and the mass fraction of L35 is 1%. After the reaction solution was heated to 50°C, the calcium phosphate salt in step (1) was added, and after the addition was complete, it was kept at 70°C for 4 hours.

[0048] K in calcium sulfate 2 O.P 2 o 5 content analysis, the result is: K...

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PUM

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Abstract

The invention discloses a low-cost technique for preparing potassium dihydrogen phosphate from purification wet-process phosphoric acid, which comprises the following steps: (1) preparation of calcium phosphate: reacting refined phosphoric acid with the P2O5 mass percent of 30-48% and calcium salt with the stoichiometry of 200%; and (2) desulfurization: adding a composite assistant composed of polyoxyethylene alkyl amine and propanediol block polyether into a 10-30 wt% potassium hydrogen sulfate or potassium sulfate solution (the composite assistant accounts for 0.1-1.3 wt% of the solution), adding the calcium phosphate in the step (1) at 40-90 DEG C according to the stoichiometric ratio of 1:1 until the pH value is 4.5-4.8, keeping the temperature at 50-90 DEG C for 4 hours, filtering to remove calcium sulfate, and carrying out concentration, crystallization, washing and drying on the mother solution to obtain the potassium dihydrogen phosphate. By adding the composite assistant into the reaction between the potassium hydrogen sulfate or potassium sulfate and calcium salt, the generated calcium sulfate crystal is regular and easy to filter; and the composite assistant can be adsorbed to the calcium sulfate crystal surface to lower the free energy of the calcium sulfate crystal surface, so that the phosphorus and potassium loss rate is low.

Description

technical field [0001] The invention belongs to the technical field of phosphate preparation, in particular to a method for preparing potassium dihydrogen phosphate from potassium sulfate or potassium bisulfate and wet-process phosphoric acid. Background technique [0002] Potassium dihydrogen phosphate is widely used in chemical industry, medicine, food, agriculture and animal husbandry and other industries, especially in agriculture, because potassium dihydrogen phosphate has high nutritional content and less application amount, it is suitable for various soils and crops, and can be used for soaking seeds , root soaking, foliage spraying and watering, so it has been developed rapidly and widely used in recent years. [0003] It is not difficult to prepare potassium dihydrogen phosphate technically. The key is the production cost. Focusing on cost reduction, the currently developed production processes mainly include: neutralization method, double decomposition method, extr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/30
Inventor 陈锂陈庚
Owner 陈锂
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