Preparation method of granular anhydrous calcium hydrogen phosphate

Anhydrous calcium hydrogen phosphate, granular technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of small product particles, poor preparation stability, slow crystal growth, etc., to reduce the generation of powder. Effect

Active Publication Date: 2017-06-13
江苏德邦多菱健康科技有限公司
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

Its disadvantages are: poor preparation stability, slow crys...

Method used

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Embodiment 1

[0032]Embodiment 1, a preparation method of granular anhydrous calcium hydrogen phosphate: the method uses calcium carbonate or calcium hydroxide as a calcium source to react with phosphoric acid, and adds magnesium oxide as a seed accelerator to obtain calcium hydrogen phosphate; the reaction ends Finally, the product undergoes solid-liquid separation, drying, and the crystal water is removed to make anhydrous calcium hydrogen phosphate.

[0033] After the anhydrous calcium hydrogen phosphate is produced, the pH value of the product is adjusted by spraying a pH regulator, and then air-dried to produce neutral granular anhydrous calcium hydrogen phosphate. The pH regulator is acid-base calcium hydroxide.

Embodiment 2

[0034] Embodiment 2, a kind of preparation method of granular anhydrous calcium hydrogen phosphate, its concrete steps are as follows:

[0035] (1) Use calcium carbonate or calcium hydroxide as calcium source, adjust its concentration with purified water to obtain calcium carbonate or calcium hydroxide solution, the concentration of calcium carbonate or calcium hydroxide and purified water is 1:2; the mass of phosphoric acid solution Adjust the concentration to 20%, add 1‰ of its mass of magnesium oxide to the phosphoric acid solution; add calcium carbonate or calcium hydroxide solution dropwise to the phosphoric acid solution, react at room temperature, set the stirring speed at 200rpm, and neutralize to pH3 .2, the heating temperature rises to 40°C, neutralizes to a pH of 4.6, and the reaction is completed to obtain a slurry;

[0036] (2) Adjust the pH of the slurry to 6.5 with a calcium hydroxide solution with a mass concentration of 10%, filter until the water content of t...

Embodiment 3

[0038] Embodiment 3, a kind of preparation method of granular anhydrous calcium hydrogen phosphate, its concrete steps are as follows:

[0039] (1) Use calcium carbonate or calcium hydroxide as calcium source, adjust its concentration with purified water to obtain calcium carbonate or calcium hydroxide solution, the concentration of calcium carbonate or calcium hydroxide and purified water is 1:4; the mass of phosphoric acid solution Adjust the concentration to 25%, add magnesium oxide with a mass of 1.5‰ to the phosphoric acid solution; add calcium carbonate or calcium hydroxide solution dropwise to the phosphoric acid solution, react at room temperature, set the stirring speed at 300rpm, and neutralize to pH3 .8 o'clock, the heating temperature rises to 45 ° C, neutralizes to pH 4.8, and the reaction is completed to obtain slurry;

[0040] (2) Adjust the pH of the slurry to 7.0 with a calcium hydroxide solution with a mass concentration of 15%, filter until the water content...

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Abstract

The invention provides a preparation method of granular anhydrous calcium hydrogen phosphate. The method comprises the following steps: by taking calcium carbonate or calcium hydroxide as a calcium source, reacting with phosphoric acid; adding magnesium oxide as a crystal seed accelerant to prepare calcium hydrogen phosphate; after reacting, carrying out solid-liquid separation on a product; drying and removing crystalized water to prepare the anhydrous calcium hydrogen phosphate; after preparing the anhydrous calcium hydrogen phosphate, spraying a pH regulator and adjusting the pH value of the product; and drying through an air flow to prepare the neutral granular anhydrous calcium hydrogen phosphate. According to the preparation method, magnesium oxide is used as the crystal seed accelerant and a stabilizer, and primary drying is carried out, so as to keep the stability of product granules of calcium hydrogen phosphate and the stability of the pH value of a solution. Furthermore, the pH regulator is added and secondary drying is carried out, so as to further maintain the granule stability of the calcium hydrogen phosphate product; and powder is reduced and the neutral granular product is obtained.

Description

technical field [0001] The invention relates to a preparation method of calcium hydrogen phosphate, in particular to a preparation method of granular anhydrous calcium hydrogen phosphate. Background technique [0002] Calcium hydrogen phosphate, white monoclinic crystalline powder, odorless and tasteless. Usually dihydrate (its chemical formula is CaHPO 4 · 2H 2 O ) exists in the form of air and is stable in the air. When heated to 75°C, it begins to lose crystal water and become anhydrous, and at high temperature it becomes pyrophosphate. Soluble in dilute hydrochloric acid, dilute nitric acid, acetic acid, slightly soluble in water (100°C, 0.025%), insoluble in ethanol. In the prior art, the method for making calcium hydrogen phosphate mainly contains following several kinds: [0003] (1) Water extraction general calcium method. It is obtained from common agricultural calcium superphosphate through multi-stage water extraction, defluorination, and neutralization with...

Claims

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Application Information

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IPC IPC(8): C01B25/32
CPCC01B25/325C01B25/327
Inventor 赵祥海刘贞
Owner 江苏德邦多菱健康科技有限公司
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