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Method for preparing high-purity calcium hydrogen phosphate

A calcium hydrogen phosphate, high-purity technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of environmental pollution of ammonia nitrogen wastewater and high cost of raw materials, and achieve low environmental pollution, low cost, and easy availability of raw materials Effect

Inactive Publication Date: 2014-07-23
SUQIAN MODERN BIOLOGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the existing production methods of calcium hydrogen phosphate are various, there are generally problems of high raw material costs or environmental pollution caused by the discharge of high ammonia nitrogen wastewater

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Embodiment 1-preparation for the first time

[0017] 1. Solution preparation

[0018] 1. Diammonium hydrogen phosphate solution: the concentration is 0.5mol / L, prepared by the reaction of ammonia gas and phosphoric acid solution, adjust the pH value to 7.8-8.0, and cool to a temperature of 15°C.

[0019] 2. Calcium chloride solution: the concentration is 0.5mol / L, the pH value is adjusted to 7-8, and the temperature is cooled to 15°C.

[0020] 2. Preparation and synthesis

[0021] 1. First add pure water to the first reaction tank, turn on the agitator, the stirring speed is 15r / min, and at the same time turn on the flowmeters of diammonium hydrogen phosphate solution and calcium chloride solution, the flow rates are 0.5m 3 / h, 0.5m 3 / h, the synthesis temperature is 15°C.

[0022] 2. Separating the mother liquor from the slurry, and washing the material cake (wet material of calcium hydrogen phosphate dihydrate) with pure water at the same time, so that the chlorid...

Embodiment 2

[0028] Embodiment 2-preparation for the first time

[0029] 1. Solution preparation

[0030] 1. Diammonium hydrogen phosphate solution: the concentration is 3.5mol / L, prepared by the reaction of ammonia gas and phosphoric acid solution, adjust the pH value to 7.8-8.0, and cool to a temperature of 45°C.

[0031] 2. Calcium chloride solution: the concentration is 3.5mol / L, the pH value is adjusted to 8-9, and the temperature is cooled to 45°C.

[0032] 2. Preparation and synthesis

[0033] 1. First add pure water to the first reaction tank, turn on the agitator, the stirring speed is 1500r / min, and at the same time turn on the flow meters of diammonium hydrogen phosphate solution and calcium chloride solution, the flow rates are 15m 3 / h, 15m 3 / h, the synthesis temperature is 45°C.

[0034] 2. Separating the mother liquor from the slurry, and washing the material cake (wet material of calcium hydrogen phosphate dihydrate) with pure water at the same time, so that the chlori...

Embodiment 3

[0040] Embodiment 3-recycling of mother liquor containing ammonium chloride

[0041] 1. Solution preparation:

[0042] 1. Diammonium hydrogen phosphate solution: concentration 2mol / L.

[0043] Recycling of mother liquor containing ammonium chloride: In the mother liquor containing ammonium chloride obtained in Example 1, add common industrial grade solid calcium oxide (calcium oxide content is 92%), pour into the In the reactor, under the condition of reaction temperature of 60°C and vacuum, the reaction time is 0.1h, so that ammonium chloride is decomposed to release ammonia gas. Steam the ammonia gas containing water vapor, absorb it with 85% phosphoric acid solution, add water to adjust the concentration to 2mol / L, adjust the pH value to 7.8-8.0, and cool to a temperature of 25°C.

[0044] 2. Calcium chloride solution: Precisely filter the remaining mother liquor from the above "distilled ammonia" to obtain a calcium chloride solution with a concentration of 2mol / L, adjus...

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Abstract

The invention discloses a method for preparing high-purity calcium hydrogen phosphate. The method comprises the specific process: adopting a phosphoric acid solution, liquid ammonia and a calcium chloride solution as initial raw materials, under a certain temperature, flow quantity and stirring, synthesizing calcium hydrogen phosphate dihydrate from a diammonium hydrogen phosphate solution and the calcium chloride solution by adopting a double decomposition process and under double liquid phases, and thus obtaining a calcium hydrogen phosphate dihydrate wet material and an ammonium chloride-containing mother solution; carrying out solid-liquid separation of the slurry, then washing with purified water until the content of chloride ions in a calcium hydrogen phosphate dihydrate filter cake is less than 0.05%, drying the calcium hydrogen phosphate dihydrate filter cake by a dryer to obtain the high-purity calcium hydrogen phosphate; and adding solid calcium oxide into the obtained ammonium chloride-containing mother solution, and carrying out ammonia steaming and all recycling. The method has the advantages of simple synthetic process, easy obtained raw materials, and low cost; and the by-product of the obtained ammonium chloride-containing mother solution can be all recycled, and has little pollution to the environment.

Description

technical field [0001] The invention relates to a method for preparing calcium hydrogen phosphate, in particular to a method for preparing high-purity calcium hydrogen phosphate, and belongs to the technical field of calcium hydrogen phosphate preparation. Background technique [0002] Calcium hydrogen phosphate is widely used in the food industry, such as nutritional food supplements, dough improvers and anti-coagulants, daily chemicals such as toothpaste, especially foaming toothpaste, and pharmaceutical nutrition in the pharmaceutical industry Additives and excipients, special optical glass and other industrial fields. Although the existing production methods of calcium hydrogen phosphate are various, there are generally problems of high raw material costs or environmental pollution caused by the discharge of high ammonia nitrogen wastewater. Contents of the invention [0003] Aiming at the problems in the above-mentioned prior art, the present invention provides a met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/32
Inventor 朱容均朱晓冰
Owner SUQIAN MODERN BIOLOGY TECH CO LTD
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