Method for preparing calcium sulfate crystal whiskers by using natural gypsum

A technology of calcium sulfate whisker and natural gypsum, applied in chemical instruments and methods, calcium/strontium/barium sulfate, single crystal growth, etc., can solve the problem that raw materials cannot be fully utilized, environmental pollution, and poor quality of calcium sulfate whiskers and other problems, to achieve the effect of strengthening the promotion and application value, reducing production costs, and making the production process clean and environmentally friendly.

Inactive Publication Date: 2012-11-14
TAISHAN MEDICAL UNIV
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Problems solved by technology

[0007] The invention provides a method for preparing calcium sulfate whiskers by using natural gypsum, which aims to solve the problem that the method for preparing calcium sulfate whiskers provided by the prior art has highe...

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  • Method for preparing calcium sulfate crystal whiskers by using natural gypsum

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example 1

[0026]Example 1: Rinse 86g of natural gypsum to remove some impurities, then add it to the reactor, add 130ml of circulating solution or water, start stirring and heat to 45°C, add 40g of ammonium bicarbonate and 35ml of ammonia water in batches, and stir for 60min After vacuum filtration, ammonium sulfate solution and crude calcium carbonate were obtained. Take 64g of calcium carbonate crude product, add 300ml of 2.5mol / L hydrochloric acid solution, stir and react at 20-30°C for 20-30min, recover the CO produced by the reaction 2 After the reaction is completed, filter to remove impurities to obtain a calcium chloride solution; mix and react the obtained ammonium sulfate and calcium chloride solution at a molar ratio of 1:1 at room temperature according to their concentrations, and separate by filtration to obtain calcium sulfate precipitate and chloride Ammonium solution: take 5g of purified calcium sulfate, add 95g of water, stir evenly, adjust the pH to 9-10, place it in a...

example 2

[0027] Example 2: Rinse 1000g of natural gypsum to remove some impurities, then add it to the reaction kettle, add 2000ml of circulating solution or water, start stirring and heat to 55°C, add 610g of ammonium bicarbonate and 550ml of ammonia water in batches, and stir for 1 hour , the temperature was raised to 60° C. and the stirring reaction was continued for 1 h. After the reaction was completed, vacuum filtration was performed to obtain ammonium sulfate solution and crude calcium carbonate. Take 110g of crude calcium carbonate, add 540ml of 2.5mol / L hydrochloric acid solution, stir and react at 20-30°C for 20-30min, recover the CO produced by the reaction 2 Gas, after the reaction is completed, filter to remove impurities to obtain a calcium chloride solution. The obtained ammonium sulfate and calcium chloride solution are mixed and reacted at room temperature according to the molar ratio of 1:1 according to their concentrations, and separated by filtration to obtain calci...

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Abstract

The invention belongs to the technical field of chemical production and provides a method for preparing calcium sulfate crystal whiskers by using natural gypsum. The method comprises the steps of: firstly treating and purifying the natural gypsum by adopting a chemical method, enabling the natural gypsum to have double decomposition reaction with ammonium hydrogen carbonate and ammonia water to obtain ammonium sulfate and calcium carbonate, conducting solid-liquid separation to obtain ammonium sulfate solution and crude calcium carbonate, using hydrochloric acid to treat the byproduct crude calcium carbonate to obtain calcium chloride solution, removing impurities, and enabling the calcium chloride to react with the ammonium sulfate to obtain pure calcium sulfate; and then preparing the calcium sulfate crystal whiskers through a hydrothermal method by using the purified calcium sulfate. The method for preparing the calcium sulfate crystal whiskers by using the natural gypsum has the advantages that since the rich natural gypsum and low-cost chemical raw materials are used for producing high-added-value chemical products calcium sulfate crystal whiskers and byproducts ammonium chloride and carbon dioxide, the raw materials are fully utilized, the production cost is effectively reduced, the production process is clean and environmental-friendly, and the promotion and application values are very great.

Description

technical field [0001] The invention belongs to the technical field of chemical production, in particular to a method for preparing calcium sulfate whiskers from natural gypsum. Background technique [0002] Natural gypsum is one of the advantageous minerals in China. The proven reserves are 100 billion tons, ranking first in the world. At present, about 20 million tons of natural gypsum have been mined, 80% of which are used in the cement industry as cement retarders , used in agriculture, medicine, chemical industry, etc. only account for about 15%. Compared with the advanced countries in the world, the chemical utilization and deep processing technology of natural gypsum in China has a big gap. Therefore, making full use of China's resource advantages, developing deep processing technology for gypsum products, and producing high-performance and high-value-added chemical products is a problem that needs to be solved urgently. [0003] Whiskers refer to fibrous single cry...

Claims

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Application Information

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IPC IPC(8): C30B29/46C30B29/62C30B7/10C01F11/46
Inventor 杨荣华杨明晖
Owner TAISHAN MEDICAL UNIV
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