Method for producing light calcium carbonate and coproducing hydrogen sulfide by using crude calcium sulfide

Abstract

The invention relates to a method for producing light calcium carbonate and coproducing hydrogen sulfide by using crude calcium sulfide, belonging to the technical field of chemical production. The method comprises the steps of: pulverizing the crude calcium sulfide, and dissolving out the pulverized crude calcium sulfide by using saturated hydrogen sulfide solution at room temperature to obtain sulfur calcium hydroxide solution; removing other impurities in the crude calcium sulfide by filtering and washing, and introducing CO2 into clear solution to generate precipitation of light calcium carbonate and continuously generate hydrogen sulfide gas; preparing the saturated hydrogen sulfide solution by using part of the generated hydrogen sulfide gas, and delivering the rest of the hydrogen sulfide gas to a gas holder for storage; filtering and washing feed liquid generated from carbonatation reaction to obtain light calcium carbonate solid; introducing the hydrogen sulfide gas into the filtrate to prepare the saturated hydrogen sulfide solution, and returning to the previous step to dissolving out the crude calcium sulfide for recycling; and drying, crashing and packaging the light calcium carbonate to obtain a finished product of light calcium carbonate. The light calcium carbonate product has less impurity and high whiteness compared with that produced by the traditional method, and the byproduct hydrogen sulfide can be used as raw material of other chemical products.

Description

Technical field: [0001] The invention relates to a method for producing light calcium carbonate and co-producing hydrogen sulfide with coarse calcium sulfide, belonging to the technical fields of environmental protection and chemical production. Background technique: [0002] Light calcium carbonate (common name: precipitated calcium carbonate) is an important inorganic chemical product, widely used in plastics, rubber, paper, coatings and other industries. There are many ways to produce light calcium carbonate, but the domestic industrial production is mainly the carbonization method. The carbonization process is: calcining limestone and other raw materials to generate lime (the main component is calcium oxide) and carbon dioxide, adding water to digest the lime to produce milk of lime (the main component is calcium hydroxide), and then passing carbon dioxide to carbonize the milk of lime to form calcium carbonate precipitation , and finally the calcium carbonate precipita...

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Problems solved by technology

[0006] The purpose of the present invention is to effectively develop the downstream products of coarse calcium sulfide after the coarse calcium sulfide is obtained by high-temperature reduction, thereby solving the problem of environmental pollution by industrial by-product gypsum. The present invention refines and transforms the coarse calcium sulfide obtained by high-temperature reduction of industrial gypsum It is calcium hydrosulfide, and light calcium carbonate and hydrogen sulfide are prepared by the reaction of calcium hydrosulfide and carbon dioxide, which overcomes the shortcomings of the by-product industrial gypsum in the process of preparing hydrogen sulfide in Document 1, and the light calcium carbonate produced at the same time has lower impurity content than traditional production methods ,stable quality

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