Calcium metal production process

Abstract

The invention relates to a calcium metal production process. The process comprises the following steps that S1, calcium carbide sludge slurry and hydrochloric acid waste liquid in a process for producing polyvinyl chloride through a chlor-alkali acetylene method serve as raw materials to be added into a contact agent to prepare calcium chloride mother liquor; S2, the calcium chloride mother liquoris subjected to drying and granulating to from anhydrous calcium chloride; S3, the anhydrous calcium chloride is added with potassium chloride and electrolytic copper and then is subjected to electrolyzing in an electrolytic cell to obtain a copper-calcium alloy and chlorine, wherein the chlorine is returned to the step S1 to react with the calcium carbide sludge slurry to generate calcium chloride mother liquor; and S4, the obtained copper-calcium alloy is added into a vacuum distillation furnace for distillation in a heat preservation state, and the calcium metal is purified under the protection of inert gas. According to the calcium metal production process, the waste calcium carbide sludge slurry in the chlor-alkali industry serves as a raw material to produce the calcium metal, the energy is saved, the consumption is reduced, and the purity of the calcium metal is high.

Description

technical field [0001] The invention relates to the technical field of chlor-alkali production, in particular to a production process for preparing metallic calcium by using waste calcium carbide mud slurry and hydrochloric acid waste liquid in the chlor-alkali industry. Background technique [0002] Calcium is a metal element with extremely active chemical properties. Metal calcium can be widely used in metallurgy, petrochemical and other industries as a reducing agent for purifying uranium in the nuclear industry, a reducing agent for the metallurgical industry, a deoxidizer for alloys, and a dehydrating agent for oil. At present, the production methods of metallic calcium mainly include the production process of preparing metallic calcium by electrolytic distillation of molten salt using calcium oxide as raw material and the production process of preparing metallic calcium by using calcium oxide as raw material aluminothermic reduction. The production of calcium metal by ...

AI Technical Summary

Problems solved by technology

The production of calcium metal by molten salt electrolytic distillation was introduced from the former Soviet Union in the 1950s and has been in operation for more than 50 years. During this period, no major upgrades have been carried out. The production process and equipment are still basically maintained at the level of the 1950s and 1960s, and the level of process automation is low. , the production efficiency is low, and because the production process has no supporting environmental protection facilities and monitoring means, the production site and exhaust emissions cannot meet the environmental protection requirements

[0003] On the other hand, in the process of producing polyvinyl chloride by chlor-alkali acetylene method, a large amount of calcium hydroxide as the main component of calcium carbide mud slurry is discharged as solid waste. It is used in the production of cement, mixed with fly ash to make bricks or stacked in the open air. The available added value is very low, and the filtrate must be treated before it can be reused. This not only reduces the recycling value of calcium carbide sludge, but also causes serious pollution to the environment.

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