Calcium metal production process

Abstract

The invention relates to a calcium metal production process, comprising: S1, calcium chloride mother liquor prepared by adding calcium chloride mother liquor after adding calcium carbide mud slurry and hydrochloric acid waste liquid in the process of producing polyvinyl chloride by chlor-alkali acetylene method as raw materials; The mother liquor is dried and granulated to become anhydrous calcium chloride; S3, adding the anhydrous calcium chloride to potassium chloride and electrolytic copper for electrolysis in an electrolytic cell to obtain copper-calcium alloy and chlorine gas, and the chlorine gas is returned to step S1 to be mixed with The calcium carbide mud slurry is reacted to generate calcium chloride mother liquor; S4, adding the obtained copper-calcium alloy to a vacuum distillation furnace for distillation under heat preservation, and purifying metallic calcium under the protection of an inert gas. The invention relates to a calcium metal production process using waste calcium carbide mud slurry in the chlor-alkali industry as a raw material to produce calcium metal, which saves energy and reduces consumption, and the calcium metal has higher purity.

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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