Feasibility of producing gypsum from calcium carbide slag
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Is it feasible to use the calcium carbide slag generated as a by-product of PVC production for gypsum manufacturing? If so, what are the key issues to consider in the design of the production process?
It is recommended to use calcium carbide slag directly to produce cement clinker, as this yields much better economic benefits.
Is it used for desulfurization, or just for producing gypsum? The uses of gypsum are limited.
The main component of calcium carbide slag is calcium hydroxide, while gypsum is calcium sulfate; if calcium carbide slag is used to neutralize acidic wastewater, the resulting waste slag has gypsum as its main component. Not only is natural gypsum extremely abundant in our country, but there is also an overabundance of gypsum resulting from flue gas desulfurization in power plants and from the phosphorus industry. Unless gypsum is produced as a by-product necessary for neutralizing acidic water, it is highly impractical to deliberately use calcium carbide slag in a reaction with sulfuric acid to produce gypsum. The main method currently recommended in China for the comprehensive utilization of calcium carbide slag is cement production, with examples available in regions such as Anhui and Xinjiang.