Lime Hydrate from Calcium Carbide

Very cheap acetylene lime was formerly produced as a byproduct of the manufacture of ethyne from calcium carbide  

Since most ethyne is now manufactured directly from crude oil or natural gas, this process is now only of minor importance. 

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Carbide lime is a waste lime hydrate by-product from the generation of acetylene from calcium carbide and may occur as a wet sludge or dry powder of widely varying purity and particle size. It is gray and has the pungent odor associated with acetylene (see Hydrocarbons, acetylene). 

Acetylene, one of the cheapest organic chemicals, is made from coal or from natural gas. The synthesis from coal involves heating lime and coke (roasted coal) in an electric furnace to produce calcium carbide. Addition of water to calcium carbide produces acetylene and hydrated lime. 

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