Recovery of Pure Slaked Lime from Carbide Sludge: Case Study of Lagos State, Nigeria

Carbide sludge is the by-product of reaction between calcium carbide and water in the production of
acetylene gas for welding purposes. This by-product is discarded as waste due to high content of
impurities as a result of the reactants and reaction processes. In this research work an attempt was
made at developing an appropriate process technology for the recovery of pure slaked lime from
Nigeria’s automobile welders’ carbide sludge using solubilisation and evaporation process technology.
The percentage purity of the slaked lime recovered through the process was 88%. The recovered
slaked limes had pH of 11.93, were soluble in glycerol and dilute acid, insoluble in alcohol, and
sparingly soluble in water. The optimum percentage yield was 78.2% at a ratio of 1:1000(w/v) of
sludge to water held for 24 h at room temperature.