Recovery of residual lubricating oil from waste clay by flotation

The waste clay produced from refining waste lubricating oil contains about 30% oil. Laboratory research has been carried out on the selective separation of oil by flotation using linear barium alkyl benzene sulfonates as a collector. The behaviour of this collector at the solution-air interface is studied; the critical micelle concentration (CMC), efficiency (II), and effectiveness (P-C30) of the collector are determined. The effects of collector concentration and addition mode are investigated. The liquid-vapour interfacial tension was controlled by methanol. The selectivity achieved by the use of methanol is explained in terms of critical surface tension of floatability and CMC. In addition the physico-chemical characteristics of the recovered oil at optimum conditions are determined.