Abstract: A process for the reduction in fluoride concentration in a fluoride-contaminated sulphuric acid which process comprises treating said sulphuric acid with a silicon compound to produce silicon tetrafluoride, and removing said silicon tetrafluoride to produce a purer sulphuric acid having a substantially reduced fluoride concentration. The process is of particular use for the removal of fluoride from waste sulphuric acid in the copper smelting industry to meet environmental concerns.

Abstract: Disclosed is a process for rejuvenating and reclaiming useful hydrocarbon oils from contaminated waste oils. The process comprises dehydrating the waste oil and thereafter dissolving the dehydrated oil in a selected amount of isopropanol or N-propanol at a temperature of from 45.degree. C. to 80.degree. C. The undissolved waste matter is separated and the residual oil/solvent fraction is distilled to recover the decontaminated oil and the solvent. The recovered oil can be further clarified by treatment with a bleaching clay or activated carbon at elevated temperatures. The process is more efficient and economic than those known heretofore resulting in high yields of reclaimed oil and more environmentally acceptable waste products.