Removal of organic contaminants from bauxite and other ores

摘要

A process for removing organic contaminants from a mineral ore such as bauxite. The ore is washed with an aqueous solution containing caustic soda, sodium carbonate or mixtures thereof in an amount up to about 80 g/l total alkali content (expressed as sodium carbonate equivalent). The ore is preferably washed at a temperature of about 95 DEG C. for about 5 hours with a solution containing about 20 g/l total alkali content. In a preferred embodiment, the ore is separated from a rinse solution containing degradation products of organic contaminants, and the washed ore is then dissolved in a caustic solution to produce Bayer process liquor. This process provides a means to reduce the organic carbon concentration in Bayer process liquor, with resultant increase in productivity of the Bayer process.