Process for the destabilization and separation of ilmenite (FEO TIO2) tailings

摘要

The separation of humates and silica from sands containing ilmenite (FeO.TiO2) and other heavy metals during ground level dredge mining of FeO.TiO2 from ancient beach sand wherein the tailings as discard contain organic matter, largely humates, as colloidal dispersion, together with a major amount of silica present as a slurry which is forwarded to conduits and piles. This improved process comprises adding to the tailings 6-400 ppm of an organic cationic condensate and particularly a polymeric cationic organic amine. Preferred polymers or condensates are epichlorohydrin (epi)/ammonia and ethylene dichloride/-dimethyalamine (DMA) quaternized with methyl chloride. The concurrent use of high shear agitation in mixing the cationic condensate with the tailings dispersion as, for example, utilizing the mixture as input to the suction side of a centrifugal pump, allows the amount of cationic treating agent to be drastically reduced from a range of about 240-400 to 6-50 ppm. Further, the incorporation of the treating agents into a type of closed cycle or no-exit process where the tailings are piled up in a contiguous area of the mining operation has definite advantages over prior processes because the colored humate values are now in part or wholly bound to the silica and the return water is clarified. Furthermore, the eventual use of the tailings pile with the bound humate now permits reforestation.