Abstract: Stearic acid monoesters and diesters of polypropylene glycol (PPG), together with a hydrocarbon diluent, give exceptional defoaming performance in mineral processing streams over defoaming compositions made with esters of other fatty acids. The defoaming ability of compositions made from stearic acid esters of PPG is further enhanced by the inclusion of a relatively small amount of a non-ionic dispersing surfactant.

Abstract: A process of separating at least one mineral, e.g. silica, from an aqueous medium, e.g. one containing iron ore, by froth flotation using cationic alkyloxyalkaneamine collectors free of acrylonitrile is described. Alkyloxyalkaneamines free of acrylonitrile may be made by reacting an alcohol with an alkenenitrile having at least 4 to 13 carbon atoms. This process produces branching on the third carbon from the nitrogen of the resulting compound, e.g. 3-hexoxypentaneamine. In addition to the absence of acrylonitrile, the alkyloxyalkaneamines give better selectivity than some conventional etheramines.

Abstract: Dithiocarbonic acid, trithiocarbonic acid, water soluble salts of dithiocarbonic acid or trithiocarbonic acid or mixtures thereof when contacted with a mixed sulfide ore effectively depresses copper and iron sulfides thereby permitting molybdenite to be recovered by froth flotation. In copper concentrates produced by a flotation process, the organic collector reagents adhering to the surface of the copper and iron sulfides may be, and preferably are, stripped by conventional physical or chemical means prior to contacting the copper concentrate with the trithiocarbonate depressants of the invention. However, the trithiocarbonates of the invention have been found to be effective depressants of copper and iron sulfides in concentrates which are not stripped prior to treatment with the depressant.

Abstract: Copper is recovered from ores containing sulfidic copper minerals by forming the ore into a dump leach heap, and substantially saturating (i.e. thoroughly wetting) the ore in the heap with an aqueous strong acid solution containing 100 to 400 g/l H.sub.2 SO.sub.4 and 5 to 50 g/l ferric ion. The ore thus saturated is cured in contact with the strong acid solution for a curing period of at least 2 days, and generally from 5 days to 6 months or even longer, depending on the character of the ore and its permeability by the acid solution. The ore in the heap may be run of mine size, or may be coarsely crushed, again depending on permeability to the strong acid solution. After the curing period, the ore in the heap is washed by percolating through it a weak acid solution containing up to 50 g/l H.sub.2 SO.sub.4 and 5 to 50 g/l ferric ion. The wash solutions are collected and treated for copper recovery. Washing is continued until the copper content of the heap has been largely extracted.