Abstract
IN the preparation of clean mineral from crude ore, the processes of water concentration and flotation concentration, in combination or separately, achieve all that is required with sulphide ores, the former process being particularly successful in the recovery of coarse and granular mineral, while flotation is equally successful with fine and with the finest mineral. But, with oxide or oxidised ores, though water concentration will generally suffice where the mineral grain is large and remains so during crushing, there is no equivalent of flotation to recover fine mineral or that so fine as to go into suspension. Yet in the dressing of tin and other oxide ores requiring fine crushing, a substantial proportion of the ore passes into the fine condition described as slime, from which it is at present impossible to make a satisfactory mineral recovery. Again, the recovery of the vanadium mica, roscoelite, from the sandstone in which it occurs typically in the United States is not at present possible by any dressing process, because the roscoelite is friable and light; such vanadium deposits, large as they are, at present lie idle. Even where the mineral grain is sufficiently large it sometimes happens, and particularly with minerals of the rare metals, that water concentration will yield a complex concentrate of two or more minerals with properties of density, magnetic per-jneability, electric conductivity, etc., so similar that no one of the presently applied methods of dressing is effective in separation. Thus, some vanadium, uranium, and molybdenum minerals occurring together largely remain inseparable; and some alluvial tin concentrates contain rare minerals from which it is difficult to free the tin.
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TRUSCOTT, S. Dielectric Mineral Separation. Nature 114, 793–794 (1924). https://doi.org/10.1038/114793a0
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DOI: https://doi.org/10.1038/114793a0