Abstract: A process to increase the content of germanium which is found in an iron hydroxide phase of an ore of the supergene type for later recovery by solvent extraction. The process comprises the steps of first crushing the ore, converting the ore to pulp, and then subjecting the pulp to a magnetic separation to give a magnetic fraction enriched in germanium. Also, the process can be used to increase the content of gallium which is found in a jarosite phase of an ore of the supergene type for later recovery by solvent extraction.

Abstract: The invention relates to a process for upgrading andalusite present in an ore containing it. The process involves separation from other silicates by froth flotation to obtain a concentrate whose content of andalusite is higher than 90%. It is characterized by the fact that the process comprises at least the following steps:(a) grinding as may be required and placing in pulp of the ore containing the andalusite(b) pre-conditioning the ore containing the andalusite by keeping the pH of the aqueous phase of the pulp at a value of below 3.50, the solids ratio in the pulp being higher than 30% (by weight)(c) conditioning the preconditioned ore pulp for at least 10 minutes after addition of an alkyl sulfonate;(d) dilution as may be required of the pulp to bring it to a solids ratio comprised between 15 and 30% (by weight);(e) froth flotation by bubbling calibrated air bubbles therethrough in manner known in itself, the froth flotation proper lasting at the most 10 minutes.

Abstract: The invention relates to a process for recovering silver in sulfuric solutions. Its characterizing feature is that the silver solution is contacted with a quantity of zinc sulfide which is at least equal to the stoichiometric quantity and the surface area of which is at least equal to K Ag.sup.2/3 x V, K being a constant, Ag being the silver concentration in the solution expressed in kilograms per cubic meter, and V the volume of the solution in cubic meters, the surface area being expressed in square meters and the value of K being greater than or equal to approximately 10. Application to the recovery of silver in zinc plant residues.

Abstract: This invention provides a process for the beneficiation of phosphate ores having a magnesia-rich carbonate-containing gangue and a silica-containing gangue, which process comprises subjecting the phosphate ore particles to controlled attrition to remove at least a portion of the magnesia-rich carbonate-containing gangue; and subjecting the phosphate ore resulting from attrition to a plurality of flotations to remove the remaining magnesia-rich carbonate-containing gangue and the silica-containing gangue and to recover a concentrated phosphate product, the flotations including sequentially a phosphate flotation, a silica flotation and a carbonate flotation. Alternatively, the controlled attrition can be employed after the silica flotation and prior to the carbonate flotation.

Abstract: A process of upgrading garnieritic ores, oxidized nickelifer ores of lateritic origin which includes subjecting the ore to controlled attrition and classifying particles so formed according to their size, those having a dimension smaller than a predetermined value being recovered.

Abstract: The invention provides a process for the preconcentration of metalliferous values contained in metal-bearing ore materials (ores and byproducts thereof) and involves subjecting the ore material to careful attrition to obtain a particle mixture of fine and coarse particles, separating the fine particles from the coarse particles by granulometry, and recovering from the thus-separated fine particles a cut having a particle size not exceeding about 50 microns and containing the metalliferous values in concentrated form.