Abstract: A hydrometallurgical process is described for recovery of precious metals from ores refractory to treatment by lixiviating agents by crushing the ore to no finer than a nominal 1/4 inch size, treating the ore with about 100% to about 300% of the stoichiometric amount of nitric acid required to react with the ore, maintaining the reaction mixture until the reaction is substantially complete, placing the treated ore in a permeable ore bed, washing the permeable ore bed to remove nitric acid, placing the washed ore in a heap permeable ore bed and passing a lixiviate solution for precious metals through the bed and recovering the dissolved precious metal from the lixiviate solution. All NOx gases generated during the reaction of nitric acid with the ore are recovered for conversion into nitric acid which is recycled for treating ore.

Abstract: A hydrometallurgical process is described for recovery of a precious metals from ores refractory to treatment by lixiviating agents by crushing the ore to no finer than a nominal 1/4 inch size, acidifying the ore with a mineral acid, treating the ore to a preliminary oxidation with nitric acid, optionally adding a binder to the oxidized ore, heap treating the ore with nitric acid to complete oxidation of the ore, water washing the heaped ore, optionally increasing the alkalinity of the heaped ore, heap treating the ore with a lixiviating solution and recovering precious metals from the lixiviating solution. The process recovers NO.sub.x gases generated during the preliminary oxidation and binder addition stage for conversion into nitric acid which is recycled for treating ore. Chemical treatments in the process can be carried out at ambient temperatures and atmospheric pressures.

Abstract: Particulate materials, particularly fine particles of clay animal litter, are agglomerated using a reticulated cellulose product formed by growing Acetobacter. Treatment with such reticulated cellulose also enhances the liquid absorbency of particulate materials.

Abstract: The invention resides in the use of a bacterial cellulose as a depressant for readily flotatable silicate minerals in an ore flotation process. Depending on the particular ore being treated, from 0.2-1.5 lb/ton of ore of the bacterial cellulose is effective as a talcose mineral depressant. Usually only about 0.10-0.25 lb/ton of the bacterial cellulose will produce optimum results.

Abstract: The present invention relates to an improved process for beneficiating an ore containing sulfide materials with selective rejection of pyrite, pyrrhotite and other metals and gangue. In particular, the process is useful for beneficiating ores and recovering copper from said ores. In one embodiment the process comprises the steps of(A) grinding the ore to an appropriate size range;(B) preparing a slurry comprising(B-1) said ground ore;(B-2) at least one collector which is a water-dispersible or soluble dihydrocarbyldithiodiphosphoric acid or salt having the formula ##STR1## wherein R.sup.1 and R.sup.2 are different hydrocarbyl groups containing up to about 12 carbon atoms, n is an integer equal to the valence of X and X.sup.n+ is a dissociating cation; and(B-3) water;(C) conditioning the slurry with SO.sub.2 under aeration at a pH of about 5.5 to about 7.

Abstract: A process for separating and recovering non-metallic minerals, particularly phosphate, from an ore containing non-uniform sized particles, including colloidal particles. The ore is slurried in an alkaline, aqueous solution with a dispersing agent. A flotation collector is added, and the mixture is contacted with a hydrophobic, high molecular weight, nonionic polymer to flocculate the fine particles and make them amenable to subsequent flotation. A second embodiment provides a process for the recovery of an upgraded non-metallic ore from ore slimes, such as phosphate slimes, utilizing a high molecular weight, polyacrylamide, anionic flocculating agent.

Abstract: A sequential flotation process for the recovery of high-grade concentrates of copper, lead and cobalt-nickel from sulfide ores is provided. A primary grind ore pulp is conditioned with SO.sub.2 as H.sub.2 SO.sub.3 under intense aeration, and the conditioned pulp subjected to sequential flotation, with regrinding and conditioning of a copper rougher concentrate obtained in the first flotation step for copper.

Abstract: Molybdenite is recovered by froth flotation of ore or concentrate by use of thio carboxylic acid compound and activated carbon to depress copper and other metal sulfides. The reagents are preferably utilized in a weight ratio of about 1:1.

Abstract: An improvement in the froth flotation separation of metallic sulfide mineral ores, particularly those ores bearing copper and molybdenum, in which a mercaptan collector is used in an earlier primary flotation stage, the improvement comprising the addition of activated carbon to achieve deactivation of the mercaptan collector prior to the component mineral separation stage, thereby providing enhanced separation of the minerals.