Abstract: Processing of mineral material containing precious metal with one or more sulfide minerals and non-sulfide gangue minerals including acid-consuming carbonate may include preparation of a sulfide concentrate by flotation with the flotation or conditioning prior to flotation using a gas comprising carbon dioxide. Flotation may be at an acidic pH without prior decomposition of the acid-consuming carbonate and may be without addition of acid for pH adjustment.

Abstract: Processing of mineral material containing precious metal with one or more sulfide minerals and non-sulfide gangue minerals including acid-consuming carbonate may include preparation of a sulfide concentrate by flotation with the flotation or conditioning prior to flotation using a gas comprising carbon dioxide. Flotation may be at an acidic pH without prior decomposition of the acid-consuming carbonate and may be without addition of acid for pH adjustment.

Abstract: A method of flotation processing ores and other mineral materials containing soluble nonferrous base metal and sulfide minerals involves dissolving the soluble nonferrous base metal and precipitating the soluble nonferrous base metal in the form of a floatable precipitate that is collected as part of a sulfide concentrate. The use of an oxygen-deficient flotation gas, such as nitrogen gas, promotes the precipitation of the floatable precipitate. A method for removing dissolved nonferrous base metal from solution involves contacting the solution with a particulate containing sulfide minerals under conditions promoting precipitation of the nonferrous base metal onto the sulfide mineral.

Abstract: Provided is a method involving flotation of a feed of platinum group metal ore material to prepare a platinum group metal concentrate during mineral processing operations. Prior to and/or during the flotation, a lead-containing activator reagent and a xanthate collector reagent are added to the slurry and during the flotation, an oxygen-deficient flotation gas, such as nitrogen gas, is used.

Abstract: A method for the treatment of sulfide ores containing silver by pressure oxidation. The method includes the addition of a sulfate-binding material to reduce the formation of jarosite species during pressure oxidation. Silver can then be recovered from the solids portion of the discharge slurry. A jarosite reduction step, such as by a lime boil, that is typically required to recover silver after pressure oxidation can advantageously be eliminated.

Abstract: Provided is a method involving flotation of a feed of platinum group metal ore material to prepare a platinum group metal concentrate during mineral processing operations. Prior to and/or during the flotation, a lead-containing activator reagent and a xanthate collector reagent are added to the slurry and during the flotation, an oxygen-deficient flotation gas, such as nitrogen gas, is used.

Abstract: A method for the treatment of sulfide ores containing silver by pressure oxidation. The method includes the addition of a sulfate-binding material to reduce the formation of jarosite species during pressure oxidation. Silver can then be recovered from the solids portion of the discharge slurry. A jarosite reduction step, such as by a lime boil, that is typically required to recover silver after pressure oxidation can advantageously be eliminated.

Abstract: A method is provided for flotation of refractory auriferous sulfide using an oxygen-deficient flotation gas. The method is particularly suited for non-selective flotation of different iron-containing sulfide mineral species. Comminution prior to flotation may be performed in an oxygen-deficient environment.

Abstract: Provided is a method for treating refractory gold-bearing ores that have both sulfide material with which the gold is associated and from which the gold is difficult to separate and having organic carbonaceous material having an affinity for at least one of gold and a gold complex. The mineral material is pressure oxidized in the presence of a halogen-containing material in a manner to reduce the susceptibility of the organic carbonaceous material to capture and hold gold during the pressure oxidation. Also provided is a gold-bearing effluent product from the pressure oxidation process. The effluent product comprises gold which can be effectively recovered by carbon-in-leach cyanidation of the effluent product. In many cases, gold recovery according to the present invention is increased substantially over standard pressure oxidation techniques.

Abstract: Provided is a method for processing a gold-bearing sulfide ore which involves maintaining the ore in a substantially oxygen free environment, preferably beginning with comminution of the ore and ending when a desired final concentrate, enriched in sulfide minerals, is obtained by flotation. In one embodiment, nitrogen gas is used to substantially prevent contact between the ore and air during comminution of the ore and during flotation operations. It is believed that oxygen gas present in air detrimentally affects the recovery of sulfide minerals in a flotation concentrate through surface oxidation of sulfide mineral particles. The use of a gas such as nitrogen can significantly reduce the potential for such surface oxidation.

Abstract: Provided is a method for processing a gold-bearing sulfide ore which involves maintaining the ore in a substantially oxygen free environment, preferably beginning with comminution of the ore and ending when a desired final concentrate, enriched in sulfide minerals, is obtained by flotation. In one embodiment, nitrogen gas is used to substantially prevent contact between the ore and air during comminution of the ore and during flotation operations. It is believed that oxygen gas present in air detrimentally affects the recovery of sulfide minerals in a flotation concentrate through surface oxidation of sulfide mineral particles. The use of a gas such as nitrogen can significantly reduce the potential for such surface oxidation.

Abstract: A process for recovering precious metals from a refractory ore by forming a slurry which is heated to a temperature in excess of about 150.degree. C. at an oxygen partial pressure in excess of about 10 psia for an effective amount of time to form a partially oxidized slurry which is then subjected to carbon-in-leach treatment to separate the precious metals.

Abstract: A froth flotation method for the separation of trona from ground trona ore slurried in a saturated brine solution of sodium carbonate and sodium bicarbonate by using organic compounds of a specified type as flotation collectors.