Abstract: A method for selectively extracting metal values from manganese bearing ores such as marine nodules. The ore is initially leached to solubilize manganese and other desirable metals as nitrates. The resulting solution is then treated with manganous hydroxide to selectively precipitate metals such as copper, nickel and cobalt. The enriched mixture of metal hydroxides is separated from the manganese nitrate solution, which is decomposed to recover high purity MnO.sub.2.

Abstract: Silver and gold are selectively recovered from cyanide solutions by addition of lime, and precipitation of the silver as sulfide by means of sodium sulfide, followed by electrowinning of gold from the filtrate.

Abstract: A process for the treatment of nickel-copper concentrates comprises the steps of leaching nickel selectively with a dilute hydrochloric acid solution, separating the leach solution from the residue, roasting the residue at a temperature sufficient to form at least about the stoichiometric quantity of sulphate to convert all the nickel present in the residue to nickel sulphate, leaching the roasted residue with water and precipitating any dissolved copper from the aqueous leach solution thus obtained.

Abstract: A process for recovery of zinc values contained in thermally activated iron containing copper and zinc sulfides in which said activated sulfides have been subjected to an acid leach in aqueous sulfuric acid to produce a solution of ferrous sulfate and a solids residue containing copper and zinc values. The solids residue containing copper and zinc values is reacted with an acidic copper sulfate solution to precipitate copper values as a simple copper sulfide with concurrent dissolution of iron and zinc values to form a solution of ferrous sulfate containing said dissolved zinc values and said solution of ferrous sulfate is separated from the simple copper sulfides and reacted with H.sub.2 S for precipitation of zinc values therefrom as zinc sulfide. Any nickel and cobalt values present in said activated sulfides is dissolved in said solution of ferrous sulfate and reacted with the H.sub.2 S at elevated temperature for selective precipitaton.

Abstract: Metal values are extracted from manganiferous ocean floor nodule ore by treating the ore with hydrochloric acid, thereby producing chlorine and a starting pulp containing a solution of the metal chlorides and a solid residue. The starting pulp is subjected to at least two subsequent acidifications with HCl, each acidification being followed by addition of fresh ore, thereby producing chlorine and a final pulp containing a concentrated solution of metal chlorides and a solid residue. The solid residue is separated from the concentrated solution and substantially all the metal values, except manganese and alkali and alkaline earth metals, are separated from the solution. The manganese is separated from the solution by treatment with chlorine, at least the major portion of which was produced in the preceding leaching steps, while maintaining the solution at a pH of between about 3 and 7 by addition of a neutralizing agent such as MgO or Mg(OH).sub.2 whereby the manganese is precipitated in the form of MnO.sub.

Abstract: This invention relates to a process for hydrometallurgical treatment of concentrates of sulphides of copper, nickel, cobalt, lead and iron and copper-containing mattes. A first embodiment of the process includes subjecting a finely ground slurry of a sulphide concentrate to an oxidation leach at elevated temperature and pressure in the presence of an oxygen-bearing gas to preferentially leach cobalt and nickel and to convert galena to lead sulphate. The reaction mixture is heated to a further elevated temperature, in the absence of oxygen, to convert a portion of chalcopyrite to insoluble simple copper sulphides and ferrous sulphate solution and to decompose complex insoluble ferric compounds. The resulting mixture is subjected to differential flotation whereby a lead concentrate and a copper concentrate are obtained.

Abstract: The process of sulfidizing an acid copper leach pulp prior to flotation recovery of the copper therein comprising adding to and admixing with said pulp in a reaction zone an ionizable sulfide material, said sulfide material being added in an amount proportional to the amount of copper passing through said zone so that the sulfidization reaction is completed within about 30 seconds and the pulp leaving said zone has an aqueous copper concentration of from about 0.014 to 0.024 gram per liter and a reactor for such process comprising elongated tubular means, shaft means mounted in said tubular means, and a plurality of blade members attached to said shaft, said blade members being spaced along said shaft at approximately 30.degree. pitch angles relative to the axial direction of the shaft and there being a reverse pitch direction of a certain of said blades at predetermined distances along the length of said shaft.

Abstract: A hydrometallurgical process for treating iron containing metal sulfides for rendering iron and non-ferrous metal values active and amenable for selective extraction and separate recovery. Sulfur values can be controllably produced as elemental sulfur or as sulfuric acid to supply acid requirements of the process, while substantially obviating the discharge of sulfur-containing gases to the atmosphere. Ores and concentrates of the sulfides are thermally activated by sequentially heating and reducing said sulfides in a countercurrent flow of heating and reducing gases respectively in a reactor whereby the reaction products of the reducing gas and sulfides, together with liberated labile sulfur, are controllably combusted with oxygen to satisfy heat requirements of the thermal activation process and to convert sulfur values to SO.sub.2 gas. The activated sulfides are subjected to an acid leach in aqueous sulfuric acid for production of ferrous sulfate and evolution of H.sub.

Abstract: Copper is recovered from chalcopyrite by means of a pollution-free hydrometallurgical process which entails leaching and converting the chalcopyrite with copper sulfate in order to produce an insoluble copper sulfide, a soluble iron sulfate and sulfuric acid. A secondary leach is then conducted in order to react the copper sulfide with oxygen in the presence of a jarosite-forming cation to produce a soluble copper sulfate and an insoluble iron bearing jarosite. This copper sulfate is separated from the jarosite and sent to a copper recovery process and/or recycled. Alternatively, the copper sulfide from the initial leach may be separated from the iron sulfate solution immediately after the initial leach, and this copper sulfide can be treated with other processes to produce elemental copper and sulfur.