Abstract: A process for extracting metal values from sea nodules is provided in which nickel, cobalt and copper values are selectively extracted by leaching raw sea nodules in an aqueous ammoniacal medium in the presence of a reducing agent for tetravalent manganese and carbonate to precipitate the reduced manganese as manganous carbonate.

Abstract: A process which enables cumulative recovery of nonferrous metal values from manganiferous sea nodules and a limonitic ore comprises treating the limonitic ore in an aqueous acidic medium under reducing conditions to extract nonferrous metals and iron from the ore and form a solution containing ferrous iron and then leaching the sea nodules with such solution to extract nonferrous metals from the sea nodules and precipitate a predominant amount of the iron as hydrated ferric oxide.

Abstract: A process is provided for extracting iron values as soluble ferrous salts from a limonitic ore which comprises leaching the ore in an acidic medium in the presence of a reducing agent, the reducing agent being a sulfide. Non-ferrous metal values are also extracted from the ore and they may be selectively separated from the solubilized iron salts.

Abstract: A process for extracting metal values from manganiferous sea nodules is provided in which nickel, copper, and cobalt values are selectively leached in a sulfuric acid medium in two stages, the first stage being effected at a temperature up to about 100.degree. C and to a final pH of not less than about 1.5 and the second stage being effected at a temperature of about 160.degree. C to about 260.degree. C and at an initial pH of not less than about 1.5.

Abstract: This invention provides a novel and an improved hydrometallurgical method for recovering copper values from copper concentrates. The method essentially comprises the following steps:A. forming an aqueous leach solution containing chloride or bromide ions in a predetermined concentration;B. dispersing copper concentrates in such leach solution to form a slurry;C. carrying out the leaching operation of the slurry at an elevated temperature and under an overpressure of oxygen so as to transform a major proportion of the copper values present in the concentrates into a solid basic copper sulphate;D. separating the resulting leach residue containing the basic copper sulphate from the leach solution; andE. recovering the copper values from the obtained leach residue.The process is simple and efficient and can be carried out either batchwise or continuously.

Abstract: Sulfate solutions containing at least one valuable metal from the group: Fe, Ni and Co, particularly solutions resulting from the leaching of lateritic ores or concentrates, are treated to recover the valuable metal. The latter is precipitated by treating the solution with magnesium hydroxide. The resulting magnesium-containing solution is treated with lime under controlled conditions to precipitate relatively fine particles of magnesium hydroxide and relatively coarse particles of gypsum. The difference in particle size is relied on to separate the magnesium hydroxide (for recycling) from the gypsum (which is calcined to regenerate lime).