Abstract: The present disclosure broadly relates to a process for recovering magnesium as magnesium oxide and fibrous amorphous silica from serpentinite feedstocks. More specifically, but not exclusively, the present disclosure relates to metallurgical and chemical processes for recovering magnesium oxide and fibrous amorphous silica from serpentinite feedstocks. The process broadly comprises applying a sufficient amount of shear deformation force to the serpentine feedstocks to produce a particulate material of reduced size; subjecting the particulate material to magnetic separation to produce a primary magnetic separation product and iron-reduced tailings; and digesting the iron-reduced tailings into nitric acid, producing a magnesium-rich pregnant solution and insoluble solids. The process further comprises adjusting the pH of the pregnant solution to values ranging from about 5.0 to about 7.0.

Abstract: Process and apparatus for recovering magnesium from foundry sludge and cell bleed electrolytes includes structure and/or steps for: (i) dissolving, in a water slurry, soluble chloride compounds in the magnesium-containing material; (ii) acidifying the water slurry to between substantially pH 4 and substantially pH 6; (iii) further acidifying the water slurry to between substantially pH 1 and substantially pH 0, and providing a magnesium chloride solution; (iv) precipitating calcium from the magnesium chloride solution; (v) separating solids from the magnesium chloride solution; (vi) stripping SO2 from the magnesium chloride solution; and (vii) precipitating NaCl from the magnesium chloride solution to provide a concentrated magnesium chloride solution.

Abstract: The present invention is concerned with a process for extracting and recovering lead or lead derivatives in high purity from various materials containing lead sulphate, and particularly copper smelter flue dusts. The present process also allows the substantially complete recovery or recycling of precious metals otherwise lost in flue dusts wastes.