Elkem As

Einar Andersen

Bruno Ceccaroli

Roald Gundersen

Gunnar H Boe

The present invention relates to a method for recovering iron chloride, aluminum chloride and calcium chloride from silicon and ferrosilicon or from residues which contain silicon and/or ferrosilicon and metal chlorides and optionally copper and/or copper compounds, which materials are leached with HCl or HCl+FeCl.sub.3 /FeCl.sub.2 solutions, whereafter the solid silicon or ferrosilicon residue is removed from the leach solution and where any copper is removed from the leach solution. Fe.sup.2+ in the leach solution is oxidized to Fe.sup.3+ whereafter the leach solution is subjected to a liquid-liquid extraction by means of an organic phase containing n-tributyl phosphate dissolved in a hydrocarbon solvent in order to extract FeCl.sub.3 and at least a part of CaCl.sub.2 from the leach solution, stripping FeCl.sub.3 and any CaCl.sub.2 from the organic phase by water, concentrating the remaining solution by evaporation and adding HCl gas to the solution in order to selectively precipitate AlCl.sub.3.6H.sub.2 O from the solution and recovering AlCl.sub.3.6H.sub.2 O from the solution by filtration.

Method for recovering iron chloride, aluminum chloride and calcium

Copper content in sulphide-containing materials such as ores or concentrates is extracted by leaching the material by means of a leaching solution containing iron (III) chloride and copper (II) chloride, the leaching process being regulated in order to keep the red-ox potential in the leach solution between 430 mV and 460 mV, whereby iron (III) chloride is reduced to iron (II) chloride while copper (II) chloride is kept in the bivalent state. The copper content in the ore or concentrate is thereby leached as copper (II) chloride. Copper (II) chloride is thereafter extracted from the pregnant leach solution by contacting the solution with an organic complex-ion forming extractant which extraction properties are dependent on the chloride concentration.

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Kristiansand, Norway

Einar Andersen