Elkem As

Elkem Asa

Roald Gundersen

Ragnhild Jensen

Bruno Ceccaroli

Inger J Eikeland

Einar Andersen

Inger Johanne Eieland

The present invention relates to a method for upgrading silicon-containing solid residues obtained after leaching of copper from copper-containing residues from direct synthesis of organochlorosilanes. Solid residue, optionally together with an oxidation agent, is supplied to a smelting furnace where the residues are melted and form a molten metallic phase substantially containing silicon and a calcium silicate slag and tapping of the molten metallic phase and an inert slag from the smelting furnace.

Method for upgrading of silicon-containing residues obtained after

Method for treatment of residues from organochlorosilane and/or

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

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Vennesla, Norway

Roald Gundersen