Elkem As

Elkem-spigerverket A/s

Jan H Torgersen

Norvald Gjelsvik

Ingleif Hundere

Gunnar Hannestad

A method of leaching of the metal contents in natural silicates by means of mineral acids to produce a metal-containing leaching liquid and a solid residue is disclosed. The silicate is first crushed but the grain size of substantially all of it is kept above 0.1 mm. It is then leached for a period of time sufficient to form a solid residue consisting chiefly of silica. The process is controlled so that the grains do not change in size or shape in the course of the leaching process. The silicate to be leached may be anorthosite or olivinrich rock and the solid residue from the leaching process may be utilized for building material, as a source for silicon in industrial processes, as a catalyst or carrier of catalysts or as an absorbent.

Method of acid leaching of silicates

Method of producing aluminiumchloride with a low content of magnesium from hydrochloric acid solutions which contain ions of aluminium and magnesium and from which the aluminiumchloride is precipitated by hydrochloric gas and where the precipitation is carried out continuously in cascade so that the major part of the aluminium will be precipitated from solutions in which the ratio between aluminium and magnesium calculated as g Al.sup.+3 /g Mg.sup.+2 is above 0,5. Produced aluminiumchloride may be transformed to aluminiumoxide by calcination.

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Skjetten, Norway

Jan H Torgersen