Abstract: Sulphidic zinc concentrate usually also includes small amounts of rare metals such as indium and gallium. If the content of these metals in the raw material is sufficiently high, their recovery may be economically worthwhile. In the method according to the invention the recovery of indium and other desirable rare metals takes place in a zinc leaching process, in which at least part of the sulphidic concentrate is leached directly without roasting.

Abstract: The invention relates to a method for the leaching of oxidized ores and in particular zinc ores. The ore, wherein the valuable metals are at least partially in silicate form, are routed to an acidic leaching stage in conditions where the silicate decomposes and the valuable metal ion comes into the solution. During leaching the silicate ion first dissolves, but simultaneously decomposes and is precipitated as silica.

Abstract: Sulphidic zinc concentrate usually also includes small amounts of rare metals such as indium and gallium. If the content of these metals in the raw material is sufficiently high, their recovery may be economically worthwhile. In the method according to the invention the recovery of indium and other desirable rare metals takes place in a zinc leaching process, in which at least part of the sulphidic concentrate is leached directly without roasting.

Abstract: The invention relates to a method for the hydrolytic precipitation of iron as jarosite from a sulphate-containing solution in connection with zinc recovery from zinc calcine. The recovey contains neutral leach, ferrite leach, zinc electrolysis and iron precipitation stages. The ferrite included in the calcine is leached with return acid of the electrolysis after which the iron present in ferrous form is neutralized and routed to an iron precipitation stage, where the iron is oxidised to the trivalent form using an oxygen-containing gas. Also present in the precipitation stage arc Na, K or NH4 ions and jarosite nuclei.

Abstract: The invention relates to a method for the precipitation of nickel from an aqueous solution containing its sulphate as a metallic powder suitable as an alloying element for refined steel. In this method, nickel reduction takes place continuously in one or several autoclaves at a temperature of 80-180 ° C. and hydrogen pressure of 1-20 bar, whereby the production capacity can be raised significantly, compared to batch processes made in correspondingly dimensioned devices or equipment.

Abstract: The invention relates to a method for the leaching of oxidized ores and in particular zinc ores. The ore, wherein the valuable metals are at least partially in silicate form, are routed to an acidic leaching stage in conditions where the silicate decomposes and the valuable metal ion comes into the solution. During leaching the silicate ion first dissolves, but simultaneously decomposes and is precipitated as silica.

Abstract: The invention relates to a method for the hydrolytic precipitation of iron from a sulphate solution as jarosite. A sulphate-containing solution, with iron present in divalent form, is routed to an iron precipitation stage, where the iron is oxidised to the trivalent form using an oxygen-containing gas. Also present in the precipitation stage are Na, K or NH4 ions and jarosite nuclei.

Abstract: The invention relates to a method for the precipitation of nickel from an aqueous solution containing its sulphate as a metallic powder suitable as an alloying element for refined steel. In this method, nickel reduction takes place continuously in one or several autoclaves at a temperature of 80-180° C. and hydrogen pressure of 1-20 bar, whereby the production capacity can be raised significantly, compared to batch processes made in correspondingly dimensioned devices or equipment.

Abstract: The invention relates to a method for the precipitation of nickel from its aqueous solution as a metal powder using hydrogen. The aqueous solution containing nickel compounds is neutralised first with an earth alkali or alkali compound so the nickel precipitates as nickel hydroxide or as an alkaline salt, after which reduction is performed in the presence of a catalyst in ion form in atmospheric or close to atmospheric conditions preferably as a continuous process.

Abstract: The invention relates to a method for leaching zinc concentrate in atmospheric conditions in the presence of trivalent iron. It is essential that the zinc concentrate is fed into conditions where in addition to trivalent iron, there are also jarosite nuclei. The sulfuric acid content of the leaching step is maintained within the region 10-40 g/l, and the temperature within the region 80° C.—the solution boiling point, and into the leaching step there is fed oxygen, so that the zinc concentrate is dissolved and the iron is precipitated as jarosite.

Abstract: The invention relates to a method for leaching sulfidic nickel matte and particularly copper rich nickel matte, as well as for leaching said matte together with a metallic copper and/or copper-nickel matte. The leach of nickel matte is carried out as pressure leach in one or several stages by means of copper sulfate.

Abstract: The invention relates to a process for leaching nickel and copper from nickel-copper matte formed in pyrometallurgical nickel production by means of a multi-stage process. It is essential of the invention that the leaching of nickel takes place in at least two stages in conditions where free sulfuric acid is essentially absent, and that in these stages, the leaching of the nickel content of the matte is mainly carried out with copper as the oxidizer.