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 present invention relates to a method for the treatment of copper-bearing materials, such as copper concentrates, so that the impurities and gangue minerals in the materials, such as silicates, are in effect removed completely.

Abstract: The invention is a novel process arrangement for producing pure zinc chemicals from the minor flow of a calcining-dissolving-electrolysis type of a preparation process of zinc. The invention is based on the fact that part of the production of the zinc sulphate-containing solution obtained from the dissolution of the calcining-dissolving-electrolysis plant is directed to the preparation of zinc chemicals. The actual recovery process of zinc, which is based on electrolysis, is not disturbed, as only part of the production of the zinc sulphate solution is directed to the preparation of zinc chemicals. The extraction process is based on the use of any organically substituted phosphoric acid or organically substituted thiophosphinic acid. The strong acid solution, which is generated as a by-product in the extraction process of zinc, is recycled back to the calcining-dissolving-electrolysis type of a preparation process of zinc.

Abstract: The invention relates to a method for processing concentrates, particularly concentrates produced from copper sulfide-based ores. According to the method, the concentrate (4) to be processed, obtained from ore concentration, is divided into two parts, to a concentrate (7) mainly containing poorly soluble components, and to a concentrate (8) mainly containing well soluble components. The concentrate (8) containing well soluble components is conducted to a leaching step (9), and the solution (13) obtained from said leaching step is conducted to at least one conversion step (11, 16), and to the conversion step (11) that is located first in the flowing direction, there is fed the concentrate (7) containing poorly soluble components.

Abstract: The invention relates to a method for smelting sulfidic copper concentrates, in which method copper sulfide bearing material is smelted in a smelting furnace (1) for creating blister copper and slag. According to the method, at least part (3) of the feed of the smelting furnace (1) is copper sulfide bearing (3) material obtained by means of sulfide bearing material (2) that is fed into the hydrometallurgic further processing (12,19) of slag (11) created in the smelting process.

Abstract: The invention relates to a method for controlling the partial pressure of oxygen when mutually separating minerals in the different process steps of the separation process. In order to control the partial pressure of oxygen, the gases fed in the different process steps are recirculated in an essentially closed gas circulation created around the equipment used in the different process steps, so that the gas recirculation is controlled by measuring the potential of the slurry containing valuable minerals.