Abstract: The invention relates to a method for recovering gold from a sulphidic concentrate, particularly one containing arsenopyrite and/or pyrite, hydro-metallurgically. The concentrate is first subjected to leaching with a concentrated solution of alkali chloride and copper (II) chloride, by means of which the copper minerals and some of the gold in the concentrate are made to dissolve. Elemental sulphur and precipitated iron and arsenic compounds are separated from the leaching residue using physical separation methods, whereby the first intermediate is obtained, which contains gold-bearing sulphide minerals and gangue minerals as well as the gold that remains undissolved. The free gold that remains undissolved is separated by means of gravity separation methods. After gravity separation, additional comminution is carried out, after which the sulphide minerals are decomposed and the gold-containing solution or residue is routed to the concentrate leaching circuit.

Abstract: The invention relates to a method for recovering gold from a sulphidic concentrate, particularly one containing arsenopyrite and/or pyrite, hydro-metallurgically. The concentrate is first subjected to leaching with a concentrated solution of alkali chloride and copper (II) chloride, by means of which the copper minerals and some of the gold in the concentrate are made to dissolve. Elemental sulphur and precipitated iron and arsenic compounds are separated from the leaching residue using physical separation methods, whereby the first intermediate is obtained, which contains gold-bearing sulphide minerals and gangue minerals as well as the gold that remains undissolved. The free gold that remains undissolved is separated by means of gravity separation methods. After gravity separation, additional comminution is carried out, after which the sulphide minerals are decomposed and the gold-containing solution or residue is routed to the concentrate leaching circuit.

Abstract: The invention relates to a method for controlling the reagent dosages in a concentration plant. In accordance with the method, a small part of the concentration plant feed is conducted to a side stream, where the feed is handle and variables required in dimensioning the reagent amount is measured. The reagent dosages of the main stream are determined according to the results obtained from the side stream.

Abstract: The present invention relates to a method of controlling the variation in content of minerals that float naturally in the feed of a concentration plant flotation circuit processing valuable minerals, such as minerals containing precious metals, copper-, nickel- and zinc-bearing minerals. After grinding, rough flotation is performed on minerals that float naturally, such as talc, into what is termed rough talc concentrate, which is then stored. The rough talc concentrate is fed into the valuable minerals flotation circuit as a pre-defined feed, and as a result the control of the flotation circuit is improved and reagent costs are substantially reduced.