Abstract: A method for recovering at least one precious metal from an aqueous solution containing the metal and particularly to recovery of silver and optionally one or more other precious metals from overflow of a sedimentation unit such as a thickener, a clarifier or a pond includes subjecting the aqueous solution to a micro and/or nanobubble flotation, wherein the pH of the aqueous solution is at most 1.5.

Abstract: A method for recovering at least one precious metal from an aqueous solution containing the metal and particularly to recovery of silver and optionally one or more other precious metals from overflow of a sedimentation unit such as a thickener, a clarifier or a pond includes subjecting the aqueous solution to a micro and/or nanobubble flotation, wherein the pH of the aqueous solution is at most 1.5.

Abstract: The invention relates to a method for treating a solution containing zinc sulphate, so that at least one of the rare metals such as indium, gallium and germanium can be separated from it. A portion of the metals to be separated can be precipitated from zinc sulphate solution by neutralizing the acidic solution and at least a portion is cemented by means of metal powder. The solid precipitates that are formed can be combined and treated subsequently in some suitable way to leach out the desired metals.

Abstract: The invention relates to the hydrometallurgical treatment of laterite ores in order to recover valuable metals. More specifically, the invention presented relates to a method for improving precipitation and solid-liquid separation in conjunction with the leaching of laterite ores. According to the method the slurry exiting the leaching of laterite ores is neutralized, after which part of the slurry is routed to solid-liquid separation. Iron is precipitated from the solid-liquid separation overflow by neutralizing the solution and the solution that is formed, which includes jarosite seeds, is routed to an appropriate point in the process to control the precipitation of iron and to enhance the filterability of the solids.

Abstract: The invention relates to a method for separating nickel and other valuable metals particularly from material having low nickel content, which contains iron and magnesium in addition to nickel and other valuable metals. The material having low nickel content is subjected to pulping and atmospheric leaching in acidic and oxidizing conditions, in which the majority of the metals in the material dissolve and the iron is partially precipitated. The precipitated iron is separated from the solution, after which nickel and the other dissolved valuable metals are precipitated as sulphides.

Abstract: The invention relates to a method for removing arsenic as scorodite from solutions that contain iron and arsenic. In accordance with the method, arsenic is first precipitated as ferric arsenate and subsequently processed hydrothermally into crystalline scorodite.

Abstract: The invention relates to a method for separating nickel and other valuable metalsparticularly from material having low nickel content, which contains iron and magnesium in addition to nickel and other valuable metals. The material havinglow nickel content is subjected to pulpingand atmospheric leaching in acidic and oxidising conditions, in which the majority of the metals in themate-rialdissolve and the iron is partially precipitated. The precipitated iron is sepa-rated from the solution, after which nickel and the other dissolved valuable metalsare precipitated as sulphides.

Abstract: The invention relates to a method for removing chloride from zinc sulphate solution in conjunction with zinc production. According to the method, the chloride is removed from solution by means of monovalent copper, which is produced in a separate copper(I) oxide formation stage, in which the pH is regulated to the region of 4.5-5.

Abstract: The invention relates to a method for treating a solution containing zinc sulphate, so that at least one of the rare metals such as indium, gallium and germanium can be separated from it. A portion of the metals to be separated can be precipitated from zinc sulphate solution by neutralizing the acidic solution and at least a portion is cemented by means of metal powder. The solid precipitates that are formed can be combined and treated subsequently in some suitable way to leach out the desired metals.

Abstract: The invention relates to a method for leaching a material containing a valuable metal and precipitating the valuable metal as a fine-grained powder by changing the electrochemical potential of an intermediary metal in the solution. In the leaching stage the intermediary metal or substance of the electrolyte solution is at a high degree of oxidation and in the precipitation stage another electrolyte solution is routed into the solution, in which the intermediary metal or substance is at a low degree of oxidation. After the precipitation stage the solution containing the intermediary is routed to electrolytic regeneration, in which part of the intermediary is oxidised in the anode space back to a high potential value and part is reduced in the cathode space to its low value.

Abstract: The invention relates to the hydrometallurgical treatment of laterite ores in order to recover valuable metals. More specifically, the invention presented relates to a method for improving precipitation and solid-liquid separation in conjunction with the leaching of laterite ores. According to the method the slurry exiting the leaching of laterite ores is neutralised, after which part of the slurry is routed to solid-liquid separation. Iron is precipitated from the solid-liquid separation overflow by neutralising the solution and the solution that is formed, which includes jarosite seeds, is routed to an appropriate point in the process to control the precipitation of iron and to enhance the filterability of the solids.

Abstract: The invention relates to a method for removing chloride from zinc sulphate solution in conjunction with zinc production. According to the method, the chloride is removed from solution by means of monovalent copper, which is produced in a separate copper(I) oxide formation stage, in which the pH is regulated to the region of 4.5-5.

Abstract: The invention relates to a method for leaching bulk concentrate of chalcopyrite-type by means of an aqueous solution containing sulphuric acid and an oxygen feed at atmospheric pressure and at a temperature between 75° C. and the boiling point of the solution. It is typical of the method that the particle size of the concentrate to be fed into leaching is in the region of 80% below 60-100 ?m and that the concentrate is leached with an aqueous solution, the acid concentration of which is regulated to be around 20-90 g/l.

Abstract: The invention relates to a method for removing arsenic as scorodite from solutions that contain iron and arsenic. In accordance with the method, arsenic is first precipitated as ferric arsenate and subsequently processed hydrothermally into crystalline scorodite.

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 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.

Abstract: The invention relates to a method for leaching a material containing a valuable metal and precipitating the valuable metal as a fine-grained powder by changing the electrochemical potential of an intermediary metal in the solution. In the leaching stage the intermediary metal or substance of the electrolyte solution is at a high degree of oxidation and in the precipitation stage another electrolyte solution is routed into the solution, in which the intermediary metal or substance is at a low degree of oxidation. After the precipitation stage the solution containing the intermediary is routed to electrolytic regeneration, in which part of the intermediary is oxidised in the anode space back to a high potential value and part is reduced in the cathode space to its low value.

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.