Abstract: A process for recovery of gold from gold-containing raw materials includes obtaining gold-containing raw material having refractory gold-containing sulfidic minerals including a first type of refractory sulfidic mineral having high gold content and a second type of sulfidic mineral having low gold content; forming a mineral pulp including a first type of refractory sulfidic mineral particles having high gold content and second type of sulfidic mineral particles having low gold content by suspending ground gold-containing material in water and optionally further milling the material; conditioning the mineral pulp by addition of a surface modifying chemical to obtain a conditioned pulp; subjecting the conditioned pulp to a froth flotation process; recovering the non-floatable first type of refractory sulfidic mineral particles having high cold content as flotation tailings; pressure oxidizing (POX) the flotation tailings to obtain a discharge slurry comprising liberated gold; and recovering gold from the discha

Abstract: A process for recovery of gold from gold-containing raw materials includes obtaining gold-containing raw material having refractory gold-containing sulfidic minerals including a first type of refractory sulfidic mineral having high gold content and a second type of sulfidic mineral having low gold content; forming a mineral pulp including a first type of refractory sulfidic mineral particles having high gold content and second type of sulfidic mineral particles having low gold content by suspending ground gold-containing material in water and optionally further milling the material; conditioning the mineral pulp by addition of a surface modifying chemical to obtain a conditioned pulp; subjecting the conditioned pulp to a froth flotation process; recovering the non-floatable first type of refractory sulfidic mineral particles having high cold content as flotation tailings; pressure oxidizing (PDX) the flotation tailings to obtain a discharge slurry comprising liberated gold; and recovering gold from the discha

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: A method for recovering valuable metals, such as lead, silver and gold from the residue of an electrolytic zinc process, wherein the residue from the zinc process is suspended and sulfidized for converting the lead and silver compounds into sulfidic form, and further flotated for forming a flotation concentrate that contains valuable metals, wherein the sulfidizing and flotation processes are controlled electrochemically, so that the content of the sulfide ions fed in the sulfidizing stage is adjusted by means of the redox potential to a level where the grain size of the created valuable metal sulfides is sufficient for flotating them, and that the redox potential of the flotation stage is adjusted to be within a range where the collector chemical is adhered to the mineral to be flotated, but the sulfides are not oxidized.

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 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: 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.