Abstract: A method for roasting sulphide ores or ore concentrates containing precious metals is practiced in a furnace, typically in a fluidized bed. The ore and a sulphur-binding lime-containing material are supplied to a roasting furnace in which the ore is roasted with the emission of heat and sulphur dioxide. The lime-containing material--such as calcium hydroxide--is mixed into the cooling water for the roasting furnace and sprayed into the furnace as a lime-containing aqueous slurry. Roasting occurs at about 600-850.degree. C. (e.g. 650-750.degree. C.).Roasted material is discharged from the furnace and acted upon to recover gold, silver and copper metal.

Abstract: The invention relates to a method of improving the heat recovery in a waste head boiler, in which gas, produced in high-temperature processes and containing molten and/or solid particles and/or evaporated components, is cooled. In a waste heat boiler, a slowly cooling zone, i.e. a hot "tongue" is generally formed in the gas flow. To improve the cooling of the hot "tongue", gas and/or solid particles and/or vaporizing liquid, such as circulating gas or circulating particles separated from the process and cooled, are introduced into the hot zone or "tongue".

Abstract: Method and apparatus for producing matte and/or metal from sulphidic fine-grained ore or ore concentrate. The ore or ore concentrate is smelted in a flame chamber in such a way that at least part of the solid material in the flame chamber melts and flows downward into a smelt bath furnace, on top of which the flame chamber is disposed. Volatile metallic and sulphuric components are conducted upward from the flame chamber to a fluidized bed reactor to be utilized as fluidizing gas, the gases being rapidly cooled down in the fluidized bed.

Abstract: A method and apparatus for producing, in a reactor, a suitable prereduced product for final reduction from material containing metal oxide. The material is preheated in a fluidized bed by means of hot gases from a subsequent prereduction stage. The hot material is smelted and prereduced in a flame chamber utilizing hot reducing gases from a subsequent final reduction stage. The prereduced material is completely reduced in the final reduction stage.

Abstract: Lead in separated from a sulfidic concentrate by feeding a finely-divided concentrate, a silicate-high slagging agent, and air or oxygen-enriched air into the upper section of a suspension reaction shaft of a flash-smelting furnace in order to form a suspension and to oxidize the lead to lead oxide, by removing the gases via a riser pipe of the furnace and by discharging melt from a lower furnace of the flash-smelting furnace for further treatment. The slagging agent is fed at such a rate that substantially all of the melt is of the slag type and that all of the melt withdrawn from the lower furnace is directed to a reduction stage in order to reduce the lead silicate and to separate it as raw lead.

Abstract: Lead in separated from a sulfidic concentrate by feeding a finely-divided concentrate, a silicate-high slagging agent, and air or oxygen-enriched air into the upper section of a suspension reaction shaft of a flash-smelting furnace in order to form a suspension and to oxidize the lead to lead oxide, by removing the gases via a riser pipe of the furnace and by discharging melt from a lower furnace of the flash-smelting furnace for further treatment. The slagging agent is fed at such a rate that substantially all of the melt is of the slag type and that all of the melt withdrawn from the lower furnace is directed to a reduction stage in order to reduce the lead silicate and to separate it as raw lead.The transversal cross section of the lower furnace is preferably substantially circular.

Abstract: A suspension smelting furnace is disclosed for the suspension smelting of finely-grained oxide or sulfide ores and concentrates, and provided with a horizontal lower furnace to which have been connected the lower ends of at least one vertical suspension reaction zone and rising flow zone, with devices at the upper end of the suspension reaction zone for the production of a suspension of finely-grained oxide and sulfide ores or concentrates with air and oxygen, and for feeding this suspension downwards in the reaction zone at the lower end of which there are optionally means for the sulfidization or reduction of the suspension, and in the lower furnace under the suspension reaction zone there is the main smelt reaction zone in which the bulk of the suspension dissolves vertically in the smelt accumulated in the lower furnace main reaction zone, and in the rising-flow zone there are devices for removing the remaining suspension at its upper end.