Salt components of dross can be extracted efficiently through evaporation. During dross treatment, temperatures can be permitted to approach or exceed the boiling point of one or more salt components of the dross, preferably in an oxidizing environment. The temperature can be held sufficiently high such that the salt content can exert an appreciable vapor pressure and can be held for a sufficient time to permit most, all, or substantially all of the salt content to evaporate and be carried away from the kiln in combustion gasses. The evaporated salt can be condensed and collected.

Salt components of dross can be extracted efficiently through evaporation. During dross treatment, temperatures can be permitted to approach or exceed the boiling point of one or more salt components of the dross, preferably in an oxidizing environment. The temperature can be held sufficiently high such that the salt content can exert an appreciable vapor pressure and can be held for a sufficient time to permit most, all, or substantially all of the salt content to evaporate and be carried away from the kiln in combustion gasses. The evaporated salt can be condensed and collected.

There is provided a method for recovering PGM, in which at least one base metal oxide selected from a group consisting of copper oxide, iron oxide, tin oxide, nickel oxide and lead oxide is added to and melted in a molten slag, and a PGM alloy contained in the molten slag is recovered.

There is provided a method for recovering PGM, in which at least one base metal oxide selected from a group consisting of copper oxide, iron oxide, tin oxide, nickel oxide and lead oxide is added to and melted in a molten slag, and a PGM alloy contained in the molten slag is recovered.

The invention belongs to the technical field of the resource treatment of industrial wastes, and particularly relates to a method for preparing a cementing material using smelting industrial waste slag after utilizing the simultaneous removal of SO.sub.2 and NO.sub.x in flue gas and an application of the cementing material obtained by the same. According to the invention, SO.sub.2 and NO.sub.x in the flue gas can be treated with the smelting industrial waste slag, meeting requirement of flue gas desulfurization and denitration; moreover, the smelting industrial waste slag can be purified and separated by means of waste gas resources to obtain a cementing material, realizing the resource utilization of the smelting industrial waste slag and waste gas.

The invention belongs to the technical field of the resource treatment of industrial wastes, and particularly relates to a method for preparing a cementing material using smelting industrial waste slag after utilizing the simultaneous removal of SO.sub.2 and NO.sub.x in flue gas and an application of the cementing material obtained by the same. According to the invention, SO.sub.2 and NO.sub.x in the flue gas can be treated with the smelting industrial waste slag, meeting requirement of flue gas desulfurization and denitration; moreover, the smelting industrial waste slag can be purified and separated by means of waste gas resources to obtain a cementing material, realizing the resource utilization of the smelting industrial waste slag and waste gas.

An environmentally friendly (e.g. no acid, base, or cyanide) system and process for large scale extraction of metal ion into aerobic molten salt (or ionic liquid) and the electrodeposition of metal (e.g. copper, gold, silver, etc.) from the metal ion dissolved in the molten salt. The non-volatile low vapor pressure liquid salt is reusable, and heat from the molten slag can heat the molten salts or ionic liquids. Another embodiment comprises a one-pot apparatus for the extraction of metal (e.g. copper) from metal earths and electrodepositing the metal using a low melting (209° C.) aerated Na—K—Zn chloride salt in which copper metal oxidizes and is converted to soluble copper chloride. When an electrical power supply is connected to the graphite vessel (cathode) and to copper rods in the melt (anodes), then the copper chloride is deposited as copper metal by electroreduction on the bottom of the graphite reaction vessel.

An environmentally friendly (e.g. no acid, base, or cyanide) system and process for large scale extraction of metal ion into aerobic molten salt (or ionic liquid) and the electrodeposition of metal (e.g. copper, gold, silver, etc.) from the metal ion dissolved in the molten salt. The non-volatile low vapor pressure liquid salt is reusable, and heat from the molten slag can heat the molten salts or ionic liquids. Another embodiment comprises a one-pot apparatus for the extraction of metal (e.g. copper) from metal earths and electrodepositing the metal using a low melting (209° C.) aerated Na—K—Zn chloride salt in which copper metal oxidizes and is converted to soluble copper chloride. When an electrical power supply is connected to the graphite vessel (cathode) and to copper rods in the melt (anodes), then the copper chloride is deposited as copper metal by electroreduction on the bottom of the graphite reaction vessel.

A two stage dross treatment capable of being performed in a single reaction vessel is disclosed. Dross, especially white dross, can be contacted with salt flux in a rotary furnace to recover metal from the dross. This first stage can recover metal during the conversion of white dross and salt flux to salt cake. In a second stage, the furnace can be raised to a sufficiently high temperature to evaporate the salt content of the salt cake, allowing the evaporated salt to exit the furnace and be separately condensed and collected. The result of the second stage is collected salt and salt-free oxides. After removing the salt-free oxides, residual heat in the furnace and collected salt can be used for a subsequent dross treatment.

The present invention is a CO.sub.2 based hydrometallurgical multistage reaction and separation system comprising: a pre-washing device configured to fully mix the feedstock, such as industrial solid waste, mineral and mine tailings with auxiliary reagents and water at specific ratio, a reactor configured to treat the washed slurry with CO.sub.2 bubbling and discharge the treated slurry to the next stage, multistage separators configured to separate solid particles from treated slurry and recycle the unreacted solids back into the pre-washing device, a by-product preparation device configured to generate calcium and magnesium based products from filtrate containing target elements, a water recirculating device configured to recycle the remaining liquor back to the system. The present invention ensures the whole system is able to continuously and consistently react at maximum capacity through continuous slurry feeding and CO.sub.2 bubbling into the reactors which also enables multistage circulating reaction.