A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt.

Provided is a method for inhibiting extractant degradation comprising preparing step, extracting step and scrubbing step, the method including: (a) the preparing step of a DSX solvent by adjusting the extractant concentration of the DSX solvent to a specific range; (b) the extracting step of metal included in the feed solution by adjusting the ratio of the organic (solvent) and an aqueous (solution) as a feed solution; (c) the scrubbing step of adjusting the zinc concentration of the solution using zinc sulfate; and (d) stripping step.

Provided is a method for inhibiting extractant degradation comprising preparing step, extracting step and scrubbing step, the method including: (a) the preparing step of a DSX solvent by adjusting the extractant concentration of the DSX solvent to a specific range; (b) the extracting step of metal included in the feed solution by adjusting the ratio of the organic (solvent) and an aqueous (solution) as a feed solution; (c) the scrubbing step of adjusting the zinc concentration of the solution using zinc sulfate; and (d) stripping step.

A process is described for recovering a non-ferrous metal from a first solid residue comprising iron. In this process, the first solid residue is mixed with a second solid residue including sulphur, thereby obtaining a particulate mixture. The particulate mixture is subjected to a roasting step at a temperature of at least 650° C. to obtain a roasted mixture, and the roasted mixture is subjected to leaching in a liquid at a pH of at least 5.5 to obtain a solution enriched with the non-ferrous metal.

Provided is a method for inhibiting extractant degradation in the DSX process through the manganese extraction control, the method comprising: (a) stirring DSX solvent and DSX feed solution, which is a solution containing a valuable metal from which iron has been removed in an agitator, in which soda ash (Na.sub.2CO.sub.3) is further added to maintain a constant pH; and (b) scrubbing the manganese from the DSX solvent, extracted in step (a).

Provided is a method for inhibiting extractant degradation in the DSX process through the manganese extraction control, the method comprising: (a) stirring DSX solvent and DSX feed solution, which is a solution containing a valuable metal from which iron has been removed in an agitator, in which soda ash (Na.sub.2CO.sub.3) is further added to maintain a constant pH; and (b) scrubbing the manganese from the DSX solvent, extracted in step (a).

Provided is a method for inhibiting extractant degradation comprising preparing step, extracting step and scrubbing step, the method including: (a) the preparing step of a DSX solvent by adjusting the extractant concentration of the DSX solvent to a specific range; (b) the extracting step of metal included in the feed solution by adjusting the ratio of the organic (solvent) and an aqueous (solution) as a feed solution; (c) the scrubbing step of adjusting the zinc concentration of the solution using zinc sulfate; and (d) stripping step.

Provided is a method for inhibiting extractant degradation comprising preparing step, extracting step and scrubbing step, the method including: (a) the preparing step of a DSX solvent by adjusting the extractant concentration of the DSX solvent to a specific range; (b) the extracting step of metal included in the feed solution by adjusting the ratio of the organic (solvent) and an aqueous (solution) as a feed solution; (c) the scrubbing step of adjusting the zinc concentration of the solution using zinc sulfate; and (d) stripping step.

Provided is a method for inhibiting extractant degradation in the DSX process through the metal extraction control, the method comprising steps of: (a) adding limestone to a copper solvent extraction-raffinate to precipitate iron (Fe) and aluminum (Al) as a slurry, recovering a clarifying liquid; and (b) adding sulfuric acid to the recovered clarifying liquid to adjust the pH thereof.

Provided is a method for inhibiting extractant degradation in the DSX process through the metal extraction control, the method comprising steps of: (a) adding limestone to a copper solvent extraction-raffinate to precipitate iron (Fe) and aluminum (Al) as a slurry, recovering a clarifying liquid; and (b) adding sulfuric acid to the recovered clarifying liquid to adjust the pH thereof.