The invention relates to a flotation agent of formula (I):

##STR00001## where A is chosen from: (II), (III), or (IV):

##STR00002## in which: the group R represents a hydrogen atom or a linear or branched, saturated or unsaturated, C.sub.1-C.sub.4 alkyl radical; the group R, which is identical or different from the group R, represents a hydrogen atom or a linear or branched, saturated or unsaturated, C.sub.1-C.sub.4 alkyl radical; the group R, which is identical or different from the groups R and R, represents a hydrogen atom or a linear or branched, saturated or unsaturated, C.sub.1-C.sub.4 alkyl radical; n is an integer between 1 and 6; m is an integer between 1 and 20; Y.sub.1 and Y.sub.2, are chosen independently from X.sub.1 or a radical C(S)SX.sub.2, wherein X.sub.1 is a hydrogen atom, an alkali metal or an alkaline-earth metal, and X.sub.2 is an alkali metal or an alkaline-earth metal.

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective removal of carbonate-forming alkaline earth elements from slag. The resulting processed slag has a reduced tendency to form carbonate salts on environmental exposure, and reduced tendency to fracture due to the formation of such salts. The lixiviant used can be regenerated and recycled for use in subsequent iterations of the process.

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective removal of carbonate-forming alkaline earth elements from slag. The resulting processed slag has a reduced tendency to form carbonate salts on environmental exposure, and reduced tendency to fracture due to the formation of such salts. The lixiviant used can be regenerated and recycled for use in subsequent iterations of the process.

A method for recovering scandium is provided, which is capable of recovering highly-pure scandium from nickel oxide ore in a simple and efficient manner. The method for recovering scandium according to the present invention includes a scandium elution step S2 of passing a solution containing scandium through an ion exchange resin to obtain an eluted liquid containing scandium from the ion exchange resin, a neutralization step S3 of adding for neutralization a neutralizing agent to the eluted liquid, a solvent extraction step S4 of solvent-extracting the neutralized eluted liquid using an amine-based extracting agent, and a scandium recovering step S5 of obtaining a scandium precipitate from residual liquid separated by the solvent extraction, and then roasting the precipitate to obtain scandium oxide.

Provided is a method for recovering scandium, with which it is possible to easily and efficiently recover high-purity scandium from nickel oxide ores. This method for recovering scandium involves passing a solution containing scandium through an ion exchange resin, then subjecting the eluant eluted from the ion exchange resin to solvent extraction and separating the extraction residual liquid and the extraction agent after extraction, then performing an oxalation process on the extraction residual liquid to obtain a scandium oxalate precipitate, and roasting the precipitate to obtain scandium oxide, wherein the method is characterized in that an amine-based extraction agent is used as the extraction agent for solvent extraction.

Provided is a method for recovering scandium, with which it is possible to easily and efficiently recover high-purity scandium from nickel oxide ores. This method for recovering scandium involves passing a solution containing scandium through an ion exchange resin, then subjecting the eluant eluted from the ion exchange resin to solvent extraction and separating the extraction residual liquid and the extraction agent after extraction, then performing an oxalation process on the extraction residual liquid to obtain a scandium oxalate precipitate, and roasting the precipitate to obtain scandium oxide, wherein the method is characterized in that an amine-based extraction agent is used as the extraction agent for solvent extraction.

The present applications relates to methods for the simultaneous leaching and extraction of precious metals. For example, the present application relates to methods of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium such as a gold- and/or palladium-containing ore in one step using a compound of Formula I:(I).

##STR00001##

The present invention relates to a process for efficiently enriching and recovering noble metals of platinum and palladium based on solvent extraction, wherein isoamyl alcohol is used as extracting agent and 2-methoxyphenyl thiourea is used as extraction-assisted complexing agent. 2-methoxy-phenyl thiourea is added to aqueous phase to react with platinum and palladium, and isoamyl alcohol is used as extracting agent to extract the organic phase, thus realizing the purpose of separating and extracting noble metals from base metals while enriching noble metals of platinum and palladium. The present invention, which can not only realize the separation of noble metals and base metals, but also enhance the enrichment and recovery ratios of noble metals of platinum and palladium, with low cost reagents, small influence on the environment and simple technical process, thus is a new and efficient extraction and enrichment system for noble metals.

The present application relates to methods for leaching and extraction of precious metals. For example, the present application relates to methods of leaching gold, palladium and/or platinum from a substance comprising gold, palladium and/or platinum (such as a gold-containing ore or a platinum group metal (PGM) concentrate) using an organic solvent that is water-miscible or partially water-miscible.

A method of separating a metal from a solution comprises adding to the solution a compound having a structure represented by Formula (I): wherein: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently a substituted or unsubstituted aryl group or a substituted or unsubstituted C1-C8 hydrocarbyl group: and Z is a C2-C6 hydrocarbyl group or an aryl group.