Use of carbonates in metal ion extraction

A process for extracting metal ions from aqueous solutions comprising contacting an aqueous solution containing metal ions with at least 5 wt. % of an organic carbonate based on the weight of the aqueous solution, the organic carbonate being selected from the group consisting of cyclic 1,2-alkane carbonates having the formula:

• ##STR5## where R is a straight or branched alkyl group of 8 to 20 carbon atoms, and open chain carbonates having the formula:
• ##STR6## where each R' is independently a straight or branched alkyl of at least 10 carbon atoms and where the total number of carbon atoms in both R' groups is between 20 to 36, in the absence of an organic solvent and in the absence of an alkali metal salt, where the metal ions are selected from the group consisting of gold, silver, platinum, mercury and mixtures thereof, and they are extracted in a proportion of at least 95%.

A process for extracting metal ions from aqueous solutions comprising contacting an aqueous solution containing metal ions with at least 5 wt. % of an organic carbonate based on the weight of the aqueous solution, the organic carbonate being selected from the group consisting of cyclic 1,2-alkane carbonates having the formula:

• ##STR7## where R is a straight or branched alkyl group of 8 to 20 carbon atoms, in the absence of an organic solvent and in the absence of an alkali metal salt, where the metal ions are selected from the group consisting of gold, silver, platinum, mercury and mixtures thereof.

A process for extracting metal ions front aqueous solutions comprising contacting an aqueous solution containing metal ions with at least 5 wt. % of an organic carbonate based on the weight of the aqueous solution, the organic carbonate being selected from the group consisting of open chain carbonates having the formula:

• ##STR8## where each R' is independently a straight or branched alkyl of at least 10 carbon atoms and where the total number of carbon atoms in both R' groups is between 20 to 36, in the absence of an organic solvent and in the absence of an alkali metal salt where the metal ions are selected from the group consisting of gold, silver, platinum, mercury and mixtures thereof.