Patent ID: 7384533

Claim:
An electrowinning process utilizing an electrolytic cell having at least one gas-evolving insoluble anode, at least one cathode, and an electrolyte solution in contact with said anode and cathode and comprising an acid, a metal ion source and a solvent, said process comprising applying an electrical potential between said anode and said cathode to induce current flow wherein said electrolyte solution contains at least one organic additive in an amount sufficient to reduce cell operating potential at constant current, compared to the same process without such organic additive, said organic additive being selected from the group consisting of: quinhydrone; 1,4-dihydroxybenzene-5-sulfonic acid, potassium salt; 3,5-dimethoxyphenol; 1,3-dihydroxynaphthalene; phloroglucinol dihydrate; tetrahydroxy-1,4-quinone hydrate; 4,6-dihydroxypyrimidine; 2,4,5-trihydroxypyrimidine; 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid, sodium salt monohydrate; 3,6-dihydroxypyridazine; 1,3-dihydroxybenzene; 4-hydroxypyridine; 2,4-dihydroxypyrimidine; 2,4-dihydroxypyridine; N-hydroxysuccinimide; 2-hydroxypyridine; 4-hydroxypyrimidine; 4,6-dihydroxy-2-methylpyrimidine; 2-hydroxypyrimidine hydrochloride; 3-hydroxypyridine; 1,3-dihydroxy-5-methoxybenzene; 1,2,4-trihydroxybenzene; 1,2,3-trihydroxybenzene; 1,2-dihydroxybenzene; 4,6-diaminopyrimidine; 1,4-diazabicyclo[2,2,2]octane; 2-amino-2-thiazoline; methyl sulfoxide; L-histidine; and mixtures thereof.