Abstract: The ore is subjected to nitric acid leaching and the leach solution is heated to a temperature at which one of the additional sulfur and iron values is selectively insolubilized with respect to the solution, while the other is maintained in solution for subsequent separation from the liquor after the insolubles have been removed and the liquor has been neutralized. In addition, in one embodiment of the invention the heating and acid neutralization steps are controlled within certain prescribed limits to make it possible to remove the metals from the liquor by solvent extraction without the problem of lasting precipitates forming in the liquor and fouling the extraction process. Where there is a sizable amount of dissolved iron in the liquor, the liquor may be subjected to autoclaving at a temperature above about 149.degree. C (300.degree. F) to precipitate the iron as the oxide thereof. This effect is possible even where the liquor is high in sulfate concentration.

Abstract: The ore is subjected to nitric acid leaching and the leach solution is heated to a temperature at which one of the additional sulfur and iron values is selectively insolubilized with respect to the solution, while the other is maintained in solution for subsequent separation from the liquor after the insolubles have been removed and the liquor has been neutralized. In addition, in one embodiment of the invention the heating and acid neutralization steps are controlled within certain prescribed limits to make it possible to remove the metals from the liquor by solvent extraction without the problem of lasting precipitates forming in the liquor and fouling the extraction process. Where there is a sizable amount of dissolved iron in the liquor, the liquor may be subjected to autoclaving at a temperature above about 149.degree.C (300.degree.F) to precipitate the iron as the oxide thereof. This effect is possible even where the liquor is high in sulfate concentration.

Abstract: The ore is subjected to nitric acid leaching and the leach solution is heated to a temperature at which one of the additional sulfur and iron values is selectively insolubilized with respect to the solution, while the other is maintained in solution for subsequent separation from the liquor after the insolubles have been removed and the liquor has been neutralized. In addition, in one embodiment of the invention the heating and acid neutralization steps are controlled within certain prescribed limits to make it possible to remove the metals from the liquor by solvent extraction without the problem of lasting precipitates forming in the liquor and fouling the extraction process. Where there is a sizable amount of dissolved iron in the liquor, the liquor may be subjected to autoclaving at a temperature above about 149.degree.C (300.degree.F) to precipitate the iron as the oxide thereof. This effect is possible even where the liquor is high in sulfate concentration.