Process for the Recovery of Non-Ferrous Metal Values from Non-Ferrous Metal Bearing Mineral Sulphides (Patent No: 635269)

Inventor: Mackiw, Vladimir N.

Location: Fort Saskatchewan

Comments: see Sherritt Gordon

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for separating and recovering non-ferrous metal values from non-ferrous metal bearing mineral sulphides which comprises the steps of adjusting the sulphur content of said mineral sulphides to within the range of from about 2 to about 10 mols of sulphur per mol of non-ferrous metal values, leaching the resultant non-ferrous metal bearing material with an aqueous sulphuric acid solution which has a pH value below about pH 2.5 at a temperature within the range of from about 300°F. to about 500°F. in the presence of a free oxygen bearing gas and under a partial pressure of oxygen above about 5 pounds per square inch; continuing the leaching step to extract non-ferrous metals from said metal bearing material and dissolve them in the leach solution; adjusting the pH value of the leach solution to within the range of from about pH 2.5 to about pH 5 by the addition of an alkaline reagent; reacting the slurry with a sulphidizing agent in amount sufficient to provide sulphide ions in excess of those required to combine with the dissolved non-ferrous metal values as metal sulphides whereby said dissolved non-ferrous metal vales are substantially completely precipitated from the solution as metal sulphides; subjecting the resulting slurry of undissolved residue, precipitated non-ferrous metal sulphides and leach solution to concentration by flotation; and separating and separately recovering a concentrate of said non-ferrous metal sulphides from the flotation step.
2. The process according to claim 1 in which said mineral sulphides contain the sulphide of at least one metal selected from the group consisting of nickel, copper and cobalt.
3. A process for separating and recovering non-ferrous metal values from non-ferrous metal bearing mineral sulphides which comprises the steps of adjusting the sulphur content of the mineral sulphides to within the range of from about 2 to about 10 mols of sulphur per mol of non-ferrous metal values, leaching the resultant non-ferrous metal bearing material with an aqueous sulphuric acid solution which has a pH value below about pH 2.5 at a temperature within the range of from about 300°F. to about 500°F. in the presence of a free oxygen bearing gas and under a partial pressure of oxygen above about 5 pounds per square inch; continuing the leaching step to extract non-ferrous metals from said metal bearing material and dissolve them in the leach solution; adjusting the pH value of said solution to within the range of from about pH 2.5 to pH 5 by the addition thereto of an alkaline reagent; reacting said solution with a member selected from the group consisting of a mixture of metallic iron and elemental sulphur, a mixture of metallic iron and iron sulphide, a mixture of metallic iron and pyrrhotite, pyrrhotite, hydrogen sulphide, calcium sulphide, and potassium sulphide, which contains sulphur in excess of the stoichiometric amount required to combine with dissolved non-ferrous metal values as non-ferrous metal sulphides whereby said non-ferrous metal values are substantially completely precipitated from the solution as metal sulphides; subjecting the resulting slurry of undissolved residue, precipitated non-ferrous metal sulphides and leach solution to concentration by flotation; and separating and separately recovering a concentrate of said non-ferrous metal sulphides from the flotation step.
4. The process according to claim 3 in which said mineral sulphides contain the sulphide of at least one metal selected from the group consisting of nickel, copper and cobalt.
5. A process according to claim 3 in which the pH adjustment step and the non-ferrous metal sulphide precipitation step are conducted simultaneously at a temperature within the range of from about 100°F. to 300°F.
6. A process according to claim 3 in which the pH adjustment step and the non-ferrous metal sulphide precipitation step are conducted as separate steps at a temperature within the range of from about 100°F. to about 500°F.
7. A process for separating and recovering non-ferrous metal values from non-ferrous metal bearing mineral sulphides which comprises roasting said mineral sulphides in an oxidizing atmosphere at a temperature within the range of from about 1000°F. to about 1600°F. to reduce the sulphur content thereof to within the range of from about 2 to about 10 mols of sulphur per mol of non-ferrous metals; dispersing finely divided roasted metal bearing material in an aqueous sulphuric acid leach solution to form a slurry having a pH value below about 2.5; reacting said slurry with a free oxygen bearing gas at a temperature within the range of from about 300°F. to 500°F. and under a partial pressure of oxygen above about 5 pounds per square inch; continuing the leaching step to extract non-ferrous metals from said metal bearing material and dissolve them in the leach solution; adjusting the pH value of said solution to within the range of from about pH 2.5 to about pH 5, precipitating dissolved non-ferrous metal values from said solution as sulphides; subjecting the resulting slurry of undissolved residue, precipitated non-ferrous metal sulphides and leach solution to concentration by flotation; and separating and separately recovering a concentrate of said non-ferrous metal sulphides from the flotation step.