Sherritt Gordon Mines Limited

Sherritt Gordon Limited

Sherritt Inc.

698638 Alberta Ltd.

Michael E Chalkley

Ian M Masters

Michael J Collins

Donald R Weir

Barry N Doyle

Manher M Makwana

Derek E Kerfoot

John Stiksma

A process for removing mercury from elemental sulphur contaminated therewith by liquid-liquid contact by mixing of the contaminated elemental sulphur in a molten state with an aqueous solution containing sulphide and polysulphide anions for extraction of the mercury contaminant from the elemental sulphur into the aqueous sulphide solution, and separating the aqueous sulphide solution containing mercury contaminant from the molten elemental sulphur to provide an elemental sulphur product substantially free from mercury.

Purification of elemental sulphur

A process for recovering zinc and iron from zinc- and iron-containing sulphidic material, which also contains lead and silver, in which the sulphidic material is leached under oxidizing conditions in a two stage countercurrent pressure leach to produce a zinc-containing solution from which zinc can be recovered by conventional means such as electrowinning, followed by a reducing leach to produce a lead- and silver-bearing product containing substantially all of the lead and a substantial portion of the silver present in the zinc-containing sulphidic materials, and a high strength iron bearing solution having the iron in the ferrous state from which substantially pure, saleable or environmentally acceptable iron residue in the form of hematite which contains the majority of the soluble iron present in the zinc-containing sulphidic materials is produced.

Recovery of metals from sulphidic material

A process is disclosed for recovering zinc, lead, copper and precious metals from zinc plant residue, said process comprising leaching the residue with return zinc spent electrolyte, neutralizing residual acid and reducing ferric iron in the solution by addition of zinc sulphide concentrate in the presence of a limited quantity of oxygen, flotation of the resulting slurry to separate unreacted zinc sulphide, treatment of flotation tailings with sulphur dioxide and elemental sulphur to further leach iron, zinc and impurity elements and precipitate copper, flotation of the resulting slurry to separate a copper sulphide concentrate, thickening, filtering and washing of the flotation tailings followed by addition of lime and sodium sulphide to activate lead sulphate and flotation of a lead concentrate from the residue. Iron and impurity elements are precipitated from the copper flotation tailings thickener overflow solution by addition of zinc hydroxide sludge, lime and oxygen to produce a high strength, iron free zinc sulphate solution.

Recovery of metal values from zinc plant residues

A process for recovering cobalt and nickel values from cobalt and nickel containing sulphidic material also containing iron includes roasting the sulphidic material to produce a calcine containing water soluble cobalt and nickel sulphate, and leaching the calcine in aqueous sulphate solution under oxidizing conditions at an oxygen overpressure in the range of from about 50 kPa to about 1500 kPa and at a temperature in the range of from about 100.degree. to about 180.degree. C. to produce an iron-containing residue and a cobalt and nickel containing solution. The residue is separated from the solution, and cobalt and nickel values are recovered from the solution.

Recovery of cobalt and nickel from sulphidic material

A process for separately recovering zinc and lead values from zinc and lead containing sulphidic ore which also contains iron comprises subjecting ground ore to a first flotation step to float an initial lead concentrate containing zinc and produce zinc and iron containing tailings. The zinc and iron containing tailings are subjected to a second flotation step to float an initial zinc concentrate containing iron and also produce tailings. The initial zinc concentrate is subjected to a third flotation step to float a further zinc concentrate containing iron and also produce zinc and iron containing tailings. The zinc and iron containing tailings from the third flotation step and at least a lead and zinc containing portion of the initial lead concentrate are leached in a first leach step under oxidizing conditions at a temperature in the range of from about 130.degree. to about 170.degree. C. in aqueous sulphuric acid solution with a stoichiometric excess of sulphuric acid relative to the zinc content of from about 50 to about 150% so as to give a terminal acidity of from about 50 to about 80 g/L to produce a lead-containing residue and a first leach solution containing zinc and iron. The lead containing residue is separated from the first leach solution and the first leach solution is treated with the further zinc concentrate or calcine produced therefrom by roasting to dissolve zinc therefrom and precipitate a substantial amount of dissolved iron, thereby producing an iron containing residue and a second leach solution containing zinc. The iron containing residue is separated from the second leach solution, and the second leach solution is treated to recover zinc.

Growing community of inventors

St. Albert, Canada

Michael E Chalkley