Sherritt Gordon Mines Limited

Sherritt Gordon Limited

Sherritt Inc.

698638 Alberta Ltd.

Ian M Masters

Donald R Weir

Michael E Chalkley

Barry N Doyle

Michael J Collins

Verner B Sefton

Gerald L Bolton

Manher M Makwana

Roman M Genik-Sas-Berezowsky

John Stiksma

Manfred Neven

David John Evans

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 for the recovery of zinc from zinc-containing sulphidic material which also contains iron and from zinc oxide containing material, at least one of the materials containing lead and/or silver values. The process includes leaching zinc-containing sulphidic material and zinc oxide containing material under pressurized 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 the materials of from about 40 to about 100% to produce a residue containing a major proportion of lead and/or silver values and a leach solution containing a major proportion of the zinc and iron. The residue is separated from the leach solution and treated to recover lead and/or silver values. The pH of the solution is then raised to neutralize the acid in an iron removal step to cause precipitation of at least some of the dissolved iron from the leach solution as an iron compound. The precipitated iron compound is separated from the remaining leach solution, and the remaining leach solution is treated to recover zinc.

Recovery of zinc from zinc-containing 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.

Process for separately recovering zinc and lead values from zinc and

A process for recovering zinc from zinc-containing sulphidic material which also contains iron and lead includes leaching the material under oxidizing conditions at a temperature in the range of from about 130.degree. to about 155.degree. C. in aqueous sulphuric acid solution with a stoichiometric excess of sulphuric acid relative to the zinc content of the material of from about 50 to about 100% to produce an undissolved residue containing a major proportion of the lead and a leach solution containing a major proportion of the zinc and iron. The sulphur and lead containing residue is separated from the zinc and iron containing leach solution. Elemental sulphur is physically separated from the remaining lead-containing residue, and the remaining lead-containing residue is recovered. The zinc and iron containing leach solution is treated to recover zinc by feeding the solution to another process in which zinc-containing material is treated to recover zinc and which includes an iron-precipitation step.

Recovery of zinc from zinc containing sulphidic material

A process for recovering zinc from zinc-containing sulphidic material also containing iron and from zinc oxide containing material. Zinc-containing sulphidic material is leached 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 an initial stoichiometric excess of sulphuric acid relative to the zinc content of the sulphidic material to form a leach slurry containing dissolved zinc and iron. The leach step is continued until a substantial amount of zinc has been dissolved from the sulphidic material. Zinc oxide containing material is then added to the leach slurry to raise the pH of the slurry to a value in the range of from about 4.5 to about 5.5 to precipitate dissolved iron and form an iron-containing residue and a relatively iron-free leach solution. The residue is separated from the leach solution, and the leach solution is treated to recover zinc.

Recovery of zinc from zinc containing sulphidic materials

A process for removing radium from a radium-containing aqueous sulphate solution also containing dissolved magnesium at a pH not greater than about 10 comprises treating the solution with a soluble barium salt to precipitate radium as barium radium sulphate. The pH of the solution is raised to at least about 11 to precipitate an insoluble magnesium compound which collects the barium radium sulphate precipitate, and substantially all of the precipitates are separated from the solution.

Removal of radium from aqueous sulphate solutions

A process for the recovery of uranium values from uranium-containing material which also contains iron, arsenic and siliceous matter, includes leaching the uranium-containing material in aqueous sulphuric acid solution under conditions to provide dissolved iron present in the resultant leach solution as predominantly ferrous iron rather than ferric iron and/or to provide a sulphuric acid concentration in the leach solution sufficiently high to substantially prevent the precipitation of arsenates. Uranium values are recovered from the leach solution by solvent extraction agent which has little affinity for arsenic.

Recovery of uranium from material containing iron, arsenic and siliceous

A process for removing arsenic from an aqueous solution containing arsenic in the form of a soluble arsenate includes adjusting the pH of the solution if necessary to at least about 10, adding a soluble barium salt to precipitate arsenic as barium arsenate, and removing the precipitated barium arsenate from the solution.

Removal of arsenic from aqueous solutions

A process for the recovery of uranium values from uranium-bearing material by sulphuric acid leaching when the material also contains siliceous matter which is at least partly soluble in sulphuric acid. The process comprises leaching the material with sulphuric acid in an aqueous slurry under oxidizing conditions at a temperature within the range of from about 65.degree. C. to about 200.degree. C. and at elevated pressure, with sulphuric acid being present in a quantity only slightly in excess of the amount required to dissolve the uranium and any other element whose dissolution is desired, to produce an insoluble residue containing siliceous matter and a leach solution containing dissolved values of uranium and any other desired element.

Hydrometallurgical process for the treatment of ores

A process for recovering zinc and manganese dioxide from material containing zinc and manganese compounds, includes leaching the material to provide an aqueous solution containing manganese and zinc ions, electrolyzing the solution in one electrolytic cell with conditions inhibiting the formation of manganese dioxide and favoring the deposition of zinc, and electrolyzing the solution in another electrolytic cell with conditions favoring the formation of manganese dioxide. Zinc is removed from the one electrolytic cell and manganese dioxide is removed from the other electrolytic cell.

Process for the recovery of zinc

A method is disclosed for leaching finely divided lead sulphide bearing material to convert contained lead values to soluble lead acetate with concurrent conversion of sulphur values associated with the lead sulphide to an elemental state. The method involves forming a slurry consisting of the material dispersed in an aqueous medium containing free acetate ions and having a pH below 5.1. The slurry is reacted at a temperature of 60.degree. to 120.degree.C. with a free oxygen-bearing gas under a partial pressure of oxygen of 20 to 60 p.s.i. in order to convert lead sulphide to soluble lead acetate with concurrent production of insoluble elemental sulphur.

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Ian M Masters