摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A process for removing mercury or other metal impurities from elemental sulphur contaminated therewith includes mixing such elemental sulphur in a molten state with an aqueous sulphide solution or an aqueous solution of sufficiently high pH which reacts with elemental sulphur and forms a sulphide solution to cause extraction of mercury or other metal contaminants from the elemental sulphur into the aqueous sulphide solutions, and separating the aqueous sulphide solution containing mercury or other metal contaminants from the molten elemental sulphur to provide an elemental sulphur product substantially free from mercury and other metal contaminants.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.