Precipitation of selenium from copper electrowinning solutions
AssigneeAmax Inc.
InventorsCvetko B. Nikolic, John M. Laferty
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Abstract
Selenium is removed from copper electrolytes by adding a substance selected from the group consisting of metals above copper in the electromotive series, excluding alkali metals, such as nickel powder, cobalt powder and iron powder. Sodium sulfide can also be used along with a subsequent addition of ferric sulfate. The amount of the reactive substance added should be sufficient to reduce the selenium content to below 2 ppm.
Claims8
A method for removing selenium from a copper-containing electrolyte solution containing over 2 ppm of total selenium which comprises,
- adding to said copper-containing solution a substance selected from the group consisting of metals above copper in the electromotive series, excluding alkali metals, in an amount at least sufficient to reduce the selenium content to below 2 ppm,
- subjecting said copper-containing electrolyte solution to an elevated temperature of at least about 190.degree. C. and a pressure of at least about 180 psig to reduce the total selenium content of said solution to less than 2 ppm by forming a selenium-containing precipitate,
- and then separating the selenium-containing precipitate from said solution.
A method of removing selenium from a copper-containing electrolyte solution containing over 2 ppm total selenium which comprises,
- adding an amount of Na.sub.2 S to said solution sufficient to reduce said selenium to less than 2 ppm,
- the amount of said Na.sub.2 S being such as not to exceed 100 ppm of sodium ions in solution,
- subjecting said solution to a temperature of at least about 190.degree. C. and a pressure of at least about 180 psig in an autoclave,
- introducing into the autoclave an amount of Fe.sub.2 (SO.sub.4).sub.3 not exceeding an amount corresponding to 5 gpl of iron per liter,
- thereby reducing said selenium to less than 2 ppm by forming a selenium-containing precipitate,
- and then separating the selenium-containing precipitate from said electrolyte solution.
Dependencies are inferred from the claim text.