Method for recovering metals from solutions
AssigneeGreat Western Chemical Company
InventorDaniel G. Bolser
Life of this patent
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Abstract
A method for recovering metals from solutions is described. A particular embodiment of the method concerns recovering copper metal. The method comprises first treating a solution containing copper ions with a sufficient amount of an inorganic acid to obtain a solution pH of from about 1.5 to less than about 2.5. A reducing metal, such as iron, is then added to the solution to precipitate metal ions, such as copper ions, as metals. The reducing metal has a mesh size preferably smaller than about 350, and even more preferably at least as small as about 400 mesh. The metal precipitate is recovered from solution.
Claims19
A batch method for recovering copper metal from an aqueous solution containing copper ions, comprising:
- adding to the solution a sufficient amount of an acid to obtain a solution pH of less than about 2.5;
- adding iron metal to the solution in an amount sufficient to reduce the copper ions in solution, the reducing metal having an oxidation potential greater than copper, the iron metal having a mesh size of at least as small as about 400;
- and
- adjusting the pH of the solution to greater than about 5 by the addition of sufficient amounts of a base.
A batch method for recovering copper metal from an aqueous solution containing copper ions, comprising:
- treating the solution with a sufficient amount of an inorganic acid to obtain a pH of less than about 2.5;
- adding to the solution a sufficient amount of iron metal to reduce the copper ions in solution, thereby forming precipitated copper metal, the iron metal having a mesh size of at least as small as about 400 mesh;
- and
- recovering the precipitated copper metal from the solution, the solution thereafter having a copper ion concentration of less than about 5 ppm.
A method for recovering copper metal from an aqueous solution containing copper ions, comprising:
- adding to the solution a sufficient amount of sulfuric acid to obtain a solution pH of from about 1.0 to about 2.0;
- adding a sufficient amount of iron powder to the solution to precipitate the copper ions as copper metal, the iron powder having a mesh size of at least as small as about 400;
- recovering the precipitated copper metal from the solution, the solution thereafter having a copper ion concentration of less than about 5 parts per million, the recovered copper metal having a purity of greater than about 70 percent.
A batch method for recovering copper metal from a circuit-board etching solution containing copper ions, comprising:
- diluting the solution with at least about a two-fold volume excess of water;
- treating the solution with a sufficient amount of sulfuric acid to obtain a solution pH of from about 1.5 to about 2.5;
- adding a sufficient amount of an iron powder to the solution to precipitate the copper ions in solution as copper metal, the iron powder having a mesh size of about 400 mesh;
- and
- recovering the precipitated copper metal, the solution thereafter having a copper ion concentration of less than about 3 parts per million, the recovered copper metal having a purity of greater than about 50 percent.
A batch method for recovering copper metal from a solution containing copper ions, comprising:
- diluting a copper ion containing solution with water;
- treating the solution with a sufficient amount of an acid to obtain a solution pH of less than about 2.5;
- adding an iron powder to the solution to precipitate the copper ions in solution as copper metal while continuously monitoring the potential of the solution, the iron powder having a mesh size of at least as small as about 400 mesh;
- increasing the pH of the solution to greater than about 5 by the addition of magnesium hydroxide after precipitating the copper metal;
- recovering the precipitated copper metal;
- and
- discharging the solution into public waste waters.
Dependencies are inferred from the claim text.