| 摘要 |
A method for ion exchange removal of lead ion from solution utilizes a material which is insoluble in the solution and contains ion-exchangeable strontium or calcium or both. Ion exchange removal of even very low concentrations of lead has been found to be selective in the presence of gold and gold-alloying metals such as cobalt, nickel, iron, antimony and indium. The use of strontium or calcium exchange materials is found to be effective to remove lead ion from a liquid in the presence of gold and, e.g., cobalt ion, without significant removal of gold or cobalt. Apparatus in accordance with the invention includes a liquid-permeable contact material comprising an exchange material which may be distended upon a liquid-permeable support for passage therethrough of liquid to be treated. A gold-plating solution in accordance with the invention comprises a source of gold and contains calcium and/or strontium ion and not more than about 20 ppm lead. |
