| 摘要 |
1,251,290. Electro-refining of lead. ITT INDUSTRIES Inc. July 23, 1969 [Aug.1, 1968], No.36992/69. Heading C7B. Lead is electro-deposited using an aqueous solution containing Pb Si F 6 (e.g. 4-10% Pb content), H 2 Si F 6 (e.g. 5-12%) and, as additive for producing a dense, smooth, uniform cathode deposit, 140- 1200 mg/l of a lignosulphonate (e.g. spent sulphite liquour from wood pulping) and 40-600 mg/l of a water-soluble block copolymer of polyethenoxy polypropylene oxides with at least 13 polypropylene oxide units and 20-90% ethenoxy content. |
