| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method where, from a lead-containing material such as lead carbonate, lead oxide, lead hydroxide and lead sulfate generated from a metal refining or industrial waste treatment stage, high purity metal lead is efficiently recovered. <P>SOLUTION: A lead-containing material is leached with a nitric acid solution under the conditions satisfying a pH of 1 to 3 and a reaction time of≥1 hr, is filtered, is thereafter subjected to substitution reaction in the range of a pH 2 to 3 using metal lead for the purpose of removing metal impurities nobler than the lead in the filtrate. From the lead nitrate solution, lead dioxide is precipitated on an anode and metal lead is precipitated on a cathode by an electrowinning process. Thereafter, the lead dioxide is peeled and recovered, and is subjected to melt reduction together with a reducing agent, so as to be metal lead. Subsequently, the metal lead is subjected to furnace cooling, and, caustic soda is added thereto, so as to remove trace impurities. Then, casting is performed, so as to obtain electrolytic lead, and electrodeposited lead recovered from the cathode is further melted. Similarly, the trace impurities are removed away, and casting is performed, so as to obtain electrolytic lead. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
