| 摘要 |
The invention relates to a process for smelting refined lead and lead alloys using alkaline refining, in superior economic and environment-protection conditions as compared with the current ones. According to the invention, the process comprises the following stages: a. zinc removal performed at temperatures in the range of 380...400°C by introducing NaOH on the surface of the metal bath in the refining kettle, with the stirrer stopped, the stirrer being then started after NaOH melting, afterwards the ash formed at the surface of the metal bath being removed and the operation being repeated until bringing the Zn under the admissible limit; b. copper removal performed by introducing a mixture of sulphur and pyrite into the metal bath brought to a temperature of 330...340°C, as follows: if Cu<0.06%, the mixture will contain 30% pyrite and 70% sulphur; if Cu=0.06...0.1%, the mixture will contain 35% pyrite and 65% sulphur; if Cu>0.1%, the mixture will contain 40% pyrite and 60% sulphur, the essential and compulsory condition for optimal copper removal being the presence in the bath of a Sn content which is twice the Cu content, at a temperature ranging at the lower limit of the range 330...340°C, c. removal of As, Sn and Sb performed at a temperature in the range of 550...620°C, where the reagent used is NaNOand a mixture of NaOH and NaNOin a ratio of 1:3, as follows: for As removal, the temperature of the metal bath is brought to 580°C and only NaNOis introduced therein; for Sn removal, a mixture of NaOH and NaNOin a ratio of 1:3 is used, at a temperature in the range of 600...620°C; for Sb removal, the temperature of the metal bath is lowered to the lower limit of the range 550...580°C, using as a reagent either a mixture of NaOH and NaNOin a ratio of 1:3, or only NaNO, the essential condition for this operation being that Sn cannot be removed before As is removed and Sb cannot be removed before Sn is removed. |
