| 摘要 |
<p>Crude pyritic sulphide ores are exposed to the atmosphere in heaps or vats and treated with water without applying heat, whereby free sulphuric acid is generated, copper is removed as sulphate and the lead converted to sulphate. The ore is then treated with a strong solution of brine or other chloride to extract lead, silver and gold, which are then precipitated together by iron or zinc, or the silver and gold may be first precipitated by lead and the lead be then precipitated by iron or zinc. The residual brine, after treatment, if necessary, with limestone or magnesia to neutralize free hydrochloric acid, may be re-used in the process.</p> |
