| 摘要 |
The parent patent described the leaching of a sulphide ore or concentrate, contg. Pb and other metals, with an aq. soln. contg. the chloride(s) of Cu, Bi and/or Ag, using below the stoichiometric amt. of chloride needed for complete soln. of the Pb. - In this addn. the Pb in soln. is recovered as PbCl2 crystals, which are then melted and reduced by H2. Redn. is pref. at 750-850 degrees C., esp. using H2 diluted by an inert gas and injected into the molten PbCl2. The hourly flow of H2 is pref. at least twice the stoichiometric amt. necessary for total redn. of the PbCl2; and the H2 in the gases leaving the redn. process is pref. sepd. from the HCl obtd. and recycled to the redn. process, whereas the HCl is recycled for dissolving the lead. - Metallic lead with high purity can be obtd.; the Cl ions are directly recovered as HCl which is recycled; and the reducing agent is inexpensive. The process also eliminates extra processing stages which were necessary with the earlier patents. |
