In-situ efficient removal of copper and minimization of lead loss in crude lead refining process via supergravity separation

Efficient separation of copper and lead is a difficult part in crude lead refining process, in which the copper dross generally contains significant amounts of lead due to the limitations of current slagging extractor equipment. Therefore, a new method was proposed for in-situ efficient removal of copper and minimization of lead loss in crude lead refining process via supergravity separation. The crystallization behavior of copper indicated that for crude lead with a copper content of 2 wt%, copper particles precipitated significantly at 600–330 ℃ and the precipitation rate reached 96.2 % at 330 ℃. Thus, copper removal from crude lead could be carried out via supergravity separation at 330 ℃ and the results indicated that 99.9 % of copper particles were removed and the copper content in the lead liquid could be lowered to 0.0773 wt%, which could be directly transferred to the electrolytic refining process. Meanwhile, the lead content in copper particles was reduced to 21.7 wt%, which was far superior to existing processes. For further reducing the lead loss in the copper removal process, the separation behavior of copper was investigated which suggested that the lead content in copper particles dropped from 21.7 wt% to 1.4 wt% as the temperature increased from 330 to 600 ℃. Hence, a two-step separation was used to further reduce the lead content in the copper particles to 4.5 wt% by supergravity separation at 500 ℃ and 330 ℃, respectively. Finally, a new process route was proposed for efficient in-situ removal copper from crude lead.