One-step separation of hazardous element lead in brass alloy by physical external field

Abstract The use of lead brass is increasingly restricted because of the harmful effects of lead on human function and the natural environment. However, how to separate the large amount of lead in existing brass scrap in green, energy-saving and efficient manner is a serious problem. In this study, the effect of pulsed electric current on the lead distribution of impurity elements in molten copper was investigated. The morphology and distribution of lead in the samples treated with or without pulse current were characterized and analyzed by scanning electron microscopy and electron probe micro-analyzer. The impurity lead in the pulsed sample is concentrated near the anode compared to the sample that is not pulsed. After the pulse treatment, the lead content in the middle of the sample is greatly reduced compared with the lead content in the original sample, and the separation efficiency reaches about 86.7%. The reason for the pulse current separation of impurity element lead in brass is that the current has a large electromigration force to the lead atom due to the effective charge disparity between the impurity lead and the matrix, so the lead moves in a direction under the action of current, thereby achieving the effect of impurity lead separation. It only needs one step to separate lead from brass by pulse current, and the separation efficiency is relatively high. Therefore, as a physical external field that is easy to regulate, pulse current has great the potential to develop into a novel method for energy-saving and efficient separation of impurity elements in the melt.