Investigation of heavy metal flows in a copper pyrometallurgical process of a typical smelter

Abstract

The non-ferrous smelting industry is a major polluter of heavy metals, and investigations on the flow of heavy metals in the metallurgical process are important references and the basis for optimization of the smelting process and control of heavy metal pollution. In this work, using a typical copper smelter as the research object, we examined and analyzed the content and status of the heavy metals lead, arsenic, cadmium, mercury, and chromium in the slag, ash, solid waste, and products of the copper pyrometallurgical process and explored the flow and enrichment of heavy metals in each stage of smelting, converting, and refining. The results showed that lead and arsenic were the most abundant heavy metals in copper concentrate, of which about 66.21% of lead and about 65.02% of arsenic escaped with the flue gas during the pyrometallurgical process and were trapped in the white ash. During the entire copper purification process, about 75.17% of heavy metals were removed in the smelting process, about 21.88% in the converting process, and about 2.92% in the refining process. The final heavy metals discharged into the atmosphere were only lead, arsenic, and mercury, accounting for about 0.03% of the total heavy metal content. It is worth noting that 50% of the mercury in the raw material was discharged into the atmosphere. Since mercury is persistent, easily transportable, highly bio-concentrated, and toxic, mercury pollution requires increased attention.