Primary smelting of other metals

As noted in the last section, lead ores often occur naturally in conjunction with the ores of other metals, and hence primary production of these metals may give rise to emissions of lead. Most important in this respect are the production of zinc and copper. 

In the electrolytic production of zinc, the roasted ore concentrate is leached with sulphuric acid and after purification of the resultant solution, zinc is recovered by electrolysis. No significant atmospheric emissions result from this process, other than those from the roasting process. 

Property Sintering Horizontal retort Vertical retort 

Production of primary copper involves an initial roasting of the ore concentrate. This is followed by smelting in a reverberatory or electric furnace, the former being more commonly used. The copper matte produced is purified in a converter, forming bhster copper which is further refined, mostly by an electrolytic process. The composition of the most contaminated effluent streams appears in Table 5.5. Fugitive emissions inevitably also accompany the production processes. 

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