- Major greenfield plant designed to process 160 000 tpa of lead concentrate
- ISASMELT™ replaced sinter plant, capturing sulphur and producing lead bullion directly
- Significant decrease in slag reduction duty of blast furnace
- ISASMELT™ furnace permits emissions capture
China Yunnan Metallurgical Group (CYMG) commissioned a lead ISASMELT™ furnace in 2005 at their greenfield zinc and lead smelting complex at Qujing, Yunnan Province, China.
The ISASMELT™ furnace has a design capacity of 160,000 tpa of lead concentrate to produce lead bullion and a high lead slag. The high lead slag is cast in a straight line casting machine and fed as solid blocks to a blast furnace for reduction. This process combines the ISASMELT™ furnace for smelting with the blast furnace for reduction. The ISASMELT™ furnace effectively replaces the sinter plant of a traditional lead smelter. The ISASMELT™ furnace has an advantage over the sinter plant in that it can convert a significant portion of the lead in feed directly to lead metal, thus decreasing the slag reduction duty of the blast furnace. In the CYMG plant over 40% of the lead in feed reports directly to lead metal in the ISASMELT™ smelting furnace.
The ISASMELT™ furnace also has the advantage that it is much smaller and simpler to maintain than a sinter plant and can be readily enclosed to eliminate emissions. The offgas from the ISASMELT™ furnace has relatively high sulfur dioxide content, suitable for conversion to acid in a conventional sulfuric acid plant. The slag product is low in sulfur compared with sinter and thus the blast furnace offgas contains a much lower concentration of sulfur dioxide than in the case of a blast furnace fed with sinter.