ZINC AND IRON RECOVERY FROM EAF DUST BY HYDROGEN PLASMA

摘要

Electric arc furnace (EAF) dust is a by-product from steelmaking. It contains recoverable metals such as zinc and iron, but also hazardous metals like lead, cadmium and chromium. In 1997, 3 million tonnes of EAF dust were generated worldwide and this is expected to rise to about 3.7 million tonnes in 2007. It is essential that environmentally acceptable processes be developed to treat this waste. One possible process involves reacting the zinc oxide and ferrite in the dust with hydrogen and hydrogen plasma. The reaction avoids the emission of greenhouse gases as byproducts, which is characteristic of pyrometallurgical carbon reduction processes. A hydrogen plasma includes atomic hydrogen which generates faster reduction rates than molecular hydrogen alone and can produce a metal product at temperatures as low as 500-600℃. The generation of a low-temperature atmospheric pressure plasma and experiments to assess its usefulness for EAF dust treatment are discussed in this paper.