Removal of chloride from EAF-dust by reactive roasting at low temperature

In Taiwan, nearly 170,000 tons of filter dust from electric arc furnace steel plant (EAFD) is yielded yearly. The most widely used technology for the recovery of zinc oxide from EAF dust is Waelz Process. In comparison with the other countries, the high chloride content in EAF dust in Taiwan, however, leads to the low price of crude zinc oxide, the secondary air pollution and also the high temperature corrosion inside treatment plant. It was reported in literature that the removal of chloride from EAF dust can be achieved by mean of high temperature sintering. Due to the high chloride content, sintering also leads to the loss of zinc through the evaporation of zinc chloride. In order to prevent the loss of zinc and increase the value of zinc oxide product, the main purpose of this research was the investigation of chloride removal by roasting at low temperature under various atmospheric conditions. The influences of reactive gases such as CO₂ and SO₂, temperature and roasting time were investigated. As conclusion, the new direction for chloride removal is suggested.