| 摘要 |
<p>PURPOSE:To easily and efficiently obtain the title high-purity zinc white with less energy to be used by mixing a specified dead-roasted material with coke as the reducing agent, heating the mixture to obtain metallic zinc vapor, and reoxidizing the vapor in a furnace. CONSTITUTION:The steel making flue dust is charged in a first-stage rotary heating kiln 3 without adding an additive to the dust and dead-roasted at 800-1,100 deg.C for about 1hr to selectively volatilize Pb, Cd, and Cl, and the obtained volatiles are recovered in a first-stage recovery device 5. Meanwhile, the nonvolatile Zn and Fe components are left as ZnO and Fe2O3, and the obtained dead-roasted material (A) is collected from an outlet 3b. About 30wt% coke as the reducing agent is then added to the A component, the mixture is charged into a second-stage heating kiln 6 and heated at 900-1,100 deg.C for about 1hr, hence the ZnO in the A component is transiently reduced, and the formed metal Zn vapor (B) is volatilized. The B component is reoxidized by heated air and sent into a second-stage recovery device 8 through a duct 7, and zinc white is obtained from the steel making flue dust.</p> |
