Kinetic study and mathematical modeling of the reduction of ZnO-PbO mixtures by methane

Zinc is an important industrial metal and also can be used as an energy carrier or hydrogen generator. The imperial smelting process (ISP) is the most economic method for zinc production via high-temperature reduction of ZnO-PbO concentrates with coke. The ISP method works with the high circulation rate of lead splash condensers for zinc vapor recovery. In this work, reduction of ZnO-PbO mixtures by methane at the moderate temperatures has been proposed as a new method for zinc production. The liquid zinc recoveries of this method were determined up to 88%, and therefore the lead splash condensers can be eliminated. Thermogravimetry was used for the estimation of the kinetic parameters of the reduction reactions. A mathematical model was also developed for the prediction of reduction behavior, which compared well with experimental data.