The production of Zn from ZnO in a two-step solar process utilizing FeO and Fe3O4

We present a model of a two-step solar process for producing Zn from ZnO. The process consists of the following reactions: image and 3FeO(s,1) + ZnO(s) → Fe3O4(s) + Zn(g). The rate and extent of decomposition of the first reaction is limited by the rate at which O2 diffuses from the liquid-gas interface. We verified experimentally that the second reaction is possible. A theoretical study shows that the Zn yield can be controlled by temperature, pressure, and partial pressure of Zn. The maximum overall efficiency of this two-step process varies from 14 to 64% in the temperature range of 2100–2200 K.