HIGH-TEMPERATURE SOLAR THERMAL-PROCESSING ZN(S) AND CO FROM ZNO(S) AND C(GR) USING TI2O3(S) AND TIO2(S)

An analytical model of a two-step solar process that produces Zn(s) and CO from ZnO(s) and C(gr) is presented. The process occurs in two steps according to the following reaction scheme: Ti2O3(s) + ZnO(s) --> Zn + 2TiO2(s) (low temperature), 2TiO2(S) + C(gr) --> Ti2O3(s) + CO (high temperature). We demonstrate theoretical effects of operating conditions on process performance. The reactions were also studied experimentally. We produced Zn(s) with the first reaction in an electric furnace in the temperature range of 900-1275 K in 1 atm of Ar. The second reaction and related ones were performed in a solar furnace. Ti2O3(s) and higher Ti(N)O2N-1(s) formed at temperatures between 1675 and 2175 K. These higher oxides also react with ZnO(s) to produce Zn(s). Some of our experiences and experimental techniques are described.