Reaction Mechanism in Copper-making Stage of PS Copper Converter

摘要

Oxygen probes were applied to a PS converter in copper-making operation, and the oxygen pressures of white metal and blister copper in the converter were measured through the converter's mouth and through a tuyere, respectively. Based on the obtained results, the following reaction mechanism has been deduced. The copper-making stage of a PS converter may be classified into three stages, i.e. the early substage where the tuyeres are completely in white metal, the intermediate substage where both phases of white metal and blister copper coexist in the converter and the tuyeres are in the blister copper, and the final substage where the white metal has disappeared from the converter. In the early stage, direct oxidation of white metal by oxygen gas contained in the reaction air progresses in the vicinity of the tuyeres. Cu_2S(l)+O_2(g) =2Cu(l)+SO_2(g)………..(1) In the intermediate substage, the following three reactions proceed near the tuyeres, at the interface of blister copper and white metal phases, and in the bulk of the blister copper, respectively.O_2(g)=2O(l)……………………(2)Cu_2S(l)-2Cu(l)+S(l)……………(3)S(l)+2O(l)=SO_2(g)……………(4)Here the most important factor is that reaction(4) progresses under the condition of P_(SO_2)=1 atm. It is not dependent on how high the SO_2 pressure of the waste gas from the converter is. Because the condense phases, i.e. the white metal and blister copper phases, are not in equilibrium with the gas phase. In the final substage, reactions(2) and (4) only proceed because the white metal is no longer in the converter. Some of the blister copper can be excessively oxidized to the extent that Cu_2O(s) is formed according to equation(s). However the final degree of oxidation of the whole blister copper does not reach this level.2Cu(l)+1/2O_2(g)=Cu_2O(S)…………………(5)