Abstract
Two adjustable parameters, namely the oxygen efficiency and the “imperfect combustion ratio” of the furnace charge, were introduced into an equilibrium calculation program developed by Goto. In order to calculate the weights of matte and slag more accurately, all the other elements which are not incorporated in Goto's program were treated as one component. The overall pyrometallurgical reaction in a copper flash smelting furnace was analyzed by the modified program.
The results obtained are summarized as follows:
(1) The important elemental compositions calculated for matte, slag and gas phases were in good agreement with the values of chemical analyses by setting the oxygen efficiency so that the experimental and calculated matte grades are equal.
(2) In the case of the magnetite content of the slag, however, the analyzed values were much larger than the calculated ones. The re-evaluation of the activity coefficient of magnetite in slag brought a relatively good agreement although the analyzed values were still larger by about 3% than the calulated ones.
(3) The measured oxygen pressures were 2 times as high as the calculated ones, and this result shows the same trend as the magnetite content of the slag. These results may imply that the magnetite and hematite which are contained in the furnace charge and/or formed in the upper zone of the reaction shaft are absorbed by the slag to a greater extent than the equilibrium content.
(4) If the performance of the concentrate-burner is not adequate, the calculated temperature will be higher than the measured one. This temperature difference was explained to some extent by evaluating the “imperfect combustion ratio” of the furnace charge.
