Abstract:The end time of copper matte converting is usually determined on the basis of the status of off gas, fire, splashed matter, and detecting rods. Such determination is largely based on the operator’s subjective opinion, which could lead to under-converting or over-converting. A mathematical model can be established of the whole converting process through the METCAL system using mass balance, heat balance and elemental balance. By analyzing and calculating process parameters and controlling the quantity and timing of cold charge, the end time of slagging and copper production can be determined. The paper describes in detail the process of establishing the model and treating errors; the modified simulation model indicates that the error of determining the end of the slag-forming period can be controlled within ±5%, and that the level of Fe in Cu2S and S in blister copper both comply with the quality requirements. Real practice has shown that the model provided useful information for determining the actual ending of copper matte converting. With growing amounts of data, the prediction accuracy of the model can be further improved.