Modeling and optimization of charge materials ranges in converter furnace with enhanced passivation time in copper electrorefining process: A mixture design approach

Abstract

In this study, the design of experiments is used to study and model the time of passivation in copper electrorefining as a function of the charge of melting furnace through the preparation of copper casting anodes. As a result of optimization for the proposed optimized anodes, the charge percent values of concentrate (Co), refinery scrap (RS), and non-refinery scrap (NRS) were proposed equals to 69.1, 0.574 and 30.32 (wt.%), respectively. Experimental data confirmed the enhanced passivation time of the proposed anode was 6520 s. Also, it was observed that the molar ratio of As/(Bi+Sb) and Ag/(Se+Te) are the key factors in passivation time. Finally, the relation of passivation time (seconds) with the charge of melting furnace is proposed as: t (s)= - 3728.98 × Co + 4640.00 × RS + 3141.00 × NRS + 17763.27 × Co × RS + 25547.65 × Co × NRS - 1758.00 × RS × NRS. Moreover, adding of As ingot in casting anodes as a dose dependent of non-refinery scrap portion in the input charge of the melting unit can effectively prolong the time of passivation.