Optimization of the composition and manufacturing technology of cathode drums used in electrolytic copper production

The aim of this work is selection of the optimal composition of the working surface of cylinder cathodes and the development of rational methods of their manufacture. From literature sources and on the basis of extensive electrochemical studies (determination of corrosion resistance by the potentiostatic method, galvanostatic definition of copper crystallization surge, as well as modeling of the process of obtaining the foil), it was found that the alloy composition 15 Cr - 65 Ni - 20 Mo has the best performance among the investigated alloys. In specific conditions of cylinder cathodes operation, lack of materials for the alloy, the need to obtain the blank of a larger diameter with a homogeneous fine-grained and dense surface, electroslag smelting (ESS) was used as the basic technology. Application of welding technology has made it necessary to take into account two additional factors: the potential damage of the surface by intergranular corrosion (IGC) and the tendency of austenitic alloys to hot cracking. To prevent IGC niobium was added to the alloy in traditionally sufficient quantities (1%). Additional introduction of niobium into the alloy can reduce the technological strength. Without taking into account the mutual influence of Nb Cr and Mo, the 15 Cr - 65 Ni - 20 Mo composition was chosen. Comparative pilot scale tests of cylinder cathodes, carried out at the experimental site of Kyshtym Copper Electrolyte Plant, showed efficiency of the proposed material at high temperatures compared to conventional ones, thus significantly improving the productive capacity of the electrode position process. It was found that non-consumable electrode argon arc welding can be carried out in a wide range of conditions without using any technological methods in absence of cracking which would enable to produce the actual shell from less scarce materials.