Optimal Operational Conditions during Production of Lead-Calcium-Tin Anodes for Improve Their Mechanical Properties

Previous works have shown that a minimum yield strength s0 of 58 MPa for leadcalcium- tin anodes of 6 mm thickness and a nominal composition of 0.7% Ca and 1.3% Sn are required to avoid early deformations and distortions during their operation in copper electrowinning cell. This s0 value for the anodes is associated with a terminal cold rolling process and a further precipitation hardening prior to their installation in the electrowinning cells. The objectives of the present work are to determine the alloy recrystallization temperature according to Ca and Sn contents, the maximum cold rolling temperature and the aging time required to obtain the desired mechanical quality. The results indicate that recrystallization temperature ranges between 120 and 150°C, according to the anode composition. To reach the desired deformation and precipitation hardening and consequently a yield strength of 58 MPa, the maximum cold rolling temperature is 45°C and the minimum aging time, 30 days.