Effect of Additives in the Electrorefinery Start-Up of PT. Freeport Indonesia

Starting up one of the world’s biggest copper refineries, PT. Freeport Indonesia was using a typical electrolyte containing [Cu] of 50 gpl, Free Acid of 170 gpl, [As] of 3 gpl and [Cl] of 0.05 gpl. While anodes quality has a range of Cu and O₂ of 99.4–99.7% and 500–600 ppm, respectively. Due to the limited number of anodes, the only option was to start one group out of 16 groups, using only 10% of the design capacity. This gap affected the performance of equipment, such as pumps and heaters. Another limiting factor was unavailability of the solution purification section at that stage. To mitigate soluble impurities and copper from the anodes, circulating five additional cell groups was conducted. This provides challenges in additives dosing, and some iterations of additives dosing was conducted during the start-up. Despite the unusual set-up and typical start-up challenges, such as unwanted stops, the copper refinery start-up was successful, producing LME grade A from the first cathode. Result of 2nd cycle shows significant improvement in quality improved production by minimizing dendrite growth and increasing current efficiency and further, the result of the 3rd cycle is shown to produce best cathode among these three cycles.