Tankhouse electrorefining process produce 99.99% copper cathode and byproduct anode slime from 99.5% copper anode. Smelter supplies the Tankhouse with two types of copper anodes that are stripper and commercial, with the stripper anodes used to make starter sheet and commercial anodes responsible for cathode deposition. The copper anodes and starter sheets are loaded into commercial sections, which consist of 40 electrolytic cells per section. Voltage is applied across the anode-cathode pair to stimulate copper ions to get electrons and deposited on the cathode surface. Copper loaded cathodes are harvested periodically with desired pull weight and current efficiency. The precious metal from copper anode reports to anode slime settling down to the cell bottom, which is processed through settling tanks, press filters and dried in the oven. As the electro-refining process going, electrolyte requires regular purification and control by adding reagents and bleeding off electrolyte to remove impurities accumulated in the electrolyte, which can negatively influence the cathode quality. The Tankhouse is equipped with the following sub-systems including anode shaping and preparing units, automatic crane, starter sheet stripping & assembling, anode scrap pulling and packing unit, short-circuit monitoring system.


Nickel Plant

The Liberators in the copper Tankhouse are impurity management system in that they provide a bleed stream supplying the Nickel Plant with its feed solution through which a number of impurities of which nickel is the most important that collect in the electrolyte during the refining process.  It is important to remove the build-up of the impurities from the electrolyte solution as they may eventually contaminate the cathode if not removed. The Nickel Plant make use of a continuous carousel type ion exchange system, utilizing a uniform bead size form of the Dow XUS resin to concentrate nickel and purify it into nickel sulphate final product which is crystallized and dried to produce dry powder of nickel sulphate hexahydrate crystals. The nickel sulphate hexahydrate is then sold in 1 ton lots consisting of forty 25kg bags packed on a pallet to various customers such as steel-making industry.


Rod Casting Plant

Rod casting plant recieves refined copper cathode from the Tankhouse with content 99.99% Cu that is melted in the shaft furnace by combusting LPG under strict process monitoring. During melting, the oxygen content in molten copper is controlled by adjusting LPG and air ratio. The 11000C molten copper is then transferred through launders, holding furnace and tundish to the casting machine where copper is cast into an endless bar with temperature range of 890-9100C. Still glowing, the bar enters the rolling mills, which is made up of 12 roll stands powered by electric motors via gearboxes. Through the mills, rod diameter of 7.9mm is attained by constantly reducing the cross-section of rod from 23.5mm while lubricating rolls surface with soluble oil. The 400-5000C rod is then surface-treated and cooled by isopropyl alcohol at constant speed. The temperature is subsequently reduced to 400C. After it is dried, it is treated with protective wax coating. The rod will go through a coiler then incline conveyor for stacking and packaging.