Metal Refinery

The precious metal operations consist of the smelter, the copper-leaching and electro winning plant and the precious metals refinery. The operations are designed in such a way that raw materials, can enter the flow-sheet at the most optimal process step. The smelter separates precious metals in a copper bullion, from mostly all other metals, concentrated in a lead slag, further treated at the base metals operations. After leaching out the copper in the leaching and copper electro winning plant, the precious metals are collected in a residue that is further refined at the precious metals refinery. The precious metals refinery combines different methods recover precious metals (silver (Ag) and gold (Au)) and platinum group metals (platinum (Pt), palladium (Pd), rhodium (Rh), iridium and ruthenium).

Precious metals: Ag, Au, Pt, Pd, Rh; source: Umicore 

The main processing steps of the base metals operations are the lead blast furnace, the lead refinery and the special metals plant. The lead blast furnace reduces lead slag from the smelter and transforms them into impure lead bullion, nickel speiss, copper matte (which is returned to the smelter) and depleted slag. The impure lead bullion is further treated in the lead refinery. Besides pure lead (Pb) the process generates special metals residues. These are, together with the main side-streams of the precious metals operations, further refined into pure metals and metals salts to indium (In), selenium (Se), tellurium (Te) and antimonate (Sb). After leaching the nickel out of the nickel speiss and turning it into nickel sulfate, the remaining precious metals residue is treated at the precious metals refinery. The furnace slag is mainly used in the concrete industry.

Non precious metals: Pb, In, Se, Te, Sb; source: Umicore

The recovery of precious metals out of complex recyclables and raw materials via an integrated smelter is an economic and environmental sound solution. Umicore operates almost a zero-waste process, for e-scrap less than 1% of the feed is finally going into a controlled depot, herein hazardous substances are concentrated and safely isolated. In contrast, a wet chemical leaching process focuses only on copper, gold and sometimes palladium and silver, but creates a substantial amount of hazardous waste. Also is the effectiveness of integrated smelting much higher than leaching, for gold up to four times. Additionally the plastics in the e-waste are more than sufficient to replace all fuel needed for the smelting process.