According to Harris Process, tellurium, arsenic, tin and antimony can be removed from the lead bullion with molten sodium hydroxide, sodium nitrate being used as an oxidizing agent, and transferred into the alkaline salt melt. The equipment used is the so-called “Harris Cylinder”. Its performance naturally depends on the operating conditions of a given plant (assay of the lead input, pump efficiency, surfaces of the reacting phases, retention time etc.). The separation of the impurities removed through the salt melts is accomplished by a combined metallurgical and hydrometallurgical process.(Excerpt from Extractive Metallurgy of Lead and Zinc)

Generally speaking, the copper dross is treated by rotatory reverberatory furnace. In case of copper dross with high arsenic, tin and antimony, caustic soda plus iron filings are used. In reaction with caustic soda, the arsenic, tin and antimony report to sodium salt as slag to be recovered by hydrometallurgy consequently. After soda refining, the copper matte is treated by cupellation method to separate copper with lead, and lead reports into slag phase.  

Anode slime is the byproduct of copper or lead electro-refining process and found in electrolytic cell bottom or on the anode scrap surface. The copper anode slime and lead anode slime usually contain precious metals like gold and silver.

Depending on the treatment capacity, process of anode slime recovery is achieved by two different methods, i.e. pyro-metallurgy and hydrometallurgy.

Focusing on high demand of precious metal recovery and large treatment amount, Metalcess offers solution of TBRC smelting + lead distillation & gold metal extraction.

Pressure leaching can be used to pretreat anode slime for environment consideration. 

Refining dross is the result of lead refining process where impurities like copper, tellurium, arsenic-antimony-tin, silver, zinc and bismuth in sequence from lead bullion. There are many types and composition of each type of dross varies and is subjected to specific refining steps and raw material contents. Conversely, lead refining process are taken in account for the convenience of refining dross recovery. 

Metalcess provides an integrated system combining solidification and distillation technology to treat silver-zinc crust/silver foam from Parkes process, in which zinc, lead and silver are separated efficiently at the cost of low energy consumption. Noticeably, the zinc recovered from silver-zinc crust can be used as desilvering agent again for the Parkes process. While the lead alloy can be charged to lead refining pot before bismuth-removing step. This system is superior in reducing energy consumption, shortening process flow and improving working environment.

In zinc leaching, iron is removed from zinc sulphate solution by iron precipitation. The mainstay of iron precipitation includes jarosite, goethite and hematite, of which goethite is of the most economic and environmental-friendly superiority.

Goethite residue from zinc hydrometallurgy can be treated by flash magnetization roasting.It can enrich the goethite residue into standard iron ore for sale. It is the best accessible green solution to recycle iron at high efficiency but low cost.

Crude Zinc Oxide (C.Z.O.) is one of the important resource of zinc metal extraction. The main source of crude zinc oxide includes: a. flue dust collected from waste steel recovery; b. fume dust collected from zinc leaching residue treatment by waelz kiln; c. zinc fume dust collected from lead slag treatment by fuming furnace.  

Vanadium recovery process shall be selected as per raw material specification. Metalcess provides solution of alkaline process to reduce inclusion of impurities during leaching while ensures relatively high leaching rate. We can produce high quality V2O5 (higher than 99.95%) through simplified and high efficient process flow. 

Copper smelting slag is produced from copper pyrometallurgy (both smelting and converting stages), usually grading at 0.3-3%. The slag may also contains lead & zinc minerals like galena, sphalerite. Copper mainly dwells in the slag in the form of bornite, chalcocite, chalcopyrite, and metallic copper. The rest are iron minerals like magnetic iron ore, metallic iron and gangue like fayalite, hedenbergite and amorphous phase matter. Such slag can be concentrated by separation and enrichment to obtain copper concentrate.