Residues from Hydrometallurgical Zinc industry as a Promising Source of Lead and Silver
The ever-growing demand of raw materials, especially metals, makes it necessary to use more and more deposits and ores of decreasing quality. This causes an increasing amount of waste material that must be dumped. Moreover, these residues often contain considerable amounts of various metals such as lead, zinc and silver that are costly mined somewhere else. One reason for this paradox is that the metals in these residues are often somehow bound to many different phases. In hydrometallurgical residues from zinc producing industry. for example, it is very common that lead occurs as an oxide, sulfate and sulfide compound within the same material. Due to the variety and complexity of such materials, they cannot be won economically by common metallurgical techniques. Developing new methods or adapting old ones requires detailed knowledge of the characteristics of the materials. Characterization of input material is state-of-the art for primary resources but not for metallurgical or mining residues. Quite often, lead and silver are essential metals in different by-products in terms of process economy and applicable technology. In contrast to natural ores, process residues often contain phases that are somewhat difficult to characterize as they are in many cases amorphous, non-natural and very small grained. Common techniques of determining characteristics that are important for any kind of treatment in terms of mineral processing and metallurgy often show up their limits when applied on such materials. As discussed in this presentation, the target of this research is developing a characterization procedure that can be used for different kinds of metallurgical and mine residues. In fact, leaching residues and precipitation products from hydrometallurgical zinc-winning are in focus of research. The products are often rich in many different metals, especially lead, zinc, copper and silver. To date, many metal-bearing phases have been identified.
Gustav Hanke is a graduate of the University of Graz. In 2016, he began his PhD studies at Montanuniversität Leoben and changed his research focus from neotectonics to the characterisation of metallurgical by-products, especially those found in the zinc industry. Gustav works in close cooperation with specialists in mineral processing, metallurgy and various industrial partners from Europe and Africa and supports several industry-related projects.