BioZinGa - New source of rare metals
Critical raw materials such as zinc, indium and gallium are vital to securing Europe’s competitive advantage. They are needed by high-tech industry and this need is growing; however, their extraction is expensive. In tailings, i.e. the fine-grained mining residue in sludge after processing ores, zinc & co. remain partly unexploited.
The usual extraction methods are cost-intensive; in the case of zinc, a combination of pyro-metallurgic and hydro-metallurgic techniques are required. An extremely promising new way allows zinc, indium and gallium to be recovered from the tailings by means of bioleaching.
The project investigated an optimized possibility to extract metals with bioleaching. But first, several preparation steps were necessary to avoid damage to bacterial cultures.
Recovering method in lab scale
Among other things, bacterial cultures best suited for leaching had to be determined; ideal parameters such as pH-value and temperature defined; and ways sought to remove barren rock and interfering elements. Furthermore, it was examined how valuable metals could be enriched prior to leaching, because smaller amounts of material reduce costs. The savings are achieved by using fewer consumables and correctly dimensioned equipment.
The challenge was the interplay of various disciplines such as mineral beneficiation, metallurgy, chemistry, biology and plant engineering. In the end, a recovering process to extract metal from tailings was successfully developed in lab scale. Based on the results to date, a plant design will be set up as a basis for assessing the cost effectiveness of the researched processes.
With this project, Austria firmly establishes itself as an expert in the field of extracting critical metals, increases its competitiveness and contributes to sustainability and environmental protection by recovering raw materials.
Other Consortium Partners
- PROFACTOR GmbH
- Technisches Büro – Dr. Kolb
- SPIEGLtec GmbH