Project duration: 1 January 2020 – 31 December 2023
Objective
TETALEAD will increase the raw material efficiency in zinc production by valorising significant amounts of lead, silver and tin contained in leach residues presently landfilled. A de-sulfurization method producing high quality concentrates are developed and patented for industrial implementation and commercialisation. This highly reduces energy consumption and CO2-emission, improves working environment and increases lead product market.
The solution (technology)
There are significant amounts moist leach residue, with valuable contents of lead, silver and tin, generated when extracting zinc. These residues presently go to landfill or are processed via high energy demanding processes emitting CO2, and that also generates new residues as lead containing slag. Via the new low temperature process the residue can be upgraded, without CO2 emission and SO2 (sulphur dioxide) release, into a high value Pb-concentrate that can be processed at moderate temperatures and with little need for refining. This type of concentrate is interesting on a wider market
Lead smelters processing lead containing moist leach residues take treatment fees independent on the lead and silver content, and the fee may be increased if the moisture content is high. Also, there is transportation costs for moving the material from one plant to another and if using seaborne bulk vessels dewatering to < 20% is usually needed.
Low temperature methods using different solutions for dissolving the compounds have been investigated but these are so far not widely spread. In this project a low temperature method already shown to be applicable on lead sulphate originating from lead-acid batteries recycling will be applied after adapting it to specific residues. The method will be up-scaled, demonstrated in an industry relevant environment. A patent application and basic design for industrial installation will support commercialisation and implementation, respectively, within three years from project end. Further, also the most appropriate hydrometallurgical methods among reported for silver and tin will be investigated and applied as well. Achieved knowledge will be disseminated through education for professionals and master students and also via scientific publication in open access journals and conferences gathering targeted users at industry and technology companies that can commercialise the method.
The proposed low temperature method is characterised by low consumption of reagents due to regeneration, almost effluent free process, low energy consumption and high quality products. Compared to the moist leach residue the lead product will have high lead content (70 to 75%) in a carbonate form being possible to process at lower temperature, e.g. in rotary kiln present at recycling companies. Following, the market will be larger and the product having a higher value. Market analyses for the technology and the products (lead, silver and tin products) as well as pre-feasibility study will clarify the economic aspects in terms of market, OPEX, CAPEX, NPV (Net Present Value), IRR (Internal rate return) etc. The environmental impact will be analysed in comparison to present processing route.
Partnership
- Luleå University of Technology (LTU) (Lead Partner), Sweden
- Boliden Commercial AB, Sweden
- Łukasiewicz Research Network – Institute of Non-Ferrous Metals, Poland