Techno-economic assessment of the process for recovery of indium, germanium and tin from alloys obtained as byproducts of zinc production: Master's thesis

A techno-economic assessment for a process for recovery of indium, germanium and tin was conducted. The proposed process involves the use of both pyroand hydrometallurgical methods to recover the metals from two lead-bearing alloys, which are obtained as byproducts in zinc production. Lead-tin alloy, germanium concentrate and two different indium concentrates are obtained as main products in the process. Additionally, a literature review of the indium, germanium and tin markets was conducted, with the main purpose to provide a background for the metals which market prices the profitability of an investment in the process relies on. The proposed concept was simulated to provide mass and energy balances for the process. The mass distribution of elements, obtained from pilot-scale experiments performed by the research institute IMN, was used as input data in the process simulation. Using the mass balances obtained from the simulation, the main equipment required for the process was dimensioned. The capital cost, the operational costs and the revenue for the process were estimated and using these, the net present value of the investment was calculated for a time period of 20 years. A sensitivity analysis was conducted by varying the estimation of metal prices and selected costs and studying its impact on the net present value.
For a revenue equaling 70% of the pure metal value of the products and a capacity of 280 t alloy per year, the net present value of the investment is 3.5 million EUR and the payback time is seven years. The net present value is the most sensitive for variation of the germanium price and for variation of the capacity. A higher capacity would increase the net present value substantially.