PhytoGerm: extraction of germanium from biomass:an economic pre-feasibility study

Germanium is a metalloid with great potential for industrial use. Currently, the semiconductor is primarily recovered as a by-product during the exploitation of zinc. The global zinc mine and metal production, however, has been decreasing over the last years, which may result in a production to consumption deficit for germanium. “PhytoGerm” is part of the r³-initiative for tech metals and resource efficiency, a subsidy program of the German Federal Ministry of Education and Research. Within this context, the PhytoGerm project focuses on alternative methods to extract germanium. The suggested mining process operates with ribbon grass which is capable of accumulating germanium from soils, e.g. from mine tailings. After harvesting germanium-enriched plants, the biomass is ensiled and biogas is produced by fermentation. This study analyzes the economic pre-feasibility of this process, whereby the results reveal that germanium can be obtained economically by means of phytomining under certain preconditions (i.e. absorption of 10 ppm germanium in dry biomass, twice the current price of germanium(IV)-oxide)