Detoxification of chromium-containing slag by Achromobacter sp. CH-1 and selective recovery of chromium

Based on the principle of bacterial leaching and bacterial metallurgy, a novel technology for the detoxification of chromium-containing slag by Achromobacter sp. CH-1 and chromium recovery was proposed. Strain CH-1 cell morphology before and after Cr(VI) reduction was observed with a scanning electron microscope (SEM), and the reduction product is found to adhere to terminals of CH-1 cells. Energy-dispersive X-ray (EDX) and electron paramagnetic resonance (EPR) analyses reveal that the main component of the reduction product is Cr(VI). Furthermore, small and large-scale demonstration projects reveal that Achromobacter sp. can be used to detoxify chromium-containing slag and to selectively recover chromium by using this novel technique. Chromium recovery rate increases with decreasing particle sizes of chromium-containing slag and slagheap height. Chromium recovery rates in 10 t/batch and 20 t/batch of on-site demonstration projects for chromium-containing slag detoxification are more than 90%.