Eco-friendly extraction of chromium from calcium-free roasting slag of chromite ore
Calcium-free oxidative roasting of chromite ore and water leaching is the mainstream process of chromium salt production,but there is still a certain amount of residual chromite ore and some newly generated chromium-containing min-erals in the chromite ore processing residue(COPR).Research on the eco-friendly process of deep extraction of chromium from the COPR will be very important to the comprehensive utilization of resources.An eco-friendly extraction process of chromium salt from the COPR was proposed.The research results showed that the chromium could be extracted by an eco-friendly alkali roasting-water quenching process,and this new process could not only reduce the roasting reaction tempera-ture,but also eliminate CO2 produced in traditional roasting process.The extraction rate of chromium reached more than 92%,and the Cr(Ⅵ)in the leached chromium slag was reduced to 3.85 mg/L.The kinetics of the oxidative roasting of chro-mium was controlled by internal diffusion with a frequency factor A of 0.39 s-1 and an apparent activation energy of the reac-tion Ea of 15.22 kJ/mol.The obtained results could provide new technical ideas for deep extraction of chromium from COPR using an eco-friendly process.
chromite oreextraction of chromiumchromite ore processing residueeco-friendly extraction
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