Effect of particle size on bioleaching of low-grade nickel ore in a column reactor

Biological column leaching of Ni from low-grade Ni ore was studied, and the effects of ore particle size on leaching rate were investigated. The Ni ore with an average Ni content of 0.23% was crushed into four different particle size fractions: >10 mm, 5–10 mm, 2–5 mm and 10 mm (bioleaching), 5–10 mm (acid leaching), 5–10 mm (bioleaching), and 2–5 mm (bioleaching) were 23.76%, 22.15%, 32.42% and 54.17%, respectively, after 180 d of bioleaching. The ore particle size changed after leaching, compared with the original ore size, the proportion of the same size of 2–5 mm ore decreased to 44.64%. Ore with particle size of 2–5 mm was most suitable for column bioleaching, and effective Ni extraction was achieved with appropriate control of ore granularity.