Abstract
A series of experiments on the leaching of Garnierite ore with H2SO4 solution were carried out to investigate the effects of the some addition of fluoride and chloride to the leaching medium and roasting of the ore in air on the extraction of Ni, Mg, Fe and Si from the ore.
The addition of NaF (about 2 weight % of the ore), increase the extraction rate of Ni and Mg at 305 and 315K. The addition of CaF2 also increase the extraction rate, but the addition of NaCl has no effect on the extraction rate.
By roasting ore antigorite, chrysotile and goethite are decomposed, to form forsterite, enstatite, hematite, magnetite, maghemite in the ore as the roasting temperature is heightened and also, free state MgO is formed in the ore, and the quantity is closely related to roasting temperature and reaches the maximum at 973K.
In H2SO4 leaching, the roasting of the ore significantly promotes the extraction rate of Ni, Mg, Fe and Si from the ore at 305K.
