Patent ID: 7763221

Claim:
A process for complete utilisation of olivine constituents, the process comprising the following steps: a) reacting olivine with up to 36 weight % HCl in a reactor, providing MgCl 2 brine, removing impurities, b) separating silica from the MgCl 2 brine and further treating the silica according to its applications, c) removing more impurity particles which together with impurities from the above reacting step, a) can be utilised as a sand product, d) oxidation of the brine by air and KMnO 4 or an oxidant other than KMnO 4 and correction of the pH, e) separating the brine and precipitated Fe and Ni compounds by means of adding flocculant prior to a suitable solid/liquid separation equipment, f) further purifying the MgCl 2 brine using trivalent Fe substance, thereby adjusting Fe/Ni ratio to be higher than 120, adding alkaline substance(s) and/or other chemicals to adjust the brine composition and pH, and separating the impurities by a suitable solid/liquid separation equipment to form a filter cake, g) adjusting the pH of the liquid resulting from step f) using HCl to produce purified MgCl 2 brine applicable for Mg production, h) leaching of the Fe and Ni precipitate from step e) using an appropriate acid, at a suitable temperature, to separate a Ni leaching extract from Fe solids, i) mixing the resulting Fe solids from the previous step h) with the filter cake from the purifying step f) followed by forming a Fe oxide product, j) adding alkalines to the Ni leaching extract from step h) adjusting the pH, and after separation of a Ni solid compound, returning the brine to step d), k) and finally re-dissolving the Ni solid compound, using an appropriate acid, and precipitate a Ni product as carbonate.