Patent ID: 8662311
Filing Date: 2014-03-04
Classification: B03D,C22B

Abstract:
1. A process for separating silicates and alkaline earth metal carbonates, wherein the process comprises the following steps: a) providing at least one mineral material comprising at least one silicate and at least one alkaline earth metal carbonate, said mineral material having a weight median grain diameter in the range of from 5 to 1000 μm; b) providing at least one hydrophobically modified polyalkyleneimine, wherein: c) contacting said mineral material(s) of step a) with said hydrophobically modified polyalkyleneimine(s) of step b), in one or more steps, in an aqueous environment to form an aqueous suspension having a pH of between 7 and 10; d) passing a gas through the suspension of step c); e) recovering an alkaline earth metal carbonate-containing product and a silicate-containing product from the suspension; f) raising the pH of the silicate of step e) in an aqueous environment by at least 0.5 pH units to desorb all or part of the hydrophobically modified polyalkyleneimine(s) from the silicate fraction and extracting the hydrophobically modified polyalkyeleneimine(s) into the washing liquid; and g) treating the liquid fraction of step f) with an acid to reduce the pH of this liquid fraction by at least 0.5 pH units.