Patent ID: 9556320
Date: 2017-01-31
CPC Classifications: C01P,C08K,C08L,C09C,D21H,G01N,G06K

Claim:
1. A process for improving the whitening of a mineral matter slurry surface by reducing flotation of impurities to the slurry surface which cause darkening of the slurry surface, the process comprising the following steps: (a) preparing by dispersing and/or grinding at least one water based mineral matter slurry, wherein the mineral matter comprises calcium carbonate and impurities that can cause darkening of a slurry surface, wherein the impurities comprise one or more oxides, sulphides, silicates, and crystalline and/or amorphous carbon; and (b) adding to the slurry during and/or after step a), 0.005 wt % to 0.5 wt %, based on dry weight of the mineral matter, of at least one alkylene oxide block co-polymer or at least one alkylene oxide random co-polymer, to obtain a slurry of mineral matter in which the slurry surface has improved surface whiteness over the same slurry in which the at least one alkylene oxide block co-polymer or the at least one alkylene oxide random co-polymer is not added, wherein the whitening of the slurry surface is improved by reducing flotation of impurities to the slurry surface which cause darkening of the slurry surface.