Patent ID: 7887629

Claim:
A method for preparation of coating compound for the paper industry, comprising: obtaining raw natural calcium carbonate fillers and raw pigments of a basic grade as solids having a mean grain diameter (D 50 ) of 2 μm to 10 μm from suppliers of raw materials; milling said raw natural calcium carbonate fillers and raw pigments in an aqueous phase in-situ at the paper mill to obtain a self-prepared pigment slurry comprising 2-60% fillers and pigments by weight having a desired particle size with a grain distribution of from 10 to 99% by weight of particles <1 μm, respectively based on the equivalent diameter, and employing said self-prepared pigment slurry for the preparation of a coat for paper coating or in the paper stock, wherein said aqueous phase comprises residual water sludges.