BASF patents kaolin pigments

Patent No. U.S. 7,494,541 B2
BASF Corporation has received a patent for a method of processing kaolin comprised sequentially: providing a kaolin crude comprising higher amount of gray kaolin and a lower amount of white kaolin; degritting the kaolin crude; subject the degritted kaolin crude to flotation to provide a kaolin having reduced titania content; ozonating the kaolin having reduced titania content; centrifuging the kaolin at high speeds to provide a coarse stream and fine stream, the course stream is comprised of kaolin wherein at least approximately 70% by weight has a size of 2 microns or less, the fine stream is comprised of kaolin wherein at least 80% by weight has a size of one micron or less; refining the coarse stream into a coarse engineered kaolin pigment, wherein the coarse engineered kaolin pigment has a surface area from approximately 15-19 m2/g and 0.75% by weight or less of titania; and refining the fine stream into a fine glossing kaolin pigment; with the proviso that the method does not comprise fractioning the kaolin.