초록 ▼

A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO2. After separating the stained TiO2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produc

A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO2. After separating the stained TiO2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produce a low brightness pigment suitable of many applications where lower brightness is desirable, such as coating paper board without mottling.

대표청구항 ▼

A method for producing a low brightness, high yellow index kaolin pigment slurry from a kaolin clay containing iron-stained TiO2, the method comprising: dispersing the kaolin clay in water to form a kaolin dispersion; separating the kaolin dispersion into an aqueous high brightness fraction and an a

A method for producing a low brightness, high yellow index kaolin pigment slurry from a kaolin clay containing iron-stained TiO2, the method comprising: dispersing the kaolin clay in water to form a kaolin dispersion; separating the kaolin dispersion into an aqueous high brightness fraction and an aqueous lower brightness fraction, the lower brightness fraction having a TiO2 content substantially between 5-12 % by weight dry clay and an Fe2O3 content substantially between 0.5-2.5% by weight dry clay; concentrating the lower brightness fraction to form a kaolin suspension containing kaolin particles and iron-stained TiO2 particles; wherein the step of concentrating includes flocculating at least a portion of the iron-stained TiO2 particles and the kaolin particles from the lower brightness fraction with a flocculating agent; and recovering the flocculent containing the TiO2 and kaolin particles by hydroseparation to form a recovered kaolin suspension; and washing the recovered kaolin suspension to remove excess salts to form said kaolin pigment slurry; and wherein the washing step includes, dispersing the recovered kaolin suspension with a dispersion agent; diluting the dispersed kaolin suspension; flocculating the diluted suspension; and filtering the flocculated suspension to form a filter cake thereby removing excess salts and dispersing the filter cake with a dispersing agent to form the kaolin pigment slurry.