| 摘要 |
PROBLEM TO BE SOLVED: To obtain an activated clay exhibiting excellent decoloring ability, coloring ability and coating property with a small quantity to be used and small in oil retention by treating a specific dioctahedral type smectite clay mineral with an acid. SOLUTION: The dioctahethal type smectite clay mineral having 15-30 nm, pcticularly 20-28 nm crystallite size (R10 ) obtained from the half-width of x-ray diffraction peak of the face index (06) of the smectite and 100-230 nm<2> , particularly 120-230 nm<2> crystallite cross-sectional area (V0 ) defined by an equation V0 =R10 ×R20 (R20 represents a crystallite size (nm) obtained from the half-width of X-ray diffraction of the face index (001) of smectite measured in the ethylene glycol treated state) is treated with the acid. The activated clay having 10-30 nm crystallite size (R1 ) obtained from the half-width of X-ray diffraction peak of face index (06) of smectite, 60-150 nm<2> , particularly 60-145 nm<2> crystallite cross-sectional area (V1 ) defined by an equation, V1 =R1 ×R2 (R2 is R20 ) and 250-350 m<2> /g BET specific surface area is obtained. |
