| 摘要 |
PROBLEM TO BE SOLVED: To obtain fine crystalline lamellar sodium disilicate having high calcium binding ability, slightly causing a residue on sieve, useful for a detergent, etc. by making the sodium disilicate includeα-sodium disilicate,β-sodium disilicate,δ-sodium disilicate and an amorphous component in a specific ratio. SOLUTION: This fine crystalline lamellar sodium disilicate of the formula (M is sodium or H; (x) is 1.4-4; and (y) is 0-20) comprises 0-40 wt.% ofα-sodium disilicate, 0-40 wt.% ofβ-sodium disilicate, 40-100 wt.% ofδ-sodium disilicate and 0-40 wt.% of an amorphous component but contains no sodium metasilicate. The fine crystalline lamellar sodium disilicate has >170 mg (CaCO3)/g calcium- binding ability at 17 deg. Germany hardness at 30 deg.C and is obtained by grinding sodium phyllosilicate having 80-40μm particle diameter d50 value into <100μm d90 value.
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