PRODUCTION OF HIGHLY DISPERSIBLE MAGNESIUM HYDROXIDE

PURPOSE:To obtain in an industrially and economically efficient manner the title magnesium hydroxide useful as e.g., a flame-retardant for polyolefin, by hydrating specific fine powder in the presence of a magnesium salt. CONSTITUTION:First, Mg(OH)2 containing <=0.1wt.% of Ca ion is calcined at 1...

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Bibliographic Details
Main Authors UCHIDA TOYOTAKA, ICHIMURA YOJIRO, IWAMOTO KAZUHIKO
Format Patent
LanguageEnglish
Published 23.05.1989
Subjects
CHEMISTRY
COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM,CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THERARE-EARTH METALS
INORGANIC CHEMISTRY
METALLURGY
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Summary:PURPOSE:To obtain in an industrially and economically efficient manner the title magnesium hydroxide useful as e.g., a flame-retardant for polyolefin, by hydrating specific fine powder in the presence of a magnesium salt. CONSTITUTION:First, Mg(OH)2 containing <=0.1wt.% of Ca ion is calcined at 1,150 to 1,350 deg.C to produce MgO. Secondly, this MgO is ground using e.g., a ball mill to produce MgO fine powder having the following characteristics: (1) crystallite diameter in the direction... 800 to 1,500Angstrom (2) BET specific surface area... 0.7 to 2m /g (3) average particle size... 2 to 5mum (4) purity... >=98wt.%. Thirdly, a liquid to be subjected to hydration is prepared by incorporating water with this MgO and a Mg salt such as MgCl2 or magnesium acetate so that their concentrations fall between 100 and 300g/l and between 0.02 and 0.3mole/l respectively. Finally, this liquid is subjected to hydration at 70 to 95 deg.C for 1 to 4hrs to obtain the objective highly dispersible magnesium hydroxide.
Bibliography:Application Number: JP19870290266