Monsanto Company

James E Downes

Vaidy R Nathan

John R Jany

John T Wang

Alan W Seder

Substantially crystalline calcium sodium metaphosphate having a degree of crystallinity from about 60% to about 75% as determined from density and differential thermal analysis measurements is prepared by (a) forming a dry mixture of source materials for CaO, Na.sub.2 O, and P.sub.2 O.sub.5 in proportions sufficient to provide a CaO/Na.sub.2 O/P.sub.2 O.sub.5 mol percent ratio on a dry basis of about 29.0-34.0/16.0-18.0/50.0-53.0 and (b) heating the mixture at a temperature and for a time sufficient devolatilize the mixture and calcine the resulting mixture to form the substantially crystalline calcium soldium metaphosphate.

Process for the preparation of substantially crystalline calcium sodium

Substantially crystalline calcium sodium metaphosphate having a degree of crystallinity from about 60% to about 75% as determined from density and differential thermal analysis measurements is prepared by (a) bringing together in water source materials for CaO, Na.sub.2 O, and P.sub.2 O.sub.5 in proportions sufficient to provide a CaO/Na.sub.2 O/P.sub.2 O.sub.5 mol percent ratio on a dry basis of about 29.0-34.0/16.0-18.0/50.0-53.0 and form a wet mix slurry containing a solid phase and an aqueous liquid phase and (b) heating the wet mix slurry at a temperature and for a time sufficient to remove the aqueous liquid phase and calcine the resulting solid phase to form the substantially crystalline calcium sodium metaphosphate.

Asbestiform crystalline calcium sodium metaphosphate fibers are prepared by (a) forming a homogeneous melt of substantially crystalline calcium sodium metaphosphate having a composition on a dry basis equivalent to a CaO/Na.sub.2 O/P.sub.2 O.sub.5 mol percent ratio of about 29.0-34.0/16.0-18.0/50.0-53.0 and a degree of crystallinity from about 60% to about 75% as determined from density and differential thermal analysis measurements, (b) supercooling the homogeneous melt, (c) seeding the supercool melt with calcium sodium metaphosphate crystals, (d) maintaining the seeded supercooled melt at the seeding temperature under isothermal conditions for a time sufficient to form crystalline blocks of calcium sodium metaphosphate, and (e) fiberizing the crystalline blocks.

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St. Louis, MO, United States of America

James E Downes