Process for making sodium tripolyphosphate
AssigneeFMC Corporation
InventorLawrence A. Shimp
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Abstract
A one step spray drying process for making high assay sodium tripolyphosphate having a high concentration of form I material by spray drying an aqueous sodium orthophosphate feed liquor having an Na.sub.2 O:P.sub.2 O.sub.5 ratio of 1.60 to 1.70 at a temperature between 250.degree. and 420.degree. C. for up to one minute to produce sodium tripolyphosphate and cooling the product to 150.degree. C. or below in twenty minutes or less.
Claims4
A one step spray drying process for making high assay, 90% or greater, sodium tripolyphosphate having a high concentration, greater than 75%, of form I material consisting essentially of the steps of spraying an aqueous sodium orthophosphate feed liquor having an Na.sub.2 O:P.sub.2 O.sub.5 ratio of 1.60 to 1.70 into a spray dryer, dehydrating the sprayed feed to a temperature above 250 and below 420.degree. C. in a period of up to one minute to produce sodium tripolyphosphate, removing the product sodium tripolyphosphate, which has a temperature below 420.degree. C., from the dryer and cooling the product to 150.degree. C. or below in twenty minutes or less.
Dependencies are inferred from the claim text.