Method of preparing loosely aggregated 200-500 millimicron silica
AssigneeW. R. Grace & Co.
InventorsEllsworth George Acker, Milton Edward Winyall
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Abstract
A loosely aggregated 200-500 millimicron primary particle size silica can be produced by a silicate neutralization technique. The process consists of neutralizing an alkali metal silicate solution by addition to an ammoniated acetic acid or carbonic acid mixture. These particles are loosely aggregated to an average particle size of about 1 micron. These particles are readily deaggregated in a fluid energy mill. A very convenient technique is to dry and deaggregate in a fluid energy mill in a single step.
Claims6
A method of producing loosely aggregated silica having an average primary particle size in the range of 200 to 500 millimicrons comprising adding an alkali metal silicate solution to an ammoniated gelling solution selected from the group consisting of an ammoniated formic acid solution, an ammoniated acetic acid solution, an ammoniated propionic acid solution and an ammoniated carbonic acid solution, said ammoniated gelling solution containing a substantial excess of ammonia and having a pH of 10 to 11, to form a slurry of said loosely aggregated silica and recovering said loosely aggregated silica.
Dependencies are inferred from the claim text.