Michael A Howe

US Patent:

44434251, Apr 17, 1984

Filed:

Dec 9, 1981

Appl. No.:

6/328965

Inventors:

Samuel W. Sopp - Foster City CA
Leonard S. Lee - South San Francisco CA
Michael W. Howe - Albany CA

Assignee:

Calgon Corporation - Pittsburgh PA

International Classification:

C01F 506

US Classification:

423635

Abstract:

The instant invention is directed to a magnesium oxide composition, for use in coating silicon steel, having a Citric Acid Activity of 50 to 200 seconds and a particle size of 90 percent finer than 325 mesh prepared from a blend of (a) ground magnesium oxide having a Citric Acid Activity of greater than 200 to 2000 seconds and (b) ground magnesium oxide having a Citric Acid Activity of 40 to 100 seconds. The instant invention is also directed to a process for the production of a magnesium oxide composition, for use in coating silicon steel, having a Citric Acid Activity of 50 to 200 seconds and a particle size of 90 percent finer than 325 mesh, comprising: (a) grinding to a 90 percent finer than 325 mesh (i) 20 to 60 percent by weight of a ground magnesium oxide having a Citric Acid Activity of greater than 200 to 2000 seconds and (ii) 40 to 80 percent by weight of a magnesium oxide having a Citric Acid Activity of 40 to 100 seconds and (b) blending (i) and (ii) together.