Mariano P Greco

US Patent:

52905160, Mar 1, 1994

Filed:

Oct 22, 1992

Appl. No.:

7/965058

Inventors:

Mariano Greco - Pittsburgh PA
Brenda Lesperance - Blawnox PA
Grace L. Shine - Gibsonia PA

Assignee:

Bacharach, Inc. - Pittsburgh PA

International Classification:

G01N 3122
G01N 3318

US Classification:

422 57

Abstract:

A method and product whereby color changing indicator salts such as cobaltous salts, preferably CoCl. sub. 2 or CoBr. sub. 2, are firmly adhered to sand, other particulate silicas or other carriers so that unwanted fines, material loss and solvent washing characteristic of prior indicator salt-coated carriers are eliminated. The process is carried out by thoroughly dehydrating a quantity of cobaltous salts and dissolving and storing the dehydrated cobaltous salt in absolute alcohol, preferably absolute ethanol. The absolute alcohol/cobaltous salt solution is then contacted onto a dehydrated or anhydrous carrier material and the absolute alcohol solvent is removed.