Bonding adjuvants for vitreous bond formulations and process for bonding with

A bonding adjuvant for vitreous bonds which comprises:

• a. about 35 to about 45 weight % of a 30% solids silica sol;
• b. about 65 to about 55 weight % of an organic binding agent selected from dextrin and starch;
• and
• c. from about 10 up to about 20 weight %, based on the solids content of the adjuvant, of boron oxide.

A process for the bonding of aluminous abrasive grits which comprises:

• (a) treating the grits with a bonding adjuvant which comprises a silica sol, an organic binding agent effective to enhance bonding of the silica to the surface of aluminous abrasive grits and an additive selected from the group consisting of boron oxide and malic acid, in proportions to provide the adjuvant with from about 10 to about 30 wt. % of silica, from about 30 to about 50 wt. % of organic binding agent, and from about 10 to about 30 weight % of additive , all proportions being based on the solids content of the adjuvant;
• (b) mixing the treated grits with a vitreous bond material;
• and
• (c) forming the mixture of bond and treated grits into a shape and firing to produce a bonded abrasive product.