Effects of Additives on Gelation Process and Rheological Behavior of Acid Silica Sol and Slurry

Abstract

Abstract: Taking acid silica sol and its bonded slurry as the research object, the effects of additives (polyacrylamide, magnesium hydroxide, and triammonium citrate) on the rheological behavior and gelation process of acid silica sol and its bonded slurry were researched by comparing rheological parameters, such as gelation time, viscosity, thixotropic area, and shear stress. The results show that Mg²⁺ ionized by magnesium hydroxide promotes the condensation reaction of acid silica sol, and presents significant effects on the gelation process of acid silica sol. And the increase of magnesium hydroxide addition increases the gelation speed and decreases the stability of acid silica sol.As an anionic surfactant, polyacrylamide associates the hydrogen bonds to form a three-dimensional network structure in the sol through steric hindrance. At the same time, polyacrylamide is hydrolyzed and adsorbed on the surface of the sol micelle particles, which accelerates the flocculation of SiO₂ particles, and increases the viscosity of acid silica sol and its bonded slurry. Addition of triammonium citrate below 10 mg/mL is conductive to the lowered viscosity and enhanced stability of silica sol bonded slurry.

Key words: monolithic refractory, acid silica sol, slurry, binder, additive, viscosity, thixotropy, stability

CLC Number:

TQ175

YANG Yufei, LIU Hao, WANG Zhoufu, LIU Wenyuan, MA Yan, WANG Xitang, LIU Maolin. Effects of Additives on Gelation Process and Rheological Behavior of Acid Silica Sol and Slurry[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(10): 3292-3297.

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