Abstract:

Alumina sol is widely used in fields such as petrochemical catalysts，high⁃temperature⁃resistant materials，and lithium⁃battery material modification.To address the issues of corrosive gas release，environmental pollution，and poor stability in traditional alumina sol preparation，acetic acid was employed as the peptizer and a powder dispersion method was utilized to synthesize alumina sol.The effect of acid to Al ratios，acid dissolution temperature，acid dissolution time，and alumina content on sol particle size and Zeta potential were investigated.Single⁃factor experiments revealed that the acid to Al ratios and temperature significantly influenced the sol particle size and Zeta potential.Orthogonal experiments further confirmed that alumina content was the key factor affecting sol stability，with the sol tending to gel when the alumina content reached 20%.Innovatively，a dry gel redispersion method was adopted to prepare high⁃concentration alumina sol.The primary alumina sol was dried into a dry gel to remove free acetic acid and then redispersed in water to obtain the secondary alumina sol.The stability tests demonstrated that the particle size of the primary alumina sol was increased from 32.72 nm to 171.72 nm after 60 days，accompanied by gelation.In contrast，the secondary alumina sol，despite having the same or higher alumina content，exhibited no significant particle size change and retained fluidity after 60 days.This study successfully synthesized high⁃concentration alumina sol with up to 30% alumina content and a stability period exceeding 60 days，resolving the problems of gelation and environmental pollution in traditional alumina sol preparation and lay a foundation for further industrial⁃scale production.

Key words: alumina sol, pseudo?boehmite, acetic acid, high alumina content