The influence of shear rate on the thixotropy of ferric aluminum magnesium hydroxide/Na-montmorillonite suspension

In this paper, the influence of measuring conditions, the shear rate (D-L) used to measure the viscosity of the suspension, on the thixotropy of Fe-Al-Mg-mixed metal hydroxide (MMH)/Na-montmorillonite (MT) system and the pure MT suspensions was studied. It was found that the pure MT suspension and the Fe-Al-Mg-MMH/MT suspensions with MMH/MT mass ratio ( R) = 0.013 displayed positive thixotropy in the studied range of D-L ( 10, 170, 511 and 1 029 s(-1)), i. e. the shear rate did not influence their thixotropic type. The Fe-Al-Mg-MMH/MT suspension with R = 0.051 displayed complex thixotropy at lower D-L ( 10 and 170 s(-1)) and positive thixotropy at higher D-L (511 and 1022 s(-1)), respectively. The Fe-Al-Mg-MMF/MT suspension with R = 0.091 displayed negative thixotropy at lower D-L (10 and 170 s(-1)), and complex thixotropy at higher D-L (511 and 1 022 s - 1), respectively. The viscosity of the suspensions studied decreased gradually with the increase of D-L. Furthermore, the mechanism by which D-L influences the thixotropy of the suspensions is discussed.