Abstract: In order to unveil the rheological properties of suspensions of montmorillonite(MT) and its mixture with sodium carboxymethyl cellulose(CMC)/MT, the effects of the mass fraction w of MT, mass ratio R of CMC to MT, electrolyte, pH and experimental temperature on such properties have been systematically studied. When w(MT) was increased from 1.0% to 3.0%, pure MT suspension changed from Newtonian-like fluid to plastic one, and the thixotropic type changed from non-thixotropy to positive thixotropy and then a complex one. For CMC/MT plastic suspension, the increase of R(fixing w(MT)=2.0% in all the systems) would cause the yield value(τ0) and consistency coefficient(K) to increase as well. The hysteresis loop area(S) increased initially and then decreased, which was accompanied with a synchronous variation of the absolute zeta potential value(|ζ|). The plastic and thixotropic characters of CMC/MT suspension could not be altered by either the electrolytes or experimental temperature investigated. But the yield value τ0 and consistency coefficient K would increase with the increase of electrolyte(NaCl, MgCl2 and AlCl3) concentrations or the decrease of experimental temperature. With the increase of pH value of CMC/MT suspension, its thixotropic type was transformed from negative into positive and the |ζ| incresesd, meanwhile the S firstly increased and then decreased and its maximum value was reached at pH=8.46.

Key words: montmorillonite, sodium carboxymethyl cellulose, rheology, Thixotropy, Hysteresis loop