Effect of Lignosulfonate on Viscosities of Suspensions of Montmorillonite

Abstract

The viscosities of dilute suspensions in both pure and electrolyte-containing water of H-, Na-, Ca- and Al-montmorillonite were measured with the addition of lignosulfonate (LSA) of an average molecular weight of about 36000.
The limiting viscosity number [η] and the viscosity number ηsp/c (c=O.005 g-clay/ml) were determined and the influence of the added LSA on the modes ofparticle association in the clay suspensions was discussed. With respect to the dilute suspension of clay, it is possible to take [η] and ηsp/c for a parameter of the average shape factor of clay particles including the aggregates at infinite dilution and some arbitrarily chosen concentration of the clay, respectively.
The shape factor for all the systems of the suspensions except for both the Na-Water-8 and Na-NaCl-10 systems was decreased by addition of the LSA though there was difference in its degree. From the values of [η], ηsp/cand the data for the adsorption of the LSA on the montmorillonites, it is concluded that the effect of the LSA on the shape factor is mainly due to the decrease of the edge-to-face association of the clay particles by the adsorption of theLSA on the edge of the particles. And then, for the systems of Na-NaCl and Na-NaCl-10, Ca-CaC12, Al-AlCl3 and Al-Water, it seems that the formation of face-to-face assosiation is hindered by the added LSA.