Influences of electrolytes, polymers and a surfactant on rheological properties of bentonite-water systems

Characteristic rheological properties, such as viscosity, sheaf stress, yie ld point, gel strength and thixotropy, of natural Ca-bentonite and Na-pepti zed bentonite were studied after adding LiCL, KCl, CaCl2, MgCl2. 6H(2)O ele ctrolytes; (NaPO3)(n), polyvinyl pyrolidone (PVP) polymers and an anionic s urfactant (linear alkyl benzene sulphonate, LABS). Changes in flow properti es under the influence of various additives at different quantities were in vestigated in these slurries. The experimental results are discussed in ter ms of bentonite forms, types and concentrations of additives and influence of exchangeable cations. Bivalent and monovalent cations display entirely d ifferent rheological properties in two,groups of muds. Furthermore, the dif ference in the degree of activity of PVP polymer on the viscosity of two mu d systems depend on the clay mineral structure. The slurry prepared with Na -bentonite contains a minimum number of tactoids and a maximum number of sh eet-bearing clay particles, which reduces the surface area of the clay mine rals and increases viscosity by adding PVP polymer.