Experimental Study on the Effect of Cation Exchange Capacity on Slurry Properties

The slurry was prepared by pre-hydration method in this study. The relationship between the content of bentonite in slurry and its cation exchange capacity was studied by changing the content of bentonite. After the density, funnel viscosity, filtrate volume and rheological properties of slurry were tested, the influence of cation exchange capacity on slurry performance and filter-cake quality was analyzed. The results showed that: When the cation exchange capacity of slurry is small, with the increase of cation exchange capacity, the funnel viscosity, apparent viscosity and plastic viscosity of slurry increase significantly, the filtrate volume decreases gradually, and the overall performance improves significantly, which can effectively form filter cake and maintain the stability of excavation surface; while when the cation exchange capacity exceeds a certain value, the funnel viscosity, apparent viscosity and plastic viscosity of slurry increase significantly. With the increase of cation exchange capacity, the filtrate volume and viscosity of the slurry still increase, and the filter cake performance tends to be stable, but its overall performance does not rise but fall. Considering the influence of cation exchange capacity on the slurry performance parameters, when the cation exchange capacity of the slurry is controlled around 7.58 i.e. the solid phase content is between 6% and 7%, the slurry filtrate volume is relatively small, and it is easy to form thin and compact filter cake with its best comprehensive performance.