Washing characteristics of copper-containing clay sludge cake

This paper provides the first report on the novel washing characteristics of copper-containing clay sludge cake, which consists of a second effluent plateau concentration regime. The occurrence of such a second constant concentration regime at elevated pHs is proposed as the consequence of dissolution of cupric hydroxides precipitate that has formed and absorbed onto the clay particles. A new washing model is developed and numerically solved. Numerical results can well describe the experimental data.