the invention is directed to a process for separating bitumen froth into an upper bitumen - rich , reduced - solids layer , and a lower concentrated solids layer using a cone - bottomed , raked froth tank . the process involves introducing bitumen froth into the froth tank ; rotating at least one movable picket through the bitumen froth ; recovering the upper bitumen - rich , reduced - solids layer ; and withdrawing the lower concentrated solids layer from the tank .