The key technical index

namely

alkaline solution concentration of alumina evaporation process

can not be measured on-line.Moreover

it is usually difficult to describe the dynamics characteristic between the techniques indices and the control loops by using an accurate mathematical model.Thus

the existing optimal methods can not solve the optimal control for operation of the alumina evaporation process.In this paper

a hybrid intelligent optimal control method is developed.The proposed method is comprised of a presetting model based on case-base reasoning (CBR)

soft sensor model based on recursive partial least squares (RPLS)

feedforward and feedback compensators based on expert rules.Simulation is researched by the actual data of the alumina evaporation process.The simulation results show that the proposed methods can control the alkaline solution concentration within their scopes.