Optimal Control of Oxidizing Rate for Iron Precipitation Process in Zinc Hydrometallurgy

In the iron removal process in zinc hydrometallurgy, the reaction conditions to form goethite precipitate are difficult to achieve, in which the oxidizing rate of ferrous ion has to be strictly controlled to remove the iron ion from leach solution by goethite. On the basis of dynamic model for iron removal process and according to the forming conditions of goethite precipitate and procedure requirements, the optimal setting model of reactor outlet ferrous ion concentration is investigated in this paper. An optimal control model of oxidizing rate for iron precipitation process is established. The optimal control problem is transformed to a nonlinear mathematical programming problem by control parameterization method. The mathematical programming problem is then solved utilizing state transition optimization algorithm to obtain the optimal control of oxygen and zinc oxide to make the oxidizing rate in the best conditions of forming goethite precipitate. Numerical simulations validate that the optimal control of oxidizing rate can not only satisfy the forming conditions of goethite precipitate but also stabilize the production process.