Abstract: Nickel hydroxide and cobalt hydroxide slurry neutralization process exist large hysteresis timevarying nonlinear characteristics. When using the existing neutralization process closed loop control methods in the actual application， if the system was affected by random disturbance， then the pH value would deviate from the target value， which would influence on the performance of the subsequent slurry precipitation process， reducing the nickel hydroxide and cobalt hydroxide product quality. The forecast model and fuzzy adaptive control method were combined in order to achieve industrial process control requirement for the pH value. It was demonstrated by the successful application of a large nickel hydroxide and cobalt hydroxide smelter in foreign country that the problems such as large hysteresis timevarying nonlinear characteristics in the neutralization reaction process could be effectively solved based on the proposed method， resulting in the stable running of the nickel hydroxide and cobalt hydroxide slurry neutralization reaction process， and the improvement of the recovery rate of nickel and cobalt metals components.

Key words: slurry neutralization reaction press, FMC(forecast model control), fuzzy adaptive control, time delay system