The PH Value Control And Application For The Process Of Iron Precipitation

Abstract:The iron precipitation is a key process of hydrometallurgy, in which oxygen are added to zinc sulfate solution firstly to make the ferrous ions to be the ferric ions, and zinc calcines are added to zinc sulfate solution to adjust pH value to precipitate the ferric ions as goethite precipitation. The iron precipitation needs strictly pH value, high or low pH value is bad for iron precipitation. Actually, because of the late detection of pH value, tempature, oxygen, iron ions and copper ions, workers usually according to their experience to add more oxygen and zinc calcines to insure the iron ions’s precipitation and the pH value, which not only waste the oxygen and zinc calcines but also make the control of pH value lately and volatility. So the relationship of the reactions during iron precipitation is important to build the pH value feedforward control model to control the pH value stably.First of all, we analyzed the the process of iron precipitation and the kinetics of the reactions of iron precipitation, insure the main actors of the pH value control. Then, according to the relationship of the reaction of iron precipitation and material balance in the ractor to build the pH value feedforward control model, which will be used to calculate the zinc calcines should be added. The last, using a new parameter self-tunning fuzzy controller to add extra zinc calcines. The controller’s effectiveness was proved through the simulation, so as to lay a foundation for the realization of stability control of pH value.In order to the automation of stability control of pH value of iron precipitation, using the modular design principle, designed and developed a system of pH stability control of iron precipitation which based on Visual C++and SQL Server database. The system has realized the real-time monitoring of the process, how to add the zinc calcines, query data and other functions.