CHEMICAL TITRATION SIMULATION - AN EQUILIBRIUM CALCULATION APPROACH Hsin-Hsiung Huang, L.G. Twidwell, C.A. Anderson and C.A. Young Metallurgical and Materials Engineering Department Montana Tech of the University of Montana, Butte, MT 59701 ABSTRACT An equilibrium calculational computer program (STABCAL) can be used for titration simulation. The program can handle various forms of titrants: solid, aqueous, gaseous or another solution, and various type of reactions: reductive, oxidative and adsorption. Background chemistry, mathematical considerations, and program development will be illustrated. Also, simple titration applications such as how to determine the acidity of aqueous solutions and alkaline sulfide leaching of gold are presented. Processing of an acid mine water from the Berkeley Pit in Butte, Montana has been used for illustration purposes. The treatment studies included: cementation, sulfidization, and neutralization. The calculational results for the neutralization treatment using various alkaline reagents are compared to actual experimental data and potentially appropriate processes are discussed. Hsin-Hsiung Huang Professor Metallurgical Engineering 1300 W. Park Butte, MT, USA Tel:(406) 496 4139 E-mail:hhuang@mtech.edu Keywords: Water chemistry, equilibrium calculation, chemical titration, acidity and alkalinity, acid and alkaline reactions, reduction and oxidation reactions, and acid mine water.