Elaboration of industrial material and heat balances as a teaching aid

With today's powerful process simulators, there is no apparent need for students to elaborate detailed material and heat balances for specific plant flow sheets. However, many academic and practical benefits result from this exercise. Firstly, it allows the students to visualize the workings of the entire plant and to grasp the importance of the variables of each unit operation on the overall performance of the proposed scheme. When the balances are programmed in a PC worksheet (e.g. Microsoft EXCEL™), the detailed contents of each flow stream are calculated, allowing the students to better understand the interactions between equipment. Industry could employ the “products” of this activity as training tools and in the evaluation of water balances and detection of possible impurity buildups. Two plant balances are presented: galena leaching with ferric chloride brines and precious metals leaching with ammonium thiosulfate.