HYDROMETALLURGICAL ZINC PRODUCTION - ENVIRONMENTAL AND EXERGY ANALYSIS

The metallurgical industry is characterized by significant consumption of material and energy resources. The natural resources used are primarily non-renewable. The hydrometallurgical zinc extraction is distinguished by a variety of processes and equipment, possible options for replacing some of them with more efficient ones, opportunities for maximum utilization of energy resources. The object of the present analysis is the actually functioning chemical-technological system - KCM - SA, Plovdiv. The fundamental production units, namely roasting of zinc sulphide concentrates, sulphuric acid leaching of the obtained calcine, electrowinning of zinc, ecologically oriented units - processing SO2 - containing gases to sulfuric acid and waste zinc cakes via Waelz process, as well as the system as a whole, have been analysed. The exergy method of thermodynamic analysis was applied as a research method. The obtained results are compared with those from our previous studies, as well as with literature data on similar processes. Higher energy-technological efficiency and reduction of the harmful impact on the environment can be achieved by increasing the share of renewable energy resources and processed secondary raw materials and reducing specific energy consumption.