Experience with Digital Process Optimization of Zinc Roasting Plants

摘要

Operation of zinc roasting plants has always been a challenge for changing feed mixtures and difficult concentrate qualities. Especially very fine particle sizes and increased amount of impurities like Pb and Cu require a higher attention of the control room operator to run the plant in stable conditions. As a result of this manual roasting plant control, the operation campaigns get interrupted by unplanned shutdowns due to poor roaster bed fluidization. In addition, the production targets and product quality are difficult to reach. Therefore, plant availability becomes more of a focus than other key production indicators (KPI). Operating the complete process chain consisting of zinc roasting furnace-gas cleaning and acid plants in desirable operating conditions is subject to many factors such as feed, air, and oxygen flow as well as water addition at different positions and many more. Operating the roaster in a stable and profitable operating window requires careful, regular, and anticipatory adjustment of these parameters. To support the operation of such plants, Outotec has developed and commissioned the Pretium Roaster Optimizer, a system that continuously leverages embedded process know-how to operate the roaster in an optimal way for high process efficiency, a consistently high product quality and improved economical KPIs. This chapter gives a short review on the application of modern advanced automation and optimization methods to improve metallurgical process plant operations and in specific the zinc roasting process.