Process systems engineering and mineral industries: Flexibility analysis in a flotation circuit

The goal of a process design is to produce a plant that is optimal with respect to cost and performance. A good design should also exhibit operability characteristics that allow economic performance to be realisable in a practical operating environment. The aim of this research is to establish an investigation of operability, especially flexibility, of a flotation plant. Several flotation circuits have been considered for this study, which are different in structure. A superstructure that contains all these alternatives is built and an :MINLP program is setup. Using GAMS optimisation package with DICOPT as the solver, the best flowsheet that maximises the recovery of the valuable mineral is found. The next step involves the flexibility analysis of the best four flowsheets using a systematic algorithm. It is found that the most flexible plant is not necessarily the flowsheet found in the synthesis stage, confirming the fact that by including such flexibility at the design phase one can often avoid costly changes needed later to reduce product variability.