Analysis of size-strength trade-off in green pelletization for manganese concentrate using multiobjective evolutionary algorithm (NSGA-II)

Adequate supply of desired quality wet pellets governs the productivity of plant operations. Among the many characteristics of pellets, its size and strength are of great importance and considered to be inversely proportional to each other. Most of the researchers analyzed these two properties separately and very few studies tried to understand the trade-off that exists between them. In the present study, an effort has been made to investigate the compromise between pellet size and strength and determine the process parameters that characterize this trade-off. A material system of manganese concentrate is examined and mathematical functions are derived for pellet size and strength in terms of three operating parameters - moisture content, disc inclination and disc rotational speed. These fitness functions are then supplied to NSGA-II, a multiobjective evolutionary algorithm, to produce pareto-optimal (PO) solutions for conflicting objectives. The optimization results confirm the trade-off and the obtained PO solutions signify the characterizing process variables that influence the trade-off.