Finite element analysis of briquetting of iron ore fines

Briquetting is a continuous compaction process to transform loose powders into solid briquettes. The density and strength of formed briquettes vary significantly in the process, affecting the quality of products. This work presented a numerical modelling of briquetting based on Finite Element Method (FEM), focusing on the evolutions of briquette structure and stress. The mechanical behaviour of powders was characterised by the density independent Drucker-Prager Cap (DPC) model. The parameters in the DPC model were determined by conducting experimental die compaction on iron ore fines. The stress distributions inside the briquettes at the maximum compression and ejection stages were analysed. The relative density, Von Mises stress and hydrostatic pressure showed clear declines from the top to the bottom. The effects of powder-wall friction and feeding pressure on briquetting were studied. The average relative density and power draw increased almost linearly with increasing feeding pressure. However, a nonlinear trend was observed with increasing friction. The results suggested that an optimal briquetting process could be achieved by selecting proper boundary conditions.