NOVEL APPROACH TO OPTIMIZE GRINDING CIRCUITS- MODELLING STRATEGY TO MONITOR BALL MILL PARTICLE SIZE DISTRIBUTION DATA AT LAKAN PLANT

Online monitoring and control of size distribution in any grinding circuit is a vital task in mineral processing plants. Flotation process efficiency depends on the size of feed materials and also fraction of the fine particles e.g. -38 microns. This paper presents a new approach to monitor the size distribution of Lakan Pb/Zn flotation circuit in Iran. A software monitoring size distribution has been developed, based on two main parameters named n which is reduction ratio in the mill and b which comes from Guadin equation, i.e.W = aD^b . n depends on mill characters and feed function while b depends on ore, instruments, and other properties. Liberation and size fraction studies showed that the d80 of ground material should be -74 microns and weight of passing 38 microns materials should be 35-40%, which is the optimum condition for the flotation recovery. Finally, results obtained from ball mill circuit for n and b indicated that these parameters were equal to nBall Mill=80-87 and bBall Mill=0.84-1.1 at optimum condition. Under this condition, flotation recovery increases up to 75%, which is practically confirmed in Lakan flotation plant.