An attempt to apply traceability to grinding circuits

LKAB has recently started start the new pelletization plant at Malmberget (MK3). The raw material is a mix from Kiruna and Malmberget. This means there will be different ores having different Fe-content and levels of contaminants. That is why the traceability of the process should be one of the crucial factors for future development of different product(s). Traceability generally means the ability of a system to indicate the current or historical state of activities. The new pelletising plant necessitated an investment in a new grinding section in the concentrator. The difference, compared to the old section, is that the mills in section 6 are larger and have a higher capacity and in section 5 the coarse material is fed to a wet magnetic cobbing separator before the primary mill. The particle size analysis from the section 5 gives similar results compared with the results of section 6. There are slight variations in the results; the older mills in this section produce a steeper final particle size distribution. It is, however, to early to say if this is linked to mill size, or if it is the result of a better, worn in, graded charge. The Particle Texture Analysis gives a good overview how magnetite is liberated at every fraction and which minerals are associated to the magnetite.