Grinding size estimation and beneficiation studies based on simple properties of ore components

In this study, the physical and mineralogical properties of three chromite ores taken from three different locations of Turkey (ore A, B, and C) were determined before the lab scale concentration studies. In this context, the mineralogical determination of mineral structure, liberation degree of valuable/gangue minerals, grindability properties (Bond work index, BWI), and size distributions of each ore were determined in detail. An empirical equation was derived based on the liberation size of Cr₂O₃, and the F₈₀ and P₈₀ values (80% passing size of feed and product in grinding, respectively) of the sample were obtained from the BWI tests for each ore. An estimation approach for the primary grinding size with the help of this equation was realized for each ore in the laboratory scale experiments. The results of first series of enrichment test for ore A showed that the chromite content of the concentrate (45% Cr₂O₃) was slightly lower depending on insufficient liberation size compared to ore B and ore C. On the other hand, due to the insufficient liberation in coarse size fractions, the middling with relatively high Cr₂O₃ content were obtained for ores B and C. After the optimization of the test conditions, saleable concentrates having 49-51% Cr₂O₃ grades with suitable chromite recoveries could be obtained for each type of ores. The empirical formula proposed in this research provided very suitable results (concentrates having saleable grades and higher metal recoveries) for the selection of primary grinding size of the ores. However, the results of the equation were limited to the ores used in these experimental studies. Therefore, it is recommended that the validity of this equation should be tested for other types of ores.