Determination of the Magnetic Material Composition in Ultra-low-grade Magnetite by ICP-OES and Washability Evaluation

Ultra-low-grade magnetite could be used after magnetic separation, resulting in magnetic material being the major product. The content of useful and harmful components in magnetic materials are ideal for the washability evaluation of ultra-low-grade magnetite. However, they have received little attention so far. In this study, electromagnetic separation and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) were used to determine the contents of useful and harmful compositions (TFe, V₂O₅, TiO₂, P, Cu, Pb, Zn) in raw ore and magnetic material. When the component (V₂O₅, Cu, Pb, Zn) contents were far lower than the required contents of criterion, the contents of these elements after magnetic separation varied but did not affect the smelt and evaluation results. However, the contents of TFe, TiO₂, and P changed obviously after magnetic separation. The TFe content increased from 14.23%-16.60% to 53.95%-69.86%, whereas the TiO₂ content decreased from 4.43%-5.02% to 0.84%-1.83%. The P content decreased from 0.11%-0.30% to 0.027%-0.048%, which affected the smelt and evaluation results (in Table 2). The concentrations of TFe, TiO₂, and P can be used to reflect the smelt selection of ultra-low-grade magnetite. The concentrate is easily obtained by low intensity magnetic separation and the content of TFe, P, Cu, Pb, Zn meets requirements. Attention should be paid to the evaluation of TiO₂ in tailings since most TiO₂ is concentrated in the tailings. In conclusion, this is a feasible method to evaluate the washability and define the objective elements of utilization by using electromagnetic separation and ICP-OES. This method can not only evaluate the smelt possibility of ultra-low-grade magnetite but can also determine the elements to be used, making it meaningful to the comprehensive utilization of ultra-low-grade magnetite.