Design and Fabrication of Optimized Magnetic Roller For Permanent Roll Magnetic Separator For The Processing of Low Grade Iron Ore

Abstract

The quality of iron ore in terms of high iron content is a critical parameter in iron and steel- making processes. So, it is necessary to take step towards the utilization of low grade iron ores, since, the higher-grade ores (non-renewable natural resource) become depleted. Whereas, the economics of low grade iron ore requires a process that can perform beneficiation at a low price and environmentally friendly way. Also, the effective utilization of these low grade iron ores depends upon the selection of suitable processing techniques which in turn mainly relies on the ore’s compositional features. Therefore, in the present work, the prior characterization studies on as-received ore sample followed by the design of Permanent Roll Magnetic Separator (PRMS) through Finite Element Method Magnetics (FEMM) analysis of magnetic roller (the active part of PRMS) was carried out. The FEMM analysis indicates that the optimized magnetic roller having a magnet-to-steel disk thickness ratio of 5 mm: 2.5 mm was proved to be gainful in beneficiating low grade hematite ore due to the efficient magnetic field value from the roller surface that is, 0.89 to 2.59 T. The obtained FEMM data was validated through prediction analysis using the Artificial Neural Network (ANN) modelling technique. Further, the design calculations of newly developed lab-scale PRMS in terms of power requirements and belt tensions were addressed. In addition, the optimization of operating parameters of newly designed lab-scale PRMS has an impact on achieving the best performance in mineral processing, cost- effectively. So, the effect of feed rate (ton/h), roller speed (rpm), and belt thickness (mm) of PRMS on the processing of low grade hematite ore through the Design of Experiments (DOE) approach was addressed. The parametric optimization was carried out using Taguchi-based L27 orthogonal array design. The significance of the parameters on the overall quality of the product was evaluated quantitatively by the Analysis of Variance (ANOVA) method. It was found that the belt thickness was the most influential factor on the product of desired Fe grade and recovery %. The obtained regression coefficient (i.e., R2 = 87.13 and 91.69 % for Fe grade and Fe recovery %, respectively) and normal probability plot show the highest correlation between the experimented and predicted data. iii Also, the characterization study on optimized separated products endorse the enrichment of Fe content in magnetic products as compared to middling and non-magnetics. The obtained results suggest that the FEMM analysis is more suitable for designing of optimized magnetic roller for processing low grade iron ore. Moreover, the overall agenda of the present work was to find a positive solution towards the processing of low grade iron ore with reasonable expenditure.