Iron ore grindability improvement by microwave pre-treatment

The influence of microwave pre-treatment on grindability of iron ore (Orissa, India) was investigated by grindability tests. SEM analysis characterized the micro-fractures in microwave treated sample. This may be due to the thermal stress cracking resulted from microwave energy pre-treatment. XRD analysis showed the crystalline content of the sample. It was found that the microwave treated iron ore has peak more than that of untreated ore, i.e. the crystallinity increased with the microwave exposure time. The calculation of HGGI indicated increase in the ease of grinding or decrease in grindability index of the microwave treated ore. Grindability test showed that the microwave treated iron ore grinds much more rapidly initially than the untreated ore. The results showed that the breakage function of both microwave untreated and treated iron ore is dependent of the particle size. The grindability increased significantly as a result of microwave pre-treatment with the specific rate of breakage (Si) increasing by an average of 50%. It was concluded that microwave assisted grinding produced good results particularly for grinding characteristics.