The effect of magnetic mineral grain size on magnetic susceptibility and MDF of iron sand from Senggigi beach, West Lombok, West Nusa Tenggara province of Indonesia

This study aims to determine the effect of grain size on magnetic susceptibility and median destructive field. The samples were iron sand taken from Senggigi beach, West Lombok. Samples were prepared in extract and non-extract. The extracted samples were then subjected to grinding for 1,2, 3, and 4 hours. Both extracted and non-extracted samples were tested using X-ray Fluoroscene (XRF) to determine the chemical element. The extracted sample was tested using a scanning electron microscope (SEM) to detect magnetic mineral morphology. All samples were characterized using magnetic susceptibility and magnetic remanent stability by MDF analysis. Based on data analysis, the composition of iron sand is dominated by Fe, about 76.61% before extracting and 78.60% after extracting. The magnetic susceptibility of iron sand ranges from 4.896 x 10−4 m3 I kg to 6.333 x 10−4 m3 I kg. Magnetic remanent stability is indicated by an increase in MDF means that the magnetic mineral is dominated by Multi-Domain (MD). The grain size of the magnetic mineral decreases following the time of grinding. These results are supported by the SEM image. Based on the data, it can be concluded that if the magnetic mineral grain size is greater when the magnetic susceptibility decreases.