Perpustakaan Digital ITB

We have studied the magnetic characteristics of clays in relation with burning process. The study involved field samples in the form of clinkers from Tan Jung Redep in East Kalimantan and a number of laboratory samples made of clays takes from rice frelcZ top soils, and sediment in caves. The methods used in this study were measurement of magnetic susceptibility, measurement of ARM (anhysteretic remanent magnetization), and measurement of IRM ( isothermal remanent magnetization). The measurement of magnetic susceptibility showed that the intensity of magnetic susceptibility in clinkers varies with grain size and coloration, which indicate the length and intensity of burning. Simulation of burning process with laboratory samples show than burning at temperature of less than 500° increases the susceptibility, while that at higher than 500 °decreases the susceptibility. Meanwhile, the ARM intensity decay curves obtained before and after burning at 500 ° show no change. This is very different with burning at 800 ° The intensity decay curves obtained before and after burning show significant change indicating a for•n;ation of new magnetic mineral. In this process, it is suspected that some of magnetite (Fe3O4) were oxidized and transformed into hematite (Fe2O,). Nevertheless, magnetite still dominates the magnetic minerals. Measurement of IRM on samples that have been burned at 400 e 7000, dan 800 ° still indicate magnetite as the dominant magnetic mineral. This is supported by the results of XRI) (X-ray diffraction) analysis.