Study on Characterization and Identification of Mill Scale
Total iron and other impure elements such as silicon, phosphorus, calcium, magnesium, titanium, arsenic and lead are measured by X-ray fluorescence (XRF) spectrometry, which the analytical sample is prepared by the way of glass fuse piece. And the total iron content is achieved by calculation of the XRF results. Calibration curve of XRF is set up by iron ore certified reference materials and other relative certified reference materials according to the characteristics of mill scale. The standard deviation of the method is better than ISO9516-1. Carbon and sulphur are determined by Infrared Spectrometry. The ferrous content is achieved by redox titration. X-ray diffraction is applied in phase analysis of mill scale and natural iron ores. Mill scale has the following characteristics which are significantly different from iron ore. It is of sheet layered structure, one side of which is densely metallic luster and the other loosely porous. The loss of ignition is from negative 6.16 to negative 6.48. The ratio of total iron to ferrous is from 1.50-1.70. The mineral phases are wustite, magnetite and hematite. The Manganese, copper and zinc are relatively higher in it than iron ores. All above could be used to distinguish mill scale with natural iron ores. The results of chemical analysis are favorable based on the accuracy and precision and the method of identification of mill scale is feasible, which contributes to the reuse of mill scale.