Microwave aquametry according to ASTM D4643-17 for moisture determination in iron ore tailings.

Abstract

The gradual increase in the exploitation of iron ore leads to a need for the disposal of tailings from its processing. One of the key features of a granular system stacked is its moisture content. This work aimed at evaluating the use of microwave oven to determine the moisture content (following the ASTM D4643-17 standard) of iron ore dewatered tailings, for fast assessment of the geotechnical condition of every stacked layer on disposal areas. The preconized method has showed good agreement with the conventional oven method (standard assay), resulting in linear equation with coefficient of determination of 0.9953. However, the recommended method has shown less accuracy in the range of low moisture values (below 5 %), which does not represent a critical disadvantage from the point of view of geotechnical safety. The economic impact of the method advocated here will be great, since the movement of large volumes of tailings in limited areas leads to customary downtime, often resulting from waiting for confirmatory analytical results to practice within the safety limits.