On-Line Measurement of Moisture Content of Iron Ore Slurries

Abstract

This report presents a method of measuring moisture content in iron ore slurries using the application of microwave. The composition of iron ore slurries consists of magnetite, hematite, calcium carbonate, magnesium carbonate, siderite, alumina, silica, and water. When being placed in an electromagnetic field, interactions will happen between the slurry components and the field. Permittivity ϵ^* is the main parameter to describe these interactions. Since water has the largest dielectric constant compared with other materials, the water content of the material can be estimated from measured permittivity values. For each species, attenuation and microwave phase shift are two intermediate functions related to permittivity, temperature and bed depth when a microwave is passing through particles on conveyor belt. According to theory, a linear model is expected between the materials’ moisture content and the ratio of attenuation and phase shift.