Nuclear method of density and moisture measurement of pre-sinter ore mix

Frequently sintered ore is used for production of pig-iron in a blast furnace. In the sintering process the pre-sinter mix (PSM) consisting of fine iron ore, coke and limestone is moistend. When put into rotating drums it takes the forms of clods. The size of clods depends on moisture content of the mix. Granulation is fixed then by the ignition of coke contained in the mixture. Measurements executed in the laboratory showed that the volume density is high for dry pre-sinter mixture, then falls to a minimum at 6-7% moisture (by weight) and rises again to values corresponding to dry mix at 11-12% moisture. Density is influencing the moisture values as measured using the neutron thermalization gauge. Therefore it is necessary to measure both density and moisture of the pre-sinter mix in order to obtain precision values of PSM humidity. Density is measured using γ-ray backscattering and used as input to the correlation function which changes the moisture content. Gamma-rays from the isotopic 137Cs source is used. Error analysis carried out showed that the precision obtainable with such procedure is lower than 0.5 volume per cent of humidity. (author). 7 refs, 29 figs, 3 tabs