Abstract
It is noted that the traditional (standard) method of testing ore materials, due to its high labor intensity and low representativeness, cannot serve as the basis for controlling the quality of ores during their extraction and processing. The proposed spectrometric modification of the gamma-albedo method allows eliminating labor-intensive operations of ore grinding, preparing analytical samples (~0.1 mm) and direct chemical analysis for iron. Studies of the spectral distribution of scattered gamma radiation from the Se-75 radioisotope source (~220 keV) on ores with different iron content revealed critical energies and zones of their displacement depending on the ore quality and the energy of scattered gamma radiation. The critical energies found in the spectral distribution of gamma radiation albedo allowed selecting the optimal energy intervals in the hard (above the critical energy) and soft (below the critical energy) regions of the spectrum from the point of view of the maximum contrast of the ratio Ψ value of the scattered gamma radiation intensities measured in the selected energy intervals, with changing the iron concentration. In the course of testing the proposed modification of the method of monitoring the iron content in partially prepared samples weighing ~ 60 kg, with the size of 40 mm, there was achieved the mean square error of 1.32% abs. Reliability of the achieved accuracy is confirmed by the comparative value of the relative mean square deviation of the ratio Ψ value of intensities calculated on the basis of multiple measurements of a partially prepared sample.