Method of determining ash content in coal by combined gamma ray transmission and scattering measurements

摘要

According to the invention continuous measurement of ash content in coal transported on belt conveyors, in particular with belts comprising steel lines is possible. The invention comprises the step of directing gamma radiation from above towards the stream of coal transported on the belt conveyor, preferably at an angle of 45°, and registering the amount of impulses in the beam transmitted through the coal and the conveyor belt, at the same time in two measurement geometries: absorption geometry of radiation, in which the detector ( 4 ) is located in the axis of the primary radiation beam, and scattering geometry of radiation, in which detector ( 5 ) is located in the axis perpendicular to the primary radiation beam. The energy of the radiation source ( 3 ), preferably chosen from the range of 30 - 70 keV, is such that the absorption mass factors of this radiation for the coal matter and for the mineral part are significantly diversified.