SU939086A1 - Lumpy materials separation method - Google Patents

Description

(54) METHOD OF LAP MATERIAL SEPARATION

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The invention relates to methods for enriching lump materials based on the measurement of gamma radiation from a radiation source, scattered forward with a piece of coal or rock, and the gamma radiation of naturally radioactive elements contained predominantly in the rock, and can be used in coal mining to automate the rock sample.

A known method of separating bulk materials, which uses the effect of unequal attenuation of penetrating and scattered radiation by pieces of coal and rock. The source material of the conveyor is fed to the measurement zone, where the sources of pronounced and reflected gammoluchs are installed. Penetrating and scattered rays fall on the detector, which gives a signal to the electronic unit, which sends a command to the actuator 1.

The disadvantage of this method is the weak elimination of the influence of the geometrical sizes of the sorted pieces, which leads to a decrease in the separation efficiency.

In the known method, the radiation from the sources of penetrating and reflected radiation must be collimated to the minimum size of the pieces to be sorted, otherwise the detector will receive direct radiation from the source of penetrating radiation and radiation reflected from the structures from the source of reflected radiation. This will lead to a significant increase in the background radiation, at which it is impossible to exclude the influence of the geometric dimensions of the pieces. However, at low collimation angle, the intensity of both reflected and penetrating radiation will be significantly affected by the relief of the sorted pieces, which also leads to a worsening of the size effect and ultimately to a decrease in the separation efficiency.

The closest to the proposed technical essence and the achieved result is a method for the separation of coal, including measuring the density of gamma radiation of naturally radioactive elements with subsequent separation of the material 2.

The disadvantage of this method is low separation efficiency.

The purpose of the invention is to increase the separation efficiency by eliminating the influence of the sizes of the pieces.

This goal is achieved due to the fact that the material is additionally irradiated with gamma radiation from the source, the density of the radiation flux scattered in the forward direction is measured, and the signals are recorded sequentially from an additional radiation source and from naturally radioactive elements.

As a separating attribute in measurements of the accepted value of the ash content of pieces of coal and rock, since these values differ by more than an order of magnitude. The sensitivity to ash content (relative change in detector counting rate when ash content changes by 1 abs.%) When scattering radiation in the forward direction is negative and is 1.0% (when determining ash content from natural radioactivity, the sensitivity is positive and is 3.0%) . The sensitivity to the size of the piece in both cases is negative and approximately 2 times higher with forward scattering, and the sensitivity to the size of the piece in this case exceeds the sensitivity to ash content by approximately 5 times. Therefore, the amount of ash content, determined by the sum of counting rates for forward scattering n and by the natural radioactivity nj, is summed with coefficients of different sign and magnitude, which are obtained during calibration. Moreover, if the ash content has not changed, but the size of the piece has increased, n.i is sharply reduced, and P2 decreases slightly, but the coefficients obtained during the calibration are such that the algebraic sum does not change. With an increase in the ash content of the piece and other conditions being equal, the value of P2 increases, and the value of P; decreases, resulting in a sharp increase in output.

The drawing shows schematically a device, an implementation method.

The device includes a conveyor 1, a radiation source 2, a scintillation detector 3, a screen 4, an electronic computing unit 5, an actuator 6 actuator 6, an actuator 7, a coal receiving bin 8 and a rock receiving bin 9. Before starting work, the device is calibrated. Pieces of material with average and limiting sizes and known ash content are fed to the conveyor. The values of n are determined, and the Ps- method of least squares is used to obtain a calibration ratio.

Ao-b, p, + bspg,

where hell, b, and bz are the calibration coefficients.

The method is as follows.

In the device that implements this method, the source material by the conveyor 1 is fed to the irradiation zone of the source 2, the forward scattered radiation is sent to the detector 3, which outputs a signal to the electronic computing unit 5. In the block

the signal is memorized with the calibration coefficient bi. Moving on the conveyor, a piece of material enters the detector's field of view on a piece of material and the gamma-radiation of the naturally radioactive elements contained in the piece is measured. The signal is also fed to the electronic computing unit, where it is subtracted from the previous value with the calibration coefficient bj.

In an electronic computing unit, a piece of coal or rock is determined. If the piece is assigned to a rock, the electronic computing unit issues a control signal to the actuator actuator 6, which directs the piece

into the rock receiving hopper 9. If the piece is assigned to coal, the actuator 7 remains in its original state and the piece falls into the coal 8 receiving hopper.

Application of the lump separation method

materials allows to increase the separation efficiency.

Claims (2)

1. USSR author's certificate number 169458, cl. On 03/13/06, 1963. 2. USSR author's certificate No. 547165, cl. 03/13/06, 1974 (prototype). "Ea