RU2715374C1 - Radiographic separator of minerals - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention relates to devices for separation of crushed mineral material and can be used for X-ray separation of diamond-containing rock of different size classes. Separator comprises conveyor (1), on belt (2) of which receives flow (3) of diamond-containing material (4), X-ray tubes (5 and 6), detector lines from (1…2N) X-sensitive multi-pixel matrices (7 and 8), synchronization device (9), computer processing means (10), which includes ADC array (1…2N) (11), processor (12), RAM (13), in which digital radiation intensity values received from (10), and ROM (14) with programs for controlling operation of separator, determining characteristics of particles of material flow and storing predetermined values of characteristics of enriched minerals, and auxiliary parameters, input / output device (15), means of deviating trajectory of material (16) located above the free fall of material (17), from which particles of enriched mineral fall into accumulator bin (18), and tail products – into storage bin (19). Computer processing means (10) is equipped with functional modules: a module of virtual spatially-connected copies of detector lines, in each virtual pixel matrix of which simultaneously receives digital value of radiation intensity signal, module for determining, for each pair of pixels, the characteristic of the particle of initial material in form of a point in a two-coordinate system, coordinates of which correspond to digital values of signals of radiation intensities in two different energy ranges, which have passed through one and the same section of the particle, normalized to the maximum possible value in the corresponding energy range, a segmentation module for selecting the associated pixel areas and determining the degree of coincidence of the selected pixel area with the minerals characteristic value region, module for identification and development of command for separation of particles of enriched mineral from flow of initial material at compliance of degree of coincidence with criterion of assignment of particle to enriched material. Control output of the identification module is connected to the corresponding input of the separation unit for directing particles separated from the stream into an accumulator bin.

EFFECT: high selectivity of separation of diamond-containing material while maintaining high percentage of extraction of diamonds and high efficiency.

3 cl, 5 dwg, 2 tbl

Description

Technical field

The invention relates to the field of mineral processing, and in particular to devices for separating crushed mineral material into enriched and tail products, in which the separation is based on differences in the degree of absorption of x-ray radiation by various minerals

The proposed device can be used for x-ray separation of minerals, in particular, diamond-bearing rocks of various particle sizes.

State of the art

Known material separators contain the following common functional blocks:

a) a block for transporting particles of the starting material, intended to organize, as a rule, a monolayer flow of the starting material of a certain width through the detection zone to the separation zone;

b) the block of the source of electromagnetic radiation for irradiation of a part of the flow of the source material;

c) a unit for detecting radiation transmitted through the source material, forming a detection zone;

g) block analog-to-digital conversion (ADC) signals of the detection unit;

d) a control and signal processing unit received from the detection unit;

e) a unit for separating the target material from the stream of separated material;

g) the block receiving devices for the separate collection of the target material and the rest.

Known, for example, a separator for separating polymeric materials from municipal solid waste, using the absorption / transmission characteristics of electromagnetic radiation to separate materials of different chemical composition with a capacity that allows its use on an industrial scale [US Patent No. 5339962]. In the described separator, the block for transporting particles of the source material is multi-channel and is made in the form of a conveyor (conveyor) and an accelerating tray mounted on the exit of the particles of the source material from the conveyor. An X-ray tube with a linear focus can be used in the block of the source of electromagnetic radiation, the radiation energy of which is sufficient to measure it in the detection block after passing through the particles of material. The detection unit for radiation transmitted through the material is made in the form of a plurality of detectors, each of which corresponds to one of the registration channels. The detectors are selected in such a way as to provide optimal sensitivity to the used radiation wavelengths of the source. The radiation source located above the output edge of the accelerating tray, and the detectors located on the opposite side of the output edge of the tray, determine the detection zone. A device for processing signals from detection units consists of two sections: a processing unit for analog signals of detectors and a processing unit for digital arrays of detector signals. The detector analog signal processing unit includes standard amplifiers, analog type sampling and storage devices controlled by a microcontroller, and an analog multiplexer controlled by a microcontroller, which provides a serial connection of the signals of each detector to an analog-to-digital converter. The processing unit for digital arrays of detector signals includes a microcontroller, ROM for storing system parameters, ROM for storing a program that controls the microcontroller, RAM for storing digitized data received from the detectors for the time required for the processor to perform operations specified by the control program algorithm. The unit for separating the target material from the source material stream is located behind the output edge of the accelerating tray in the direction of flow and is made in the form of many air pressure ejectors, the number of which, as a rule, corresponds to the number of radiation detectors (channels). The separation unit is connected with the corresponding outputs of the processor, designed for independent control of the air pressure ejectors of the respective channels of the transportation of the source material through the output section, with ejector drivers located in it, the number of which also corresponds to the number of channels. The receiver unit is made in the form of two conveyors arranged in parallel and separated by a partition for separate acceptance of the target material and the rest.

For the separation of polymeric materials in this separator, the normalized value of the transmitted / absorbed electromagnetic radiation intensity values recorded by the detectors, the energy of which is selected based on the absorption properties of the material of the sorted objects, was selected as a separation characteristic. The value of the separation characteristic obtained in this way using the processor is compared with a predetermined threshold value and the mass flow of the sorted objects is divided into the target polymer material and the rest according to the result of the comparison.

The main disadvantages of such a separator that sorts well, for example, PVC waste from polyester, but limiting its use for other types of materials, in particular for the separation of diamond-containing mineral raw materials, are obvious:

- Poor selectivity (accuracy) of the separation of materials, since the “threshold” separation method used does not sufficiently take into account the effect of the thickness of the material on the measured radiation intensities;

- Low productivity of the separator for processing materials of small classes of fineness, because the increase in the number of detectors necessary for their detection will lead to a long-term conversion and processing of signals by the processing unit of the analog signals of the detectors.

Known separator for the enrichment of various mineral rocks and, in particular, for the separation of diamond-containing rocks [RF Patent No. 2470714]. In this separator, the block for transporting particles of the source material is made in the form of a conveyor (conveyor) to create a monolayer stream of particles of the source material. The block of the source of electromagnetic radiation is made in the form of two monoenergetic sources of x-ray radiation, the energies of which are not equal to each other, for example, x-ray tubes, each of which is equipped with means for forming a narrow beam of radiation, sequentially located in the direction of the flow of particles of the source material above its surface. The detection unit for radiation transmitted through particles is made in the form of two linear X-ray sensitive detectors sequentially located in the direction of motion of the stream of particles of the source material under its surface. Each detector is located in such a way that provides registration of the intensity of the radiation transmitted through the particles of the source material only from the corresponding radiation source. In this case, the detectors are designed in such a way that the maximum spectral sensitivity of each of the detectors corresponds to only one of the two energy ranges and ensures that the radiation of the corresponding source transmitted through the particles of the source material is recorded in only one energy range. The radiation sources and their corresponding detectors form a two-channel detection zone, in which each channel has its own source – detector pair. The signal processing unit is based on a computer tool, including a module for calculating the separation characteristics of each particle of the source material in the stream and a module for comparing the obtained values of the separation characteristics with a given value of the separation characteristics for the mineral being enriched - diamond, for the operation of which a special computer program is provided in the corresponding a computer means module and providing a connection between the processing device and the separation unit when Making a predetermined comparison conditions. The separation unit is made in the form of a reset mechanism to change the trajectory of the particles of the enriched mineral - diamond and direct them to the receiver unit, made in the form of a drive.

As a characteristic of R separation in this separator, the ratio of the attenuation coefficients of a particle of the x-ray radiation material of two selected energy ranges is selected, the value of which is calculated based on the measurements obtained by the formula (1)

R = μk (E1) / μk (E2) = ln [I1 (E1) / I2 (E1)] / ln [I1 (E2) / I2 (E2)], where

μk (E1) is the attenuation coefficient of an X-ray material with an energy E1 by a particle of material;

μk (E2) is the attenuation coefficient of a particle of X-ray material with energy E2;

I1 (E1) - the intensity of x-ray radiation from the first radiation source, which passed only through the conveyor belt;

I2 (E1) - the intensity of x-ray radiation from the first source passing through the tape and a particle of material;

I1 (E2) - the intensity of the x-ray radiation from the second radiation source, which passed only through the conveyor belt;

I2 (E2) - the intensity of x-ray radiation from the second radiation source that passed through the tape and a particle of material.

If the obtained numerical value of the separation characteristic R of the particle coincides with the specified numerical value of the separation characteristic R for diamond, the sorting unit changes the path of this particle so that it gets into the drive.

The described document proposed a technical solution to the problem of increasing the extraction of the enriched mineral - diamond, regardless of the range of thicknesses of individual particles of the starting material in the technological class size.

The authors of the proposed technical solution also note the importance of irradiating the rock with monoenergetic radiation beams, while the choice of the energy of the radiation sources E1 and E2 is crucial to ensure maximum diamond recovery.

However, the practical verification of the proposed technical solution on real diamond-containing material of class +3 - 6 mm, carried out by the authors of the present invention, although it showed a rather high extraction of the enriched mineral - diamond, but revealed its low selectivity: a large number of false cut-offs on the diamond. Along with real diamonds, a large number of flat particles (plates) of accompanying minerals up to 6 mm in size, 0.5-1 mm thick, were present in the real source material. The low selectivity of the proposed technical solution, apparently, is a consequence of both the insufficiently monochromatic nature of the spectra of x-ray sources and the non-optimal choice of the energy ranges used.

и

.Thus, the solution proposed in the described document using the dual-energy scheme, unfortunately, does not completely solve all the practical problems of the separation of diamonds in the material. This is because the characteristic R in expression (1) is calculated for specific energies, while the radiation spectrum of real x-ray tubes is not monochromatic (the x-ray radiation of each tube corresponds to the range

and

.

A known separator for separating materials, also using the characteristics of the absorption / transmission of electromagnetic radiation, is intended mainly for sorting particles of various polymer resins for subsequent processing [US Patent No. 9566615]. In this separator, the source particle transport unit is made in the form of a conveyor. In the block of the source of electromagnetic radiation, an X-ray tube with a linear focus can be used, preferably braking energy, the radiation of which contains two different energy ranges. The detection unit for radiation transmitted through particles contains a linear detector, consisting of rulers, which are a set of many pixels and provide optimal sensitivity to only one of the selected energy ranges of the radiation of the x-ray tube. The radiation source unit and the detection unit, the length of which corresponds to the width of the conveyor belt, are located opposite each other in the area of free fall of the particles of the source material after the conveyor in such a way that the path of the particles is between them and determine the detection zone. The signal processing device of the detecting unit includes: a unit for obtaining digital values of IL and IH signals, respectively, the intensity of low-energy radiation transmitted through the particle of the source material, and the intensity of high-energy radiation transmitted through the same particle of the source material, connected to the outputs of the respective detector lines through the ADC , a unit for storing and setting system parameters, such as a threshold value of the ILp signal, a threshold value of the separation characteristic Sp, a differential parameter k; a first determining unit for comparing the values of the IL signals from the block for obtaining the digital values of the IL and IH signals with the threshold value of the ILp signal from the setting unit; a calculation unit for obtaining a current value of the partition characteristic S; a second determination unit for comparing the current value S from the calculation unit with its predetermined threshold value Sp from the installation unit; the output section, the inputs of which are connected to the corresponding outputs of the first and second determination units, and the output - to the input of the sorting unit. The unit for separating particles of the target material from the feed stream is located behind the detection zone in the direction of movement of the particle stream and can be made in the form of many ejectors of air pressure. The block receiving devices can be made in the form of bunkers for separate acceptance of particles of the target material and other particles.

The threshold value of the ILp signal is set to a value lower than the intensity of the transmitted x-ray radiation IL for all particles of the material of the given fractions. The intensities IL of the transmitted x-ray radiation are measured in advance for a group of predetermined fractions of particles of sortable resins having the maximum possible thickness. The first stage of “threshold” separation consists in comparing IL signals with a threshold ILp value in the first determination unit and provides for the determination of particles of the starting material that are not exactly related to the given fractions, but does not allow to precisely determine the particles of the given fractions due to the influence of the particle thickness on the IL signal intensity .

Parameter S is selected as a separation characteristic for separating particles of materials that can be assigned to predetermined fractions. The current value of the parameter S is calculated in the calculation unit for each pixel in the corresponding detector line according to the formula (2):

S = loge (IL / I0) -k⋅loge (IH / I0) = - (μL-k⋅μH) t, where

IL is the intensity of the transmitted x-ray radiation of low energy relative to the measured object;

IH is the intensity of the transmitted x-ray radiation of high energy in relation to the measured object;

I0 is the intensity of the x-ray radiation of the source;

μL is the attenuation coefficient for low-energy x-rays;

μH is the attenuation coefficient for high-energy x-ray radiation;

t is the thickness of the measured object;

k is a differential parameter, which is an arbitrary constant.

To identify particles of given fractions, the value of the parameter k is set such that the value of the separation parameter S = 0.

It should be noted that to increase the accuracy (selectivity) of separation, 4 blocks can be additionally included in the signal processing device of the detection unit for periodically adjusting the threshold values ILp, Sp and differential parameter k according to the results of previous measurements.

The disadvantages of this separator, limiting the effectiveness of its use for other types of materials, in particular for the separation of diamond-containing mineral raw materials:

- Complicating the design of the detection unit due to the availability of additional electronic computing devices for two-stage separation of materials, especially in the case of operations to adjust the system parameters ILp, Sp and k, and, accordingly, increasing the duration of signal processing;

- The difficulty of adjusting the threshold adaptation scheme, caused by the need to apply operations to adjust system parameters depending on the characteristics of the accompanying material;

- Unwarranted efficiency on small, for example, diamond-containing material, due to the long period of collection of statistical data necessary to adjust system parameters.

Also known is the accepted for the prototype separator for separating materials, intended mainly for sorting small metal particles, such as screws and nuts, and using the absorption / transmission characteristics of electromagnetic radiation [RF Patent No. 2344885]. The proposed technical solution is aimed at solving the problem of creating a safe, economical device for reliable detection of small particles, mainly metal, ensuring their reliable separation from the rest of the bulk (source) material due to the positioning of the blowing nozzles immediately after the observation site. In this separator, the source particle transport unit is made in the form of a conveyor. An X-ray tube may be used in the block of the source of electromagnetic radiation, preferably braking energy, the radiation of which contains two different energy ranges. The detection unit for radiation transmitted through particles contains at least two detector arrays formed by linear multi-pixel photodiode arrays. The filtering devices installed in front of the respective detector arrays, designed to transmit X-ray radiation with different energy spectra, provide in each line optimal sensitivity to only one of the selected energy ranges of the X-ray tube radiation. A detecting unit, the length of which corresponds to the width of the conveyor belt, may contain, for example, ten detector lines located across the conveyor belt. The radiation source unit and the detection unit, located opposite each other on different sides relative to the conveyor belt, determine the detection zone. The analog outputs of the detector lines of the corresponding energy ranges are connected to the inputs of the corresponding ADCs to convert the intensity signal into digital form with a 14-bit dynamic range. The signal processing device of the detection unit includes FIFO-type memory devices for recording the digital form of the intensity signals of the detector lines of the respective radiation energy ranges and serial interfaces, the output of which is connected to the multiplexer input for converting the signals into a serial stream of data bytes. The output of the multiplexer via a standard serial interface is connected to a computer evaluation tool for determining the characteristics of each of the particles of the source material based on the analysis of two x-ray images recorded by the detection unit. After hardware demultiplexing of a sequential stream of data bytes into two channels for processing signals of high and low energy intensity and correcting black / white levels for each element of the decomposition of detector lines separately, a computer tool for evaluating implements an algorithm for processing information from recording means, which includes noise suppression in the signal provided independently for the data of each energy channel by a procedure similar to smoothing averaging filter of several rows from expressions is temporarily stored in the buffer memory. Further, the data is processed in parallel as follows:

a) determines the average transmission of the analyzed particles to obtain the average resulting transmission in the corresponding energy range of the spectrum,

b) the atomic density class of the analyzed particle is determined from the intensities of two image channels in different spectra based on n-classes of averaged atomic density, by the number of decomposition elements of the detector lines, which are weakly dependent on the transmission of x-ray radiation and, accordingly, on the particle thickness. In the presence of a priori known average atomic densities of typical materials in the product to be sorted, it becomes possible to classify various particles of the separated product as one or another type of material. And when calibrating the proposed separator according to the samples of typical materials in the sorted products, the hardware-dependent problems of sorting quality are also minimized.

Then, based on the averaged transmission and atomic density class, characteristic classes are formed to assign a characteristic class of material to each pixel of the photodiode arrays in which the signal is recorded when particles of the separated material are transmitted. A morphological filter is used to evaluate the particle shape of the separated product based on a priori knowledge of the processed products. The algorithm processes characteristic classes as images and, taking into account morphological filtration data, makes a decision on assigning the analyzed particle of the separated product to one or another known material based on the numerical conformity criterion. A sorting unit for separating particles of predetermined fractions from the feed stream is made in the form of a blowing device with a line of blowing nozzles located on the drop site after the conveyor belt perpendicular to the direction of its movement. The block receiving devices can be made in the form of bunkers for separate acceptance of the target material and other particles.

In the proposed separator, the signal processing device of the detecting unit is designed in such a way as to ensure identification of the separated particles, both by their shape and by the material contained in them, by creating and analyzing their characteristic images.

However, such identification of objects (separated particles) seems redundant in the separation of mineral raw materials, in particular diamond-containing mineral raw materials.

The disadvantages of this separator, limiting the effectiveness of its use:

- Insufficient selectivity (accuracy) of the separation of materials, since the morphological filter used in the separator with the analysis of directly pixel image data will be ineffective for selecting a much larger variety of particles of useful minerals in diamond ores than in the tasks of extracting metal inclusions from materials of household or industrial waste fractions;

- Hardware complexity associated with the presence, on the one hand, of a multiplexer for sequentially reading data from a plurality of rulers, and on the other hand of a demultiplexer that separates the information of low and high energy channels for mathematical processing;

- Limited performance due to sequential reading of data from linear photodiode arrays.

The performance limitation is illustrated by the following relationships. In the general case, the size (width across the tape) of the element of the detector means is determined by the minimum size class of the material, and the transport speed cannot exceed the value of the conveyor belt moving by one “line” (length of the detector line in the direction of movement of the stream of particles of the source material), referred to time reading this "line".

So, for example, when the width of the conveyor belt is 300 mm, the number of detector means is 2, the length of the linear photodiode array is 50 mm (for example, S8865 - Hamamatsu), the read time of each matrix is from 0.4-1.0 ms, the total reading time tc (12 matrices) will be from 4.8 to 12 ms. Assuming the pixels of the matrix with dimensions a × b = 0.4 × 0.6 mm (S8865 - Hamamatsu), we obtain the conveyor speed: v = b / tc, i.e. from about 0.125 to 0.05 m / s, respectively, limited performance.

As a means of overcoming this drawback, the separator offers sectioning - a multiple increase in the width of the conveyor belt with a corresponding increase in the number of detector arrays of reading devices equipped with separate power and synchronization signal generators, which ultimately complicates the device.

Thus, there remains a need to develop an easy-to-perform, productive device that allows the separation of diamond-containing raw materials with high selectivity while maintaining a high recovery percentage.

Disclosure of the invention

The present invention provides a device, namely, an X-ray mineral separator comprising:

a source material transportation unit for organizing a monolayer flow of individual particles,

an X-ray source unit configured to irradiate over the entire width of the portion of this stream perpendicular to the direction of its transportation, and

the detection unit, made in the form of at least two detector arrays formed by linear x-ray sensitive multi-pixel photodiode arrays mounted perpendicular to the direction of transport of the particles of the source material, for separate registration in different energy ranges of the distribution of radiation intensity transmitted through the irradiated portion of the stream of source material, and the source is x-ray radiation and detector lines are located on opposite sides of the flow hour egg starting material,

a block of analog-to-digital converters (ADCs) connected in series with memory devices of the FIFO type,

processing unit, made in the form of computer tools, including integrated system bus,

CPU,

random access memory (RAM) device for collecting and storing digital values of radiation intensity received from the ADC unit,

permanent memory devices (ROM) with programs located therein to control the operation of the separator and determine the characteristics of the particles of the feed stream of the material, as well as to store predetermined characteristics of the minerals being enriched and auxiliary parameters, and

an input / output device for controlling the separation of particles of enriched minerals from the stream of particles of the source material,

moreover, these computer tools are equipped with functional modules that implement the algorithm for assigning particles to an enriched mineral,

a unit for separating particles assigned to the mineral being enriched from the feed stream and

block storage bins for the separate collection of particles of the enriched mineral and tail products, characterized in that

the output of each matrix of the corresponding detector line of the detection unit is connected to the ADC input and a memory device of the FIFO type of the ADC block connected in series, the outputs of which are connected in parallel to the interface of the processing unit, and the synchronization inputs of each matrix of the corresponding detector line are connected to the output of the synchronization device, while the functional modules include:

a module of virtual spatially coupled copies of detector lines for simultaneously entering into each virtual pixel of the virtual detector array matrix a digital value of the radiation intensity signal recorded in the corresponding matrix pixel,

a module for determining, for each pair of pixels in the respective detector lines, the characteristics of the particle of the source material in the form of a point in a two-coordinate system, the coordinates of which correspond to the digital values of the signals of the radiation intensities recorded in each pixel of the detector line in two different energy ranges passing through the same particle section, normalized to the maximum possible value in the corresponding energy range, and its verification of belonging to A region of a characteristic value of the characteristics of minerals enriched in ROM

a segmentation module for extracting related pixel regions, the particle characteristic value of which belongs to the region of characteristic values of the minerals being enriched and determining the degree of coincidence of the selected pixel region with the region of characteristic minerals of the minerals being enriched,

a module for identifying and generating a team for separating particles of an enriched mineral from a stream of source material, according to the degree of coincidence with the criterion for classifying a particle as an enrichable material, the control output of which is connected to the corresponding input of the separation unit to direct particles separated from the stream to the corresponding storage hopper.

The technical result achieved in the present invention is to provide high selectivity for the separation of diamond-containing raw materials while maintaining a high percentage of diamond recovery.

The specified technical result is achieved due to the functional modules contained in the computer means of the processing unit.

In addition, the present invention achieves an increase in productivity by increasing the speed of reading signals from the entire array of sensitive matrices by independent parallel reading of the intensity of the signals from all matrices at the same time without significantly increasing the number of computer processing tools and complications, thereby making the device. The processing unit, at the same time, receives data from sensitive elements (SE) simultaneously at both X-ray energies of the source over the entire width of the conveyor belt and has the ability to quickly switch from analysis of a separate SE to analysis of a particle of material, namely: programmatically group the regions of SE with characteristics, satisfying the sign of a useful mineral and to verify the conformity of these areas with the specified characteristics based on the size class of the processed material and shaping related areas of electricity cops expansion (pixels) of the detector arrays.

In addition, the proposed invention can be implemented in various modifications, namely, with a different arrangement of structural elements, depending on the requirements of the enrichment process. In particular, the block of the x-ray source can be made in the form of two x-ray tubes arranged one after the other in the direction of transporting the particles of the source material, with each x-ray tube configured to irradiate the particle stream in only one of two different energy ranges of radiation and opposite each X-ray tube on the opposite side of the particle stream is one of the two detector lines of the detection unit, which is made with the possibility of register only one corresponding energy range of the distribution of the intensity of radiation passing through the irradiated section of the flow of the source material.

Alternatively, the detector lines of the detection unit may be arranged parallel to each other in the direction of propagation of the irradiating radiation of the X-ray source unit, each of the detectors being configured to record the distribution of the radiation intensity transmitted through the irradiated portion of the source material stream in only one of two selected energy ranges.

Brief Description of the Drawings

In FIG. 1 shows a diagram of the proposed separator.

In FIG. 2 shows diagrams of synchronization signals:

'Ckc' -20; 'Ckr' - 21; 'trig' - 22; 'EOS' - 23, - and the analog output signal 'Video' - 24.

In FIG. Figure 3 gives a graphical representation of the characteristics of the minerals being enriched. The database contains three areas: 25a - “definitely a diamond”, 25b - “probably a diamond” and 26 - “definitely not a diamond”.

In FIG. 4a and 4b, the grouping of the CE region with the characteristics satisfying the attribute of a useful mineral and the correspondence of these regions to the given characteristics in size (size class) and shape are explained.

The implementation of the invention

According to the circuit shown in FIG. 1, the proposed device is an x-ray mineral separator for separating bulk diamond-containing materials contains a conveyor (1), on the tape (2) which receives a stream (3) of diamond-containing material (4) (means for supplying material to the conveyor, for example a vibrating feeder, not shown ), the radiation source is X-ray tubes: 5 (“low” energy E1) and 6 (“high” energy E2), respectively, with high-voltage power sources located above the flow (3) of material (4), detection means in the form of (1 ... 2N) whether x-ray array sensitive arrays (7 and 8) located under the material flow along a line perpendicular to the movement of the material flow, a synchronization device (9), the outputs of which are connected to the synchronization inputs of all linear x-ray matrix arrays (7 and 8), computer processing means (10) , including: an ADC array (1 ... 2N) (11), the inputs of which are connected to the outputs of the corresponding linear X-ray array arrays (7 and 8), a processor (12), RAM (13), into which the digital values of the radiation intensity enter, P received from (10), and ROM (14) with programs for controlling the separator, determining the characteristics of the particles of the material flow and storing predefined characteristics of the minerals being enriched, and auxiliary parameters, output device (15), means for deflecting the material's motion path (16) located above the free fall area of the material (17), from where the enriched mineral particles fall into the storage hopper (18), and tail products into the storage hopper (19).

The proposed separator operates as follows.

Previously, numerical characteristics identifying a useful mineral - diamond, as well as auxiliary parameters are introduced into a computer processing tool (10), in its ROM memory (14). Then the synchronization device (9), generating signals (20 and 21), and the x-ray source with x-ray tubes (5 and 6) are turned on; after it enters the operating mode, the conveyor (1) is turned on and the flow (3) starts of the diamond-containing material-processing class of fineness (4) along the conveyor belt (2) made of a material with low radiation absorption (for example, polyurethane). Feeding is carried out by a monolayer.

The x-ray radiation of the x-ray tubes (5 and 6) passes through the particles of material (4), the conveyor belt (2) and enters the linear x-ray linear array arrays (7 and 8). According to the output signals (20 and 21) of the synchronization device (9) supplied to the same inputs 'CLK' and 'Reset' (Fig. 2) of all matrices, information is cyclically read from the X-ray linear array arrays (7 and 8). The data collection cycle by choosing the period of these signals is selected to be minimal, but sufficient to integrate the photocurrent of the elements of the linear arrays of arrays (7 and 8) to voltage levels that ensure optimal use of the dynamic range of the subsequent analog-to-digital conversion. The signal levels of the sensitive elements of the matrices (7 and 8) are read out sequentially to the common output 'video' 24 for each array array (7 and 8). These outputs are each connected to the input AI1 ... 4 of a separate ADC (11). The number of ADCs (11) corresponds to the number of arrays matrices (7 and 8). At the same time, from each matrix of arrays 7 and 8, two synchronization signals are received to the ADC start input: EOS 23, indicating the beginning of the matrix - the beginning of the cycle (connected to the 'External Trig' input of the specified ADC (11), and 'Trig' 22 - start the conversion signal of an individual sensor element (connected to the input 'CLK' of the specified ADC (11).

The analog signal coming from the output 'video' 24 of each linear array matrix (7 and 8, has a voltage dimension, the value of which reflects the intensity of the radiation reaching the sensor located under a specific piece of processed material. Each cycle of reading a set of linear array arrays 7 and 8 after quantization - conversion, the ADC (11) forms a numerical array characterizing the distribution (in the direction perpendicular to the direction of movement of the material 4) of the radiation intensity transmitted through the flow (3) of material (4) during its stay over the set of linear X-ray array arrays (7 and 8).

During the cycle of accumulation and data collection, the conveyor belt should be mixed no more than by the linear size ("height") of the sensing element in the direction of material flow. For linear matrices S8865-128G, the height of the sensing element is h = 0.6 mm. Having accepted (from experience) the optimal cycle time T = 400 μs, we obtain the maximum speed V of the conveyor belt 2, which provides full coverage of the stream 3 of material 4 over the entire area of the belt 2: V = h / T ≤ 1.5 m / s.

Numeric arrays corresponding to the distribution of the intensity of radiation reaching the sensitive elements of the linear matrix arrays (7 and 8), or otherwise, characterizing the x-ray transparency of pieces of material 4, passed over the arrays of linear matrices (7 and 8) in a particular cycle are accumulated in the form of "lines" in memory computer processing means (10) that receives information from the ADC (11) directly via the system bus of the computer processing means (10) through a backplane, for example PCA-6106-P4 (to simplify the picture, not showing ana). For example, it could be a PCI bus. Via the air-blast board (15), a means (16) for deviating the trajectory of movement (in the form of a set of, for example, 16 pneumatic valves) over a section (17) of free fall of material (4) from the conveyor belt (2) (1) are connected to computer means (10) . The tool (16) is controlled by a computer tool (10) based on the results of processing a sequence of strings containing numerical arrays. Processing takes into account linear dimensions (selected from the minimum size of the material) and the coordinates of the zone where the signal intensity exceeds the transmission level of an empty ribbon, but is less than the threshold separating the diamond from related minerals. In the proposed separator, the width of the conveyor belt (2) can be 200 mm and it is divided (for example) into 16 zones, each of which corresponds to a pneumatic valve forming an air flow deflecting material (4) in this zone, defined by computer means (10) as diamond. The deviation into the storage hopper is carried out in the area (17) of the free fall of the material (4), after it leaves the conveyor belt (2). Separated material is sent to the enrichment mineral storage bin (18), the rest of the material enters the storage bin (19).

The registration of the intensity of radiation transmitted through the material (4) is as follows. The following parameters are preliminarily determined: the range of characteristics of the minerals being enriched, radiation absorption by structural elements (conveyor belt, film (not shown in Fig. 1), covering matrices (7 and 8) from dust, etc., located between the particle and each pixel of the corresponding detector arrays (7 and 8), the maximum possible value of the intensity of x-ray radiation for each recorded energy range, specify the geometric dimensions of the continuous (connected) region of pixels in two coordinate plane in the direction of particle flow and perpendicular to the direction of flow, the criterion for assigning the particle to the mineral being enriched .. The parameters are loaded into the ROM of the processing device (10).

To determine a parameter that takes into account the effect of radiation absorption by structural elements located between the particle and each pixel of the corresponding detector, the values of the intensity of X-ray radiation with energies E1 and E2 transmitted to devices 7 and 8 in the absence of a particle flow of the source material are separately measured.

Set the maximum possible value of I _max (E1) and I _max (E2) of the x-ray intensity for each recorded energy range, which is determined by the dynamic range of the detector.

To determine the range of values, the characteristics of the minerals being enriched comprise a statistically representative set of standards, the elements of which can be particles of an enriched mineral of various sizes and thicknesses (within the enrichment class of fineness, taking into account permissible refinement and coarsening) or particles of a simulator material having properties similar to that of an enriched mineral. Set standards are transported between the radiation source - x-ray tubes (5 and 6), and detectors (7 and 8) in the form of a monolayer flow on a conveyor belt (2). Over the entire width of the stream, a portion of the material is irradiated with x-ray radiation from the source — x-ray tubes (5 and 6). The maximum size of the irradiated section in the direction of transportation should not exceed the minimum particle size. The signal intensities I (E1) are recorded. and I (E2) of the x-ray radiation transmitted through the standard using devices (7 and 8) containing many sensitive units - pixels and located perpendicular to the direction of flow transport (3). In this case, the intensity distribution I (E1) and I (E2) of the selected energy E1 or E2 of the radiation transmitted through the standard is recorded separately in each energy range. The registration of I (E1) and I (E2) in each energy range can be carried out simultaneously using two linear multi-pixel x-ray detectors located in parallel (one below the other) in the direction of propagation of the irradiating x-ray radiation, while in each of the detectors only one from two selected energy ranges. Depending on the device used for the separation of minerals, registration in each energy range can also be carried out sequentially using two linear detectors located one after the other in the direction of transportation of the standards (Fig. 1). Subsequent processing of the signals I (E1) and I (E2) recorded in this way occurs under the condition that both intensities I (E1) and I (E2) recorded in different energy ranges pass through the same section of the standard. The combination of data in time is performed by computer means (10) by delaying the signals from the pixels of the device (8) for a certain time relative to the same pixels of the device (7). The delay time is defined as t_s= l / v, where l is the distance between the lines of sensitive elements of the devices (7 and 8), and v is the speed of conveyor belt movement. Typical delay value is 15 ... 40 ms. The corresponding signal intensity I is subtracted from the x-ray signal intensity I (E1) and I (E2) recorded through each pixel of the corresponding linear detector 7 and 8, and the corresponding signal intensity I is subtracted₀(E1) and I₀(E2) x-rays with energies E1 and E2, measured on an empty tape (2), and normalized to the maximum possible value of I_max(E1) and I_max(E2) intensities in the corresponding energy range. Thus obtained on a set of standards, the set of pairs of values determines the region 25 (Fig. 3) of the characteristics of the minerals being enriched can be graphically represented as a set of points on the plane with coordinates along the axes I (E1) and I (E2). The remaining pairs of values form region 26, which does not correspond to the characteristic of a useful mineral - diamond.

To eliminate the “edge effect” —false detections of particles of associated minerals on uneven or thin edges of the particles, divide the set of defined points in the range of characteristics of the minerals being enriched into two subsets 25a and 25b depending on the probability of repeating their values in the set of standards: 25a - “definitely useful mineral (diamond) ”and 25b -“ probably a useful mineral ”. Region 26 (Fig. 3), in which signals I (E1) and I (E2) of the x-ray radiation transmitted through the standard are not registered, corresponds to the condition “definitely not a useful mineral”. The selection of subsets 25a and 25b in the region of 25 characteristic values of the enriched minerals (the so-called “ternary” classification) under the condition of maximum selectivity is determined by the priority of detection of a useful mineral.

When processing a diamond-containing source material, the process is similar to the processing of standards, but a computer processing tool (10) generates a pixel-by-pixel distribution of pairs of radiation intensity values I _km (E1) in RAM; I _km (E2) on the plane of the conveyor belt (2) (Fig. 4a). Comparing the values of pairs with the database (Fig. 3), the computer tool selects (Fig. 4b) on the plane of the tape pixels that satisfy the corresponding areas of the comparison database: 25a - “strong points” (specifically, diamond) - black, 25b — weak points "(Probably a diamond) - gray, 26 - definitely not a diamond - white. Connected areas of 27 and 28 pixels corresponding to the areas 25a and 25b of the database are highlighted (FIG. 4b). Objects are finally classified based on their size and the number of “strong” points by the object classification module. Depending on the specified assignment criterion, which determines the size of the connected region in pixels (determined based on the size class of the processed material and the geometric size of the pixel) and the minimum number of pixels related to region 25a, a particle of material 27 (Fig.4b) can be classified as diamond, and particle 28 is not a diamond.

The proposed X-ray mineral separator can be technically implemented as follows: conveyor with motor gearbox VF44 FA1 20P63 B14 B3 - BN63C2W, polyurethane tape 2M5 U2-U2 HP VL BLUE A 200 mm wide, radiation source - X-ray tubes: ("low" energy E1) and (“high” energy E2), for example, of type BXB24-Mo and BXB24-W, respectively, with a high-voltage power source of the type DF75N2X5004 from Spellman, USA, for each tube; detection means in the form of (1 ... 2N) linear X-ray sensitive matrices, for example, S8865-128G from Hamamatsu, Japan, or X-Card2-02-256G (Detection Technology, Finland); The synchronization device can be made in the form of a pulse sequence generator with a frequency of up to 4 MHz on an LPC2148FBD64 PBF chip, a computer processing tool that includes: IBase processor board IBase, Taiwan with a CPU-Core2 QUAD-Q930-2.3 GHz processor and KVR1333D3N9 / 2G RAM ), the ADC array (1 ... 2N) is made on PCI1714UL devices from Advantech, Taiwan (in one board - 4 ADCs 12 bits with FIFO), the input-output device (I / O) can be performed on the basis of the PCI1734 board from Advantech, Taiwan; x, program ROM, auxiliary parameters memory (values of signal intensity of energies I ₀ (Е1) and I ₀ (Е2), measured on a blank tape, maximum value of the radiation intensity range, connectivity parameters, detection criteria) are stored in the Compact Flash module 4GB ; means for deviating the trajectory of particles of a useful mineral are made on the basis of electrically controlled pneumatic distributors VQ21A1-5YOH-C8-LQ manufactured by SMC, Japan.

Example

The proposed X-ray separator was tested for the enrichment of rough diamonds in an enrichment factory using the same type of diamond-free material of a given mass, into which 100 diamonds of grain size from 3 to 6 mm were previously introduced.

Table 1 shows the parameters of the device on which the tests were carried out.

Table 2 shows the test results for the separator.

The tests showed that the proposed separator provides a low number of false detections (1.07), respectively, high selectivity of separation, while maintaining a high percentage of recovery (99%).

Claims (21)

1. X-ray mineral separator containing: a source material transportation unit for organizing a monolayer flow of individual particles, an X-ray source unit configured to irradiate over the entire width of the portion of this stream perpendicular to the direction of its transportation, and the detection unit, made in the form of at least two detector arrays formed by linear x-ray sensitive multi-pixel photodiode arrays mounted perpendicular to the direction of transport of the particles of the source material, for separate registration in different energy ranges of the distribution of radiation intensity transmitted through the irradiated portion of the stream of source material, and the source is x-ray radiation and detector lines are located on opposite sides of the flow hour egg starting material, a block of analog-to-digital converters (ADCs) connected in series with memory devices of the FIFO type, processing unit, made in the form of computer tools, including integrated system bus, CPU, random access memory (RAM) device for collecting and storing digital values of radiation intensity received from the ADC unit, permanent memory devices (ROM) with programs located therein to control the operation of the separator and determine the characteristics of the particles of the feed stream of the material, as well as to store predetermined characteristics of the minerals being enriched and auxiliary parameters, and an input / output device for controlling the separation of particles of enriched minerals from the stream of particles of the source material, moreover, these computer tools are equipped with functional modules that implement the algorithm for assigning particles to an enriched mineral, a unit for separating particles assigned to the mineral being enriched from the feed stream and a block of storage bunkers for separate collection of enriched mineral particles and tailings, characterized in that the output of each matrix of the corresponding detector line of the detection unit is connected to the ADC input and a memory device of the FIFO type of the ADC block connected in series, the outputs of which are connected in parallel to the interface of the processing unit, and the synchronization inputs of each matrix of the corresponding detector line are connected to the output of the synchronization device, while the functional modules include: a module of virtual spatially coupled copies of detector lines for simultaneously entering into each virtual pixel of the virtual detector array matrix a digital value of the radiation intensity signal recorded in the corresponding matrix pixel, a module for determining, for each pair of pixels in the respective detector lines, the characteristics of the particle of the source material in the form of a point in a two-coordinate system, the coordinates of which correspond to the digital values of the signals of the radiation intensities recorded in each pixel of the detector line in two different energy ranges passing through the same particle section, normalized to the maximum possible value in the corresponding energy range, and its verification of belonging to A region of a characteristic value of the characteristics of minerals enriched in ROM a segmentation module for extracting related pixel regions, the particle characteristic value of which belongs to the region of characteristic values of the minerals being enriched and determining the degree of coincidence of the selected pixel region with the region of characteristic minerals of the minerals being enriched, a module for identifying and generating a team for separating particles of an enriched mineral from a stream of source material, according to the degree of coincidence with the criterion for classifying a particle as an enrichable material, the control output of which is connected to the corresponding input of the separation unit to direct particles separated from the stream to the corresponding storage hopper. 2. The separator according to claim 1, characterized in that the block of the x-ray source is made in the form of two x-ray tubes located one after another in the direction of transport of the particles of the source material, each x-ray tube is configured to irradiate the particle stream in only one of two different energy ranges of radiation and opposite each x-ray tube on the opposite side of the particle stream is one of the two detector lines of the detection unit, which is made with possible recording only one corresponding energy range of the intensity distribution of radiation transmitted through the irradiated portion of the source material stream. 3. The separator according to claim 1, characterized in that the detector lines of the detection unit are arranged parallel to each other in the direction of propagation of the irradiating radiation of the X-ray source unit, each of the detectors being configured to record the distribution of the intensity of radiation transmitted through the irradiated portion of the source stream material, in only one of two selected energy ranges.

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