After the raw ore is coarsely crushed and sieved, it is sent to the belt feeder by two-stage electric vibration to the mining machine and the skateboard. According to the particle size of the ore, the ore has been divided into two, three, four or five ores on the electric vibration feeder. Flow, on the belt feeder, the ore is arranged in a single row that is connected end to end. The ore leaves the belt and is fed to the main belt via a multi-slot stabilizer. The main belt runs at a speed of 5.1 m/s, which is three times the speed of the ore belt. Therefore, the nuggets are pulled apart from each other on the main belt and passed through a conductance-magnetic detector. The detector is a planar coil mounted underneath the belt and emits radio waves of approximately 10 megahertz per second. This coil is both a radio wave source and a nugget detector. According to the current of the transmitting coil, the phase, amplitude and frequency of the voltage change to determine the conductivity and magnetic susceptibility of the nugget on the detector, thereby distinguishing the ore from the waste rock. The number of detectors varies within a certain range depending on the size and characteristics of the ore. And the amount of gold metal nuggets were collected signal is proportional to the measured probe and stored in the electronic information processor.
After the ore leaves the main belt, the photoelectric particle size detector measures the cross-sectional area of ​​the ore and its position during the falling process, and sends the result to the information processor.
The information processor compares the amount of metal in the nugget with the particle size to obtain the nugget metal grade. By comparing this grade with a predetermined value, it can be determined whether the ore is a concentrate or a waste rock. When it falls to the front of the nozzle, the information processor sends a command to the electromagnetic jet valve to start the solenoid valve, and the compressed air with a pressure of (6.5~7)×10 ⁵ Pa is ejected from the nozzle, so that the nugget deviates from the normal running track. This separates the natural falling ore and obtains two products, fine and tailings.
The M19 conductivity-magnetic separator has the functions of indicating the uniformity of each channel, automatically recording the ore grade, the grade of the concentrate tailings and the yield of the blown product, and has various alarm devices.
It should be noted that the M19 sorter is basically identical in structure to the M17 radioactive sorter (see Figure 18), and only detectors that detect ore characteristics are different. If the radioactive detector of the M17 sorter is replaced by a conductance-magnetic detector and the corresponding change is made in the information processor, the M17 sorter can become the M19 sorter, so the M17 and M19 The schematics can be cross-referenced.
B M27 sorting machine M27 sorting machine was successfully developed by RTZ Ore Sorting Machine Company in 1985. The principle is exactly the same as that of M19. The structure diagram of sorting machine is shown in Figure 24. [next]

After the raw ore is coarsely crushed and sieved, it is fed from the mine bin to the second-stage four-slot electric vibrating feeder 2 through the first-stage electrovibrating feeder 1, and the four parallel ore streams formed are flown onto the sliding plate 3. Due to the acceleration of gravity, the distance between the ore is opened. The conductance-magnetic detector 4 mounted on the lower side of the tail of the slide detects the conductance-magnetism of each ore, and then the solid imager 5 detects the size of the ore and its position in the ore flow. The micro-computer calculates the grade of each ore based on the two signals obtained by the detector, and then determines whether it is a concentrate or tailings compared to the predetermined cut-off grade. The electromagnetic jet valve 6 blows the mine (or tailings) away from the normal operating trajectory.
Eight, gamma scattering sorting machine Outokumpu of Finland developed the Precon Precon sorting machine in the early 1980s. The sorting machine uses the gamma scattering method to select ore.
The Precon ore sorter uses two gamma sources of different energies. One source relates the scattering activity of the ore to the weight of the nugget, and the other source relates the scattering activity of the ore to the weight of the nugget and the effective (weighted) atomic number. Compared to the two activities, a parameter is obtained which is independent of the size and shape of the nugget and only relates to the effective atomic number of the nugget. In this way, the ore block with large atomic number and heavy metal element can be successfully separated from the surrounding rock. [next]
A schematic diagram of the Precon-type ore sorting machine is shown in Figure 25.

The coarsely crushed, sieved ore is fed from the mine bin to the vibrating feeder 1 . The feeder divides the ore into two strands and respectively slides them onto the respective belts 2, and the belts are made into a "V" shape so that the ores are arranged in a single row. The belt speed is 0.8~2 m/s. After leaving the belt, the ore falls in a parabolic trajectory and gradually pulls away during the falling process. The nugget first passes through the light source 3. When the nugget blocks the light source, the photocell on the opposite side of the light source generates an electrical pulse signal, which signals that the microprocessor nugget has entered the detection zone. When the nugget reaches the middle of the γ-ray detection zone 4, the nugget speed is 4~5 m/s, and the distance between the nuggets is about 80-100 mm. There are two sets of illumination sources and one scintillation detector in the detection area. Each group of illumination sources consists of two y-ray sources with different energies, such as ²⁴¹ Am (é•…) and ¹³⁷ Cs ( 铯 ), and their energy is about 60 thousand electrons respectively. Volt and 600 keV, the gamma-rays scattered by the ore after being irradiated are detected by a scintillation detector with a detection time of 20 to 50 milliseconds. The microprocessor calculates the grade of each nugget based on the measurement results of the two sets of illumination sources. If the obtained grade exceeds the predetermined grade of the microprocessor, the electromagnetic jet valve 5 is activated to blow the nugget away from the normal running track, thereby sorting Two products of fine and tailings 6 . [next]
The Precon type sorting machine can also separate three products of fine, medium and tailings. To get three products, add an air injection device to the opposite side of the original jet valve.
The throughput of each channel of the Precon-type sorter varies with the size of the nugget, see Figure 26.

Nine, γ absorption method sorting machine Soviet Union developed the Mинерал-50г type sorting machine in 1985. The sorting machine utilizing waste rock and ore-ray absorption difference Γ- ability to pick dressing stone, γ- radiation source is used ^{241 Am.Mинерал-50г} type sorter is shown in Figure 27. [next]

The coarsely crushed and sieved ore is fed from the silo 1 to the vibrating screen to the mining machine 2 for washing and sieving the fine particles. After the sieved product flows to the vibrating screen 4, the water and slime are separated. The product on the screen is fed to the intermediate mine 5 and then to the vibrating feeder 6. The bottom plate of the mining machine is step-accelerated, and the moving speed of the ore block is increased, so that the height of the ore flow is gradually decreased. At the exit of the mining machine, the ore flow has become a single layer, and the running speed of the ore block is 0.5~1.0 m. /second. The nuggets are fed onto a transport belt 7 of 800 mm width, which is stabilized on a transport belt having a speed of 3 m/sec by means of a belt stabilizer 9 with a brush. The x-ray source 12 is placed under the belt and the gamma detector (14) is placed over the belt. The n-ray energy absorbed by the nuggets of different chemical compositions through the detection zone 10 is different, and the signals given are also different. The radiometer 16 activates the corresponding air injection valve 15, and the two products of the fine and tailings can be sorted.
X. Picking equipment summary
The new picking equipment is constantly being replenished and developed, and the main picking equipment that has been announced is now aggregated.

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