Sorting weakly magnetic minerals first industrial-type separator is dry, until dry high intensity magnetic separator partial still widely used in sorting of manganese ore, iron ore, beach sands, wolframite, tin ores and industrial minerals . Nowadays, the dry magnetic separator has four types: induction roller type, disc type, barrel type and permanent magnet type. The technical performance of the Soviet-made dry electromagnetic induction roller magnetic separator is listed in Table 1. The 164-CÐ type magnetic separator (Fig. 2) is an upper feeding type, which is mainly used to remove weak magnetic iron impurities from various materials. In order to reduce eddy current heating and transmission power, the rollers are laminated with magnetically conductive steel sheets. The rollers have two rows of three rollers. The working principle is shown in Figure 3. The material is fed into the first roller from the hopper to separate the ferromagnetic material; the weak magnetic material enters the second roller to separate the magnetic concentrate; the remainder enters the third roller for sweeping. 2. MIH type double row 6-roll magnetic separator The structure principle of MIH type double-row 6-roll magnetic separator produced by Capco in the United States is the same as that of Figure 3. The MIH231-100 is 2235 × 1651 × 1651 mm; weighs 6.28 tons; the drive power is 2.2 kW; the excitation power is 6.5 kW. The maximum field strength is 2 tex when the air gap width is 4 mm. The treated material has a particle size of 0.074~1 mm. Third, disc and belt magnetic separator The technical performance of the Φ576 mm dry strong magnetic field double disk magnetic separator is listed in Table 3. In the larger concentrator of the Soviet Union, the MC-2 magnetic separator (equivalent to China's Φ576 machine) has been replaced by the 229-CÐ, 233-CÐ and ÐPC-6 induction roller magnetic separators with large processing capacity.
The support grid is made of several Johnson screen sieve plates. Specification and size is customized. Material: 304, 321, 316 L, 904 L, duplex steel 2205, duplex steel 2207, Monel, Ti.etc.
Due to the good mechanical strength, it effectively prevents its own damage and tear in contact with the filler (quartz sand or porcelain ball, etc.) and catalyst ensuring the safe and smooth operation of the reactor in a long period. Therefore, it has gradually replaced the traditional stainless steel woven mesh and perforated plate tray, and has been widely used in petrochemical field.
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I. Induction Roller Magnetic Separator This is the most widely used dry magnetic separator. As shown in Figure 1. The ferromagnetic roller in the magnetic field induces a magnetic field opposite to the polarity of the adjacent magnetic pole on the surface thereof. When the material to be selected falls on the surface of the induction roller, the magnetic material is sucked by the roller, and falls to the receiving material as the roller rotates away from the magnetic field. In the trough, non-magnetic materials fall along their natural motion trajectory for separation purposes.
1. Soviet dry electromagnetic induction roller magnetic separator 
Figure 1 Working principle diagram of induction roller magnetic separator
Figure 2 164—CРelectromagnetic induction roller type strong magnetic separator
1. Electromagnetic system; 2. Coil; 3. Induction roller; 4. Cylinder feeder;
5. Magnetic material according to the trough; 6. Non-magnetic material receiving trough [next]
Figure 3 Working principle of three-stage induction roller magnetic separator
ÐPC-6 two rows of four-roll magnetic separator (FIG. 4) is the lower part of the ore is mainly used for sorting ore and noble metals other weakly magnetic minerals. The upper roll is coarsely selected; the lower roll is selected.
Figure 4 ÐPC-6 electromagnetic induction roller magnetic separator
1. Electromagnetic magnetic system; 2. Roller; 3. Dust collecting pipe; 4. Feeder; 5. Transmission device; 6. Feeder
3. Pn75-2 magnetic separator The Ph75-2 magnetic separator produced by West Grutcher is shown in Figure 5. Raw materials are fed from the top. The roller has a diameter of 100 mm and a length of 800 mm and is made of a laminate of silicon steel sheets. Therefore, even at high speeds (400 rpm), the required driving power is less than 1 kW. The magnetic separator has a device for cleaning the rollers, which regularly remove fine particles from the roll surface.
Second, the rotary magnetic separator
The sorting principle of the CTML type high field strength ring magnet magnetic separator produced by West Germany Humbold Company is shown in Fig. 6. The average field strength of the magnetic separation machine's sorting magnetic field is 1.5 tex. The field strength can be adjusted. The polarity of the poles alternates in the axial direction. The cylinder made of non-magnetic material rotates around a fixed magnetic system, and the rotational speed is adjustable to obtain an optimal sorting index. A groove ring made of a high magnetic permeability material is fixed to the cylinder to rotate between the magnetic poles to bridge the magnetic pole gap. Thus, a concentrated high gradient magnetic field is created within the barrel recess. There is a special feeding device that feeds the material into the groove of the cylinder for sorting. This magnetic separator is mainly used to separate magnetic impurities from materials.
Figure 5 Lucci's Pn75-2 induction roller magnetic separator NM-non-magnetic products, M-magnetic products [next]
Figure 6 CTML barrel type strong magnetic separator sorting principle
Figure 7 CTML type magnetic separator
1. Disc Magnetic Separator The disc magnetic separator currently used in production has three types: single disc (900 mm in diameter), double disc (576 mm in diameter) and three discs (600 mm in diameter). The structure of the Φ576 mm machine manufactured in China is shown in Figure 6-3-30. The magnetic system is in the shape of a mountain, and the closed magnetic circuit is formed by a vibration groove (or a belt) and a disk. The sorting process takes place in the air gap between the groove face and the edge of the disc. The air gap spacing can be adjusted. In order to prevent the strong magnetic material from interfering with the magnetic separation process, a weak magnetic field magnetic separator is installed at the feed end.
Figure 8 Φ576 mm dry strong magnetic field double disk magnetic separator
1. Feeding hopper; 2. Feeding cylinder; 3. Strong magnetic product receiving hopper;
4. Screen trough; 5. Vibrating trough; 6. Disc; 8. Magnetic system
[next]
2. Belt magnetic separator The structure of HCB type cross belt type strong magnetic separator manufactured by Eliz Company is shown in Figure 9. The industrial magnetic separator has a maximum of 8 magnetic poles, and the main feed skin has a bandwidth of 610 mm. The magnetic field of each pole can be adjusted.
Figure 9 HCB cross belt magnetic separator
Fourth, permanent magnet roller magnetic separator
The American Batman Company developed a permanent magnet roller magnetic separator (PERMROLL) using a samarium cobalt alloy magnet. The structure of the permanent magnet roller is as shown in FIG. It is a set of round rolls that are superimposed between a permanent disk and a floppy disk. The magnetic separator is formed by a thin and wear-resistant electrodeless belt around the magnetic roller (Fig. 11). This sorting structure allows even the particles of the ferromagnetic material to be removed. The surface magnetic field of the roller was determined to be 1.7 tex. This magnetic separator has been used in the concentrator. Israel's Negve Ceramics has replaced the original Induction Roller Magnetic Separator (IMR) with a Permroll machine.
Figure 10 Schematic diagram of permanent magnet roller structure
Figure 11 Schematic diagram of 3Permroll type magnetic separator
The performance comparison of the two magnetic separators is shown in Table 4. 
Dry strong magnetic field separator
Table 1 Dry electromagnetic induction roller magnetic separator technical performance
parameter
164-CÐ
229—CÐ
250-CÐ
233-CÐ
ÐPC-6
8ÐPC—B-
16/100
MC-2
Roll size, mm
diameter
length
Number of rolls
The mineral matter size, mm <
Roller tooth surface magnetic field strength, kA/m
Roll rotation number, r/min
Production capacity, t/h
Excitation power, kW
Transmission power, kW
100
800
6
2
1270
58
1.6~3
0.7
3.0
280
90
1
3
1590
75~300
To 0.7
0.75
1.5
360
500
1
3
1430
75~250
To 4
1.65
7.5
360
1000
2
3
1350
75~250
To 15
6.6
15.0
360
1000
4
2
1350
85~170
To 7
8
16.0
160
1000
8
2
1400
90~250
To 16
9.86
twenty four
576
-
2
2
1300
39
To 0.5
1.3
3.0
Magnetic separator size, mm
long
width
high
Machine weight, t
1900
2050
2360
6.34
810
1360
1800
0.96
1880
1550
1850
3.7
2650
2100
2000
7.8
2260
2205
2000
12.6
2905
2040
3120
18.7
2339
858
1130
1.7
Table 2 CTML type magnetic separator specifications
model
size
Yield, t/h
Transmission power kW
Excitation power kW
Barrel speed
r/min
Speed ​​changer
r/min
L
B
H
4
6
8
12
1790
1790
1790
1890
2000
2240
2480
2960
1700
1700
1700
1700
0.7~1.0
1.1~1.3
1.4~1.6
2.2~2.4
1.4
2.2
3.0
3.0
1.8
2.68
3.52
5.35
48
48
48
48
34~143
34~143
34~143
34~143
Table 3  Technical performance of Φ576mm dry magnetic field double disk magnetic separator
parameter
Numerical value
parameter
Numerical value
Processing capacity, t/h
Feeding particle size upper limit, mm
Feed limit ratio magnetic susceptibility, m 3 /kg
Magnetic field at a rated current gap of 2 mm
Strength, kA
Number of discs
Disk diameter, mm
Disk rotation number R/mm
Vibration groove working width, mm
Vibration groove stroke, min -1
Vibration groove stroke, mm
Feed cylinder rotation number, r/min
0.2~1
2
5*10 -7
1512
2
576
39
390
1200, 1700
0~4
34
Number of exciting coils
Excitation coil rated current, A
Excitation coil temperature rise, °C
Motor power, kW
disc
Vibration tank
Feeding cylinder
Magnetic separator size, mm
long
width
high
Machine weight, kg
6
1.7
60
1
0.6
0.25
2320
800
1081
1650
Table 4 Â Performance comparison between induction roller magnetic separator and Permroll machine (long roll per meter)
parameter
Induction Roller Magnetic Separator (IMR)
Permroll magnetic separator
Highest field strength
Magnetic field gradient
Air gap
Energy consumption
weight
Roller wear
operating
1.6T
80T/m
The feedstock blocks the air gap during continuous production, and the production capacity decreases.
2kW/m
10t/m
Magnetic roller is in direct contact with the feedstock
Complex gap and current regulation
1.6T
300T/m
No air gap, no feeding
0.2kW/m
0.25t,m
Magnetic roller is protected by belt
Very easy, just replace the belt