RU2211732C1 - Magnetic separator - Google Patents

Abstract

FIELD: equipment for separation of metal-magnetic impurities from flow of loose diamagnetic materials; applicable, for instance, in removal of metal-magnetic impurities from grain flow at receiving elevator. SUBSTANCE: magnetic separator includes magnetic system consisting of rectangular permanent magnets facing each other by like poles and separated by ferromagnetic concentrators projecting beyond limits of magnetic units into separation working zone. Magnetic system is made with inclination and installed on two semiaxles or axle for bringing beyond limits of body for cleaning. Height of concentrators varies to 250 mm over length of magnetic system. Angle of inclination varies within 10-110 deg. EFFECT: higher efficiency of process of impurities removal from thick flow of loose material due to optimal utilization in separator design of process separating forces (magnetic and gravitational forces). 3 cl, 5 dwg

Description

FIELD OF TECHNOLOGY
The invention relates to a device for extracting metallomagnetic impurities from a flow of bulk diamagnetic material (separation) and can be used for this purpose in the elevator, animal feed, flour and cereal industry, in the enrichment of minerals, in the preparation of molding mixtures.

BACKGROUND
Known magnetic separator, comprising a magnetic system consisting of rectangular magnetic blocks located one above the other, facing each other with the same poles, and ferromagnetic concentrators between these blocks. Thus, magnetic blocks and hubs form a vertically arranged magnetic system. The magnetic system is mounted on the door of the rectangular cage of the separator. Bulk material to be separated flows around the magnetic system on four sides. The separator also includes inlet and outlet nozzles (A description of the design is given in the article "Experience in the development of magnetic columns", authors Meshcheryakov I., Anikeeva L., magazine "Feed" 1, 2000).

 The disadvantage of this magnetic separator is that the layout of the magnetic system is made with a vertical alternation of concentrators. The metal-magnetic particle moving between the concentrators in the stream, which is to be removed, acquires additional acceleration in the direction of the outlet pipe. The design of the magnetic system provides for the implementation of working hubs on all four sides of the magnetic blocks. The separation perimeter with this design is increased, and the scattering of the magnetic flux occurs along the concentrators on all four sides. When separating large metallomagnetic impurities from a powerful separated product stream, this design is ineffective.

 Known magnetic separator according to British patent 2132918, 03 With 1/12, publ. 07/18/1984, including a magnetic system consisting of permanent magnets facing each other with the same poles and separated by ferromagnetic concentrators. The separator is selected for the prototype.

 The disadvantage of this separator is the small working length of the disk magnet and hub. The separation efficiency in this design is insufficient for the reason that the force of gravity acting on the recoverable impurity does not always coincide in direction with the magnetic field strength.

 In order for the gravity acting on the extracted impurity to be closer to the magnetic field strength, the magnetic system of the separator must be inclined and form inclined channels for separation, which is implemented in the proposed separator.

 Ferromagnetic concentrator separator prototype protrude beyond the magnetic blocks on all four sides, which involves the dispersion of magnetic flux on all four sides of the concentrators. When extracting impurities from a powerful stream of raw materials during reception, it is necessary to concentrate the magnetic flux in one direction to strengthen the field, which is done in the proposed separator.

SUMMARY OF THE INVENTION
A magnetic separator comprising a magnetic system consisting of permanent magnets facing each other by the same poles and separated by ferromagnetic concentrators, characterized in that the magnetic system is made in the form of magnetic blocks, while the permanent magnets are made in a rectangular shape, the ferromagnetic concentrators of the magnetic system are made flat and protruding beyond the limits of the magnetic blocks into the working separation zone, have an increasing height along the length of the magnetic system, and the magnetic system is made on slope and is mounted on two half-axes or axis to output outside the housing of the separator for cleaning.

 Thus, magnetic blocks and concentrators form inclined channels of increasing depth along the length of the magnetic system (along the flow of bulk material). Bulk material moves along these channels and above them and magnetic separation occurs. In the area where bulk material enters the magnetic system, the bulk material moves on top of the channels.

The inclination of the magnetic system of the separator provides the use of gravity force F _T for magnetic separation, since the force of gravity F _T directed vertically downwards in this design has a direction close to the direction of the magnetic force of attraction F _mag and, thus, helps to extract metallomagnetic impurities (see figure 1).

 Changing the height of the concentrators along the length of the magnetic system provides an increase in the efficiency of the process due to efficient separation along the entire thickness of the separated layer (provides an effective surface and depth separation process), since both the lower and upper layers of the flow of bulk material are located above the concentrators along the length of the magnetic system.

 Changing the height of the concentrators along the length of the magnetic system also ensures that the flow of bulk material from impurities extracted to the concentrators is prevented from being washed away by the concentrators from the most dense bulk flow of concentrates.

In addition, a change in the height of the concentrators entails a change in the basic parameters of the magnetic field of the working zone of the separator — the magnetic system F _mag and the gradient of the field strength grad H, which creates optimal conditions for the extraction of impurities of different particle sizes. The proposed construction is most optimal for the extraction of large impurities, since the gravity force F _T acting on the impurity is a percentage more significant part in relation to other forces involved in the separation process for large metallomagnetic impurities.

LIST AND DESCRIPTION OF FIGURES
A diagram of the forces acting on a ferromagnetic particle during the separation process in the field of the magnetic system of the proposed separator is shown in figure 1.

- вектор действия магнитной силы;

- вектор действия силы тяжести;

- вектор действия силы инерции.

- the action vector of the magnetic force;

- the vector of action of gravity;

is the vector of action of the inertia force.

близко к направлению действия

в предлагаемой конструкции сепаратора.From the diagram it follows that the direction of the force

close to the direction of action

in the proposed design of the separator.

 The diagram shows that the metal-magnetic particle extracted and held by the concentrator 2 is located above the upper boundary of the dense separated layer, therefore, it does not experience the flushing action of the flow of bulk material.

 A general view of the magnetic separator in two projections is shown in Fig.2-3.

 The separator consists of a magnetic system, including magnetic blocks 1 and ferromagnetic concentrators 2. The magnetic system is located in the housing 3 on two half shafts 6, providing it with a rotation of 90 degrees or more. The support of the magnetic system and the entire separator is carried out on vertical posts 7.

 In the working position, the magnetic system is fixed by two clamps 8.

 The separator also includes inlet 4 and outlet 5 nozzles.

Information confirming the possibility of carrying out the invention
Based on the materials of the invention, a prototype magnetic separator with a capacity of 175 t / h for grain raw materials was developed and manufactured.

 The separator is mounted in front of the receiving elevator of the grain raw materials on the elevator. A general view of the magnetic separator in two projections is shown in figure 2. The separator works as follows.

 The bulk material to be separated enters the separator housing 3 through the inlet pipe 4 and reaches the beginning of the magnetic system consisting of blocks 1 and concentrators 2. The bulk material flows by gravity through the magnetic system along the channels formed by the magnetic blocks 1 and concentrators 2, and above these channels. Metallurgical impurities are attracted to the concentrators and held by them, and the purified material exits through the outlet pipe 5.

 Cleaning ferromagnetic concentrators from the extracted impurities is carried out periodically. When the supply of the separated material is stopped, the locks of the magnetic system open, and the magnetic system rotates on the axle shafts (is displayed) outside the separator body. Ferromagnetic concentrators are cleaned of impurities, and the magnetic system returns to its original position and is locked with locks to the housing. The separator is ready for operation.

 A general view of a magnetic separator with a magnetic system brought out (rotated) on the half shafts outside the housing for cleaning is shown in Fig. 4.

 The magnetic system for cleaning is removed outside the housing periodically when the supply of bulk material ceases.

 A photograph of a General view of the magnetic system for a prototype magnetic separator with a capacity of 175 t / h for grain raw materials is presented in figure 5.

 The magnetic system of the prototype separator has 6 (six) ferromagnetic concentrators and 5 (five) rows of magnetic blocks.

 The change in the height of the concentrates above the magnetic blocks in the prototype of the separator: from zero (the beginning of the magnetic system) to 120 mm (end of the magnetic system).

 The angle of inclination of the magnetic system in the prototype is 45 degrees, with a length of the magnetic system of 595 mm.

The magnetic system is mounted on two half shafts and has a support on racks. In this design, the ranges of changes are possible:
- the angle of inclination of the magnetic system is 10 ÷ 110 degrees;
- concentrator heights - up to 250 mm.

 Ferromagnetic concentrators protruding beyond the magnetic system into the working area (only on one side) provide a concentration of field strength only in this working area, as a result of which the magnetic induction on the surface of the concentrator will increase to 350 mT. (The maximum magnetic induction on the surface of the concentrator of the prototype separator is 270 mT).

Magnetic induction along the edge of the concentrator (on its surface) on the magnetic system of the prototype separator is changed as follows:
- 350 mT - at the beginning of the magnetic system (with a height of concentrators equal to zero, when the concentrator does not protrude beyond the limits of magnetic blocks);
- 290 mTl - at the end of the magnetic system (with a height of concentrators - 120 mm).

 In this case, the magnetic induction gradient along the edge of the concentrator is directed toward the beginning of the magnetic system, i.e. an inhibitory effect is observed for a particle that is attracted to an edge.

The measurements were carried out on the magnetic system of a prototype separator with dimensions:
- the length of the magnetic system is 595 mm;
- width of the magnetic system - 470 mm;
- the height of the magnetic blocks is 70 mm;
- concentrator height range - 0 ÷ 120 mm;
- step of the magnetic system - 89 mm;
- coefficient of pole overlap - 0.95.

The height of the dense layer of separated grain (bulk density 0.75 t / m ³ ) with a separator capacity of 175 t / h was 80 mm.

 The extracted metallomagnetic impurities turned out to be distributed over the edges of the concentrators of the magnetic system. A significant part of the impurity was in the zone of concentrators with a height of ≥ 80 mm and, thus, was not exposed to the washing-off flow of grain. The impurities extracted by the concentrators in the flow zone were kept on the concentrators for several hours as a result of the action of significant attractive forces on them, which take place in the proposed design.

The efficiency of the extraction of impurities in the prototype of the separator increased to 95% compared with the separator prototype (90%), which is a significant indicator. The increase in separation efficiency was also a consequence of the fact that the magnetic system in the separator is made with an inclination. With this design, the gravity force F _T acting on the impurity is close to the magnetic force of attraction F _mag . The positive effect of gravity F _{T is} especially noticeable in the separation of large impurities (larger than 10 mm) on this design of the separator.

Claims (3)

 1. A magnetic separator comprising a magnetic system consisting of permanent magnets facing each other by the same poles and separated by ferromagnetic concentrators, characterized in that the magnetic system is made in the form of magnetic blocks, while the permanent magnets are rectangular in shape, the ferromagnetic concentrators of the magnetic system are made flat and protruding beyond the boundaries of the magnetic blocks into the working separation zone, have an increasing height along the length of the magnetic system, and the magnetic system it is inclined and mounted on two half shafts or an axis with the possibility of withdrawing outside the separator body for cleaning.  2. The separator according to claim 1, characterized in that the height of the concentrators of the magnetic system is changed to 250 mm. 3. The separator according to claim 1, characterized in that the angle of inclination of the magnetic system varies between 10-110 ^o .

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