WO2019035729A1

WO2019035729A1 - Pneumatic method of separating mineral and technogenic raw materials according to particle shape

Info

Publication number: WO2019035729A1
Application number: PCT/RU2017/000594
Authority: WO
Inventors: Андрей Иванович СТЕПАНЕНКО
Original assignee: Андрей Иванович СТЕПАНЕНКО
Priority date: 2017-08-17
Filing date: 2017-08-17
Publication date: 2019-02-21
Also published as: EA201900111A1; EA037602B1

Abstract

The invention relates to the field of separating mineral and technogenic raw materials and can be used for producing mobile separating plants intended for processing and classifying raw materials according to shape in virtually any weather conditions, including at ambient air temperatures of -50 to +50°C. A pneumatic method of separating mineral and technogenic raw materials according to particle shape is claimed, comprising placing raw materials to be processed on an air-permeable surface in the form of a conveyor that passes below the base level of a separating chamber, in which a volumetric pseudo-boiling layer of particles having a specified density is formed by selecting an airflow velocity. Particles of smaller density enter into and pass through said layer without obstruction and are then transferred by a rising airflow from a vertical chamber into a gravitational settling chamber. The invention is novel in that an additional stream of air, tangentially oriented towards a wall of the separating chamber, is directed into the separating chamber and creates auxiliary eddy flows at the walls and the base of the chamber, after which particles of flat, needle-like or thread-like shape are lifted by a rising flow of air and are transferred to the gravitational settling chamber, in which one or more cross-directional eddy flows depositing the particles in the chamber is/are created, from which chamber said particles are removed.

Description

Pneumatic method of separation of mineral and technogenic raw materials in the form of particles

The invention relates to the field of enrichment of mineral and technogenic raw materials and can be used to create mobile enrichment plants for processing and classifying raw materials according to the form in almost any weather conditions, including at ambient temperatures from -50 to + 50 ° C.

Prior art

It is known that the processing of raw materials to obtain products of the required quality is performed by physical methods according to various parameters, such as size, density, magnetic susceptibility, etc. One of these parameters is the shape of grains. It is often necessary to separate materials that are similar in their basic properties, but differ in shape. For example, in the rubble going to road pavements and construction, the content of grains having a lamellar form or flax grains is regulated. This is due to the fact that planar grains are less durable, as well as reduce the carrying capacity of bulk materials by reducing the adhesion forces between the grains. The traditionally low content of flaky grains is provided through the use of multi-stage rock crushing schemes with a small reduction in the size of the product at each stage. This solution leads to a high dropout rate of 0-5 mm class, which refers to low quality products and has limited use. For example, in the production of crushed stone of classes 5-10 mm and 10-20 mm, which are most in demand in road construction, 0-5 mm screenings are formed in an amount from 60 to 75%. At the same time, the more durable and valuable rock is used in the production of rubble, the greater the yield of dropouts. When using crushing schemes with fewer stages, the dropout rate is reduced to 30-35%, but the resulting gravel contains flat grains in larger quantities and must be removed from commercial gravel. It becomes clear that the further development of enrichment technologies is impossible without effective technologies that provide for separation according to form. At the same time, the technology of enrichment of raw materials in form must meet several stringent requirements. First, the method should be universal, easily rebuilt for the processing of various types of mineral raw materials (crushed stone, asbestos, mica and other mineral or man-made products).

Secondly, the method of processing must provide for the possibility of quickly and smoothly changing the technological regimes depending on the properties of the processed raw material (mass and particle size, density and shape), which will allow the creation of mobile concentrating plants of modular type using the same type of equipment with a low level of capital costs for their delivery and installation.

Thirdly, the method of enrichment of raw materials should be highly efficient, ensuring high quality of the products obtained, as well as ensuring that after its use only those wastes that are not suitable for further processing or direct application remain. Fourthly, the technology of enrichment of raw materials should be all-weather and year-round in order for the process to take place not seasonally with temporary attraction of labor resources, but go all the time — with year-round employment of the local population. For this reason, the enrichment process cycle must include an ambient air temperature range from -50 to +50 ° C and should allow equipment to be placed under an open sky or with the use of lightweight shelters.

There is a method of separating bulk material in the form (patent RU

21 19393, Cl. VV07B 13/00, 1998), in which, due to the difference in friction forces and the dynamic characteristics of particles of a flat (blade) and cuboid shape, the particles are separated by feeding the material on an inclined plane with a subsequent collision with a rotating cylindrical by the surface.

The main disadvantage of this method is the low separation efficiency and the possibility of implementing the process only on coarse material, despite the fact that it is necessary to recycle to a greater extent fine material in the industry. Analysis of waste materials from the processing of natural materials with the extraction of mica using a similar technology showed that as a result, about half of the commercial mica with a grain size of 13-50 mm was lost, and the extraction of mica in smaller classes did not occur at all.

The closest to the claimed technical solution is the method of pneumatic enrichment of mineral raw materials (see. Eurasian patent N ° 022959, Cl. B07B 4/08, B03B 4/04, 2016), including placing enriched raw materials on an air-permeable surface that intersects a vertical chamber with an ascending air flow, lifting light fractions from an air-permeable surface, made in the form of a conveyor, missed below the bottom of the vertical base chamber, in which the choice of the air flow rate forms a volume pseudo-boiling layer of particles of a given density, into which particles of a lower density fall and pass freely through it, and then ascending a sound stream is transferred from the vertical chamber to the gravitational sedimentation chamber. When using this method, it is possible to separate materials not only in terms of density, but also in form, due to the fact that planar or needle-shaped grains have a greater ratio of the aerodynamic drag force to the particle weight.

The known method allows for year-round enrichment of raw materials in the open air or with the use of light-weight shelters, as well as a quick reorganization of the technological process for the processing of various types of mineral raw materials by changing the air flow rate.

The main disadvantage of this method is its functional limitations in the separation of mineral and technogenic raw materials, which contain many flat or filamentary particles.

Firstly, this is due to the difficulty of lifting from the conveyor by the vertical flow of those particles whose length, width, and height can vary by several dozen times. Such thin flat or filamentary particles can be turned into a vertical suction flow with their narrow face or needle end, while their aerodynamic properties when exposed to the suction flow will differ greatly from the properties of the particles lying on the conveyor flat.

Secondly, this is due to the fact that the deposition chamber does not allow capturing thin flat or filamentary particles due to their slow speed of air in air, and, therefore, to ensure their deposition, it is necessary to disproportionately increase the size of the deposition chamber.

DISCLOSURE OF INVENTION

This invention is based on the task of expanding the functional capabilities of the pneumatic method of separating particles, which can enrich particles of different types differing in shape by various degrees. mineral raw materials and industrial wastes, such as mica, asbestos ore, gravel, and household waste.

This task in the pneumatic method of separating mineral and technogenic raw materials in the form of particles, including placing the processed raw materials on an air-permeable surface made in the form of a conveyor, running below the level of the lower base of the separation chamber, in which a volume pseudo-boiling fluid is formed a layer of particles of a given density, into which particles of lower density get into and freely pass through it, and then are transferred by ascending air flow from The vertical chamber is gravitationally deposited by an additional air flow directed tangentially oriented towards the chamber wall into the separation chamber, creating auxiliary vortex flows near the walls and the lower base of the chamber, and then the ascending air flows , needle-shaped or filiform and transfer them to a gravitational sedimentation chamber, in which they create one or more counter-directed vortex flows, precipitating the particles in the chamber, from which they then remove are.

Due to the additional air flow tangentially oriented to the chamber wall, it is possible to create eddy air flows against the walls and base of the separation chamber, and thus avoid sticking of the particles of the separated raw material to the walls of the separation chamber with the formation of agglomerates of particles, and also act on the base of the chamber thin, flat or filamentary particles that, with their narrow face or needle-like end facing the vertical suction flow, in order to change their spatial surface and therefore improve their interaction with the suction flow. In this case, in the gravitational deposition chamber, one or more vortex flows directed opposite to the particle motion are created, which sharply reduce the kinetic energy of the moving particles, which leads to their rapid deposition on the bottom of the chamber.

To create controlled vortex flows near the walls of the separation chamber, capable of exerting a predetermined vortex effect on thin flat or filamentary particles that, with their narrow edge or needle-like end facing the vertical suction flow, are additional tangential oriented stream of air is fed through a tangential nozzle, which is installed with the possibility of changing its position in the vertical plane.

Since each emitted fraction of particles has its own aerodynamic properties, the speed of an additional tangentially oriented air stream is selected experimentally.

To perform simultaneous multi-stage pneumatic separation of mineral and technogenic raw materials into particles of a given shape and dimensions of a flat, needle or threadlike shape, several separation chambers are sequentially installed, each of which selects individual parameters to select particles of a given shape and dimensions, while each chamber is connected to its own gravitational deposition chamber.

To remove the particles deposited on the walls of the gravitational sedimentation chamber, a contact method of exposure is used, for example, by mechanical scrapers, or a contactless method, for example, by exposure to an air stream or a combination of both of these methods.

Thus, the claimed pneumatic method of separation of mineral and technogenic raw materials in the form of particles allows the separation of mineral raw materials into almost any number of fractions having different shapes during one cycle of movement on the conveyor, while the method separates fractions with high efficiency and productivity that has no analogues among known methods of pneumatic separation of thin flat or filamentary particles, and therefore, meets the criterion of "inventive step".

Brief Description of the Drawings

The inventive method is illustrated by the drawings shown in FIG. 1-2. Figure 1 presents the setup for the implementation of the proposed method of separation of mineral and technogenic raw materials in the form of particles, where: 1 - air-permeable conveyor with particles of enriched mineral raw materials 2; 3 - separation chamber with a lower base 4, a tangential nozzle 5, forcing air flow 6, and a mechanism for turning the direction of the jet 7; the upper part of the separation chamber 3 is connected by the air duct 8 to the gravitational deposition chamber 9, the lower base of which 10, is equipped with a rotary sluice gate 1 1 for periodically pouring out the particle-shaped fraction 12 of the raw material 12; the deposition chamber 9 through the duct 13 is connected to the exhaust fan 14; 15 - tangential duct, creating a stream of air 16, opposite to the stream of air 17 with particles of raw materials entering the chamber 9; 18 - air flow without raw materials, sucked from the chamber 9.

Figure 2 shows a drawing of the separation chamber 3 in isometry and shows the vortex flows inside the chamber: 19 — near-wall vortex flow, 20 — axial vortex flow.

The best embodiment of the invention

The implementation of the proposed method will consider the installation shown in Fig.1. 2, a diagram of the vortex flows inside chamber 3 is visible. Particles of the separated raw material 2 are evenly placed on the surface of the air-permeable conveyor 1 and move towards the separation chamber 3. Once under the base of the chamber 4, the raw material 2 falls into the zone of the volumetric fluidized bed particles of a given density, formed as a result of the upward flow of gas created by the fan 14 through the air ducts 8 and 13. The separation of particles in shape occurs due to the difference in mass and aerodynamic resistance particles of different shapes. The particles that are close in one linear size, but differing in one or two linear sizes, have different mass and aerodynamic resistance. For example, flat particles have a mass several times, and sometimes several tens of times less than conventionally cuboid or spherical particles, while the aerodynamic drag of flat particles is significantly higher than the resistance of spherical particles. The difference in properties leads to the fact that the speed of the soaring of particles of different shapes is significantly different. The same is true when comparing needle-like or filamentary particles with flat or spherical or cubic particles. Having found themselves in the zone of the pseudo-boiling layer, the particles begin to circulate in it, and those that have a soaring speed less than the flow rate in separation chamber 3 are removed with flow 17 through the duct 8 to the deposition chamber 9. Particles with a higher velocity The headings are returned to the conveyor 2 and removed from the zone 4 of the separation chamber 3. Simultaneously with this process, the air flow 6 enters the chamber 3 through the tangential nozzle 5. As a result of the impact of the wall vortex flow 19 (see Fig. 2) sticking of particles with pariruemogo feedstock 2 to the walls of the separation chamber 3 to form Ratov agglomeration of particles and to create eddy currents in the walls and the lower base separable chamber 4, and thereby affecting thin flat or filamentous particles that, with their narrow face or needle end, face the vertical suction flow and cannot, due to poor aerodynamic properties, be sucked only by the vertical flow 20. Particles under the influence of stream 19 is rotated, their aerodynamic properties are improved and they are captured by stream 20. Next, the captured particles with stream 17 enter the gravitational deposition chamber 9, the lower base of which 10 is equipped with a rotary gate The internal damper 1 1 for periodically pouring out the fraction of raw materials selected by the particle shape 12. When the gravity chamber is operating in the deposition mode, the rotary sluice gate 1 1 is closed. At the same time, towards the air flow 17, the air flow 16 arrives, the speed of the particles drops sharply, their aerodynamic properties deteriorate and they fall under the action of gravitational forces to the bottom of the deposition chamber 9.

Technical applicability

The specific implementation of the proposed method will consider the examples of enrichment of various mineral raw materials.

EXAMPLE 1.

Consider the separation of phlogopite ore. The pneumatic enrichment process was carried out on an experimental setup presented in FIG. Prior to processing, the ore is pre-crushed to a particle size of 0–16 mm and fed to a belt conveyor 1, with a web made of a mesh with a 1 mm cell, 600 mm wide and moving at a speed of 0.5–1.5 m / s, over which successively one after another there are two cylindrical chambers 3 with tapered bases 4 equal to the width of the conveyor — 600 mm. The cylindrical part of the chamber has a diameter of 1200 mm and a height of 2000 mm. Each of the chambers is connected with its gravitational sedimentation chamber 9 in the form of an inverted truncated cone with a diameter of the upper base of 2400 mm, a lower base of 900 mm and a height of 3200 mm. The deposition chamber 9 has a design that provides for the formation of two oppositely directed vortices 15 and 17, while the vortex 15 is driven into the chamber 9 tangentially clockwise to its wall, and the vortex 17 is also tangential, but counterclockwise . Ore particles 2 with a size of less than 1 mm wilt under the grid of conveyor 1, fall on a vibrating chute (it is conventionally not shown in Fig. 1) and are removed from further processing. The air flow in chambers 3 is selected in such a way that in the first separation chamber there is a product represented by phlogopite plates with a thickness of less than 0.1 mm, and in the second chamber there are grains with a thickness of up to 1 mm. The material remaining on the conveyor is represented by grains of rubble, which can be used for construction purposes. The capacity of the experimental production line is up to 20 t / h.

EXAMPLE 2.

Consider the separation of construction rubble. The task is to obtain a stable quality of crushed stone containing a small amount of weak grains that have a flat shape (flaky grains). The process of pneumatic enrichment was carried out on an experimental setup presented in FIG. During processing, the source material is crushed and classified into machine classes, and crushed stone of class 5-10 and 10-20 mm is used for processing, most often used in road construction, each of which is processed separately. Particles with a size of 5-10 mm are fed to a belt conveyor 1, with a web made of a mesh with a 3 mm cell and a width of 1000 mm moving at a speed of 1.0-2.0 m / s, over which one chamber 3 is installed, with a conical base 4, equal to the width of the conveyor - 1000 mm .. The cylindrical part of the chamber has a diameter of 1500 mm and a height of 1600 mm. The chamber is connected to the gravity precipitation chamber 9 with an upper base diameter of 2800 mm, a lower base of 2000 mm and a height of 3700 mm. Rubble particles with a size of less than 3 mm, which remained in the rubble of class 5-10 due to the impossibility of their complete removal, wake up under the conveyor belt 1, fall on a vibrating trough (it is not shown conventionally in Fig. 1) and are removed from further processing. The air streams 6 and 17 in the separation chamber 3 are selected in such a way that the product 3 has a flat, planar shape, and on the conveyor net 1 there remains a product represented by grains with a shape close to cubic. The capacity of the experimental production line is up to 100 t / h.

Crushed stone of class 10-20 mm is processed on a similar installation, which differs in that the mesh size of the conveyor grid 1 is 5 mm.

EXAMPLE 3.

Consider the separation of household waste. In the process of human life, large volumes of municipal solid waste are generated. They contain both organic waste and valuable materials for recycling: glass, plastics, paper, cardboard, etc. When recycling solid waste, the first stage involves the removal of small impurities with a particle size of 40 mm or less. They are mainly represented by organic waste and cullet, and are sent for further washing. Material larger than 40 mm in size is fed to a shredder with a knife width of 20 mm, in which a flat material is cut into strips 20 mm wide or crushed into particles of the same size. Then, all the material is fed to a belt conveyor 1, with a web made of a mesh with a 10 mm cell, 500 mm wide and moving at a speed of 0.5-1.5 m / s, over which successively two cylindrical chambers 3 with conical chambers are installed bases 4, equal to the width of the conveyor - 500 mm. The cylindrical part of the chamber has a diameter of 1200 mm and a height of 2000 mm. Each of the chambers is connected with its gravitational sedimentation chamber 9 in the form of an inverted truncated cone with a diameter of an upper base of 2400 mm, a lower base of 900 mm and a height of 3200 mm. Each chamber has a design that provides for the formation of two oppositely directed vortices 15 and 17. Particles of raw materials with a size of less than 10 mm wake up under the conveyor net 1 and fall on a vibrating chute (it is not shown conventionally in Fig. 1), which removes product from under the conveyor 1. The air flow in the chambers is selected in such a way that the first chamber releases the product represented by thin materials, such as films, fabrics, paper, plastic from bottles, and in the second chamber, thicker - Gloss, which presented s basically cardboard. The material remaining on the conveyor is represented by cubic-shaped grains, which are received for further processing. The resulting products are then briquetted and used as fuel or raw materials for the chemical industry. The capacity of the experimental production line is up to 4.5 t / h.

Thus, the inventive method allows you to effectively carry out pneumatic separation of particles from various mineral and industrial raw materials, differing in their form.

Claims

Claim

1. Pneumatic method of separating mineral and technogenic raw materials in the form of particles, including placing the processed raw materials on an air-permeable surface, made in the form of a conveyor, passed below the level of the lower base of the separation chamber, in which a volume pseudo-boiling layer is formed by selecting the air flow rate from particles of a given density, into which particles of lower density get into and freely pass through it, and then are transferred from the vertical air stream by an ascending air stream Chambers of gravity sedimentation, characterized in that an additional air stream directed tangentially oriented to the chamber wall is directed to the separation chamber, creating auxiliary vortex flows at the walls and the lower base of the chamber, after which particles of flat, needle-shaped or filamentary shape are picked up by ascending air flow and transfer them to the gravitational deposition chamber, in which they create one or more oppositely directed vortex flows, precipitating particles in the chamber, from where they are then removed.

2. The method according to claim 1, characterized in that the additional tangentially oriented stream of air is fed through a tangential nozzle, which is installed with the possibility of changing its position in the vertical plane.

3. The method according to claim 1, characterized in that the speed of the additional tangentially oriented air jets is selected experimentally for each selected fraction of particles.

4. The method according to claim 1, characterized in that for the simultaneous separation of different fractions of particles of a flat, needle or filamentary form, several separation chambers are set in series, each of which selects individual parameters for the selection of particles of a given shape and size, Each chamber is connected to its own gravity deposition chamber.

5. The method according to claim 1, characterized in that the particles deposited on the walls of the gravitational deposition chamber are removed by the contact method, for example, by mechanical scrapers.

6. The method according to claim 1, characterized in that the particles deposited on the walls of the gravitational deposition chamber are removed by a contactless method, for example, by exposure to an air stream.