RU2564212C1 - Method to mix and grind materials - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method is designed for dry and wet grinding of bulk, granular and powdered materials, and also for preparation of mixes. Grinding bodies (3) and ground material (2) are loaded into a rotary working reservoir (1). The layer of the mix (4) of the ground material and grinding bodies is formed under action of centrifugal forces at the inner surface of the working reservoir. The layer of the mix is processed with the help of a fixed or rotary blade. Processing is carried out with a pair of blades. By the first blade (5) from the pair along the direction of rotation of the working reservoir they separate grinding bodies from the layer of the mix, and a flow is formed from them at the angle of γ₁ to the tangent inner surface of the working reservoir. Ground material is sent via through slots and/or holes of the first blade. By the second blade (6) of the necessary length they separate the ground material from the inner surface of the working reservoir, and the flow is formed at the angle γ₂ to the tangent inner surface of the working reservoir of the ground material. Direction of flow motion is set by the angle of rotation φ of the first and second blades relative to each other.

EFFECT: invention increases efficiency of the grinding process and level of dispersity of ground material and mixing, and reduces duration of processing cycle and increase.

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Description

The present invention relates to methods of grinding and mixing using centrifugal methods and is intended for dry and wet grinding of lump, grain and powder materials, as well as for the preparation of mixtures used in various industries.

A known method of grinding (Sidenko PM. Grinding in the chemical industry. Ed. 2nd, revised M., "Chemistry", 1977 - S. 158), in which the crushed material and grinding bodies are fed into a rotating relatively horizontal axial cylindrical or truncated cone-shaped working vessel, where they are pressed against the walls of the working vessel by gravitational forces and, due to friction forces arising between the inner surface of the working vessel and grinding media, as well as the crushed material, are moved to the upper part of the working vessel tanks, where under the influence of gravitational forces break away from the inner surface of the working tank and fall into its lower part.

The disadvantage of this method is that the level of impact grinding effect on the material depends on the mass and height of the grinding media, and the abrasive effect of grinding media occurs at relatively low stresses of normal and shear deformations. All this leads to a significant increase in grinding time (up to several tens of hours) and the emergence of the limiting values of dispersion (fineness) of the crushed material, justified by the kinetic and potential energy of the grinding media.

Of the known methods closest to the claimed is a Method for the preparation of molding sand-clay mixtures. (RF patent No. 2238818 dated June 11, 2003, MKI ⁶ V22C 5/04. BI No. 30 dated October 27, 2004), in which the ingredients are processed in a rotating cylindrical bowl with a rotating rotor with a blade, while the bowl is rotated at a speed that creates pressure in crushed material, equal to 0.14-0.9 of the maximum compressive strength of the crushed material, and the blade relative to the bowl rotate at a speed of 1.5 ... + 1.0 of the speed of rotation of the bowl.

A significant drawback of this method is that grinding and mixing are realized only due to the impact of particles of the crushed material on each other and in the process of collision with the surface of the working tank, while the resulting level of shock and abrasion is insufficient for intensive grinding of durable materials. In addition, the speed of the particles of the ground mass is almost the same at the stages of free flight and collision with the surface of the working capacity, which significantly reduces the level of impact. The influence of these factors leads to a significant increase in grinding time and restrictions on the limiting values of fineness (dispersion) of the obtained crushed materials.

The technical result of the invention is to increase the productivity of the grinding and mixing process, reducing the duration of the processing cycle and increasing the level of dispersion (fineness of grinding) of the crushed material.

The technical result is achieved by the fact that in the method of mixing and grinding materials, in which the grinding bodies and the crushed material are loaded into a rotating working container, where under the action of centrifugal forces they form a layer of the crushed material and grinding bodies on the inner surface of the working container and are processed using a stationary or rotating blades, the processing is carried out by at least one pair of blades, while the first in the direction of rotation of the working capacity of the blade from the pair is separated from the mixture layer release material and grinding media grinding media and form one stream at an angle γ ₁ to a tangent inner surface of the processing container, and the ground material is passed through the through grooves and / or the first blade holes of the pair, and the second spatula desired length separated ground material from the inner surface working capacity and form a flow at an angle γ ₂ to the tangent inner surface of the working capacity of the crushed material, while the direction of flow of the crushed material and grinding media is set at an angle the gate φ of the first and second blades relative to each other. The flow of grinding media after it leaves the blade is directed to a layer of crushed material formed on the inner surface of the working vessel after the crushed material leaves the second blade of the pair. The flow of crushed material and the flow of grinding media after they leave the vanes are guided so that the intersection of the flows is inside the working tank. To direct the flow of grinding media after it leaves the first blade to the flow of crushed material after it leaves the second blade, the angle φ of the relative position of the blades, and / or the angle γ ₁ and / or the angle γ _{2 of} rotation of the blades are changed. The flow of grinding media after it leaves the first blade is directed to the flow of crushed material moving along the second blade of the pair.

To direct the flow of grinding media after it leaves the first blade, to the flow of crushed material moving along the second blade, change the angle φ.

The crushed material passing through the through grooves and / or holes of the blade is displaced along the axis of the working container.

The essence of the proposed method is illustrated by drawings:

in FIG. 1 shows a motion diagram of the milled material and grinding bodies of the working vessel;

in FIG. 2 is a view A of the front surface of the blade of FIG. one;

in FIG. 3 shows a cross section BB of the blade of FIG. 2;

FIG. 4 - diagram of the intersection of flows within the working capacity;

FIG. 5 is a flow chart for mixing flow in free flight.

The method is as follows.

In a rotating working container 1, which can be made in the form of a cylindrical, conical or cylindrical-conical bowl (Fig. 1), crushed material 2 and grinding bodies 3 are loaded. During loading, crushed material 2 and grinding bodies 3 are partially mixed, forming a mixture of 4 crushed material 2 and grinding media 3. Under the action of centrifugal forces, mixture 4 of the crushed material 2 and grinding media 3 is pressed against the inner surface of the working container 1. Due to the friction forces between the inner surface of the working container 1, the mixture 4 is dispersed up to the rotation speed of the working tank 1.

When combined with the working capacity 1, the crushed material 2 and the grinding bodies 3 in the mixture layer 4 are subjected to centrifugal forces, the magnitude of which depends on the speed of the working vessel 1 and the thickness of the mixture layer 4 and can reach values comparable with the mechanical strength of the crushed material 2 Thus, the layer of the mixture 4 is compacted, and the crushed material 2 is partially destroyed under the action of normal stresses created in the layer of the mixture 4 by centrifugal forces. After that, from the layer of the mixture 4, located on the inner surface of the working tank 1, the blade 5 is first separated in the direction of rotation of the working tank 1, which has through slots 7 and (or) holes 8 (Fig. 2), grinding bodies 3. Since the width the through grooves 7 and (or) the holes 8 are smaller than the smallest size of the grinding bodies 3, they move along the front surface of the blade 5 and, upon leaving the blade 5, form a flow of grinding bodies 3.

When this crushed material 2 passes through the through grooves 7 and (or) holes 8 in the blade 5 and falls on the inner surface of the working container 1. After that, the crushed material 2 is separated by a blade 6 from the inner surface of the working container 1. The crushed material 2 moves along the front surface blades 6 and when leaving the blades 6 forms a flow of crushed material 2.

Orienting (turning) the blades 5 and 6 relative to each other, change the intersection of the flows of grinding bodies 3 and the crushed material 2 after they leave the blades 5 and 6. Change the direction of flows of grinding bodies 3 and the crushed material 2 after they leave the blades 5 and 5, respectively 6 is carried out by changing the angle of inclination of the blade γ ₁ and γ ₂ The angle of inclination γ _{1 of the} blade 5 is measured as the angle between the tangent drawn to the front surface of the blade 5 at point B (Fig. 1) of the vanishing flow of grinding media 3 and tangent to the inner surface of the working container 1 in point G (Fig. 1) of its intersection with the tangent to the front surface of the blade 5. The angle of inclination γ _{2 of the} blade 6 is measured as the angle between the tangent drawn to the front surface of the blade 6 at point E (Fig. 1) the flow of grinding media 3, and tangent to the inner surface of the working tank 1 at point D (Fig. 1) of its intersection with the tangent to the front surface of the blade 6. In addition, you can change the direction of flow of the crushed material 2 and grinding bodies 3 after they leave the blades 5 and 6 by changing angle φ between radius vectors data from the center of rotation of the working vessel 1 to the points of intersection T and D of the blades 5 and 6 tangent to the front surface of the blades drawn at the vanishing point of the flows of the crushed material 2 and grinding media 3 to the inner surface of the working vessel 1 of their intersection with the tangents to the front surface of the blades 5 and 6. In addition, by changing the length of the front surface of the blade 6 along the flow direction of the crushed material 2, it is possible to form the intersection of the flows of the crushed material 2 and the grinding media 3 on the surface of the blade 6 (FIG. 5).

In order to obtain a different degree of grinding, the following options are possible: the flow of grinding bodies 3 after it leaves the blade 5 is directed to the layer of material 2 that is formed on the inner surface of the working vessel after it leaves the blade 6 (Fig. 1); the flow of crushed material 2 and the flow of grinding media 3 after they leave the blades 5 and 6 are directed so that the intersection of the flows is inside the working tank (Fig. 4); the flow of grinding media 3 is directed to the flow of crushed material 2, moving along the blade 6 (Fig. 5).

The implementation of the above options for the interaction of the flows of grinding media 3 and the crushed material 2 can be performed both at a fixed angle φ of the relative position of the blades 5 and 6, and with its continuous or periodic change in the direction of decreasing or increasing the angle φ.

In addition, the processing of materials can be carried out both at a fixed angle ^γ _{1 of the} direction of motion of the grinding media 3, and with its periodic or continuous change in the direction of decrease or increase. Processing of materials can be carried out both at a fixed angle γ _{2 of the} direction of movement of the grinding bodies 3, and with its periodic or continuous change in the direction of decrease or increase.

The implementation of the third processing variant shown in Fig. 5 can be carried out not only by changing the angle φ or γ ₁ , but also by changing the length in the flow direction of the blade 6.

The crushed material 2 under the impact of the flow of grinding media 3 is intensively crushed under compression by centrifugal forces. In addition, when the layer of mixture 4 is divided into grinding bodies 3 and crushed material 2, intensive mixing of the crushed material 2 occurs if it consists of several (two or more ingredients). To increase the intensity of mixing of the crushed material 2 and reduce the phenomenon of overgrinding using through grooves 7, or holes 8, or other structural elements on the blade 5, the crushed material 2, passing through the through grooves 7 or holes 8, is displaced along the axis of rotation of the working vessel 1, for example , due to the inclination of the side walls 9 of the through grooves 7 or holes 8 (Fig. 3). In addition, the displacement of the crushed material 2 along the axis of the working tank 1 allows you to remove the material from the zone of intensive processing and move it to the unloading zone. Processing of the material can be carried out in a rotating working container 1 by stationary or rotating blades 5 and 6. The direction of rotation of the blades 5 and 6 may coincide with the direction of rotation of the working container 1, or the working capacity 1 and the blades 5 and 6 can rotate in different directions. The choice of direction and speed of rotation of the blades 5 and 6 depends on the properties of the crushed material 2. To increase the intensity of grinding and mixing, the processing of the material inside the working container 1 can be carried out with two or more pairs of blades 5 and 6, distributed both around the circumference of the working container 1, and along its axis. The principle of operation of each of these blades is similar to the principle of operation of blades 5 and 6 described above.

This method of mixing and grinding materials allows the processing of the crushed material 2 at a high level of compressive stresses arising in the layer of the mixture 4 and the layer of crushed material 2 under the action of centrifugal forces. In addition, the regulation of the rotational speed of the working tank 1, the frequency and direction of rotation of the blades 5 and 6, as well as their relative position relative to each other, allows you to adjust the level of impact of the grinding bodies 3 on the layer of crushed material 2. This allows you to grind material with various physical and mechanical properties , sharply reducing the level of overgrinding due to the selection of processing modes.

Reducing the processing time of grinding and mixing when using this method occurs due to an increase in the intensity of the impact on the crushed material 2, which is in a compressed state, as well as due to the repeated repetition of single processing cycles, the withdrawal of the crushed material 2 from the zone of intensive exposure and additional abrasion on the crushed material 2 during its joint movement with the grinding bodies 3 along the blade 5 and 6.

Experimental studies have shown a decrease in noise during grinding and mixing in comparison with traditional mills, as well as a significant reduction in wear on the inner surface of the working vessel 1.

Claims (7)

1. A method of mixing and grinding materials, in which the grinding bodies and the crushed material are loaded into a rotating working container, where they, under the action of centrifugal forces, form a layer of crushed material and grinding bodies on the inner surface of the working container and are processed using a fixed or rotating blade, characterized in that the treatment is carried out by at least one pair of blades, while the first in the direction of rotation of the working capacity of the blade from the pair is separated from the layer of the mixture of crushed material and ground grinding bodies and form a flow from them at an angle γ ₁ to the tangent to the inner surface of the working container, and the crushed material is passed through the through grooves and / or holes of the first blade from the pair, and the crushed material is separated from the inner surface of the working container with a second blade of the required length and form a flow at an angle γ ₂ to the tangent inner surface of the working capacity of the crushed material, while the direction of motion of the flows of the crushed material and grinding media is set by the rotation angle φ of the first and second oh blades relative to each other. 2. The method according to claim 1, characterized in that the flow of grinding media after it leaves the blade is directed to a layer of material to be ground, formed on the inner surface of the working vessel after the material to be ground from the second blade of the pair. 3. The method according to claim 1, characterized in that the flow of ground material and the flow of grinding media after they leave the vanes are guided so that the intersection of the flows is inside the working tank. 4. The method according to claim 2 or 3, characterized in that for directing the flow of grinding media after it leaves the first blade to the flow of crushed material after it leaves the second blade, change the angle φ of the relative position of the blades, and / or the angle γ _1, and / or angle γ ₂ rotation of the blades. 5. The method according to claim 1, characterized in that the flow of grinding media after it leaves the first blade is directed to the flow of crushed material moving along the second blade of the pair. 6. The method according to claim 5, characterized in that the angle φ is changed to direct the flow of grinding media after it leaves the first blade to the flow of ground material moving along the second blade. 7. The method according to claim 1, characterized in that the crushed material passing through the through grooves and / or holes of the blade is displaced along the axis of the working container.

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