SU1632520A1 - Method for separating bulk materials - Google Patents

Abstract

This invention relates to the separation of solid, for example, bulk materials (SM) in the mining, metallurgical, chemical and other industrial sectors. The goal is to intensify the separation process. For this, the SM is fed to a rotating drum (B). At the same time, rotation B is preset in a mode determined by the dependence B 0.8 °, where B Rx xtd / g is a dimensionless criterion that takes into account the complex effect of all forces on the body in rotating B R - radius B, m; WITH - angular velocity B, rad / s; g is the acceleration of free fall, m / s2, d / D is the relative size of the narrow boundary fraction, which delimits the mixture of CM into two classes - plus D and minus fb; d is the particle diameter of the boundary fraction, m; D is the diameter of maximum particles, m. With this rotation B, the material is stratified by size with the concentration of one of the excreted SM fractions in the lower part B in the center of the gravity of the displaced CM. The required angular velocity (x) B and the axis of the discharge chute are shifted relative to the vertical diameter B along its rotation by the angle B of the slope SM at the top of the load, and from B to its center along the radius K defined by the above formula. In this case, the fraction concentrated in the center of gravity of the displaced CM during rotation B is removed by means of the discharge chute by means of its alignment with the concentration region of this fraction. 3 il. (O fe: o u u1 nd p

Description

The invention relates to methods for separating solid, for example, bulk materials, and is intended for use in the mining, metallurgical, chemical industry, in enterprises producing construction materials and agriculture.

The purpose of the invention is to intensify the separation process.

FIG. 1 shows a separator for carrying out the proposed method, a longitudinal section; in fig. 2 is a scheme for determining the center of gravity (kidney) of the material being transferred; in fig. 3 is a plot of B 0.8.

The method of separation of bulk materials includes the supply of material into a rotating drum, pouring material in a waterfall mode, separation

size of the material with the concentration of one of the separated fractions in the lower part of the drum in the center of the gravity of the material being moved and the separation of the fraction concentrated in the center of the gravity of the material being moved by combining the axis of the loading trough with their concentration area. Pre-set the rotation of the drum mode

B 0.8 # 3, (1)

RCO where; B is a dimensionless criterion

g

R - CO g

 TO

D

taking into account the complex effect of all forces on the body in a rotating drum;

radius of the drum, m; angular velocity of the drum, rad / s; acceleration of free fall, m / s;

the relative size of the narrow boundary fraction delimiting the mixture into two classes — plus-D and minus d — the diameter of the particles of the boundary fraction, m; D - diameter of maximum

particles of the mixture, m;

and the axis of the discharge chute is displaced relative to the vertical diameter of the drum along its rotation by an angle 3 3 and the angle of repose of the material, equal to the angle of elevation of the center of the loading bar, from the drum shell by an amount

3

four

COR

2jh (). SinCtf) 1 R4 R cosp

, (2)

where n

the thickness of the layer of the material being moved (arrow of the loading segment), m;

& Ј, is the angle of slope of the material in the upper part of the load, equal to the angle of elevation of the center of the loading bar; D is the angle of internal friction of bulk material.

The h segment arrow depends on the drum loading level. With an optimal degree of loading Cj 0.5, the arrow of the segment is equal to the radius of the drum. The method allows only one change in the angular velocity of the drum

0

five

0

five

0

five

0

five

0

five

and by the corresponding displacement of the axis of the discharge chute relative to the drum, it is easy and precise to regulate the separation of the most diverse bulk material into two specified size classes, i.e. allows you to expand the scope of application of the method and the regulation of the particle size distribution of the loose mixture released during separation.

The method is carried out in a separator consisting of a driving drum 1, a fixed disk 2, rigidly fastened to the loading chute 3 and installed in the drum cavity with a gap and in the lower part, a disk 4 having an eccentric hole 5 and installed with the possibility of rotation in the end parts of the drum, in the hole 5 rotatably mounted second disk 6 with an eccentric hole 7, in which the discharge chute 8 is installed in the form of a hollow cylinder with a possibility of rotation and translational axial movement cores with screw blades 9 in the internal cavity, rigidly fastened to the walls of the cylinder. The device is also equipped with chutes 10 and 11 under the chute 8 and a device 12 for transferring the separated fractions 13 and 14 to the process stream.

I

For turning the disk 4, a worm gear is provided (worm to 15, worm crown 16). The drum 1 is installed in supporting rollers 18 by means of a bandage 17. Clamping screws 19 are provided for fixing the disk 6 in the desired position relative to the disk 4. A pneumatic or hydraulic cylinder 21 is mounted on the nozzle 20 of the disk 6, the stem 22 of which is pivotally connected to the ring 23 installed in the annular a groove 24 on the surface of the chute 8. On the platform 25 of the ring 23, an actuator 26 is mounted to drive the chute 8 into rotation by means of toothed or friction wheels 27 and 28. The first one is mounted on the drive shaft 26, the second is fixed on the discharge chute 8.

The upward flow of material (making a circular motion with the drum) is indicated by the position 29, the descending (pouring down) is indicated by the position 30. The direction of movement of the ba

Rabana and material flows are indicated by arrows.

The method is carried out as follows.

In the cavity between the discs 2, 4 and 6 of the rotating drum 1, along the loading chute 3, the separation material bulk flow is continuously supplied, which in a layer (stream 29) lies on the surface of the drum and rises up with it until the centrifugal force acting on the particle of the mixture, and the radial component of the force of gravity, directed from the point in question to the axis of rotation of the drum. In this case, the particles detach from the surface of the drum or layer of the mixture and fall down, overflow and interact with one another. Since the particles of the mixture located at different distances from the axis of rotation have different initial velocities at the time of opening, the upper layers of the pouring mixture (flow 30 have a greater speed and lower speeds, i.e., the movement of the mixture is vortex. In a vortex When particles interact, particles of a certain size (fraction) move to places where the mixture speed is minimal, and accumulate there, forming a so-called kidney, while the center of the kidney stays in place all the time - on the border between the ascending 29 and the descending 30 streams. M The material rolls around the inner surface of the drum, rotating at the same time around the kidney.

As shown by theoretical and experimental studies, the center of the kidney is located on the radius of the drum, rotated from the bottom of the vertical diameter in the direction of rotation of the drum at an angle L of the center of the loading bar, at a distance of

0

0

five

delimiting these two classes (boundary fraction), with a known value of criterion B, can be determined according to a diagram (Fig. 3) constructed from experimental data. FIG. The 3rd fraction of the mixture is indicated by its relative size o At a 2 Xip (where oCp is the average relative particle size of the mixture) particles of class plus are concentrated in the kidney (in the diagram, the shaded area is from + Ј to 1), with (PCp = particles of class minus a ( on the diagram, it is shaded- 5 for the zone from zero to –i.) When the particle size of the mixture is uniformly distributed throughout the volume, there is no separation.

Thus, to separate the bulk material that is continuously fed into the drum into two classes of particle size: + $ n - o, the dimensionless criterion B, characterizing the mode of motion, is determined by the relation (1), and the required angular value is determined from it with a known drum radius R drum speed according to the formula

(3)

After installing the chute 8 into the desired position, the drum is rotated at a speed of CO, and to evacuate the kidney material, the axis of the discharge chute is shifted relative to the drum: from the bottom of the vertical diameter - during the rotation of the drum at an angle | i lifting the center of loading bar, from the shell drum - by the value of K, determined by the formula (2).

The fraction concentrated in the kidney, when the drum rotates, is removed by the discharge chute 8 and enters the chute 10, the rest of the material through the gap and is poured out of the drum cavity into the chute 11.

from the shell of the drum.

Depending on the speed of rotation of the drum, i.e. depending on the dimensionless criterion B, large or small particles of the mixture are concentrated in the kidney, and the mixture is divided into two classes by particle size — one class is concentrated in the kidney and the other around it. Narrow fractions

To install the chute 8 into the desired position, turn the screw to 15 in the required direction, while turning the screw 16 with the disk 4 at a given angle. After holding the disk 4, the clamping screws 19 are turned to the right position, the disk 6 is turned in the slots of the disk 4 at the desired angle, while the center of the gutter 8 coincides with the center of the kidney. By tightening the clamping screws 19, the disk 6 is fixed in the required position, and

therefore, the center of the discharge gutter 8.

Subsequently, the drive 26 is turned on, which, through the wheels 27 and 28, causes the chute 8 to rotate. Then the cylinder 21 is put into operation, which by means of the rod 22 pivotally connected to the circular ring 23 and the annular groove 24 causes the chute 8 to be in translational direction. along the axis of movement, according to a given program, periodically entering the chute 8 into the cavity of the drum 1 and its output from the cavity of the drum 1.

With a properly selected transport speed along the discharge chute, the number of particles newly concentrated in the kidney is equal to the number of particles that have passed into the discharge chute, and thus, the separation process is continuous.

If it is necessary to divide the granular mixture into two other classes, the ratio of (1) determines the new value of the criterion B, and the ratio of (3) gives the new value of the angular velocity of the drum; with which chute 8 is shifted to a new position.

I

Example 1. Bulk mixture - cast iron shot for shot-blasting machines, particle size of the mixture: diameter of maximum particles D 3 mm, diameter of minimum particles dMV (H 0.25 mm. Drum radius R 0.15 m. Angle of lifting center of cast iron casting rod fraction when the drum rotates (3 69, internal friction angle O 40 °. Drum loading degree ($ 0.5, loading segment arrow h R 0.15 m. The mixture should be divided into two classes: + 2 mm and - 2 mm (d 2 mm).

In accordance with the initial data, the relative size of the boundary fraction is determined.

I

d

D

 0.67.

The desired rotational state of drum B 0.8 is determined (P 0.24.

Determine the angular velocity of the drum

YU

Be 0,24-9,81Q ,,

S -1 ---- 1- 3.96 rad / s,

which corresponds to the drum rotation frequency of 37.8 rpm.

P

50

5 o

§

0

five

The coordinate K of the center of the kidney is determined to be 0.088 m. A chute is installed according to the values of the coordinates p 69 ° and K 0.088 m.

The drum cavity is filled with bulk material to be separated to obtain a given loading degree (in example 1 to (0 0.5 or h R 0.15 m).

The drum is rotated at an angular velocity of 3.96 rad / s and simultaneously actuates the mechanisms for rotating and reciprocating the discharge chute. The amount of bulk material fed into the drum (automatically using a separator automation system) is maintained equal to the total number of fractions removed from the drum through the discharge chute and the gap a.

Since the relative size of the boundary fraction I

 D + d 3 + 0 25 And - 0.67 Ts -552TZ

 0.584,

then particles of class +2 are concentrated in the kidney and are removed through the discharge chute, i.e. particles with a diameter of 2-3 mm. The remaining material (0.25-2.0 mm) is removed through the gap a.

EXAMPLE 2. The initial data are the same as in Example 1. The mixture must be divided into two classes: + 1 mm m - 1 mm (d 1 mm).

In accordance with the initial data, in the order of example 1, Ј 0.335 is determined; B 0.03; “1.4 rad / s (p 13.75 rpm), K 0.128 m. A chute is installed according to the coordinates of ft 69 ° and K 0.128 m.

The operations of Example 1 are then repeated with the difference that the drum is driven into rotation with an angular velocity of Q 1.4 rad / s. Since the relative size of the boundary fraction} is 0.335 fljn 0.584, particles of class 1 are concentrated in the kidney and are removed through the discharge chute, i.e. particles with a diameter of 0.25 - 1.0 mm. The remaining material (1-3 mm) is removed through the gap a.

The method allows to separate loose mixtures of different mineral and particle size distribution with particles of various sizes and shapes on the same apparatus.

regulate the particle size distribution of the separation product. The implementation of the invention expands the technological capabilities of industries related to the processing of bulk materials.

Claims (1)

Invention Formula A method for separating bulk materials, which includes feeding the material into a rotating drum, pouring material into a waterfall mode, stratifying the material with a concentration of one of the separated fractions in the lower part of the drum in the center of the gravity of the material being transferred, - the material, by combining the axis of the discharge chute with the area of their concentration, characterized in that, in order to intensify the separation process, I pre-set the drum rotation mode is determined depending on emom B 0.8G R B - dimensionless criteria taking into account the complex effect of all forces on the body in a rotating drum; 12 o R with g and radius of the drum, m; drum speed, rad / s; acceleration of free fall, m / s4; the relative size of the narrow boundary fraction delimiting the mixture into two classes - plus O D and minus D; particle diameter of the boundary fraction, m; diameter of maximum particles, m, and the axis of the discharge chute is shifted relative to the vertical diameter of the drum along its rotation by the angle of slope of the material in the upper part of the load, and from the drum to its center along the radius by D Ur 2gJҐ (2-b). / 8W R cosp m where h is the layer thickness of the material being moved, m; Od - the angle of repose of the material in the upper part of the load, m; O - angle of internal friction rash of what material, m 27 0.2 Ws OM 0.8 LFO, № Fig.Z Compiled by O. Palenova Editor I. Shulla Tehred l. Serdyukov and Proofreader M.Sharoshi Order 573 Circulation 368 Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 4/5 h, Moscow, Zh-35, Raushsk nab. 113035 Ws