SU1747169A1 - Method of concrete aggregate cleaning of lump clay - Google Patents

Abstract

Use: when cleaning granular materials, mainly aggregates for concrete, for example rubble and gravel, from lumpy clay. SUMMARY OF THE INVENTION: The starting material is subjected to mechanical action to give clods of clay a flat (plank) shape and is fed into a hydraulic classifier. Particles with a larger hydraulic size, such as gravel, are deposited in the first discharge chamber along the stream, and coma clay due to a decrease in the hydraulic size of its clods in the second, 5 sludge.

Description

The invention relates to methods for cleaning granular materials, mainly aggregates for concrete, for example rubble and gravel, from coma clay.

There is a known method of washing aggregates for concrete, carried out in various types of washing machines (sink pan, drum machines, vibratory washers, jet washing machines).

The disadvantages of this method include the high energy consumption associated with the need for energy consumption for clay dispersion, low operational reliability, high consumption of wash water and the need to use special equipment to clean it from dispersed clay particles, high specific intensity. Rinsing machines can rinse efficiently

material with a lumpy clay content of not more than 10%.

There are known methods for cleaning aggregates for concrete, based on the difference in physical-mechanical means (characteristics of friction and elasticity) of the materials to be separated, - rials. These methods are implemented in elastic classifiers of various types and vibration classifiers.

The disadvantages of these methods are low separation efficiency and productivity (up to 40 t / h).

The closest to the technical essence of the invention is a method of separating granular materials by hydraulic size in a horizontal flow of separation fluid. Hydraulic size is the speed of free uniform fall (deposition) in an unperturbed medium. The process of deposition of particles of material larger than 1.5 m

VI

VI

Yu

happens in a turbulent mode. For this case, the hydraulic particle size is determined, for example, by the empirical formula of VN Goncharov:

0 33.1

where RT is the density of the particle material; RV is the density of the separating liquid (water);

 - equivalent particle diameter. In a standard horizontal flow of liquid, along with sedimentation, horizontal transport of particles occurs. Particles with the same hydraulic rupture have the same trajectory, then they are deposited on the bottom in the designated zone.

This method is implemented in a chamber hydraulic classifier.

The initial material is loaded into the classifier and the hydraulically sized odes are divided by hydraulic size. At the same time, heavy contaminants fall out along the first along the chamber, the purified material into the second and light sor in the third. Sorted material is discharged through the discharge chamber.

The disadvantage of this method is the low quality of separation of materials, due to the fact that some of the clogging impurities have a hydraulic size that is slightly different from the hydraulic size of the material being cleaned and does not separate from the hydraulic classifier. For this reason, the use of this method for cleaning rubble and gravel from lumpy clay is inefficient.

FIG. The curves of the deposition of particles of gravel and ball clay in a uniform flow with a depth of 6 m, having a constant velocity of V 0.8 m / s, are shown. The calculations were performed for particles with a diameter of 20–40 mm introduced into the flow without an initial velocity,

In addition to density and size, the deposition rate of real particles in a liquid is significantly affected by their shape. Since the gravel being mined is not a homogeneous material and the grains within one fraction differ in three main parameters (density, size and shape), the precipitation curves of gravel and lump clay obtained as a result of laboratory studies under the aforementioned calculation conditions (Fig. ), significantly different from the calculated ones.

The results of laboratory investigations of the process of isolation from graviolwood clay in the hydraulic classifier showed that the poor quality of cleaning is mainly due to the shape of clods of clay and grains. The size of the calculated equivalent diameter d3, included in the formula, for clay clods, which are usually spherical or ovoid, is larger than for particles of gravity of the same size, which for the most part have an irregular shape.

The goal of this technique is to improve the quality of cleaning aggregates for concrete, for example, gravel and rubble, from lumpy clay. This goal is achieved by the fact that the cell according to the method of the source material is transferred to the hydraulic classifier

the horizontal type is subjected to mechanical stress to give the clay a flat shape.

A distinctive feature of the proposed method is that, in a known

the classification method included an additional step of preparing the source material for separation, namely, making the clay flat.

A proposed method for removing aggregates from concrete from clay slag, such as rubble and gravel, is that the raw material is distributed in a monolayer and subjected to mechanical action to give the clod of clay a flat

forms by means of a deforming device located, for example, above a belt conveyor or vibratory feeder. After that, the material is loaded into the hydraulic classifier, in which

it is separated by hydraulic size. At the same time, gravel is deposited in the first chamber along the stream, and - homova clay - in the second. Sorted material is discharged through the discharge chamber.

The method can be implemented, for example, on the device shown schematically in FIG. 3, side view; figure 4 is the same, top view.

The device contains a separating chute 1, to which the receiving box 2 adjoins, separated from the chute by a soothing grill 3. In the lower part of the separating chute are located

discharge chambers 4. The device is equipped with a water supply system 5 and guide plates 6, above which are located a feeder 7, a conveyor belt 8 with a drive 9 and associated with it

deforming device 10 with a drive 11.

The method is carried out as follows.

The source material (gravel or rubble clogged with lumpy clay) of a certain fraction is fed through the feeder 7 by a monolayer to a belt conveyor 8, which transports it under a deforming device 10 rotating around its axis, the outer surface of which is not less than the speed of the conveyor belt. The deforming device is installed above the conveyor belt with a gap corresponding to the size of the material being processed, and provides an elastic effect on the clod of clay with the help of springs or fixed masses.

The deforming device can be made in the form of an elastic roll with a large deformation capacity, produced, for example, from elastic materials. It can also be made of a series of cylindrical elements capable of rotating around its axis and moving independently of one another in the direction towards or away from the conveying surface.

The source material passes between the conveying surface of the conveyor and the deforming device. In this case, the gravel (or crushed stone) does not undergo changes, and the coma is deformed and acquires a flat shape. Then the material enters the separation chute 1 of the hydraulic classifier, where it is divided by hydraulic size. At the same time, particles with a larger hydraulic size, such as gravel, are deposited in the first discharge chamber 4 along the stream, and the clay in the second. Purified material and clogging impurities are discharged through discharge chambers 4.

Advantageously, the proposed method consists in improving the quality of aggregate cleaning for concrete, which is achieved by reducing hydraulic

lump size of clay by deforming, i.e. Give all clods of clay a final flat shape, regardless of their original form. A flat-shaped lump with the same mass with lumps of other forms has the smallest hydraulic size, i.e. deposited in a certain layer of liquid for a longer time. In a horizontal flow of liquid, clump of flat clay will be transferred to the greatest distance.

In addition, the application of the proposed method makes it possible to more fully utilize natural resources (raw material base) in connection with ensuring more complete extraction of the useful product from the material extracted and the possibility of developing contaminated sites of deposits.

The results of the experiments showed that in order to obtain building gravel with inclusions of lumpy clay within 0.25% by mass (requirements of GOST 8268-82), the loss of gravel when cleaning the source material with a content of lumpy clay of 30% was 14% (FIG. .five). The main part of the losses consists of grains of weak rocks, as well as grains of a flat shape, the content of which in the finished product is limited to GOST 8268-82.

In the case of cleaning the gravel from lumpy clay in the hydraulic classifier without first deforming the lumps of clay, all other things being equal, the loss is 91% (Fig. 2).

Claims (1)

Invention Formula A method for removing aggregates for concrete from a clay slab, including feeding the raw material into the hydraulic classifier, separating the material according to hydraulic size and unloading the separation products, characterized in that, in order to improve the quality of cleaning, the raw material is subjected to mechanical action lump of clay flat forms. about 0.5 Editor M. Bandu pa SlM Compiled by E. Kiseleva Tehred M. Morgental Proofreader A.Osaulenko