CN108405135B - A kind of tailings sand high-efficiency desliming and powder removal and particle shape optimization method and device - Google Patents

Abstract

A method and device for efficient desliming and powder removal and particle shape optimization of tailings sand relate to shaping, desliming and powder removal of tailing sand, and solve the problem that the current tailing sand cannot be effectively utilized, including particle shape optimization, desliming and powder removal processes. Specifically, the tailings sand firstly disperses the particle groups and agglomerated mud balls in the tailings sand and reshapes the local contour of the sand particles by hitting iron, iron hitting stone, and hitting stone. The particles are classified and separated to realize the separation of muddy matter, stone powder and sand particles. The gas-solid fluid containing mud powder and fine stone powder is used to realize gas-solid separation and fine powder recovery through the dust removal system, so as to realize the full utilization of tailings sand and protect the environment.

Description

Efficient mud and powder removing and particle shape optimizing method and device for tailing sand

Technical Field

The invention relates to shaping, mud and powder removal of tailing sand, in particular to a method and a device for efficiently removing mud and powder and optimizing grain shape of tailing sand.

Background

As one of the main components of concrete, the sand plays roles of filling and deformation resistance in concrete products, can improve the compactness, mechanical stability and durability of the concrete, and has great influence on the quality of concrete engineering. The related data show that in 2016, the total production and sales of the building sand in China are about 150 hundred million tons, and the total production of the sand is about 70 hundred million tons.

The sand mainly comprises natural sand and machine-made sand, the quantity of construction engineering in China is huge, and the natural sand mainly comprises river sand, sea sand and plain underground egg sand. Through high-strength mining for nearly 40 years, high-quality natural sand resources are gradually exhausted. The exploitation of natural sand has great influence on the ecology of river channels and soil, the governing and recovering period of the natural sand is hundreds of years, and the natural sand can hardly recover the ecological level before exploitation. The sea sand resource amount is large, but the concrete structure is seriously corroded by the sea sand due to the over standard of chloride ions, and the sea sand has no utilization value in the current technical level. The exploitation of large-scale natural sand also causes various safety accidents and frequent quality accidents, and therefore, the western developed countries have successively compressed the exploitation scale of the natural sand as early as the last century. In recent years, the limited mining and forbidden mining strength of natural sands in internal rivers such as Yangtze river, Minjiang river, Ganjiang river and the like and coastal rivers is gradually increased in China. At present, the machine-made sand in China is mainly coarse sand, and the large-scale production technology of the machine-made sand is not mature or the production cost is too high. Therefore, in actual engineering utilization in China, machine-made coarse sand is mainly matched with natural fine sand with high mud and powder content, and product quality fluctuation is large.

The tailing sand is a byproduct of crushed stone produced by a production machine, and cannot effectively replace natural sand due to factors such as high mud content, unreasonable gradation, poor particle shape and the like. According to statistics, the annual tailing sand produced in the middle-aged mining of building stones in China is about 30 hundred million tons, wherein the east region is partially flushed by water to form machine-made coarse sand, and the machine-made coarse sand partially replaces natural sand; the tailing sand in the midwestern region is limited in utilization approach due to water shortage, immature dry-method desilting technology and the like, and is mainly discharged into the natural environment. Therefore, the development of the machine-made sand technology and complete machine-made sand equipment for producing the tailing sand to replace natural sand can solve the problem that the current tailing sand cannot be effectively utilized and can replace the natural sand, thereby achieving the aim of protecting the environment. Meanwhile, the total quantity of the building sand in China is large, and the large-scale production of high-quality machine-made sand by using tailing sand is also the development trend of the building sandstone industry in China.

What is primarily solved by using the tailing sand is how to remove mud and stone powder in the tailing sand, reduce the water content in the tailing sand and locally shape sand in the tailing sand. At present, a powder concentrator in the cement industry is mainly used for a dry-method mechanism sand desliming and powder removing device, wherein the water content of raw materials is generally less than 1 percent, the content proportion of fine powder with the particle size of less than 0.075mm is generally more than 60 percent, and meanwhile, the requirements on wear resistance are low and no shaping requirements are met due to the small particle size and weak abrasiveness of the raw material particles. Special dry-process sand, silt and powder removing devices have also been disclosed. For example, patent CN201420347549.3 discloses a pneumatic sand screening and powder removing device for artificial mechanical sand making, which is characterized by comprising: a dynamic powder concentrator and a static powder concentrator; the dynamic powder concentrator is directly positioned on a box body of the static powder concentrator through flange connection; the dynamic powder concentrator comprises: the device comprises a transmission device, a rotor, a fixed guide vane and a first shell; the fixed guide vanes are annularly fixed on the first shell by a plurality of pieces, and the rotor is suspended and arranged through a bearing seat in the box body; the rotor extends out of the transmission shaft from the upper surface of the first shell, and the transmission shaft is connected with a transmission device fixed above the first shell through a coupler; the static powder concentrator comprises: the second shell, the step plate, the flow guide air grid, the granularity control adjusting mechanism and the turning plate air locking valve; the step plate is fixed inside the second shell, and a flow guide air grid is arranged at the right air inlet of the step plate; a granularity control adjusting mechanism is arranged at the lowest part of the step plate; and a flap airlock valve is arranged at the lowest outlet of the second shell. Patent CN200920073699.9 proposes a powder removing device for machine-made sand, which comprises a dust removing system, an air blowing system and an air suction and dust collection system, wherein the dust removing system is provided with two rows of bulk material grid plates in a hollow rectangular shell, and a feeding device and a blanking device are respectively arranged above and below the bulk material grid plates; one side of the dust removal system is connected with an air pipe of a blower through an air regulating valve, the other side of the dust removal system is communicated with an air pipe of a draught fan through an air regulating valve, and the other end of the air pipe of the draught fan is connected with a cyclone dust collector; an air inlet cover is arranged at the communication position of the air pipe of the blower and the dust removal system; and an air outlet cover is arranged at the communication position of the air pipe of the induced draft fan and the dust removal system. Patent CN201710557326.8 discloses an automatic powder-removing sand making machine, which comprises a shell, a bracket, a feed hopper and a rotor assembly, wherein the shell is arranged on the bracket, the rotor assembly comprises a main shaft, a shaft sleeve, a material throwing rotor and a motor, the main shaft is arranged on the shaft sleeve, the shaft sleeve is arranged in the center inside the shell, the material throwing rotor is arranged on the upper end of the main shaft, the lower end of the main shaft is provided with a belt wheel, the motor is positioned outside the shell and arranged on the bracket, the motor is connected with the lower end of the main shaft through the belt wheel and the belt and provided with a belt wheel, the inner wall of the upper part of the shell is provided with an anti-abrasion lining plate, the anti-abrasion lining plate corresponds to the material throwing rotor, the inner wall of the middle part of the shell is provided with a middle anti-abrasion lining plate, the lower part of the shell is an aggregate cone, the feed hopper is positioned at the top of the shell, and, the dress is worn to the draft hood in the outside of main shaft, the last port of draft hood is located the below of fan blade, the casing side is equipped with the air outlet, and cyclone includes barrel, lower cone and air inlet spiral duct, and lower cone sets up the lower extreme at the barrel, is equipped with the air-supply line on the side of barrel, and air inlet spiral duct sets up on the inner wall of barrel, and the air intake of air inlet spiral duct communicates with each other with the air-supply line of barrel side, the air-supply line of barrel side with the casing side is equipped with the air outlet and communicates with each other, and the air outlet of air inlet spiral duct is located the top of lower cone, and the side of barrel is equipped with out the tuber pipe, and the export that should go out the tuber pipe passes. The comprehensive expression of the above patents is as follows: 1. the sand grains are deslimed and pulverized by a static scattering method and a pneumatic separation method; 2. the static scattering method is adopted to realize the mud removal and the powder removal of the machine-made sand, and the recovery particle size is controlled by a dynamic powder concentrator; 3. based on cement trade rotor formula selection powder machine, do not have between rotating cage and the casing inner wall to consider specially including cutting and the runner design of mud powder waste gas stream and sand grain stream according to mud powder and sand grain characteristics, simultaneously, do not carry out special design to sand grain plastic function, do not also carry out rotor blade abrasionproof according to the strong wearability of sand grain and decrease the design.

Therefore, in the prior art of dry-method sand making of tailings sand in China, an integrated method design and a corresponding device are still lacking, wherein the integrated method design and the corresponding device have the advantages that tailings sand is efficiently scattered, sand and mud powder can be repeatedly and dynamically cut and separated for many times, a mud powder-containing waste gas flow and a sand flow special flow passage according to the characteristics of the mud powder and the sand powder are arranged, and the sand is shaped when the tailings sand is subjected to mud removal and powder removal.

Disclosure of Invention

The invention aims to provide a method and a device for efficiently removing mud and powder from tailing sand and optimizing the particle shape.

The technical scheme adopted by the invention for solving the technical problems is as follows: the method is characterized in that the adopted raw materials are mainly tailing sand, wherein the water content of the tailing sand is less than 4%, the tailing sand also contains mud powder, fine stone powder and mud balls, the total content of the mud powder and the fine stone powder is less than 15%, the particle size is less than 0.075mm, the content of the mud balls is less than 5%, and the particle size is more than 0.075 mm; the method specifically comprises the following steps:

step 1: grain shape optimization

1) Pouring the tailing sand into a spreading disc through a feeding hole, centrifugally spreading the tailing sand out at a linear speed of not less than 10m/s by the spreading disc rotating at a high speed, splashing the tailing sand onto a counterattack plate covering the periphery of the spreading disc under the action of centrifugal force, and scattering mud balls, agglomerated mud sand and fine stone powder through collision;

2) the sand particles rebounded by the impact plate are impacted on the impact plate with the rotating speed not lower than 150 revolutions per minute below the spreading disc again at a high speed, so that the scattering of mud balls, agglomerated mud sand and fine stone powder is further realized;

3) the sand grains fly to the impact plate under the impact of the rotating impact plate collide with the sand grains rebounded from the impact plate, so that the scattering of mud balls, agglomerated mud sand and fine stone powder is further realized;

4) in the processes of 1, 2 and 3, more than 90% of mud balls larger than 0.075mm are broken into powder smaller than 0.075mm, sand grains, a fixed counterattack plate, a high-speed rotating attack plate and a sand grain group in high-speed flight realize local contour shaping through stone iron, stone stones and iron stones, and the sand grains are more mellow;

step 2: removing mud and powder

1) An air inlet is tangentially formed in the lower part of the cylinder, in the process of the step 1, air flow is blown into the rotating cage from bottom to top, flows to a gap between the rotating cage impact plate and a counterattack plate fixed outside the rotating cage under the action of the centrifugal force of the rotating cage to form high-pressure air flow, and on the basis of the gravity separation principle, sand, mud and stone powder are classified and separated in the processes of 1), 2) and 3), wherein the separation effect of mud powder and fine stone powder smaller than 0.075mm is not lower than 85%;

2) high-pressure air containing mud powder flows in and out of the barrel tangentially through the air duct and enters the dust remover system to realize gas-solid separation, the mud powder enters a special mud powder bin, and sand grains in the barrel directly enter a sand bin at the lower part of the barrel due to dead weight.

A device used in a tailing sand efficient mud and powder removing and grain shape optimizing method is characterized by comprising a barrel, a sand bin, a mud powder bin, a cyclone dust collector, an impact plate and a counterattack plate, wherein a feed inlet is formed in the middle of the upper end of the barrel, a discharge outlet is formed in the lower end of the barrel, and the sand bin is connected to the lower portion of the discharge outlet; a rotating cage main shaft is arranged in the upper part of the interior of the barrel body along the central axis in the vertical direction, a circular spreading disc is fixed at the upper end of the main shaft, a plurality of impact plates are fixed at the lower part of the spreading disc around the main shaft in an annular shape, and an annular counterattack plate is also fixed between the inner wall of the barrel body and the rotating cage from top to bottom; a tangential air inlet is arranged on the cylinder wall below the cylinder body and above the sand bin, and an air duct is arranged outside the cylinder wall and connected with the air inlet; the outer side of the cylinder is provided with a dust remover connected with the tangential air outlet channel at the periphery of the upper part of the cylinder.

In order to improve the centrifugal acceleration effect of the rotating cage on the inlet air, the included angle between the impact plate and the circumferential tangential direction of the rotating cage is lower than 90 degrees; the impact plates are arranged in a multilayer manner from top to bottom, the diameters of the impact plates are in a gradient from small to large, and the number of layers is not less than 2; the impact plate is a strip-shaped thickened plate, the upper narrow edge and the lower narrow edge of the impact plate are movably fixed on the rotating cage, so that the impact plate can be detached and turned 180 degrees to be fixed on the rotating cage when the working surface is worn to the extent that the efficiency of mud and powder removal cannot be met, and the reverse side of the impact plate becomes the working surface.

The counterattack plates are arranged by supporting the revolving cage on the cylinder body, are annular polyhedrons, are provided with at least 2 layers of counterattack plate layers with the diameters from small to large from top to bottom, are nested with each other in the vertical direction of each layer of counterattack plate layer through the diameter difference, reserve a longitudinal air duct from bottom to top, are plates, surround and form a layer of polyhedron by taking the revolving cage as the center, and are an upper layer of polyhedron and a lower layer of polyhedron, wherein the upper layer of polyhedron has a small diameter, the lower layer of polyhedron has a large diameter, the upper layer of polyhedron and the lower layer of polyhedron are partially overlapped, a space formed by the diameter difference of the two polyhedrons is the air duct, and the ventilation capability of the air duct ensures that the mud-; the high abrasiveness of adaptation sand grain improves the rate of utilization of reaction plate, and the reaction plate passes through the horizontal stand to be fixed on the barrel inner wall, and the reaction plate adopts the fixed mode of dismantling with the horizontal stand, and when the working face of reaction plate worn out and can not satisfy desilting gumming efficiency, pull down, overturn 180 and pass through supporting beam once more and fix to the section of thick bamboo wall, the reverse side of reaction plate becomes the working face.

The invention has the beneficial effects that: the method is used for dynamically scattering mud balls, agglomerated mud sand and fine stone powder in the tailing sand, local contour shaping is carried out on sand particles in the tailing sand through stone sizing, iron sizing and stone sizing, particle separation of mud powder and stone powder with particle size smaller than 0.075mm from the tailing sand is realized through tangential high-pressure air, and the separated mud powder and stone powder enter a dust remover along with high-pressure air flow to realize gas-solid separation.

Drawings

The structure of the device in figure 1 is simplified,

figure 2 is a front view of the rotating cage,

figure 3 is a top view of the rotating cage,

figure 4 is a front view of the impact plate,

figure 5 is a top view of the reaction plate,

figure 6 particle morphology visual comparison.

In the figure, 1 cylinder, 2 sand bins, 3 mud powder bins, 4 dust collectors, 5 impact plates, 6 impact plates, 7 feed inlets, 8 discharge outlets, 9 horizontal supports, 10 rotating cage spindles, 11 spreading plates, 12 rotating cages and 13 air inlet openings

Detailed Description

The present invention will be further described with reference to the following specific examples.

Example one

30 ten thousand tons of tailing sand with the thickness of 0-5 mm is produced in each year from sand stones of certain enterprises in Zhenjiang, and the tailing sand cannot effectively replace natural sand to be used for concrete materials due to the fact that mud powder content exceeds the standard. And (3) carrying out mud and powder removal experiments on the same tailings sand samples in 2017 in 4 months by using a V-shaped powder concentrator and the device of the method when the water content is different, wherein the results are shown in tables 1 and 2. When the water content of the tailing sand is lower, the V-shaped powder concentrator and the device of the methodThe silt and powder removing effect can treat the tailing sand into qualified machine-made sand, but the silt removing effect of the device is better. When the water content of the tailing sand is higher, the mud removing effect of the V-shaped powder concentrator is reduced rapidly, and the tailing sand can be processed into qualified machine-made sand by the device. By contrast, the enterprise selects the method and the mud and powder removing device. The installation and debugging are completed in 7 months in 2017, the sampling detection results in 8 months in 2017 are shown in table 3, the system achieves the efficient mud and powder removing effect of the tailing sand, and meanwhile, the particle shape of the product is optimized to a certain degree, as shown in the figure. At present, the device has the hour treatment capacity of 120 tons, the installed power of 37kw and the main shaft rotating speed of 250r/min, the sludge powder-containing waste gas at the outlet passes through a bag type dust collector, and the running air volume is 50000m³Hour and installed power of 75 kw. The comprehensive single ton treatment capacity consumes 0.96 kw.

TABLE 1, experiment condition of 2017 in 4 months

TABLE 1, 2017 experiment of 4 months in year 2 (II)

TABLE 2, 8 month's operating conditions of 2017

Claims (4)

1. a kind of tailings sand high-efficiency desliming and powder removal and particle shape optimization method, it is characterized in that, the raw material that adopts is mainly tailings sand, and wherein tailings sand water content is less than 4%, the mud powder and fine stone powder that also contain in tailings sand and The mud ball, wherein the total content of mud powder and fine stone powder is less than 15%, the particle size is less than 0.075mm, the content of the mud ball is less than 5%, and the particle size is greater than 0.075mm; it specifically includes the following steps: Step 1: Grain Shape Optimization 1) Pour the tailings sand into the spreading pan through the feeding port, the spreading disc rotating at high speed will centrifugally throw the tailings sand out at a linear speed of not less than 10m/s, and the tailings sand will be sputtered to the hood under the action of centrifugal force. On the counterattack plate on the periphery of the spreading plate, the mud balls, agglomerated mud sand and fine stone powder are dispersed by collision; 2) The sand particles rebounded by the impact plate hit the impact plate below the spreading plate at high speed again, and the rotation speed of the impact plate is not less than 150 rpm, which further realizes the dispersion of mud balls, agglomerated mud sand and fine stone powder; 3) The sand particles that are impacted by the rotating impact plate and fly to the impact plate collide with the sand particles rebounded by the impact plate, which further realizes the dispersion of mud balls, agglomerated mud sand and fine stone powder; 4) In the process of 1), 2), and 3) above, more than 90% of the mud balls larger than 0.075mm are broken into powder smaller than 0.075mm, and the sand particles and the fixed counterattack plate, the high-speed rotating paddle, and the high-speed flight The sand group of the sand grains is shaped by stone-on-iron, stone-on-stone and iron-on-stone to achieve local contour shaping, and the sand grains are more rounded; Step 2: Desilting and powder removal 1) The lower part of the cylinder is provided with an air inlet tangentially. In the process of step 1, the air flow is blown into the interior of the tumbler from the bottom and from the top, and flows to the tumbler impact plate and the impact plate fixed outside the tumbler under the action of the centrifugal force of the tumbler. The gap between them forms a high-pressure air flow. Based on the principle of gravity separation, the sand, mud and stone powder in the above 1), 2), and 3) processes are classified and separated, and the mud powder and fine stone powder less than 0.075mm are separated. The effect is not less than 85%; 2) The high-pressure air containing mud powder flows out of the cylinder tangentially through the air duct and enters the dust collector system to achieve gas-solid separation. warehouse. 2. The device used by a kind of tailings sand high-efficiency desliming and powder removal and particle shape optimization method according to claim 1, is characterized in that, comprises cylinder, sand silo, mud powder silo, cyclone dust collector, impact plate and The counterattack plate, the upper end of the cylinder is provided with a feeding port, the lower end of the cylinder is provided with a discharging port, and the lower part of the discharging port is connected with a sand bin; the upper part of the cylinder is provided with a rotating cage spindle along the central axis in the vertical direction, and the upper end of the spindle is provided with a rotating cage spindle. There is a spreader plate, and the lower part of the spreader plate is fixed with a plurality of impact plates in a ring shape around the main shaft; with the inner wall of the cylinder as a support point, there are also impact plates fixed from top to bottom between the inner wall of the cylinder and the rotating cage. The counterattack plate is formed into a ring; a tangential air inlet is arranged on the wall below the cylinder body and above the sand bin, and an air duct is connected to the air inlet outside the cylinder wall; A dust collector connected to the air outlet channel. 3. the device used for a kind of tailings sand high-efficiency desliming and powder removal and particle shape optimization method according to claim 2, is characterized in that, in order to improve the centrifugal acceleration effect of the rotating cage to the air intake, the impact plate and the rotating The included angle of the tangential direction of the cage's circumference is less than 90°; the impact plate is arranged from top to bottom, the diameter is from small to large, and the number of layers is not less than 2; the impact plate is a strip-shaped thickened plate , the upper and lower narrow sides of the impact plate are movably fixed on the rotating cage, so that the impact plate can be removed and turned 180° and fixed to the rotating cage when the working surface is worn down to the point where the desilting and powder removal efficiency cannot be satisfied, so that the reverse side of the impact plate can be fixed on the rotating cage. become a work surface. 4. The device used in a method for efficient desliming and powder removal and particle shape optimization of tailings sand according to claim 2, wherein the counterattack plate is a plate, and is arranged around the tumbler and supported by a cylinder, and a plurality of The combination of the impact plate is a ring-shaped polyhedron, and there are no less than two layers of impact plate layers with diameters ranging from small to large in the form of a ring polyhedron from top to bottom. Bottom-up air duct; the counterattack plate is fixed on the inner wall of the cylinder through the horizontal bracket, and the counterattack plate and the horizontal bracket are detachable and fixed. When the working surface of the counterattack plate is worn to the point where the desilting and powder removal efficiency cannot be satisfied, remove and turn 180 ° And again fixed to the cylinder wall through the support beam, the reverse side of the counterattack plate becomes the working surface.

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