CN116474892A - Grinding system and method for improving activity index of sludge ash - Google Patents

Abstract

The invention provides a grinding system for improving the activity index of sludge ash, which comprises a feeding device, wherein a vertical mill is arranged at the discharge end of the feeding device, a gas box pulse dust collector is arranged at the discharge end of the vertical mill, the air outlet end of the gas box pulse dust collector is connected with a centrifugal fan, and a finished product bin is arranged at the output end of the gas box pulse dust collector.

Description

A grinding system and method for increasing the activity index of sludge ash

technical field

The invention relates to the technical field of resource utilization of solid waste, in particular to a grinding system and method for increasing the activity index of sludge ash.

Background technique

As a "derivative" of sewage treatment, sludge production continues to increase with the increase in sewage treatment volume. At present, the sludge incineration treatment process can achieve harmlessness, reduction, energy recovery, etc. to the greatest extent, and has become one of the mainstream technologies for sludge treatment and disposal in my country. After the sludge is incinerated, the organic matter in the sludge is effectively destroyed. The main components of the sludge incineration ash are SiO ₂ , Al ₂ O ₃ , CaO, Fe ₂ O ₃ and P ₂ O ₅ . According to statistics, 40-50% of the sludge ash will be produced in the sludge incineration treatment. The increasing sludge ash has brought increasingly serious impact on the environment. Therefore, it is of great significance to find a more effective, more environmentally friendly and more economical treatment process.

In order to solve the above problems, Chinese patent 202110878084.9 discloses a method for producing geopolymers from sludge incineration ash, including water glass solution configuration; raw material mixing and sieving treatment; slurry mixing and injection molding; Although this method can obtain high-quality cementitious materials, which can replace Portland cement, this method is obtained through chemical methods, and the cost is relatively high. It not only consumes a lot of water resources, but also easily causes water pollution. Chinese patent 202210178476.9 discloses a cement mixture material for municipal sludge and domestic waste incineration ash and its preparation system, method and application. By optimizing the ratio of urban sludge incineration ash and municipal waste incineration fly ash, crushing and grinding, sorting and removing impurities, the mixed material obtained has a high strength index and can effectively replace Portland cement. Although this method reduces the consumption of water resources in the process of solid waste disposal, and the utilization of resources has good sustainable development characteristics, but this preparation system uses devices such as double-roll crushers, ball mills, primary cyclone dust collectors, secondary cyclone dust collectors, and bag type dust collectors.

Contents of the invention

The invention provides a grinding system and method for increasing the activity index of sludge ash. Through the mechanism of mechanical activation, the obtained sludge ash powder has higher activity, and as a high-value gelling material, it provides technical support for the resource utilization of sludge ash in cement, and the production process is efficient and energy-saving.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

A grinding system for improving the activity index of sludge ash, comprising:

feeding device;

A vertical mill, the vertical mill is arranged at the discharge end of the feeding device;

An air box pulse dust collector, the air box pulse dust collector is arranged at the discharge end of the vertical mill, and the outlet end of the air box pulse dust collector is connected with a centrifugal fan; and

The finished product warehouse, the finished product warehouse is set at the output end of the air box pulse dust collector;

Wherein, the material entering the vertical mill forms a stable material layer in the vertical mill, and forms ash powder through mechanical activation.

Preferably, the feeding device includes:

Raw materials warehouse;

Sealed metering scale, the feed end of the sealed metering scale is connected to the discharge end of the raw material bin;

A screw feeder, the feed end of the screw feeder is connected to the discharge end of the sealed metering scale; and

Bucket elevator, the feed end of the bucket elevator is connected with the discharge end of the screw feeder, and the discharge end of the bucket elevator is connected with the feed end of the vertical mill.

Preferably, the air outlet end of the centrifugal fan is also connected to the air inlet end of the vertical mill through a return air duct.

Preferably, the powder device further includes a pneumatic conveyor, the feed end of the pneumatic conveyor is connected to the discharge end of the air box pulse dust collector, and the discharge end of the pneumatic conveyor is connected to the feed end of the finished product bin.

Preferably, the vertical mill includes a cabinet, the cabinet includes a feeding bin and a grinding bin, the feeding buffer is provided in the feeding bin, and the grinding bin includes a grinding disc arranged on the cabinet, a grinding roller extending from the grinding disc to the grinding bin, and a material distribution device extending from the grinding disc to the grinding bin and the feeding bin, respectively.

Preferably, the feed buffer device includes a connecting flange, a skirt plate and a material guide plate, the skirt plate forms a cavity structure through four wear-resistant plates, the material guide plate is distributed on both sides of the feed channel and forms a V shape, and the included angle between the material guide plate and the skirt plate is 40-45°.

Preferably, the distributing device includes a support rod, a connecting rod and a paving board, the supporting rod is connected to the grinding chamber, the paving board is connected to the supporting rod through a connecting rod, the vertical height difference between the paving board and the grinding disc is 50-100 mm, and the height can be adjusted through the connecting rod.

Preferably, the vertical mill further includes a sorting device, and the sorting device includes a powder sorting device connected with the material distribution device, a dust collector connected with the powder sorting device, and a coarse powder return hopper connected with the powder sorting device at one end and connected with the feeding buffer device at the other end.

A powder method for sludge ash, comprising the aforementioned powder system, comprising the steps of:

S1: The raw material of sludge and ash is transported to the vertical mill through the feeding device;

S2: The sludge ash moves to the grinding track under the centrifugal force of the vertical mill to form a stable material layer, and the sludge ash powder is obtained under the action of mechanical activation;

S3: The sludge ash powder that meets the particle size requirements is collected by the air box pulse dust collector and transported to the finished product warehouse.

Preferably, the powder method also includes:

S21: After the sludge ash enters the vertical mill, it is evenly scattered on the grinding table through the feeding buffer device, and moves to the grinding track under the centrifugal force generated by the rotation of the grinding table;

S22: A stable material layer is formed under the action of the distributing device, and the sludge ash powder is obtained by extrusion, shearing and friction of the grinding roller and the grinding disc;

S23: The ground powder is transported to the powder selection device for control and treatment, and the powder that meets the particle size requirements is collected by the air box pulse dust collector and transported to the finished product warehouse by the pneumatic conveyor;

S24: The powder that does not meet the particle size requirements is returned to the grinding table through the coarse powder return hopper to continue grinding.

Preferably, the pressure of the grinding roller is 850-1000 KN/m ² ; the rotational speed of the grinding disc is 23-25 r/min.

As can be seen from the above technical solutions, the present invention has the following beneficial effects:

1. In the present invention, the sludge and ash raw material is measured by a sealed metering scale and then transported to the vertical mill by a screw feeder and a bucket elevator. Under the action of the centrifugal force generated by the rotating grinding disc, it moves to the grinding track and forms a stable material layer under the action of the material distribution device. Deep grinding and physical activation are carried out by the extrusion, shearing and frictional multi-dimensional force fields of the grinding roller and grinding disc. Micro-powder, an effective substitute for Portland cement.

2. In the present invention, during the grinding process, the centrifugal fan lifts the ground fine powder to the powder selection device for control and treatment by air force. The fine powder with a particle size of ≤ 150 μm is collected by the air box pulse dust collector and transported to the finished product warehouse through a pneumatic conveyor. Since the grinding roller and the grinding disc of the vertical mill are not in direct contact during work, the service life is long, the wear is less and there is no metal impact sound of the ball mill, the vibration is small, the noise is low, and the energy consumption is low. The system adopts a fully sealed design and operates in a negative pressure environment, without dust, and the environment is clean. Through the above process, in the process of resource utilization of sludge and ash, the consumption of water resources and carbon emissions can be effectively reduced, which has significant social and economic benefits.

Description of drawings

Fig. 1 is the structural representation of the grinding system provided by the present invention;

Fig. 2 is the structural representation of vertical mill;

Fig. 3 is the flowchart of grinding method provided by the present invention;

Fig. 4 is the structural representation of feed buffer device;

Fig. 5 is a schematic diagram of the connection between the distributing device and the grinding disc.

In the figure: 110, raw material bin; 120, sealed metering scale; 130, screw feeder; 140, bucket elevator; 20, vertical mill; 210, chassis; 211, feeding bin; 212, grinding bin; 220, powder selection device; , Feed buffer device; 261, connecting flange; 262, skirt plate; 263, material guide plate; 270, coarse powder return hopper; 30, air box pulse dust collector; 40, centrifugal fan;

Implementation

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Example

Referring to Fig. 1 , a grinding system for improving the activity index of sludge ash comprises a feeding device, a vertical mill 20, an air box pulse dust collector 30 and a finished product bin 50, the vertical mill is arranged at the discharge end of the feeding device, the air box pulse dust collector is arranged at the discharge end of the vertical mill, and the outlet end of the air box pulse dust collector is connected to a centrifugal fan 40, and the outlet end of the centrifugal fan 40 is also connected to the air inlet end of the vertical mill 20 through a return air pipeline. The finished product bin 50 is set at the output end of the air box pulse dust collector 30. When in use, the sludge ash raw material enters the vertical mill 20 through the feeding device, forms a stable material layer in the vertical mill, and undergoes deep grinding under the action of multi-dimensional force fields of extrusion, shearing and friction in the vertical mill 20 to form ash powder by mechanical activation. The uniformity coefficient of the particles, through the mechanism of mechanical activation, can obtain higher activated sludge ash powder, which can effectively replace Portland cement.

Furthermore, the outlet end of the centrifugal fan 40 is connected to the air inlet end of the vertical mill 20 through the air return duct, which can effectively use the air volume of the fan, reduce dust emission, and make the production process of the production system more environmentally friendly.

As a preferred technical solution of the present invention, the feeding device includes a raw material bin 110, a sealed metering scale 120, a screw feeder 130, and a bucket elevator 140. The feed end is connected to the feed end of the vertical mill 20. During use, the sludge and ash in the raw material bin 110 is measured by the sealed metering scale 120 and then sent to the screw feeder 130, and then sent to the bucket elevator 140 through the screw feeder 130, and then sent to the vertical mill 20 through the bucket elevator 140.

Further, the raw material bin 110 is equipped with a weighing sensor, and the weight of the sludge and ash discharged from the raw material bin 110 can be continuously and real-time monitored through the measurement of the sealed measuring scale 120, so as to avoid production failure caused by abnormal feeding. The screw feeder 130 can spirally agitate and discharge the sludge and ash, which can make the sludge and ash particles more uniform, and is more beneficial to subsequent mechanical activation.

Further, the powder device also includes a pneumatic conveyor 60, the feed end of the pneumatic conveyor is connected to the discharge end of the air box pulse dust collector 30, and the discharge end of the pneumatic conveyor is connected to the feed end of the finished product bin 50. In this way, the ash collected by the air box pulse dust collector 30 is transported to the finished product bin 50 by the pneumatic conveyor 60 for storage.

As a preferred technical solution of the present invention, referring to FIG. 2 , the vertical mill 20 includes a cabinet 210, the cabinet includes a feeding bin 211 and a grinding bin 212, further, a feeding buffer device 220 is provided in the feeding bin, and the grinding bin includes a grinding disc 230, a grinding roller 240 and a material distribution device 250. The grinding disc 230 is arranged inside the cabinet 210, and is specifically located at the bottom of the grinding bin 212. The grinding chamber 212 extends, and the grinding rollers 240 are arranged symmetrically. Specifically, in the present invention, the number of the grinding rollers 240 is two, and extend from the grinding disk 230 to the grinding chamber 212. The track is in a loose state when grinding, pre-compacted, shaped and exhausted by the material distribution device 250, forming a flat and compact material layer, and then enters the grinding roller 240 for extrusion, shearing and rubbing, so that the grinding roller 240 will not be compressed and cause vibration, which is beneficial to improving the grinding efficiency and production stability of the mill.

Further referring to FIG. 4 , the feed buffer device 260 includes a connecting flange 261, a skirt plate 262 and a material guide plate 263. The skirt plate forms a cavity structure through four wear-resistant plates. The material guide plate 263 is distributed on both sides of the feed channel and forms a V shape. 0 impact, improve the stability of the mill operation, and prolong the service life of the grinding disc.

Further referring to FIG. 5 , the distributing device 250 includes a support rod 251 , a connecting rod 252 and a paving board 253 . The supporting rod 251 is connected to the grinding chamber 212 . The paving board 253 is connected to the supporting rod 251 through the connecting rod 252 . When the material is centrifugally moved on the grinding disc 230, there will be ups and downs. When passing through the paving board 253, it will be pre-pressed by the paving board and paved to form a material layer with uniform thickness, which improves the stability of the mill operation and improves the grinding efficiency of the grinding roller 240 at the same time.

Further, the vertical mill 20 also includes a sorting device, the sorting device includes a powder selection device 260, a dust collector and a coarse powder return hopper 270, the powder selection device 260 is connected to the material distribution device 250, the dust collector is connected to the powder selection device, one end of the coarse powder return hopper 270 is connected to the powder selection device, and the other end is connected to the feeding buffer device 220. Under the action of the centrifugal force generated by the rotating grinding disc 230, it moves to the grinding track, forms a stable material layer under the action of the distributing device 250, undergoes deep grinding and physical activation under the action of the multi-dimensional force field of extrusion, shearing and friction of the grinding roller 240, reduces the average particle size of the sludge ash particles and increases the uniformity coefficient of the particles, and obtains a relatively high activated sludge ash powder through the mechanism of mechanical activation. During the grinding process, the centrifugal fan 40 lifts the ground fine powder to the powder selection device 260 for control and treatment by air force. The fine powder with a particle size of ≤150 μm is collected by the air box pulse dust collector 30 and transported to the finished product bin 50 through the pneumatic conveyor 60. The particles with a particle size of >150 μm are returned to the grinding table 230 through the coarse powder return hopper 270 to continue grinding. Among them, the pressure of the grinding roller 240 of the vertical mill 20 is controlled at 850KN/m ² ~ 1000KN/m ² , the rotation speed of the grinding disc 230 is controlled at 23r/min ~ 25r/min, and the wind pressure of the centrifugal fan 40 is preferably 5KPa ~ 6KPa, so that it can just suck the fine powder with a particle size of ≤ 150μm into the pulse dust collector 30 of the air box for collection. It should be noted that the vertical mill 20 does not directly contact the grinding roller 240 and the grinding disc 230 during operation, has a long service life, less wear and no metal impact sound of the ball mill, small vibration, low noise (20-25 decibels lower than the ball mill), and low energy consumption (30% to 40% energy saving than the ball mill).

Referring to Fig. 3, the present invention also provides a powder method for sludge ash, including the aforementioned powder system, specifically comprising the following steps:

S1: The raw material of sludge and ash is transported to the vertical mill through the feeding device.

Specifically, the sludge ash is transported through the feeding device, and enters the vertical mill through the output end of the feeding device.

S2: The sludge ash moves to the grinding track under the centrifugal force of the vertical mill to form a stable material layer, and the sludge ash powder is obtained under the action of mechanical activation.

Specifically, under the action of the centrifugal force of the vertical mill, the sludge and ash entering the vertical mill will move to the grinding track and form a stable material layer, and then undergo deep grinding and physical activation treatment under the action of multi-dimensional force fields of extrusion, shearing, and friction on the inner diameter of the vertical mill to form ash powder.

S3: The sludge ash powder that meets the particle size requirements is collected by the air box pulse dust collector and transported to the finished product warehouse.

Specifically, when the particle size of the powder obtained in the above S2 meets certain requirements, specifically in the present invention, the fine powder with a particle size of ≤150 μm is collected by the air box pulse dust collector and finally transported to the finished product bin. Of course, the fine powder that does not meet the particle size requirements, such as the fine powder with a particle size of >150 μm, is returned to the vertical mill for continuous grinding.

As a preferred technical solution of the present invention, the powder method also includes:

S21: After the sludge and ash enter the vertical mill, they are evenly scattered on the grinding disc through the feeding buffer device, and move to the grinding track under the centrifugal force generated by the rotation of the grinding disc.

Specifically, the sludge and ash conveyed by the feeding device first enters the feeding buffer device. The feeding buffer device is a circular cavity set above the center of the grinding disc. When the material enters the mill, the material enters the cavity, which can effectively prevent the material from rushing directly to the grinding disc, causing the material to quickly accumulate on the edge of the grinding disc, resulting in fluctuations in the thickness of the material layer, which affects the grinding efficiency and operation stability of the mill. move.

S22: A stable material layer is formed under the action of the distributing device, and is squeezed, sheared and rubbed by the grinding roller and the grinding disc to obtain sludge ash powder.

Specifically, when the material moves to the grinding track under the action of the centrifugal force generated by the rotating grinding disc, since the material is in a loose state when it moves to the grinding track, it should be noted that the material distribution device is an arc-shaped plate arranged between two grinding rollers. The material distribution device is pre-compacted, shaped and exhausted to form a flat and compact material layer before entering the grinding roller for extrusion, shearing and rubbing, so that the grinding roller will not be compressed and produce vibration, so as to improve the grinding efficiency and production stability of the mill.

S23: The ground powder is transported to the powder selection device for control and treatment, and the powder meeting the particle size requirements is collected by the air box pulse dust collector and transported to the finished product warehouse by the pneumatic conveyor.

Specifically, the powder selection device controls the fine powder to meet the particle size requirements, that is, the sludge ash powder with a particle size of ≤150 μm is collected by the dust collector and finally transported to the finished product warehouse, and the particle size distribution of the prepared sludge ash powder is calculated by the mass percentage of the sieve. The content of 0μm is 10%~15%, and the content of >80μm is 5~10%. At the same time, the fineness of sludge ash powder is controlled at 0.045mm, and the sieve residue is ≤20%, and the specific surface area is controlled ≥400m²/kg, and the 28-day activity index of the sludge ash micropowder is controlled to be ≥70%.

S24: The powder that does not meet the particle size requirements is returned to the grinding table through the coarse powder return hopper to continue grinding.

Specifically, the sludge ash powder that does not meet the particle size requirements (that is, particle size > 150 μm) is fed into the coarse powder return hopper into the feeding buffer device for continuous grinding.

According to GB/T 19077.1-2008 Particle Size Analysis-Laser Diffraction Method-Part 1-General Rules, the particle size distribution of the micropowder prepared by the grinding system of the present invention was tested in each interval, and the results are shown in Table 1.

The particle size distribution table of each interval of the micropowder prepared by table 1-grinding system of the present invention:

In addition, according to the GB/T 17671-2021 cement mortar strength test method (ISO method), the sludge ash raw material and the above-mentioned micropowder and ordinary Portland cement were tested for strength. The properties are shown in Table 2, Table 3 and Table 4 respectively.

Table 2 - Sludge ash raw material strength test table:

Table 3-micropowder strength test table prepared by the present invention:

The cement strength test table that the micropowder prepared by the present invention makes:

The fineness of the fine powder produced by the grinding system and process provided by the invention is controlled to be 0.045 mm or less than 20%, the specific surface area is controlled to be greater than or equal to 400m ² /kg, and the 28-day activity index of the sludge ash fine powder is controlled to be greater than or equal to 70%. The properties are shown in Table 5.

Table 5-performance comparison table of micropowder prepared by the present invention and raw materials:

It can be seen from Table 1, Table 2, Table 3 and Table 4 that the micropowder prepared by the present invention has an activity index increased by more than 60%, and can effectively replace Portland cement.

The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection determined by the claims of the present invention.

Claims (11)

1. A grinding system for increasing the activity index of sludge ash, comprising:

a feeding device;

the vertical mill (20) is arranged at the discharge end of the feeding device;

the air box pulse dust collector (30) is arranged at the discharge end of the vertical mill, and the air outlet end of the air box pulse dust collector is connected with a centrifugal fan (40); and

the finished product bin (50) is arranged at the output end of the air box pulse dust collector (30);

wherein the material entering the vertical mill (20) forms a stable layer in the vertical mill and forms ash powder by mechanical activation.

2. The grinding system for increasing the activity index of sludge ash as claimed in claim 1, wherein said feeding means comprises:

a raw material bin (110);

the feeding end of the sealed metering scale (120) is connected with the discharging end of the raw material bin (110);

the feeding end of the screw feeder (130) is connected with the discharging end of the sealed metering scale; and

and the feeding end of the bucket elevator is connected with the discharging end of the screw feeder (130), and the discharging end of the bucket elevator is connected with the feeding end of the vertical mill (20).

3. The grinding system for improving the activity index of sludge ash residues according to claim 2, wherein the air outlet end of the centrifugal fan (40) is further connected with the air inlet end of the vertical mill (20) through an air return pipeline.

4. A grinding system for increasing the activity index of sludge ash as claimed in claim 3, characterized in that the powder device further comprises a pneumatic conveyor (60), the feed end of which is connected to the discharge end of the air box pulse dust collector (30), and the discharge end of which is connected to the feed end of the finished product bin (50).

5. The grinding system for improving the activity index of sludge ash according to claim 4, characterized in that the vertical mill (20) comprises a machine box (210), the machine box comprises a feeding bin (211) and a grinding bin (212), a feeding buffer device (260) is arranged in the feeding bin, the grinding bin comprises a grinding disc (230) arranged on the machine box (210), a grinding roller (240) extending from the grinding disc to the grinding bin (212) and a distributing device (250) extending from the grinding disc to the grinding bin and the feeding bin respectively.

6. The grinding system for improving the activity index of sludge ash according to claim 5, characterized in that the feeding buffer device (260) comprises a connecting flange (261), a skirt plate (262) and a material guiding plate (263), the skirt plate (262) forms a cavity structure through four wear plates, the material guiding plate (263) is distributed on two sides of a feeding channel and forms a V shape, and an included angle between the material guiding plate (263) and the skirt plate (262) is 40-45 degrees.

7. The grinding system for improving the activity index of sludge ash according to claim 5, characterized in that the distributing device (250) comprises a supporting rod (251), a connecting rod (252) and a spreading plate (253), the supporting rod (251) is connected with the grinding bin (212), the spreading plate (253) is connected with the supporting rod (251) through the connecting rod, and the vertical height difference between the spreading plate and the grinding disc is 50-100 mm and can be adjusted through the connecting rod.

8. The grinding system for increasing the activity index of sludge ash as claimed in claim 6, wherein said vertical mill (20) further comprises a sorting device comprising a powder selecting device (220) connected to a distributing device (250), a dust collector connected to the powder selecting device, and a coarse powder returning hopper (270) connected to the powder selecting device at one end and to a feeding buffer device (260) at the other end.

9. A powder process for sludge clinker, characterized by comprising a powder system according to any of claims 1-7, comprising the steps of:

s1: the sludge ash raw material is conveyed to a vertical mill through a feeding device;

s2: the sludge ash moves to a grinding track under the centrifugal force of the vertical mill so as to form a stable material layer, and sludge ash powder is obtained under the mechanical activation;

s3: the sludge ash powder meeting the particle size requirement is collected by an air box pulse dust collector and is conveyed to a finished product bin.

10. The powder method of claim 8, further comprising:

s21: after entering the vertical mill, the sludge ash is uniformly scattered on the millstone through the feeding buffer device and moves towards the grinding track under the centrifugal force generated by the rotation of the millstone;

s22: forming a stable material layer under the action of a material distribution device, and extruding, shearing and rubbing the stable material layer by a grinding roller and a grinding disc to obtain sludge ash powder;

s23: the ground powder is conveyed to a powder selecting device for regulation and control treatment, and the powder meeting the particle size requirement is collected by an air box pulse dust collector and conveyed to a finished product bin by a pneumatic conveyor;

s24: the powder which does not meet the particle size requirement returns to the millstone through the coarse powder return hopper to continue grinding.

11. The powder process according to claim 9, wherein the grinding roller has a pressure of 850-1000 KN/m ² The method comprises the steps of carrying out a first treatment on the surface of the The rotating speed of the grinding disc is 23-25 r/min.