CN116351549A - Method for improving yield of clean coal by recycling coarse peat - Google Patents

Abstract

The disclosure relates to the technical field of peat recovery, in particular to a method for improving the yield of clean coal by recycling coarse peat. Completely changing the underflow of the cyclone into a feeding box of the spiral separator; the separated clean coal and middlings of the spiral separator enter an arc screen for preliminary dehydration, and the separated gangue enters a gangue belt after being dehydrated by a high-frequency screen; the product dehydrated by the pulverized coal centrifuge is changed into a clean coal removing belt from a chute of the original pulverized coal removing belt. Through implementing the technical scheme of this disclosure, reduced the probability that gangue mud was built-up at centrifuge basket inner wall, a large amount of gangue of slime water system was selected out, reduced the probability that gangue mud was built-up at centrifuge basket inner wall to product moisture, ash content, sulphur are reduced, have improved the calorific capacity of product.

Description

Method for improving yield of clean coal by recycling coarse peat

Technical Field

The disclosure relates to the technical field of peat recovery, in particular to a method for recovering coarse peat.

Background

Part of coarse-grain gangue contained in a slime water system of a coal washery enters a dust coal belt after being dehydrated by a dust coal centrifuge, the coarse-grain gangue is tightly attached to the inner wall of a sieve basket under the action of the centrifuge in the sieve basket, and as part of gangue is easy to be slurried and catalyzed by centrifugal force, a thick layer of gangue mud can be gradually formed on the inner wall of the sieve basket after the centrifuge operates, so that the moisture of a product is seriously influenced, and ash and sulfur content of the product are also influenced by the gangue contained in the coarse-grain gangue.

In order to better maintain natural resources and fully utilize the natural resources, the yield of the clean coal is required to be further improved by the coarse peat recovery method. Aiming at improving the yield of clean coal, improving the economic benefit, reducing the treatment pressure of fine coal slime, reducing the wear rate of equipment and improving the utilization rate of equipment and resources, the method is the key point of the research in the coal washing field at present.

Disclosure of Invention

To solve or at least partially solve the above technical problems, the present disclosure provides a method for improving the yield of clean coal by recycling coarse peat, comprising the steps of,

step one: the magnetic separator is used as a desliming screen, materials smaller than 3mm in the desliming screen enter a coal slime barrel and then enter a water conservancy classification cyclone, and the materials larger than 3mm enter a shallow groove;

step two: the water conservancy classifying cyclone is screened, so that the materials with the diameter smaller than 0.25mm enter a concentration tank for sedimentation and are dehydrated by a pressure filter and a plate-and-frame filter press to enter a dust coal conveyor belt; the materials with the diameter of more than 0.25mm enter a spiral separator;

step three: the spiral separator is used for separating clean coal, middlings and gangue, wherein the clean coal and the middlings enter an arc-shaped screen, and the gangue enters a high-frequency screen;

step four: the arc screen is screened to enable the clean coal and the middlings smaller than 0.35mm to enter a concentration tank for sedimentation, and then the clean coal and the middlings are dehydrated by a pressure filter and a plate-and-frame filter press and enter the dust coal conveyor belt; the clean coal and the gangue with the diameter of more than 0.35mm and the diameter of less than 0.35mm in the high-frequency sieve enter a centrifugal machine together, the gangue with the diameter of less than 0.35mm in the centrifugal machine enter a concentration tank for sedimentation, and then enter a clean coal conveyor belt after being dehydrated by a pressure filter and a plate-and-frame filter press, and enter the clean coal conveyor belt with the diameter of more than 0.35 mm; and the waste rock entering conveyor belt with the diameter of more than 0.35mm in the high-frequency screen.

Optionally, a water spraying pipe is added to the desliming sieve, and part of the sieve plate is provided with a water weir.

Optionally, the curved screen is a vibrating curved screen.

Optionally, the magnetic separator removes a cover plate on the underflow pipe orifice and is connected with a hose under the pipe, and a clamp is arranged on the hose and is used for adjusting the flow of the underflow pipe orifice.

Optionally, the drum of the magnetic separator is provided with a water spraying device, and the water spraying direction is along the tangential direction of the cambered surface of the drum.

Optionally, the material entering the desliming screen is greater than 13mm.

Compared with the prior art, the beneficial effects of the present disclosure are: the method comprises the steps of completely changing the underflow of a cyclone into a feeding box of a spiral separator to separate clean coal, middling and gangue, enabling the clean coal and middling to enter an arc screen for preliminary dehydration, and enabling the separated gangue to enter a gangue belt after being dehydrated by a high-frequency screen; finally, the product dehydrated by the last coal centrifuge removes the clean coal belt, the method can effectively improve the yield of clean coal, and the probability of gangue mud accumulation in the inner wall of the centrifuge screen basket is reduced because a large amount of gangue is separated out, thereby reducing the moisture, ash content and sulfur content of the product and improving the calorific value of the product.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments of the present disclosure or the solutions in the prior art, the drawings that are required for the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a flow chart of steps of the present disclosure.

Wherein, 1-desliming screen; 2-a coal slime barrel; 3-shallow grooves; 4-water conservancy classification cyclone; 5-spiral separator; 6-arc-shaped screen; 7-a concentration tank; 8-a filter pressing device; 9-high frequency screen; 10-a pulverized coal conveyor belt; 11-a centrifuge; 12-a clean coal conveyor belt; 13-gangue conveyor belt; 101-clean coal; 102-middlings; 103-gangue.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, a further description of aspects of the present disclosure will be provided below. It should be noted that, without conflict, the embodiments of the present disclosure and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced otherwise than as described herein; it will be apparent that the embodiments in the specification are only some, but not all, embodiments of the disclosure.

Part of coarse-grain gangue contained in a slime water system of a coal washery enters a dust coal belt after being dehydrated by a dust coal centrifuge, the coarse-grain gangue is tightly attached to the inner wall of a sieve basket under the action of the centrifuge in the sieve basket, and as part of gangue is easy to be slurried and catalyzed by centrifugal force, a thick layer of gangue mud can be gradually formed on the inner wall of the sieve basket after the centrifuge operates, so that the moisture of a product is seriously influenced, and ash and sulfur content of the product are also influenced by the gangue contained in the coarse-grain gangue. And the yield of the clean coal is to be improved, so that natural resources are more fully used.

Based on the above, the embodiment of the disclosure provides a method for recycling coarse peat and improving the yield of clean coal, which is to completely change the underflow of a cyclone into a feeding box of a spiral separator to separate clean coal, middling and gangue, and further the clean coal and middling enter an arc screen for preliminary dehydration, and the separated gangue enters a gangue belt after being dehydrated by a high-frequency screen; finally, the product dehydrated by the last coal centrifuge removes the clean coal belt, the method can effectively improve the yield of clean coal, and the probability of gangue mud accumulation in the inner wall of the centrifuge screen basket is reduced because a large amount of gangue is separated out, thereby reducing the moisture, ash content and sulfur content of the product and improving the calorific value of the product.

The method for improving the yield of the clean coal by recycling the coarse peat is described in detail below by specific examples:

referring specifically to fig. 1, the present disclosure provides a method for improving the yield of clean coal by recycling coarse peat, comprising the steps of first flushing tailings of a magnetic separator in a coal preparation plant as a desliming screen 1 directly into a coal slime barrel 2. Preferably, the four desliming sieves 1 are added with one water spray, so that the desliming effect of the desliming sieves is improved, the coal slime content of the heavy medium suspension is reduced, the recovery efficiency of the magnetic separator is improved, and the mud content of lump coal is reduced. On the basis, a water spray pipe of the earlier stage desliming screen is also replaced by a stainless steel pipe, and part of the screen plates are also replaced by screen plates with water baffles, so that the desliming effect of the desliming screen is improved. Specifically, the desliming sieve 1 enters the water conservancy classification cyclone 4 after entering the coal slime barrel 2 with the sorting material smaller than 3mm, and the material directly enters the shallow groove 3 with the size larger than 3mm. The "3mm, 0.25mm, 0.35mm, etc." as described in this disclosure is the size fraction of coal.

It should be noted that in the actual production process, the tailings of the magnetic separator must ensure a certain overflow amount (about 25% of the tailings) to obtain a better separation effect, the overflow amount of the tailings of the magnetic separator is realized by adjusting the bottom flow of the tailings, the adjustment of the bottom flow of the existing tailings is realized by changing the size of the pipe orifice by moving the cover plate on the bottom flow pipe of the tailings, during production, the cover plate and the bottom flow pipe orifice are immersed in the ore pulp, the operation cannot be seen, and meanwhile, the pressure generated by the ore pulp is also present, so that the adjustment is very inconvenient, the effect is poor, and the stability of the overflow amount cannot be ensured. In view of this, the present disclosure removes the cover plate on the underflow nozzle and connects a section of rubber hose under the pipe, installs a clip on the rubber hose, and changes the size of the flow by adjusting the tightness of the clip. After transformation, the new device can conveniently and accurately regulate the bottom flow of the tailings, ensure that the tailings always have stable and proper overflow quantity, and ensure the sorting effect.

Further, in some embodiments of the present disclosure, the magnetic separator concentrate discharge apparatus is also optimized. Specifically, the suspension of pan feeding is under the effect of magnetic field, and the medium is adsorbed on the surface of cylinder and is taken to concentrate discharge end along with the rotation of cylinder, falls into concentrate inslot under the effect of leather scraper. Because the roller of the magnetic separator is worn to different degrees, the leather scraper can not scrape all the adsorbed media, so that part of the media are carried into the separation tank again, and are lost in tailings under the impact of ore pulp, so that the tailings are carried, and the consumption of the media is increased.

Through various references, a row of water spray is arranged along the full width of the roller, and the water spray direction is along the tangential direction of the cambered surface of the roller as much as possible so as to strengthen the medium removing effect, so that concentrate which is not scraped by the scraper is discharged into the concentrate groove under the action of water spray, the concentrate loss is avoided, and the medium consumption is reduced.

Further, the water conservancy classifying cyclone 4 screens materials smaller than 0.25mm, the materials enter the concentration tank 7 for sedimentation and are dehydrated by the filter pressing device 8 and enter the pulverized coal conveyor belt 10, and the specific filter pressing device 8 can be a pressure filter or a plate-and-frame filter press; the material greater than 0.25mm enters the spiral separator 5. The hydraulic classification cyclone 4 is a high-efficiency classification desliming device, is influenced by various aspects in the production process, can reduce the separation efficiency of the hydraulic classification cyclone, mainly is the influence of the feeding pressure and the size of an underflow nozzle, and needs to adjust the frequency of a feeding pump and the size of a feeding valve in time during daily maintenance so as to ensure the feeding pressure of the hydraulic classification cyclone. After the underflow nozzle is used for a long time, the blanking opening can be enlarged, the pressure is greatly influenced, and the underflow nozzle needs to be replaced in time.

Step three: the spiral separator 5 separates clean coal 101, middlings 102 and gangue 103, wherein the clean coal 101 and middlings 102 enter an arc screen 6, and the gangue 103 enters a high-frequency screen 9; specifically, because the cyclone underflow contains large particles and the concentration of the underflow is large, the feeding of the spiral separator is not smooth, and a feeding pipe is often blocked, so that the labor intensity is increased for posts. Through field measurement and research, the spiral separator feed inlet grate and the dilution water pipe are processed. The grate at the feed inlet of the spiral separator and the dilution water pipe are modified. The underflow of the cyclone is well diluted and screened, so that the problems of unsmooth feeding and blockage of the spiral separator are well solved, and the separation efficiency of the spiral separator is improved.

Step four: the arc screen 6 is screened to ensure that the clean coal 101 and the middlings 102 smaller than 0.35mm enter the concentration tank 7 for sedimentation, and then are dehydrated by the filter pressing device 8 and enter the dust coal conveyor belt 10; the clean coal 101 and the gangue 103 with the diameter of more than 0.35mm and the diameter of less than 0.35mm in the high-frequency screen 9 enter a centrifugal machine 11 together, materials with the diameter of less than 0.35mm in the centrifugal machine 11 enter a concentration tank 7 for sedimentation, are dehydrated by a filter pressing device and enter a clean coal conveyor belt 10, and enter a clean coal conveyor belt 12 with the diameter of more than 0.35 mm; the material larger than 0.35mm in the high-frequency screen 9 enters the gangue conveyor 13. Because the raw coal slime is serious in mud formation, when the water content of raw coal is more than 13.5%, and a large amount of superfine slime is generated in the production process, so that an arc-shaped dewatering screen plate and a centrifugal screen basket are often blocked, the arc-shaped dewatering screen plate and the centrifugal screen basket of the end coal are poor in dewatering effect, and the highest water content of coarse slime is 25%. Thus, in a preferred embodiment, the present disclosure modifies the curved screen 6 to be a vibrating curved screen so that the system equipment operates steadily, the coarse slime dewatering effect is improved, and centrifuge moisture is reduced.

Theoretical calculations by practicing the present disclosure are as follows:

in each table, Q is expressed as power, r is expressed as desliming screen product rate, and a is expressed as ash.

1. Pre-desliming

In order to meet the process requirements and to ensure the purity of the suspension, the coal must be desliming before entry, with a desliming efficiency of 85%, which can be calculated initially:

TABLE 1 desliming screening

As can be seen from the above table, the yield of the desliming screen undersize product was 8.18% and the ash content was 25.94%.

2. Magnetic dressing tailings

The tailings of the magnetic separator in the coal separation plant directly enter a coal slime barrel as a desliming screen for flushing. Calculated as 100% magnetic separation efficiency.

Table 2, separator separation

As can be seen from the above table, the yield of the tailings slime of the magnetic separator is 1.15% and the ash content is 33.23%.

3. Classifying by hydraulic classifying cyclone

The materials can be obtained into two different particle sizes of +025mm and-0.25 mm through a water conservancy classification cyclone, wherein +0.25mm is coarse slime, and-0.25 mm is fine slime.

TABLE 3 classifying by hydraulic classifying cyclone

As can be obtained from the above table, the cyclone underflow yield was 3.44% and the ash 15.06%.

4. Sorting by a spiral sorting machine

The underflow of the cyclone is separated by a spiral separator to obtain three products, and the middling and the clean coal are simultaneously dehydrated by an arc screen and are combined at one place.

Table 4, spiral classifier classification

From the above table, clean coal yield was 2.65%, ash content was 5.75%, gangue yield was 0.79%, and ash content was 53.15%.

TABLE 5, curved screen and centrifuge dewatering sorting

As can be seen from the above table, the centrifugate yield was 0.15% and the ash content was 7.75% while the high frequency screen undersize yield was also 0.15%. The yield of the dehydrated material was 2.5% and the ash content was 5.62.

6. The method can obtain by integrating the coarse slime recovery equipment

From Table 6, it can be seen that the clean coal yield after modification can be increased by 2.5% and the dust coal yield can be reduced by 3.44% (without deducting the centrifugate and the high frequency screen undersize).

TABLE 6 coarse slime recovery

It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a specific embodiment of the disclosure to enable one skilled in the art to understand or practice the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown and described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. The method for improving the yield of the clean coal by recycling the coarse peat is characterized by comprising the following steps of,

step one: the magnetic separator is used as a desliming screen (1), materials smaller than 3mm in the desliming screen (1) enter a coal slime barrel (2) and then enter a water conservancy classification cyclone (4), and the materials larger than 3mm enter a shallow groove (3);

step two: the water conservancy classifying cyclone (4) screens to ensure that the materials smaller than 0.25mm enter a concentration tank (7) for sedimentation, and then enter a dust coal conveyor belt (10) through dehydration of a filter pressing device (8); the materials with the diameter of more than 0.25mm enter a spiral separator (5);

step three: the spiral separator (5) is used for separating clean coal (101), middlings (102) and gangue (103), wherein the clean coal (101) and the middlings (102) enter an arc-shaped screen (6), and the gangue (103) enters a high-frequency screen (9);

step four: the arc screen (6) is screened to enable the clean coal (101) and the middlings (102) to be smaller than 0.35mm, enter the concentration tank (7) for sedimentation, and then are dehydrated by the filter pressing device (8) and enter the dust coal conveyor belt (10); the clean coal (101) and the gangue (103) with the diameter of more than 0.35mm in the middlings (102) and the gangue (103) with the diameter of less than 0.35mm in the high-frequency screen (9) enter a centrifugal machine (11), the materials with the diameter of less than 0.35mm in the centrifugal machine (11) enter the concentration tank (7) to be settled, and then are dehydrated by a filter pressing device and enter the clean coal conveyor belt (10), and the materials with the diameter of more than 0.35mm enter the clean coal conveyor belt (12); the material greater than 0.35mm in the high-frequency screen (9) enters the gangue conveyor belt (13).

2. The method for improving the yield of clean coal by recycling coarse peat according to claim 1, wherein a water spraying pipe is added to the desliming sieve, and part of the sieve plate is provided as a sieve plate with a water weir.

3. The method for improving the yield of clean coal by recycling coarse peat according to claim 1, wherein the curved screen (6) is a vibrating curved screen.

4. The method for improving the yield of clean coal by recycling coarse peat according to claim 1, wherein the magnetic separator removes a cover plate on an underflow pipe orifice and is connected with a hose under the pipe, and a clamp is installed on the hose and used for adjusting the flow rate of the underflow pipe orifice.

5. The method for improving the yield of clean coal by recycling coarse peat according to claim 1, wherein the drum of the magnetic separator is provided with a water spraying device, and the water spraying direction of the water spraying device is along the tangential direction of the cambered surface of the drum.

6. A method for improving the yield of clean coal by coarse peat recovery according to claim 1, characterized in that the material entering the desliming screen (1) is larger than 13mm.

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