A process and system for the sorting of multi-product chemical coal

Abstract

This invention relates to the field of silicon coal production technology, specifically to a separation process and system for multi-product chemical coal. The process includes the following steps: raw materials are fed into a primary heavy medium three-product hydrocyclone for primary separation to obtain primary clean coal; the primary clean coal is fed into a secondary heavy medium three-product hydrocyclone for further separation to obtain ultra-low ash clean coal; the ultra-low ash clean coal undergoes pre-desmudging via an arc screen, desmudging via a desmudging screen, dewatering, and grading to obtain silicon coal products; wherein, the pre-desmudging of ultra-low ash clean coal is carried out in the secondary clean coal arc screen, the desmudging via a desmudging screen is carried out in the secondary clean coal double-layer desmudging screen, and dewatering is carried out in a silicon coal centrifugal dewatering machine; during the primary separation, the separation density is 1.4-1.6 g / cm³. 3 During re-sorting, the sorting density is 1.25-1.3 g / cm³. 3 The system includes a primary heavy medium three-product hydrocyclone and a secondary heavy medium three-product hydrocyclone. This invention achieves high-precision production of silicon coal, with a target clean coal ash content of ≤3%, fully utilizing the efficient separation capacity of the heavy medium three-product hydrocyclone, reducing clean coal loss, and improving economic efficiency.

Description

Technical Field

[0001] This invention relates to the field of silicon coal production technology, and in particular to a sorting process and system for coal used in multi-product chemical processing. Background Technology

[0002] Industrial silicon, with its reducing and alloy-modifying properties, is a key raw material in industrial production, primarily used in alloy production, chemicals, photovoltaics and electronics, refractory materials, and other specialized fields. Silicon coal, used as a carbonaceous reducing agent in the smelting of silica in an electric arc furnace to produce industrial silicon, has strict requirements regarding ash content, iron content, and particle size. Coking coal, a high-quality coal refined through washing and impurity removal, has a wide range of uses, serving as coking coal, chemical coal, and other general-purpose industrial coal. Although both silicon coal and coking coal are refined coals, there are significant differences in their ash and iron content.

[0003] Currently, the main processes for producing silicon coal are jigging and dry separation. However, when using jigging and dry separation processes to produce silicon coal, these two coal preparation methods have lower separation accuracy than the heavy medium three-product hydrocyclone process. When difficult-to-select coal types are selected, the ash content of the silicon coal product exceeds the standard, making it difficult to guarantee the quality. At the same time, it will reduce the recovery rate of silicon coal and coking coal products, lose clean coal, and reduce economic benefits. Therefore, those skilled in the art have always hoped to realize the heavy medium three-product hydrocyclone process for producing silicon coal.

[0004] The problem is that the heavy medium three-product hydrocyclone process for producing silicon coal increases the iron content of the silicon coal, making the product unsuitable as a carbonaceous reducing agent. Therefore, there has been a technical bias in the field that the heavy medium three-product hydrocyclone process is not suitable for producing silicon coal. Furthermore, those skilled in the art have long desired to utilize the heavy medium three-product hydrocyclone process to extract silicon coal, thereby improving the precision and yield of silicon coal products. Summary of the Invention

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a sorting process and system for coal used in multi-product chemical processing, achieving high-precision production of silicon coal.

[0006] To achieve the above objectives, embodiments of the present invention provide a sorting process for coal used in multi-product chemical processing, comprising the following steps: Main selection: The raw material is fed into the main selection heavy medium three-product hydrocyclone, and the main separation yields the main selected clean coal; Further separation: The main selected clean coal is fed into the three-product hydrocyclone of the secondary heavy medium separation, and then separated to obtain ultra-low ash clean coal. After the ultra-low ash clean coal undergoes pre-demediation, demediation by demediation screen, and dewatering and classification, silicon coal product is obtained. Among them, the pre-demediation of ultra-low ash clean coal is carried out in the arc screen of secondary clean coal separation, the demediation by demediation screen is carried out in the double-layer screen of secondary clean coal demediation, and the dewatering and classification is carried out in the silicon coal centrifugal dewatering machine. During the main sorting process, the sorting density is 1.4-1.6 g / cm³. 3 During re-sorting, the sorting density is 1.25-1.3 g / cm³. 3 .

[0007] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing, in which the main refined coal is fed into a three-product hydrocyclone for re-selection of heavy media, and the main refined coal first undergoes pre-demediation, demediation by demediation screen, dewatering and classification and mixing treatment in sequence; The process involves several steps: pre-demediation of the primary refined coal is carried out in a primary refined coal arc screen; demediation of the primary refined coal is carried out in a primary refined coal demediation screen; dewatering and classification of the primary refined coal is carried out in a primary refined coal centrifuge; and mixing of the primary refined coal with a low-density heavy medium suspension is carried out in a re-selection mixing tank. After dewatering and classification in the primary refined coal centrifuge, the primary refined coal is transferred to the re-selection mixing tank via a primary refined coal quantitative feeder and then pumped to the re-selection heavy medium three-product hydrocyclone via a mixing pump.

[0008] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing. The three-product hydrocyclone of the main heavy medium also separates the main medium coal and the main gangue. The main medium coal is pre-demediumed, demediumed by a demediuming screen and dewatered to obtain the mixed coal product. The main gangue is pre-demediumed, demediumed by a demediuming screen and dewatered to obtain the gangue product. The pre-demediation of the main medium is carried out in the main medium arc screen, the demediation of the main medium is carried out in the main medium demediation screen, and the dewatering of the main medium is carried out in the main medium centrifuge.

[0009] The pre-demediation of the main gangue is carried out in the main gangue arc screen, and the demediation and dewatering of the main gangue are carried out in the main gangue demediation screen.

[0010] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing. Before the raw material is fed into the main heavy medium three-product hydrocyclone, it is first deslimed by a desliming screen to obtain 1-25mm material. The 1-25mm material is fed into the main mixing tank and then into the main heavy medium three-product hydrocyclone by the main mixing pump. The main mixing tank is also pumped with the main qualified medium from the main qualified medium tank by the main mixing pump. The qualified medium from the main coal arc screen, main coal desliming screen, main medium coal arc screen, main medium coal desliming screen, main gangue arc screen and main gangue desliming screen is returned to the main qualified medium tank for recycling. The main coal desliming screen, the undersize medium of the main coal desliming screen, and part of the medium flowing out of the main coal arc screen are sent to the main coal fine-medium magnetic separator for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main coal fine qualified medium tank for recycling. The tailings of the main coal fine-medium magnetic separator are used as flushing water for the desliming screen. The dilute medium undersize from the main gangue desliming screen is fed into the main gangue magnetic separator for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main gangue qualified medium tank for recycling. The magnetic tailings from the main gangue magnetic separator enter the magnetic tailings tank. After being concentrated in stages by the thickener hydrocyclone, the underflow is recovered by the high-frequency screen, and the overflow enters the thickener. The centrifugal liquid from the main coal centrifuge and the centrifugal liquid from the main coal centrifuge enter the coal slime tank.

[0011] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing, in which the 0-1mm material obtained by the desliming screen enters the coal slime bucket when the raw material is deslimed by the desliming screen. The coal slurry in the coal slurry bucket is pumped to a coal slurry thickening and classifying hydrocyclone group for thickening and classification. The classification particle size is 0.25mm. The 1-0.25mm coarse coal slurry obtained from the underflow after classification is sent to a three-product interference bed separator for further classification. The clean coal separated by the three-product interference bed separator is then screened and dewatered by a clean coal slurry classifying and dewatering screen and a clean coal slurry centrifuge before being blended into coking coal products. Alternatively, the clean coal separated by the three-product interference bed separator can be blended into 0-3 mm ultra-low ash clean coal products; the middlings separated by the three-product interference bed separator are returned to the rewash mixing tank for rewashing; the gangue separated by the three-product interference bed separator and the magnetic tailings from the main gangue magnetic separator are dewatered together by the fine gangue high-frequency screen and then enter the gangue products or mixed coal products; the underflow from the fine gangue high-frequency screen enters the thickener; the underflow from the clean coal slime grading and dewatering screen and the centrifugal liquid from the clean coal slime centrifuge are sent to the coal slime bucket through the centrifugal liquid transfer pump.

[0012] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing. When the coal slime thickening and grading hydrocyclone group performs thickening and grading, the overflow fine coal slime material (0-0.25mm) is treated by stirring and adding reagents by the slurry preprocessor and then fed into a flotation machine for flotation separation. The flotation machine is a two-stage flotation machine, which performs two flotations. When only coking coal is produced, the high-ash tailings separated by the primary flotation enter the thickener, the concentrate is sent to the flotation concentrate bucket by secondary flotation, and then pumped to the flotation coal filter press by flotation concentrate pump. The flotation coal filter press dewaters the coal and produces coking coal product. The filtrate from the flotation coal filter press enters the thickener, and the tailings from the secondary flotation enter the thickener or are returned to the flotation machine for further flotation. When producing ultra-low ash clean coal and coking clean coal simultaneously, the tailings from the primary flotation enter the thickener, the concentrate from the secondary flotation is dewatered using a flotation clean coal filter press and used as ultra-low ash clean coal product, and the tailings from the secondary flotation are dewatered and used as coking coal product. The secondary flotation clean coal is mixed with 0-3mm ultra-low ash clean coal product.

[0013] The coal slurry water entering the thickener is concentrated, and the underflow from the thickener is pumped to the coal slurry filter press. After dewatering by the coal slurry filter press, the filter cake is used as the coal slurry product. The filtrate from the thickener is returned to the thickener, and the overflow from the thickener is used as circulating water in the circulating water tank. The circulating water is pumped to the required location by the circulating water pump.

[0014] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing. The main selected clean coal is fed into a three-product hydrocyclone for re-selection of heavy media. The re-selection of heavy products is further obtained. The re-selection of heavy products is pre-de-mediumized by a re-selection medium-gangue arc screen, de-mediumized by a re-selection of heavy products de-mediumized screen, and dewatered by a re-selection of heavy products centrifuge to obtain the re-selection of heavy products. The undersize medium from the double-layer screen for desliming the refined coal and the screen for desliming the heavy products is fed into the magnetic separator for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the qualified medium tank for recycling. When ultra-low ash clean coal is de-saturated in the double-layer screen for de-saturation of re-selected clean coal, the material on the upper screen is de-watered in the silicon clean coal centrifugal dewatering machine to obtain silicon coal product, and the material on the lower screen is de-watered in the re-selected coking coal centrifugal dewatering machine to obtain coking coal product. The qualified medium in the reselected qualified medium tank is then pumped into the reselected mixing tank via the reselected mixed medium pump.

[0015] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing. The upper screen surface of the double-layer screen for desliming refined coal is made of ceramic-metal composite material, with a nano-wear-resistant and anti-stick coating sprayed on the surface. The nano-wear-resistant and anti-stick coating contains graphite-modified particles to prevent iron ore magnetic powder from adsorbing onto the screen surface. At the same time, multiple sets of high-gradient permanent magnet strips are embedded and integrated inside the screen surface, with a magnetic field strength of 0.8-1.0T. The permanent magnet strips are arranged in a staggered and uniform manner with a spacing of 30-50mm. The magnetic field direction is perpendicular to the material movement direction, forming a transverse magnetic field gradient. The magnetic intensity of the permanent magnet strips is steplessly adjustable from 0.3-1.0T through a PLC control system. The screen surface is excited by dual-frequency vibration, with a vibration frequency of 50-60Hz and an amplitude adjustable from 0.5-1.5mm. The vibration direction is at a 45° angle to the material movement direction. The magnetic attraction of the built-in permanent magnet strips adsorbs and separates the coarse iron ore magnetic powder mixed on the material surface and in the gaps. The adsorbed magnetic powder is periodically scraped off to the upper collection tank by a built-in scraper device on the screen surface. The scraper device uses a flexible wear-resistant scraper.

[0016] For example, at least one embodiment of this disclosure provides a sorting process for coal used in multi-product chemical processing. The lower screen surface of the double-layer screen for desliming refined coal is divided into three adjacent sections: a front desliming zone, a middle deep magnetic separation zone, and a rear rinsing and desorption zone. The front desliming zone uses a fine, wear-resistant screen surface with a porosity of 35%–40%. The middle deep magnetic separation zone incorporates a superconducting magnetic separation module with a magnetic field strength of 1.5–2.0 T and a magnetic field gradient of 10 T / m³. The superconducting magnetic separation module consists of two layers: an upper layer with a magnetic field strength of 1.8–2.0 T and a lower layer with a magnetic field strength of 1.5–1.8 T. The magnetic flux is infinitely adjustable from 0 to 90° according to the material thickness. The online magnetic flux detection module monitors the changes in magnetic field strength in real time. When the magnetic flux fluctuation exceeds ±5%, magnetic field compensation is performed. The downstream rinsing and desorption zone is subjected to high-pressure spraying and ultrasonic vibration. The spraying pressure is 0.3-0.5MPa. The spraying water is recycled water that has been magnetized with a magnetization intensity of 0.2T. At the same time, a built-in 18kHz ultrasonic vibration device is used to destroy the adsorption force between the magnetic powder and the surface of the coal particles through ultrasonic vibration, thereby desorbing the residual trace magnetic powder. The desorbed fine magnetic powder particles fall into the lower collection tank. The upper screen of the double-layer screen for desliming of refined coal is equipped with a high-pressure desliming spray at a pressure of 0.5-0.6 MPa to wash away the large amount of heavy medium suspension adhering to the material surface; the lower screen is equipped with a medium-pressure rinsing spray at a pressure of 0.3-0.4 MPa to remove the magnetic powder remaining in the material gaps; and the lower screen is equipped with a low-pressure magnetizing spray at a pressure of 0.2-0.3 MPa. After the spray water is magnetized, it removes the trace magnetic powder adsorbed on the material surface. In addition to the built-in ultrasonic vibration device on the lower screen surface, high-frequency ultrasonic generators are additionally installed on both sides of the screen body box, and the ultrasonic vibration is transmitted to the entire screen surface through the box. A magnetic separation and recovery module with a magnetic field strength of 1.2T is installed in the grading and collection tank at the bottom of the screen body to perform secondary magnetic separation and purification on the collected coarse and fine magnetic powder. The purified magnetic powder is returned to the qualified medium tank for recycling through the conveying device, and the unqualified magnetic powder is sent to the magnetic separation tailings treatment system.

[0017] This invention also provides a sorting system for multi-product chemical coal, comprising a primary heavy medium three-product hydrocyclone and a secondary heavy medium three-product hydrocyclone connected in sequence.

[0018] Compared with the prior art, the separation process and system for multi-product chemical coal provided by the embodiments of the present invention have the following significant technical advantages: In response to the resource characteristics of raw coal, such as low ash and low sulfur content, and the new demands for clean and efficient utilization, the target clean coal ash content was achieved to be ≤3%, and the separation density (i.e., the density of the heavy medium suspension) was 1.25-1.3 g / cm³. 3 It is far lower than the 1.4-1.6 g / cm³ of coking coal and thermal coal.3 The conventional sorting density has a significant demonstration effect on the efficient and large-scale industrial production of ultra-low ash coal. The project results not only meet the construction and production needs of Xingmei Mining's clean and efficient coal preparation plant, but also have broad prospects for promotion and application.

[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are merely some exemplary embodiments of this application. For those skilled in the art, other drawings can be obtained based on the content of the exemplary embodiments of this application and these drawings without any creative effort.

[0021] Figure 1 This is a schematic diagram of a sorting system in one embodiment of the present invention; In the diagram: Desliming screen (1), main mixing tank (2), main mixing pump (3), main qualified medium tank (4), main mixed medium pump (5), main heavy medium three-product hydrocyclone (6), main gangue arc screen (7), main medium coal arc screen (8), main clean coal arc screen (9), main gangue desliming screen (10), main medium coal desliming screen (11), main clean coal desliming screen (12), main gangue magnetic separator (13), main clean and medium magnetic separator (14), main medium coal centrifuge (15), main clean coal centrifuge (16), main clean coal quantitative feeder (17), secondary heavy medium three-product hydrocyclone (18), secondary clean coal arc screen (19), secondary medium gangue arc screen (20), secondary clean coal desliming double-layer screen (21), secondary heavy product desliming screen (22), silicon clean coal centrifuge Dewatering machine (23), coking coal centrifuge (24), magnetic separator for re-selected products (25), centrifuge for re-selected heavy products (26), coal slime bucket (27), coal slime pump (28), re-selected mixing bucket (29), mixing pump (30), qualified medium bucket for re-selection (31), re-selected mixed medium pump (32), coal slime thickening and grading hydrocyclone group (33), three-product interference bed separator (34), fine coal slime grading and dewatering screen (35), fine gangue high frequency screen (36), fine coal slime centrifuge (37), centrifugal liquid transfer pump (38), flotation machine (39), flotation concentrate bucket (40), flotation concentrate pump (41), flotation fine coal filter press (42), coal slime filter press (43), thickener (44), thickener underflow pump (45), circulating water tank (46), circulating water pump (47). Detailed Implementation To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0022] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and they do not represent the actual structure of the product. Furthermore, for ease of understanding, in some figures, components with the same structure or function are shown only schematically, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0023] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] It should be noted that when an element is referred to as being "set on" another element, it can be directly set on the other element or indirectly set on the other element. It should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0025] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0026] Please see Figure 1 The present invention provides a sorting process for coal used in multi-product chemical processing, comprising the following steps: Main selection: The main selection of clean coal is fed into the main selection heavy medium three-product hydrocyclone 6, and the main separation yields the main selection of clean coal; Further separation: The main selected clean coal is fed into the three-product hydrocyclone 18 for further separation to obtain ultra-low ash clean coal. After pre-demediation, demediation by demediation screen, and dewatering, the ultra-low ash clean coal is used to obtain silicon coal product. Among them, the pre-demediation of ultra-low ash clean coal is carried out in the arc screen 19 of the re-selected clean coal, the demediation by demediation screen is carried out in the double-layer screen 21 of the re-selected clean coal, and the dewatering is carried out in the silicon coal centrifugal dewatering machine 23. During the main sorting process, the sorting density is 1.4-1.6 g / cm³. 3 During re-sorting, the sorting density is 1.25-1.3 g / cm³. 3 .

[0027] Before the main selected clean coal is fed into the three-product hydrocyclone 18 of the secondary heavy medium, the main selected clean coal first undergoes pre-demediation, demediation by demediation screen, dewatering and mixing treatment in sequence.

[0028] The primary refined coal undergoes pre-demediation, i.e., coarse demediation, in the primary refined coal arc screen 9; the primary refined coal demediation screen 12; the primary refined coal dewatering is carried out in the primary refined coal centrifuge 16; the primary refined coal is mixed with a low-density heavy medium suspension in the re-selection mixing tank 29; the primary refined coal is fed from the primary refined coal centrifuge 16 to the re-selection mixing tank 29 via the primary refined coal quantitative feeder 17; and the primary refined coal is then fed from the re-selection mixing tank 29 to the re-selection heavy medium three-product hydrocyclone 18 via the mixing pump 30.

[0029] The primary coal dewatering screen 12 has a 0.75mm screen opening. Material between 0.75mm and 25mm on the screen is dewatered by the primary coal centrifuge 16 and can be used as coking coal product, or it can be further separated in the secondary heavy medium hydrocyclone 6 to produce silicon coal product. The primary heavy medium hydrocyclone 6 is a pressurized heavy medium hydrocyclone, and the secondary heavy medium hydrocyclone 18 is also a pressurized heavy medium hydrocyclone. Follow these steps: Primary Selection Stage: Raw coal with low ash and low sulfur characteristics is selected as the raw material and fed into a pressurized primary heavy medium three-product hydrocyclone 6. The primary heavy medium three-product hydrocyclone 6 utilizes the centrifugal force generated by the heavy medium suspension for separation, with the separation density controlled at 1.4-1.6 g / cm³. During this process, the raw coal is separated in the heavy medium suspension according to density differences; the less dense portion becomes the primary clean coal, while the more dense portion is discharged as other products. For example, when the raw coal contains components such as coal gangue and clean coal of different densities, the primary heavy medium three-product hydrocyclone 6 can initially separate most of the clean coal, preparing for further purification. A portion of the primary clean coal can also be directly selected as coking coal products according to market demand.

[0030] In the main coal pretreatment stage, the main coal needs to undergo a series of pretreatment operations before entering the heavy medium three-product hydrocyclone 18.

[0031] Pre-demediation: The main refined coal first enters the main refined coal arc screen 9 for pre-demediation. The screen surface of the main refined coal arc screen 9 is arc-shaped, which can use centrifugal force to accelerate the separation of the medium and the refined coal. In this process, most of the heavy medium suspension is initially separated from the main refined coal, and the main refined coal is initially screened.

[0032] Desliming Screening: The pre-deslimed main coal enters the main coal desliming screen 12 for desliming. The main coal desliming screen 12 is a single-layer screen with a slit size of 0.75mm. The upper screen slits can screen out larger particles, and the material on the screen is dewatered by the main coal centrifuge 16 and can be used as coal product. The lower screen slits further screen smaller particles. The material on the screen with a 3-0.75mm slit is dewatered by the coal centrifuge and can be blended into coking coal product according to market demand, or it can be blended into 0-3mm ultra-low ash coal product. When there is a large market demand for ultra-low ash coal product, the upper screen plate of the coal desliming screen can be removed, so that the material on the screen with a 25-0.75mm slit is dewatered by the coal centrifuge and used as ultra-low ash coal product.

[0033] Dewatering: The main coal is dewatered in the main coal centrifuge 16 to remove most of the moisture, thereby improving the quality of the coal and the convenience of subsequent processing.

[0034] Mixing: The dewatered main selected clean coal is fed into the reselection mixing tank 29 through the main selected clean coal quantitative feeder 17. Low density heavy medium suspension is mixed in the reselection mixing tank 29. The mixed main selected clean coal is sent to the reselection heavy medium three-product hydrocyclone 18 through the mixing pump 30.

[0035] Re-selection stage: The main-selected clean coal enters a pressurized heavy medium three-product hydrocyclone 18 for further separation. The heavy medium three-product hydrocyclone 18 also utilizes the centrifugal force of the heavy medium suspension for finer separation, with the separation density controlled at 1.25-1.3 g / cm³. Within this density range, impurities in the main-selected clean coal can be further separated to obtain ultra-low ash clean coal.

[0036] Post-processing stage: The ultra-low ash clean coal obtained by re-selection is subjected to pre-demediation, demediation screening and dewatering treatment in sequence to finally obtain silicon coal product.

[0037] Pre-demediation: The ultra-low ash clean coal undergoes pre-demediation in the re-selection clean coal arc screen 19 to remove some larger particles of impurities or possible residual media blocks, thereby further purifying the ultra-low ash clean coal.

[0038] Demedium removal: The pre-demed ultra-low ash clean coal enters the double-layer demedium screen 21 for demedium removal. In this process, the heavy medium suspension in the ultra-low ash clean coal is completely removed and classified according to particle size.

[0039] Dehydration: Finally, the ultra-low ash coal is dehydrated in a silicon coal centrifugal dewatering machine 23 to remove the remaining moisture and obtain the final silicon coal product.

[0040] Through a two-stage heavy media hydrocyclone separation process involving primary and secondary selection, iron-containing minerals such as pyrite in raw coal can be effectively removed, reducing the iron content and ash content in silicon coal. The final silicon coal product has an ash content of ≤3%, meeting the stringent requirements for ash and iron content when used as a carbonaceous reducing agent, thus ensuring the quality of the silicon coal. Furthermore, low-ash coking coal with an ash content of ≤6% can also be produced, providing coal users with high-quality customized products and improving the quality of raw materials for coal chemical industry.

[0041] The use of a three-product heavy medium hydrocyclone process improves the recovery rate of both silicon coal and coking coal compared to traditional jigging and dry separation processes. Traditional processes result in low silicon coal recovery rates when processing difficult-to-process coal types, while this process fully utilizes the high-efficiency separation capacity of the three-product heavy medium hydrocyclone, reducing clean coal loss and improving economic efficiency.

[0042] This process creates a wide-range, multi-configuration coal washing system that can be adjusted in real time. It can achieve various production configurations based on production needs, including single-product coking coal blending, coking coal blending + silicon concentrate, and coking coal blending + silicon concentrate + ultra-low ash pure coal. For example, when market demand for coking coal is high, process parameters can be adjusted to increase the proportion of the main-selected concentrate directly used as coking coal product; when demand for silicon coal is strong, the process can be optimized to increase silicon coal production. This flexibility allows companies to better adapt to market changes and improve their market competitiveness.

[0043] In response to the resource characteristics of raw coal, such as low ash and low sulfur, and the new demands for clean and efficient utilization, research was conducted from multiple dimensions, including deep washing and beneficiation process research, key technology and equipment development, process parameter optimization, equipment performance improvement, and precise index control. This research broke through the technological bottlenecks in ultra-low ash clean coal washing and beneficiation, resulting in a refined coal preparation process package and complete set of technical equipment. For the first time in China, a demonstration coal preparation plant was built using a combined heavy medium-interference bed-flotation process to wash ultra-low ash clean coal and siliceous coal, with a target clean coal ash content ≤3% and a separation density (i.e., the density of the heavy medium suspension) of 1.25-1.3 g / cm³. 3 It is far lower than the 1.4-1.6 g / cm³ of coking coal and thermal coal. 3The conventional sorting density has a significant demonstration effect on the efficient and large-scale industrial production of ultra-low ash coal. The project results not only meet the construction and production needs of Xingmei Mining's clean and efficient coal preparation plant, but also have broad prospects for promotion and application.

[0044] Develop coal preparation processes for multiple products, including ultra-low ash coal and silicon coal, and build a clean and efficient coal preparation demonstration plant to produce ultra-low ash coal and silicon coal with ash content ≤3% and low ash coking coal with ash content ≤6%, providing customized products for coal users and improving the quality of coal chemical raw materials and the efficiency of clean conversion.

[0045] This real-time adjustable, wide-range, multi-configuration coal washing and beneficiation system enables extensive adjustment of clean coal indicators and can implement various production schemes according to production needs, such as single-product coking coal blending, coking coal blending + silicon coal, and coking coal blending + silicon coal + ultra-low ash pure coal. The system is highly efficient, flexible, and adaptable. The washing and beneficiation equipment in this invention uses a heavy media three-product hydrocyclone, which can improve the recovery rate of silicon coal and coking coal, while more effectively removing iron-containing minerals such as pyrite from the raw coal, reducing the iron content and ash content in the silicon coal, and ensuring the quality of the silicon coal.

[0046] In some examples, the primary heavy medium hydrocyclone 6 further separates primary medium coal and primary gangue. The primary medium coal is pre-demediumed, demediumed by a demediuming screen, and dewatered to obtain a mixed coal product. The primary gangue is pre-demediumed, demediumed by a demediuming screen, and dewatered to obtain a gangue product. Specifically, the pre-demediuming of the primary medium coal is carried out in the primary medium coal arc screen 8, the demediuming of the primary medium coal is carried out in the primary medium coal demedium screen 11, and the dewatering of the primary medium coal is carried out in the primary medium coal centrifuge 15. The pre-demediuming of the primary gangue is carried out in the primary gangue arc screen 7, and the demediuming and dewatering of the primary gangue are carried out in the primary gangue demedium screen 10.

[0047] Before the raw material is fed into the main heavy medium three-product hydrocyclone 6, it is first deslimed by the desliming screen 1 to obtain 1-25mm material. The 1-25mm material is fed into the main mixing tank 2 and then into the main heavy medium three-product hydrocyclone 6 by the main mixing pump 3. The main mixing tank 2 is also fed into the main qualified medium tank 4 by the main mixed medium pump 5.

[0048] The qualified medium under the screens of the main coal arc screen 9, the main coal desliming screen 12, the main coal arc screen 8, the main coal desliming screen 11, the main gangue arc screen 7, and the main gangue desliming screen 10 is returned to the main qualified medium tank 4 for recycling.

[0049] The undersize medium from the main coal desliming screen 12 and the main coal desliming screen 11, and part of the medium flowing out from the main coal arc screen 9 are sent to the main coal fine magnetic separator 14 for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main qualified medium tank 4 for recycling. The tailings of the main coal fine magnetic separator 14 are used as flushing water for the desliming screen 1.

[0050] The undersize medium from the main gangue desliming screen 10 is fed into the main gangue magnetic separator 13 for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main gangue qualified medium tank 4 for recycling. The magnetic tailings from the main gangue magnetic separator 13 enter the magnetic tailings tank. After being concentrated in stages by the thickener hydrocyclone, the underflow is recovered by the high-frequency screen, and the overflow enters the thickener 44. The centrifugal liquid from the main coal centrifuge 16 and the centrifugal liquid from the main coal centrifuge 15 enter the coal slime tank 27.

[0051] The screen openings of the main medium coal arc screen 8 and the main medium coal desliming screen 11 are 0.75mm. The separated main medium coal is deslimed and dewatered by the main medium coal arc screen 8 and the main medium coal desliming screen 11. The main medium coal desliming screen 11 is a single-layer screen with a screen opening of 0.75mm. The material on the screen is then dewatered by the main medium coal centrifuge 15 and used as mixed coal product. The separated main gangue is deslimed and dewatered by the main gangue arc screen 7 and the main gangue desliming screen 10 and used as gangue product.

[0052] The material is sprayed in the desliming screen. The screen surface is divided into two sections: the qualified section before spraying and the dilute medium section after spraying. The liquid medium flowing out of the qualified section is the qualified medium, and the liquid medium flowing out of the dilute medium section is the undersize dilute medium. The portion of the medium with higher coal slime content flowing out of the main coal arc screen 9 is sent to the main coal fine and medium magnetic separator 14, while the qualified medium with lower coal slime content flowing out is sent to the main qualified medium tank 4.

[0053] Please follow these steps: Crushing and Desliming: The raw coal is first crushed to reduce its particle size to less than 25mm, serving as the raw material for subsequent sorting. The crushed raw material is then fed into desliming screen 1 for desliming, which separates materials with a particle size of 1-25mm. This material enters the main selection mixing tank 2, while the qualified main selection medium from the qualified main selection medium tank 4 is also fed into the main selection mixing tank 2 via the main selection mixing pump 5, where it is thoroughly mixed with the 1-25mm material, preparing it for entry into the main selection heavy medium three-product hydrocyclone 6.

[0054] The main heavy medium three-product hydrocyclone separation process: The mixed material is pumped by the main mixing pump 3 into the pressurized main heavy medium three-product hydrocyclone 6 for main separation. During the main separation process, the raw material is separated into three products based on density differences: main separated clean coal, main separated medium coal, and main separated gangue. The separation density of the main separation is controlled at 1.4-1.6 g / cm³ to ensure effective separation of materials with different densities.

[0055] Primary Clean Coal Processing: After being discharged from the primary heavy medium three-product hydrocyclone 6, the primary clean coal first enters the primary clean coal arc screen 9 for pre-demediuming. During this process, most of the heavy medium suspension is initially separated from the clean coal, and the clean coal undergoes preliminary screening. Next, the primary clean coal enters the primary clean coal demediuming screen 12 for demediuming. The primary clean coal demediuming screen 12 is a double-layer screen. The upper screen has a 3mm gap; the material on the upper screen, after dewatering by the primary clean coal centrifuge 16, can be used as silicon coal product. The lower screen has a 0.75mm gap; the material on the lower screen, with a 3-0.75mm gap, after dewatering by the clean coal centrifuge, can be blended with coking coal product or 0-3mm ultra-low ash clean coal product according to market demand. When there is a high market demand for ultra-low ash clean coal product, the upper screen plate of the clean coal demediuming screen is removed, and the material on the upper screen, with a 25-0.75mm gap, is dewatered by the clean coal centrifuge and used as ultra-low ash clean coal product. The portion of the medium with higher coal slime content that flows out from the main coal slurry arc screen 9 is sent to the main coal slurry magnetic separator 14, while the qualified medium with lower coal slime content that flows out is sent to the main coal slurry qualified medium tank 4 for recycling. The dilute medium under the main coal slurry desliming screen 12 and a portion of the medium flowing out from the main coal slurry arc screen 9 are sent to the main coal slurry magnetic separator 14 for magnetic separation. The magnetically separated concentrate is returned to the main coal slurry qualified medium tank 4 for recycling, and the tailings from the magnetic separator are used as flushing water for the desliming screen 1. The centrifugal liquid from the main coal slurry centrifuge 16 enters the coal slime tank 27.

[0056] Medium Coal Processing: After being discharged from the main medium heavy medium three-product hydrocyclone 6, the medium coal undergoes pre-desmuthing treatment via the main medium coal arc screen 8, desmuthing via the main medium coal desmuthing screen 11, and dewatering via the main medium coal centrifuge 15, before being processed into mixed coal product. The screen openings of both the main medium coal arc screen 8 and the main medium coal desmuthing screen 11 are 0.75mm, with the main medium coal desmuthing screen 11 being a single-layer screen. After desmuthing and dewatering, the material oversize from the main medium coal desmuthing screen 11 is further dewatered via the main medium coal centrifuge 15 before being processed into coking coal product. The qualified medium undersize from the main medium arc screen 9, main medium medium desmuthing screen 12, main medium coal arc screen 8, and main medium coal desmuthing screen 11 is returned to the main medium qualified medium tank 4 for recycling. The undersize medium from the main coal desliming screen 12 and the main medium coal desliming screen 11, along with a portion of the medium flowing out from the main coal arc screen 9, are fed into the main coal fine-medium magnetic separator 14 for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main coal qualified medium tank 4 for recycling. The tailings from the main coal fine-medium magnetic separator 14 are used as flushing water for the desliming screen 1. The centrifugal liquid from the main coal fine-medium centrifuge 15 enters the coal slime tank 27.

[0057] Main gangue processing: After being discharged from the main heavy medium three-product hydrocyclone 6, the main gangue sequentially passes through the main gangue arc screen 7 for pre-desliming, and the main gangue desliming screen 10 for desliming and dewatering. The dilute medium undersize from the main gangue desliming screen 10 is fed into the main gangue magnetic separator 13 for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main gangue qualified medium tank 4 for recycling. The magnetic tailings from the main gangue magnetic separator 13 enter the magnetic tailings tank, and after being concentrated by the thickening hydrocyclone, the underflow is recovered by the high-frequency screen, and the overflow enters the thickener 44. The qualified medium undersize from the main gangue arc screen 7 and the main gangue desliming screen 10 is returned to the main gangue qualified medium tank 4 for recycling.

[0058] Re-selection of three-product heavy media hydrocyclone: ​​The pretreated main-selected clean coal is fed into the re-selection mixing tank 29 via the main-selected clean coal quantitative feeder 17. After being mixed with a low-density heavy medium suspension in the re-selection mixing tank 29, it is sent by the mixing pump 30 into the pressurized re-selection three-product heavy medium hydrocyclone 18 for re-separation. The re-selection density is controlled at 1.25-1.3 g / cm³, further separating ultra-low ash clean coal.

[0059] Ultra-low ash clean coal processing: The ultra-low ash clean coal obtained from the re-selection process is sequentially screened in the re-selection clean coal arc screen 19 to remove larger particulate impurities; it is then de-mediumed in the re-selection clean coal de-medium double-layer screen 21 to completely remove heavy medium suspension and classify it; and finally dewatered in the silicon clean coal centrifugal dewatering machine 23 to obtain silicon coal product.

[0060] This process, through primary and secondary selection stages, can produce a variety of products to meet different needs, including silicon coal products, coking coal products, blended coal products, and gangue products, achieving refined utilization of coal resources. The ash content of different products is strictly controlled; for example, the ash content of silicon coal products is ≤3%, and the ash content of low-ash coking coal is ≤6%, meeting the quality requirements of raw coal for different chemical industries.

[0061] The heavy media hydrocyclone process effectively removes iron-containing minerals such as pyrite from raw coal, reducing the iron content in silicon coal and simultaneously lowering ash content, thus ensuring the quality of silicon coal as a carbonaceous reducing agent. Throughout the process, multiple demediuming, dewatering, and magnetic separation operations further purify the product and improve its quality stability.

[0062] The qualified media that passes through each desliming screen is returned to the main qualified media tank 4 for recycling, reducing media consumption. The main fine and medium magnetic separator 14 and the main gangue magnetic separator 13 perform magnetic separation on the dilute media, recovering the magnetic materials as magnetic concentrate and returning them to the main qualified media tank 4, thereby improving the media recovery rate and reducing production costs.

[0063] The tailings from the main fine magnetic separator 14 are used as flushing water for the desliming screen 1, realizing the recycling of water resources; the tailings from the main gangue magnetic separator 13 are concentrated in stages by a hydrocyclone, and the underflow is recovered by a high-frequency screen, while the overflow enters the thickener 44, reducing the discharge of solid waste, improving resource utilization, and having good environmental benefits.

[0064] In some examples, when the raw material is deslimed by the desliming screen 1, the 0-1mm material obtained from the desliming screen enters the coal slime bucket 27.

[0065] The coal slurry in the coal slurry bucket 27 is pumped by the coal slurry pump 28 to the coal slurry thickening and classifying hydrocyclone group 33 for thickening and classification. The classification particle size is 0.25mm. The 1-0.25mm coarse coal slurry obtained from the classification is sent to the three-product interference bed separator 34 for classification. The clean coal separated by the three-product interference bed separator 34 is screened and dewatered by the clean coal slurry classifying and dewatering screen 35 and the clean coal slurry centrifuge 37 and then blended into coking coal products. Alternatively, the clean coal separated by the three-product interference bed separator 34 can be blended with 0-3mm ultra-low viscosity coal. The middlings separated by the three-product interference bed separator 34 are returned to the rewash mixing tank for rewashing. The gangue separated by the three-product interference bed separator 34 and the magnetic tailings of the main gangue magnetic separator 13 are dewatered by the fine gangue high-frequency screen 36 and then enter the gangue product or mixed coal product. The underflow from the fine gangue high-frequency screen 36 enters the thickener 44. The underflow from the fine coal slime grading and dewatering screen 35 and the centrifugal liquid from the fine coal slime centrifuge 37 are sent to the coal slime bucket 27 through the centrifugal liquid transfer pump 38.

[0066] Material of 1-0.25mm is partially returned to the mixing tank 29 for use as coal slime; the amount of returned coal slime needs to be easily adjustable. The desliming screen 1 has a 1mm screen opening. The three-product interference bed separator 34 is abbreviated as TPS, and the fine coal slime grading and dewatering screen 35 is abbreviated as EPS.

[0067] When the coal slime thickening and classifying hydrocyclone group 33 is thickening and classifying, the overflow fine coal slime is 0-0.25mm material, which is fed into the flotation machine 39 for flotation after passing through the slurry preprocessor. The flotation machine 39 is a two-stage flotation machine, which performs two flotations. When only coking coal is produced, the high-ash tailings separated by the primary flotation enter the thickener 44, the concentrate is sent to the flotation concentrate bucket 40 by secondary flotation, and then sent to the flotation coal filter press 42 by the flotation concentrate pump 41. The flotation coal filter press 42 dewaters the coal and produces coking coal product. The filtrate from the flotation coal filter press 42 enters the thickener 44, and the tailings from the secondary flotation enter the thickener 44 or are returned to the flotation machine 39 for further flotation. When producing ultra-low ash clean coal and coking clean coal simultaneously, the tailings from the primary flotation enter the thickener 44, and the concentrate from the secondary flotation is dewatered using the flotation clean coal filter press 42 to become ultra-low ash clean coal products. The tailings from the secondary flotation are dewatered to become coking coal products, and the secondary flotation clean coal is mixed with 0-3mm ultra-low ash clean coal products.

[0068] The coal slurry water entering the thickener 44 is concentrated, and the underflow of the thickener 44 is sent to the coal slurry filter press 43 through the thickener underflow pump 45. After dewatering by the coal slurry filter press 43, the filter cake is used as the coal slurry product. The filtrate of the thickener 44 is returned to the thickener 44, and the overflow of the thickener 44 is used as circulating water in the circulating water tank 46. The circulating water is pumped to the required location through the circulating water pump 47.

[0069] Flotation machine 39 is a "3+2" type mechanically agitated flotation machine, which is an integrated mechanically agitated flotation device with 3 roughing cells connected in series with 2 cleaning cells. Fine coal slime first enters the 3 roughing cells to complete the first flotation, and the separated high-ash tailings are directly fed into the thickener. The roughing concentrate enters the 2 cleaning cells to complete the second flotation. The second flotation concentrate is dewatered by a filter press and then mixed with coking coal products. The second flotation tailings can be returned to the front end of the roughing cells for further flotation or directly fed into the thickener. It can also produce qualified clean coal and high-ash tailings in one flotation. The single-stage and double-stage flotation can be flexibly switched as needed.

[0070] When simultaneously producing ultra-low ash clean coal and coking coal, primary flotation ensures tailings ash content. Raw coal is crushed to below 25mm; 25-0mm raw coal undergoes 1mm desliming; 25-1mm raw coal is separated using a main separation pressurized three-product hydrocyclone; main separation clean coal undergoes secondary separation pressurized three-product hydrocyclone; 25-1mm coarse coal slime is separated using a three-product TPS separation; and 0-0.25mm fine coal slime utilizes a combined process of secondary flotation, tailings thickening, and pressure filtration. The entire plant achieves closed-loop wastewater circulation. This process is flexible and comprehensive, allowing for adaptability to different production methods based on product structure requirements and coal quality variations, enabling the production of various product structures such as ultra-low ash clean coal, silicon coal, and coking coal.

[0071] The main refined coal is de-mediumed twice, through the main refined coal arc screen 9 and the main refined coal de-mediuming screen 12, and then dewatered in the main refined coal centrifuge 16. It can also be mixed with the product obtained after separation by the three-product hydrocyclone 18 of the secondary heavy medium, de-mediumed by the secondary heavy product de-mediuming screen 22 and dewatered by the secondary heavy product centrifuge 26, as well as the coarse refined coal product obtained by the interfering bed separator 34 and the flotation refined coal obtained by the flotation machine 39. After dewatering by the flotation refined coal filter press 42, the flotation refined coal product is mixed with the flotation refined coal product to produce coking coal product.

[0072] Please follow these steps: Crushing and Preliminary Screening: Raw coal is crushed to a particle size of less than 25mm, serving as the raw material for the entire sorting process. The crushed raw coal enters desliming screen 1, with a screen opening of 1mm, to deslim the raw coal, separating 1-25mm material and 0-1mm material. The 1-25mm material enters the main selection mixing tank 2, while the qualified main selection medium from the qualified main selection medium tank 4 is also sent to the main selection mixing tank 2 via the main selection mixing pump 5. After thorough mixing, the two are sent by the main selection mixing pump 3 to the main selection heavy medium three-product hydrocyclone 6 for main selection. The 0-1mm material is directly sent to the coal slime tank 27.

[0073] Three-product hydrocyclone separation of primary heavy media: In the primary heavy media three-product hydrocyclone 6, the mixture is separated into three main products based on density differences: primary clean coal, primary medium coal, and primary gangue. The separation density in the primary separation process is controlled at 1.4-1.6 g / cm³.

[0074] Subsequent processing of the primary refined coal: The primary refined coal undergoes two desliming processes, passing through a primary refined coal arc screen 9 and a primary refined coal desliming screen 12. The primary refined coal arc screen 9 initially separates most of the heavy medium suspension and performs preliminary screening of the refined coal. The primary refined coal desliming screen 12 is a single-layer screen with a 3mm screen opening on the upper layer. The material on this screen, after dewatering by the primary refined coal centrifuge 16, can be used as silicon coal product. The lower screen opening is 0.75mm. The material on this screen, ranging from 0.75mm to 25mm, is dewatered by the refined coal centrifuge and can be blended into coking coal product or 0-3mm ultra-low ash refined coal product, depending on market demand. When there is a high market demand for ultra-low ash refined coal, the upper screen plate of the refined coal desliming screen is removed, and the material on this screen, ranging from 0.75mm to 25mm, is dewatered by the refined coal centrifuge and used as ultra-low ash refined coal product. The portion of the medium with higher coal slime content that flows out from the main coal slurry arc screen 9 is sent to the main coal slurry magnetic separator 14, while the qualified medium with lower coal slime content that flows out is sent to the main coal slurry qualified medium tank 4 for recycling. The undersize medium from the main coal slurry desliming screen 12 and a portion of the medium flowing out from the main coal slurry arc screen 9 are sent to the main coal slurry magnetic separator 14 for magnetic separation. The magnetically separated concentrate is returned to the main coal slurry qualified medium tank 4, and the tailings from the magnetic separator are used as flushing water for the desliming screen 1. The centrifugal liquid from the main coal slurry centrifuge 16 enters the coal slime tank 27.

[0075] Subsequent processing of main medium coal: The main medium coal is deslimed by passing it through the main medium coal arc screen 8 and the main medium coal desliming screen 11. Both screens have a gap of 0.75mm, and the main medium coal desliming screen 11 is a single-layer screen. The oversize material after desliming is then dewatered by the main medium coal centrifuge 15 and used as a mixed coal product. The qualified medium under the main medium arc screen 9, main medium coal desliming screen 12, main medium coal arc screen 8, and main medium coal desliming screen 11 is returned to the main medium qualified medium tank 4 for recycling. The dilute medium under the main medium desliming screen 12 and main medium coal desliming screen 11 and part of the medium flowing out of the main medium arc screen 9 are sent to the main medium magnetic separator 14 for magnetic separation. The magnetically separated concentrate is returned to the main medium qualified medium tank 4, and the tailings of the magnetic separator are used as flushing water for the desliming screen 1. The centrifugal liquid from the main medium coal centrifuge 15 enters the coal slime tank 27.

[0076] Subsequent processing of primary gangue: The primary gangue is sequentially passed through the primary gangue arc screen 7 and the primary gangue desliming screen 10 for desliming and dewatering. The dilute medium undersize from the primary gangue desliming screen 10 is fed into the primary gangue magnetic separator 13 for magnetic separation. The magnetic concentrate is returned to the primary gangue qualified medium tank 4 for recycling. The magnetic tailings enter the magnetic tailings tank, and after being fractionally concentrated by a hydrocyclone, the underflow is recovered through a high-frequency screen, and the overflow enters the thickener 44. The qualified medium undersize from the primary gangue arc screen 7 and the primary gangue desliming screen 10 is returned to the primary gangue qualified medium tank 4 for recycling.

[0077] Coal slime thickening and classification: The coal slime water in the coal slime bucket 27 is sent to the coal slime thickening and classification hydrocyclone group 33 by the coal slime pump 28 for thickening and classification, with a classification particle size of 0.25mm. This yields coarse coal slime of 1-0.25mm, which is then sent to the three-product interference bed separator 34 (TPS) for separation. Simultaneously, the overflow from the coal slime thickening and classification hydrocyclone group 33 is sent to the slurry preprocessor to obtain fine coal slime of 0-0.25mm, which is then sent to the flotation machine 39 for flotation.

[0078] Three-product interference bed separator: The three-product interference bed separator 34 separates coarse coal slime of 1-0.25mm. The separated clean coal is dewatered by the clean coal slime grading and dewatering screen 35 (EPS) and the clean coal slime centrifuge 37. It can be blended into coking coal products or 0-3mm ultra-low ash clean coal products. The middlings obtained from the separation are returned to the rewashing mixing tank for rewashing. The gangue, together with the magnetic tailings from the main gangue magnetic separator 13, is dewatered by the fine gangue high-frequency screen 36 and then enters the gangue products or mixed coal products. The underflow from the fine gangue high-frequency screen 36 enters the thickener 44. The underflow from the clean coal slime grading and dewatering screen 35 and the centrifugal liquid from the clean coal slime centrifuge 37 are sent to the coal slime bucket 27 by the centrifugal liquid transfer pump 38. In addition, the 1-0.25mm material is partially returned to the remixing tank 29 for use as coal slime, and the amount of returned coal slime can be easily adjusted.

[0079] Flotation: Flotation machine 39 is a "3 + 2" type mechanically agitated flotation machine, that is, an integrated mechanically agitated flotation device with 3 roughing cells connected in series with 2 cleaning cells. Fine coal slime first enters the 3 roughing cells to complete one flotation. When only coking coal is produced, the high-ash tailings separated by the first flotation enter the thickener 44, and the concentrate enters the 2 cleaning cells for a second flotation. The second flotation concentrate is sent to the flotation concentrate bucket 40, and then sent to the flotation concentrate filter press 42 by the flotation concentrate pump 41. After dewatering by the flotation concentrate filter press 42, it is used as the coking coal product. The filtrate of the flotation concentrate filter press 42 enters the thickener 44, and the tailings from the second flotation enter the thickener 44, or are returned to flotation machine 39 for a second flotation. When producing ultra-low ash clean coal and coking clean coal simultaneously, the tailings from the primary flotation enter the thickener 44, and the concentrate from the secondary flotation is dewatered using the flotation clean coal filter press 42 to become ultra-low ash clean coal product. The tailings from the secondary flotation are dewatered to become coking coal product, and the secondary flotation clean coal is mixed with 0-3mm ultra-low ash clean coal product.

[0080] Re-selection of three-product heavy media hydrocyclone: ​​Before entering the re-selection three-product heavy media hydrocyclone 18, the main selected clean coal undergoes pre-demediation steps such as pre-demediation via the main selected clean coal arc screen 9, demediation via the main selected clean coal demediation screen 12, dewatering via the main selected clean coal centrifuge 16, and mixing with a low-density heavy media suspension in the re-selection mixing tank 29. Afterwards, it is pumped by the mixing pump 30 into the re-selection three-product heavy media hydrocyclone 18 for re-selection. The re-selection density is controlled at 1.25-1.3 g / cm³, yielding ultra-low ash clean coal.

[0081] Post-processing of ultra-low ash clean coal: The ultra-low ash clean coal is sequentially screened in the re-selected clean coal arc screen 19, de-mediumed in the re-selected clean coal de-medium double-layer screen 21, and dewatered in the silicon clean coal centrifugal dewatering machine 23 to finally obtain silicon coal product.

[0082] Closed-loop circulation of wash water: The coal slurry water entering the thickener 44 is concentrated, and the underflow from the thickener 44 is sent to the coal slurry filter press 43 via the thickener underflow pump 45. After dewatering in the coal slurry filter press 43, the filter cake is used as the coal slurry product. The filtrate from the thickener 44 is returned to the thickener 44, and the overflow from the thickener 44 is sent to the circulating water tank 46 for use as circulating water. The circulating water is pumped to the required locations via the circulating water pump 47, realizing a closed-loop circulation of wash water throughout the plant.

[0083] Product Mixing: After being desaturated twice by the main selected clean coal arc screen 9 and the main selected clean coal desaturation screen 12, the main selected clean coal centrifuge 16 is dewatered. It can be mixed with the product of the re-selected heavy medium three-product hydrocyclone 18 after being desaturated by the re-selected heavy product desaturation screen 22 and dewatered by the re-selected heavy product centrifuge 26, as well as the coarse clean coal product obtained by the interfering bed separator 34 and the flotation clean coal product obtained by the flotation machine 39 after being dewatered by the flotation clean coal filter press 42 to produce coking coal product.

[0084] This process can flexibly produce various products such as ultra-low ash coal, silicon coal, and coking coal according to market demand. By employing different sorting processes for coal with different particle sizes, it achieves refined and efficient utilization of coal resources, meeting the diverse raw coal needs of different sectors of the chemical industry.

[0085] Each sorting stage works in close coordination, from primary sorting to secondary sorting, from coal slime treatment to post-processing, with strict quality control at every stage. For example, the heavy medium three-product hydrocyclone process effectively reduces the iron content and ash content in silicon coal, while the three-product interference bed separator and flotation machine further improve the quality of clean coal by treating coal slime, ensuring that the final product meets the corresponding quality standards.

[0086] Throughout the process, the qualified media that pass through each desliming screen and the magnetic concentrate recovered by magnetic separation are returned to the main qualified media tank 4 for recycling, which greatly reduces media consumption, improves resource utilization, and reduces production costs.

[0087] Closed-loop recycling of wash water: Through the synergistic action of equipment such as thickeners and filter presses, a closed-loop recycling of wash water is achieved, reducing water waste and sewage discharge, and providing good environmental benefits.

[0088] The flotation machine can flexibly switch between single-stage and double-stage flotation modes according to production needs. Furthermore, when producing different product structures, the product flow and processing methods at each stage can be adjusted accordingly. For example, when market demand differs for ultra-low ash coal and coking coal, the application and processing methods of the flotation products can be flexibly adjusted to meet market changes.

[0089] This process can adapt to raw coal of different qualities. By adjusting the parameters of each sorting device, such as the sorting density of the heavy medium three-product hydrocyclone and the operating conditions of the three-product interference bed separator, it can effectively cope with fluctuations in coal quality and ensure the stability of product quality.

[0090] In some examples, the main selected clean coal is fed into the three-product hydrocyclone 18 for further separation to obtain the re-selected heavy product. The re-selected heavy product is pre-de-mediumized by the re-selected gangue arc screen 20, de-mediumized by the re-selected heavy product de-mediumizing screen 22, and dewatered by the re-selected heavy product centrifuge 26 to obtain the re-selected heavy product product.

[0091] The undersize medium from the double-layer screen 21 for desliming refined coal and the screen 22 for desliming heavy products is fed into the magnetic separator 25 for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the qualified medium tank 31 for recycling.

[0092] When ultra-low ash clean coal is de-saturated in the double-layer screen 21 for re-selected clean coal, the material on the upper screen is dewatered in the silicon clean coal centrifugal dewatering machine 23 to obtain silicon coal product, and the material on the lower screen is dewatered in the coking coal centrifugal dewatering machine 24 to obtain coking coal product.

[0093] The qualified medium (reselected medium) in the qualified medium tank 31 is sent to the reselected mixing tank 29 through the reselected mixing pump 32. The upper screen of the double-layer screen 21 for reselecting clean coal desliming has a screen gap of 3mm and the lower screen has a screen gap of 0.75mm.

[0094] Follow these steps: Pre-demediation: After the main coal is re-separated in the three-product hydrocyclone 18 of the re-separation heavy medium, the resulting re-separated heavy product first enters the re-separation gangue arc screen 20 for pre-demediation. The re-separation gangue arc screen 20 uses centrifugal force and the action of the screen surface to initially separate most of the heavy medium suspension from the re-separated heavy product, and at the same time performs preliminary screening of the re-separated heavy product to remove some larger particles of impurities or media lumps that may adhere.

[0095] Desliming and dehydration: The reselected heavy product, after pre-desliming, then enters the reselected heavy product desliming screen 22 for desliming. The reselected heavy product desliming screen 22 further separates the remaining heavy medium suspension from the reselected heavy product. Subsequently, the reselected heavy product enters the reselected heavy product centrifuge 26 for dehydration to remove moisture, finally obtaining the reselected heavy product product.

[0096] Magnetic separation recovery medium: The dilute medium under the double-layer screen 21 for desliming the re-selected clean coal and the screen 22 for desliming the re-selected heavy products contains a certain amount of magnetic medium particles, which are fed into the magnetic separator 25 for magnetic separation. Under the action of the magnetic field, the magnetic medium particles are adsorbed and collected to form magnetic concentrate, while other impurities are discharged as tailings. The magnetic concentrate is returned to the qualified re-selection medium tank 31 for recycling, effectively improving the recovery rate of the medium and reducing production costs.

[0097] Medium supply and circulation: The reselected medium in the qualified medium tank 31 is sent to the reselected mixing tank 29 through the reselected mixing pump 32, and mixed with the pretreated main coal to provide a suitable heavy medium suspension for the next round of reselection process, ensuring the normal operation of the reselected heavy medium three-product hydrocyclone 18.

[0098] Desliming and Product Separation: Ultra-low ash clean coal undergoes desliming in a double-layer desliming screen 21 for re-selected clean coal. The upper screen opening of the double-layer desliming screen 21 is 3mm, and the lower screen opening is 0.75mm. The material oversized from the upper screen is dewatered in a siliceous coal centrifugal dewatering machine 23 to obtain siliceous coal product. The material oversized from the lower screen is dewatered in a coking coal centrifuge 24 to obtain coking coal product. This grading process can further separate ultra-low ash clean coal into different products according to the particle size and quality requirements of the product, meeting the market demand for coal products of different specifications.

[0099] By separately processing the reselected heavy products and classifying the ultra-low ash clean coal, the product range has been further enriched. In addition to the original products such as silicon coal and coking coal, reselected heavy products have also been obtained, and coking coal products of different specifications can be separated from ultra-low ash clean coal according to particle size differences, thereby improving the comprehensive utilization value of coal resources.

[0100] The refined processing of reselected heavy products and ultra-low ash clean coal helps to further improve product quality. Through multiple demediuming and dewatering operations, the residual media and moisture content in the product are reduced, thereby improving the purity and quality stability of the product.

[0101] By using the magnetic separator 25 to re-select the dilute medium for magnetic separation and recycling, the magnetic concentrate is returned to the qualified medium tank 31 for recycling, which greatly improves the utilization rate of the medium, reduces the loss and replenishment of the medium, and thus effectively controls the production cost.

[0102] The inclusion of the qualified medium tank 31 and the reselection medium pump 32 ensures a stable and suitable supply of heavy medium suspension during the reselection process, thereby guaranteeing the separation effect and product quality stability of the reselection heavy medium three-product hydrocyclone 18.

[0103] In some examples, the upper screen surface of the double-layer screen 21 for desliming refined coal is made of ceramic-metal composite material, with a nano-wear-resistant and anti-stick coating sprayed on the surface. Graphite-modified particles are added to this nano-wear-resistant and anti-stick coating to prevent iron ore magnetic powder from adsorbing onto the screen surface. Simultaneously, multiple sets of high-gradient permanent magnet strips are embedded and integrated inside the screen surface, with a magnetic field strength of 0.8-1.0T. The permanent magnet strips are arranged in a staggered, uniform pattern with a spacing of 30-50mm, and the magnetic field direction is perpendicular to the material movement direction, forming a transverse magnetic field gradient. The magnetic strips are controlled by a PLC system to achieve stepless adjustment of magnetic strength from 0.3 to 1.0T; the screen surface is excited by dual-frequency vibration, with a vibration frequency of 50-60Hz and an amplitude adjustable from 0.5 to 1.5mm. The vibration direction is at a 45° angle to the material movement direction. The built-in permanent magnet strips are used to adsorb and separate coarse iron ore magnetic powder mixed on the surface and in the gaps of the material. The adsorbed magnetic powder is periodically scraped off to the upper collection tank by a built-in scraper device on the screen surface. The scraper device uses a flexible wear-resistant scraper.

[0104] The lower screen surface of the double-layer screen 21 for desliming refined coal is divided into three adjacent sections: a front desliming zone, a middle deep magnetic separation zone, and a rear rinsing and desorption zone. The front desliming zone uses a fine, wear-resistant screen surface with a porosity of 35%–40%. The middle deep magnetic separation zone incorporates a superconducting magnetic separation module with a magnetic field strength of 1.5–2.0 T and a magnetic field gradient of 10 T / m³. The superconducting magnetic separation module consists of two layers: an upper layer with a magnetic field strength of 1.8–2.0 T and a lower layer with a magnetic field strength of 1.5–1.8 T. The direction is infinitely adjustable from 0-90° according to the material thickness. The online magnetic flux detection module monitors the changes in magnetic field strength in real time, and performs magnetic field compensation when the magnetic flux fluctuation exceeds ±5%. The downstream rinsing and desorption zone is subjected to high-pressure spraying and ultrasonic vibration. The spraying pressure is 0.3-0.5MPa, and the spraying water is magnetized circulating water with a magnetization intensity of 0.2T. At the same time, a built-in 18kHz ultrasonic vibration device is used to destroy the adsorption force between the magnetic powder and the surface of the coal particles through ultrasonic vibration, thereby desorbing the residual trace magnetic powder. The desorbed fine magnetic powder particles fall into the lower collection tank.

[0105] The upper screen of the double-layer screen 21 for desliming coal is equipped with a high-pressure desliming spray at a pressure of 0.5-0.6 MPa to wash away the large amount of heavy medium suspension adhering to the material surface; the lower screen is equipped with a medium-pressure rinsing spray at a pressure of 0.3-0.4 MPa to remove the magnetic powder remaining in the material gaps; and the lower screen is equipped with a low-pressure magnetizing spray at a pressure of 0.2-0.3 MPa. After the spray water is magnetized, it removes the trace magnetic powder adsorbed on the material surface.

[0106] In addition to the built-in ultrasonic vibration device on the lower screen surface, high-frequency ultrasonic generators are additionally installed on both sides of the screen body box, and the ultrasonic vibration is transmitted to the entire screen surface through the box. A magnetic separation and recovery module with a magnetic field strength of 1.2T is set in the grading and collection tank at the bottom of the screen body to perform secondary magnetic separation and purification on the collected coarse and fine magnetic powder. The purified magnetic powder is returned to the qualified medium tank 31 for recycling through the conveying device, and the unqualified magnetic powder is sent to the magnetic separation tailings treatment system.

[0107] The nano-wear-resistant and non-stick coating incorporates graphite-modified particles to prevent iron ore magnetic powder from adsorbing onto the screen surface; the permanent magnet strips can achieve stepless adjustment of magnetic strength from 0.3 to 1.0T via a PLC control system, automatically switching the magnetic strength level according to the magnetic powder content in the material; the dual-frequency vibration excitation of the screen surface can achieve both graded conveying of materials and vibration to shake off large pieces of iron ore magnetic powder adhering to the material; the flexible wear-resistant scraper has a ≥99% fit with the screen surface, and the scraping speed of the upper collection trough is linked and matched with the vibration frequency of the screen surface, specifically for collecting coarse magnetic powder particles.

[0108] The screen porosity of the desizing zone in the front section is 35%-40%, which enhances the channel for removing fine magnetic powder particles; the upper magnetic field strength is 1.8-2.0T, which is used to adsorb fine magnetic powder particles; the lower magnetic field strength is 1.5-1.8T, which is used to adsorb trace amounts of residual magnetic powder; the spray water uses magnetized circulating water with a magnetization intensity of 0.2T, which enhances the desorption capacity of magnetic powder; the lower collection tank is specifically for collecting fine magnetic powder particles.

[0109] The upper screen of the double-layer screen 21 for desliming coal is equipped with a high-pressure desliming spray at a pressure of 0.5-0.6 MPa to quickly rinse away the large amount of heavy medium suspension adhering to the material surface. The lower screen is equipped with a medium-pressure rinsing spray at a pressure of 0.3-0.4 MPa to remove residual magnetic powder in the material gaps. The lower screen is equipped with a low-pressure magnetizing spray at a pressure of 0.2-0.3 MPa. After being magnetized, the spray water can specifically remove trace amounts of magnetic powder adsorbed on the material surface. At the same time, the spray water adopts a closed-loop circulation system and is reused after magnetic separation and filtration, reducing water consumption and preventing magnetic powder from being lost with wastewater. In addition to the built-in ultrasonic vibration device on the lower screen surface, high-frequency ultrasonic generators are additionally installed on both sides of the screen body. The ultrasonic vibration is transmitted to the entire screen surface through the box, forming a combination of overall and local ultrasonic waves. This can not only destroy the adsorption force between magnetic powder and coal particles, but also prevent magnetic powder from clogging the screen gaps. At the same time, the ultrasonic frequency and the screen surface vibration frequency are linked and controlled. The ultrasonic power and vibration frequency are automatically adjusted according to the magnetic powder content in the material, so as to achieve synergistic optimization of desliming effect and energy saving.

[0110] The double-layer screen 21 for refining coal desliming improves the removal rate of iron ore magnetic powder by more than 15% compared to conventional structures. The removal rate of coarse magnetic powder is ≥99.9%, fine magnetic powder is ≥99.8%, and trace residual magnetic powder with a particle size ≤1μm has a removal rate ≥99.5%, completely solving the problem of iron ore magnetic powder mixed in the material. This enables the production of silicon coal while improving the desliming efficiency of the screen and reducing the load and media consumption of subsequent magnetic separation. The silicon coal centrifugal dewatering machine 23 adopts low-temperature centrifugal dewatering technology, with a cold water circulation cooling water temperature ≤25℃, avoiding coal particle oxidation and ensuring the chemical stability of the silicon coal product, with an oxidation rate ≤0.5%. The coking coal centrifuge 24 and the silicon coal centrifugal dewatering machine 23 are linked and controlled to coordinately adjust dewatering parameters, ensuring that the product moisture content is ≤8%.

[0111] The upper screen surface substrate is made of ceramic-metal composite material, which combines the wear resistance of ceramics with the toughness of metal, effectively resisting the erosion of materials. A nano-wear-resistant and anti-stick coating with added graphite-modified particles is sprayed onto the surface. These graphite-modified particles effectively prevent iron ore magnetic powder from adsorbing onto the screen surface, reducing magnetic powder residue.

[0112] The screen surface is internally embedded with multiple sets of high-gradient permanent magnet strips. These strips are arranged in a staggered, uniform pattern with a spacing of 30-50mm. The magnetic field direction is perpendicular to the material movement direction, forming a transverse magnetic field gradient. The magnetic field strength is 0.8-1.0T, and can be steplessly adjusted between 0.3-1.0T via a PLC control system. Based on the magnetic powder content in the material, the system automatically switches the magnetic intensity level. When the magnetic powder content is high, the magnetic intensity is increased to enhance the adsorption of the magnetic powder; when the magnetic powder content is low, the magnetic intensity is decreased to save energy.

[0113] The screen surface employs dual-frequency vibration excitation, with a vibration frequency of 50-60Hz and an amplitude adjustment range of 0.5-1.5mm. The vibration direction forms a 45° angle with the material movement direction. This vibration method enables both graded material conveying and the removal of large pieces of iron ore magnetic powder adhering to the material. Simultaneously, the vibration frequency is synchronized with the scraper speed to ensure that the adsorbed magnetic powder is promptly scraped off by the flexible, wear-resistant scraper to the upper collection trough. The flexible, wear-resistant scraper has a contact rate ≥99% with the screen surface, efficiently removing magnetic powder without damaging the screen surface.

[0114] The upper screen surface is equipped with a high-pressure desliming spray at 0.5-0.6 MPa, which can quickly wash away the large amount of heavy medium suspension adhering to the material surface, allowing most of the heavy medium to separate from the material in the early stage of screening. The upper screen surface is equipped with a medium-pressure rinsing spray at 0.3-0.4 MPa to remove residual magnetic powder in the material gaps, further improving the purity of the material.

[0115] The lower screen surface is divided into three sections: the front section desliming zone, the middle section deep magnetic separation zone, and the rear section rinsing and desorption zone, which are adjacent to each other in sequence.

[0116] The desizing zone of the front desizing screen adopts a fine and wear-resistant screen surface with a screen porosity of 35-40%. This porosity design improves the channel for removing fine magnetic powder particles, allowing fine magnetic powder particles to pass through the screen holes more effectively and achieve initial separation from the material.

[0117] A superconducting magnetic separation module is embedded in the mid-section deep magnetic separation zone, with a magnetic field strength of 1.5-2.0T and a magnetic field gradient of 10T / m³. The superconducting magnetic separation module consists of two layers: the upper layer has a magnetic field strength of 1.8-2.0T and is used to adsorb fine magnetic powder particles; the lower layer has a magnetic field strength of 1.5-1.8T and is used to adsorb trace amounts of residual magnetic powder. The magnetic field direction can be steplessly adjusted between 0-90° according to the material thickness. Simultaneously, an online magnetic flux detection module monitors changes in magnetic field strength in real time. When the magnetic flux fluctuation exceeds ±5%, magnetic field compensation is performed to ensure magnetic field stability and improve the magnetic separation effect.

[0118] The subsequent rinsing and desorption zone undergoes high-pressure spraying and ultrasonic vibration. The spraying pressure is 0.3-0.5 MPa, and the spraying water is magnetized circulating water with a magnetization intensity of 0.2T. This magnetized water has a stronger desorption capacity for magnetic powder. Simultaneously, a built-in 18kHz ultrasonic vibration device breaks the adsorption force between the magnetic powder and the coal particle surface through ultrasonic vibration, desorbing the residual trace magnetic powder. The desorbed fine magnetic powder particles fall into the lower collection tank.

[0119] In addition to the built-in ultrasonic vibration device on the lower screen surface, high-frequency ultrasonic generators are additionally installed on both sides of the screen body. The ultrasonic vibration is transmitted to the entire screen surface through the box, forming a combination of overall and localized ultrasonic effects. This not only breaks the adsorption force between magnetic powder and coal particles but also prevents magnetic powder from clogging the screen gaps. The ultrasonic frequency and the screen surface vibration frequency are linked and controlled, automatically adjusting the ultrasonic power and vibration frequency according to the magnetic powder content in the material, achieving synergistic optimization of desliming effect and energy saving.

[0120] A low-pressure magnetized spray is installed at the rear of the lower screen surface, with a pressure of 0.2-0.3 MPa. After being magnetized, the spray water specifically removes trace amounts of magnetic powder adsorbed on the surface of the material. The spray water adopts a closed-loop circulation system and is reused after magnetic separation filtration, reducing water consumption and preventing magnetic powder from being lost with the wastewater.

[0121] A magnetic separation and recovery module with a magnetic field strength of 1.2T is installed in the grading and collection tank at the bottom of the screen body to perform secondary magnetic separation and purification on the collected coarse and fine magnetic powder. The purified magnetic powder is returned to the qualified medium tank 31 for recycling via a conveying device, while the substandard magnetic powder is sent to the magnetic separation tailings treatment system. This design further improves the recovery rate of the medium and reduces the consumption of the medium.

[0122] The silicon coal centrifugal dewatering machine 23 adopts low-temperature centrifugal dewatering technology. It uses cold water circulation to cool the water temperature to ≤25℃, which avoids coal particle oxidation and ensures the chemical stability of silicon coal products. Its oxidation rate is ≤0.5%.

[0123] Furthermore, the coking coal centrifuge 24 and the silicon coal centrifugal dewatering machine 23 are linked and controlled to coordinately adjust the dewatering parameters, ensuring that the moisture content of both products is ≤8%. This linkage control method not only guarantees the stability of product quality but also improves the efficiency of the entire dewatering process.

[0124] The removal rate of iron ore magnetic powder by the double-layer screen 21 for desliming refined coal is more than 15% higher than that of conventional structures. The removal rate of coarse magnetic powder is ≥99.9%, the removal rate of fine magnetic powder is ≥99.8%, and the removal rate of trace residual magnetic powder with a particle size ≤1μm is ≥99.5%. This completely solves the problem of iron ore magnetic powder mixed in the material, providing a guarantee for the production of high-quality silicon coal products.

[0125] The screen design, spray system, and ultrasonic vibration technologies enable a highly efficient desliming process, improving production efficiency. Simultaneously, they reduce the load on subsequent magnetic separation, lowering energy consumption and wear on the magnetic separation equipment, and extending its service life.

[0126] The efficient magnetic powder removal and magnetic separation recovery modules improve the recovery rate of the medium, reduce the consumption of the medium, and save production costs.

[0127] The spray water adopts a closed-loop circulation system and is reused after magnetic separation filtration, which greatly reduces water consumption and avoids the loss of magnetic powder with wastewater, thus having good environmental benefits.

[0128] The low-temperature centrifugal dewatering technology of the silicon coal centrifugal dewatering machine 23 ensures the chemical stability of silicon coal products and reduces the impact of oxidation on the quality of silicon coal.

[0129] Furthermore, the linkage control of the coking coal centrifuge 24 and the silicon coal centrifugal dewatering machine 23 is selected to ensure that the moisture content of both products meets the standard, thus guaranteeing the consistency and stability of product quality.

[0130] This embodiment also proposes a sorting system for coal used in multi-product chemical processing, including a raw material pretreatment unit, a main sorting unit, a re-sorting unit, a medium gangue processing unit, a coal slime processing unit, and a media circulation unit. The connection relationship of each unit is as follows: The raw material pretreatment unit includes a desliming screen 1, a main sorting mixing tank 2, a main sorting mixing pump 3, and a main sorting qualified media tank 4; the discharge end of the desliming screen 1 is connected to the feed end of the main sorting mixing tank 2, and is used to send the 1-25mm material obtained after desliming into the main sorting mixing tank 2; the discharge end of the main sorting qualified media tank 4 is connected to the feed end of the main sorting mixing tank 2 through the main sorting mixing pump 5, and is used to feed the main sorting qualified media into the main sorting mixing tank 2; the discharge end of the main sorting mixing tank 2 is connected to the feed end of the main sorting unit through the main sorting mixing pump 3.

[0131] The main selection unit includes a main heavy medium three-product hydrocyclone 6, which has three discharge ends, respectively connected to the main gangue processing branch of the medium gangue processing unit, the main medium coal processing branch of the medium gangue processing unit, and the feed branch of the re-selection unit; the medium gangue processing unit includes the main gangue processing branch and the main medium coal processing branch.

[0132] The main gangue processing branch includes, in sequence, a main gangue arc screen 7, a main gangue desliming screen 10, and a main gangue magnetic separator 13; the gangue discharge end of the main heavy medium three-product hydrocyclone 6 is connected to the feed end of the main gangue arc screen 7, the undersize discharge end of the main gangue arc screen 7 is connected to the feed end of the main gangue desliming screen 10, and the dilute medium discharge end of the main gangue desliming screen 10 is connected to the feed end of the main gangue magnetic separator 13; the main gangue arc screen 7. The discharge end of the qualified medium under the screen of the main gangue desliming screen 10 is connected to the feed end of the qualified medium tank 4 for the circulation of qualified medium; the discharge end of the magnetic concentrate of the main gangue magnetic separator 13 is connected to the feed end of the qualified medium tank 4, and the discharge end of the magnetic tailings of the main gangue magnetic separator 13 is connected to the feed end of the fine gangue high-frequency screen 36 of the coal slime treatment unit; the discharge end of the gangue product of the main gangue desliming screen 10 is used to output gangue product.

[0133] The main medium coal processing branch includes, in sequence, a main medium coal arc screen 8, a main medium coal desliming screen 11, and a main medium coal centrifuge 15; the middlings discharge end of the main medium heavy medium three-product hydrocyclone 6 is connected to the feed end of the main medium coal arc screen 8, the undersize discharge end of the main medium coal arc screen 8 is connected to the feed end of the main medium coal desliming screen 11, and the discharge end of the main medium coal desliming screen 11 is connected to the feed end of the main medium coal centrifuge 15; the undersize qualified medium discharge ends of the main medium coal arc screen 8 and the main medium coal desliming screen 11 are both connected to the feed end of the main medium qualified medium tank 4 for qualified medium circulation; the dilute medium discharge end of the main medium coal desliming screen 11 is connected to the feed end of the main medium fine and medium magnetic separator 14; the dewatering discharge end of the main medium coal centrifuge 15 is used to output mixed coal products, and the centrifugal liquid discharge end of the main medium coal centrifuge 15 is connected to the feed end of the coal slime tank 27 of the coal slime treatment unit.

[0134] The reselection unit includes a main coal pretreatment branch, a reselection mixing tank 29, a reselection heavy medium three-product hydrocyclone 18, and a reselection product processing branch connected in sequence.

[0135] The main coal pretreatment branch includes, in sequence, a main coal arc screen 9, a main coal desliming screen 12, a main coal centrifuge 16, and a main coal quantitative feeder 17. The clean coal discharge end of the main heavy medium three-product hydrocyclone 6 is connected to the feed end of the main coal arc screen 9; the under-screen discharge end of the main coal arc screen 9 is connected to the feed end of the main coal desliming screen 12; the discharge end of the main coal desliming screen 12 is connected to the feed end of the main coal centrifuge 16; the discharge end of the main coal centrifuge 16 is connected to the feed end of the main coal quantitative feeder 17; and the discharge end of the main coal quantitative feeder 17 is connected to the feed of the re-selection mixing tank 29. The following connections are made: the discharge end of the qualified medium from the main coal arc screen 9 and the main coal desliming screen 12 is connected to the feed end of the main qualified medium tank 4 for qualified medium circulation; the discharge end of the dilute medium from the main coal desliming screen 12 and the discharge end of the diverting medium from the main coal arc screen 9 are connected to the feed end of the main coal fine and medium magnetic separator 14; the discharge end of the centrifugal liquid from the main coal fine centrifuge 16 is connected to the feed end of the coal slime tank 27 of the coal slime treatment unit; the discharge end of the magnetic concentrate from the main coal fine and medium magnetic separator 14 is connected to the feed end of the main qualified medium tank 4, and the discharge end of the magnetic tailings from the main coal fine and medium magnetic separator 14 is connected to the flushing end of the desliming screen 1.

[0136] The discharge end of the reselection mixing tank 29 is connected to the inlet end of the reselection heavy medium three-product cyclone separator 18 via the mixing pump 30; the reselection unit also includes a reselection qualified medium tank 31, the discharge end of which is connected to the inlet end of the reselection mixing tank 29 via the reselection mixing pump 32, for feeding the reselection medium into the reselection mixing tank 29.

[0137] The secondary product processing branch includes a silicon coal product processing branch and a secondary heavy product processing branch; the secondary heavy medium cyclone separator 18 has two discharge ends, which are respectively connected to the silicon coal product processing branch and the secondary heavy product processing branch.

[0138] The silicon coal product processing branch includes, in sequence, a re-selected clean coal arc screen 19, a re-selected clean coal desliming double-layer screen 21, and a silicon coal centrifugal dewatering machine 23; the ultra-low ash clean coal discharge end of the re-selected heavy medium three-product hydrocyclone 18 is connected to the feed end of the re-selected clean coal arc screen 19, the under-screen discharge end of the re-selected clean coal arc screen 19 is connected to the feed end of the re-selected clean coal desliming double-layer screen 21, the upper screen discharge end of the re-selected clean coal desliming double-layer screen 21 is connected to the feed end of the silicon coal centrifugal dewatering machine 23, and the discharge end of the silicon coal centrifugal dewatering machine 23 is used to output silicon coal products.

[0139] The heavy product processing branch sequentially includes a heavy product arc screen 20, a heavy product desliming screen 22, and a heavy product centrifuge 26. The heavy product discharge end of the heavy product hydrocyclone 18 is connected to the feed end of the heavy product arc screen 20, the undersize discharge end of the heavy product arc screen 20 is connected to the feed end of the heavy product desliming screen 22, the discharge end of the heavy product desliming screen 22 is connected to the feed end of the heavy product centrifuge 26, and the discharge end of the heavy product centrifuge 26... The bottom end is used to output the reselected heavy product; the undersize dilute medium discharge ends of the reselected clean coal desliming double-layer screen 21 and the reselected heavy product desliming screen 22 are both connected to the feed end of the reselected product magnetic separator 25, and the magnetic concentrate discharge end of the reselected product magnetic separator 25 is connected to the feed end of the reselected qualified medium tank 31 for reselected medium circulation; the lower screen discharge end of the reselected clean coal desliming double-layer screen 21 is connected to the feed end of the reselected coking coal centrifuge 24, and the discharge end of the reselected coking coal centrifuge 24 is used to output coking coal product; The coal slime treatment unit includes a coal slime bucket 27, a coal slime pump 28, a coal slime thickening and grading hydrocyclone group 33, a three-product interference bed separator 34, a fine-grained gangue high-frequency screen 36, a flotation machine 39, a thickener 44, and a coal slime recovery branch.

[0140] The feed end of the coal slime bucket 27 is connected to the 0-1mm material discharge end of the desliming screen 1, the centrifugal liquid discharge end of the main coal centrifuge 16, and the centrifugal liquid discharge end of the main coal centrifuge 15, respectively; the discharge end of the coal slime bucket 27 is connected to the feed end of the coal slime thickening and classifying hydrocyclone group 33 through the coal slime pump 28.

[0141] The coal slime thickening and classifying hydrocyclone group 33 has two discharge ends, which are respectively connected to the three-product interference bed separator 34 and the flotation machine 39. The discharge end of the coarse coal slime (1-0.25mm) of the coal slime thickening and classifying hydrocyclone group 33 is connected to the feed end of the three-product interference bed separator 34, and the discharge end of the fine coal slime (0-0.25mm) of the coal slime thickening and classifying hydrocyclone group 33 is connected to the feed end of the flotation machine 39.

[0142] The three-product interference bed separator 34 has three discharge ends, which are respectively connected to the fine coal slime grading and dewatering screen 35, the re-selection mixing tank 29, and the fine gangue high-frequency screen 36; the fine coal discharge end of the three-product interference bed separator 34 is connected to the feed end of the fine coal slime grading and dewatering screen 35, the middlings coal discharge end of the three-product interference bed separator 34 is connected to the feed end of the re-selection mixing tank 29, and the gangue discharge end of the three-product interference bed separator 34 is connected to the feed end of the fine gangue high-frequency screen 36; the fine coal slime grading and dewatering screen 35... The discharge end is connected to the feed end of the fine coal slime centrifuge 37. The discharge end of the fine coal slime centrifuge 37 is used to mix in coking coal products or 0-3mm ultra-low ash fine coal products. The under-screen water discharge end of the fine coal slime grading and dewatering screen 35 and the centrifugal liquid discharge end of the fine coal slime centrifuge 37 are both connected to the feed end of the coal slime bucket 27 through the centrifugal liquid transfer pump 38. The under-screen water discharge end of the fine gangue high-frequency screen 36 is connected to the feed end of the thickener 44. The discharge end of the fine gangue high-frequency screen 36 is used to feed in gangue products or mixed coal products.

[0143] Flotation machine 39 is a two-stage flotation machine, with its discharge end connected to thickener 44 and flotation concentrate tank 40 respectively. The discharge end of flotation concentrate tank 40 is connected to the feed end of flotation coal filter press 42 through flotation concentrate pump 41. The filter cake discharge end of flotation coal filter press 42 is used to output coking coal products or ultra-low ash coal products. The filtrate discharge end of flotation coal filter press 42 is connected to the feed end of thickener 44. The primary flotation tailings and secondary flotation tailings of flotation machine 39 are both connected to the feed end of thickener 44, and the secondary flotation tailings can be selectively returned to the feed end of flotation machine 39.

[0144] The coal slime recovery branch includes a thickener 44, a thickener underflow pump 45, a coal slime filter press 43, a circulating water tank 46, and a circulating water pump 47. The underflow discharge end of the thickener 44 is connected to the feed end of the coal slime filter press 43 through the thickener underflow pump 45. The filter cake discharge end of the coal slime filter press 43 is used to output coal slime products. The filtrate discharge end of the thickener 44 is connected to its own feed end, and the overflow discharge end of the thickener 44 is connected to the feed end of the circulating water tank 46. The discharge end of the circulating water tank 46 is connected to the inlet end of each water-requiring device in the system through the circulating water pump 47 for circulating water supply.

[0145] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention applied herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary technical means not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0146] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, but various modifications can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A process for the beneficiation of multi-product chemical coal, characterized in that, Includes the following steps: Main selection: The raw material is fed into the main selection heavy medium three-product hydrocyclone (6), and the main separation yields the main selected clean coal; Re-selection: The main selected clean coal is fed into the three-product hydrocyclone of the re-selection heavy medium (18) and then separated to obtain ultra-low ash clean coal. After the ultra-low ash clean coal is pre-de-mediumized, de-mediumized by de-mediumizing screen, and dewatered and classified, silicon coal product is obtained. Among them, the pre-de-mediumization of ultra-low ash clean coal is carried out in the re-selection clean coal arc screen (19), the de-mediumization by de-mediumizing screen is carried out in the re-selection clean coal de-medium double-layer screen (21), and the dewatering and classification is carried out in the silicon clean coal centrifugal dewatering machine (23). Wherein, the main sorting, sorting density 1.4-1.6 g / cm 3 , the re-sorting, sorting density 1.25-1.3 g / cm 3 .

2. A process for the beneficiation of coal for multi-product chemical use as claimed in claim 1 wherein, Before the main selected clean coal is fed into the three-product hydrocyclone (18) of the secondary heavy medium, the main selected clean coal first undergoes pre-demediation, demediation screen demediation, dewatering and classification and mixing treatment in sequence; Among them, the pre-demediation of the main refined coal is carried out in the main refined coal arc screen (9), the demediation of the main refined coal is carried out in the main refined coal demediation screen (12), the dewatering and classification of the main refined coal is carried out in the main refined coal centrifuge (16), and the mixing of the main refined coal is mixed with low-density heavy medium suspension in the re-selection mixing tank (29). After the main refined coal is dewatered and classified by the main refined coal centrifuge (16), it is transferred into the re-selection mixing tank (29) through the main refined coal quantitative feeder (17), and sent to the re-selection heavy medium three-product hydrocyclone (18) through the mixing pump (30).

3. The sorting process for coal used in multi-product chemical processing according to claim 2, characterized in that, The main heavy medium three-product hydrocyclone (6) also separates the main medium coal and the main gangue. The main medium coal is obtained by pre-demediation, demediation screen demediation and dewatering classification. The main gangue is obtained by pre-demediation, demediation screen demediation and dewatering classification. Among them, the pre-demediation of the main medium is carried out in the main medium arc screen (8), the demediation of the main medium is carried out in the main medium demediation screen (11), and the dewatering and classification of the main medium is carried out in the main medium centrifuge (15). The pre-demediation of the main gangue is carried out in the main gangue arc screen (7), and the demediation and dewatering of the main gangue are carried out in the main gangue demediation screen (10).

4. A process for the beneficiation of coal for multi-product chemical use as claimed in claim 3 wherein, Before the raw material is fed into the main heavy medium three-product hydrocyclone (6), it is first deslimed by the desliming screen (1) to obtain 1-25mm material. The 1-25mm material is fed into the main mixing tank (2) and then into the main heavy medium three-product hydrocyclone (6) by the main mixing pump (3). The main mixing tank (2) is also fed into the main qualified medium in the main qualified medium tank (4) by the main mixing pump (5). The qualified medium under the screens of the main coal arc screen (9), the main coal desliming screen (12), the main coal arc screen (8), the main coal desliming screen (11), the main gangue arc screen (7) and the main gangue desliming screen (10) are returned to the main qualified medium tank (4) for recycling. The dilute medium under the main coal desliming screen (12) and the main coal desliming screen (11) and part of the medium flowing out of the main coal arc screen (9) are sent to the main coal fine magnetic separator (14) for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the main qualified medium tank (4) for recycling. The tailings of the main coal fine magnetic separator (14) are used as flushing water for the desliming screen (1). The dilute medium under the screen of the main gangue desliming screen (10) is sent to the main gangue magnetic separator (13) for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is sent back to the main qualified medium tank (4) for recycling. The magnetic tailings of the main gangue magnetic separator (13) enter the magnetic tailings tank. After being concentrated by the hydrocyclone, the underflow is recovered by the high frequency screen and the overflow enters the thickener (44). The centrifugal liquid of the main fine coal centrifuge (16) and the centrifugal liquid of the main fine coal centrifuge (15) enter the coal slime tank (27).

5. A process for the beneficiation of coal for multi-product chemical use as claimed in claim 4 wherein, When the raw material is deslimed through the desliming screen (1), the 0-1mm material obtained from the desliming screen enters the coal slime bucket (27). The coal slurry in the coal slurry bucket (27) is pumped by the coal slurry pump (28) to the coal slurry thickening and classifying hydrocyclone group (33) for thickening and classification. The classification particle size is 0.25mm. The 1-0.25mm coarse coal slurry obtained from the classification is sent to the three-product interference bed separator (34) for classification. The clean coal separated by the three-product interference bed separator (34) is screened and dewatered by the clean coal slurry classification and dewatering screen (35) and the clean coal slurry centrifuge (37) and then mixed into coking coal products. Alternatively, the clean coal separated by the three-product interference bed separator (34) can be mixed with 0-3mm ultra-low ash coal. Coal products; the middlings separated by the three-product interference bed separator (34) are returned to the rewash mixing tank for rewashing. The gangue separated by the three-product interference bed separator (34) and the magnetic tailings of the main gangue magnetic separator (13) are dewatered by the fine gangue high frequency screen (36) and then enter the gangue products or mixed coal products. The screen water of the fine gangue high frequency screen (36) enters the thickener (44). The screen water of the fine coal slime grading dewatering screen (35) and the centrifugal liquid of the fine coal slime centrifuge (37) are sent to the coal slime bucket (27) through the centrifugal liquid transfer pump (38).

6. A process for the beneficiation of coal for multi-product chemical use as claimed in claim 5 wherein, When the coal slime thickening and grading hydrocyclone group (33) thickens and grades, the overflow fine coal slime 0-0.25mm material is treated by stirring and adding reagents by the slurry preprocessor and then fed into the flotation machine (39) for flotation separation. The flotation machine (39) is a two-stage flotation machine that performs two flotations. When only coking coal is produced, the high-ash tailings separated by the first flotation enter the thickener (44), the concentrate is sent to the flotation concentrate bucket (40) by the second flotation, and then sent to the flotation coal filter press (42) by the flotation concentrate pump (41). The flotation coal filter press (42) dewaters the coal as a coking coal product, and the filtrate from the flotation coal filter press (42) enters the thickener (44). The tailings from the second flotation enter the thickener (44) or are returned to the flotation machine (39) for further flotation. When producing ultra-low ash coal and coking coal at the same time, the tailings from the primary flotation enter the thickener (44), the concentrate from the secondary flotation is dewatered using the flotation coal filter press (42) and used as ultra-low ash coal product, the tailings from the secondary flotation are dewatered and used as coking coal product, and the secondary flotation coal is mixed with 0-3mm ultra-low ash coal product. The coal slurry water entering the thickener (44) is concentrated. The underflow of the thickener (44) is sent to the coal slurry filter press (43) through the thickener underflow pump (45). After being dewatered by the coal slurry filter press (43), the filter cake is used as the coal slurry product. The filtrate of the thickener (44) is returned to the thickener (44). The overflow of the thickener (44) is sent to the circulating water pool (46) for use as circulating water. The circulating water is pumped to the required location through the circulating water pump (47).

7. A process for the beneficiation of coal for multi-product chemical use as claimed in claim 1 wherein, The main selected clean coal is fed into the three-product hydrocyclone (18) for re-selection of heavy media. The re-selected heavy products are then obtained. The re-selected heavy products are pre-de-mediumized by the re-selection medium gangue arc screen (20), de-mediumized by the re-selected heavy product de-mediumized screen (22), and dewatered by the re-selected heavy product centrifuge (26) to obtain the re-selected heavy product product. The undersize medium from the double-layer screen (21) for desliming the refined coal and the screen (22) for desliming the heavy products is fed into the magnetic separator (25) for magnetic separation to obtain magnetic concentrate. The magnetic concentrate is returned to the qualified medium tank (31) for recycling. When ultra-low ash clean coal is de-saturated in the double-layer screen (21) of re-selected clean coal, the material on the upper screen is de-watered in the silicon clean coal centrifugal dewatering machine (23) to obtain silicon coal product, and the material on the lower screen is de-watered in the re-selected coking coal centrifugal machine (24) to obtain coking coal product. The qualified medium in the qualified medium tank (31) is sent into the qualified mixing tank (29) by the qualified medium pump (32).

8. A sorting process for coal used in multi-product chemical processing according to claim 7, characterized in that, The upper screen surface of the double-layer screen for desliming of refined coal (21) is made of ceramic-metal composite material, with a nano-wear-resistant and anti-stick coating sprayed on the surface. The nano-wear-resistant and anti-stick coating is modified with graphite particles to prevent the iron ore magnetic powder from adsorbing onto the screen surface. At the same time, multiple sets of high-gradient permanent magnet strips are embedded and integrated inside the screen surface. The magnetic field strength is 0.8-1.0T. The permanent magnet strips are arranged in a staggered and uniform manner with a spacing of 30-50mm. The magnetic field direction is perpendicular to the material movement direction, forming a transverse magnetic field gradient. The magnetic strength is infinitely adjustable from 0.3 to 1.0T through a PLC control system; the screen surface is excited by dual-frequency vibration, with a vibration frequency of 50-60Hz and an amplitude adjustable from 0.5 to 1.5mm. The vibration direction is at a 45° angle to the material movement direction. The magnetic adsorption of the built-in permanent magnet strips is used to adsorb and separate the coarse iron ore magnetic powder mixed on the surface and in the gaps of the material. The adsorbed magnetic powder is periodically scraped off to the upper collection tank by the built-in scraper device on the screen surface. The scraper device adopts a flexible wear-resistant scraper.

9. A sorting process for coal used in multi-product chemical processing according to claim 8, characterized in that, The lower screen surface of the double-layer screen (21) for desliming refined coal is divided into a front desliming zone, a middle deep magnetic separation zone, and a rear rinsing and desorption zone, which are adjacent to each other in sequence. Among them, the front desliming zone adopts a fine and wear-resistant screen surface with a screen porosity of 35%-40%. The middle deep magnetic separation zone is embedded with a superconducting magnetic separation module with a magnetic field strength of 1.5-2.0T and a magnetic field gradient of 10T / m³. The superconducting magnetic separation module is divided into upper and lower layers with a magnetic field strength of 1.8-2.0T in the upper layer and 1.5-1.8T in the lower layer. The field direction is infinitely adjustable from 0-90° according to the material thickness. The online magnetic flux detection module monitors the changes in magnetic field strength in real time, and performs magnetic field compensation when the magnetic flux fluctuation exceeds ±5%. The downstream rinsing and desorption zone is subjected to high-pressure spraying and ultrasonic vibration. The spraying pressure is 0.3-0.5MPa, and the spraying water is magnetized circulating water with a magnetization intensity of 0.2T. At the same time, a built-in 18kHz ultrasonic vibration device is used to destroy the adsorption force between the magnetic powder and the surface of the coal particles through ultrasonic vibration, desorbing the residual trace magnetic powder. The desorbed fine magnetic powder falls into the lower collection tank. The upper screen of the double-layer screen for desliming coal (21) is equipped with a high-pressure desliming spray at a pressure of 0.5-0.6 MPa to wash away the large amount of heavy medium suspension adhering to the surface of the material; the lower screen is equipped with a medium-pressure rinsing spray at a pressure of 0.3-0.4 MPa to remove the magnetic powder remaining in the gaps between the materials; the lower screen is equipped with a low-pressure magnetizing spray at a pressure of 0.2-0.3 MPa. After the spray water is magnetized, it removes the trace amount of magnetic powder adsorbed on the surface of the material. In addition to the built-in ultrasonic vibration device on the lower screen surface, high-frequency ultrasonic generators are additionally installed on both sides of the screen body box, and the ultrasonic vibration is transmitted to the entire screen surface through the box. A magnetic separation and recovery module is set in the grading and collection tank at the bottom of the screen body. The magnetic field strength is 1.2T. The collected coarse and fine magnetic powder is purified by secondary magnetic separation. The purified magnetic powder is returned to the qualified medium tank (31) for recycling through the conveying device. The unqualified magnetic powder is sent to the magnetic separation tailings treatment system.

10. A coal preparation system for multi-product chemical coal, characterized by, It includes a primary heavy medium three-product cyclone separator (6) and a secondary heavy medium three-product cyclone separator (18) connected in sequence.

Images