Carbon residue separation device for coal gasification ash recovery

Abstract

The invention discloses a carbon residue separation device for coal gasification ash recovery, and relates to the technical field of ash recovery carbon residue, the carbon residue separation device specifically comprises an airflow separation tank and a crushing hopper, the crushing hopper is fixed to the side wall of the airflow separation tank through welding, and a graded crushing mechanism is installed on the airflow separation tank; according to the invention, airflow separation optimization is carried out, low-density carbon residues and high-density ash residues are effectively separated by utilizing ascending airflow and density difference generated by a fan impeller, the capture rate of fine particles is improved, meanwhile, the fine particles are assisted to move between a grinding sleeve and a separation sleeve, and a ventilation pipe on the side of a circulating cover actively feeds air to drive crushed dust to move, so that the dust removal efficiency is improved. And meanwhile, through rotation of the crushing barrel, the crushing balls at the ends of the L-shaped rods can rotate and make contact with ash residues to complete crushing work, vibration is generated at the same time, the outer wall of the filter screen barrel for intercepting the ash residues is automatically brushed, and the screening efficiency of the fine ash residues and carbon residue dust is improved.

Description

Technical Field

[0001] The invention relates to the technical field of recovering carbon residue from ash, and in particular to a device for separating carbon residue from coal gasification ash. Background Art

[0002] During the coal gasification process, the incompletely burned carbon (residual carbon) remaining in the ash needs to be recovered through efficient separation technology to improve resource utilization and reduce environmental impact. It is usually divided into material, chemical and thermal treatment and combined treatment methods. For the treatment method, the coal gasification ash needs to be crushed in the early stage to obtain the corresponding air flow separation, heavy medium separation and water medium separation particle size.

[0003] Gravity separation of coal gasification ash is a physical separation technology based on the density difference between carbon residue and ash residue. It has the advantages of mature technology, low cost, and easy scalability. The carbon residue has a low density and the ash has a high density. Separation is achieved through the difference in sedimentation velocity in the medium (air, water or heavy liquid).

[0004] Gravity separation is also divided into dry separation and wet separation. In actual application, the dry or wet process should be selected based on the ash characteristics, processing scale and environmental protection requirements. If necessary, flotation, screening and other technologies can be combined to further improve the recovery rate.

[0005] When obtaining residual carbon, for example, the invention patent with publication number CN114798149B, "Method for sorting residual carbon from carbon-containing coal ash and airflow sorting system", uses a cyclone separator to sort large and small carbon-containing ash particles, and then uses a pulse bag dust collector to obtain carbon-rich slag. However, the cyclone separator is cost-effective in low humidity and coarse particle (0.1-3mm) scenarios. Fine particles have small inertia and are difficult to be effectively captured by centrifugal force, and easily escape to the exhaust port with the airflow. At the same time, the high-speed airflow continuously impacts the inner wall due to the angle problem, causing severe wear and tear on the inner wall, requiring frequent replacement of the wear-resistant lining (such as ceramic coating). For this reason, the following solution is proposed. Summary of the Invention

[0006] The object of the present invention is to provide a device for separating residual carbon for recovering coal gasification ash to solve the problems raised in the above background technology.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solution: a device for separating residual carbon for recovering coal gasification ash, comprising an airflow separation tank and a crushing bucket, wherein the crushing bucket is fixed to the side wall of the airflow separation tank by welding, a grading crushing mechanism is installed on the airflow separation tank, a grinding sleeve is fixedly connected to the bottom of the partition in the airflow separation tank, a separation sleeve is fixedly connected to the inner wall of the airflow separation tank and located on the side of the grinding sleeve, the grinding sleeve is connected to the separation sleeve, and a dust exhaust pipe is connected to the side wall of the airflow separation tank;

[0008] The grading and crushing mechanism includes a drive shaft, a fan impeller and a crushing barrel. The output end of the motor at the top of the airflow sorting tank is fixedly connected to the drive shaft, and one end of the drive shaft is movably connected to the inner wall of the bottom of the airflow sorting tank through a bearing. The outer wall of the drive shaft is sleeved and fixed with a fan impeller located on the top of the partition. The drive shaft is located on the outer wall of the bottom of the partition and is sleeved and fixed with a crushing barrel. The outer wall of the crushing barrel is evenly and movably connected with a grinding ring.

[0009] Furthermore, the grinding ring and the inner wall groove of the grinding sleeve are arranged correspondingly, and the distance between adjacent grinding rings and the grinding sleeve grooves differs by 0.3-0.5 mm.

[0010] Furthermore, crushing rollers are symmetrically installed on the inner walls of both sides of the crushing bucket, and the through pipes at the bottom of the crushing bucket respectively penetrate the air flow separation tank, the separation sleeve and the grinding sleeve and extend to the top of the crushing cylinder.

[0011] Furthermore, a filter screen is fixed to the bottom of the inner wall partition of the air flow separation tank by bolts, a scraper sleeve is slidably connected to the outer wall of the filter screen, a mesh brush is evenly fixed to the inner wall of the scraper sleeve, and the mesh brush is in contact with the inner wall of the filter screen.

[0012] Furthermore, an L-shaped rod is rotatably connected to the fixed bracket at the top of the crushing cylinder, a crushing ball is fixed to the end of the L-shaped rod by welding, and the other end of the L-shaped rod is in contact with the bottom of the scraper sleeve.

[0013] Furthermore, a circulation cover is fixedly connected to the bottom of the outer wall of the air flow separation tank, a ventilation pipe is fixed to the side wall of the circulation cover, an isolation sleeve is slidably connected inside the circulation cover and located on the outer wall of the air flow separation tank, and arc filter plates are evenly installed on the side walls of the isolation sleeve.

[0014] The method of separating the residual carbon from the coal gasification ash recovery device is as follows:

[0015] Multi-stage crushing, carbon-containing ash is discharged from the top of the crushing bucket, crushed by the crushing roller and automatically flows into the top of the crushing cylinder in the grinding sleeve. The driving shaft rotates at high speed to realize the rotation of the crushing cylinder and the L-shaped rod. The initially crushed ash falls along the gap between the crushing cylinder and the grinding sleeve, and contacts the grinding ring in the rolling process, squeezed and crushed, and finally discharged through the gap between the grinding sleeve and the separation sleeve.

[0016] In the blast type separation, ventilation is carried out through the vent pipe, and the air flow contacts the crushed ash. The mixed slag particles are constantly moving in the circulation cover. At the same time, the drive shaft drives the fan impeller to rotate, causing some of the crushed mixed slag with a particle size of 0.1-3mm to move upward along the separation sleeve, and finally contact the filter cylinder and come to the top side of the air flow separation tank and be discharged through the dust exhaust pipe. As the crushing bucket continues to feed, the falling ash contacts the high-speed rotating L-shaped rod, causing the centrifugal forming angle of the L-shaped rod to decrease, causing the scraper sleeve abutting the L-shaped rod to continuously slide on the surface of the filter cylinder. The inner mesh brush continuously cleans the unscreened large particles of ash and automatically falls into the crushing cylinder for re-crushing. The mixed particles discharged through the dust exhaust pipe are mixed with water to form a slurry with a concentration controlled at 25-35% solid content. Lime or sulfuric acid is added to adjust the slurry pH to 6-9, and reagents are added to start flotation.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention adopts high-efficiency multi-stage crushing and sorting. Through the layer-by-layer grinding of the crushing roller and the crushing drum, the ash is finely crushed, ensuring uniform particle size and improving the efficiency of subsequent sorting. At the same time, the rotation of the crushing drum can also realize the rotation of the crushing ball at the end of the L-shaped rod, which contacts the ash to complete the crushing work and generates vibration, indirectly driving the scraper sleeve on the filter cylinder to move, automatically scrubbing the outer wall of the filter cylinder that intercepts the powder slag, and improving the screening efficiency of fine ash and residual carbon dust;

[0019] 2. In the present invention, airflow sorting is optimized, and the rising airflow and density difference generated by the fan impeller are used to effectively separate low-density carbon residue and high-density ash, thereby improving the capture rate of fine particles. At the same time, the fine particles are assisted to move between the grinding sleeve and the separation sleeve. The ventilation pipe on the side of the circulation cover actively intakes air, which drives the crushed dust to move, making it easier for the rising airflow generated by the fan impeller to capture fine dust, thereby improving the subsequent fine particle ash filtration efficiency;

[0020] 3. In the present invention, a combined flotation purification process is adopted to further separate the obtained fine ash and residual carbon dust. By adjusting the pH of the ore pulp and adding reagents, the residual carbon is further purified in combination with the flotation process to improve the recovery rate and product purity. Through the synergistic effect of mechanical crushing, air flow separation and flotation process, the problems of fine particle escape, equipment wear and low sorting efficiency in traditional methods are solved, and the residual carbon recovery rate and resource utilization rate are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of the carbon residue separation device for recovering coal gasification ash of the present invention;

[0022] Figure 2 This is a schematic cross-sectional view of a carbon residue separation device for recovering coal gasification ash according to the present invention;

[0023] Figure 3 This is a schematic diagram of the main structure of the carbon residue separation device for recovering coal gasification ash of the present invention;

[0024] Figure 4 It is a rear cross-sectional schematic diagram of a carbon residue separation device for recovering coal gasification ash of the present invention;

[0025] Figure 5 This is a schematic diagram of the installation structure of the isolation sleeve of the present invention;

[0026] Figure 6 This is a schematic diagram of the L-shaped rod rotating and lifting scraper sleeve structure of the present invention.

[0027] In the figure: 1. Air flow separation tank; 2. Crushing bucket; 3. Crushing roller; 4. Dust exhaust pipe; 5. Grading crushing mechanism; 501. Drive shaft; 502. Fan impeller; 503. Crushing cylinder; 504. Grinding ring; 6. Filter cylinder; 7. Scraper sleeve; 8. L-shaped rod; 9. Crushing ball; 10. Grinding sleeve; 11. Separation sleeve; 12. Circulation cover; 13. Isolation sleeve; 14. Curved filter plate; 15. Ventilation pipe; 16. Mesh brush. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1-6 , the present invention provides a technical solution:

[0030] Example 1: Considering that the ash particle size produced by traditional crushing varies greatly, the separation efficiency of fine particles is low when separating the coal gasification ash and carbon residue, which affects the flotation operation of the coal gasification ash and carbon residue in the subsequent combined treatment;

[0031] For this purpose, the crushing drum 503 is installed on the basis of the original crushing roller 3 crushing, such as Figure 1 and Figure 2 As shown, a crushing bucket 2 is installed on the airflow separation tank 1, and the primary ash crushed by the crushing roller 3 in the crushing bucket 2 falls directly into the airflow separation tank 1 for secondary fine crushing treatment;

[0032] The motor at the top of the airflow separation tank 1 is equipped with a grading crushing mechanism 5. The drive shaft 501 on the output end of the motor drives the crushing cylinder 503 in the airflow separation tank 1 to rotate, and a grinding sleeve 10 is installed in the airflow separation tank 1 to match it. Figure 2As shown, the grinding rings 504 are evenly installed on the outer wall of the crushing cylinder 503. As the crushing cylinder 503 rotates at high speed, the grinding rings 504 on the surface rotate in the grooves on the inner wall of the grinding sleeve 10 to squeeze and crush the crushed materials in the falling process.

[0033] For the installation of grinding ring 504, the outer wall of crushing cylinder 503 is divided into five layers from top to bottom, and the spacing between the grinding ring 504 and the grinding sleeve 10 of adjacent layers differs by 0.4mm, that is, the ash crushing particle size becomes smaller as you go to the bottom layer. At the same time, the grinding ring 504 on the crushing cylinder 503 of adjacent layers is staggered to achieve full coverage of the crushing angle and avoid the increase of the probability of slag leakage.

[0034] The crushing cylinder 503 rotates and grinds, and the fine mixed particles come to the bottom of the grinding sleeve 10, and then pass through the hole between the separation sleeve 11 to the side wall of the circulation cover 12. The low-density carbon residue particles are obtained by air flow sorting. Considering the carbon residue density of 1.2-1.8g / cm 3 The density of ash is 2.5-3.0g / cm 3 The difference is large. As the driving shaft 501 rotates, the fan impeller 502 rotates and continuously generates an upward airflow, and the fine mixed particles begin to move upward along the separation sleeve 11.

[0035] The air flow separation tank 1 is divided into areas by setting partitions, such as Figure 4 As shown, the ash is crushed at the bottom of the partition, and the fine ash dust is collected at the top of the partition by the rotating fan impeller 502. To avoid large differences in the particle size of the fine ash dust, a filter cylinder 6 is installed at the bottom of the partition. The dust-laden air flow is intercepted by the filter cylinder 6 upward, and mixed particles with a particle size of 0.01-0.5mm pass directly through, while particles larger than 0.5mm are directly intercepted outside. The continuously discharged mixed particles are connected to the flotation equipment through the dust exhaust pipe 4 located on the side of the airflow separation tank 1.

[0036] The surface of the carbon residue is highly hydrophobic, while the surface of the ash is highly hydrophilic. The separation is achieved by selective adsorption of hydrophobic particles by bubbles. The ash is mixed with water in the flotation equipment to form a slurry with a concentration controlled at 30% solid content. Lime or sulfuric acid is added to adjust the slurry pH to 7.5. Collectors and bubbling agents are then added to the mixed slurry, and the flotation operation is carried out after stirring.

[0037] Finally, the foam containing residual carbon is collected by a scraper, and the residual carbon product is obtained after dehydration and drying. According to the density difference between the ash and the residual carbon, air flow separation is first performed, and the crushing roller 3 and the grinding ring 504 on the crushing cylinder 503 are used to refine and crush the ash and residual carbon layer by layer to obtain ash and residual carbon particles with uniform texture. Then, the ash and residual carbon particles are effectively filtered and intercepted by the filter cylinder 6, which is conducive to the subsequent flotation operation of fine particles and improves the residual carbon recovery rate.

[0038] Example 2: Considering the problem that some large particles of powder residue are blocked on the surface of the filter cylinder 6 during the air flow sorting process, affecting the subsequent screening of powder residue with normal particle size, Figure 4 As shown, a scraping sleeve 7 is installed on the outer wall of the entire filter cylinder 6, and a mesh brush 16 is installed on the inner wall of the scraping sleeve 7. By driving the scraping sleeve 7 to move, the dust on the outer wall of the filter cylinder 6 is scrubbed, and then the fallen dust returns to the top of the crushing cylinder 503, starting a new round of crushing work;

[0039] To achieve the vertical movement of the scraper sleeve 7, multiple sets of L-shaped rods 8 are installed on the top of the crushing cylinder 503. Figure 6 As shown, a crushing ball 9 is fixed to the end of the L-shaped rod 8. As the driving shaft 501 drives the crushing cylinder 503 to rotate, the centrifugal force generated on the crushing cylinder 503 causes the L-shaped rod 8 with the crushing ball 9 to expand;

[0040] Under normal conditions, the scraper sleeve 7 hangs down due to its own gravity and abuts against the side wall of the L-shaped rod 8. When the entire L-shaped rod 8 rotates and expands, the upper side of the rotation center of the L-shaped rod 8 rotates diagonally upward, thereby pushing the entire scraper sleeve 7 upward. If the crushing cylinder 503 keeps rotating at a constant speed at this time and the entire L-shaped rod 8 is not affected by the outside world, the entire scraper sleeve 7 remains stationary on the outer wall of the filter cylinder 6.

[0041] When the bottom pipe of the entire crushing bucket 2 extends to the top of the crushing cylinder 503 and is located on the side of the crushing ball 9, the initially crushed ash that falls continuously contacts the L-shaped rod 8, hitting the crushing ball 9 and crushing itself. The L-shaped rod 8 is squeezed and the deflection angle changes, causing the scraper sleeve 7 on the other side to start vibrating. The mesh brush 16 inside the scraper sleeve 7 starts to scrub and clean the inner wall of the filter cylinder 6, ensuring that the outer wall of the entire filter cylinder 6 is not affected by large particles of ash.

[0042] In order to improve the efficiency of the movement of the ash dust in the separation sleeve 11, a circulation cover 12 is installed on the entire air flow separation tank 1, and an isolation sleeve is installed in the circulation cover 12. Figure 5 As shown, the outer wall of the isolation cover is evenly installed with arc-shaped filter plates 14. At the same time, the isolation cover can move on the outer wall of the airflow separation tank 1. When airflow separation is carried out, the vent pipe 15 on one side of the circulation cover 12 is inflated, and the air flow contacts the side of the separation sleeve 11 along the circulation cover 12 and the isolation sleeve 13 to crush the ash and blow the ash particles into motion.

[0043] Since the through holes of the grinding sleeve 10 and the separation sleeve 11 are obliquely cut downward, the airflow blows the entire ash particles to circulate between the separation sleeve 11 and the grinding sleeve 10, and as the fan impeller 502 rotates, an upward suction force is generated, which improves the sorting efficiency of the crushed ash particles. At the same time, some large particle residues that have not risen with the airflow need to be crushed again. For this purpose, the entire isolation sleeve 13 can be pulled up, separated from the circulation cover 12 and exposed to the outer wall of the airflow separation tank 1, and the remaining residue is cleaned.

[0044] Working Principle: After being initially crushed by the crushing roller 3 of the crushing bucket 2, the carbon-containing ash falls into the top of the crushing drum 503 in the airflow separation tank 1. The driving shaft 501 drives the crushing drum 503 to rotate at high speed. The gap between the grinding ring 504 and the grinding sleeve 10 squeezes the ash layer by layer to achieve secondary fine crushing. The airflow introduced by the ventilation pipe 15, combined with the rising airflow of the fan impeller 502, causes the fine particles of carbon residue to float along the separation sleeve 11 to the filter cylinder 6, and the ash particles with higher density sink to the bottom of the grinding sleeve 10, completing the initial separation.

[0045] The L-shaped rod 8 of the crushing cylinder 503 pushes the scraper sleeve 7 to vibrate under the action of centrifugal force, and the mesh brush 16 automatically cleans the surface of the filter cylinder 6. The intercepted large particles of ash fall back into the crushing cylinder 503 and are crushed again. The mixed particles after sorting form a slurry with water. Through pH adjustment and the addition of reagents, the flotation process is used to selectively adsorb the residual carbon, and finally a high-purity residual carbon product is obtained.

[0046] The above contents are merely examples and explanations of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0047] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0048] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A device for separating residual carbon from coal gasification ash, comprising an airflow separation tank (1) and a crushing bucket (2), wherein the crushing bucket (2) is fixed to the side wall of the airflow separation tank (1) by welding, and characterized in that: The airflow separation tank (1) is provided with a grading crushing mechanism (5), a grinding sleeve (10) is fixedly connected to the bottom of the partition in the airflow separation tank (1), a separation sleeve (11) is fixedly connected to the inner wall of the airflow separation tank (1) and located on the side of the grinding sleeve (10), the grinding sleeve (10) is connected to the separation sleeve, and a dust exhaust pipe (4) is connected to the side wall of the airflow separation tank (1); The grading and crushing mechanism (5) comprises a driving shaft (501), a fan impeller (502) and a crushing cylinder (503); the output end of the motor at the top of the airflow separation tank (1) is fixedly connected to the driving shaft (501), and one end of the driving shaft (501) is movably connected to the inner wall of the bottom of the airflow separation tank (1) through a bearing; the fan impeller (502) is fixedly sleeved on the outer wall of the driving shaft (501) and located at the top of the partition; the crushing cylinder (503) is fixedly sleeved on the outer wall of the driving shaft (501) located at the bottom of the partition; and the outer wall of the crushing cylinder (503) is evenly and movably connected to a grinding ring (504).

2. The device for separating residual carbon from coal gasification ash according to claim 1, characterized in that: The grinding ring (504) is arranged corresponding to the inner wall groove of the grinding sleeve (10), and the spacing between the grooves of adjacent grinding rings (504) and grinding sleeve (10) differs by 0.3-0.5 mm.

3. The device for separating residual carbon from coal gasification ash according to claim 2, characterized in that: Crushing rollers (3) are symmetrically mounted on the inner walls of both sides of the crushing bucket (2). The bottom pipe of the crushing bucket (2) respectively penetrates the airflow separation tank (1), the separation sleeve (11) and the grinding sleeve (10) and extends to the top of the crushing cylinder (503).

4. The device for separating residual carbon from coal gasification ash according to claim 3, characterized in that: A filter screen cylinder (6) is fixed to the bottom of the inner wall partition of the air flow separation tank (1) by bolts, a scraper sleeve (7) is sleeved on the outer wall of the filter screen cylinder (6) and is slidably connected thereto, a mesh brush (16) is evenly fixed on the inner wall of the scraper sleeve (7), and the mesh brush (16) abuts against the inner wall of the filter screen cylinder (6).

5. The device for separating residual carbon from coal gasification ash according to claim 4, characterized in that: An L-shaped rod (8) is rotatably connected to the fixed bracket at the top of the crushing cylinder (503), a crushing ball (9) is fixed to the end of the L-shaped rod (8) by welding, and the other end of the L-shaped rod (8) is in contact with the bottom of the scraper sleeve (7).

6. The device for separating residual carbon from coal gasification ash according to claim 5, characterized in that: A circulation cover (12) is fixedly connected to the bottom of the outer wall of the air flow separation tank (1), a ventilation pipe (15) is fixedly connected to the side wall of the circulation cover (12), an isolation sleeve (13) is slidably connected to the outer wall of the air flow separation tank (1) and is sleeved inside the circulation cover (12), and arc filter plates (14) are evenly installed on the side walls of the isolation sleeve (13).

7. The device for separating residual carbon from coal gasification ash recovery according to claim 6, characterized in that: The method of separating the residual carbon device for recovering the coal gasification ash is as follows: Multi-stage crushing: ash containing carbon is discharged from the top of the crushing bucket (2), crushed by the crushing roller (3), and then automatically flows into the top of the crushing cylinder (503) in the grinding sleeve (10). The driving shaft (501) rotates at high speed to realize the rotation of the crushing cylinder (503) and the L-shaped rod (8). The initially crushed ash falls along the gap between the crushing cylinder (503) and the grinding sleeve (10), and contacts the grinding ring (504) in the rolling process, is squeezed and crushed, and finally discharged along the gap hole between the grinding sleeve (10) and the separation sleeve (11); In the blast type separation, the ventilation pipe (15) is ventilated, and the air flow contacts the crushed ash, and the particle mixed slag continuously moves in the circulation cover (12). At the same time, the drive shaft (501) drives the fan impeller (502) to rotate, causing part of the crushed mixed slag with a particle size of 0.1-3 mm to move upward along the separation sleeve (11), and finally contact the filter cylinder (6) and come to the top side of the air flow separation tank (1), and be discharged through the dust exhaust pipe (4). As the crushing bucket (2) continues to feed, the falling ash contacts the high-speed rotating L-shaped rod. (8), causing the centrifugal forming angle of the L-shaped rod (8) to decrease, causing the scraper sleeve (7) abutting the L-shaped rod (8) to continuously slide on the surface of the filter screen cylinder (6), and continuously cleaning the large particles of ash that have not been screened through the inner screen brush (16), and automatically falling into the crushing cylinder (503) for re-crushing, and the mixed particles discharged through the dust discharge pipe (4) are mixed with water to form a slurry, the concentration of which is controlled at 25-35% solid content, and lime or sulfuric acid is added to adjust the slurry pH to 6-9, and reagents are added to start flotation work.

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