Anti-ring formation mechanism for metallurgical rotary kiln

Abstract

The application discloses a kind of anti-ring mechanism of metallurgical rotary kiln, belong to metallurgical machinery technical field.It includes lower bolster plate, and upper bolster plate is set on lower bolster plate by lifting device, and bolster wheel bearing seat is set on upper bolster plate by front and back side, and bolster wheel is placed on bolster wheel, and inner ring is coaxially set in outer ring by connecting rod in outer ring, and inner ring is located inside rotary kiln cylinder, and outer ring is located outside rotary kiln cylinder, and connecting rod is movably passed through strip-shaped through hole corresponding to be opened in rotary kiln cylinder.The application can reduce the ring accident caused by instrument in kiln or worker's mistake, and can set timing to use the mechanism to clean kiln skin in automatic program;The application is more environmentally friendly and energy-saving, can better protect the loss of kiln skin refractory material caused by ring, reduce the pollution and waste caused by better refractory material.

Description

Technical Field

[0001] This invention relates to the field of metallurgical machinery technology, specifically to an anti-ringing mechanism for a metallurgical rotary kiln. Background Technology

[0002] During the smelting of laterite nickel ore, due to its high moisture content, it is generally dried at 100-300℃ before further smelting.

[0003] Before smelting, raw materials are often prepared. For example, in rotary kiln electric furnace (RKEF) smelting, pre-reduction roasting is required. The temperature inside the roasting kiln reaches up to 1300℃ at its highest point. In the high-temperature zone, the material often reaches a semi-molten state. This semi-molten material moves within the rotary kiln and begins to agglomerate after leaving the high-temperature section of the burner flame, forming rings. These rings easily adhere to the inner wall of the rotary kiln. If not cleaned in time, they tend to accumulate, causing blockages and potentially leading to major production accidents.

[0004] When laterite nickel ore is smelted in a rotary kiln for sulfidation and then transferred to a side-blown furnace or flash furnace for smelting, the high temperature often leads to the formation of ring-shaped materials, which can easily clog the rotary kiln. In the direct reduction process of laterite nickel ore, where the temperature inside the kiln can reach up to 1500℃, accidents caused by this ring-shaped material formation are particularly prominent.

[0005] The problem of ring formation in rotary kilns is currently addressed in the industry primarily by controlling raw materials and temperature. This includes controlling the ash content and calorific value of the bituminous coal used in the burner, and employing expensive, high-quality fuels. Simultaneously, the iron and aluminum content in the laterite nickel ore blend is carefully controlled. These stringent requirements for raw materials have led to the increasing scarcity and cost of such high-quality coal and laterite nickel ore. Furthermore, the automation and manual control of rotary kilns are subject to extremely demanding requirements.

[0006] In this situation, we have to find ways to solve the ring formation problem by addressing issues other than raw materials and control, in order to reduce the smelting cost of laterite nickel ore and tap its resource potential. Summary of the Invention

[0007] The purpose of this invention is to provide an anti-ringing mechanism for a metallurgical rotary kiln, solving the ringing phenomenon commonly found in the laterite nickel ore smelting process. This reduces the requirements for raw materials and control in these processes, thereby lowering smelting costs and conserving resources. This addresses the problems mentioned in the background section.

[0008] The technical solution adopted in this invention is as follows:

[0009] An anti-ringing mechanism for a metallurgical rotary kiln includes a lower support plate 1. An upper support plate 2 is provided above the lower support plate 1 via a lifting device 10. Support rollers 4 are provided on the front and rear sides of the upper support plate 2 via support roller bearing seats 3. An outer ring 5 is placed on the support roller 4. An inner ring 7 is coaxially provided inside the outer ring 5 via a connecting rod 6. The inner ring 7 is located inside the rotary kiln cylinder 9, and the outer ring 5 is located outside the rotary kiln cylinder 9. The connecting rod 6 moves through a corresponding strip-shaped through hole on the rotary kiln cylinder 9.

[0010] The lower support plate 1 is provided with a guide rod 8, which moves through the corresponding through hole on the upper support plate 2.

[0011] The lifting device 10 is a hydraulic cylinder, and there are four of them, which are distributed at the four corners of the lower support plate 1.

[0012] The lifting device 10 is a worm gear jack.

[0013] A dust cover is installed at the opening on the outer wall of the rotary kiln cylinder 9 on the connecting rod 6.

[0014] Two rows of connecting rods 6 are arranged radially between the outer ring 5 and the inner ring 7, with multiple connecting rods 6 evenly distributed along the circumferential direction in each row.

[0015] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0016] 1. In the smelting of laterite nickel ore, some raw materials currently considered prone to ring formation can be used. For example, the current requirement for rotary kiln pulverized coal injection is that it must use bituminous coal with an ash content of less than 10%. Using this invention, the ash content requirement for bituminous coal can be increased to less than 15%. This high-ash bituminous coal has a better cost-performance ratio and is conducive to reducing costs. For example, the current requirement is that the iron content of the laterite nickel ore feed material should not exceed 20%. After using this invention, the iron content of the laterite nickel ore feed material can also be appropriately increased. The range of raw material adaptability is wider, the resource requirements are reduced, and the resource potential is tapped.

[0017] 2. This invention can reduce ring formation accidents caused by instrument or worker errors in the kiln, and the mechanism can be set to clean the kiln lining at regular intervals in the automation program;

[0018] 3. Using this invention is more environmentally friendly and energy-saving, and can better protect the kiln skin refractory material loss caused by ring formation, reducing pollution and waste caused by better refractory materials. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the installation of the present invention;

[0021] Figure 3 for Figure 2 Sectional view at point A;

[0022] Figure 4 This is a schematic diagram of the structure when the centers of the outer and inner rings of the present invention are eccentric to the center of the rotary kiln.

[0023] The following are shown in the figure: lower support plate 1; upper support plate 2; support roller bearing seat 3; support roller 4; outer ring 5; connecting rod 6; inner ring 7; guide rod 8; rotary kiln body 9; lifting device 10; ring-forming material 11; burner 12; kiln head cover 13. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] like Figure 1-4 This embodiment provides an anti-ringing mechanism for a metallurgical rotary kiln, including a lower support plate 1. An upper support plate 2 is provided above the lower support plate 1 via a lifting device 10. Support rollers 4 are provided on the front and rear sides of the upper support plate 2 via support roller bearing seats 3. An outer ring 5 is placed on the support roller 4. An inner ring 7 is coaxially provided inside the outer ring 5 via a connecting rod 6. The connecting rod 6 is evenly distributed between the outer ring 5 and the inner ring 7 along the circumferential direction. The inner ring 7 is located inside the rotary kiln shell 9, and the outer ring 5 is located outside the rotary kiln shell 9. The connecting rod 6 moves through a corresponding strip-shaped through hole opened on the rotary kiln shell 9.

[0027] The lower support plate 1 is provided with a guide rod 8, which moves through the corresponding through hole on the upper support plate 2.

[0028] The lifting device 10 can be a hydraulic cylinder, and there are four of them, distributed at the four corners of the lower support plate 1.

[0029] The lifting device 10 can also be a worm gear lift.

[0030] A dust cover is installed at the opening on the outer wall of the rotary kiln cylinder 9 on the connecting rod 6 to prevent dust from being emitted because the hole diameter is larger than the connecting rod diameter.

[0031] Two rows of connecting rods 6 are arranged radially between the outer ring 5 and the inner ring 7, with 6-30 connecting rods 6 evenly distributed along the circumferential direction in each row.

[0032] In this invention, the inner ring and connecting rod are made of high-temperature resistant alloy, and the outer ring is made of alloy steel; the outer wall of the inner ring can be one of the following structures: smooth wall, toothed, toothed, floating point, inverted V-shaped, or plowshare-shaped.

[0033] The method of using the anti-ringing mechanism of the metallurgical rotary kiln is as follows: First, through holes are made along the circumferential direction at the ash landing point of the burner in the rotary kiln. The number of holes is 6-30, and the hole shape is strip-shaped. The strip-shaped holes allow the connecting rod to move vertically relative to the through holes. Then, the connecting rod is inserted into the through holes, and the inner and outer rings are fixed at both ends of the connecting rod, ensuring that the centers of the inner and outer rings are on the same circle. Then, a dust cover is installed at the opening of the outer ring of the rotary kiln to prevent ash from being emitted. When the thickness of the ringing material 11 on the inner wall of the rotary kiln is greater than 50mm, the eccentricity is adjusted by adjusting the lifting device 10 to form unequal circumferential gaps, thereby squeezing and grinding the ringing material 11. When the thickness of the ringing material 11 is less than 50mm, the lifting device 10 between the upper and lower support plates can be used to adjust the centers of the inner and outer rings and the center of the rotary kiln to the same circle.

[0034] This invention solves the ring-forming problem in metallurgical rotary kilns by drilling multiple holes along the circumference of the kiln body and inserting freely movable connecting rods into each hole. The connecting rods are fixedly connected at both ends to an inner ring and an outer ring with a concentric structure, placed inside and outside the kiln. The outer ring sits on a support roller below the mechanism, while the inner ring is placed inside the kiln body. By adjusting the lifting device between the upper and lower support plates of the support roller, a certain eccentricity d can be created between the centers of the outer and inner rings and the center of the rotary kiln. At this time, an eccentric gap is formed between the outer wall of the inner ring and the inner wall of the kiln. Within this gap, the ring-forming material falls off due to the squeezing and grinding action between the inner wall of the kiln and the outer wall of the inner ring, thus solving the ring-forming problem in metallurgical rotary kilns. This mechanism can solve the ring-forming phenomenon commonly seen in the roasting and direct reduction processes during laterite nickel ore smelting, reducing the difficulty of smelting caused by raw materials and operations, and is suitable for promotion in the laterite nickel ore smelting industry.

[0035] Because of the certain eccentricity, the cooling method adopted at the drilling point is that the outer ring and the connecting rod are provided with ventilation holes, and cold air can enter the connecting rod through the drilling holes of the outer ring. The inner ring is provided with air cooling pipes along the circumferential direction, which can be connected through the inner diameter of the connecting rod. The outer ring is provided with air intakes around its perimeter.

[0036] Example 1

[0037] A certain nickel-iron plant uses the rotary kiln + electric arc furnace (RKEF) process technology to smelt laterite nickel ore. The parameters of its laterite nickel ore roasting rotary kiln are: diameter 5.2 meters, length 120 meters, and average thickness of refractory material on the inner wall of the kiln shell 0.3 meters. Along the length of the rotary kiln, the temperature inside the kiln varies from 500 to 1200℃. The burner is a pulverized coal burner, which extends into the rotary kiln about 20 meters. The ring-shaped area is located 25-26 meters into the kiln from the burner end, and the ring is about 1 meter wide along the circumference.

[0038] This invention is installed on this rotary kiln. Two rows of holes are drilled along the circumference at a depth of 25-26 meters from the burner end of the rotary kiln. Each row has 12 holes evenly distributed along the circumference, and the distance between the two rows is 0.5 meters.

[0039] A high-temperature alloy inner ring 7 is installed inside the circumference of the rotary kiln shell. The inner diameter of the inner ring 7 is 3.9 meters, the thickness is 80 mm, and the width is 0.8 meters. A 1Gr13 alloy outer ring 5 is installed outside the circumference of the rotary kiln shell.

[0040] Next, install the connecting rod, roller assembly, and lifting device, among other components.

[0041] In this embodiment, the lower eccentricity of the adjustment mechanism is set to 50mm before initial use. The automation program is set to operate for 5 minutes every hour, with the remaining time set to concentricity without eccentricity.

[0042] Example 2:

[0043] A nickel-iron plant uses a rotary kiln direct reduction process to smelt laterite nickel ore. The parameters of its laterite nickel ore roasting rotary kiln are: diameter 3.8 meters, length 90 meters, and an average refractory material thickness of 0.3 meters on the inner wall of the kiln. Along the length of the kiln, the temperature inside ranges from 600 to 1350℃. The burner is a natural gas burner, extending approximately 16 meters into the kiln. The ring-like area extends 19-19.5 meters into the kiln from the burner end, with a circumferential width of approximately 0.5 meters.

[0044] This invention is installed on this rotary kiln. Two rows of holes are drilled along the circumference at a depth of 19-20 meters from the burner end of the rotary kiln. Each row has 9 holes evenly distributed along the circumference, and the distance between the two rows is 0.3 meters.

[0045] A high-temperature alloy inner ring 7 is installed inside the circumference of the rotary kiln shell. The inner ring 7 has an inner diameter of 2.6 meters, a thickness of 50 mm, and a width of 0.5 meters. An alloy outer ring 5 is installed outside the circumference of the rotary kiln shell.

[0046] Next, install the connecting rod, roller assembly, and lifting device, among other components.

[0047] In this embodiment, the upper eccentricity of the adjustment mechanism is set to 100mm, and it is put into use at the beginning. The automation program is set to run twice every hour, for 5 minutes each time, and the rest of the time is set to concentricity without eccentricity.

Claims

1. An anti-ringing mechanism for a metallurgical rotary kiln, characterized in that, The system includes a lower support plate (1), an upper support plate (2) is provided above the lower support plate (1) via a lifting device (10), and a support roller (4) is provided on the front and rear sides of the upper support plate (2) via a support roller bearing seat (3). An outer ring (5) is placed on the support roller (4), and an inner ring (7) is coaxially provided inside the outer ring (5) via a connecting rod (6). The inner ring (7) is located inside the rotary kiln body (9), and the outer ring (5) is located outside the rotary kiln body (9). The connecting rod (6) moves through the corresponding strip-shaped through hole on the rotary kiln body (9).

2. The anti-ringing mechanism for a metallurgical rotary kiln according to claim 1, characterized in that, The lower support plate (1) is provided with a guide rod (8), which moves through the corresponding through hole on the upper support plate (2).

3. The anti-ringing mechanism for a metallurgical rotary kiln according to claim 1, characterized in that, The lifting device (10) is a hydraulic cylinder, and there are four of them, which are distributed at the four corners of the lower support plate (1).

4. The anti-ringing mechanism for a metallurgical rotary kiln according to claim 1, characterized in that, The lifting device (10) is a worm gear jack.

5. The anti-ringing mechanism for a metallurgical rotary kiln according to claim 1, characterized in that, A dust cover is installed at the opening on the outer wall of the rotary kiln cylinder (9) on the connecting rod (6).

6. The anti-ringing mechanism for a metallurgical rotary kiln according to claim 1, characterized in that, Two rows of connecting rods (6) are arranged radially between the outer ring (5) and the inner ring (7), with multiple connecting rods (6) evenly distributed along the circumferential direction in each row.

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