Anti-coating short kiln continuous self-overflow rotary kiln
By using a reverse-sloping short kiln design and controlling the temperature inside the kiln, the problem of ring formation in traditional rotary kilns has been solved, enabling efficient and stable production of reduced iron powder and improving equipment operating efficiency and product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Filing Date
- 2026-06-04
- Publication Date
- 2026-07-10
AI Technical Summary
Traditional rotary kilns suffer from ring formation during the preparation of reduced iron powder, resulting in poor production continuity, high maintenance costs, unstable product quality, and incomplete material reduction.
The kiln adopts a reverse inclined short kiln design, eliminating the preheating zone and cooling zone. The kiln components are arranged at an inclined angle, and the material is discharged through quantitative feeding and overflow. The temperature inside the kiln is kept above the ring agglomeration point. Combined with refractory brick layers and fish scale seals, continuous high-temperature reduction is achieved.
Extend equipment operating cycle, improve production capacity and product quality stability, reduce operation and maintenance costs, increase metallization rate and iron powder purity, adapt to various iron-containing raw materials, and achieve efficient and stable production of reduced iron powder.
Smart Images
Figure CN122360101A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metallurgical and chemical equipment, and more specifically, to a reverse-inclined horizontal short kiln anti-ringing continuous self-overflow rotary kiln. Background Technology
[0002] Reduced iron powder is widely used in powder metallurgy, chemical industry, welding, and environmental protection. Currently, the mainstream industrial process for preparing reduced iron powder is the high-temperature solid-phase reduction process using rotary kilns. Existing traditional rotary kilns generally have the following inherent structural and technological defects: 1. The length of traditional reduced iron powder rotary kilns is mostly between 40 and 80 meters. Along the kiln body axis, they are divided into a preheating zone, a heating zone, a high-temperature reduction zone, and a cooling zone, resulting in a significant temperature gradient. The temperature is low at the feed end, locally high in the middle section, and low at the discharge end. 2. Traditional rotary kilns are installed with a positive tilt at the feed end and a low discharge end. The material rolls from the feed end to the discharge end by relying on the tilting and rotation of the kiln body.
[0003] Because of the medium-low temperature transition zone within the kiln, iron-containing materials in a semi-molten state easily adhere to the refractory lining, forming kiln skin, rings, and nodules. The continuous thickening of these rings reduces the effective flow diameter, clogs the kiln body, and disrupts the reducing atmosphere, necessitating frequent kiln shutdowns for ring cleaning and removal. This results in extremely poor production continuity, high maintenance costs, and in severe cases, red-hot kilns, refractory material detachment, and equipment failure. Existing technologies primarily address ring formation passively through raw material ratios, additives, segmented temperature control, and online ring scraping, but none of these methods can fundamentally eliminate the ring formation mechanism. Traditional long kilns rely on gravity-driven material transport, where the material's movement speed is affected by multiple factors including inclination angle, rotation speed, ring formation, particle size, and moisture content. Some materials pass through the high-temperature zone too quickly, resulting in incomplete reduction, while others remain for too long, leading to over-burning and oxidation. This results in low product metallization rates, poor batch consistency, and difficulty in maintaining stable production capacity and quality.
[0004] Therefore, we have made improvements to this and proposed a reverse-sloping horizontal short kiln anti-ringing continuous self-overflow rotary kiln. Summary of the Invention
[0005] In view of the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide a reverse inclined horizontal short kiln anti-ring continuous self-overflow rotary kiln.
[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: A reverse-inclined, horizontal, short-kiln, anti-ringing, continuous self-overflowing rotary kiln includes a kiln body assembly. The kiln body assembly includes a kiln body shell, an inner lining layer fixedly installed inside the kiln body shell, an annular opening fixedly installed at one end of the kiln body shell, a kiln head hood rotatably connected to the end of the kiln body shell away from the annular opening, and a kiln tail hood rotatably connected to the end of the kiln body shell located at the annular opening. A feeding cylinder is fixedly installed at the center of the upper surface of the kiln tail hood. The kiln body assembly is inclined at 1 to 7 degrees to the ground, and the end of the kiln body assembly located at the annular opening is at a lower position.
[0007] Preferably, the inner wall of the annular constriction is configured as a funnel shape, and the inner diameter of the annular constriction at the end away from the outer shell of the kiln is smaller than that at the end closer to the outer shell of the kiln.
[0008] Preferably, the inner lining layer is a high-temperature refractory brick layer, and friction wheels are fixedly sleeved on both sides of the center of the outer wall of the kiln body.
[0009] Preferably, fish scale sealing layers are provided at both ends of the outer wall of the kiln body where it connects to the kiln head cover and the kiln tail cover.
[0010] Preferably, the lowest point of the inner diameter of the annular opening is higher than the lowest point of the inner diameter of the end of the kiln body outer shell away from the annular opening.
[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: By eliminating the preheating and cooling zones and adopting a short kiln design with kiln components arranged at an anti-tilted angle, materials cannot move towards the discharge end by gravity. Instead, they are continuously and quantitatively fed through a feeding device, causing the liquid level inside the kiln to rise continuously. Once the liquid level reaches the lowest point of the inner wall of the kiln head hood, it automatically overflows and is discharged. The entire kiln is a single high-temperature reduction chamber, and the working temperature inside the kiln is consistently higher than the material's agglomeration point, reducing the probability of semi-molten adhesion and agglomeration. This significantly extends the continuous operation cycle of the equipment, eliminating the need for frequent kiln shutdowns for agglomeration cleaning, thus improving capacity utilization. The reduction efficiency is high, product quality is stable, residence time is controllable, and the material is fully reduced at high temperatures, achieving a metallization rate of over 90%. Batch consistency is good, and iron powder purity is high. The short kiln body results in low overall cost, significantly reducing maintenance, spare parts, and labor costs. The simple structure, low failure rate, and wide adaptability eliminate the need for complex multi-temperature zone control systems. It can be adapted to various iron-containing raw materials such as iron ore powder, red mud, copper tailings, and steel slag, and has high solid waste resource utilization value. This opens up a new process route for short-kiln high-temperature self-overflow reduction. Attached Figure Description
[0012] Figure 1 A flowchart of a reverse inclined horizontal short kiln anti-ringing continuous self-overflow rotary kiln provided in this application; Figure 2 A flowchart of a reverse inclined horizontal short kiln anti-ringing continuous self-overflow rotary kiln provided in this application; Figure 3 A flowchart of a reverse inclined horizontal short kiln anti-ringing continuous self-overflow rotary kiln provided in this application; Figure 4 The flowchart provided in this application describes a reverse-sloping horizontal short kiln with continuous self-overflowing anti-ringing rotary kiln.
[0013] In the diagram: 1. Kiln head hood; 2. Kiln body assembly; 3. Kiln tail hood; 4. Feeding cylinder; 5. Friction wheel; 201. Kiln outer shell; 202. Annular closure; 203. Inner lining. Detailed Implementation
[0014] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0015] A reverse-inclined, horizontal, short-kiln anti-ringing, continuous self-overflowing rotary kiln includes a kiln body assembly 2. The kiln body assembly 2 includes a kiln body shell 201. An inner lining layer 203 is fixedly installed inside the kiln body shell 201. An annular constriction 202 is fixedly installed at one end of the kiln body shell 201. A kiln head cover 1 is rotatably connected to the end of the kiln body shell 201 away from the annular constriction 202. A kiln tail cover 3 is rotatably connected to the end of the kiln body shell 201 located at the annular constriction 202. A feeding cylinder 4 is fixedly installed at the center of the upper surface of the kiln tail cover 3. The kiln body assembly 2 is inclined at 1~7° to the ground. The end of the kiln body assembly 2 located at the annular constriction 202 is in a lower position.
[0016] First, iron powder is fed into the feeding cylinder 4 via a screw conveyor and belt conveyor. Hot flue gas is introduced into the feeding cylinder 4 using existing waste heat recovery devices. Multiple opposing inclined baffles are installed inside the feeding cylinder 4 to slow the falling speed of the iron powder, allowing it to fully contact and preheat with the hot flue gas. By setting the kiln body component 2 at an angle completely opposite to the traditional forward inclination, the kiln tail is lower than the kiln head, and the discharge port is higher than the feed port, preventing the material from automatically rolling down to the discharge end by gravity. Through quantitative and continuous feeding via the feeding cylinder 4, the liquid level of the iron powder material inside the kiln body component 2 gradually rises until it reaches the kiln shell 201. Located at the lowest point of the inner wall of one end of the kiln head hood 1, the material automatically overflows and is discharged. The qualified material for high-temperature reduction automatically and continuously overflows. Through the special overflow discharge method, the residence time of most materials inside the high-temperature kiln body component 2 tends to be average, thereby ensuring sufficient reduction and continuous discharge. In addition, the entire kiln body component 2 adopts a short kiln body design that eliminates the preheating zone and cooling zone. The entire kiln is a single high-temperature reduction chamber. The working temperature inside the kiln is higher than the material's ring agglomeration point throughout the process. There is no medium-low temperature transition zone. This avoids the existence of medium-low temperature transition zones in the kiln body of traditional rotary kilns. Iron-containing materials are very easy to adhere to the refractory lining in a semi-molten state, forming kiln skin, rings, and nodules.
[0017] Furthermore, the inner wall of the annular constriction 202 is set in a funnel shape, and the inner diameter of the annular constriction 202 at the end away from the kiln shell 201 is smaller than that at the end close to the kiln shell 201.
[0018] Furthermore, the inner lining layer 203 is set as a high-temperature refractory brick layer, and friction wheels 5 are fixedly sleeved on both sides of the center of the outer wall of the kiln shell 201.
[0019] By using an external driving source to drive the friction wheel 5 to rotate the kiln body component 2, the iron powder material inside the kiln can be evenly rolled, heated evenly, and fully contacted with the reducing atmosphere, thereby improving the consistency of reduction.
[0020] Furthermore, fish-scale sealing layers are provided at both ends of the outer wall of the kiln body shell 201 where it connects to the kiln head cover 1 and the kiln tail cover 3.
[0021] The kiln shell 201 is sealed by a fish scale sealing layer. The fish scale seal utilizes the flexible and adaptive properties of multiple elastic sheets to tightly fit the radial runout and axial movement of the rotary kiln caused by thermal expansion and contraction and operation. The fish scale sealing layer not only prevents the overflow of high-temperature dust and the intake of cold air inside the kiln, but also has the advantages of high temperature resistance, wear resistance, simple structure and convenient maintenance.
[0022] Furthermore, the lowest point of the inner diameter circumference of the annular constriction 202 is higher than the lowest point of the inner diameter circumference of the end of the inner wall of the kiln shell 201 that is far away from the annular constriction 202.
[0023] The hot flue gas is introduced into the feeding cylinder 4 using existing waste heat recovery devices. Multiple opposing inclined baffles are installed inside the feeding cylinder 4 to slow the falling speed of the iron powder, allowing the iron powder to fully contact and preheat with the hot flue gas. After being heated at high temperature by the external device of the kiln body assembly 2 and melting inside the kiln body assembly 2, the iron powder is continuously fed downwards through the feeding cylinder 4, causing the liquid level inside the kiln body assembly 2 to rise. After the liquid level rises, it is caught by the annular constriction 202, preventing the molten liquid from flowing out along the end of the kiln shell 201 located inside the kiln tail hood 3. The lowest point of the inner diameter of the annular constriction 202 is higher than the inner diameter of the end of the kiln shell 201 furthest from the annular constriction 202. The design of the lowest point of the kiln allows the molten material to be fully tumbled and heated by the rotation of the kiln shell 201, and then automatically overflows from the kiln head hood 1. Compared with the existing technology where the feed inlet is high and the discharge outlet is low, this design can prolong the time that iron powder stays in the kiln shell 201, avoiding the problem of insufficient reduction caused by some iron powder rolling down quickly and being heated for a short time. Combined with the short kiln design of the device without a preheating zone and cooling zone, this design can avoid the existence of a medium-low temperature transition zone in the kiln, which would cause iron-containing materials to easily adhere to the inner lining 203 in a semi-molten state, resulting in the formation of kiln skin, rings, and nodules inside the kiln shell 201, requiring frequent kiln shutdowns for cleaning.
[0024] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.
[0025] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.
Claims
1. A reverse-sloping, horizontal, short-kiln, continuous self-overflowing rotary kiln for preventing ring formation, characterized in that, The kiln assembly (2) includes a kiln shell (201), an inner lining (203) is fixedly installed inside the kiln shell (201), an annular opening (202) is fixedly installed at one end of the kiln shell (201), a kiln head cover (1) is rotatably connected to the end of the kiln shell (201) away from the annular opening (202), a kiln tail cover (3) is rotatably connected to the end of the kiln shell (201) located at the annular opening (202), a feeding cylinder (4) is fixedly installed at the center of the upper surface of the kiln tail cover (3), the kiln assembly (2) is inclined at 1~7° to the ground, and the end of the kiln assembly (2) located at the annular opening (202) is located at a low position.
2. The reverse inclined horizontal short kiln anti-ringing continuous self-overflow rotary kiln according to claim 1, characterized in that, The inner wall of the annular constriction (202) is configured as a funnel shape, and the inner diameter of the annular constriction (202) at the end away from the kiln shell (201) is smaller than that at the end close to the kiln shell (201).
3. A reverse-sloping horizontal short kiln anti-ringing continuous self-overflow rotary kiln according to claim 1, characterized in that, The inner lining layer (203) is set as a high temperature refractory brick layer, and friction wheels (5) are fixedly sleeved on both sides of the center of the outer wall of the kiln body shell (201).
4. A reverse-sloping horizontal short kiln anti-ringing continuous self-overflow rotary kiln according to claim 1, characterized in that, Fish scale sealing layers are provided at the connection points between the outer walls of the kiln body shell (201) and the kiln head cover (1) and the kiln tail cover (3).
5. A reverse-sloping horizontal short kiln anti-ringing continuous self-overflow rotary kiln according to claim 1, characterized in that, The lowest point of the inner diameter of the annular constriction (202) is higher than the lowest point of the inner diameter of the end of the kiln shell (201) away from the annular constriction (202).