A leak-proof structure at the bottom of the combustion chamber of a belt roaster

Abstract

This utility model discloses a seepage-proof structure at the bottom of the combustion chamber of a belt calciner, belonging to the technical field of belt calciners. It includes a working liner and a permanent liner. The working liner is positioned above the permanent liner and covers its surface. The working liner has a sloping structure with a higher inner surface and a lower outer surface, with a slope ranging from 0° to 8°. This utility model uses a partially or completely consumable working liner to replace the traditional seepage-proof layer structure, resulting in strong ash and slag resistance, low cost, and periodic removal along with the ash and slag. The sloping structure facilitates the external blowing of ash and slag or the outflow of molten slag.

Description

Technical Field

[0001] This utility model belongs to the technical field of belt roasting machines, and particularly relates to a seepage-proof structure at the bottom of the combustion chamber of a belt roasting machine. Background Technology

[0002] Belt roasters are currently one of the most common furnace types for iron ore powder to pelletize. To ensure continuous and controllable furnace temperature and prevent direct flame burning of the pellets, a series of combustion chambers are distributed on both sides of the furnace body. The combustion chambers are constructed of refractory bricks, with burners at each end. The flame burns in the combustion chamber, and the reheated air from the upper part of the combustion chamber is reheated in the combustion chamber before entering the furnace to heat the pellets. The furnace charge dust and impurities in the combustion gas carried in the reheated air are burned to form slag ash, which is deposited at the bottom of the combustion chamber.

[0003] The slag in the combustion chamber is highly corrosive with an alkaline content, and its CaO / SiO2 ratio is approximately 2.2 (typical composition examples are shown in Table 1). Prolonged exposure to high temperatures can erode the combustion chamber materials, severely impacting their service life. To prevent slag erosion, current methods involve laying a layer of slag-proof material at the bottom of the combustion chamber—a seepage-proof layer. However, existing seepage-proof layers are integral and permanent. In practice, due to adhesion to the slag ash, when the slag ash accumulates to a certain level and needs cleaning, the seepage-proof layer is also damaged and requires removal.

[0004] Table 1 Examples of typical sediment composition

[0005]

[0006] In addition, for many years, the combustion chamber anti-seepage layer material has been made of chromium corundum rammed earth, with Al2O3+Cr2O3≥90%, of which Cr2O3 content is about 30%, which is a high chromium material. During use, Cr2O3 is converted into Cr. 6+ Hexavalent chromium is potentially carcinogenic and readily soluble in water. The impermeable material is a consumable; after adhering to ash and slag, it is removed along with the ash and slag once the ash and slag have settled to a certain extent. This waste material contains chromium. 6+ The material has a high chromium content and needs to be treated as high-risk hazardous waste, which puts significant pressure on environmental protection. It is also a restricted material internationally. In addition, the high price and high proportion of chromium oxide in the seepage prevention material lead to a high cost.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0008] To address the technical problem that existing anti-seepage structures in the combustion chamber of calciners are prone to ash and slag adhesion, leading to damage to the anti-seepage structure and the generation of hazardous waste, a novel anti-seepage structure for the bottom of the combustion chamber of a belt-type calciner is provided.

[0009] The present invention provides a bottom seepage prevention structure for the combustion chamber of a belt roaster, comprising a working liner and a permanent liner. The working liner is disposed above the permanent liner and covers the surface of the permanent liner. The working liner has a sloping structure with a higher inner surface and a lower outer surface, and the slope of the working liner is in the range of 0 < i ≤ 8°.

[0010] In some embodiments, the permanent liner is disposed at the bottom of the combustion chamber, and the sidewalls of the permanent liner are in close contact with the inner wall of the combustion chamber;

[0011] And / or, the working liner is removably covered over the surface of the permanent liner, with its sidewalls in seamless contact with the inner wall of the combustion chamber.

[0012] In some embodiments, the slope of the working liner ranges from 5 to 8°;

[0013] And / or, the thickness of the working liner is 10-80 mm.

[0014] In some embodiments, the permanent liner is a horizontal structure or a sloping structure that is higher on the inside and lower on the outside.

[0015] In some embodiments, when the permanent liner has a sloping structure, its slope is consistent with that of the working liner.

[0016] In some embodiments, the working liner is made of a different material than the permanent liner and is in a layered state.

[0017] In some embodiments, the working lining material is an Al2O3-MgO-Cr2O3-based low-chromium material or an Al2O3-MgO spinel-based chromium-free material. In the Al2O3-MgO-Cr2O3-based low-chromium material, Al2O3-MgO-Cr2O3 ≥ 85% and Cr2O3 ≤ 15%. In the Al2O3-MgO spinel-based chromium-free material, Al2O3-MgO ≥ 85% and Cr2O3 ≤ 0.5%.

[0018] In some embodiments, the permanent lining is an Al2O3-MgO-Cr2O3 refractory material, preferably, the permanent lining material is chromium corundum or corundum mullite.

[0019] In some embodiments, the working liner is made of the same material as the permanent liner and is either layered or a single unit.

[0020] In some embodiments, both the working liner and the permanent liner are made of Al2O3-MgO-Cr2O3-based low-chromium materials or Al2O3-MgO spinel-based chromium-free materials. In the Al2O3-MgO-Cr2O3-based low-chromium materials, Al2O3-MgO-Cr2O3 ≥ 85% and Cr2O3 ≤ 15% are present. In the Al2O3-MgO spinel-based chromium-free materials, Al2O3-MgO ≥ 85% and Cr2O3 ≤ 0.5% are present.

[0021] Compared with the prior art, the technical effects achieved by this utility model are as follows:

[0022] This utility model uses a partially or completely consumable working lining to replace the traditional anti-seepage layer structure. It has strong resistance to ash and slag, low cost, and can be removed periodically along with the ash and slag. The high-to-low slope structure facilitates the external blowing of ash and slag or the external flow of molten slag.

[0023] The selection of low-chromium or chromium-free materials for the seepage barrier layer can significantly reduce material costs while taking into account both slag erosion resistance and high-temperature performance. It also reduces adhesion to slag and ash, making it easier to remove slag and ash. Furthermore, it is less likely to generate hazardous waste with high chromium content when in contact with slag and ash, making it more environmentally friendly. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the anti-seepage material structure at the bottom of the combustion chamber of a belt roaster provided in one embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the anti-seepage material structure at the bottom of the combustion chamber of a belt roaster provided in another embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the anti-seepage material structure at the bottom of the combustion chamber of the belt roaster provided in the third embodiment of the present invention;

[0027] Among them, 1-working lining; 2-permanent lining; 3-complete replacement structure. Detailed Implementation

[0028] The technical solution of this utility model is described below with reference to the accompanying drawings and specific embodiments. It should be understood that the existence of other methods and steps before and after the combined steps mentioned in this utility model does not preclude the presence of other methods and steps, or the insertion of other methods and steps between these explicitly mentioned steps. It should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of this utility model. Unless otherwise stated, the numbering of each method step is only for the purpose of identifying each method step, and not for limiting the order of each method or defining the scope of implementation of this utility model. Changes or adjustments to their relative relationships, without substantial changes to the technical content, can also be considered as within the scope of implementation of this utility model.

[0029] The raw materials and instruments used in the examples are not subject to any specific restrictions on their source; they can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0030] Example:

[0031] A leak-proof structure at the bottom of the combustion chamber of a belt roaster, such as Figure 1 As shown, it includes a working liner 1 and a permanent liner 2. The working liner 1 is disposed above the permanent liner 2 and is removably covered on the surface of the permanent liner 2. Its sidewalls are in seamless contact with the inner wall of the combustion chamber. The permanent liner 2 is disposed at the bottom of the combustion chamber and is in close contact with the inner wall of the combustion chamber.

[0032] In one embodiment, the working liner has a sloping structure with a higher inner surface and a lower outer surface, with a slope of less than or equal to 8°, while the permanent liner 2 has a horizontal structure.

[0033] In one embodiment, the slope of the working liner is in the range of 5 to 8°.

[0034] In one embodiment, the thickness of the working liner is 10-80 mm.

[0035] In one embodiment, the working lining and the permanent lining are made of different materials and are in a layered state. The working lining is made of Al2O3-MgO-Cr2O3-based low-chromium material or Al2O3-MgO spinel-based chromium-free material. In the Al2O3-MgO-Cr2O3-based low-chromium material, Al2O3-MgO-Cr2O3 ≥ 85%, wherein 0.5% ≤ Cr2O3 ≤ 15%. In the Al2O3-MgO spinel-based chromium-free material, Al2O3-MgO ≥ 85%, and Cr2O3 ≤ 0.5%. The permanent lining is an Al2O3-MgO-Cr2O3-based refractory material. Specifically, the permanent lining material is chromium corundum or corundum mullite.

[0036] The working lining (replacement layer) is in constant contact with ash and slag, and is subject to ash erosion. Low-chromium or chromium-free materials are selected to balance slag erosion resistance and high-temperature performance while effectively reducing material costs. The working lining, being in contact with ash and slag, has strong ash and slag resistance, is low in cost, and can be periodically removed along with the ash and slag. The permanent lining has strong high-temperature resistance and ash and slag resistance, providing secondary protection. Due to the layered interface with the working lining, it is generally not touched during ash and slag cleaning, allowing it to remain long-term and provide protection.

[0037] In another embodiment, such as Figure 2 As shown, the working liner 2 also has a sloping structure with a higher inner surface and a lower outer surface. The slope is consistent with that of the working liner, and the slope is below 8°, preferably 5° to 8°.

[0038] In the third implementation, such as Figure 3As shown, the working liner and the permanent liner are made of the same material and are either layered or a single, fully replaced structure 3. The working liner and the permanent liner are made of Al2O3-MgO-Cr2O3-based low-chromium materials or Al2O3-MgO spinel-based chromium-free materials. In the Al2O3-MgO-Cr2O3-based low-chromium materials, Al2O3-MgO-Cr2O3 ≥ 85%, of which 0.5% ≤ Cr2O3 ≤ 15%. In the Al2O3-MgO spinel-based chromium-free materials, Al2O3-MgO ≥ 85%, and Cr2O3 ≤ 15%. 3, ≤0.5%. By using low-chromium or chromium-free materials to completely replace the Al2O3-SiO2-Cr2O3 refractory materials in the existing technology, the cost of materials is significantly reduced while taking into account slag erosion resistance.

[0039] The actual operating conditions of the combustion chamber of the belt roaster include:

[0040] 1) The temperature inside the combustion chamber is around 1600℃;

[0041] 2) Regenerated air at 600-1100℃ flows through the combustion chamber and is heated to 800-1350℃;

[0042] 3) The regenerated air contains a small amount of dust, the main components of which are FeO, Fe2O3, CaO, Al2O3, SiO2 and other components;

[0043] 4) Slag deposition, the main components are described in the background section;

[0044] From both a technical and environmental perspective, it is essential to replace refractory materials for belt calciners with chromium-free alternatives.

[0045] The aforementioned low-chromium materials, chromium-free materials, and Al2O3-SiO2-Cr2O3-based refractory materials are all general materials in the prior art that conform to the technical solution of this utility model.

[0046] This invention involves a new material selection and design for the anti-seepage material of the combustion chamber of a belt roaster. While ensuring the anti-seepage effect, it aims to reduce the amount of Cr2O3 used as much as possible, and even completely replace it.

[0047] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the present invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the present invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the present invention, as well as various different choices and variations. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A seepage-proof structure at the bottom of the combustion chamber of a belt roaster, characterized in that, It includes a working liner and a permanent liner. The working liner is disposed above the permanent liner and covers the surface of the permanent liner. The working liner has a sloping structure with the inside higher than the outside, and the slope of the working liner is in the range of 0 < i ≤ 8°.

2. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 1, characterized in that, The permanent liner is disposed at the bottom of the combustion chamber, and the sidewalls of the permanent liner are in close contact with the inner wall of the combustion chamber.

3. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 1, characterized in that, The slope of the working liner is in the range of 5 to 8°; And / or, the thickness of the working liner is 10-80 mm.

4. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 1, characterized in that, The permanent lining has a horizontal structure or a sloping structure that is higher on the inside and lower on the outside.

5. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 1, characterized in that, When the permanent lining has a sloping structure, its slope is consistent with that of the working lining.

6. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 1, characterized in that, The working liner is made of a different material than the permanent liner and is in a layered state.

7. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 6, characterized in that, The permanent lining is an Al2O3-MgO-Cr2O3 series refractory material.

8. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 7, characterized in that, The permanent lining material is chrome corundum or corundum mullite.

9. The anti-seepage structure at the bottom of the combustion chamber of the belt roaster according to claim 1, characterized in that, The working liner is made of the same material as the permanent liner and is either layered or a single unit.

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