Lining structure of ferronickel rotary kiln

Abstract

The utility model provides a ferronickel rotary kiln lining structure which comprises a prefabricated part module, an anchoring module and a heat preservation module, the anchoring module is installed in a furnace shell of a rotary kiln and comprises an anchoring net and an anchoring rib, one end of the anchoring rib is fixed to the anchoring net, and the anchoring net is fixed to the furnace shell through spot welding; the anchoring net is arranged on the inner side of the furnace shell, the heat preservation modules are tightly attached to the inner side of the furnace shell and clamped and embedded between grids of the anchoring net, 6-10 prefabricated part modules are installed on the annular portion of the rotary kiln, preformed holes corresponding to the anchoring ribs are formed in the prefabricated part modules, and gaps between the preformed holes and gaps between the prefabricated part modules are filled with castable. According to the utility model, the prefabricated part module which is provided with the reserved anchoring holes and is of an arc-shaped structure is used as a core, and the networking framework type anchoring module and the cast-in-place anchoring part are used as the core for anchoring, so that the rapid installation of the rotary kiln is realized, and the service life is prolonged.

Description

Technical Field

[0001] The utility model relates to a ferronickel rotary kiln lining, in particular to a ferronickel rotary kiln lining structure. Background Art

[0002] The nickel-iron rotary kiln produced by roasting laterite ore includes a furnace shell and a lining structure. The lining structure needs to use refractory materials. The design of the lining structure generally includes the following: refractory brick structure, castable structure, prefabricated structure, and prefabricated composite castable structure. Among them, the refractory brick structure has no anchors. Due to the rotation of the rotary kiln and other factors, it is easy to collapse bricks under long-term use, so it is gradually replaced by the castable structure. The construction efficiency of the castable structure is high, but because the castable needs to be mixed with water on site, the quality control during the construction process is greatly affected by the construction period and personnel factors, and the expected effect is often not achieved. The prefabricated structure can replace the on-site pouring construction method of the castable structure, but if the prefabricated structure is used, the on-site installation is difficult. Due to factors such as the manufacturing error of the kiln body structure, it is easy to cause a situation where it is difficult to install tightly, and the installation gap between the prefabricated parts is difficult to meet the design requirements due to the manufacturing process and actual conditions. Therefore, a prefabricated composite castable structure using prefabricated parts and castables appears, that is, some prefabricated structures are designed, and the gaps are filled with castables during on-site installation.

[0003] There is often an insulation layer between the furnace shell and the lining structure. The material of the insulation layer is usually a lightweight refractory material. Therefore, during the operation of the rotary kiln, if the lining structure is deformed, the insulation layer is easily delaminated from the furnace shell due to stress, causing the furnace shell to turn red and the anchors to deform due to heat in the later stage of the rotary kiln, which affects production safety and reduces the service life of the lining structure. To avoid this situation, many nickel-iron rotary kilns are designed with anchoring structures, including anchoring brick structures, metal anchoring structures, and metal anchoring composite anchoring brick structures. The use temperature of the anchoring brick structure is high, but the production cycle is long and it cannot be produced on site. When facing the rotation of the rotary kiln and the impact of materials, it is easy to cause the anchoring brick to break and the lining structure to fall off. The metal anchor has a short production cycle and can be produced on site. Its disadvantage is that the use temperature is low. The metal anchor composite anchor brick structure theoretically plays a complementary role between the two anchor structures, but due to the limitation of the anchor position, the spacing between each anchor has doubled. In fact, it only neutralizes the advantages and disadvantages of the two anchor forms, and does not maximize the advantages of the two anchors.

[0004] In a nickel-iron rotary kiln lining structure with application number 201821408344.6, it is divided into a low-temperature zone, a medium-temperature zone and a high-temperature zone. The low-temperature zone, the medium-temperature zone and the high-temperature zone are all composed of a kiln shell, a casting material layer located on the inner side of the kiln shell, and an anchor hook for fixing the casting material layer. The anchor hook is fixed on the inner side of the kiln shell, and a lightweight refractory layer is arranged between the inner side of the kiln shell and the casting material layer. The casting material layer includes a working layer and a retaining layer. The retaining layer protrudes from the working layer and is arranged at intervals on the working layer. The working layer and the retaining layer use two anchor hooks of different sizes.

[0005] Although the above scheme improves the anchoring method of the lining structure, it ignores the impact of the castable construction. According to practical experience, there are problems with the construction process control of castables poured on site. The addition of water to the castable on site is affected by many factors and cannot meet the optimal requirements. The loading, transportation, and vibration processes during the construction process are complicated, and the labor intensity of the workers is relatively high. During the baking of the castable, as the amount and thickness of the castable increase, the baking difficulty of the castable also increases, and the baking time also needs to be extended, which ultimately leads to an extension of the construction period. In order to effectively resolve the contradiction between the rush to meet the construction deadline and the on-site pouring quality control, the workload of on-site pouring construction should be reduced, thereby truly reducing the construction time of the rotary kiln and increasing the service life of the rotary kiln. Utility Model Content

[0006] The utility model provides a lining structure of a nickel-iron rotary kiln, which is used to solve the defects of the lining of the nickel-iron rotary kiln currently used for laterite ore roasting production. The technical solution is as follows:

[0007] A lining structure of a nickel-iron rotary kiln comprises a prefabricated module, an anchoring module and a heat preservation module. The anchoring module is installed inside a furnace shell of the rotary kiln, the anchoring module comprises an anchoring mesh and an anchoring rib, one end of the anchoring rib is fixed to the anchoring rib; the heat preservation module is close to the inner side of the furnace shell and is embedded between the grids of the anchoring mesh. 6 to 10 prefabricated modules are installed in the annular part of the rotary kiln, the prefabricated modules are provided with reserved holes corresponding to the anchoring ribs, and the reserved holes and the gaps between the prefabricated modules are filled with castables.

[0008] A gap of 10-40 mm is provided between the prefabricated modules.

[0009] The anchoring parts used in the anchoring module include three types: straight ribs, arc ribs and anchoring ribs. The anchoring parts are made of stainless steel and have a diameter of 10-12 mm.

[0010] The straight ribs and arcuate ribs are welded to form a horizontally and vertically staggered anchoring net, the anchoring net is fixed on the furnace shell by spot welding, and the anchoring ribs are connected to the arcuate ribs of the welded anchoring net by screw holes or welding.

[0011] The surface of the anchor bar is coated with asphalt, and a 2-4 mm thick expansion cap is installed on the top or a tape of corresponding thickness is wrapped around it.

[0012] When installing the insulation module, it is necessary to avoid the anchoring ribs of the anchoring module. The insulation module is made of a 10mm-20mm thick arc-shaped nano insulation board and a 40-60mm thick fiber insulation board bonded by high-temperature glue. The nano insulation board is located between the furnace shell and the fiber insulation board.

[0013] The prefabricated module is made of a steel mold, and the prefabricated module is baked at 350-650° C. after demoulding and curing for 2-5 days.

[0014] The casting material and the prefabricated component module are made of the same material.

[0015] The lining structure of the nickel-iron rotary kiln is anchored by using a prefabricated module of an arc structure with reserved anchor holes as the core, and then using a networked skeleton anchor module and a cast-in-place anchor piece as the core, so as to achieve rapid installation of the rotary kiln and thus increase the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a main structural schematic diagram of the nickel-iron rotary kiln;

[0017] Figure 2 is a schematic diagram of the structure of the nickel-iron rotary kiln viewed from above;

[0018] Figure 3 is a schematic diagram of the cross-sectional structure of the ferronickel rotary kiln;

[0019] Figure 4 is a schematic diagram of the connection between the anchoring bars and the prefabricated blocks of the nickel-iron rotary kiln;

[0020] Figure 5 It is a structural schematic diagram of the anchor bar. DETAILED DESCRIPTION

[0021] The lining structure of the nickel-iron rotary kiln includes a prefabricated module, an anchoring module and an insulation module. The anchoring module is installed inside the furnace shell of the rotary kiln. The anchoring module includes an anchoring mesh and anchoring ribs. The anchoring mesh is fixed to the furnace shell by spot welding, and one end of the anchoring rib is fixed to the anchoring rib. The insulation module is close to the inner side of the furnace shell and is embedded in the grids of the anchoring mesh. 6 to 10 prefabricated modules are installed in the annular part of the rotary kiln. The prefabricated modules are provided with reserved holes corresponding to the anchoring ribs. The reserved holes and the gaps between the prefabricated modules are cast with casting materials of the same material as the prefabricated modules.

[0022] like Figure 1As shown, the rotary kiln 1 is cylindrical, and the furnace shell is made of steel. The size of each rotary kiln is different, the curvature of the cylinder is different, and the curvature size of the corresponding prefabricated module 2 is also different. Therefore, it is necessary to design and adjust the anchoring module and the prefabricated module 2 according to the curvature of the cylinder of the rotary kiln 1.

[0023] Furthermore, 6 to 10 prefabricated modules are usually designed in the annular part of the rotary kiln 1, and a gap of 10-40 mm is set between the prefabricated modules. In the length direction of the rotary kiln 1, the rotary kiln is divided into three temperature sections: low temperature zone, medium temperature zone and high temperature zone, and the prefabricated modules used in each temperature section are the same. (The prefabricated modules can be the same or different. In actual production, considering the price issue, the three temperature sections may be designed as prefabricated modules with inconsistent materials).

[0024] like Figure 2 and Figure 5 As shown, the anchoring module is also modularly designed according to the cylinder structure of the rotary kiln. The anchoring parts used include three types: straight ribs 4, arc ribs 5 and anchoring ribs 6, which are made of stainless steel and have a diameter of 10-12mm. They are formed separately and packaged in the same category. The anchoring parts are transported to the construction site in a centralized manner, and then the grid-shaped anchoring modules are installed on site. The straight ribs 4 and arc ribs 5 are welded to form a horizontal and vertical staggered anchoring net. The surface of the anchoring rib 6 is painted with asphalt, and a 3mm thick expansion cap is installed on the top or a tape of corresponding thickness is wrapped around it. The purpose is to buffer the thermal expansion stress of the metal. Otherwise, the metal end will push off the prefabricated module due to thermal expansion, and the volume expansion is large, so a gap is left by adding tape. The anchoring rib 6 is connected to the arc rib 5 of the welded anchoring net through screw holes or welding. During installation, the anchoring module is welded inside the furnace shell.

[0025] Combination Figure 4 As shown, the insulation module 7 is close to the inner side of the furnace shell and is embedded in the grids of the anchoring net. The anchoring ribs 6 are vertically distributed on the anchoring net, and the insulation module 7 can be understood as being laid flat between the anchoring nets, so the anchoring ribs 6 and the insulation module 7 should be in a vertical relationship. When installing the insulation module 7, the anchoring ribs 6 should be avoided. The insulation module 7 is made of a 10mm-20mm thick arc-shaped nano insulation board and a 40-60mm thick fiber insulation board by high-temperature adhesive bonding. The nano insulation board is located between the furnace shell and the fiber insulation board.

[0026] Combination Figure 5As shown, the prefabricated module is provided with a reserved hole corresponding to the anchoring bar of the anchoring module. The reserved hole is cast in situ using a casting material of the same material as the prefabricated module to realize the reserved hole anchor of the anchoring module. The prefabricated module is designed in size according to the rotary kiln shell, and a reserved hole corresponding to the position of the anchoring bar is reserved. Among them, the size of the reserved hole must ensure that the anchoring bar 6 can be smoothly inserted, has nothing to do with the insulation module, and should not be too large.

[0027] The prefabricated modules are made of steel molds and are baked at 350-650°C after demoulding and curing for 2-5 days.

[0028] The baked prefabricated modules are transported to the construction site, and the prefabricated modules are hoisted and placed in the position corresponding to the anchoring modules, so that each anchoring bar is in the middle of the reserved hole. In order, a row of prefabricated parts is installed along the length direction of the furnace body of the rotary kiln 1, and castables of the same material as the prefabricated modules are used for cast-in-place to realize the reserved hole anchors of the anchoring modules. After the castable hardens, the cylinder is rotated at a corresponding angle, and the next row of prefabricated modules is installed and cast in the same way. There is no specific limit on the number of prefabricated modules in each row. The size of the anchoring structure and the prefabricated parts need to be calculated in advance according to the size of the furnace body. For example, as shown in the figure, 16 through holes are set on each prefabricated part, corresponding to 16 anchoring bars, as long as the size is set. Furthermore, the prefabricated modules are marked according to the temperature section and installation location to make the installation orderly.

[0029] The gap between the prefabricated modules needs to be filled. The gap is the gap between the two prefabricated modules. If the two prefabricated modules are close together, the gap is very small. A pressure-resistant film is pasted on the gap between the two prefabricated modules, and isostatic self-flowing filler is used to fill it. The upper surface of the isostatic self-flowing filler contacts the pressure-resistant film. Restricted by the pressure-resistant film, the isostatic self-flowing filler will not overflow the gap. After the filler solidifies, the pressure-resistant film at the gap is torn off.

[0030] A pressure-resistant film is pasted on the gap between the two prefabricated modules to seal the gap and prevent the filling material from flowing out of the gap during pouring. The film can be torn off after hardening, or it can be left on. The pressure-resistant film will melt under the high temperature of baking later.

[0031] Finally, after the gaps between the prefabricated modules are filled and hardened, continue to cure at room temperature for 3 days. It can be baked to the high temperature section of 1100℃ in 5-7 days (generally, kiln baking has its own heating curve, which is low temperature first and gradually heats up over time), and then put into production. Alternatively, after baking to 350℃ within 3 days, bake with materials until normal production.

[0032] The technical solution of the present utility model is further described in detail below in conjunction with specific embodiments.

[0033] Step S11: For a Φ4.8×115m rotary kiln, design a prefabricated module according to the average circumferential division into 8 blocks and an arc length of 1.5m. Adjust the curvature of the variable prefabricated template of the prefabricated module to 45°, the outer arc length of the prefabricated module to 1890mm, and reserve a module interval of about 25mm. There are 4 types of prefabricated modules in total. The rotary kiln is divided into three temperature sections: low temperature zone, medium temperature zone and high temperature zone. Four materials are selected for prefabrication in each temperature section. The four materials are: the thickness of the prefabricated module is 230mm, the total number of modules is 616, and the material volume is 980 tons; the anchor module is 20.5 tons; the composite insulation module is 40 tons; the gap filling material of the prefabricated module is 15 tons.

[0034] Step S12: The anchoring module consists of arc ribs, straight ribs and anchor ribs. The arc ribs and straight ribs are made of 304 stainless steel with a diameter of 12 mm, and the anchor ribs are made of 310S stainless steel with a diameter of 10 mm. The surface of the anchor ribs is coated with asphalt, and a 3 mm thick expansion cap is installed on the top, which is connected to the welded anchor net through screw holes.

[0035] Step S13: The heat preservation module is made of a 20 mm thick arc-shaped nano heat insulation board and a 50 mm thick fiber heat insulation board by gluing with high temperature glue. The corresponding pre-cutting is performed according to the position of the anchor bar so that the anchor bar is avoided during installation.

[0036] Step S14: According to the conditions of each temperature section and each part, the prefabricated modules are marked after prefabrication to indicate the corresponding temperature section and installation part. The prefabricated modules are baked at 650°C after demolding and curing for 3 days. The baked prefabricated modules are transported to the construction site according to the installation sequence. The installed anchoring modules are rotated to a horizontal position, and the prefabricated modules are installed from the tail of the kiln. The prefabricated modules are hoisted and placed in the anchoring position so that each anchoring bar is located in the middle of the reserved holes reserved for the prefabricated modules. A row of prefabricated modules are placed along the length direction of the cylinder once, and the module casting material of the same material as the prefabricated modules is used for casting to realize the reserved hole anchors of the anchoring modules. After the casting material hardens, the cylinder is rotated to a corresponding angle, and the next row of prefabricated modules is installed in the same way.

[0037] Step S15: The gap between the two prefabricated parts is 10-40mm. Use high wind to blow the interface and gap to clean the dust during the installation process. Turn the caulking position to the bottom of the barrel and keep it level. Paste a pressure-resistant film with a width of 60mm on the top of the gap, and cover the surface of the pressure-resistant film with a fixed pressure plate. Seal the gap between the prefabricated parts, leaving only the exhaust holes above the bottom. Press the self-flowing filler into the gap between the prefabricated parts through the hole. Curing for 6 hours to solidify, turn the barrel to the next installation angle. And so on until the caulking is completed. After the casting material hardens, tear off the pressure-resistant film.

[0038] Step S16: The air temperature is 20°C, the temperature in the barrel is 15°C, and the curing is carried out for 3 days.

[0039] Step S17: Baking is performed for 7 days until the temperature reaches 1100° C. in the high temperature section, and then the material is put into production. The service life has been 6 years since it was put into production without major repairs.

[0040] The embodiment shortens the original construction time to 20 days; the baking time of the castable is shortened to 5 days, and the service life of the rotary kiln is increased to more than 6 years.

[0041] The utility model has the following features:

[0042] 1. The modular design of nickel-iron rotary kiln simplifies the structural design differences caused by cylinder differences and improves quality.

[0043] 2. By using the splicing template with variable curvature, templates with different curvatures can be provided. The splicing structure is easy to install and can be reused.

[0044] 3. The grid-shaped anchoring module forms the anchoring structure as a whole, which increases the anchoring performance.

[0045] 4. Cast-in-place reserved hole anchors replace anchor bricks. The prefabricated module has reserved holes for cast-in-place, which can realize the cast-in-place reserved hole anchor technology, so that the anchor material is consistent with or higher than the prefabricated module, improving the anchoring effect.

[0046] 5. The reserved holes reduce the amount of on-site pouring and reduce the impact of human factors on construction quality.

[0047] 6. The reserved hole anchors of the anchor module have small pouring volume and easy quality control.

[0048] 7. The reserved hole anchors of the anchor module have built-in metal anchor bars, which have improved thermal shock resistance and greatly improved fracture resistance compared to traditional anchor bricks.

[0049] 8. The reserved hole anchors of the anchor module eliminate the need for formwork support, thus improving construction efficiency.

[0050] 9. The reserved hole anchors of the anchor module are cast on site, so there is no need to consider the ordering cycle of the anchor bricks.

[0051] 10. The reserved hole anchors of the anchor module can achieve the same material technology as the prefabricated module, avoiding the structural stress concentration problem caused by the difference between the anchor bricks and the casting body.

[0052] 11. The insulation layer module is prefabricated according to the anchoring module to improve installation efficiency, improve production quality and reduce material waste.

[0053] 12. The gap between the two prefabricated modules is sealed by pasting a certain width of anti-pressure film, and the surface of the film is covered with a fixed pressure plate. The film itself can resist self-flowing fillers and other extrusion and scratches without cracking or falling off.

[0054] 13. Use isostatic self-flowing filler to achieve self-flow and pressure compaction.

Claims

1. A ferronickel rotary kiln lining structure, characterized in that: The invention comprises a prefabricated module, an anchoring module and an insulation module. The anchoring module is installed inside the furnace shell of the rotary kiln. The anchoring module comprises an anchoring net and anchoring bars. One end of the anchoring bar is fixed on the anchoring bar. The insulation module is close to the inner side of the furnace shell and is embedded in the grids of the anchoring net. 6 to 10 prefabricated modules are installed in the annular part of the rotary kiln. The prefabricated modules are provided with reserved holes corresponding to the anchoring bars. The reserved holes and the gaps between the prefabricated modules are filled with castables.

2. The ferronickel rotary kiln lining structure according to claim 1, characterized in that: A gap of 10-40 mm is provided between the prefabricated modules.

3. The ferronickel rotary kiln lining structure according to claim 1, characterized in that: The anchoring parts used in the anchoring module include three types: straight ribs, arc ribs and anchoring ribs. The anchoring parts are made of stainless steel and have a diameter of 10-12 mm.

4. The ferronickel rotary kiln lining structure according to claim 3, characterized in that: The straight ribs and arcuate ribs are welded to form a horizontally and vertically staggered anchoring net, the anchoring net is fixed on the furnace shell by spot welding, and the anchoring ribs are connected to the arcuate ribs of the welded anchoring net by screw holes or welding.

5. The ferronickel rotary kiln lining structure according to any one of claims 3 or 4, characterized in that: The surface of the anchor bar is coated with asphalt, and a 2-4 mm thick expansion cap is installed on the top or a tape of corresponding thickness is wrapped around it.

6. The ferronickel rotary kiln lining structure according to claim 1, characterized in that: When installing the insulation module, it is necessary to avoid the anchoring ribs of the anchoring module. The insulation module is made of a 10-20mm thick arc-shaped nano insulation board and a 40-60mm thick fiber insulation board bonded by high-temperature glue. The nano insulation board is located between the furnace shell and the fiber insulation board.

7. The ferronickel rotary kiln lining structure according to claim 1, characterized in that: The prefabricated module is made of a steel mold, and the prefabricated module is baked at 350-650° C. after demoulding and curing for 2-5 days.

8. The ferronickel rotary kiln lining structure according to claim 1, characterized in that: The casting material and the prefabricated component module are made of the same material.

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