Section type baking integrated shaft furnace and process for high-humidity non-metal tailing pellets

Abstract

The invention discloses a section type baking integrated shaft furnace and process for high-humidity non-metal tailing pellets. The section type baking integrated shaft furnace and process for the high-humidity non-metal tailing pellets can particularly solve the problems that the high-humidity pellets are prone to bursting, and finished pellets are unstable in quality, low in grade, high in production energy consumption and low in production efficiency when a traditional production method is adopted for the tailing pellets. The device is particularly suitable for drying, roasting and cooling of high-humidity non-metal tailing pellets and production of metallurgical pellets and small-particle lime, the purpose that one furnace has multiple purposes is achieved, the mode of drying, roasting, heat exchange and cooling and the mode of three in one are adopted, three-section type integrated production is achieved, and equipment investment, occupied space and comprehensive energy consumption are greatly reduced; the whole device is simple and clear in structure, high in production efficiency, high in yield and good in economical efficiency, and particularly has important significance in the aspects of recycling various powdery and muddy tailings, improving the production process level of the whole tailings pellets, reducing the production cost, greatly improving the grade and quality of products, reducing pollution and carbon, improving the ecological environment and the like.

Description

Technical Field

[0001] This application relates to the technical fields of non-metallic materials and tailings pellet production, and particularly relates to a shaft furnace and process for drying and roasting high-moisture tailings pellets such as phosphate ore, metallurgical pellets, and small-particle lime production. Background Art

[0006] In flotation production, the tailings produced usually exist in the form of pulp. Usually, production enterprises build tailings ponds to collect the tailings pulp, and then use dehydration and dry discharge processes (such as pressure filtration, etc.) to remove part of the water in the tailings pulp, forming tailings mud powder and mud cakes with a moisture content of about 35% for discharge.

[0007] Using fine-grained tailings powder, tailings pulp, and the mud cakes obtained after pressure filtration to prepare artificial lump ores such as sintered blocks and pellets and other solid materials and then using them for extracting high-value materials has become a new approach. However, in the further processing process, further dehydration, compression, and drying are required before further artificial lump making, roasting, etc.

[0008] Taking the phosphate ore smelting process as an example: Currently, the process for preparing yellow phosphorus from phosphate ore mainly uses the electric furnace method (thermal process for phosphorus production): putting natural phosphate ore lumps and reducing agents together in an electric furnace (mineral thermal furnace) and heating to 1300 - 1500°C for production. However, this process has high requirements for phosphate ore raw materials. Generally, it is required that the phosphate ore fed into the furnace has uniform particle size, generally 4 - 30mm. Too small particle size or too much fine powder will cause various problems. Therefore, the same process requirements apply to the solid formed products of phosphate ore powder: (1) The moisture and carbonate content should be low, generally the moisture should be below 2%; (2) The content of P2O5 should be higher than 20%, and it should have a certain thermal strength; (3) The particle size of the pellets or solid materials should be in the range of 20 - 50mm; (4) It should have a certain thermal strength, good thermal properties, and anti-crushing strength, and the pulverization rate should be low.

[0009] For the phosphate ore mud powder and mud cakes treated by the existing dehydration technology, the moisture content can only be controlled at about 30%. By mixing dry powder materials, the moisture can only be controlled above 15%. There is still a large gap from the requirement of traditional metallurgical pellet making with a moisture control of 7 - 8%. As a result, the phosphate ore pellets have high moisture, poor green pellet strength, are easy to pulverize, and have an extremely high return ore rate. Therefore, due to the high humidity of the pellets, traditional small circular shaft kilns and indigenous sintering and lump making methods cannot directly achieve in-furnace roasting. Additional drying and drying facilities need to be supported. Then, the pellets are taken out of the furnace for secondary transfer and enter the heat treatment furnace for sintering, and then taken out of the furnace for the third transfer to the cooling system.

[0010] When heat-treating phosphate ore green pellets, existing heat treatment technologies used in other similar fields are sometimes applied, such as the grate-kiln system. Some use muffle furnace roasting, which has high power consumption and cannot achieve large-scale production. Therefore, although directly applying existing heat treatment equipment from other industries can obtain finished phosphate ore pellets that meet the furnace charging requirements to a certain extent, there are inevitably key problems such as poor adaptability, high energy consumption, and unstable product quality.

[0011] In production practice, it is found that phosphate ore tailings are mainly composed of minerals such as calcium and magnesium carbonates. Dolomite is the main mineral component, followed by apatite. In addition, there are small amounts of quartz and calcite. The apatite is fluorapatite, which also exists in the form of a single mineral and is the main mineral containing phosphorus. The ore contains more than 20% CO2; it is very similar to the limestone used in existing lime calcination and has the same process characteristics as limestone decomposition to produce lime.

[0012] At the same time, there are also mature concepts that can be borrowed in the pellet production technology of the metallurgical industry. For example, the traditional rectangular pellet shaft furnace and the traveling grate are advanced roasting equipment and are gradually being widely used. Both have many advantages, showing unique advantages in pellet production. First of all, the rectangular shaft furnace has characteristics such as low investment, small floor area, simple operation, strong raw material adaptability, and fuel adaptability. However, due to the discharge temperature of the pellets produced by the shaft furnace body being as high as over 600 °C, there is a large heat energy loss, resulting in relatively high comprehensive energy consumption. In addition, facilities such as cooler and annular cooler with large investment need to be built separately. At the same time, different from metallurgical pellets with high strength and low pulverization rate, non-metallic tailings pellets have poor strength and high pulverization rate. Using methods such as "gas-solid" cooling and heat exchange of cooler and annular cooler (i.e., forced air cooling with an external secondary air source) cannot effectively achieve the purpose of cooling and heat exchange. The main problems are large cooling ventilation resistance, poor ventilation effect, and increased pulverization rate.

[0013] The traveling grate can ensure that the pellets obtain appropriate temperature, atmosphere, and time conditions at different stages, thus effectively improving the quality and performance of the pellets and meeting the requirements of large-scale production. The disadvantage is that the process is complex and the investment is large.

[0014] In the current phosphate ore pellet production process, the environmental protection treatment cost is high. For example, in the same container (furnace or kiln), drying, roasting, cooling, etc. are directly carried out, and the drying exhaust gas, combustion flue gas, and cooling exhaust gas are all mixed and discharged outside the container, resulting in a large volume of gas, complex composition, and difficult temperature control. The investment in environmental governance equipment is large.

[0015] How to integrate the drying process with the key technologies of rectangular pellet shaft furnaces and lime kiln shaft furnaces, and design a brand-new multi-functional integrated process and equipment suitable for the production of tailing pellets, metallurgical pellets, and small-particle lime by combining the advanced thermal engineering principles of roasting machines and the process characteristics of "solid-solid" heat exchange technology, so as to achieve the purpose of low investment, low energy consumption, and high output of tailing pellets, is particularly important. Summary of the Invention

[0016] Therefore, the present application provides a sectional roasting integrated shaft furnace and process for high-moisture non-metallic tailing pellets, which can particularly solve the problems of easy explosion of high-moisture pellets, unstable quality of finished pellets, low grade, high pulverization rate, high production energy consumption, inability to treat harmful waste gas, and low production efficiency existing in the traditional production method of tailing pellets.

[0017] In order to achieve the above object, the present application provides the following technical solutions:

[0018] In a first aspect, a sectional roasting integrated shaft furnace for high-moisture non-metallic tailing pellets includes a vertical furnace body, and the vertical furnace body is a three-section structure of upper, middle, and lower parts. The upper part is a drying section, the middle part is a roasting section, and the lower part is a heat exchange and cooling section;

[0019] The inlet end of the drying section is connected to a feeding conveyor by a high-low double-track reciprocating shuttle car, and a multi-stage vibrating feeding type drying bed device is arranged below the feeding point of the high-low double-track reciprocating shuttle car inside the drying section. A powder collecting bin one is arranged below the vibrating feeding type drying bed device;

[0020] An intermediate partition is arranged between the roasting section and the drying section. An in-furnace circulating air channel communicating with the powder collecting bin one is longitudinally arranged at the central position inside the roasting section. Two roasting areas are formed on both sides of the in-furnace circulating air channel, and a connecting rod type double-layer air lock and sealing valve device for connecting the roasting section and the drying section is arranged above each roasting area. A drying primary air outlet is arranged above the in-furnace circulating air channel for heating and supplying air to the vibrating feeding type drying bed device; Two combustion chambers are symmetrically arranged on both sides of the roasting section furnace body; An out-of-furnace circulating air channel is arranged at the bottom of the in-furnace circulating air channel, and the out-of-furnace circulating air channel is connected to a powder collecting bin two;

[0021] A toothed crushing and discharging device is arranged between the heat exchange and cooling section and the roasting section. A vibrating ash discharger is arranged at the bottom of the heat exchange and cooling section, and the heat exchange and cooling section is provided with a cooling air inlet and is connected with a hot air rising pipe one and a hot air rising pipe two. The hot air rising pipe one is communicated with the combustion chamber, and the hot air rising pipe two is communicated with the out-of-furnace circulating air channel.

[0022] Second aspect, a process for a sectional baking integrated shaft furnace for high-moisture non-metallic tailings pellets, using the above-mentioned sectional baking integrated shaft furnace for high-moisture non-metallic tailings pellets, the process comprising the following steps:

[0023] The wet pellets from the pelletizing or briquetting production system are conveyed by a feeding conveyor to the upper part of a high-low double-track reciprocating shuttle car. The pellets enter the drying section through the high-low double-track reciprocating shuttle car for uniform reciprocating feeding. The wet pellets are gradually dried to the lowest moisture content through step-by-step drying by a multi-stage vibrating feeding type drying bed device, completing the entire drying process of the wet pellets.

[0024] The pellets dried in the drying section enter the roasting section through a connecting rod type double-layer air-lock sealing valve device. During the descent in the roasting section, the pellets exchange heat and are roasted with the hot flames blown by several fire ports longitudinally arranged in the cross-section of the drying section.

[0025] The roasted pellets gradually and slowly descend into the internal part of a toothed crushing and discharging device. The pellets are discharged into the heat exchange and cooling section through the rotation and crushing of the toothed crushing and discharging device. Heat exchange is carried out in the heat exchange and cooling section to convert the waste heat of the high-temperature pellets into high-temperature air. Part of the high-temperature air after heat exchange enters the combustion chamber for combustion air assistance, and the other part of the high-temperature air enters the drying section for material drying. After the heat exchange work is completed, the finished pellets are discharged by a vibrating ash discharger to complete the pellet discharging work and enter the downstream process.

[0026] Compared with the prior art, the present application has at least the following beneficial effects:

[0027] (1) The furnace type structure of this sectional baking integrated shaft furnace is set as a three-section baking and heat exchange integration, adopting a "drying + roasting + heat exchange and cooling", "three-in-one" mode to achieve three-section integrated production, greatly reducing equipment investment and floor area, and also reducing the comprehensive energy consumption; the device structure is simple and compact, with high production efficiency, improved and stable product quality, and good economy, especially suitable for the drying, roasting and cooling of high-moisture pellets of non-metallic ore tailings, as well as the production of metallurgical pellets and small particle lime.

[0028] (2) Compared with metallurgical pellets, the key problem of tailings pellets is poor strength. Setting the drying section and the roasting section as an integration solves the problems of high pellet breakage rate and high return ore amount caused by the traditional process due to the independent drying system and independent roasting system in the secondary transfer, secondary furnace charging and transportation of pellets.

[0029] (3) The integrated drying and roasting device is set as a smoke-blocking connected structure. The production time of the drying section and the roasting time can be produced synchronously or asynchronously according to the material quantity. The drying section time can be effectively increased and adjusted according to the moisture content of the wet pellets. Since the drying time, temperature and output are adjustable, the problems of high-humidity pellets that cannot be directly put into the furnace and the serious cracking of raw balls in the traditional process are solved, the return rate of the finished pellets is greatly reduced, the finished product rate of the finished pellets is effectively improved, and the energy consumption is reduced.

[0030] (4) Since the roasting section is set up for independent roasting and independent unloading, the roasting time can be greatly shortened and adjusted. In addition, since the finished pellet ore is discharged by a combination of toothed roller unloading in the furnace and vibrating feeder discharge outside the furnace, rapid discharge can be achieved, solving the problems of long roasting time, easy sticking of materials, and inability to discharge suspended materials and lumps in the traditional process.

[0031] (5) The roasting section combustion chamber adopts a variety of energy structure application modes, which can make the range of energy varieties and cost selection more extensive, and also avoid the constraints and risks of external single energy.

[0032] (6) The drying flue gas (water vapor) and the roasting flue gas are discharged independently, so that the flue gas after drying only needs to be dusted, and no harmful elements need to be removed. Moreover, the harmless flue gas volume accounts for 70-80% of the total flue gas volume. The harmful flue gas volume in the roasting section only accounts for 20-30% of the total flue gas volume, which greatly reduces the equipment investment for the treatment of harmful gases in the flue gas.

[0033] (7) Due to the independent operation of the roasting section and the substantial reduction of harmful gases, the cost of carbon dioxide gas treatment equipment and operating costs are greatly reduced, which can achieve a low-cost carbon dioxide emission reduction effect. For every 100,000 tons of phosphate tailings processed, the emission reduction (equivalent to carbon dioxide) can be about 15,000 tons.

[0034] (8) It realizes the multifunctionality of one furnace, retains the characteristics and process properties of the original traditional rectangular pelletizing shaft furnace, and can calcine metallurgical pellets, not limited to the oxidation roasting and reduction roasting of magnetite, hematite, limonite and other pellets; it also has the function of independently producing metallurgical pellets and lime production, realizing the purpose of "one furnace for multiple uses".

[0035] (9) Since the chemical composition of most non-metallic minerals and phosphate tailings, such as CaO, MgO, and CO2, is very similar to that of limestone, the process of producing lime can be realized, especially the production of lime using small-particle stones of 5-20 mm.

[0036] (10) High output. Compared with the circular pelletizing vertical furnace with the same roasting area, the output production coefficient is 4 to 5 times.

[0037] (11) Low investment. Compared with a belt grate kiln with the same output, its investment is only about 10% of that of the belt grate kiln, with extremely high investment cost performance.

[0038] (12) During the roasting process, a large amount of carbon dioxide (CO2) gas is decomposed and discharged, significantly improving the grade of the roasted tailings pellets. The grade is at least 20% higher than that of the original ore lump directly fed into the electric furnace, significantly improving the economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] To more intuitively illustrate the prior art and this application, exemplary drawings are given below. It should be understood that the specific shapes and structures shown in the drawings generally should not be regarded as limiting conditions when implementing this application; for example, those skilled in the art are capable of making routine adjustments or further optimizations to the addition / removal / attribution division of certain units (components), specific shapes, positional relationships, connection methods, dimensional proportional relationships, etc. based on the technical concept disclosed in this application and the exemplary drawings.

[0040] Figure 1 Structural schematic of a sectional roasting integrated shaft furnace for high-moisture non-metallic tailings pellets provided by an embodiment of this application Figure 1 ;

[0041] Figure 2 Structural schematic of a sectional roasting integrated shaft furnace for high-moisture non-metallic tailings pellets provided by an embodiment of this application Figure 2 ;

[0042] Figure 3 For Figure 1 Schematic diagram of the material flow distribution shown;

[0043] Figure 4 For Figure 1 Schematic diagram of the flow direction of the cooling heat exchange air and the drying air shown;

[0044] Figure 5 For Figure 1 Schematic diagram of the flow direction of the combustion flame high-temperature gas flow and the high-temperature waste gas shown;

[0045] Figure 6 For Figure 1 Schematic diagram of the material collection flow direction of the out-of-furnace circulation channel and the powder collection bin II shown;

[0046] Figure 7 For Figure 1 Structural schematic of the middle connecting rod type double-layer air-lock seal valve device;

[0047] Figure 8 For Figure 1 Schematic diagram of the air inlet position of the high-temperature waste gas waste heat exchange device and the sealed gas collection box shown;

[0048] Figure 9 For Figure 1 Schematic diagrams of the gas inlets and outlets of the medium- and high-temperature waste heat heat exchange device;

[0049] Figure 10 For Figure 1 Schematic diagram of the structure of the medium-tooth-shaped crushing and discharging device;

[0050] Figure 11 For Figure 1 Schematic diagram of the structure of the medium steam reforming device;

[0051] Figure 12 For Figure 1 Schematic diagram of the structure of the medium steam collection device.

[0052] Explanation of reference numerals:

[0053] 1. Drying section; 1-1. Feeding conveyor; 1-2. High-low double-rail reciprocating shuttle-type cloth-feeding vehicle; 1-2-1. Guide chute for the cloth-feeding vehicle; 1-3. Vibration feeding type drying bed device; 1-3-1. Drying bed vibration device; 1-4. Anti-over-wetting device; 1-5. Dehumidifying fan; 1-6. Pipe 1; 1-7. Pipe 2; 1-8. Valve 1; 1-9. Link-type double-layer air-lock sealing valve device; 1-9-1. Upper valve body; 1-9-2. Lower valve body; 1-9-3. Hydraulic cylinder; 1-9-4. Link; 1-10. Drying primary air outlet 1; 1-11. Drying primary air outlet 2; 1-12. Drying secondary air pipe; 1-13. Drying secondary air pipe valve; 1-14. Sealed gas collection box; 1-15. Dust removal main pipe for the drying section; 1-16. Powder screening device; 1-17. Powder collection bin 1; 1-18. Intermediate partition; 1-19. Oblique air outlet; 1-20. Medium- and high-temperature waste heat heat exchange device; 1-20-1. High-temperature waste gas inlet; 1-20-2. Cold air conditioning inlet; 1-20-3. High-temperature air outlet; 1-21. Total exhaust pipe for the waste gas after heat exchange; 1-22. Steam reforming device; 1-22-1. Steam collection device; 1-22-2. Steam drum; 1-22-3. Condensate drum; 1-22-4. Steam outlet; 1-22-5. Condensate downcomer;

[0054] 2. Roasting section; 2-1 Combustion chamber; 2-1-1 Peephole; 2-2 Gas fuel burner; 2-2-1 Primary combustion air duct; 2-2-2 Gas pipeline; 2-3 Solid fuel burner; 2-3-1 Solid fuel conveying pipeline; 2-4 Ash hopper; 2-4-1 Sonic soot blower; 2-5 Valve II; 2-6 Ash chute; 2-7 In-furnace circulating air channel; 2-8 Out-of-furnace circulating air channel; 2-8-1 Powder collection bin II; 2-8-2 Release valve; 2-8-3 Powder dropping pipeline; 2-8-4 Powder collection tank; 2-9 Toothed crushing discharger;

[0055] 3. Heat exchange and cooling section; 2-10 High-temperature solid-solid heat exchange device; 2-10-1 Combustion air inlet; 2-10-2 External circulation pipeline I; 2-10-3 Hot air rising pipeline I; 2-10-4 Valve III; 2-11 Medium-temperature solid-solid heat exchange device; 2-12 Low-temperature solid-solid heat exchange device; 2-12-1 Cooling air inlet; 2-12-2 Hot air outlet I; 2-12-3 External circulation pipeline II; 2-12-4 Hot air outlet II; 2-12-5 Hot air rising pipeline II; 2-13 Vibrating ash discharger; 2-14 Secondary combustion air duct; 2-15 Secondary air mixing duct; 2-15-1 Regulation valve; 2-16 Combustion air blower; 2-17 Cooling air blower. Detailed implementation mode

[0056] The following further details the present application through specific embodiments in conjunction with the accompanying drawings.

[0057] In the description of the present application: Unless otherwise specified, "a plurality" means two or more. Terms such as "first", "second", "third", etc. in the present application are intended to distinguish the objects being referred to, and do not have special significance in terms of technical connotations (for example, they should not be understood as emphasizing importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0058] Terms such as "upper", "lower", "left", "right", "middle", etc. cited in the present application are generally indications of the general relative position relationship for the convenience of intuitively understanding in conjunction with the accompanying drawings, and do not absolutely limit the position relationship in the actual product.

[0059] Based on the problems existing in the background technology, and the lack of special drying and heat treatment equipment for powder ore pellets, resulting in unstable quality of the finished pellet products, high production energy consumption, low production efficiency, etc., the purpose of the present application is to provide an application technology for the high-value recovery of industrial tailings, which is particularly suitable for the drying, roasting and cooling of high-moisture pellets of non-metallic ore tailings, as well as the production of metallurgical pellets and small-particle lime.

[0060] This application uses pellets (pelletizing or briquetting) made from various types of tailings powder ore and high-moisture tailings mud with the above typical characteristics for drying, roasting, heat exchange, and cooling to produce pellet products required downstream. Taking the technology of producing low-grade yellow phosphorus pellet ore from yellow phosphorus tailings as an implementation case, the produced sintered pellet ore fully meets the requirements of particle size and strength for phosphorus production in production processes such as electric furnaces. Moreover, during the roasting process, the low-grade phosphate rock is enriched, effectively improving the product grade, removing substances such as carbon dioxide and organic matter that are unfavorable for yellow phosphorus production, and enriching substances such as phosphorus pentoxide (phosphate rock grade) and silicon dioxide in the phosphate rock that are beneficial for yellow phosphorus production, making the yellow phosphorus production process more low-carbon, more environmentally friendly, and more energy-efficient, while achieving the purpose of comprehensive utilization of low-grade phosphate rock resources.

[0061] The baking integrated shaft furnace provided by this application is different from the traditional earth method sintering and the process of drying first and then sintering. It optimally combines the drying + sintering + cooling mode in the traditional process and adopts the "drying + roasting + heat exchange cooling", "three-in-one" mode to achieve three-stage integrated production, solving the process defects in the current traditional non-metallic ore powder briquetting. In particular, it organically combines the new drying technology for high-moisture high-humidity pellets with the production process principle of lime kilns and the structural characteristics of traditional metallurgical pellet shaft furnaces, not only achieving the purpose of drying high-moisture pellets without external energy (waste gas waste heat utilization), but also achieving the purpose of independent emission of drying waste gas (water vapor), roasting combustion harmful waste gas, and blast cooling waste gas, and also having the function of independently producing metallurgical pellets and lime production, achieving the purpose of "one furnace with multiple uses".

[0062] At the same time, the technical structure of this application is simple, practical, and compact, with high production efficiency, high output, and good economy. In particular, it is of great significance for the recycling application of various powdery and muddy tailings, improving the overall tailings pellet production process level, reducing production costs, improving product grade and quality, increasing economic benefits, and in aspects such as pollution reduction and carbon reduction and improving the ecological environment.

[0063] The process technical means and measures adopted in this application are as follows:

[0064] I. Key process mechanisms and measures adopted:

[0065] (1). Adopt an integrated three-stage connected structure of drying, roasting, and cooling. The furnace body is in a vertical structure. The upper section is the drying (drying) section, the middle section is the roasting section, and the lower section is the cooling heat exchange section.

[0066] (2). The materials entering the furnace are round pellets produced by a pelletizing machine, oval pellets produced by a briquetting machine, and other round, cylindrical and other granular materials produced by other methods.

[0067] (3) The joint between the drying section and the roasting section of the furnace body adopts the latest air-lock sealing technology. The drying system and the roasting system are each set in an independent sealed structure. The air-lock sealing technology uses multi-point feeding. The control valve at the feeding point adopts a double-link multi-point synchronous transmission structure. The upper and lower control valves are opened and closed in a staggered manner to achieve air-lock sealing and non-pressure feeding, that is, the flue gases of the drying section and the roasting section do not communicate during the feeding process.

[0068] (4) The drying section is only related to the feeding system, and its working process has no direct connection with the roasting section and can be operated independently. Its flue gas is also independently discharged under negative pressure. All are the flue gases after the heat exchange between the waste heat flue gases in the cooling and heat exchange section and the materials in the drying section (only water vapor and part of the dust). The flue gas after drying only needs dust removal and does not need to remove harmful elements. Moreover, the flue gas volume accounts for 70-80% of the total flue gas volume.

[0069] (5) The feeding of the drying section adopts a shuttle type distributor to evenly distribute the materials reciprocally in the furnace. Multiple layers (multiple stages) of drying beds are arranged inside the drying section. The surface of the drying bed adopts a "louver" structure to facilitate ventilation and drying. The drying bed body adopts a "variable frequency vibration" feeding method. The bed bodies at different levels are independent and have different vibration frequencies, which can achieve precise control of the feeding volume of a single bed body and prevent the materials from sticking to the bed surface. The angle of the drying bed surface is set as a movable adjustable structure and can be adjusted to an appropriate angle according to needs.

[0070] (6) According to the drying characteristics of the shaft furnace and the characteristics of high moisture and high humidity of phosphate ore pellets, an anti-over-wetting device is arranged at the lower part of the first zone of the drying bed. Through the mixing of cold air and hot air and local forced air supply adjustment, the temperature is adjusted and the moisture discharge speed is increased, effectively solving the problems of adhesion, agglomeration caused by over-wetting of the pellets and reducing the bursting of wet pellets. Reducing the bursting of green pellets and controlling the drying moisture are effective means to improve the pellet quality and reduce the return ore rate.

[0071] (7) In addition to retaining the vibration feeding function, the multi-stage drying bed structure in the drying section adds a screening function to the last-stage drying bed, so that the powder generated during the drying process falls into the in-furnace circulating air channel and the powder descending channel and directly goes outside the furnace, avoiding entering the roasting section. Reducing the powder entering the roasting section is an important means to solve the adhesion during the pellet roasting process and reduce the air flow resistance during the material roasting process.

[0072] (8) The furnace body of the roasting section adopts a "T"-type vertical closed structure, and the cross-section is a symmetric double-chamber rectangular structure. The combustion chamber is set as a circle or a rectangle. The roasting method is to supply heat through positive pressure double-chamber opposite spray nozzles. The "flame-retarded combustion technology" is used to generate high-temperature air (flue gas) for roasting pellets. The temperature adjustment is convenient and simple, solving the key problem that the traditional vertical kiln's "direct flame combustion of dozens of burners around the kiln body" method is easy to melt and bond the surface of the pellets.

[0073] (9) The combustion chamber is set for a multi-fuel combustion process. The fuels can include yellow phosphorus tail gas and other industrial tail gases (such as blast furnace gas, coke oven gas, producer gas), as well as gaseous fuels such as biomass gas and natural gas. The combustion chamber is specially arranged with a double-layer burner process. An ash collection bin and a transfer channel are set at the lower part of the combustion chamber, enabling automatic ash discharge and transfer for the combustion of solid fuels such as coal injection and biomass powder injection, as well as combustion ash.

[0074] (10) The roasting section of the furnace body has positive-pressure independent external exhaust of flue gas, and the flue gas volume only accounts for the range of 20 - 30% of the total flue gas volume, greatly reducing the equipment investment for treating harmful flue gas components.

[0075] (11) Inside the roasting section, a channel-type in-furnace circulating air channel device is set in the longitudinal middle part of the calcination zone. The waste heat energy of the materials inside the roasting section and after ore discharge is converted into hot air and then introduced (by the pressure reduction method) into the external circulating air channel inside, and then enters the drying section for drying production. The drying heat energy of the drying section all comes from the heat energy after heat exchange in the cooling zone.

[0076] (12) The in-furnace circulating air channel device is provided with a screening and powder collection device at the connection between the flue gas outlet and the drying bed of the drying section, collecting and dropping the powders generated during the drying process (by the gravity method) into the inside of the in-furnace circulating air device. During the downward process of the dust in the in-furnace circulating air channel device, it conducts sufficient heat exchange with the upward air flow inside the in-furnace circulating air device, forming a "suspension type" roasting, which can quickly complete the roasting process. The roasted powders directly enter the external powder collection bin.

[0077] (13) An external circulating air channel device is set to achieve the function of collecting waste heat energy outside the furnace, fully recovering the waste heat energy during the heat exchange process of the materials in the cooling section, and achieving the purpose of energy conservation.

[0078] (14) A pipeline-type waste heat exchange device is set to exchange heat between the waste heat flue gas (400 - 500 degrees) independently discharged from the roasting section and the incoming air of the drying section, achieving the purpose of waste heat utilization and energy conservation, and enabling the adjustable temperature of the flue gas in the drying section (70 - 400 degrees);

[0079] (15) The entire heat exchange and cooling section adopts a "three-stage solid-solid heat exchanger" to conduct solid-solid heat exchange on the finished pellet ore entering the ore discharge section from the roasting section. The hot air after heat exchange enters the combustion burner in the combustion chamber for combustion support and enters the drying system for heat energy utilization; the heat exchange air does not directly contact the materials and only flows in the fixed channels in the heat exchanger, and contacts and exchanges heat with the materials through a special heat conduction structure and materials, achieving the solid-solid heat exchange between the solid heat conduction parts and the solid materials (pellets).

[0080] (16) The "three sections" of the furnace body can all achieve independent production. For example, independent drying can be carried out, independent roasting production can be carried out, and independent cooling and heat exchange can be carried out. In particular, the "three-stage solid-solid heat exchanger" in the cooling section adopts a combined and modular structure, and each stage of the heat exchanger can be used independently. Moreover, when the hot ore discharging method is used for production, the cooling ventilation system can be closed to achieve hot ore discharging.

[0081] (17) A steam recovery device is set in the drying system to recover all the generated steam for production, which not only solves the problem of rapid moisture discharge, but also solves the problem that the high-humidity moisture in the dust removal system cannot be effectively removed and the problem of "white smoke (water vapor)" in the chimney discharge during the dust removal and atmospheric emission.

[0082] II. Key equipment and measures adopted:

[0083] (1) Feeding device

[0084] A high-low double-rail reciprocating shuttle-type feeding vehicle is adopted. The walking guide rail outside the furnace body is combined with the guiding rail inside the furnace. The guiding walking wheels set at the head of the feeder and the guiding slideway set inside the furnace form a reciprocating running mechanism for orientation and positioning, making the feeding vehicle run smoothly, with uniform and loose material discharging, and the pellets are not easy to break and adhere.

[0085] (2) Vibration feeding type drying bed device

[0086] The drying bed is arranged vertically in multiple stages, and each stage structure adopts a combination method of a "positive umbrella shape" and an "inverted umbrella shape". The "positive umbrella-shaped" bed body receives materials outside the outer wall of the bed surface, and the "inverted umbrella-shaped" bed body receives materials inside the inner wall of the bed surface. The bed surface adopts a transverse louver structure, enhancing the flow rate and velocity of the transverse air flow, making the materials heated more evenly. Each drying bed is provided with a frequency modulation vibration device to adjust the vibration frequency according to the feeding amount of each bed body, and independently adjust the heating time of the materials; the bed surface of each drying bed is of a movable angle-adjustable structure, and the angle can be adjusted within a certain range.

[0087] (3) Gravity screening device

[0088] A gravity screening device is set at the lower part of the drying bed to carry out sliding screening through the gravity factor of the materials and the particle size relationship of the materials, reducing and controlling the small-particle materials passing through the screen from entering the calcination section of the furnace body;

[0089] (4) Anti-overwetting device

[0090] An anti-overwetting device is set at the lower part of the first feeding layer of the drying bed. Through the air supply of a special fan for air mixing and air distribution, the diffusion and flow velocity of the moisture are increased, avoiding the problem of secondary adhesion of the materials and reducing the factors of pellet explosion.

[0091] (5) Link-type double-layer air-lock seal valve device

[0092] This device is the key device for realizing air-lock sealing and non-pressure blanking. Through the upper and lower two-stage connecting rods, the valve stems of multiple groups of valves perform reciprocating motion in opposite directions, realizing the alternating blanking of the upper and lower two-layer valve bodies, achieving the function of air-lock sealing blanking, and ensuring that the flue gas in the calcination section of the furnace cannot enter the drying section;

[0093] (6), High-temperature waste gas waste heat heat exchange device

[0094] This device is the key device for realizing the conversion of waste heat energy of flue gas in the roasting section to the drying section. This device exchanges the heat energy of the high-temperature flue gas generated in the calcination section with the normal-temperature air outside the furnace. By adjusting the air intake in the device, the temperature of the output hot air can be adjusted. The output hot air enters the drying section for drying, achieving the effects of flue gas temperature adjustment and air mixing, making the drying effect better; moreover, the high-temperature air after heat exchange directly enters the combustion chamber of the roasting section for heat supply and combustion support, increasing the combustion chamber temperature by at least more than 200 °C, that is, improving the roasting temperature and achieving the purpose of energy saving.

[0095] (7), Tooth-shaped crushing and discharging device

[0096] This device is the dividing line between the roasting section and the cooling and heat exchange section, and is the key device for realizing discharging and material discharging distribution. Each blanking (ore discharging) channel is provided with an independent rotating tooth-shaped crushing and discharging device. Through the rotation of the tooth-shaped structure, discharging and crushing are completed, and single-point and multi-point synchronous discharging are achieved.

[0097] (8), Ore discharging heat exchange device

[0098] Adopt a brand-new "three-stage solid-solid heat exchange" device. This device conducts "solid-solid" waste heat exchange between the combustion-supporting air, the cooling air, and the finished pellet materials in the ore discharging section, achieving the dual purposes of increasing the temperature of the combustion-supporting air and reducing the temperature of the materials for cooling.

[0099] (9), Steam conversion device and steam collection device

[0100] Adopt the combined application method of the steam collection device and the steam conversion device. Through the two-stage steam drum device set, all the steam in the drying system is recycled and utilized.

[0101] The following combines the drawings with specific embodiments to elaborate in detail on the structure and main production process route of the technical solution provided by this application.

[0102] The technical process of this technology is divided into two main production process routes. Route 1: Independently drying and roasting high-moisture tailings pellets; Route 2: Independently roasting metallurgical pellets and lime.

[0103] Example 1 (Route 1)

[0104] SeeFigures 1 - 12 , a sectional baking integrated shaft furnace for high-moisture non-metallic tailings pellets, includes a vertical furnace body. The vertical furnace body is a three-section structure of upper, middle and lower parts. The upper part is a drying section 1 (drying section), the middle part is a roasting section 2, and the lower part is a heat exchange and cooling section 3. When producing high-moisture non-metallic tailings pellets, when using the pelletizing method, the particle size of the material is preferably 8 - 20 mm, and when using the briquetting method, the particle size of the material is preferably 20 - 40 mm.

[0105] The inlet end of the drying section 1 is connected to the feeding conveyor 1-1 through a high-low double-track reciprocating shuttle car 1-2. Inside the drying section 1, a multi-stage vibrating feeding drying bed device 1-3 is arranged below the feeding point corresponding to the double-track reciprocating shuttle car 1-2. A powder screening device 1-16 and a first powder collection bin 1-17 connected to the powder screening device 1-16 are arranged below the vibrating feeding drying bed device 1-3.

[0106] An intermediate partition 1-18 is arranged between the roasting section 2 and the drying section 1. The drying section 2 is composed of a sealed air collection box body 1-14 made of steel structure. A furnace internal circulation air channel 2-7 is longitudinally arranged at the central position inside the roasting section 2. Two roasting areas with the same capacity and synchronous operation are formed on both sides of the furnace internal circulation air channel 2-7. And a connecting rod type double-layer air lock and sealing valve device 1-9 for connecting the roasting section 2 and the drying section 1 is arranged above each roasting area. A first drying primary air outlet 1-10 and a second drying primary air outlet 1-11 are arranged above the furnace internal circulation air channel 2-7, which are used to supply heat and air to the vibrating feeding drying bed device 1-3. Two combustion chambers 2-1 are symmetrically arranged on both sides of the roasting section furnace body. An external furnace circulation air channel 2-8 is arranged outside the roasting section 2 corresponding to the bottom of the furnace internal circulation air channel 2-7. The external furnace circulation air channel 2-8 is connected to a second powder collection bin 2-8-1.

[0107] A toothed crushing and discharging device 2-9 is arranged between the heat exchange and cooling section 3 and the roasting section 2. A cooling air inlet 2-12-1, a first hot air rising pipe 2-10-3 and a second hot air rising pipe 2-12-5 are arranged on the heat exchange and cooling section 3. The first hot air rising pipe 2-10-3 is connected to the combustion chamber 2-1, and the second hot air rising pipe 2-12-5 is connected to the external furnace circulation air channel 2-8. A vibrating ash discharger 2-13 is arranged at the bottom of the heat exchange and cooling section 3.

[0108] Preferably, a three-stage solid-solid heat exchanger is adopted in the heat exchange and cooling section, which is divided into a high-temperature solid-solid heat exchange device 2-10, a medium-temperature solid-solid heat exchange device 2-11, and a low-temperature solid-solid heat exchange device 2-12 arranged from top to bottom. The outlet of the toothed crushing and discharging device 2-9 is connected to the high-temperature solid-solid heat exchange device 2-10. The high-temperature solid-solid heat exchange device 2-10 is provided with a combustion-supporting air inlet 2-10-1 and a second hot air outlet 2-12-4. And multiple groups of external circulation pipelines 2-10-2 are arranged outside the high-temperature solid-solid heat exchange device 2-10. The multiple groups of external circulation pipelines 2-10-2 are connected to the combustion chamber 2-1 (specifically, the gas fuel burner 2-2) through a hot air rising pipeline 2-10-3. The second hot air outlet 2-12-4 is communicated with the out-of-furnace circulating air channel 2-8 through a hot air rising pipeline 2-12-5. The hot air rising pipeline 2-12-5 is also connected to a secondary air mixing pipeline 2-15. A regulating valve 2-15-1 is arranged on the secondary air mixing pipeline 2-15. The combustion-supporting air inlet 2-10-1 is connected to a combustion-supporting fan 2-16. A secondary combustion-supporting air pipeline 2-14 is also arranged at the bottom of the furnace body of the roasting section below the combustion chamber 2-1.

[0109] The low-temperature solid-solid heat exchange device 2-12 is provided with a cooling air inlet 2-12-1 and a first hot air outlet 2-12-2. The first hot air outlet 2-12-2 is communicated with the medium-temperature solid-solid heat exchange device 2-11 through an external circulation pipeline 2-12-3. The cooling air inlet 2-12-1 is connected to a cooling fan 2-17. A vibrating ash discharger 2-13 is located at the bottom of the low-temperature solid-solid heat exchange device 2-12.

[0110] Preferably, referring to Figure 7 , the connecting rod type double-layer air-lock and seal valve device 1-9 includes an upper valve body 1-9-1 located in the upper part and a lower valve body 1-9-2 located in the lower part. The upper valve body 1-9-1 and the lower valve body 1-9-2 are connected to a hydraulic cylinder 1-9-3 through a connecting rod 1-9-4. The upper valve body 1-9-1 is used to control the entry and preliminary air-lock of materials. The lower valve body 1-9-2 is used to control the discharge and further air-lock of materials. The hydraulic cylinder 1-9-3 serves as a driving device to provide power to open and close the valve body.

[0111] Further preferably, the connecting rod type double-layer air-lock and seal valve device 1-9 further includes an air-lock and seal assembly. The air-lock and seal assembly includes a multi-point feeding control valve. The multi-point feeding control valves are respectively installed on the upper valve body 1-9-1 and the lower valve body 1-9-2, and adopt a double-layer connecting rod type multi-point synchronous transmission structure. The upper and lower control valves are opened and closed in a staggered manner to achieve air-lock and seal and non-pressure feeding, that is, to prevent the flue gas in the drying section from communicating with that in the roasting section during the feeding process.

[0112] Preferably, referring to Figure 11 and Figure 12, there is a steam reforming device 1-22 outside the sealed gas collecting box 1-14, and a steam collecting device 1-22-1 connected to the steam reforming device is arranged inside the sealed gas collecting box 1-14. The steam reforming device 1-22 is connected to a condensate water packet 1-22-3 through a steam packet 1-22-2. A steam outlet 1-22-4 is arranged at the upper part of the steam packet 1-22-2, and a condensate water downward port 1-22-5 is arranged at the bottom of the condensate water packet 1-22-3.

[0113] Preferably, a drying section dust removal main pipe 1-15 is arranged at the top of the sealed gas collecting box 1-14, and a regulating valve is arranged on the drying section dust removal main pipe 1-15; an inclined air outlet 1-19 is arranged at the top of the roasting section furnace body, and the inclined air outlet 1-19 is connected to a high-temperature waste gas waste heat exchange device 1-20. A high-temperature waste gas inlet 1-20-1, a cold air regulating inlet 1-20-2 and a high-temperature air outlet 1-20-3 are arranged on the high-temperature waste gas waste heat exchange device 1-20. The high-temperature air outlet 1-20-3 is connected to a drying secondary air pipe 1-12. The high-temperature waste gas waste heat exchange device 1-20 is also connected to a flue gas dust removal system through a waste gas outlet main pipe 1-21 after heat exchange.

[0114] Further preferably, a moisture-proof device 1-4 is arranged above the vibrating feeding type drying bed device 1-3. The moisture-proof device 1-4 is connected to a dehumidifying fan 1-5 arranged outside the sealed gas collecting box 1-14 through a pipe 1-6, and the dehumidifying fan 1-5 is also connected to the high-temperature waste gas waste heat exchange device 1-20 through a pipe 1-7.

[0115] Preferably, the high-low double-track reciprocating shuttle type cloth feeder 1-2 includes a cloth feeder main body, an outside-furnace vehicle running guide rail and an inside-furnace guide rail. The outside-furnace vehicle running guide rail provides support and guidance for the movement of the cloth feeder main body; the outside-furnace vehicle running guide rail is combined with the inside-furnace guide rail. A cloth distributor is arranged at the front end of the cloth feeder main body, and a guiding running wheel is arranged at the head of the cloth distributor. The guiding running wheel and a cloth feeder guiding slideway 1-2-1 arranged inside the furnace form a reciprocating running mechanism for orientation and positioning, so that the cloth feeder main body runs smoothly, the feeding is uniform and loose, and the pellets are not easy to break and adhere; the material enters the cloth distributor from the feed inlet of the cloth feeder main body and is evenly distributed into the furnace through a plurality of feeding ports at the head of the cloth distributor.

[0116] Preferably, the vibrating feeding type drying bed device is arranged in a multi-stage vertical layout, and each stage structure is composed of a "positive umbrella shape" and an "inverted umbrella shape". The "positive umbrella shape" bed body receives materials outside the outer wall of the bed surface, and the "inverted umbrella shape" bed body receives materials inside the inner wall of the bed surface. The bed surface adopts a transverse louver structure.

[0117] Preferably, the furnace body of the roasting section adopts a "T"-shaped vertical closed structure, and the cross-section is a symmetric double-chamber rectangular structure; the combustion chamber is set as circular or rectangular, and the roasting method is positive-pressure double-chamber heating with opposite-facing spout openings.

[0118] Preferably, two gas fuel burners 2-2 and one solid fuel burner 2-3 are respectively arranged at the end faces of the two combustion chambers 2-1. The gas fuel burner 2-2 is connected to the first combustion air duct 2-2-1, and the solid fuel burner 2-3 is connected to the solid fuel conveying pipeline 2-3-1.

[0119] More preferably, a dust collecting hopper 2-4, an acoustic soot blower 2-4-1 and a dust collecting chute 2-6 connected to the dust collecting hopper 2-4 are arranged at the bottom of the combustion chamber 2-1. A second valve 2-5 is arranged on the dust collecting chute 2-6; the combustion chamber 2-1 also has a peephole 2-1-1.

[0120] Preferably, the second powder collecting bin 2-8-1 is connected to the powder collecting tank 2-8-4 through a powder dropping pipeline 2-8-3, and a release valve 2-8-2 is arranged at the lower part of the second powder collecting bin 2-8-1.

[0121] Based on the above-mentioned sectional baking integrated vertical furnace for high-moisture non-metallic tailing pellets, the present application also provides a process for the sectional baking integrated vertical furnace for high-moisture non-metallic tailing pellets, and the process is as follows:

[0122] When producing high-moisture non-metallic tailing pellets, when using the pelletizing method, the particle size of the material is preferably 8-20 mm, and when using the briquetting method, the particle size of the material is preferably 20-40 mm. The wet pellets produced by the pelletizing or briquetting production system are conveyed to the upper part of the high-low double-track reciprocating shuttle-type distributing car 1-2 through the feeding conveyor 1-1. The pellets enter the drying section 1 of the vertical furnace through the high-low double-track reciprocating shuttle-type distributing car 1-2 for uniform reciprocating distribution. Since the moisture content of the pellets is relatively high, an anti-overwetting device 1-4 is arranged at the drying bed part of the feeding point to perform dehumidification and forced ventilation, preventing the pellets at the feeding point from sticking and affecting the smooth feeding. The pellets are gradually dried to the lowest moisture content through the step-by-step drying of the multi-stage vibrating feeding type drying bed device 1-3, completing the entire drying process of the wet pellets;

[0123] The pellets dried in the drying section 1 enter the roasting section 2 of the vertical furnace through the connecting rod type double-layer air-lock sealing valve device 1-9, and the roasting process is completed during the descent in the roasting section. The heat energy for roasting comes from the two combustion chambers 2-1 arranged on the longitudinal sides of the vertical furnace. At least two burners are arranged in each combustion chamber 2-1. The fuel and combustion air are mixed and adjusted through the burners and burned in the combustion chamber to form high-temperature air (flame), and then the high-temperature air (flame) is exchanged and roasted with the pellets through several spout openings arranged longitudinally in the cross-section of the vertical furnace roasting section 2;

[0124] The pellet after roasting gradually and slowly descends into the internal of the toothed crushing and discharging device in the cooling zone. The pellet is discharged into the three-stage solid-solid heat exchange device through the rotation and crushing of the toothed crushing and discharging device. Through the heat exchange in the high-temperature solid-solid heat exchange device 2-10, the medium-temperature solid-solid heat exchange device 2-11, and the low-temperature solid-solid heat exchange device 2-12, the waste heat of the high-temperature pellet is converted into high-temperature air. A part of the high-temperature air after heat exchange enters the combustion chamber for combustion support of the combustion air, improving the combustion temperature of the combustion chamber and reducing the fuel energy consumption. The other part of the high-temperature air enters the drying section for material drying, achieving the energy-saving purpose of full utilization of the waste heat energy. After the heat exchange work is completed, the pellet discharging work is completed by the vibrating ash discharger 2-13 and enters the downstream process.

[0125] The cross-section of the shaft furnace is set in a "double T rectangle" symmetric layout. The drying section and the roasting section inside the furnace body are in a partition structure. Only the air distribution outlet of the in-furnace circulating air channel in the partition part connects the drying section and the roasting section. The heat energy and the flue gas velocity in the drying section all come from the three-stage solid-solid heat exchange device. Through the collection of the in-furnace circulating air channel and the out-of-furnace circulating air channel and the adjustment with the cold air, the purpose of temperature control adjustment and air velocity distribution is achieved.

[0126] Due to the partition structure between the drying section and the roasting section, through the combined application with the connecting rod type double-layer air lock and seal valve device, the purpose of two-stage independent or continuous production is realized. Moreover, the waste gas in the drying section and the flue gas in the roasting section are independently operated and discharged, achieving the maximum reduction of the quantity of harmful waste gas and greatly reducing the investment and treatment difficulty of the harmful gas treatment equipment.

[0127] Next, the specific process flow will be described in detail with reference to the accompanying drawings:

[0128] The high-moisture pellets (water content ≥ 10 - 35%) passing through the pelletizing or briquetting production system are conveyed to the high-low double-track reciprocating shuttle car 1-2 by the feeding conveyor 1-1 (not limited to belt conveyors and large-angle belt conveyors, etc.). The high-moisture pellets enter the drying section 1 through the high-low double-track reciprocating shuttle car 1-2. A cloth car guiding slideway 1-2-1 is arranged in the same direction as the high-low double-track reciprocating shuttle car 1-2 in the sealed air collecting box body 1-14 to ensure the stable operation of the high-low double-track reciprocating shuttle car 1-2. A multi-stage (multi-layer vibrating feeding type drying bed device 1-3 is arranged successively downward at the feeding point of the high-low double-track reciprocating shuttle car 1-2. The high-moisture pellets falling from the head of the high-low double-track reciprocating shuttle car 1-2 gradually fall onto the surface layer of the vibrating feeding type drying bed device 1-3. Each stage of the vibrating feeding type drying bed device 1-3 consists of a "positive umbrella shape" and an "inverted umbrella shape". The "positive umbrella shape" bed surface receives materials on the outer wall, and the "inverted umbrella shape" receives materials on the inner wall of the bed surface. The thickness of the receiving layer is controlled by the drying bed vibrating device 1-3-1, which can independently adjust the material feeding amount and the material heating time. A large amplitude results in a large feeding amount, and a small amplitude results in a small feeding amount. When the vibrating device stops, the feeding stops;

[0129] Since all the moisture (water vapor) in the entire drying section 1 is discharged out of the furnace from the upper center of the sealed air collecting box body 1-14, all the water vapor flows upward successively from the bottom of the vibrating feeding type drying bed device 1-3, resulting in the largest water vapor at its top, which makes the high-moisture pellets entering the drying bed initially prone to adhesion. Through the combined application of the anti-overwet device 1-4 and the dehumidifying fan 1-5, pipeline 1-6, pipeline 1-7, valve 1-8, etc., dehumidification and forced ventilation are carried out, accelerating the exhaust speed and solving the problem of high-moisture pellet adhesion;

[0130] A steam conversion device 1-22 is arranged outside the sealed air collecting box body 1-14. The steam is collected by the steam collecting device 1-22-1 arranged inside the sealed air collecting box body 1-14 and enters the steam conversion device 1-22 for steam distribution and conversion. The generated steam enters the steam drum 1-22-2, and the steam is introduced into the external network steam pipeline through the steam outlet 1-22-4 for production use or domestic use, such as: generating hot water through heat exchange or heating, etc. The condensed water (hot water) generated in the condensate drum 1-22-3 is discharged from the condensate downward port 1-22-5, and the condensed water is introduced into the upstream pelletizing system through a special pipeline for use as production water for green pellets;

[0131] The moisture content of the dried pellets is already less than 1%. The connecting rod type double-layer air-lock and seal valve device 1-9 conveys the dried pellets downward to the roasting section 2. Components such as the upper valve body 1-9-1, the lower valve body 1-9-2, the hydraulic cylinder 1-9-3, and the connecting rod 1-9-4 are arranged on the connecting rod type double-layer air-lock and seal valve device 1-9. Through the reciprocating swing of the hydraulic cylinder 1-9-3 and the connecting rod 1-9-4 connected thereto, the upper valve body 1-9-1 and the lower valve body 1-9-2 are alternately opened to achieve air-lock and material discharging;

[0132] The temperature of the primary drying air is in the range of 400°C to 500°C, and it is supplied after heat exchange with the cold air of the medium-temperature solid-solid heat exchange device 2-11 and the low-temperature solid-solid heat exchange device 2-12 and the cooling fan 2-17;

[0133] Multiple primary drying air outlets 1-10 and multiple primary drying air outlets 1-11 are arranged on the upper part of the in-furnace circulating air channel 2-7 to complete the heat supply and air supply to the entire multi-stage vibrating material discharging type drying bed device 1-3. Since the primary drying air only has a vertical air flow from bottom to top, the drying effect is poor. By introducing the lateral secondary drying air through the secondary drying air pipe 1-12 and the secondary drying air pipe valve 1-13, a lateral air flow will be generated. In this way, there is both a countercurrent in the horizontal direction between the material and the hot air flow and a countercurrent in the vertical direction between the two in the dryer, thus forming a unique mixed-flow drying effect, and the drying effect is very obvious; moreover, the temperature of the lateral secondary drying air is adjustable and can directly enter the cold air, which can achieve the adjustment of the hot air of the entire multi-stage vibrating material discharging type drying bed device 1-3. Since the secondary drying air pipe 1-12 is arranged as multiple groups of elevation inlets on the side wall of the sealed air collection box 1-14, the mixed air distribution can be made more uniform. The temperature of the entire drying bed gradually decreases from 450 to 140°C from bottom to top, and all the dust-containing gas at 70 to 120°C after completing the drying work is discharged out of the furnace through the drying section dust removal main pipe 1-15 arranged on the upper part of the sealed air collection box 1-14 and enters an independent waste-free dust removal system;

[0134] The powder screening device 1-16 at the bottom of the vibrating material discharging type drying bed device 1-3 screens the powder particles generated during the drying process into the internal part of the powder collection bin 1-17, and they fall into the primary drying air outlet 1-11 through the gravity of the material and enter the internal part of the in-furnace circulating air channel 2-7. During the falling process, they form a "suspension" type of descent with the rising waste gas pressure and flow rate, and complete roasting during the falling process. After completing roasting, the powder directly descends to the bottom of the in-furnace circulating air channel 2-7 and is collected into the internal part of the powder collection bin 2-8-1 of the out-of-furnace circulating air channel 2-8. The release valve 2-8-2 arranged at the lower part of the powder collection bin 2-8-1 regularly releases the powder into the powder collection tank 2-8-4 through the powder descending pipe 2-8-3 to complete the powder collection work;

[0135] When the dried green pellets fall to the roasting area of the shaft furnace roasting section 2 through the connecting rod type double-layer air-lock seal valve device 1-9, the production process flow of the entire drying section is completed, and the roasting process is carried out in the shaft furnace roasting section 2;

[0136] Combustion chambers 2-1 are symmetrically arranged on both sides of the furnace body of the roasting section 2. Each combustion chamber 2-1 is provided with two gas fuel burners 2-2 and one solid fuel burner 2-3 at each end face. When producing with gas fuel, combustion-supporting air is introduced through the first combustion-supporting air pipeline 2-2-1, and gas is introduced through the gas pipeline 2-2-2. When using solid fuel, the fuel is introduced into the solid fuel burner 2-3 through the solid fuel conveying pipeline 2-3-1;

[0137] The dried green pellets first enter the preheating zone at the top of the roasting section 2 for preheating roasting. The preheated pellets slowly descend and are evenly arranged on both sides of the in-furnace circulating air channel 2-7, forming two roasting zones with the same capacity and operating synchronously. When the pellets slowly descend together from the two zones to the roasting zone, they exchange heat and roast with the hot flames blown from several spout openings arranged longitudinally in the cross-section of the shaft furnace. The high-temperature flame of the spout opening can reach 900-1200°C, and its flame and heat source come from inside the combustion chambers 2-1 symmetrically arranged on both sides of the furnace body of the roasting section 2. During the roasting process, the high-temperature waste gas rises to the top of the shaft furnace roasting section and enters the high-temperature waste gas waste heat heat exchange device 1-20 through the inclined air outlet 1-19 for heat exchange. The high-temperature waste gas enters through the high-temperature waste gas inlet 1-20-1 and exchanges heat with the cold air entering through the cold air regulating inlet 1-20-2. The heated high-temperature air enters the drying secondary air pipeline 1-12 through the high-temperature air outlet 1-20-3, and after being adjusted by the drying secondary air pipeline valve 1-13, it enters the sealed gas collection box 1-14 to participate in drying. The waste gas after heat exchange is introduced into an independent flue gas dust removal system through the total waste gas outlet pipe 1-21 after heat exchange;

[0138] The roasted pellets slowly descend to the heat exchange and cooling section and enter the toothed crushing and discharging device 2-9 for crushing and discharging. The toothed crushing and discharging device 2-9 has two functions of crushing and discharging, and a set of rotating bodies with toothed structures are arranged inside. When the agglomerated materials enter, they are crushed and discharged during the rotation process; the discharging speed depends on the rotation speed of the toothed crushing and discharging device 2-9, and its rotation speed (discharging amount) depends on the discharging amount (vibration frequency) of the vibrating ash discharger 2-13. The toothed crushing and discharging device 2-9 and the vibrating ash discharger 2-13 operate synchronously as a group;

[0139] The material discharged from the toothed crusher discharger 2-9, which is high-temperature pellet material with a temperature in the range of 600 - 700 °C, first enters the high-temperature solid-solid heat exchange device 2-10 at the upper part of the heat exchange and cooling section, where it exchanges heat with the combustion-supporting cold air entering from the combustion-supporting air inlet 2-10-1. It enters the hot air rising pipe 2-10-3 through a set of external circulation pipes one 2-10-2, and after being regulated by the valve three 2-10-4, it enters the gas fuel burner 2-2 arranged on the end face of the combustion chamber 2-1 to participate in the burner combustion. The temperature of the combustion-supporting air after heat exchange in the high-temperature solid-solid heat exchange device 2-10 can reach above 450 °C, which can increase the flame temperature in the combustion chamber by more than 250 °C, effectively increasing the roasting temperature of the entire roasting section 2 and effectively reducing the fuel energy consumption; the heat exchange air of the high-temperature solid-solid heat exchange device 2-10 comes from the combustion-supporting fan 2-16;

[0140] After heat exchange in the high-temperature solid-solid heat exchange device 2-10, the temperature of the material drops to the range of 450 - 550 °C, and it slowly descends to the medium-temperature solid-solid heat exchange device 2-11, where it continues to exchange heat with the low-temperature hot air from the low-temperature solid-solid heat exchange device 2-12. After the heat exchange is completed, the material descends into the low-temperature solid-solid heat exchange device 2-12 to complete the furnace discharge work;

[0141] The waste heat energy of the furnace external material discharged into the low-temperature solid-solid heat exchange device 2-12 is still in the range of 250 - 350 °C. Through heat exchange with the cooling air at the cooling air inlet 2-12-1, the temperature of the cold air is raised to above 150 °C. The hot air after heat exchange enters the medium-temperature solid-solid heat exchange device 2-11 through the hot air outlet one 2-12-2 and the external circulation pipe two 2-12-3, and the temperature of the material slowly descending inside is raised. When it is raised to the range of 350 - 450 °C, it enters the furnace external circulation air channel 2-8 through the hot air outlet two 2-12-4 and the hot air rising pipe two 2-12-5, and rises through the furnace internal circulation air channel 2-7 into the internal part of the drying section 1 of the shaft furnace. The air volume distribution of the furnace internal circulation air channel 2-7 is realized by a plurality of drying primary air outlets one 1-10 and drying primary air outlets two 1-11 arranged on its upper part; the temperature of the drying air is controlled by the cold air in the secondary air mixing pipe 2-15. When the temperature of the drying air is higher than the required temperature of the drying section 1, the regulating valve 2-15-1 is opened for air mixing and temperature adjustment;

[0142] The cooling air of the low-temperature solid-solid heat exchange device 2-12 comes from the cooling fan 2-17 and enters through the cooling air inlet 2-12-1. After the pellet material in the low-temperature solid-solid heat exchange device 2-12 completes the heat exchange work, it is discharged by the vibrating ash discharger 2-13 to complete the pellet discharging work and enters the downstream process;

[0143] The vibrating ash discharger 2-15 is set as four independent discharging units that are arranged symmetrically side by side. The corresponding high-temperature solid-solid heat exchange device 2-10, medium-temperature solid-solid heat exchange device 2-11, and low-temperature solid-solid heat exchange device 2-12 are also set as four groups. Their heat energy exchange and pellet material cooling form a countercurrent heat exchange system, that is, the material achieves the cooling purpose during the descending process, and the air achieves the purposes of temperature rise, waste heat energy recovery, exchange, and application during the ascending process. At the same time, by setting the discharging at four points symmetrically, the functions of balanced discharging on both sides of the in-furnace circulating air channel 2-7 and local single-point adjustment of the discharging amount can be realized. Thus, the entire drying and roasting production processes of the shaft furnace are completed.

[0144] Embodiment 2 (Route 2):

[0145] When producing metallurgical pellets and lime, small-sized granular stones with a particle size of 5-20 mm are mainly used for production. The running speeds and discharging amounts of the feeding conveyor 1-1 and the high-low double-rail reciprocating shuttle car 1-2 in the drying section 1 are adjusted. When producing metallurgical pellets, the discharging amount is about 30% (weight ratio) of the phosphate ore pellets. When producing lime, the discharging amount is about 30% (weight ratio) of the phosphate ore pellets.

[0146] During production, the anti-over-wetting device 1-4 is closed, the temperature of the combustion chamber 2-1 is adjusted and increased to above 1100 °C, the drying section 1 is adjusted to the preheating zone, and the temperatures at the upper outlet of the sealed gas collection box body 1-14 and the dust removal main pipe 1-15 in the drying section are adjusted and controlled within the range of 140-250 °C. When the material descends to the cooling zone, the cooling air in the secondary combustion-supporting air pipe 2-14 is introduced for cooling. The secondary combustion-supporting air has the functions of both cooling and secondary combustion during the production of metallurgical pellets, and also has the function of oxygen increase and reduction, achieving the purpose of oxidative-reductive roasting of metallurgical pellets. In lime production, the cooling air has the functions of cooling and secondary combustion. After the above operations are completed, the other production processes in Scheme 1 are repeated to complete the entire calcination processes of metallurgical pellet ore and lime.

[0147] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. These embodiments that are not explicitly written should also be considered to be within the scope described in this specification.

Claims

1. A segmented baking integrated vertical furnace for high-humidity non-metallic tailings pellets, characterized in that: It comprises a vertical furnace body, which is a three-section structure of upper, middle and lower sections, the upper section is a drying section, the middle section is a roasting section, and the lower section is a heat exchange cooling section; The inlet end of the drying section is connected to the feeding conveyor through a high and low double-track reciprocating shuttle type material distribution vehicle, and a multi-stage vibrating material-discharging drying bed device is arranged below the discharge point of the high and low double-track reciprocating shuttle type material distribution vehicle in the drying section, and a powder material collecting bin 1 is arranged at the lower part of the vibrating material-discharging drying bed device; A middle partition is provided between the roasting section and the drying section, an in-furnace circulating air channel connected to the first powder collecting bin is longitudinally provided at the inner center position of the roasting section, two roasting areas are formed on both sides of the in-furnace circulating air channel, and a connecting rod type double-layer air-locking sealing valve device for connecting the roasting section and the drying section is provided at the upper part of each roasting area, a drying primary air outlet is provided at the upper part of the in-furnace circulating air channel for supplying heat and air to the vibrating unloading drying bed device; two combustion chambers are symmetrically provided on both sides of the roasting section furnace body; an out-furnace circulating air channel is provided at the bottom of the in-furnace circulating air channel, and the out-furnace circulating air channel is connected to the second powder collecting bin; A toothed crushing discharger is arranged between the heat exchange cooling section and the roasting section, a vibrating ash discharger is arranged at the bottom of the heat exchange cooling section, and the heat exchange cooling section is provided with a cooling air inlet and is connected to a hot air rising duct 1 and a hot air rising duct 2, the hot air rising duct 1 is communicated with the combustion chamber, and the hot air rising duct 2 is communicated with the external circulating air channel of the furnace.

2. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: The heat exchange cooling section adopts a three-stage solid-solid heat exchanger, which is divided into a high-temperature solid-solid heat exchange device, a medium-temperature solid-solid heat exchange device, and a low-temperature solid-solid heat exchange device arranged from top to bottom. The outlet of the toothed crushing discharger is connected to the high-temperature solid-solid heat exchange device, and the high-temperature solid-solid heat exchange device is provided with a combustion air inlet and a hot air outlet 2, and a plurality of groups of external circulation pipes 1 are arranged outside the high-temperature solid-solid heat exchange device, and the external circulation pipes 1 are connected to the combustion chamber through the hot air rising pipe 1, and the hot air outlet 2 is connected to the hot air rising pipe 2, and the hot air rising pipe 2 is also connected to the secondary mixed air pipe; The low-temperature solid-solid heat exchange device is provided with a cooling air inlet and a hot air outlet. The hot air outlet is connected to the medium-temperature solid-solid heat exchange device through an external circulation pipe. The cooling air inlet is connected to the cooling fan. The vibrating ash discharger is located at the bottom of the low-temperature solid-solid heat exchange device.

3. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: The connecting rod type double-layer air-locking sealing valve device comprises an upper valve body located at the upper part and a lower valve body located at the lower part, and the upper valve body and the lower valve body are connected to the hydraulic cylinder through a connecting rod; It also includes an air lock sealing component, which includes a multi-point unloading control valve and is respectively installed on the upper valve body and the lower valve body.

4. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: The drying section is composed of a sealed gas collecting box made of steel structure, a steam conversion device is arranged on the outside of the sealed gas collecting box, a steam collecting device connected to the steam conversion device is arranged on the inside of the sealed gas collecting box, the steam conversion device is connected to the condensate drum through a steam bag, a steam outlet is arranged on the top of the steam bag, and a condensate descending port is arranged on the bottom of the condensate drum.

5. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 4, characterized in that: A drying section dust removal main pipe is arranged on the top of the sealed air collecting box body, and an oblique air outlet is arranged on the top of the roasting section furnace body. The oblique air outlet is connected to a high-temperature exhaust gas waste heat heat exchange device. A high-temperature exhaust gas inlet, a cold air regulating inlet and a high-temperature air outlet are arranged on the high-temperature exhaust gas waste heat exchange device. The high-temperature air outlet is connected to a drying secondary air duct. The high-temperature exhaust gas waste heat exchange device is also connected to a flue gas dust removal system through the exhaust gas outlet main pipe after heat exchange.

6. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: An anti-over-humidification device is provided on the upper part of the vibration unloading drying bed device; The vibrating unloading drying bed device adopts a multi-stage vertical arrangement, and each stage structure adopts a "positive umbrella shape" and an "inverted umbrella shape" composition mode. The "positive umbrella shape" bed body receives materials outside the outer wall of the bed surface, and the "inverted umbrella shape" bed body receives materials inside the inner wall of the bed surface. The bed surface adopts a horizontal louver structure.

7. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: The roasting section furnace body adopts a "T"-shaped vertical closed structure, and the cross section is a symmetrical double-chamber rectangular structure. The bottom of the roasting section furnace body is located below the combustion chamber and is provided with a secondary combustion air duct; The two combustion chambers are each provided with at least two gas fuel burners and at least one solid fuel burner on the end surface, the gas fuel burner is connected to a combustion air duct, and the solid fuel burner is connected to a solid fuel delivery duct; the combustion chamber is arranged in a circular or rectangular shape, and the fuel of the combustion chamber is yellow phosphorus tail gas, biomass gas or natural gas and powdered sprayable solid fuel; The powder collecting bin 2 is connected to the powder collecting tank through a powder descending pipe.

8. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: The vibrating ash discharger is configured as four or more independent discharging units which are arranged symmetrically in parallel, and the corresponding high-temperature solid-solid heat exchange devices, medium-temperature solid-solid heat exchange devices and low-temperature solid-solid heat exchange devices are also configured as four or more groups.

9. The integrated vertical furnace for baking high-humidity non-metallic tailings pellets according to claim 1, characterized in that: The high and low double-track reciprocating shuttle type material distribution vehicle comprises a material distribution vehicle body, a traveling guide rail for a vehicle body outside the furnace and a guide rail inside the furnace. The traveling guide rail for the vehicle body outside the furnace is used to provide support and guidance for the movement of the material distribution vehicle body, and the traveling guide rail for the vehicle body outside the furnace is combined with the guide rail inside the furnace. A material distribution device is provided at the front end of the material distribution vehicle body, and a guide traveling wheel is provided at the head of the material distribution device, and a material discharge port is provided at the head of the material distribution device.

10. A process for a segmented baking integrated vertical furnace for high-humidity non-metallic tailings pellets, characterized in that: The segmented baking integrated vertical furnace for high-humidity non-metallic tailings pellets according to any one of claims 1 to 9 is used, and the process comprises the following steps: The wet pellets that have passed through the pelletizing or pelletizing production system are transported to the upper part of the high and low double-track reciprocating shuttle distribution vehicle through the feeding conveyor. The pellets enter the drying section through the high and low double-track reciprocating shuttle distribution vehicle for uniform reciprocating distribution. The wet pellets are dried step by step by the multi-stage vibrating feeding drying bed device so that the moisture of the pellets is gradually dried to the lowest point, completing the entire drying process of the wet pellets; After being dried in the drying section, the pellets enter the roasting section through a connecting rod type double-layer air-locking sealing valve device. During the descent process in the roasting section, the pellets exchange heat with the hot flames sprayed by several burners arranged longitudinally in the cross section of the drying section for roasting; The roasted pellets gradually and slowly descend into the toothed crushing discharger, and are discharged into the heat exchange cooling section through the rotation and crushing of the toothed crushing discharger. Heat is exchanged through the heat exchange cooling section to convert the waste heat of the high-temperature pellets into high-temperature air. Part of the high-temperature air after heat exchange enters the combustion chamber for combustion-supporting air, and the other part of the high-temperature air enters the drying section for material drying. After the heat exchange work is completed, the pellets are discharged by the vibrating ash discharger to complete the discharging work and enter the downstream process.

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