An apparatus and method for microwave magnetization roasting of siderite

Abstract

The present invention relates to the technical field of metallurgical magnetization roasting equipment, and specifically relates to a microwave magnetization roasting device and method for siderite, including a feeding belt conveyor, a microwave magnetization roasting vertical furnace, and a desulfurization tower. The top of the microwave magnetization roasting vertical furnace is connected to an oxidation exothermic vertical furnace, the top of the oxidation exothermic vertical furnace is connected to a preheating vertical furnace, and the top of the preheating vertical furnace is connected to a drying vertical furnace. Under the action of the waste heat transfer mechanism and its connecting components, the thermal energy is comprehensively utilized, greatly saving energy consumption. The energy consumption per ton of treatment is reduced to less than 100 degrees of electricity, significantly reducing the production cost. The present invention uses microwaves for auxiliary catalytic heating, greatly accelerating the decomposition time of siderite and improving the production capacity. At the same time, straw, wheat straw, biochemical sludge, etc. are fully utilized as fuels during the production process, contributing to the comprehensive utilization of resources.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical magnetization roasting equipment, and particularly to a microwave magnetization roasting device and method for siderite. Background Art

[0002] Lean ores are represented by siderite. The ore minerals of siderite are complex in composition and often occur as isomorphous symbiosis with calcium, manganese, magnesium, etc., resulting in low iron grade and difficulty in large-scale development and utilization. The traditional equipment for roasting siderite is a rotary kiln, and the inherent process characteristics of the rotary kiln determine its limitations in terms of energy consumption, throughput, efficiency, etc. The main reasons are mainly reflected in the following aspects:

[0003] 1. In the rotary kiln, the materials often accumulate at the bottom of the kiln, and the gas flow passes over the surface of the material layer; this accumulation state leads to a relatively small contact area between the gas flow and the materials, and it is difficult for the gas flow to penetrate into the interior of the material layer, thus limiting the heat transfer efficiency. Due to the limited contact area, the heat transfer is not sufficient, resulting in a slow heat transfer speed and reduced efficiency;

[0004] 2. The waste gas generated after heating the materials by traditional equipment is often directly filtered and discharged. However, this part of the waste gas is often at a high temperature, and the direct discharge is difficult to handle, and the heat is not utilized, resulting in heat waste;

[0005] Therefore, in view of the deficiencies of the low operation rate and high production cost of the traditional rotary kiln, we propose a microwave magnetization roasting device and method for siderite. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a microwave magnetization roasting device for siderite, including a feeding belt conveyor, a microwave magnetization roasting vertical furnace, and a desulfurization tower. The top of the microwave magnetization roasting vertical furnace is connected to an oxidation exothermic vertical furnace, the top of the oxidation exothermic vertical furnace is connected to a preheating vertical furnace, the top of the preheating vertical furnace is connected to a drying vertical furnace, and the drying vertical furnace is connected to the feeding belt conveyor for preliminarily drying the siderite conveyed by the feeding belt conveyor;

[0007] It further includes a first slow cooling shaft furnace connected to the bottom end of the microwave magnetization shaft furnace. The bottom end of the first slow cooling shaft furnace is connected to a second slow cooling shaft furnace. The top end of the second slow cooling shaft furnace is connected to the first slow cooling shaft furnace, and the bottom end is connected to a third slow cooling shaft furnace. The top end of the third slow cooling shaft furnace is connected to the bottom end of the second slow cooling shaft furnace, and the bottom end is connected to a discharging shaft furnace. The top end of the discharging shaft furnace is connected to the bottom end of the third slow cooling shaft furnace, and the bottom end is connected to a water quenching tank. A heat exchange coil is arranged in the water quenching tank. The distribution state is as follows: the drying shaft furnace, the preheating shaft furnace, the oxidation exothermic shaft furnace, the microwave magnetization roasting shaft furnace, the first slow cooling shaft furnace, the second slow cooling shaft furnace, the third slow cooling shaft furnace, the discharging shaft furnace, and the water quenching tank are connected in series and sealed from top to bottom. The siderite moves downward by gravity, and the hot gas heated by the heat exchange coil in the water quenching tank moves upward and is discharged from the drying shaft furnace;

[0008] It further includes a waste heat transfer mechanism connected to the desulfurization tower, the drying shaft furnace, the preheating shaft furnace, the oxidation exothermic shaft furnace, the microwave magnetization roasting shaft furnace, the first slow cooling shaft furnace, the second slow cooling shaft furnace, and the third slow cooling shaft furnace, and a finished product processing mechanism installed on the water quenching tank. The waste heat transfer mechanism utilizes the heat energy in the components connected to it to perform corresponding thermal processing on the siderite, and the finished product processing mechanism performs ball milling and screening on the preliminarily processed siderite to transform it into iron concentrate.

[0009] Preferably, a wind guiding wall is arranged in the microwave magnetization roasting shaft furnace, and a microwave heater is arranged on the outer wall. Air holes are evenly arranged on the wind guiding wall. The microwave heater provides microwave energy for the microwave magnetization roasting shaft furnace, and the microwave energy evenly heats the siderite and catalyzes the decomposition reaction.

[0010] Preferably, an exhaust port is opened at the top end of the drying shaft furnace, and a feeding port is arranged on the drying shaft furnace. The feeding port is located at the discharging end of the feeding belt conveyor. A first air cap is arranged in the drying shaft furnace, and the first air cap evenly disperses the hot air in the drying shaft furnace.

[0011] Preferably, a second air cap is arranged in the preheating shaft furnace. The second air cap has the function of evenly dispersing hot air. This part of the hot air comes from the second slow cooling shaft furnace and is used to preheat the mixture composed of siderite and additives in this section.

[0012] Preferably, a third air cap is arranged in the oxidation exothermic shaft furnace. The third air cap has the function of evenly dispersing hot air. This part of the hot air comes from the first slow cooling shaft furnace, and the additive burns and releases heat in this section, which is used to heat the siderite.

[0013] Preferably, the waste heat transfer mechanism includes a first heat exchanger, a second heat exchanger, and a third heat exchanger respectively arranged in the first slow cooling shaft furnace, the second slow cooling shaft furnace, and the third slow cooling shaft furnace. The first heat exchanger, the second heat exchanger, and the third heat exchanger are all made of heat-conducting metal materials;

[0014] It also includes a first heat exchanger, a second heat exchanger, and a third heat exchanger disposed on one side of the first slow-cooling shaft furnace, the second slow-cooling shaft furnace, and the third slow-cooling shaft furnace. The first heat exchanger, the second heat exchanger, and the third heat exchanger are respectively connected to one side of the first heat exchanger, the second heat exchanger, and the third heat exchanger through pipelines, and they are interconnected with each other and distributed in a straight line. The exhaust port on the drying shaft furnace is communicated with the inlet end of the first heat exchanger, and the outlet end of the third heat exchanger is connected to the desulfurization tower;

[0015] It also includes a combustion-supporting blower, a first blower, and a second blower. The air inlets of the combustion-supporting blower, the first blower, and the second blower are respectively connected to the first heat exchanger, the second heat exchanger, and the third heat exchanger. The air outlet of the combustion-supporting blower is respectively connected to the air guiding wall in the microwave magnetization roasting shaft furnace and the third air cap in the oxidation heat-releasing shaft furnace through pipelines. The air outlets of the first blower and the second blower are respectively connected to the second air cap in the preheating shaft furnace and the first air cap in the drying shaft furnace.

[0016] Preferably, the finished product processing mechanism includes a toothed roll unloader disposed in the discharging shaft furnace, and also includes a scale conveyor disposed in the water quenching tank. The end of the scale conveyor is connected to a ball mill, and a magnetic separator is provided at the discharge port of the ball mill.

[0017] Preferably, a dust collector is provided between the desulfurization tower and the third heat exchanger. The inlet of the dust collector is communicated with the outlet of the third heat exchanger, and the outlet is communicated with the inlet of the desulfurization tower.

[0018] Preferably, an induced draft fan is provided at the top of the desulfurization tower, and a chimney is provided on the induced draft fan.

[0019] A usage method of a microwave magnetization roasting device for siderite: includes the following steps:

[0020] S1: First, crush the siderite into small pieces of 10 - 30 mm, and put the crushed siderite and additives into the feeding belt conveyor according to a ratio. Subsequently, through the transmission of the feeding belt conveyor, the siderite and additives enter the drying shaft furnace. The mass ratio of the siderite to the additives is 10:0.5 to 10:1, and the additives are solids such as straw, wheat straw, and dried biochemical sludge with a certain calorific value and a relatively low ignition point;

[0021] S2: The siderite and additives are dried in the drying shaft furnace, and the drying temperature is 100 - 150 °C. The heat source comes from two parts: one part is the hot air moving upward in the preheating shaft furnace; the other part is that the normal-temperature air is heated to 50 - 60 °C by the third heat exchanger, then heated to 300 - 350 °C by the third heat exchanger, and then blown into the first air cap by the second blower and evenly dispersed;

[0022] S3: The siderite and additives are preheated to above 300°C in the preheating shaft furnace. The heat source comes from two parts: one part is the hot gas moving upward in the oxidation exothermic shaft furnace; the other part is the normal-temperature air heated to 80 - 90°C by the second heat exchanger, then heated to 400 - 450°C by the second heat exchanger, and then blown into the second air cap by the first blower and evenly dispersed.

[0023] S4: The siderite and additives are preheated to above 450°C in the oxidation exothermic shaft furnace. The heat source comes from four parts: the first part is the hot gas moving upward in the microwave magnetization roasting shaft furnace; the second part is the hot gas generated by the oxidation exothermic of CO in the air guiding wall moving upward; the third part is the large amount of heat released by the oxidation reaction of the additives; the fourth part is the normal-temperature air heated to 110 - 120°C by the first heat exchanger, then heated to 500 - 550°C by the first heat exchanger, and then blown into the third air cap by the combustion-supporting blower and evenly dispersed.

[0024] S5: The siderite is microwave-catalyzed and heated to 600 - 700°C in the microwave magnetization roasting shaft furnace. The siderite is rapidly decomposed, and the generated CO and CO 2 gas permeates into the air guiding wall, and the CO gas in it undergoes an oxidation reaction to release heat and move upward, preheating the siderite in the shaft furnace above it.

[0025] S6: The decomposed iron ore is cooled to 250 - 300°C in the first slow cooling shaft furnace, the second slow cooling shaft furnace, and the third slow cooling shaft furnace, then discharged to the water in the water quenching tank by the toothed roll unloader for anaerobic water quenching. The water-quenched iron ore is scraped out of the water quenching tank by the scale board machine, then ball-milled by the ball mill, and then the Fe3O4 is selected by the magnetic separator.

[0026] S7: The generated flue gas is cooled to below 100°C after heat exchange in the first heat exchanger, the second heat exchanger, and the third heat exchanger, then the particulate matter is removed by the dust collector, and then the SO in the flue gas is removed by the desulfurization tower 2 , and finally it is blown into the chimney by the induced draft fan and discharged up to the standard.

[0027] The present invention has at least the following beneficial effects:

[0028] 1. Under the action of the waste heat transfer mechanism and its connecting components, the hot air flow heats the materials in each furnace from bottom to top in turn, fully contacts with the materials, and comprehensively utilizes the heat energy, greatly saving energy consumption. The energy consumption per ton of treatment is reduced to below 100 degrees of electricity, and the production cost is greatly reduced.

[0029] 2. The present invention uses microwave for auxiliary catalytic heating, greatly accelerating the decomposition time of siderite and improving the production capacity. At the same time, straw, wheat straw, biochemical sludge, etc. are fully utilized as fuels during the production process, contributing to the comprehensive utilization of resources.

[0030] 3. The reasonable distribution of parts in the present invention makes the overall equipment occupy a small area, greatly reducing the site cost required during construction, and has a good magnetization roasting effect. The iron grade of siderite is increased from 40 - 43% to 62 - 65%. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 is a schematic diagram of the structure from another perspective of the present invention;

[0033] Figure 3 is a schematic diagram of the two - dimensional internal structure of the present invention.

[0034] In the figure: 1. Feeding belt conveyor; 2. Drying vertical furnace; 201. Exhaust port; 202. Feeding port; 203. First air cap; 3. Preheating vertical furnace; 301. Second air cap; 4. Oxidation exothermic vertical furnace; 401. Third air cap; 5. Microwave magnetization roasting vertical furnace; 501. Air guiding wall; 502. Microwave heater; 6. First slow - cooling vertical furnace; 601. First heat exchanger; 7. Second slow - cooling vertical furnace; 701. Second heat exchanger; 8. Third slow - cooling vertical furnace; 801. Third heat exchanger; 9. Discharging vertical furnace; 901. Tooth - roll discharger; 10. Quenching tank; 1001. Heat - exchange coil; 11. Combustion - supporting blower; 12. First blower; 13. Second blower; 14. Scaling machine; 15. Ball mill; 16. Magnetic separator; 17. First heat exchanger; 18. Second heat exchanger; 19. Third heat exchanger; 20. Dust collector; 21. Desulfurization tower; 22. Induced draft fan; 23. Chimney. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0036] Please refer to Figures 1-3 , the present invention provides a technical solution: a siderite microwave magnetization roasting device, including a feeding belt conveyor 1, a microwave magnetization roasting vertical furnace 5 and a desulfurization tower 21. The top of the microwave magnetization roasting vertical furnace 5 is connected to an oxidation exothermic vertical furnace 4, the top of the oxidation exothermic vertical furnace 4 is connected to a preheating vertical furnace 3, the top of the preheating vertical furnace 3 is connected to a drying vertical furnace 2, and the drying vertical furnace 2 is connected to the feeding belt conveyor 1 for preliminarily drying the siderite conveyed by the feeding belt conveyor 1;

[0037] It further includes a first slow cooling shaft furnace 6 connected to the bottom end of the microwave magnetization shaft furnace, a second slow cooling shaft furnace 7 connected to the bottom end of the first slow cooling shaft furnace 6, the top end of the second slow cooling shaft furnace 7 is connected to the first slow cooling shaft furnace 6, the bottom end is connected to a third slow cooling shaft furnace 8, the top end of the third slow cooling shaft furnace 8 is connected to the bottom end of the second slow cooling shaft furnace 7, the bottom end is connected to a discharging shaft furnace 9, the top end of the discharging shaft furnace 9 is connected to the bottom end of the third slow cooling shaft furnace 8, the bottom end is connected to a water quenching tank 10, and a heat exchange coil 1001 is arranged in the water quenching tank 10. The distribution state is that the drying shaft furnace 2, the preheating shaft furnace 3, the oxidation exothermic shaft furnace 4, the microwave magnetization roasting shaft furnace 5, the first slow cooling shaft furnace 6, the second slow cooling shaft furnace 7, the third slow cooling shaft furnace 8, the discharging shaft furnace 9, and the water quenching tank 10 are connected in series and sealed from top to bottom. The siderite moves downward by gravity, and the hot gas heated by the heat exchange coil 1001 in the water quenching tank 10 moves upward and is discharged from the drying shaft furnace 2;

[0038] It further includes a waste heat transfer mechanism connected to the desulfurization tower 21, the drying shaft furnace 2, the preheating shaft furnace 3, the oxidation exothermic shaft furnace 4, the microwave magnetization roasting shaft furnace 5, the first slow cooling shaft furnace 6, the second slow cooling shaft furnace 7, and the third slow cooling shaft furnace 8, and a finished product processing mechanism installed on the water quenching tank 10. The waste heat transfer mechanism utilizes the heat energy in the components connected to it to perform corresponding heat treatment on the siderite, and the finished product processing mechanism performs ball milling and screening on the siderite after being processed by the waste heat transfer mechanism to convert it into iron concentrate.

[0039] The design of vertical series connection between each component greatly reduces the floor area of the overall equipment.

[0040] A wind guiding wall 501 is arranged in the microwave magnetization roasting shaft furnace 5, and a microwave heater 502 is arranged on the outer wall. Air holes are evenly arranged on the wind guiding wall 501. The microwave heater 502 provides microwave energy for the microwave magnetization roasting shaft furnace 5, and the microwave energy evenly heats the siderite and catalyzes the decomposition reaction.

[0041] An exhaust port 201 is opened at the top end of the drying shaft furnace 2, and a feed inlet 202 is arranged on the drying shaft furnace 2. The feed inlet 202 is located at the discharge end of the feed belt conveyor 1. A first air cap 203 is arranged in the drying shaft furnace 2, and the first air cap 203 evenly disperses the hot air in the drying shaft furnace 2.

[0042] A second air cap 301 is arranged in the preheating shaft furnace 3. The second air cap 301 has the function of evenly dispersing hot air. This part of the hot air comes from the second slow cooling shaft furnace 7 and is used to preheat the mixture of siderite and additives in this section.

[0043] A third air cap 401 is arranged in the oxidation exothermic shaft furnace 4. The third air cap 401 has the function of evenly dispersing hot air. This part of the hot air comes from the first slow cooling shaft furnace 6, and the additive burns and releases heat in this section, which is used to heat the siderite.

[0044] The waste heat transfer mechanism includes a first heat exchanger 601, a second heat exchanger 701, and a third heat exchanger 801 respectively arranged in the first slow cooling vertical furnace 6, the second slow cooling vertical furnace 7, and the third slow cooling vertical furnace 8. The first heat exchanger 601, the second heat exchanger 701, and the third heat exchanger 801 are all made of heat-conducting metal materials. The air in each heat exchanger exchanges heat indirectly with siderite to avoid the oxidation of Fe 3 O 4 ;

[0045] It also includes a first heat exchanger 17, a second heat exchanger 18, and a third heat exchanger 19 arranged on one side of the first slow cooling vertical furnace 6, the second slow cooling vertical furnace 7, and the third slow cooling vertical furnace 8. The first heat exchanger 17, the second heat exchanger 18, and the third heat exchanger 19 are respectively connected to one side of the first heat exchanger 601, the second heat exchanger 701, and the third heat exchanger 801 through pipelines, and the three are interconnected and distributed in a straight line. The exhaust port 201 on the drying vertical furnace 2 is communicated with the inlet end of the first heat exchanger 17, and the outlet end of the third heat exchanger 19 is connected to the desulfurization tower 21;

[0046] It also includes a combustion-supporting blower 11, a first blower 12, and a second blower 13. The air inlets of the combustion-supporting blower 11, the first blower 12, and the second blower 13 are respectively connected to the first heat exchanger 601, the second heat exchanger 701, and the third heat exchanger 801. The air outlet of the combustion-supporting blower 11 is respectively connected to the air guide wall 501 in the microwave magnetization roasting vertical furnace 5 and the third air cap 401 in the oxidation exothermic vertical furnace 4 through pipelines. The air outlets of the first blower 12 and the second blower 13 are respectively connected to the second air cap 301 in the preheating vertical furnace 3 and the first air cap 203 in the drying vertical furnace 2.

[0047] The finished product processing mechanism includes a toothed roll unloader 901 arranged in the discharging vertical furnace 9, and also includes a scale conveyor 14 arranged in the quenching tank 10. The end of the scale conveyor 14 is connected to a ball mill 15, and a magnetic separator 16 is arranged at the discharge port of the ball mill 15.

[0048] A dust collector 20 is arranged between the desulfurization tower 21 and the third heat exchanger 19. The inlet of the dust collector 20 is communicated with the outlet of the third heat exchanger 19, and the outlet is communicated with the inlet of the desulfurization tower 21.

[0049] An induced draft fan 22 is arranged at the top of the desulfurization tower 21, and a chimney 23 is arranged on the induced draft fan 22.

[0050] A method for using a siderite microwave magnetization roasting device: includes the following steps:

[0051] S1: First, break the siderite into small pieces of 10 - 30 mm. Put the crushed siderite and additives into the feeding belt conveyor 1 in proportion. Subsequently, through the transmission of the feeding belt conveyor 1, the siderite and additives enter the drying shaft furnace 2. The mass ratio of the siderite to the additives is 10:0.5 to 10:1. The additives are solids with a certain calorific value and a relatively low ignition point, such as straw, wheat straw, and dried biochemical sludge.

[0052] S2: The siderite and additives are dried in the drying shaft furnace 2. The drying temperature is 100 - 150 °C. The heat source comes from two parts: one part is the hot air moving upward in the preheating shaft furnace 3; the other part is that the normal-temperature air is heated to 50 - 60 °C by the third heat exchanger 19, and then heated to 300 - 350 °C by the third heat exchanger 801, and then blown into the first air cap 203 by the second blower 13 and evenly dispersed.

[0053] S3: The siderite and additives are preheated to above 300 °C in the preheating shaft furnace 3. The heat source comes from two parts: one part is the hot air moving upward in the oxidation exothermic shaft furnace 4; the other part is that the normal-temperature air is heated to 80 - 90 °C by the second heat exchanger 18, and then heated to 400 - 450 °C by the second heat exchanger 701, and then blown into the second air cap 301 by the first blower 12 and evenly dispersed.

[0054] S4: The siderite and additives are preheated to above 450 °C in the oxidation exothermic shaft furnace 4. The heat source comes from four parts: the first part is the hot air moving upward in the microwave magnetization roasting shaft furnace 5; the second part is the hot air generated by the oxidation exotherm of CO in the air guiding wall 501 moving upward; the third part is that a large amount of heat is released due to the oxidation reaction of the additives; the fourth part is that the normal-temperature air is heated to 110 - 120 °C by the first heat exchanger 17, and then heated to 500 - 550 °C by the first heat exchanger 601, and then blown into the third air cap 401 by the combustion-supporting blower 11 and evenly dispersed.

[0055] S5: The siderite is microwave-catalyzed and heated to 600 - 700 °C in the microwave magnetization roasting shaft furnace 5. The siderite is rapidly decomposed, and the generated CO and CO 2 gas penetrates into the air guiding wall 501, and the CO gas therein undergoes an oxidation reaction in the air guiding wall 501 to release heat and move upward, preheating the siderite in the shaft furnace above it.

[0056] S6: The decomposed iron ore is cooled to 250 - 300 °C through the first slow cooling shaft furnace 6, the second slow cooling shaft furnace 7, and the third slow cooling shaft furnace 8, and then discharged into the water in the water quenching tank 10 by the toothed roll discharger 901 for anaerobic water quenching. The water-quenched iron ore is scraped out of the water quenching tank 10 by the scale board machine 14, then ball-milled by the ball mill 15, and then the Fe 3 O 4Select;

[0057] S7: The generated flue gas is cooled to below 100°C after heat exchange in the first heat exchanger 17, the second heat exchanger 18, and the third heat exchanger 19, and then the particulate matter is removed by the dust collector 20, and then the SO in the flue gas is removed by the desulfurization tower 21. 2 , and finally it is blown into the chimney 23 by the induced draft fan 22 and discharged up to the standard.

[0058] The working principle of the present invention is as follows: When the combustion-supporting fan 11, the first blower 12, and the second blower 13 are turned on, negative pressures will be generated at the air inlets of the three, and the air from the outside will be extracted through the pipelines respectively, that is, the ambient normal-temperature air will enter the first heat exchanger 601 of the first slow-cooling shaft furnace 6, the second heat exchanger 701 of the second slow-cooling shaft furnace 7, and the third heat exchanger 801 of the third slow-cooling shaft furnace 8 through the first heat exchanger 17, the second heat exchanger 18, and the third heat exchanger 19 respectively. After the air in the corresponding pipelines is heated to 500 - 550°C, 400 - 450°C, and 300 - 350°C in the first heat exchanger 601, the second heat exchanger 701, and the third heat exchanger 801 respectively, it is blown into the next stage by the corresponding combustion-supporting fan 11, the first blower 12, and the second blower 13;

[0059] The combustion-supporting fan 11 blows the heated gas into the air guiding wall 501 in the microwave magnetization roasting shaft furnace 5 and the third air cap 401 in the exothermic oxidation shaft furnace 4 through the pipeline, and uniformly heats the materials in the microwave magnetization roasting shaft furnace 5 and the exothermic oxidation shaft furnace 4. Similarly, the first blower 12 and the second blower 13 respectively heat the materials in the preheating shaft furnace 3 and the drying shaft furnace 2 through the hot air entering the second air cap 301 and the first air cap 203 respectively;

[0060] During this process, due to the large mass and density of the siderite and the additive, they will continuously fall downward to the lower shaft furnace after continuous heating, while the density of the heated gas is less than that of the ambient normal-temperature air. With the assistance of the fan, it finally discharges from the exhaust port 201 of the drying shaft furnace 2. After the discharged hot air is sucked by the negative pressure of the combustion-supporting fan 11, the first blower 12, and the second blower 13 and guided by the pipeline, it passes through the first heat exchanger 17, the second heat exchanger 18, and the third heat exchanger 19 in sequence, and preliminarily heats the ambient normal-temperature air inside. Finally, the air temperature in the pipeline between the first heat exchanger 17 and the first slow-cooling shaft furnace 6 is 110 - 120°C, the air temperature in the pipeline between the second heat exchanger 18 and the second slow-cooling shaft furnace 7 is 80 - 90°C, and the air temperature in the pipeline between the third heat exchanger 19 and the third slow-cooling shaft furnace 8 is 50 - 60°C, respectively reducing the energy consumption for heating the first heat exchanger 17, the second heat exchanger 18, and the third heat exchanger 19 to the corresponding temperatures;

[0061] Meanwhile, during the heating process of the microwave magnetization roasting shaft furnace 5 by the microwave heater 502, the hot gas generated by the exothermic oxidation of CO in the air guiding wall 501 will move upward, and the additive undergoes an oxidation reaction to release a large amount of heat, further providing heat to the shaft furnace above it, comprehensively utilizing the thermal energy, greatly saving energy consumption. Through testing by those skilled in the art, the energy consumption per ton of processing is reduced to less than 100 degrees of electricity, significantly reducing the production cost. Moreover, microwave-assisted catalytic heating is adopted, and the magnetization roasting effect is good. The iron grade of siderite is increased from 40 - 43% to 62 - 65%, greatly accelerating the decomposition time of siderite and improving the production capacity. At the same time, during the production process, straw, wheat straw, biochemical sludge, etc. are fully utilized as fuels, making contributions to the comprehensive utilization of resources;

[0062] The decomposed iron ore is cooled to 250 - 300 °C by the first slow cooling shaft furnace 6, the second slow cooling shaft furnace 7, and the third slow cooling shaft furnace 8, and then discharged into the water in the water quenching tank 10 by the toothed roll unloader 901 for anaerobic water quenching. The water-quenched iron ore is scraped out of the water quenching tank 10 by the scaleboard machine 14, then ball-milled by the ball mill 15, and then the Fe 3 O 4 is separated by the magnetic separator 16;

[0063] The generated flue gas is cooled to below 100 °C after heat exchange in the first heat exchanger 17, the second heat exchanger 18, and the third heat exchanger 19, then the particulate matter is removed by the dust collector 20, and then the SO 2 in the flue gas is removed by the desulfurization tower 21, and finally, it is blown into the chimney 23 by the induced draft fan 22 and discharged up to the standard.

[0064] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0065] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A microwave magnetization roasting device for siderite, comprising a feeding belt conveyor (1), a microwave magnetization roasting vertical furnace (5) and a desulfurization tower (21), wherein the microwave magnetization roasting vertical furnace (5) is connected to an oxidation exothermic vertical furnace (4) at its top, the oxidation exothermic vertical furnace (4) is connected to a preheating vertical furnace (3) at its top, the preheating vertical furnace (3) is connected to a drying vertical furnace (2) at its top, the drying vertical furnace (2) is connected to the feeding belt conveyor (1) and is used for preliminarily drying the siderite conveyed by the feeding belt conveyor (1), characterized in that: It also includes a first slow cooling vertical furnace (6) connected to the bottom end of the microwave magnetization vertical furnace, the bottom end of the first slow cooling vertical furnace (6) is connected to a second slow cooling vertical furnace (7), the top end of the second slow cooling vertical furnace (7) is connected to the first slow cooling vertical furnace (6), and the bottom end is connected to a third slow cooling vertical furnace (8), the top end of the third slow cooling vertical furnace (8) is connected to the bottom end of the second slow cooling vertical furnace (7), and the bottom end is connected to a discharge vertical furnace (9), the top end of the discharge vertical furnace (9) is connected to the bottom end of the third slow cooling vertical furnace (8), and the distribution state is: the drying vertical furnace (2), the preheating vertical furnace (3), the oxidation exothermic vertical furnace (4), the microwave magnetization roasting vertical furnace (5), the first slow cooling vertical furnace (6), the second slow cooling vertical furnace (7), the third slow cooling vertical furnace (8), and the discharge vertical furnace (9) are connected in series and sealed from top to bottom, and the siderite moves from top to bottom by gravity; It also includes a waste heat transfer mechanism, which utilizes the heat energy in the components connected thereto to perform corresponding thermal processing on the siderite, including a first heat exchanger (601), a second heat exchanger (701), and a third heat exchanger (801) respectively arranged in the first slow cooling vertical furnace (6), the second slow cooling vertical furnace (7), and the third slow cooling vertical furnace (8); It also includes a first heat exchanger (17), a second heat exchanger (18), and a third heat exchanger (19) arranged on one side of the first slow cooling vertical furnace (6), the second slow cooling vertical furnace (7), and the third slow cooling vertical furnace (8); the first heat exchanger (17), the second heat exchanger (18), and the third heat exchanger (19) are respectively connected to one side of the first heat exchanger (601), the second heat exchanger (701), and the third heat exchanger (801) through pipelines, and the three are interconnected and distributed in a straight line; the exhaust port (201) on the drying vertical furnace (2) is connected to the inlet end of the first heat exchanger (17), and the outlet end of the third heat exchanger (19) is connected to the desulfurization tower (21); The invention also comprises a combustion-supporting fan (11), a first blower (12), and a second blower (13); the air inlets of the combustion-supporting fan (11), the first blower (12), and the second blower (13) are respectively connected to the first heat exchanger (601), the second heat exchanger (701), and the third heat exchanger (801); the air outlet of the combustion-supporting fan (11) is respectively connected to the air guide wall (501) in the microwave magnetization roasting vertical furnace (5) and the third air hood (401) in the oxidation exothermic vertical furnace (4) through a pipeline; the air outlets of the first blower (12) and the second blower (13) are respectively connected to the second air hood (301) in the preheating vertical furnace (3) and the first air hood (203) in the drying vertical furnace (2).

2. The microwave magnetization roasting device for siderite according to claim 1, characterized in that: The microwave magnetization roasting vertical furnace (5) is provided with an air guide wall (501), and a microwave heater (502) is provided on the outer wall. The air guide wall (501) is evenly arranged with air holes. The microwave heater (502) provides microwave energy for the microwave magnetization roasting vertical furnace (5). The microwave energy evenly heats the siderite and catalyzes a decomposition reaction.

3. The microwave magnetization roasting device for siderite according to claim 2, characterized in that: An exhaust port (201) is provided at the top of the drying vertical furnace (2), a feed port (202) is provided on the drying vertical furnace (2), the feed port (202) is located at the discharge end of the feed belt conveyor (1), and a first air hood (203) is provided in the drying vertical furnace (2), the first air hood (203) evenly disperses the hot air in the drying vertical furnace (2).

4. The microwave magnetization roasting device for siderite according to claim 3, characterized in that: The preheating vertical furnace (3) is provided with a second hood (301), which has the function of evenly dispersing hot air. This part of the hot air comes from the second slow cooling vertical furnace (7) and is used to preheat the mixture of siderite and additives in this section.

5. The microwave magnetization roasting device for siderite according to claim 4, characterized in that: The oxidation exothermic vertical furnace (4) is provided with a third hood (401), and the third hood (401) has the function of evenly dispersing hot air. This portion of hot air comes from the first slow cooling vertical furnace (6), and the additive is burned and released in this section to heat the siderite.

6. The microwave magnetization roasting device for siderite according to claim 5, characterized in that: The bottom end of the discharge vertical furnace (9) is connected to a water quenching tank (10), and a heat exchange coil (1001) is arranged in the water quenching tank (10).

7. The microwave magnetization roasting device for siderite according to claim 6, characterized in that: The water quenching tank (10) is provided with a finished product processing mechanism, which performs ball milling and screening on the preliminarily processed siderite to convert it into iron concentrate, and comprises a toothed roller discharger (901) arranged in a discharge shaft furnace (9), and also comprises a scale plate machine (14) arranged in the water quenching tank (10), wherein the end of the scale plate machine (14) is connected to a ball mill (15), and a magnetic separator (16) is arranged at the discharge port of the ball mill (15).

8. The microwave magnetization roasting device for siderite according to claim 7, characterized in that: A dust collector (20) is provided between the desulfurization tower (21) and the third heat exchanger (19); the inlet of the dust collector (20) is connected to the outlet of the third heat exchanger (19), and the outlet is connected to the inlet of the desulfurization tower (21).

9. The microwave magnetization roasting device for siderite according to claim 8, characterized in that: An induced draft fan (22) is provided at the top of the desulfurization tower (21), and a chimney (23) is provided on the induced draft fan (22).

10. A roasting method, characterized in that: The roasting method applicable to the microwave magnetization roasting device of siderite as described in claim 9 above comprises the following steps: S1: firstly crush the siderite into small pieces of 10-30 mm, and then feed the additive and the crushed siderite into a feed belt conveyor (1) in proportion. Then, after being transmitted by the feed belt conveyor (1), the siderite enters a drying vertical furnace (2). The mass ratio of the siderite to the additive is 10:0.5 to 10:

1. The additive is straw and dried biochemical sludge. The additive is a solid with a certain calorific value and a low ignition point. S2: The siderite is dried in the drying vertical furnace (2) at a drying temperature of 100-150°C. The heat comes from two parts: one part is the hot air moving upward in the preheating vertical furnace (3); the other part is the room temperature air heated to 50-60°C by the third heat exchanger (19), then heated to 300-350°C by the third heat exchanger (801), and then blown into the first air hood (203) by the second blower (13) and evenly dispersed; S3: The siderite is preheated to above 300°C in the preheating vertical furnace (3). The heat comes from two parts: one part is the hot air moving upward in the oxidation exothermic vertical furnace (4); the other part is the room temperature air heated to 80-90°C by the second heat exchanger (18), and then heated to 400-450°C by the second heat exchanger (701), and then blown into the second hood (301) by the first blower (12) and evenly dispersed; S4: The siderite is preheated to above 450°C in the oxidation exothermic vertical furnace (4). The heat comes from four parts: the first part is the hot air moving upward in the microwave magnetization roasting vertical furnace (5); the second part is the hot air generated by the CO oxidation exothermic in the air guide wall (501) moving upward; the third part is the oxidation reaction of the additives to release a large amount of heat; the fourth part is the room temperature air heated to 110-120°C by the first heat exchanger (17), and then heated to 500-550°C by the first heat exchanger (601), and then blown into the third air hood (401) by the combustion-supporting fan (11) and evenly dispersed; S5: the siderite is catalyzed by microwaves and heated to 600-700°C in the microwave magnetization roasting vertical furnace (5), the siderite is rapidly decomposed, and the generated CO and CO2 gases penetrate into the air guide wall (501), wherein the CO gas undergoes an oxidation reaction in the air guide wall (501), releases heat and moves upward, preheating the siderite in the vertical furnace above it; S6: the decomposed iron ore is cooled to 250-300°C in a first slow cooling vertical furnace (6), a second slow cooling vertical furnace (7), and a third slow cooling vertical furnace (8), and then discharged into water in a water quenching tank (10) by a toothed roller unloader (901) for oxygen-free water quenching. The quenched iron ore is scraped out of the water quenching tank (10) by a scale plate machine (14), and then ball milled in a ball mill (15), and then Fe3O4 is separated by a magnetic separator (16); S7: The generated flue gas is cooled to below 100°C after heat exchange in the first heat exchanger (17), the second heat exchanger (18), and the third heat exchanger (19). The flue gas is then passed through a dust collector (20) to remove particulate matter. The flue gas is then passed through a desulfurization tower (21) to remove SO2 from the flue gas. The flue gas is finally blown into a chimney (23) by an induced draft fan (22) to meet emission standards.

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