A system and method for high-temperature rapid fluidization magnetization roasting of ilmenite

Abstract

The present invention relates to the field of pretreatment and quality improvement of ore by roasting process, and specifically to a high-temperature rapid fluidized magnetized roasting system and method for ilmenite, the system comprising a feed bin, a dryer, a cyclone preheater, a fluidized roasting furnace, a fluidized cooling bed, and a discharge bin. The method is as follows: the ore powder is dehydrated from the feed bin through the dryer; the dried ore is preheated and heated by the cyclone preheater; the hot ore powder is subjected to high-temperature rapid fluidized oxidation magnetized roasting; the hot roasted ore is cooled by air fluidization and then sent to magnetic separation. The present invention has the advantages of high-temperature rapid oxidation of ilmenite, coordinated regulation of the terminal oxidation degree of the roasted ilmenite during the low-temperature cooling process, efficient utilization of the sensible heat of the roasted ore, and low system energy consumption, and can achieve the goal of efficient separation and utilization of ilmenite for quality improvement and impurity removal.

Description

Technical Field

[0001] The present invention belongs to the field of mineral processing and metallurgical joint process, and is used for pretreatment and quality improvement of ilmenite raw material minerals for the production of titanium-iron symbiotic metal element products, and particularly relates to pretreatment and quality improvement of ore by using a roasting process, and specifically relates to a high-temperature rapid fluidized magnetization roasting system and method for ilmenite. Background Art

[0002] Chinese patent application CN 106861892A discloses a separation device scheme containing chromite and ilmenite ores. The device includes a roasting system arrangement including a roasting furnace, a cyclone, a fluidized bed cooler, etc. However, the hot ilmenite roasted ore is cooled down by sending it out of the roasting system in the form of hot water through a heat exchange component. This part of the heat cannot be used in the roasting system, and the system energy consumption can be further reduced. At the same time, the patented oxidation roasting time is 30-180 seconds. The oxidation transformation of ilmenite (FeTiO3) to ilmenite-hematite solid solution [xFeTiO3·(1-x)Fe2O3] is not a very fast reaction process, and ilmenite is easily oxidized above 800℃ to form weakly magnetic Fe2TiO5 (Fe2O3·TiO2) phase, which reduces the magnetic properties of the titanium-containing phase and further reduces the yield of the subsequent magnetic separation magnetic titanium-containing phase product. Therefore, a fluidized roasting system design with a wider process operation range and stronger adaptability is also needed to ensure that the divalent iron Fe in FeTiO3 in ilmenite is 2+ Fe 3+ Full and appropriate proportion conversion.

[0003] Therefore, there is a need in the art for a high-efficiency, low-consumption, high-temperature, rapid fluidized magnetized roasting system and method for ilmenite based on the principle advantages of a fluidized bed reactor and targeting the oxidation roasting reaction characteristics of ilmenite. Summary of the invention

[0004] The purpose of the present invention is to provide a high-temperature rapid fluidized magnetized roasting system and method for ilmenite, which can realize efficient oxidation regulation of low-grade ilmenite through high-temperature rapid and low-temperature cooling fluidized oxidation magnetized roasting, and optimize the energy migration utilization in the system, so as to ultimately achieve efficient and low-consumption comprehensive utilization of low-grade ilmenite resources.

[0005] The present invention provides a high-temperature rapid fluidized magnetized roasting system for ilmenite, comprising a feed bin, a dryer, a cyclone preheater, a fluidized roasting furnace, a fluidized cooling bed, and a discharge bin;

[0006] The dryer includes a venturi airflow dryer 2, a drying cyclone separator 3 and a bag dust collector 4; the cyclone preheater includes a multi-stage preheating cyclone and a preheating burner 9; the fluidized roasting furnace includes a roasting furnace body 7 and a roasting cyclone separator 8; the fluidized cooling bed includes a cooling bed body 10 and a cooling cyclone separator 11; wherein,

[0007] The discharge port of the feed bin 1 is connected to the feed port of the venturi airflow dryer 2, the top air outlet of the venturi airflow dryer 2 is connected to the air inlet of the drying cyclone separator 3, the top air outlet of the drying cyclone separator 3 is connected to the air inlet of the bag dust collector 4, the lower discharge port of the drying cyclone separator 3 and the lower return port of the bag dust collector 4 are both connected to the air inlet of the highest level preheating cyclone, and the bottom air inlet of the venturi airflow dryer 2 is respectively connected to the air pipeline and the top air outlet of the highest level preheating cyclone;

[0008] The air inlet of the highest level preheating cyclone is connected to the lower discharge port of the drying cyclone separator 3 and the lower return port of the bag dust collector 4 at the same time, the top air outlet of the highest level preheating cyclone is connected to the bottom air inlet of the venturi airflow dryer 2, the air inlet of the lowest level preheating cyclone in the multi-stage preheating cyclone is connected to the air outlet of the preheating burner 9, the air inlet of the preheating burner 9 is respectively connected to the fuel pipeline and the top air outlet of the roasting cyclone separator 8, and the lower discharge port of the lowest level preheating cyclone is connected to the feed port of the roasting furnace body 7;

[0009] The feed inlet of the roasting furnace body 7 is connected to the lower discharge port of the lowest level preheating cyclone, the top air outlet of the roasting furnace body 7 is connected to the air inlet of the roasting cyclone separator 8, the top air outlet of the roasting cyclone separator 8 is connected to the air inlet of the preheating burner 12, the bottom discharge port of the roasting cyclone separator 8 is connected to the return port of the roasting furnace body 7, the bottom air inlet of the roasting furnace body 7 is connected to the top air outlet of the cooling cyclone separator 11, and the discharge port of the roasting furnace body 7 is connected to the feed port of the cooling bed body 10;

[0010] The feed port of the cooling bed body 10 is connected to the discharge port of the roasting furnace body 7, the top air outlet of the cooling bed body 10 is connected to the air inlet of the cooling cyclone separator 11, the top air outlet of the cooling cyclone separator 11 is connected to the air inlet of the roasting furnace body 7, the bottom discharge port of the cooling cyclone separator 8 and the discharge port of the cooling bed body 10 are connected to the feed port of the discharge bin 11, and the bottom air inlet of the cooling bed body 10 is connected to the air pipeline.

[0011] Preferably, the cyclone preheater comprises multiple stages of preheating cyclones, and the preheating cyclones at each stage are sequentially connected in series;

[0012] In the multi-stage preheating cyclone, when the number of stages is two, the lower discharge port of the first-stage preheating cyclone 5 is connected to the air inlet of the second-stage preheating cyclone 6, and the top air outlet of the second-stage preheating cyclone 6 is connected to the air inlet of the first-stage preheating cyclone 5.

[0013] When the number of stages is two or more, the air inlet of the highest stage preheating cyclone is simultaneously connected to the lower discharge port of the drying cyclone separator 3 and the lower return port of the bag dust collector 4;

[0014] The top air outlet of the highest level preheating cyclone is connected to the bottom air inlet of the Venturi airflow dryer 2;

[0015] The air inlet of the lowest level preheating cyclone is connected to the air outlet of the preheating burner 9;

[0016] The lower discharge port of the lowest level preheating cyclone is connected to the feed port of the roasting furnace body 7;

[0017] The lower discharge port of the higher-level preheating cyclone is connected to the air inlet of the lower-level preheating cyclone, and the top air outlet of the lower-level preheating cyclone is connected to the air inlet of the higher-level preheating cyclone.

[0018] It should be noted that in a multi-stage preheating cyclone, when there are two stages, the highest level preheating cyclone is the first level preheating cyclone, and the lowest level preheating cyclone is the second level preheating cyclone; when there are more than two stages, the highest level preheating cyclone is the first level preheating cyclone, for example, the first level is a higher level preheating cyclone than the second level, and the second level is a lower level preheating cyclone than the first level. It is further explained that the level in the multi-stage preheating cyclone generally refers to the height of the position where the preheating cyclone is set, for example, the setting position of the first level preheating cyclone is higher than the setting position of the second level preheating cyclone, the highest level preheating cyclone is the preheating cyclone with the highest position in the multi-stage preheating cyclone, and the lowest level preheating cyclone is the preheating cyclone with the lowest setting position.

[0019] Preferably, the bottom discharge port of the roasting cyclone separator 8 and the discharge port of the roasting furnace body 7 are located on different sides, and the roasting furnace is a turbulent fluidized bed.

[0020] Preferably, the cooling bed body 10 is a bubbling or turbulent fluidized bed.

[0021] The present invention also provides a high-temperature rapid fluidized magnetization roasting method for ilmenite based on the above system, the method comprising:

[0022] The ilmenite powder stored in the feed bin enters the Venturi airflow dryer and is dehydrated and dried by the hot flue gas, and then is separated from the gas and solid by the drying cyclone separator. The dried ore powder after gas-solid separation and the dried ore powder collected by the bag dust collector enter the cyclone preheater together. In the multi-stage preheating cyclone, the ore powder and the hot flue gas after the hot tail gas of the roasting furnace are subjected to gas-solid countercurrent heat exchange and temperature rise. The heated hot ore powder enters the roasting furnace body and undergoes high-temperature rapid oxidation magnetization roasting reaction of ilmenite with the hot air. The hot roasted ore powder entrained by the airflow is separated from the gas and solid by the roasting cyclone separator and then returns to the roasting furnace body. The hot roasted ore powder enters the cooling bed body from the roasting furnace body discharge port. In the cooling fluidized bed, the hot roasted ore powder and the room temperature air are subjected to gas-solid countercurrent heat exchange and low-temperature oxidation, and finally enter the discharge bin for storage. The cooled roasted ore powder entrained by the airflow is directly stored in the discharge bin after gas-solid separation by the cooling cyclone separator.

[0023] Room temperature air enters from the bottom of the cooling bed body and undergoes gas-solid heat exchange with the hot roasted ore powder in the cooling bed body to cool down and undergo low-temperature oxidation. The air after heat exchange is discharged through the top outlet of the cooling cyclone separator and enters the roasting furnace body to undergo high-temperature rapid oxidation magnetization roasting with the ilmenite ore powder. The hot exhaust gas after the reaction is separated from the gas and solid by the roasting cyclone separator and enters the preheating burner. After heating with the fuel combustion, it enters the cyclone preheater and undergoes gas-solid countercurrent heat exchange with the dry ore powder. The exhaust gas after heat exchange is mixed with room temperature air and then passes through a Venturi airflow dryer to dry the wet ilmenite ore powder, and then passes through a drying cyclone separator and a bag dust collector for separation and purification before being discharged.

[0024] Preferably, the particle size of the ilmenite powder is in the range of 0.005-9 mm, the TiO2 content is in the range of 10-47 wt %, the water content is less than 15 wt %, and the titanium and iron elements are mainly present in the ilmenite phase FeTiO3.

[0025] Preferably, the temperature of the fluidized calcining furnace is 800-1100°C, such as 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C and the range between any two of the above data; the high-temperature oxidation roasting time is 0.5-30 minutes, such as 0.5 minutes, 4 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes and the range between any two of the above data; the temperature of the fluidized cooling furnace is not higher than 800°C, and the cooling time is 1-30 minutes, such as 1 minute, 4 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes and the range between any two of the above data.

[0026] Preferably, after the ilmenite powder is subjected to high-temperature rapid oxidation roasting in a fluidized roasting furnace and low-temperature supplementary oxidation in a fluidized cooling bed, the divalent iron Fe in the ilmenite phase FeTiO3 in the original ore is 2+ Fe 3+The conversion ratio ranges from 10-90%, such as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and ranges between any two of the above data. The "%" here has no unit.

[0027] Preferably, the fuel is one or at least two of fuel oil, coal, fuel gas, and coal gas having combustion calorific value.

[0028] Preferably, the temperature of the air outlet of the drying cyclone separator 3 is not lower than 100°C, the final cooling temperature of the roasted ore powder entering the discharge bin is lower than 100°C, and the temperature of the air entering the cooling bed body is not higher than 100°C.

[0029] Compared with the existing ilmenite oxidation magnetization roasting system and method, the characteristics and advantages of the present invention are:

[0030] (1) High-temperature rapid oxidation magnetization roasting is carried out in the temperature range of 800-1100°C, and an air-cooled fluidized bed is set up. During cooling, the high-temperature waste heat of the roasted ore is used for low-temperature supplementary oxidation to adjust the oxidation degree. This not only takes advantage of the rapid reaction of high-temperature oxidation and reduces the overall oxidation roasting time, but also avoids the problem that ilmenite is easily oxidized for a long time at a temperature above 800°C to generate weakly magnetic Fe2TiO5 (Fe2O3·TiO2) phases that reduce the magnetic properties of the titanium-containing phase, thereby reducing the yield of the subsequent magnetic separation magnetic titanium-containing phase product;

[0031] (2) The reaction residence time of the non-fast conveying bed is adjustable, and the turbulent fluidized bed and the cyclone separation of the oxidation tail gas of the roasting furnace are used to return the material, which ensures that the coarse-grained ilmenite particles have sufficient residence time in the furnace for slow oxidation reaction and the fluidized gas to quickly carry out the fine-grained ilmenite particles, resulting in a high magnetic phase conversion rate and strong adaptability to incoming materials;

[0032] (3) Fluidized cooling bed air cooling is used to preheat the oxidation raw gas for hot roasting ore, and the roasting furnace hot oxidation exhaust gas is burned to preheat the cold ore. Venturi air flow dryer and room temperature air mixing are arranged to achieve the cooling-preheating-drying migration utilization of energy in the system. A good heat-temperature balance can be achieved by adjusting fuel replenishment and room temperature air mixing, thereby optimizing and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the system configuration of the high-temperature fluidized magnetized roasting of ilmenite according to the present invention.

[0034] Reference numerals:

[0035] 1. Feed bin; 2. Venturi airflow dryer; 3. Drying cyclone separator; 4. Bag dust collector; 5. First-stage preheating cyclone; 6. Second-stage preheating cyclone; 7. Roasting furnace body; 8. Roasting cyclone separator; 9. Preheating burner; 10. Cooling bed body; 11. Cooling cyclone separator; 12. Discharge bin. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific embodiments.

[0037] Example 1

[0038] like Figure 1 As shown, a high-temperature fluidized magnetized roasting system for ilmenite includes a feed bin, a dryer, a cyclone preheater, a fluidized roasting furnace, a fluidized cooling bed, and a discharge bin;

[0039] The dryer includes a venturi airflow dryer 2, a drying cyclone separator 3 and a bag dust collector 4; the cyclone preheater includes a two-stage preheating cyclone and a preheating combustion 9; the fluidized roasting furnace includes a roasting furnace body 7 and a roasting cyclone separator 8; the fluidized cooling bed includes a cooling bed body 10 and a cooling cyclone separator 11; wherein,

[0040] The discharge port of the feed bin 1 is connected to the feed port of the venturi airflow dryer 2, the top air outlet of the venturi airflow dryer 2 is connected to the air inlet of the drying cyclone separator 3, the top air outlet of the drying cyclone separator 3 is connected to the air inlet of the bag dust collector 4, the lower discharge port of the drying cyclone separator 3 and the lower return port of the bag dust collector 4 are both connected to the air inlet of the primary preheating cyclone 5, and the bottom air inlet of the venturi airflow dryer 2 is respectively connected to the air pipeline and the top air outlet of the primary preheating cyclone 5;

[0041] The air inlet of the first-stage preheating cyclone 5 is connected to the lower discharge port of the drying cyclone separator 3 and the lower return port of the bag dust collector 4 at the same time, the top air outlet of the first-stage preheating cyclone 5 is connected to the bottom air inlet of the venturi airflow dryer 2, the air inlet of the second-stage preheating cyclone 6 and the lower discharge port of the first-stage preheating cyclone 5 are connected to the air outlet of the preheating burner 9, the air inlet of the preheating burner 9 is respectively connected to the fuel pipeline and the top air outlet of the roasting cyclone separator 8, and the lower discharge port of the second-stage preheating cyclone 6 is connected to the feed port of the roasting furnace body 7;

[0042] The feed inlet of the roasting furnace body 7 is connected to the lower discharge port of the secondary preheating cyclone 6, the top air outlet of the roasting furnace body 7 is connected to the air inlet of the roasting cyclone separator 8, the top air outlet of the roasting cyclone separator 8 is connected to the air inlet of the preheating burner 12, the bottom discharge port of the roasting cyclone separator 8 is connected to the return port of the roasting furnace body 7, the bottom air inlet of the roasting furnace body 7 is connected to the top air outlet of the cooling cyclone separator 11, and the discharge port of the roasting furnace body 7 is connected to the feed port of the cooling bed body 10;

[0043] The feed port of the cooling bed body 10 is connected to the discharge port of the roasting furnace body 7, the top air outlet of the cooling bed body 10 is connected to the air inlet of the cooling cyclone separator 11, the top air outlet of the cooling cyclone separator 11 is connected to the air inlet of the roasting furnace body 7, the bottom discharge port of the cooling cyclone separator 8 and the discharge port of the cooling bed body 10 are connected to the feed port of the discharge bin 11, and the bottom air inlet of the cooling bed body 10 is connected to the air pipeline.

[0044] The bottom discharge port of the roasting cyclone separator 8 and the discharge port of the roasting furnace body 7 are located on different sides, that is, the bottom discharge port of the roasting cyclone separator 8 is not directly connected to the discharge port of the roasting furnace body 7, and the roasting furnace is a turbulent fluidized bed. The cooling bed body 10 is a bubbling or turbulent fluidized bed.

[0045] To further explain, if the shape of the roasting furnace body 7 is a cube, the bottom discharge port of the roasting cyclone separator 8 and the discharge port of the roasting furnace body 7 are located on different sides; if the shape of the roasting furnace body 7 is a cylinder, the bottom discharge port of the roasting cyclone separator 8 and the discharge port of the roasting furnace body 7 are located on the outer side of the cylinder, and the center angle between the bottom discharge port of the roasting cyclone separator 8 and the discharge port of the roasting furnace body 7 is greater than 45 degrees.

[0046] In this embodiment, the number of preheating cyclones can be changed as needed, and the structure listed here is only a better implementation of the present invention.

[0047] Example 2

[0048] The method for fluidized oxidation magnetization roasting of ilmenite using the above-mentioned high-temperature rapid fluidized roasting system of ilmenite is as follows:

[0049] The ilmenite powder is stored in the feed bin and enters the Venturi airflow dryer to be dehydrated and dried by the hot flue gas, and then separated by gas and solid in the drying cyclone separator. The dried ore powder after gas-solid separation and the dried ore powder collected by the bag dust collector enter the cyclone preheater together. In the multi-stage preheating cyclone, the ore powder and the hot flue gas after the hot tail gas of the roasting furnace are subjected to gas-solid countercurrent heat exchange and temperature rise. The heated hot ore powder enters the roasting furnace body and undergoes high-temperature rapid oxidation magnetization roasting reaction of ilmenite with the hot air. The hot roasted ore powder entrained by the airflow is separated by gas and solid in the roasting cyclone separator and then returns to the roasting furnace body. The hot roasted ore powder enters the cooling bed body from the roasting furnace body discharge port. In the fluidized cooling bed, the hot roasted ore powder and the room temperature air are subjected to gas-solid countercurrent heat exchange and low-temperature oxidation, and finally enter the discharge bin for storage. The cooled roasted ore powder entrained by the airflow is directly stored in the discharge bin after gas-solid separation in the cooling cyclone separator.

[0050] Room temperature air enters from the bottom of the cooling bed body and undergoes gas-solid heat exchange and low-temperature oxidation with the hot roasting powder in the cooling bed body. The air after heat exchange is discharged through the top outlet of the cooling cyclone separator and enters the roasting furnace body to undergo high-temperature rapid oxidation magnetization roasting with the ilmenite powder. The hot exhaust gas after the reaction is separated from the gas and solid by the roasting cyclone separator and enters the preheating burner. After heating with the fuel combustion, it enters the cyclone preheater and undergoes gas-solid countercurrent heat exchange with the dry ore powder. The exhaust gas after heat exchange is mixed with room temperature air and then passes through a Venturi airflow dryer to dry the wet ilmenite powder, and then passes through a drying cyclone separator and a bag dust collector for separation and purification before being discharged.

[0051] Example 3

[0052] The titanium grade treated by the present invention has a TiO2 content of 39 wt %, a particle size of 0.03-1 mm, of which 40% are particles less than 0.074 mm. The titanium and iron elements in the ore powder exist in the form of ilmenite phase FeTiO3, and the free water content is 11 wt %.

[0053] First, the ilmenite powder is sent from the feed bin to the Venturi airflow dryer to be dehydrated and dried by hot flue gas. The temperature of the hot flue gas exhaust after drying is 109℃, and the free water content of the powder after dehydration is <1 wt%. The powder is then heated by heat exchange with the exhaust gas of the fluidized bed after combustion in the three-stage cyclone preheater, and then enters the turbulent fluidized bed for oxidative magnetization roasting with preheated air at 810℃ for 10 minutes. The divalent iron Fe in the FeTiO3 phase of the ilmenite in the original ore is 2+ Fe 3+ The conversion ratio is 35%. The hot roasted ore is directly cooled to 90℃ by heat exchange in the air fluidized cooling bed and enters the discharge ore bin. The cooling and low-temperature oxidation time in the air fluidized cooling furnace is 5 minutes and the average temperature is 350℃. At this time, the divalent iron Fe in the ilmenite phase FeTiO3 in the original ore is 2+ Fe 3+The conversion ratio is increased to 41%. The air after heat exchange with the hot roasted ore in the fluidized cooling furnace is sent into the roasting fluidized bed as oxidizing gas to undergo high-temperature rapid oxidation reaction with ilmenite powder. The fuel of the preheating burner is natural gas, with a methane CH4 volume content of 93%.

[0054] The cooling roasted ore was tested by 3500 Oe weak magnetic separation after grinding and mineral phase separation, and a titanium concentrate powder product with a titanium grade TiO2 content of 48.7 wt% and a titanium element recovery rate of 92.0% was obtained. This is a good indicator.

[0055] Example 4

[0056] The titanium grade treated by the present invention has a TiO2 content of 29 wt %, a particle size of 0.1-3 mm, of which the particle size less than 1 mm accounts for 50%. The titanium and iron elements in the ore powder exist in the form of ilmenite phase FeTiO3, and the free water content is 5 wt %.

[0057] First, the ilmenite powder is sent from the feed bin to the Venturi airflow dryer to be dehydrated and dried by hot flue gas. The temperature of the hot flue gas exhaust after drying is 112℃, and the free water content of the powder after dehydration is <1 wt%. The powder is then heated by heat exchange with the exhaust gas of the fluidized bed after combustion in the four-stage cyclone preheater, and then enters the turbulent fluidized bed for oxidative magnetization roasting at 900℃ with the preheated air for 5 minutes. The divalent iron Fe in the FeTiO3 phase of the ilmenite in the original ore is 2+ Fe 3+ The conversion ratio is 55%. The hot roasted ore is directly cooled to 95℃ by heat exchange in the air fluidized cooling bed and enters the discharge ore bin. The cooling and low-temperature oxidation time in the air fluidized cooling furnace is 10 minutes and the average temperature is 390℃. At this time, the divalent iron Fe in the ilmenite phase FeTiO3 in the original ore is 2+ Fe 3+ The conversion ratio is increased to 58%. The air after heat exchange with the hot roasted ore in the fluidized cooling furnace is sent into the roasting fluidized bed as oxidizing gas to undergo high-temperature rapid oxidation reaction with ilmenite powder. The fuel of the preheating burner is pulverized coal, and the calorific value of pulverized coal is 5000 kcal / kg.

[0058] The cooling roasted ore was tested by 3400 Oe weak magnetic separation after grinding and mineral phase separation, and a titanium concentrate powder product with a titanium grade TiO2 content of 47.2 wt% and a titanium element recovery rate of 90.0% was obtained. This is a good indicator.

[0059] The process parameters (such as temperature, time, etc.) of the present invention can realize the method by taking upper and lower limits and interval values, and the embodiments are not listed one by one here.

[0060] Any contents not described in detail in the present invention can be based on the conventional technical knowledge in the art.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. A method for high-temperature rapid fluidized magnetized roasting of ilmenite, the system used in the method comprising a feed bin, a dryer, a cyclone preheater, a fluidized roasting furnace, a fluidized cooling bed, and a discharge bin; The dryer comprises a Venturi airflow dryer (2), a drying cyclone separator (3) and a bag dust collector (4); the cyclone preheater comprises a preheating burner (9) and a multi-stage preheating cyclone; the fluidized roasting furnace comprises a roasting furnace body (7) and a roasting cyclone separator (8); the fluidized cooling bed comprises a cooling bed body (10) and a cooling cyclone separator (11); wherein: The discharge port of the feed bin (1) is connected to the feed port of the venturi airflow dryer (2), the top air outlet of the venturi airflow dryer (2) is connected to the air inlet of the drying cyclone separator (3), the top air outlet of the drying cyclone separator (3) is connected to the air inlet of the bag dust collector (4), the lower discharge port of the drying cyclone separator (3) and the lower return port of the bag dust collector (4) are both connected to the air inlet of the highest level preheating cyclone, and the bottom air inlet of the venturi airflow dryer (2) is respectively connected to the air pipeline and the top air outlet of the highest level preheating cyclone; The air inlet of the lowest-stage preheating cyclone in the multi-stage preheating cyclone is connected to the air outlet of the preheating burner (9), the air inlet of the preheating burner (9) is respectively connected to the fuel pipeline and the top air outlet of the roasting cyclone separator (8), and the lower outlet of the lowest-stage preheating cyclone is connected to the feed inlet of the roasting furnace body (7); The top air outlet of the roasting furnace body (7) is connected to the air inlet of the roasting cyclone separator (8), the bottom discharge port of the roasting cyclone separator (8) is connected to the return port of the roasting furnace body (7), the bottom air inlet of the roasting furnace body (7) is connected to the top air outlet of the cooling cyclone separator (11), and the discharge port of the roasting furnace body (7) is connected to the feed port of the cooling bed body (10); The top air outlet of the cooling bed body (10) is connected to the air inlet of the cooling cyclone separator (11), the bottom discharge port of the cooling cyclone separator (11) and the discharge port of the cooling bed body (10) are connected to the feed port of the discharge bin (12), and the bottom air inlet of the cooling bed body (10) is connected to an air pipeline; The steps of the method include: The ilmenite powder stored in the feed bin enters the Venturi airflow dryer and is dehydrated and dried by the hot flue gas, and then is separated from the gas and solid by the drying cyclone separator. The dried ore powder after gas-solid separation and the dried ore powder collected by the bag dust collector enter the cyclone preheater together. In the multi-stage preheating cyclone, the ore powder and the hot flue gas after the hot tail gas of the roasting furnace are subjected to gas-solid countercurrent heat exchange and temperature rise. The heated hot ore powder enters the roasting furnace body and undergoes high-temperature rapid oxidation magnetization roasting reaction of ilmenite with the hot air. The hot roasted ore powder entrained by the airflow is separated from the gas and solid by the roasting cyclone separator and then returns to the roasting furnace body. The hot roasted ore powder enters the cooling bed body from the roasting furnace body discharge port. In the fluidized cooling bed, the hot roasted ore powder and the room temperature air are subjected to gas-solid countercurrent heat exchange and low-temperature oxidation, and finally enter the discharge bin for storage. The cooled roasted ore powder entrained by the airflow is directly stored in the discharge bin after gas-solid separation by the cooling cyclone separator. Room temperature air enters from the bottom of the cooling bed body and performs gas-solid heat exchange with the hot roasted ore powder to cool down and undergo low-temperature oxidation in the cooling bed body. The air after heat exchange is discharged through the air outlet at the top of the cooling cyclone separator and enters the roasting furnace body to perform high-temperature rapid oxidation magnetization roasting with the ilmenite ore powder. The hot tail gas after the reaction is separated from the gas and solid by the roasting cyclone separator and enters the preheating burner. After heating with the fuel combustion, it enters the cyclone preheater to perform gas-solid countercurrent heat exchange with the dry ore powder. The tail gas after heat exchange is mixed with room temperature air and then passes through the Venturi airflow dryer to dry the wet ilmenite ore powder, and then passes through the drying cyclone separator and bag dust collector in sequence for separation and purification before being discharged. The temperature of the fluidized bed roasting furnace is 800-1100°C, the high temperature oxidation roasting time is 0.5-30 minutes, the temperature of the fluidized bed cooling bed is not higher than 800°C, and the cooling time is 1-30 minutes; After the ilmenite powder is rapidly oxidized by a fluidized roaster at high temperature and supplemented by a fluidized cooling bed at low temperature, the divalent iron Fe in the ilmenite phase FeTiO3 in the original ore is 2+ Fe 3+ The conversion ratio ranges from 10-90%; The ilmenite powder has a particle size range of 0.005-9 mm, a TiO2 content range of 10-47 wt%, a water content of less than 15 wt%, and titanium and iron elements mainly exist in the ilmenite phase FeTiO3; High-temperature rapid oxidation magnetization roasting is carried out in the temperature range of 800-1100℃, and an air-cooled fluidized bed is set up. During cooling, the high-temperature waste heat of the roasted ore is used for low-temperature supplementary oxidation to adjust the degree of oxidation.

2. The method according to claim 1, characterized in that: The cyclone preheater comprises multiple stages of preheating cyclones, and the preheating cyclones at each stage are sequentially connected in series; When the number of stages is two, the lower outlet of the first-stage preheating cyclone (5) is connected to the air inlet of the second-stage preheating cyclone (6), and the top outlet of the second-stage preheating cyclone (6) is connected to the air inlet of the first-stage preheating cyclone (5); When the number of stages is two or more, the lower discharge port of the higher-level preheating cyclone is connected to the air inlet of the lower-level preheating cyclone, and the top air outlet of the lower-level preheating cyclone is connected to the air inlet of the higher-level preheating cyclone.

3. The method according to claim 1, characterized in that: The bottom discharge port of the roasting cyclone separator (8) and the discharge port of the roasting furnace body (7) are located on different sides, and the roasting furnace body (7) is a turbulent fluidized bed.

4. The method according to claim 1, characterized in that: The cooling bed body (10) is a bubbling or turbulent fluidized bed.

5. The method according to claim 1, characterized in that: The fuel is one or at least two of fuel oil, coal, fuel gas, and coal gas.

6. The method according to claim 1, characterized in that: The temperature of the air outlet of the drying cyclone separator (3) is not lower than 100°C, the final cooling temperature of the roasted ore powder entering the discharge bin is lower than 100°C, and the temperature of the air entering the cooling bed body is not higher than 100°C.

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