A spodumene ore powder suspension roasting furnace device and a roasting method

Abstract

A spodumene ore powder suspension roasting furnace device and a roasting method. The device includes a dispersion dryer, a first separator, a cyclone preheater, a suspension roasting furnace, a second separator, a phase change reactor, a cyclone cooler, a powder waste heat boiler, an exhaust gas purifier and a draft fan; a mineral powder feed port is provided on the dispersion dryer; the method is as follows: making spodumene original ore into mineral powder; continuously feeding it into the dispersion dryer; after dispersion drying, entering the first separator and the cyclone preheater; after heat exchange with hot gas, entering the suspension roasting furnace; heating to generate pre-phase change mineral powder, entering the second separator and the phase change reactor; introducing fluidizing air to generate full-phase change mineral powder; being sent into the cyclone cooler along with air; becoming pre-cooled mineral powder and entering the powder waste heat boiler; generating low-temperature mineral powder and discharging it. The process of the present invention is simple, the processing capacity of a single set of device is large, the floor area is small, and the construction investment is saved; the reaction speed is fast, the efficiency is high, the waste heat is fully utilized, the heat consumption is low, no waste residue is produced, the exhaust gas is concentrated and convenient to treat, and it is environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy manufacturing, and particularly relates to a spodumene ore powder suspension roasting furnace device and a roasting method. Background Art

[0002] Lithium is an important energy metal. According to statistics, the global lithium salt production capacity in 2020 was approximately 730,000 tons; with the rapid development of new energy vehicles and lithium batteries, it is extremely urgent to develop a new type of highly efficient, environmentally friendly, energy-saving spodumene ore powder roasting device.

[0003] Currently, in the process of producing lithium salts using spodumene as raw material, rotary kilns are mostly used for ore roasting equipment, and a few use tunnel kilns. When using a rotary kiln for production, it has high energy consumption, a large floor area, large investment, a large amount of slag discharge, and difficult pollutant treatment; when using a tunnel kiln for production, the process is complex, the efficiency is low, the degree of automation is poor, and the pollution is serious. Whether using a rotary kiln or a tunnel kiln to roast spodumene ore powder, the maximum annual processing capacity of a single set of equipment is 100,000 - 120,000 tons, and at the same time, it is required that the particle size of the spodumene ore powder is between 20 - 80 mm. Especially for the rotary kiln, since the temperature in the high-temperature zone is difficult to monitor, a large amount of caking occurs after the high-temperature roasting of the spodumene ore powder. Therefore, a grinding device must be added after roasting to reprocess the roasted material to meet the requirements of the leaching and lithium extraction process. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a spodumene ore powder suspension roasting furnace device and a roasting method.

[0005] The spodumene ore powder suspension roasting furnace device of the present invention includes a dispersion dryer 1, a first separator 2, a cyclone preheater 3, a suspension roasting furnace 4, a second separator 5, a phase change reactor 6, a cyclone cooler 7, a powder waste heat boiler 8, an exhaust gas purifier 9, and a draft fan 10; a mineral powder feed port is provided on the dispersion dryer 1; the air inlet of the dispersion dryer 1 is communicated with the outlet of the cyclone preheater 3 through a pipeline; the outlet of the dispersion dryer 1 is communicated with the inlet of the first separator 2; the outlet of the first separator 2 is communicated with the inlet of the cyclone preheater 3 through a feed pipeline; the outlet of the cyclone preheater 3 is communicated with the inlet of the suspension roasting furnace 4; the outlet of the suspension roasting furnace 4 is communicated with the inlet of the second separator 5; the outlet of the second separator 5 is communicated with the inlet of the phase change reactor 6; the outlet of the phase change reactor 6 is communicated with the inlet of the cyclone cooler 7 through a system air suction pipeline, and an air inlet is provided on the system air suction pipeline for sucking in air; the outlet of the cyclone cooler 7 is communicated with the inlet of the powder waste heat boiler 8; a fuel inlet is provided at the lower part of the suspension roasting furnace 4 for introducing fuel; a fluidizing air inlet is provided at the bottom of the phase change reactor 6 for introducing fluidizing air; the outlet of the first separator 2 is communicated with the inlet of the exhaust gas purifier 9; the outlet of the exhaust gas purifier 9 is communicated with the inlet of the draft fan 10; the outlet of the second separator 5 is communicated with the feed pipeline.

[0006] In the above device, a calcined material discharge port is provided at the bottom of the powder waste heat boiler 8.

[0007] In the above device, the powder waste heat boiler 8 is provided with a water inlet and a steam outlet which are communicated with the heat exchange pipes inside the powder waste heat boiler 8, or communicated with the cooling jacket of the powder waste heat boiler 8.

[0008] In the above device, the air outlet of the cyclone preheater 3 is communicated with the air inlet of the dispersion dryer 1.

[0009] In the above device, the air outlet of the cyclone cooler 7 is communicated with the air inlet at the bottom of the suspension roasting furnace 4.

[0010] In the above device, the waste gas purifier 9 is a bag filter or an electrostatic precipitator.

[0011] In the above device, the dispersion dryer 1 is a Venturi dryer, a flash dryer or a drying and dispersing machine.

[0012] The method for suspension roasting spodumene ore powder of the present invention adopts the above device and is carried out according to the following steps:

[0013] (1) The spodumene original ore is made into ore powder; the particle size of the ore powder is ≤0.08 mm; the ore powder A is continuously and quantitatively fed into the ore powder inlet of the dispersion dryer 1;

[0014] (2) Hot air at 450-500 °C is introduced through the air inlet at the bottom of the dispersion dryer 1. The hot air is mixed with the ore powder to disperse and dry the ore powder and preheat it to generate dried ore powder. The dried ore powder is discharged from the discharge port of the dispersion dryer 1 together with the hot air, enters the first separator 2, and is separated from the gas in the first separator 2. Under the condition of starting the induced draft fan, the dried ore powder enters the cyclone preheater 3 together with the hot air from the second separator 5;

[0015] (3) The dried ore powder exchanges heat with the hot air from the second separator 5 in the cyclone preheater 3 to form preheated ore powder, which is discharged from the discharge port of the cyclone preheater 3 and enters the suspension roasting furnace 4;

[0016] (4) Hot air is introduced through the air inlet at the bottom of the suspension roasting furnace 4, and fuel B is introduced through the fuel inlet of the suspension roasting furnace 4. The fuel burns in the furnace to heat the preheated ore powder, and the preheated ore powder is suspended under the action of the air flow. Part of the preheated ore powder undergoes crystal form transformation after being heated to generate pre-phase change ore powder, which is discharged from the upper discharge port of the suspension roasting furnace 4 together with the hot air and enters the second separator 5;

[0017] (5) The pre-phase change ore powder entering the second separator 5 continues to undergo crystal form transformation, then is separated from the gas, and then enters the phase change reactor 6;

[0018] (6) Fluidizing air C is introduced through the fluidizing air inlet at the bottom of the phase change reactor 6. The pre-phase change ore powder continues to undergo crystal form transformation in the phase change reactor 6 until the phase change is completed, generating fully phase-changed ore powder.

[0019] (7) The fully phase-changed ore powder enters the system suction pipe through the discharge port at the upper part of the phase change reactor 6 along with the fluidizing air. Under the condition of starting the induced draft fan, a negative pressure is formed inside the system, and air G is sucked in from the air inlet and enters the system suction pipe. The fully phase-changed ore powder is sent into the cyclone cooler 7 along with the air. The fully phase-changed ore powder is separated from the air in the cyclone cooler 7 and naturally cooled to generate pre-cooled ore powder, which enters the powder waste heat boiler 8.

[0020] (8) When hot water E is introduced into the heat exchange pipes inside the powder waste heat boiler 8, or when hot water E is introduced into the cooling jacket of the powder waste heat boiler 8, the hot water exchanges heat with the pre-cooled ore powder. The hot water generates steam F and is discharged from the steam outlet, and the pre-cooled ore powder generates low-temperature ore powder (calcined material D) and is discharged from the calcined material discharge port at the bottom of the powder waste heat boiler 8.

[0021] In the above step (1), the mass content of water in the ore powder ≤ 20%.

[0022] In the above step (2), the mass content of water in the dried ore powder ≤ 2%, and the temperature is 150 - 200 °C.

[0023] In the above step (3), the temperature of the hot gas from the second separator 5 is 1000 - 1100 °C.

[0024] In the above step (3), the temperature of the preheated ore powder is 450 - 500 °C.

[0025] In the above step (4), the fuel entering the suspension roasting furnace 4 is mixed with the hot gas at a temperature of 750 - 800 °C and then burns, controlling the temperature inside the suspension roasting furnace 4 to be 1000 - 1100 °C.

[0026] In the above step (4), the crystal form transformation is that spodumene transforms from the α crystal form to the β crystal form.

[0027] In the above step (4), the β-crystal spodumene accounts for 25 - 30% of the total mass of all spodumene.

[0028] In the above step (4), the residence time of the preheated ore powder in the suspension roasting furnace 4 is 2 - 5 s.

[0029] In the above step (5), the β-crystal spodumene in the pre-phase change ore powder accounts for 50 - 60% of the total mass of all spodumene.

[0030] In the above step (6), the β-crystal spodumene in the fully phase-changed ore powder accounts for more than 99% of the total mass of all spodumene.

[0031] In the above step (6), the fluidizing air is supplied by a Roots blower.

[0032] In the above step (6), the temperature inside the phase change reactor 6 is 950 - 1050 °C.

[0033] In the above step (6), the residence time of the pre-phase change ore powder in the phase change reactor 6 is 10 - 15 min.

[0034] In the above step (7), the temperature inside the cyclone cooler 7 is 750 - 800 °C.

[0035] In the above step (8), the temperature of the low-temperature ore powder is ≤ 80 °C.

[0036] In the above step (3), the hot gas that has undergone heat exchange in the cyclone preheater 3 is discharged from the gas outlet of the cyclone preheater 3 and introduced into the inlet of the bottom of the dispersion dryer 1.

[0037] In the above step (5), the heat-exchanged gas separated from the second separator 5 is discharged from the gas outlet of the second separator 5 and introduced into the feed inlet of the cyclone preheater 3.

[0038] In the above step (7), the heat-exchanged gas separated from the cyclone cooler 7 is discharged from the gas outlet of the cyclone cooler 7 and introduced into the inlet of the bottom of the suspension roasting furnace 4.

[0039] In the above step (2), the gas separated from the first separator 2 is discharged from the gas outlet of the first separator 2 and enters the waste gas purifier 9; the gas outlet of the waste gas purifier 9 is connected to the inlet of the induced draft fan 10; when the induced draft fan 10 is started, the gas entering the waste gas purifier 9 is separated into a waste gas part and a dust part; the waste gas part H is discharged with the induced draft fan 10; after the dust part is discharged from the bottom of the waste gas purifier 9, it is introduced into the cyclone preheater 3 and mixed with the ore powder.

[0040] The method of the present invention adopts the principle of fluidized suspension roasting of powder ore, can process spodumene ore powder with a particle size of 0.075 - 0.08 mm or less, has a short roasting time, precise temperature control, and will not cause the ore powder to agglomerate; a phase change reactor is set in the suspension roasting furnace device, so that α-type spodumene is fully converted into β-type spodumene, and the crystal form conversion rate can reach more than 99%; the roasting material is cooled by using a powder waste heat boiler to co-generate steam, and the waste heat is fully recovered.

[0041] A spodumene ore powder suspension roasting furnace device and a roasting method of the present invention have the following advantages:

[0042] 1. The process is simple, the processing capacity of a single set of equipment is large, the annual processing capacity of a single unit can reach 1 million tons, and the floor area is small, saving construction investment;

[0043] 2. Fast reaction speed and high efficiency. The time from the spodumene ore powder entering the device to the roasted material discharging is 15 - 20 minutes, which is 20% of the roasting time of the rotary kiln.

[0044] 3. Make full use of waste heat with low heat consumption. The heat consumption for treating each ton of spodumene ore powder is 60 - 70 kgce, which is 50% of the heat consumption of the rotary kiln.

[0045] 4. The roasting temperature can be controlled flexibly and stably, with a control temperature difference < 10°C. The quality of the roasted material is stable and the automation level is high.

[0046] 5. No waste residue is produced, and the waste gas is concentrated and easy to treat, which is environmentally friendly.

[0047] The present invention has the advantages of simple process, large processing capacity, small floor area, fast reaction speed, high efficiency, low energy consumption, small investment, no waste residue production, and the waste gas is concentrated and easy to treat. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Structural schematic diagram of the spodumene ore powder suspension roasting furnace device of the present invention;

[0049] In the figure: 1. Dispersion dryer, 2. First separator, 3. Cyclone preheater, 4. Suspension roasting furnace, 5. Second separator, 6. Phase change reactor, 7. Cyclone cooler, 8. Powder waste heat boiler, 9. Waste gas purifier, 10. Induced draft fan, A. Spodumene ore powder, B. Fuel, C. Fluidizing air, D. Roasted material, E. Hot water, F. Steam, G. Air, H. Waste gas. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] In the embodiment of the present invention, the phase change reactor is a fluidized bed, and the fluidizing air is sent into the fluidizing air inlet by the air supply equipment with air as the fluidizing air to fluidize the solid materials in the phase change reactor.

[0051] In the embodiment of the present invention, the fluidizing air C is introduced by a Roots blower.

[0052] In the embodiment of the present invention, the heat source of the suspension roasting furnace 4 comes from two parts. One part is the combustion heat provided by the fuel B sprayed into the fuel inlet of the suspension roasting furnace 4, and the other part is the hot gas at 750 - 800°C from the cyclone cooler, which is the waste heat released from cooling the fully phase-changed ore powder. The two heat sources maintain the roasting temperature in the roasting furnace at 1000 - 1100°C.

[0053] In the embodiment of the present invention, the dispersion dryer 1 is a Venturi dryer, a flash dryer or a drying and dispersing machine.

[0054] Example 1

[0055] The structure of the spodumene ore powder suspension roasting furnace device is as Figure 1As shown in the figure, it includes a dispersion dryer 1, a first separator 2, a cyclone preheater 3, a suspension roasting furnace 4, a second separator 5, a phase change reactor 6, a cyclone cooler 7, a powder waste heat boiler 8, an exhaust gas purifier 9 and a induced draft fan 10;

[0056] The dispersion dryer 1 is provided with an ore powder feed port; the air inlet of the dispersion dryer 1 is communicated with the air outlet of the cyclone preheater 3 through a pipeline; the discharge port of the dispersion dryer 1 is communicated with the feed port of the first separator 2; the discharge port of the first separator 2 is communicated with the feed port of the cyclone preheater 3; the discharge port of the cyclone preheater 3 is communicated with the feed port of the suspension roasting furnace 4; the discharge port of the suspension roasting furnace 4 is communicated with the feed port of the second separator 5; the discharge port of the second separator 5 is communicated with the feed port of the phase change reactor 6;

[0057] The discharge port of the phase change reactor 6 is communicated with the feed port of the cyclone cooler 7 through a system suction pipeline, and the system suction pipeline is provided with an air inlet for sucking air; the discharge port of the cyclone cooler 7 is communicated with the feed port of the powder waste heat boiler 8; the lower part of the suspension roasting furnace 4 is provided with a fuel inlet for introducing fuel; the bottom of the phase change reactor 6 is provided with a fluidizing air inlet for introducing fluidizing air; the air outlet of the first separator 2 is communicated with the air inlet of the exhaust gas purifier 9; the air outlet of the exhaust gas purifier 9 is communicated with the air inlet of the induced draft fan 10; the air outlet of the second separator 5 is communicated with the feed pipeline;

[0058] The bottom of the powder waste heat boiler 8 is provided with a roasted material discharge port;

[0059] The powder waste heat boiler 8 is provided with a water inlet and a steam outlet which are communicated with the heat exchange pipeline inside the powder waste heat boiler 8;

[0060] The air outlet of the cyclone preheater 3 is communicated with the air inlet of the dispersion dryer 1;

[0061] The air outlet of the cyclone cooler 7 is communicated with the air inlet at the bottom of the suspension roasting furnace 4;

[0062] The exhaust gas purifier 9 is a bag type dust collector;

[0063] The method is as follows:

[0064] (1) Making spodumene raw ore into ore powder; the particle size of the ore powder ≤ 0.08 mm; the mass content of water in the ore powder ≤ 20%; continuously and quantitatively feeding the ore powder A into the ore powder feed port of the dispersion dryer 1;

[0065] (2) Hot air at 450 °C is introduced through the air inlet at the bottom of the dispersion dryer 1. The hot air is mixed with the ore powder to disperse and dry the ore powder and preheat it to produce dried ore powder. The dried ore powder is discharged from the discharge port of the dispersion dryer 1 together with the hot air, enters the first separator 2, and is separated from the gas in the first separator 2. Under the condition of starting the induced draft fan, the dried ore powder enters the cyclone preheater 3 with the hot air from the second separator 5. The mass content of water in the dried ore powder is ≤2%, and the temperature is 150 °C.

[0066] (3) In the cyclone preheater 3, the dried ore powder exchanges heat with the hot air from the second separator 5 to form preheated ore powder, which is discharged from the discharge port of the cyclone preheater 3 and enters the suspension roasting furnace 4. The temperature of the hot air from the second separator 5 is 1000 °C. The temperature of the preheated ore powder is 450 °C. The hot air that has exchanged heat in the cyclone preheater 3 is discharged from the air outlet of the cyclone preheater 3 and introduced into the air inlet at the bottom of the dispersion dryer 1.

[0067] (4) Hot air is introduced through the air inlet at the bottom of the suspension roasting furnace 4, and fuel B is introduced through the fuel inlet of the suspension roasting furnace 4. The fuel burns in the furnace to heat the preheated ore powder, and the preheated ore powder is suspended by the airflow. Part of the preheated ore powder undergoes crystal form transformation after being heated to produce pre-phase change ore powder, which is discharged from the upper discharge port of the suspension roasting furnace 4 together with the hot air and enters the second separator 5. The fuel entering the suspension roasting furnace 4 burns after being mixed with the hot air at 750 °C, and the temperature in the suspension roasting furnace 4 is controlled at 1000 °C. The crystal form transformation is the transformation of spodumene from α crystal form to β crystal form. The β-crystal spodumene accounts for 25% of the total mass of spodumene. The residence time of the preheated ore powder in the suspension roasting furnace 4 is 2 s.

[0068] (5) The pre-phase change ore powder entering the second separator 5 continues to undergo crystal form transformation, then is separated from the gas, and then enters the phase change reactor 6. The β-crystal spodumene in the pre-phase change ore powder accounts for 50% of the total mass of spodumene. The heat-exchanged gas separated from the second separator 5 is discharged from the air outlet of the second separator 5 and introduced into the feed inlet of the cyclone preheater 3.

[0069] (6) Fluidizing air C is introduced through the fluidizing air inlet at the bottom of the phase change reactor 6. The pre-phase change ore powder continues to undergo crystal form transformation in the phase change reactor 6 until the phase change is completed to produce fully phase-changed ore powder. The β-crystal spodumene in the fully phase-changed ore powder accounts for more than 99% of the total mass of spodumene. The temperature in the phase change reactor 6 is 950 °C. The residence time of the pre-phase change ore powder in the phase change reactor 6 is 15 min.

[0070] (7) The fully phase - changed ore powder enters the system suction pipeline from the discharge port at the upper part of the phase - change reactor 6 along with the fluidizing air. Under the condition of starting the induced draft fan, a negative pressure is formed inside the system, and air G is sucked in from the air inlet and enters the system suction pipeline. The fully phase - changed ore powder is sent into the cyclone cooler 7 along with the air. The fully phase - changed ore powder is separated from the air in the cyclone cooler 7 and naturally cools down to generate pre - cooled ore powder, which enters the powder waste heat boiler 8. The temperature in the cyclone cooler 7 is 750 °C. The heat - exchanged gas separated from the cyclone cooler 7 is discharged from the air outlet of the cyclone cooler 7 and introduced into the air inlet at the bottom of the suspension roasting furnace 4.

[0071] (8) When hot water E is introduced into the heat - exchange pipeline inside the powder waste heat boiler 8, the hot water exchanges heat with the pre - cooled ore powder. The hot water generates steam F and is discharged from the steam outlet, and the pre - cooled ore powder generates low - temperature ore powder (roasting material D) and is discharged from the roasting material discharge port at the bottom of the powder waste heat boiler 8. The temperature of the low - temperature ore powder ≤ 80 °C.

[0072] The gas separated from the first separator 2 is discharged from the air outlet of the first separator 2 and enters the waste gas purifier 9. The air outlet of the waste gas purifier 9 is connected to the air inlet of the induced draft fan 10. When the induced draft fan 10 is started, the gas entering the waste gas purifier 9 is separated into waste gas part and dust part. The waste gas part H is discharged along with the induced draft fan 10. After the dust part is discharged from the bottom of the waste gas purifier 9, it is introduced into the cyclone pre - heater 3 and mixed with the ore powder.

[0073] Example 2

[0074] The structure of the spodumene ore powder suspension roasting furnace device is the same as that in Example 1, and the difference is that: the powder waste heat boiler 8 is provided with a water inlet and a steam outlet, which are connected to the cooling jacket of the powder waste heat boiler 8.

[0075] The method is the same as that in Example 1, and the differences are as follows:

[0076] (1) Hot gas at 500 °C is introduced into the air inlet at the bottom of the dispersion dryer 1. The temperature of the dried ore powder is 200 °C.

[0077] (2) The temperature of the hot gas from the second separator 5 is 1100 °C. The temperature of the pre - heated ore powder is 500 °C.

[0078] (3) The fuel entering the suspension roasting furnace 4 is mixed with the hot gas at 800 °C and then burns. The temperature inside the suspension roasting furnace 4 is controlled at 1100 °C. The β - spodumene accounts for 30% of the total mass of the spodumene. The residence time of the pre - heated ore powder in the suspension roasting furnace 4 is 5 s.

[0079] (4) The β - spodumene in the pre - phase - changed ore powder entering the phase - change reactor 6 accounts for 60% of the total mass of the spodumene.

[0080] (5) The temperature in the phase change reactor 6 is 1050°C; the residence time of the pre-phase change ore powder in the phase change reactor 6 is 10 min;

[0081] (6) The temperature inside the cyclone cooler 7 is 800°C; hot water E is introduced into the cooling jacket of the powder waste heat boiler 8.

[0082] Example 3

[0083] The structure of the spodumene ore powder suspension roasting furnace is the same as that of Example 1;

[0084] The method is the same as in Example 1, except that:

[0085] (1) Hot air at 480°C is introduced into the air inlet at the bottom of the dispersion dryer 1; the temperature of the mineral powder after drying is 180°C;

[0086] (2) The temperature of the hot gas from the second separator 5 is 1050°C; the temperature of the preheated ore powder is 480°C;

[0087] (3) The fuel entering the suspension roasting furnace 4 is mixed with the hot air at a temperature of 780°C and then burned, and the temperature in the suspension roasting furnace 4 is controlled to be 1050°C; the β-crystalline spodumene accounts for 28% of the total spodumene mass; the residence time of the preheated ore powder in the suspension roasting furnace 4 is 3s;

[0088] (4) The β-crystalline spodumene in the pre-phase change ore powder entering the phase change reactor 6 accounts for 55% of the total spodumene mass;

[0089] (5) The temperature in the phase change reactor 6 is 1000°C; the residence time of the pre-phase change ore powder in the phase change reactor 6 is 12 minutes;

[0090] (6) The temperature inside the cyclone cooler 7 is 780°C.

[0091] Comparative Example 1

[0092] A method for cyclic roasting and crystal transformation of natural spodumene with application number 2017109566687 is used to treat the same spodumene raw material;

[0093] This method adopts a cyclic roasting method, because according to the principle of suspension roasting, the material stays in the suspension roasting furnace for only a few seconds, and spodumene reaches the fastest crystal conversion rate at 1000~1100℃. It takes at least 10~15 minutes to complete all crystal conversions. Therefore, this method uses the method of returning the unqualified crystal materials to the suspension roasting furnace through the powder valve for re-roasting. Repeated cyclic roasting not only wastes energy and has high heat consumption, but is also more likely to cause the material to melt, scar and overburn in the burner area of ​​the roasting furnace;

[0094] The method and product use air cooling, which requires a large amount of air. After heat exchange, the air is discharged after entering the roasting system, carrying a large amount of waste heat and wasting resources.

[0095] Comparative Example 2

[0096] Adopt a spodumene powder suspension preheating and calcining crystal form transformation process with the application number 2021102855150 to process the same spodumene raw material;

[0097] The process of this method is complex. It adopts two-stage preheating, an independent combustion chamber separated from the suspension roasting furnace, and uses two induced draft fans to separate the preheating roasting and the product cooling system. The air volume is large and the energy consumption is high;

[0098] This method has a single roasting and no measures to increase the residence time of the material in the high-temperature zone, so it cannot ensure the crystal form transformation of the material.

[0099] Comparative Example 3

[0100] Adopt a method for suspension roasting of spodumene concentrate and a method for lithium extraction by suspension roasting of spodumene concentrate with the application number 2022100379845 to process the same spodumene raw material;

[0101] This method has no suspension roasting and is not feasible for continuous operation, so its practicality is limited.

Claims

1. A spodumene ore powder suspension roasting furnace device, characterized in that it includes a dispersion dryer (1), a first separator (2), a cyclone preheater (3), a suspension roasting furnace (4), a second separator (5), a phase change reactor (6), a cyclone cooler (7), a powder waste heat boiler (8), an exhaust gas purifier (9) and a draft fan (10); a mineral powder feed port is provided on the dispersion dryer (1); the air inlet of the dispersion dryer (1) is communicated with the air outlet of the cyclone preheater (3) through a pipeline; the discharge port of the dispersion dryer (1) is communicated with the feed port of the first separator (2); the discharge port of the first separator (2) is communicated with the feed port of the cyclone preheater (3) through a feed pipeline; the discharge port of the cyclone preheater (3) is communicated with the feed port of the suspension roasting furnace (4); the discharge port of the suspension roasting furnace (4) is communicated with the feed port of the second separator (5); the discharge port of the second separator (5) is communicated with the feed port of the phase change reactor (6); the discharge port of the phase change reactor (6) is communicated with the feed port of the cyclone cooler (7) through a system air suction pipeline, and an air inlet is provided on the system air suction pipeline for sucking air; the discharge port of the cyclone cooler (7) is communicated with the feed port of the powder waste heat boiler (8); a fuel inlet is provided at the lower part of the suspension roasting furnace (4) for introducing fuel; a fluidizing air inlet is provided at the bottom of the phase change reactor (6) for introducing fluidizing air; the air outlet of the first separator (2) is communicated with the air inlet of the exhaust gas purifier (9); the air outlet of the exhaust gas purifier (9) is communicated with the air inlet of the draft fan (10); the air outlet of the second separator (5) is communicated with the feed pipeline; a roasted material discharge port is provided at the bottom of the powder waste heat boiler (8); the air outlet of the cyclone preheater (3) is communicated with the air inlet of the dispersion dryer (1); the air outlet of the cyclone cooler (7) is communicated with the air inlet at the bottom of the suspension roasting furnace (4).

2. The spodumene ore powder suspension roasting furnace device according to claim 1, characterized in that the powder waste heat boiler is provided with a water inlet and a steam outlet which are communicated with the heat exchange pipeline inside the powder waste heat boiler or with the cooling jacket of the powder waste heat boiler.

3. A spodumene ore powder suspension roasting method, characterized in that the device according to claim 1 is adopted and the method is carried out according to the following steps: (1) The spodumene original ore is made into ore powder; the particle size of the ore powder is ≤ 0.08 mm; the ore powder is continuously and quantitatively fed into the ore powder feed port of the dispersion dryer; (2) Hot gas at 450 - 500 °C is introduced from the air inlet at the bottom of the dispersion dryer, the hot gas is mixed with the ore powder, the ore powder is dispersed and dried, and preheated to generate dried ore powder; the dried ore powder is discharged from the discharge port of the dispersion dryer together with the hot gas, enters the first separator, and is separated from the gas in the first separator and enters the cyclone preheater; (3) The dried ore powder exchanges heat with the hot gas from the second separator in the cyclone preheater to form preheated ore powder, which is discharged from the discharge port of the cyclone preheater 3 and enters the suspension roasting furnace; (4) Hot gas is introduced through the air inlet at the bottom of the suspension roasting furnace, and fuel is introduced through the fuel inlet of the suspension roasting furnace. The fuel burns in the furnace to heat the preheated ore powder, and the preheated ore powder is suspended under the action of the gas flow; part of the preheated ore powder undergoes crystal form transformation after being heated, generating pre-phase change ore powder, which is discharged from the discharge port at the upper part of the suspension roasting furnace along with the hot gas and enters the second separator; (5) The pre-phase change ore powder entering the second separator continues to undergo crystal form transformation, then is separated from the gas, and then enters the phase change reactor; (6) Fluidizing air is introduced through the fluidizing air inlet at the bottom of the phase change reactor, and the pre-phase change ore powder continues to undergo crystal form transformation in the phase change reactor until the phase change is completed, generating fully phase-changed ore powder; (7) The fully phase-changed ore powder enters the system suction pipeline from the discharge port at the upper part of the phase change reactor along with the fluidizing air; under the condition of starting the induced draft fan, a negative pressure is formed inside the system, and air is sucked in from the air inlet and enters the system suction pipeline. The fully phase-changed ore powder is sent into the cyclone cooler along with the air; the fully phase-changed ore powder is separated from the air in the cyclone cooler and naturally cools down to generate pre-cooled ore powder and enters the powder waste heat boiler; (8) When hot water is introduced into the heat exchange pipeline inside the powder waste heat boiler, or when hot water is introduced into the cooling jacket of the powder waste heat boiler, the hot water exchanges heat with the pre-cooled ore powder. The hot water generates steam and is discharged from the steam outlet, and the pre-cooled ore powder generates low-temperature ore powder and is discharged from the roasting material discharge port at the bottom of the powder waste heat boiler.

4. The method for suspension roasting spodumene ore powder according to claim 3, characterized in that in step (6), the β-crystalline spodumene in the fully phase-changed ore powder accounts for more than 99% of the total mass of spodumene.

5. The method for suspension roasting spodumene ore powder according to claim 3, characterized in that in step (5), the β-crystalline spodumene in the pre-phase change ore powder accounts for 50 - 60% of the total mass of spodumene.

6. The method for suspension roasting spodumene ore powder according to claim 3, characterized in that in step (6), the temperature in the phase change reactor 6 is 950 - 1050 °C.

7. The method for suspension roasting spodumene ore powder according to claim 3, characterized in that in step (6), the residence time of the pre-phase change ore powder in the phase change reactor 6 is 10 - 15 min.

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