CN113088682A - System and method for improving selectivity of artificial magnetite - Google Patents
System and method for improving selectivity of artificial magnetite Download PDFInfo
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- CN113088682A CN113088682A CN202110363691.1A CN202110363691A CN113088682A CN 113088682 A CN113088682 A CN 113088682A CN 202110363691 A CN202110363691 A CN 202110363691A CN 113088682 A CN113088682 A CN 113088682A
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Abstract
The invention discloses a system and a method for improving selectivity of artificial magnetite, wherein the system comprises a magnetization roasting furnace, a discharge hole of the magnetization roasting furnace is connected with a feed hole of a waste heat boiler, a discharge hole of the waste heat boiler is connected with a feed hole of a first material sealing device, a discharge hole of the first material sealing device is connected with a feed hole of a reoxidation reaction chamber, an air inlet at the bottom of the reoxidation reaction chamber is connected with a mixer through a mixed gas pipeline, a regulating valve, a flow meter and a pressure gauge are arranged on the mixed gas pipeline, the mixer is connected with a nitrogen pipeline and a compressed air pipeline, and the regulating valve and the flow meter are arranged on the nitrogen pipeline and the compressed air pipeline. The invention can prevent the artificial magnetite from being overoxidized to generate the hematite (alpha-Fe) with weak magnetism2O3) Obtaining maghemite (gamma-Fe) with strong magnetic characteristics2O3) The calcine of the method can greatly improve the selectivity of the artificial magnetite and has important guiding significance for the industrial production of mineral separation.
Description
Technical Field
The invention belongs to the field of metallurgy and mineral processing, and relates to a system and a method for improving selectivity of artificial magnetite.
Background
The complex refractory iron oxide ore in China has abundant resources, low iron grade of the resources, complex mineral composition, weak magnetism and fine disseminated granularity, and ideal separation indexes are difficult to obtain by adopting a conventional ore dressing process. After the ore is magnetized and roasted, the obtained artificial magnetite is subjected to magnetic separation, reverse flotation and other processes, so that better mineral separation indexes can be obtained.
In recent years, the flash magnetization roasting and suspension magnetization roasting technologies have been greatly researched and the fluidized magnetization roasting technology has been industrially applied. Compared with the traditional rotary kiln, shaft furnace and other magnetic roasting modes, the magnetic roasting device has higher application prospect. The cooling mode is also greatly improved, and the traditional water cooling mode has good cooling effect and high metal recovery rate, but magnetite has large residual magnetism and is difficult to separate.
Different iron ores are magnetized and roasted to obtain artificial magnetite, and the artificial magnetite is contacted with air in the fluidizing and cooling process and can generate reoxidation reaction to generate gamma-Fe2O3Or alpha-Fe2O3And release a large amount of reaction heat. gamma-Fe2O3Belongs to a strong magnetic mineral, can be effectively recovered by adopting low-intensity magnetic separation, and contains alpha-Fe2O3Belongs to weakly magnetic minerals, cannot be recovered by weak magnetic separation, and is easy to cause metal loss.
Disclosure of Invention
In view of the above technical problems, the present invention aims to create the condition for reoxidation of artificial magnetite and provides a system and a method for improving the selectivity of artificial magnetite.
A system for improving the selectivity of artificial magnetite comprises a magnetizing roasting furnace, wherein a discharge hole of the magnetizing roasting furnace is connected with a feed inlet of a waste heat boiler, a discharge hole of the waste heat boiler is connected with a feed inlet of a first material sealing device, a discharge hole of the first material sealing device is connected with a feed inlet of a reoxidation reaction chamber, an air distribution device and a metal sintering net are arranged at the bottom of the reoxidation reaction chamber, an air inlet at the bottom of the reoxidation reaction chamber is connected with a mixer through a mixed gas pipeline, a regulating valve, a flow meter and a pressure gauge are arranged on the mixed gas pipeline, the mixer is connected with a nitrogen pipeline and a compressed air pipeline, a regulating valve and a flow meter are arranged on the nitrogen pipeline and the compressed air pipeline, an air outlet pipe at the top of the reoxidation reaction chamber is connected with an air inlet of a dust remover, an oxygen analyzer is arranged on an air outlet pipe of the reoxida, and the discharge port of the second material sealing device is connected with a slurry making tank, and the slurry making tank is connected with a weak magnetic separation system.
The bottom parts of the first material sealing device and the first material sealing device are provided with metal sintering nets, nitrogen is introduced into the bottom parts of the first material sealing device and the first material sealing device, and the nitrogen is uniformly distributed through the metal sintering nets, so that materials in the device are in a fluidized state.
Be equipped with the baffle in first material sealing device and the first material sealing device, leave 180~220 mm's distance between baffle bottom and the metal sintering net. The baffle plate is used for blocking gas at the feed port end and the discharge port end of the material sealing device and preventing the gas from channeling with each other.
The method for improving the selectivity of the artificial magnetite by using the system comprises the following steps:
(1) carrying out magnetization roasting on powdery artificial magnetite with the granularity of less than 5mm to obtain high-temperature calcine, cooling the high-temperature calcine to 200-350 ℃ through heat exchange of a waste heat boiler, controlling the temperature of the calcine to be lower, and preventing the calcine from generating peroxidation reaction to generate weak magnetic hematite alpha-Fe when the temperature of the calcine is too high in a reoxidation reaction chamber2O3。
(2) And the cooled calcine enters a first material sealing device, and under the fluidization action of nitrogen, the calcine enters a reoxidation reaction chamber.
(3) And introducing mixed gas of nitrogen and air into the bottom of the re-oxidation reaction chamber, controlling the flow of the mixed gas to be 3000-4000 m for carrying out heavy planting/h, controlling the pressure to be 150-200 kpa, controlling the volume concentration of oxygen to be 0-20.9%, and accurately controlling the oxidation atmosphere through flow regulation to prevent the generation of 'overoxidation' into weakly magnetic mineral hematite (alpha-Fe 2O 3).
(4) The calcined product of the artificial magnetite is slowly discharged out of the reoxidation reaction chamber in a fluidized state under the action of the mixed gas, and in the process, the artificial magnetite Fe3O4The magnetite is contacted with oxygen in the mixed gas to generate micro-oxidation reaction, and part of magnetite crystal form is converted into maghemite or pseudohematite gamma-Fe2O3。
(5) And the micro-oxidation product slowly discharged from the reoxidation reaction chamber enters a slurry making tank for cooling and replenishing water for pulping through the fluidization effect of a second material sealing device, and the obtained roasting product with high selectivity is sent to subsequent weak magnetic separation.
The invention has the beneficial effects that:
1. the invention can accurately regulate and control the oxidizing atmosphere by fully contacting the air and nitrogen mixed gas with the calcine, avoid the occurrence of peroxidation, lead part of artificial magnetite to only have micro-oxidation reaction, and convert the crystal structure into the magnetite gamma-Fe2O3Thereby obtaining the calcine with higher selectivity than the traditional direct water cooling process, improving the selectivity of the artificial magnetite and being beneficial to subsequent separation.
2. The temperature of the calcine entering the reoxidation reaction chamber is controlled to be lower (200-350 ℃), and the condition that the calcine is too high and contacts with oxygen to generate peroxidation reaction to generate weak magnetic hematite alpha-Fe can be prevented2O3。
In conclusion, the invention prevents the artificial magnetite from being overoxidized to generate the weak magnetic hematite (alpha-Fe) by accurately regulating and controlling the oxidizing atmosphere and strictly controlling the temperature of the artificial magnetite contacting with oxygen2O3) Obtaining maghemite (gamma-Fe) with strong magnetic characteristics2O3) Calcine of (1)γ-Fe2O3Compared with artificial magnetite (Fe)3O4) The magnetic material has the characteristics of lower specific magnetization coefficient, small coercive force and easy demagnetization, can greatly improve the selectivity of the artificial magnetite and has important guiding significance for the mineral processing industrial production.
Drawings
FIG. 1 is a schematic diagram of a system for enhancing the selectivity of artificial magnetite according to the present invention;
FIG. 2 is a schematic view of the reoxidation chamber of the present invention;
fig. 3 is a schematic structural diagram of the sealing device of the present invention.
In the figure: 1-a magnetic roasting furnace, 2-a waste heat boiler, 3-a first material sealing device, 4-a reoxidation reaction chamber, 401-a reoxidation reaction chamber feeding hole, 402-an air distribution device, 403-a reoxidation reaction chamber metal sintering net, 404-an air inlet, 405-an air outlet pipe, 406-a reoxidation reaction chamber discharging hole, 5-a mixer, 6-a mixed gas pipeline, 7-a regulating valve, 8-a flow meter, 9-a pressure gauge, 10-a nitrogen pipeline, 11-a compressed air pipeline, 12-a dust remover, 13-an oxygen analyzer, 14-a second material sealing device, 15-a slurry making tank, 16-a weak magnetic separation system, 17-a partition plate and 18-a metal sintering net.
Detailed Description
The system and method for improving the selectivity of artificial magnetite according to the present invention will be further described with reference to the accompanying drawings.
As shown in fig. 1-3, a system for improving the selectivity of artificial magnetite comprises a magnetizing roasting furnace 1, a waste heat boiler 2, a first material sealing device 3, a reoxidation reaction chamber 4, a second material sealing device 14, a mixer 5, a dust remover 12, a nitrogen pipeline 10, a compressed air pipeline 11, a slurry making tank 15 and detection instruments 8, 9 and 13. The discharge hole of the magnetizing roasting furnace 1 is connected with the feed hole of the waste heat boiler 2, the discharge hole of the waste heat boiler 2 is connected with the feed hole of the first material sealing device 3, the discharge hole of the first material sealing device 3 is connected with the feed hole 401 of the reoxidation reaction chamber 4, and the bottom of the reoxidation reaction chamber 4 is provided with an air distribution device 402 and a metal sintering net 403. An air inlet 404 at the bottom of the reoxidation reaction chamber 1 is connected with a mixer 5 through a mixed gas pipeline 6, the mixed gas pipeline 6 is provided with a regulating valve 7, a flow meter 8 and a pressure gauge 9, the mixer 5 is connected with a nitrogen pipeline 10 and a compressed air pipeline 11, the nitrogen pipeline 10 and the compressed air pipeline 11 are provided with the regulating valve 7 and the flow meter 8, the nitrogen and the air accurately control the gas flow through the regulating valve 7 and are uniformly mixed in the mixer 5, and the mixed gas is conveyed into the reoxidation reaction chamber 4 through the mixed gas pipeline 6 after the pressure and the flow of the mixed gas are regulated through the control valve 7. An air outlet pipe 405 at the top of the reoxidation reaction chamber 1 is connected with an air inlet of the dust remover 12, and an oxygen analyzer 13 is arranged on the air outlet pipe 405.
The reoxidation reaction chamber 4 is a fluidized bed structure, the mixed gas is uniformly distributed through the air distribution device 401 and the metal sintering net 403 at the bottom after entering the reoxidation reaction chamber 4, and the calcine is in a fluidized state under the action of the mixed gas after entering the reoxidation reaction chamber 4. The mixed gas contacts with the calcine in the reoxidation reaction chamber 4 to generate micro-oxidation reaction, residual gas and part of fine ash enter the dust remover to remove dust through the air outlet pipe 405 at the top of the reoxidation reaction chamber 4, waste gas is discharged through a chimney, the removed dust enters the reoxidation reaction chamber 4, the oxygen analyzer 13 arranged on the air outlet pipe 405 can judge the degree of oxidation reaction in the reoxidation reaction chamber 4 by detecting the oxygen content in the waste gas.
The discharge hole 406 of the reoxidation reaction chamber 4 is connected with the feed hole of a second material sealing device 14, the discharge hole of the second material sealing device 14 is connected with a slurry making groove 15, and the slurry making groove is connected with a weak magnetic separation system 16
The bottom parts of the first material sealing device 3 and the first material sealing device 14 are provided with metal sintering nets 18, nitrogen is introduced into the bottom parts of the first material sealing device 3 and the first material sealing device 14, and the nitrogen is uniformly distributed through the metal sintering nets 18, so that the materials in the devices are in a fluidized state. The first material sealing device 3 and the second material sealing device 14 are internally provided with a partition plate 17, and a distance of 180-220 mm is reserved between the bottom end of the partition plate 17 and the metal sintering net 18. The baffle 17 is used for blocking gas at the feed port end and the discharge port end of the material sealing device and preventing gas from channeling.
A stirring device is arranged in the slurry making tank 15, the liquid level and the pulping concentration of the slurry making tank 15 are made through water supplementing and flow control, and the slurry is conveyed to subsequent weak magnetic separation through a slurry pump.
The method for improving the selectivity of the artificial magnetite by using the system comprises the following steps:
(1) carrying out magnetization roasting on powdery artificial magnetite with the granularity of less than 0.5mm in a magnetization roasting furnace 1 to obtain high-temperature calcine, cooling the high-temperature calcine to 200-350 ℃ through heat exchange of a waste heat boiler 2, controlling the temperature of the calcine to be lower, and preventing the calcine from generating peroxidation reaction to generate weak-magnetic hematite alpha-Fe when the temperature of a reoxidation reaction chamber is too high2O3。
(2) The cooled calcine enters a first material sealing device 3, and under the fluidization action of nitrogen, the calcine enters a reoxidation reaction chamber 4.
(3) Introducing mixed gas of nitrogen and air into the bottom of the re-oxidation reaction chamber, controlling the flow of the mixed gas to be 3000-4000 m/h, controlling the pressure to be 150-200 kpa, controlling the volume concentration of oxygen to be 0-20.9%, and accurately controlling the oxidation atmosphere by flow regulation to prevent the generation of 'overoxidation' to generate weakly magnetic mineral hematite (alpha-Fe)2O3）。
(4) The artificial magnetite calcine is slowly discharged from the reoxidation chamber 4 in a fluidized state under the action of the mixed gas, and in the process, the artificial magnetite Fe3O4The magnetite is contacted with oxygen in the mixed gas to generate micro-oxidation reaction, and part of magnetite crystal form is converted into maghemite or pseudohematite gamma-Fe2O3。
(5) And the micro-oxidation product slowly discharged from the reoxidation reaction chamber enters a slurry making tank 15 for cooling and replenishing water for pulping through the fluidization action of a second material sealing device 14, and the obtained roasting product with high selectivity is sent to subsequent weak magnetic separation.
Claims (6)
1. A system for improving the selectability of artificial magnetite, comprising: the device comprises a magnetizing roasting furnace, wherein a discharge port of the magnetizing roasting furnace is connected with a feed port of a waste heat boiler, the discharge port of the waste heat boiler is connected with a feed port of a first material sealing device, a discharge port of the first material sealing device is connected with a feed port of a reoxidation reaction chamber, an air distribution device and a metal sintering net are arranged at the bottom of the reoxidation reaction chamber, an air inlet at the bottom of the reoxidation reaction chamber is connected with a mixer through a mixed gas pipeline, a regulating valve, a flowmeter and a pressure gauge are arranged on the mixed gas pipeline, the mixer is connected with a nitrogen pipeline and a compressed air pipeline, the nitrogen pipeline and the compressed air pipeline are provided with a regulating valve and a flowmeter, an air outlet pipe at the top of the reoxidation reaction chamber is connected with an air inlet of a dust remover, an oxygen analyzer is arranged on an air outlet pipe of the reo, and the discharge port of the second material sealing device is connected with a slurry making tank, and the slurry making tank is connected with a weak magnetic separation system.
2. The system for improving the selectivity of artificial magnetite according to claim 1, wherein: and metal sintering nets are arranged at the bottoms of the first material sealing device and the second material sealing device.
3. The system for improving the selectivity of artificial magnetite according to claim 1, wherein: and partition plates are arranged in the first material sealing device and the second material sealing device, and a distance of 180-220 mm is reserved between the bottoms of the partition plates and the metal sintering net.
4. A method of increasing the selectivity of artificial magnetite using the system of claims 1-3, comprising the steps of:
(1) carrying out magnetization roasting on powdery artificial magnetite to obtain high-temperature roasted sand, and cooling the high-temperature roasted sand to 200-350 ℃ through heat exchange of a waste heat boiler;
(2) the cooled calcine enters a first material sealing device, and under the fluidization action of nitrogen, the calcine enters a reoxidation reaction chamber;
(3) introducing mixed gas of nitrogen and air into the bottom of the reoxidation reaction chamber, and controlling the volume concentration of oxygen to be 0-20.9%;
(4) the calcine is slowly discharged out of the reoxidation reaction chamber in a fluidized state under the action of the mixed gas, and in the process, the artificial magnetite Fe3O4Contact with oxygen in the mixed gas to generate micro-oxidation reaction, and part of magnetite crystal morphology is converted into strong magnetic hematite or false hematite gamma-Fe2O3；
(5) And finally, carrying out water-cooling pulping on the micro-oxidation product to obtain a roasting product with higher selectivity, and feeding the roasting product into subsequent weak magnetic separation.
5. The method of enhancing the selectivity of artificial magnetite as claimed in claim 1, wherein: in the step (1), the granularity of the powdery artificial magnetite is less than 5 mm.
6. The method of enhancing the selectivity of artificial magnetite as claimed in claim 1, wherein: in the step (3), the mixed gas flow is controlled to be 3000-4000 m for carrying out the dry-mass cultivation/h, and the pressure is controlled to be 150-200 kpa.
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| CN202110363691.1A CN113088682A (en) | 2021-04-02 | 2021-04-02 | System and method for improving selectivity of artificial magnetite |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114574712A (en) * | 2022-03-14 | 2022-06-03 | 沈阳铝镁设计研究院有限公司 | Roasting system and roasting process for reducing roasting temperature by adopting fluidized bed |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114574712A (en) * | 2022-03-14 | 2022-06-03 | 沈阳铝镁设计研究院有限公司 | Roasting system and roasting process for reducing roasting temperature by adopting fluidized bed |
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