High-temperature heat exchange controllable reduction roasting system and roasting method

Abstract

The invention relates to a high-temperature heat exchange controllable reduction roasting system and method, and belongs to the technical field of mineral processing, the system comprises a crushing treatment unit, a heat exchange unit, a heating reduction unit and a cooling and storage unit which are connected in sequence, and the crushing treatment unit is used for crushing raw materials; the heat exchange unit is used for carrying out heat exchange on crushed materials and carrying out gas-solid separation, the heating reduction unit is used for carrying out heating and reduction reaction, and the cooling and storage unit is used for cooling the materials after reduction reaction and carrying out final storage after treatment and magnetic separation; the heating reduction unit comprises a heating reactor and a reduction reactor which are connected with each other, and the heating reactor adopts high-temperature gas provided by a high-temperature recuperative furnace for heating. The high-temperature heat exchange furnace is adopted to heat materials in a heat exchange furnace mode, so that the materials are not in direct contact with flames, the rapid oxidation sintering phenomenon caused by contact of the materials and the flames is avoided, and the materials are uniformly heated.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a high-temperature heat exchange controllable reduction roasting system and a roasting method. Background Art

[0002] Iron ore is the main source of raw materials for steel production. Traditional mineral processing technology has problems such as long and complicated processes, difficult control, unstable indicators and low recovery rate. Some higher-grade materials cannot be used efficiently. Although qualified concentrates can be obtained, the concentrate yield and recovery rate are not high, resulting in varying degrees of resource waste.

[0003] Magnetic roasting is a process in which the ore is heated to a certain temperature and then subjected to physical and chemical reactions in a corresponding reaction atmosphere. It can transform weakly magnetic minerals into strongly magnetic minerals. Due to the magnetic difference between useful minerals and gangue minerals, magnetic separation technology is used to recover useful components in the minerals. According to the different types of magnetic roasting furnaces, the commonly used magnetic roasting methods can be divided into vertical furnace magnetic roasting, rotary kiln magnetic roasting, etc.

[0004] As a type of furnace mainly used to process lump ore, the vertical furnace is mainly divided into three parts from top to bottom: preheating zone, heating zone and reduction zone. During the entire roasting process, the ore stays in the vertical furnace for 6 to 10 hours. The vertical furnace roasting process has problems such as high energy consumption, low efficiency, and uneven product quality. Although the quality and sorting indicators of rotary kiln magnetized roasting are higher than those of the vertical furnace, for some powder ores with larger particle sizes, when their structure is denser, there will still be problems of uneven reduction inside and outside the ore; at the same time, the rotary kiln has poor gas-solid contact performance and high roasting energy consumption. During the magnetized roasting process, the rotary kiln is prone to "ringing" and affects its operation. High energy consumption and "ringing" problems are major obstacles to the promotion of rotary kilns in the field of magnetized roasting. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a high-temperature heat exchange controllable reduction roasting system and a roasting method, which adopts a high-temperature heat exchange furnace to provide hot air, thereby avoiding the burner flame directly contacting the material, which may easily lead to overoxidation and sintering of the material.

[0006] A high-temperature heat exchange controllable reduction roasting system, comprising a crushing processing unit, a heat exchange unit, a heating reduction unit and a cooling and storage unit connected in sequence, wherein the crushing processing unit is used to crush the raw material, the heat exchange unit is used to exchange heat for the crushed material and perform gas-solid separation, the heating reduction unit is used to generate heating and reduction reactions, and the cooling and storage unit is used to cool the material after the reduction reaction and finally store it after processing and magnetic separation;

[0007] The heating reduction unit comprises a heating reactor and a reduction reactor which are connected to each other. The heating reactor is heated by high-temperature gas provided by a high-temperature heat exchange furnace.

[0008] The crushing processing unit includes a raw material silo, a jaw crusher, a high-pressure roller mill, a material silo and a screw feeder which are connected in sequence. The discharge port of the raw material silo is connected to the feed ports of the jaw crusher and the high-pressure roller mill in sequence, and the discharge port of the high-pressure roller mill is connected to the feed port of the screw feeder for spiral feeding of the next unit.

[0009] The heat exchange unit includes a venturi dryer and a cyclone separator connected in sequence, the feed port of the venturi dryer is connected to the discharge port of the screw feeder of the crushing processing unit through a pipeline, and the discharge port of the venturi dryer is connected to the feed port of the cyclone separator through a pipeline.

[0010] The heat unit also includes a dust collecting device, the air outlet of the cyclone separator is connected to the air inlet of the dust collecting device through a pipe, the air outlet of the dust collecting device is connected to the air inlet of the negative pressure fan through a pipe, and one air outlet of the negative pressure fan is connected to the chimney through a pipe; the lower discharge port of the dust collecting device is connected to the cone discharge port of the cyclone separator through a pipe.

[0011] The discharge port of the cyclone separator is connected to the feed port of the heating reactor through a pipeline, and the discharge port of the heating reactor is connected to the feed port of the reduction reactor through a pipeline; the air inlet of the high-temperature heat exchange furnace is connected to the air outlet of the burner through a pipeline, and air and natural gas enter through the air inlet of the burner, and the burner ignites the natural gas and air and passes them into the high-temperature heat exchange furnace; the air inlet of the heating reactor is connected to the air outlet of the high-temperature heat exchange furnace through a pipeline, and a high-temperature electric-controlled valve is arranged between the air inlet of the heating reactor and the air outlet of the high-temperature heat exchange furnace.

[0012] The gas outlet of the heating reactor is connected to the gas inlet of the second purification device through a pipeline, and the gas outlet of the second purification device is connected to the gas inlet of the high-temperature heat exchange furnace;

[0013] The air inlet of the reduction reactor is connected to the reducing gas through a pipeline, the air outlet of the reduction reactor is connected to the air inlet of the first purification device through a pipeline, and the air outlet of the first purification device is connected to the air inlet of the burner through a pipeline;

[0014] Another air outlet of the negative pressure fan is communicated with the air inlet of the high-temperature heat exchange furnace.

[0015] The high-temperature heat exchange furnace includes two left and right chambers, each of which is provided with a high-temperature electric-controlled valve; the interiors of the two chambers are filled with high-temperature resistant medium, and an air inlet is provided at the bottom of the chamber; when working, the left and right chambers are heated and supplied alternately.

[0016] The cooling and storage unit comprises a cooler, a pulp pool, a grinding device and a weak magnetic separator which are sequentially connected through pipelines, the discharge port of the reduction reactor is connected to the feed port of the cooler through a pipeline, the discharge port of the cooler is connected to the feed port of the pulp pool through a pipeline, and the discharge port of the pulp pool is sequentially connected to the grinding device and the weak magnetic separator; the concentrate discharge port of the weak magnetic separator is connected to the feed port of the filter device through a pipeline, and the discharge port of the filter device is connected to the feed port of the first storage bin through a pipeline; the tailings discharge port of the weak magnetic separator is connected to the feed port of the thickener through a pipeline, and the discharge port of the thickener is connected to the second storage bin through a pipeline;

[0017] The air inlet of the cooler is communicated with the high-pressure air through a pipeline, and the air outlet of the cooler is communicated with the air inlet of the Venturi dryer of the heat exchange unit through a pipeline.

[0018] The venturi dryer, heating reactor, cooler, first purification device, second purification device, high temperature heat exchange furnace and dust collecting device in the high temperature heat exchange controllable reduction roasting system are all provided with thermocouple temperature measuring devices and pressure sensor devices electrically connected to the computer.

[0019] A high-temperature heat exchange controllable reduction roasting method is carried out using the above-mentioned high-temperature heat exchange controllable reduction roasting system, and specifically comprises the following steps:

[0020] Step 1: Iron ore of a certain particle size enters the raw material silo, the ore TFe grade is 30% to 50%, and the particle size is greater than 100mm. The material in the raw material silo enters the jaw crusher and the high-pressure roller mill in sequence through the discharge port through the belt. The material is crushed to -1mm. The crushed material enters the material silo through the belt, and the material enters the Venturi dryer of the heat exchange unit through the screw feeder;

[0021] Step 2: The material exchanges heat with the hot air entering from the air inlet at the bottom of the Venturi dryer. The heated material and the hot air after heat exchange are mixed and enter the cyclone separator through the discharge port at the top of the Venturi dryer for gas-solid separation. At this time, the material temperature rises to 100°C to 200°C, and the temperature of the hot air after heat exchange drops to 200°C to 300°C; the cooled hot air enters the dust collecting device through the discharge port at the top of the cyclone separator for further purification, and the purified air enters the chimney through the air outlet of the dust collecting device through the negative pressure fan, and is then discharged into the atmosphere; the dust generated by purification and the hot material enter the heating reactor of the heating reduction unit through the discharge port at the bottom of the cyclone separator;

[0022] Step 3: The hot gas in the high-temperature heat exchange furnace is metered by the high-temperature electric control valve and enters from the air inlet at the bottom of the heating reactor to exchange heat with the material. The temperature range of the hot gas is 700℃~800℃, so that the material is further heated to the specified temperature. The hot gas that completes the heat exchange is cooled to 300℃~400℃; after purification by the second purification device, it returns to the high-temperature heat exchange furnace from the bottom for further heating. The heat required for gas heating comes from the heat generated by the natural gas after combustion in the burner; the material that completes the heat exchange is heated to 450℃~550℃ and then enters the reduction reactor for reduction;

[0023] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor. The main components of the reducing gas are hydrogen or carbon monoxide or a mixed gas of hydrogen and carbon monoxide. The concentration range of the reducing gas is 20% to 45%, and the rest is nitrogen.

[0024] The reducing gas reacts chemically with the high-temperature hot material for 10 to 35 minutes. After the reaction, the material enters the cooler for cooling. After the reaction, the mixed gas is purified by the first purification device and then fed into the burner for combustion.

[0025] Step 5: The cold air required for material cooling enters from the bottom of the cooler, and the cold air is converted into hot gas heated to 350℃~450℃, and the hot gas enters the Venturi dryer for material heat exchange; the temperature of the cooled material is reduced to 100℃~200℃, and the cold material enters the slurry pool for slurry adjustment and then enters the grinding equipment for grinding, and the slurry concentration is controlled to be 40%~70%, and the grinding fineness of the grinding equipment is -200 mesh content 60%~95%, and the slurry ground to the required fineness enters the weak magnetic separator for weak magnetic separation, and the weak magnetic separation field strength is 0.1T~0.4T, and weak magnetic concentrate and weak magnetic tailings are obtained, and the TFe grade of the weak magnetic concentrate is greater than 65%;

[0026] Step 6: The weak magnetic concentrate product of the weak magnetic separator is filtered by the filtering device and discharged into the first storage bin for storage, and the weak magnetic tailings product is concentrated by the thickener and discharged into the second storage bin for storage.

[0027] The beneficial effects of the present invention are:

[0028] 1. The present invention adopts a high-temperature heat exchange furnace to heat the material by means of a heat exchange furnace, so that the material does not directly contact the flame, avoiding the rapid oxidation and sintering phenomenon caused by the contact between the material and the flame, and also achieving uniform heating of the material.

[0029] 2. The hot gas in the present invention is recycled, so that the heat loss of the system is reduced and the overall energy consumption is reduced.

[0030] 3. The high-temperature heat exchange furnace in the present invention can provide a continuous and stable heat source. When the iron ore is in powder form, it is heated. Since the material is fed into the roasting system with full particle size, the sintering of the micro-powder under high temperature conditions is avoided, so that the iron ore material can be quickly heated and react with the air. Since the powder is roasted, the reaction time is greatly shortened, which improves the roasting efficiency of the material and the quality of the roasted ore. After the roasted ore is processed by the "grinding-magnetic separation" process, under the condition of relatively low grinding fineness, the excellent indicators of iron grade greater than 65% and total iron recovery rate greater than 90% are finally obtained.

[0031] 4. This system is not only effective for iron ore, but also for some materials that require reduction roasting, such as the reduction and utilization of manganese oxide ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the connection and process flow of the high-temperature heat exchange controllable reduction roasting system provided by the present invention;

[0033] Figure 2 It is a working schematic diagram of the high temperature heat exchange furnace in the present invention;

[0034] in,

[0035] 1-raw material silo, 2-jaw crusher, 3-high pressure roller mill, 4-material silo, 5-screw feeder, 6-venturi dryer, 7-cyclone separator, 8-heating reactor, 9-reduction reactor, 10-cooler, 11-slurry pool, 12-grinding equipment, 13-weak magnetic separator, 14-thickener, 15-first storage silo, 16-filtering device, 17-second storage silo, 18-first purification device, 19-high temperature electric control valve, 20-high temperature heat exchange furnace, 21-burner, 22-second purification device, 23-dust collecting device, 24-negative pressure fan, 25-chimney. DETAILED DESCRIPTION

[0036] In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention are described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0037] Example 1

[0038] Combination Figure 1-2 As shown, this embodiment provides a high-temperature heat exchange controllable reduction roasting system, including a crushing processing unit, a heat exchange unit, a heating reduction unit and a cooling and storage unit connected in sequence.

[0039] The crushing processing unit is used to crush the raw materials, and includes a raw material silo 1, a jaw crusher 2, a high pressure roller mill 3, a material silo 4 and a screw feeder 5 which are connected in sequence. The discharge port of the raw material silo 1 is connected in sequence with the feed ports of the jaw crusher 2 and the high pressure roller mill 3, and the raw materials entering the raw material silo 1 are sequentially fed into the jaw crusher 2 and the high pressure roller mill 3 via a belt, and the raw materials are crushed in sequence; the discharge port of the high pressure roller mill 3 is connected with the feed port of the screw feeder 5, and is used for the screw feeding of the next unit.

[0040] The heat exchange unit is used to exchange heat for the crushed material and perform gas-solid separation, and includes a venturi dryer 6 and a cyclone separator 7 connected in sequence. The feed port of the venturi dryer 6 is connected to the discharge port of the screw feeder 5 of the crushing processing unit through a pipeline, and the discharge port of the venturi dryer 6 is connected to the feed port of the cyclone separator 7 through a pipeline.

[0041] The heat unit also includes a dust collecting device 23, the air outlet of the cyclone separator 7 is connected to the air inlet of the dust collecting device 23 through a pipeline, the air outlet of the dust collecting device 23 is connected to the air inlet of the negative pressure fan 24 through a pipeline, and one air outlet of the negative pressure fan 24 is connected to the chimney 25 through a pipeline; the lower discharge port of the dust collecting device 23 is connected to the conical discharge port of the cyclone separator 7 through a pipeline.

[0042] The heating reduction unit is used for heating and reduction reaction, and includes a heating reactor 8 and a reduction reactor 9 connected to each other. The discharge port of the cyclone separator 7 is connected to the feed port of the heating reactor 8 through a pipeline, and the discharge port of the heating reactor 8 is connected to the feed port of the reduction reactor 9 through a pipeline. The heating method of the heating reactor 8 is to use the high-temperature gas provided by the high-temperature heat exchange furnace 20 for heating. The air inlet of the high-temperature heat exchange furnace 20 is connected to the air outlet of the burner 21 through a pipeline, and air and natural gas enter from the air inlet of the burner 21. The burner 21 ignites the natural gas and air and then passes them into the high-temperature heat exchange furnace 20. The air inlet of the heating reactor 8 is connected to the air outlet of the high-temperature heat exchange furnace 20 through a pipeline, and a high-temperature electric control valve 19 is arranged between the air inlet of the heating reactor 8 and the air outlet of the high-temperature heat exchange furnace 20.

[0043] The gas outlet of the heating reactor 8 is connected to the gas inlet of the second purification device 22 through a pipeline, and the gas outlet of the second purification device 22 is connected to the gas inlet of the high-temperature heat exchange furnace 20. The gas inlet of the reduction reactor 9 is connected to the reduction gas through a pipeline, and the gas outlet of the reduction reactor 9 is connected to the gas inlet of the first purification device 18 through a pipeline, and the gas outlet of the first purification device 18 is connected to the gas inlet of the burner 21 through a pipeline. One gas outlet of the negative pressure fan 24 is connected to the gas inlet of the high-temperature heat exchange furnace 20.

[0044] The high-temperature heat exchange furnace 20 includes two left and right chambers, each of which is provided with a high-temperature electric control valve 19. The interior of the two chambers is filled with a high-temperature resistant medium. In this embodiment, the high-temperature resistant medium adopts a ceramic ball; an air inlet is provided at the bottom of the chamber. During operation, the left and right chambers are heated and supplied with heat alternately, that is, when the left chamber is heated, the right chamber has completed heating. At this time, the high-temperature electric control valve 19 corresponding to the left chamber is closed, and the gas channel and the high-temperature electric control valve 19 at the bottom of the right chamber are opened for gas supply; at this time, the temperature of the left chamber is low temperature, and the temperature of the right chamber is high temperature. When the right chamber is supplied with gas, a burner 21 is used to heat the high-temperature resistant medium in the left chamber, and the burner 21 is turned off after heating to a certain temperature; at this time, the right chamber has been supplied with gas for a period of time, and the temperature of the internal high-temperature resistant medium has decreased. At this time, the temperature of the right chamber is low temperature, and the temperature of the left chamber is high temperature. In order to better supply hot gas, close the high temperature electric control valve 19 corresponding to the right chamber, and open the gas channel at the bottom of the left chamber and the high temperature electric control valve 19 for gas supply; the right chamber uses a burner 21 to heat the high temperature resistant medium inside it. According to the above process, the left and right chambers are heated and supplied alternately to provide continuous and constant temperature hot gas for the heating reactor 8. In the actual operation process, the air required by the burner 21 and the high temperature heat exchange furnace 20 comes from not only external air and natural gas, but also part of it comes from the purified system exhaust gas, that is, the system exhaust gas purified by the dust collecting device 23, the first purification device 18, and the second purification device 22, so as to better utilize heat and reduce energy consumption.

[0045] The cooling and storage unit is used to cool the material after the reduction reaction and store it finally after processing and magnetic separation, and includes a cooler 10, a pulp pool 11, a grinding device 12 and a weak magnetic separator 13 which are connected in sequence through pipelines. The discharge port of the reduction reactor 9 is connected to the feed port of the cooler 10 through a pipeline, and the discharge port of the cooler 10 is connected to the feed port of the pulp pool 11 through a pipeline. The discharge port of the pulp pool 11 is connected to the grinding device 12 and the weak magnetic separator 13 in sequence. The concentrate discharge port of the weak magnetic separator 13 is connected to the feed port of the filter device 16 through a pipeline, and the discharge port of the filter device 16 is connected to the feed port of the first storage bin 15 through a pipeline; the tailings discharge port of the weak magnetic separator 13 is connected to the feed port of the thickener 14 through a pipeline, and the discharge port of the thickener 14 is connected to the second storage bin 17 through a pipeline to achieve final storage. The air inlet of the cooler 10 is communicated with the high-pressure air through a pipeline, and the air outlet of the cooler 10 is communicated with the air inlet of the Venturi dryer 6 of the heat exchange unit through a pipeline.

[0046] The Venturi dryer 6, the heating reactor 8, the cooler 10, the first purification device 18, the second purification device 22, the high-temperature heat exchange furnace 20 and the dust collecting device 23 in the high-temperature heat exchange controllable reduction roasting system are all provided with thermocouple temperature measuring devices and pressure sensor devices, which are electrically connected to the computer, and the temperature of each temperature measuring point and the pressure of each pressure measuring point are monitored and recorded in real time by the computer.

[0047] Example 2

[0048] This embodiment provides a high-temperature heat exchange controllable reduction roasting method, which is performed using the high-temperature heat exchange controllable reduction roasting system provided in Example 1. The raw material iron ore in this embodiment mainly contains hematite as the main iron mineral, the gangue mineral mainly contains quartz, and the raw material TFe grade is 30.97%. Specifically, the following steps are included:

[0049] Step 1: Hematite ore with a maximum particle size of 120 mm enters the raw material silo 1, and the TFe grade of the ore is 30.97%. The material in the raw material silo 1 enters the jaw crusher 2 and the high-pressure roller mill 3 in sequence through the discharge port through a belt. The material is crushed to -1 mm. The crushed material enters the material silo 4 through a belt, and the material enters the Venturi dryer 6 through a screw feeder 5.

[0050] Step 2: -1mm material is heat exchanged with the hot air entering from the bottom air inlet of the Venturi dryer 6. The heated material is mixed with the hot air after heat exchange and enters the cyclone separator 7 through the upper discharge port of the Venturi dryer 6 for gas-solid separation. At this time, the material is heated to 100°C, and the temperature of the hot air after heat exchange is reduced to 200°C; the cooled hot air enters the dust collecting device 23 through the discharge port at the top of the cyclone separator 7 for further purification. The purified air enters the chimney 25 through the air outlet of the dust collecting device 23 through the negative pressure fan 24 and is discharged into the atmosphere. The dust generated by purification and the hot material enter the heating reactor 8 through the bottom discharge port of the cyclone separator 7.

[0051] Step 3: The hot gas in the high-temperature heat exchange furnace 20 is controlled and metered by the high-temperature electric control valve 19 and enters from the bottom air inlet of the heating reactor 8 to exchange heat with the material. The temperature of the hot gas is 700°C, so that the material is further heated to the specified temperature. The hot gas that completes the heat exchange is cooled to 300°C, and is purified by the second purification device 22 and returned from the bottom to the high-temperature heat exchange furnace 20 for further heating. The heat required for gas heating comes from the heat generated by the combustion of natural gas in the burner 21; the material that has completed the heat exchange is heated to 450°C to form a high-temperature hot material and then enters the reduction reactor 9 for reduction.

[0052] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor 9. The main component of the reducing gas is hydrogen, and the concentration of the reducing gas is 20%. The rest is nitrogen, which serves as a protective gas. The reducing gas reacts chemically with the high-temperature hot material. The reaction time is 10 minutes. After the reaction is completed, the material enters the cooler 10 for cooling. After the reaction is completed, the mixed gas is purified by the first purification device 18 and then fed into the burner 21 for combustion.

[0053] Step 5: The cold air required for material cooling enters from the bottom of the cooler 10, and the cold air is converted into hot gas heated to 350°C, and the hot gas enters the venturi dryer 6 for material heat exchange; the temperature of the cooled material is reduced to 100°C, and the cold material enters the slurry pool 11 for slurry adjustment and then enters the grinding equipment 12 for grinding, and the slurry concentration is controlled to be 40%, and the grinding fineness of the grinding equipment 12 is -200 mesh and the content is 95%. The slurry ground to the required fineness enters the weak magnetic separator 13 for weak magnetic separation, and the weak magnetic separation field strength is 0.1T. The yield of weak magnetic concentrate is 42.77%, the TFe grade is 65.22%, the TFe recovery rate is 90.07%, and the TFe grade of the weak magnetic tailings is 6.02%.

[0054] Step 6: The weak magnetic concentrate product of the weak magnetic separator 13 is filtered by the filtering device 16 to the required moisture content and then discharged into the first storage bin 15 for storage. The weak magnetic tailings product is concentrated to the required concentration by the thickener 14 and then discharged into the second storage bin 17 for storage.

[0055] Example 3

[0056] This embodiment provides a high-temperature heat exchange controllable reduction roasting method, which is performed using the high-temperature heat exchange controllable reduction roasting system provided in Example 1. The main iron mineral of the iron ore in this embodiment is hematite, the gangue mineral is mainly quartz, and the raw material TFe grade is 34.51%. Specifically, the following steps are included:

[0057] Step 1: Hematite ore with a maximum particle size of 115 mm enters the raw material silo 1, and the TFe grade of the ore is 34.51%. The material in the raw material silo 1 enters the jaw crusher 2 and the high-pressure roller mill 3 in sequence through the discharge port through a belt. The material is crushed to -1 mm. The crushed material enters the material silo 4 through a belt, and the material enters the Venturi dryer 6 through a screw feeder 5.

[0058] Step 2: -1mm material is heat exchanged with the hot air entering from the bottom air inlet of the Venturi dryer 6. The heated material is mixed with the hot air after heat exchange and enters the cyclone separator 7 through the upper discharge port of the Venturi dryer 6 for gas-solid separation. At this time, the material is heated to 120°C, and the temperature of the hot air after heat exchange is reduced to 220°C; the cooled hot air enters the dust collecting device 23 through the top discharge port of the cyclone separator 7 for further purification, and the purified air enters the chimney 25 through the air outlet of the dust collecting device 23 through the negative pressure fan 24 and is discharged into the atmosphere. The dust generated by purification and the hot material enter the heating reactor 8 through the discharge port at the bottom of the cyclone separator 7.

[0059] Step 3: The hot gas in the high-temperature heat exchange furnace 20 is controlled and metered by the high-temperature electric control valve 19 and then enters from the bottom air inlet of the heating reactor 8 to exchange heat with the material. The temperature of the hot gas is 730°C, so that the material is further heated to the specified temperature. The hot gas that has completed the heat exchange is cooled to 330°C and purified by the second purification device 22. It returns to the high-temperature heat exchange furnace 20 from the bottom for further heating. The heat required for gas heating comes from the heat generated by the combustion of natural gas in the burner 21; the material that has completed the heat exchange is heated to 470°C to form a high-temperature hot material and then enters the reduction reactor 9 for reduction.

[0060] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor 9. The main component of the reducing gas is hydrogen, and the reducing gas concentration is 25%. The rest is nitrogen, which serves as a protective gas. The reducing gas reacts chemically with the high-temperature hot material. The reaction time is 15 minutes. After the reaction is completed, the material enters the cooler 10 for cooling. After the reaction is completed, the mixed gas is purified by the first purification device 18 and then fed into the burner 21 for combustion.

[0061] Step 5: The cold air required for material cooling enters from the bottom of the cooler 10, and the cold air is converted into hot gas heated to 370°C, and the hot gas enters the venturi dryer 6 for material heat exchange; the temperature of the cooled material is reduced to 120°C, and the cold material enters the slurry pool 11 for slurry adjustment and then enters the grinding equipment 12 for grinding, and the slurry concentration is controlled to be 50%, and the grinding fineness of the grinding equipment 12 is -200 mesh and the content is 90%. The slurry ground to the required fineness enters the weak magnetic separator 13 for weak magnetic separation, and the weak magnetic separation field strength is 0.1T. The yield of weak magnetic concentrate is 47.52%, the TFe grade is 65.74%, the TFe recovery rate is 90.52%, and the TFe grade of the weak magnetic tailings is 7.15%.

[0062] Step 6: The weak magnetic concentrate product of the weak magnetic separator 13 is filtered by the filtering device 16 to the required moisture content and then discharged into the first storage bin 15 for storage. The weak magnetic tailings product is concentrated to the required concentration by the thickener 14 and then discharged into the second storage bin 17 for storage.

[0063] Example 4

[0064] This embodiment provides a high-temperature heat exchange controllable reduction roasting method, which is performed using the high-temperature heat exchange controllable reduction roasting system provided in Example 1. The main iron mineral of the iron ore in this embodiment is hematite, the gangue mineral is mainly quartz, and the raw material TFe grade is 38.77%. Specifically, the following steps are included:

[0065] Step 1: Hematite ore with a maximum particle size of 140 mm enters the raw material silo 1, and the TFe grade of the ore is 38.77%. The material in the raw material silo 1 enters the jaw crusher 2 and the high-pressure roller mill 3 in sequence through the discharge port through a belt. The material is crushed to -1 mm. The crushed material enters the material silo 4 through a belt, and the material enters the Venturi dryer 6 through a screw feeder 5.

[0066] Step 2: -1mm material is heat exchanged with the hot air entering from the bottom air inlet of the Venturi dryer 6. The heated material is mixed with the hot air after heat exchange and enters the cyclone separator 7 through the upper discharge port of the Venturi dryer 6 for gas-solid separation. At this time, the material temperature rises to 130°C, and the temperature of the hot air after heat exchange is reduced to 230°C; the cooled hot air enters the dust collecting device 23 through the top discharge port of the cyclone separator 7 for further purification, and the purified air enters the chimney 25 through the air outlet of the dust collecting device 23 through the negative pressure fan 24 and is discharged into the atmosphere. The dust generated by purification and the hot material enter the heating reactor 8 through the bottom discharge port of the cyclone separator 7.

[0067] Step 3: The hot gas in the high-temperature heat exchange furnace 20 is controlled and metered by the high-temperature electric control valve 19 and then enters from the bottom air inlet of the heating reactor 8 to exchange heat with the material. The temperature of the hot gas is 750°C, so that the material is further heated to the specified temperature. The hot gas that has completed the heat exchange is cooled to 350°C and purified by the second purification device 22. Then, it returns to the high-temperature heat exchange furnace 20 from the bottom for further heating. The heat required for gas heating comes from the heat generated by the combustion of natural gas in the burner 21; the material that has completed the heat exchange is heated to 480°C to form a high-temperature hot material and then enters the reduction reactor 9 for reduction.

[0068] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor 9. The main component of the reducing gas is hydrogen, and the reducing gas concentration is 30%. The rest is nitrogen, which serves as a protective gas. The reducing gas reacts chemically with the high-temperature hot material. The reaction time is 20 minutes. After the reaction is completed, the material enters the cooler 10 for cooling. After the reaction is completed, the mixed gas is purified by the first purification device 18 and then fed into the burner 21 for combustion.

[0069] Step 5: The cold air required for material cooling enters from the bottom of the cooler 10, and the cold air is converted into hot gas heated to 380°C, and the hot gas enters the venturi dryer 6 for material heat exchange; the temperature of the cooled material is reduced to 140°C, and the cold material enters the slurry pool 11 for slurry adjustment and then enters the grinding equipment 12 for grinding, and the slurry concentration is controlled to be 55%, and the grinding fineness of the grinding equipment 12 is -200 mesh with a content of 80%. The slurry ground to the required fineness enters the weak magnetic separator 13 for weak magnetic separation, and the weak magnetic separation field strength is 0.15T. The yield of weak magnetic concentrate is 53.81%, the TFe grade is 65.98%, the TFe recovery rate is 91.57%, and the TFe grade of the weak magnetic tailings is 8.02%.

[0070] Step 6: The weak magnetic concentrate product of the weak magnetic separator 13 is filtered by the filtering device 16 to the required moisture content and then discharged into the first storage bin 15 for storage. The weak magnetic tailings product is concentrated to the required concentration by the thickener 14 and then discharged into the second storage bin 17 for storage.

[0071] Example 5

[0072] This embodiment provides a high-temperature heat exchange controllable reduction roasting method, which is performed using the high-temperature heat exchange controllable reduction roasting system provided in Example 1. The main iron mineral of the iron ore in this embodiment is hematite, the gangue mineral is mainly quartz, and the raw material TFe grade is 43.25%. Specifically, the following steps are included:

[0073] Step 1: Hematite ore with a maximum particle size of 130 mm enters the raw material silo 1, and the TFe grade of the ore is 43.25%. The material in the raw material silo 1 enters the jaw crusher 2 and the high-pressure roller mill 3 in sequence through the discharge port through a belt. The material is crushed to -1 mm. The crushed material enters the material silo 4 through a belt, and the material enters the Venturi dryer 6 through a screw feeder 5.

[0074] Step 2: -1mm material is heat exchanged with the hot air entering from the bottom air inlet of the Venturi dryer 6. The heated material is mixed with the hot air after heat exchange and enters the cyclone separator 7 through the upper discharge port of the Venturi dryer 6 for gas-solid separation. At this time, the material is heated to 150°C, and the temperature of the hot air after heat exchange is reduced to 250°C; the cooled hot air enters the dust collecting device 23 through the top discharge port of the cyclone separator 7 for further purification, and the purified air enters the chimney 25 through the air outlet of the dust collecting device 23 through the negative pressure fan 24 and is discharged into the atmosphere. The dust generated by purification and the hot material enter the heating reactor 8 through the bottom discharge port of the cyclone separator 7.

[0075] Step 3: The hot gas in the high-temperature heat exchange furnace 20 is controlled and metered by the high-temperature electric control valve 19 and then enters from the bottom air inlet of the heating reactor 8 to exchange heat with the material. The temperature of the hot gas is 770°C, so that the material is further heated to the specified temperature. The hot gas that has completed the heat exchange is cooled to 370°C and purified by the second purification device 22. Then, it returns to the high-temperature heat exchange furnace 20 from the bottom for further heating. The heat required for gas heating comes from the heat generated by the combustion of natural gas in the burner 21; the material that has completed the heat exchange is heated to 500°C to form a high-temperature hot material and then enters the reduction reactor 9 for reduction.

[0076] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor 9. The main component of the reducing gas is carbon monoxide, and the reducing gas concentration is 30%. The rest is nitrogen as a protective gas. The reducing gas reacts chemically with the high-temperature hot material. The reaction time is 20 minutes. After the reaction is completed, the material enters the cooler 10 for cooling. After the reaction is completed, the mixed gas is purified by the first purification device 18 and then fed into the burner 21 for combustion.

[0077] Step 5: The cold air required for material cooling enters from the bottom of the cooler 10, and the cold air is converted into hot gas heated to 380°C, and the hot gas enters the venturi dryer 6 for material heat exchange; the temperature of the cooled material is reduced to 150°C, and the cold material enters the slurry pool 11 for slurry adjustment and then enters the grinding equipment 12 for grinding, and the slurry concentration is controlled to be 55%, the grinding fineness of the grinding equipment 12 is -200 mesh and the content is 75%, and the slurry ground to the required fineness enters the weak magnetic separator 13 for weak magnetic separation, and the weak magnetic separation field strength is 0.2T, and the weak magnetic concentrate yield is 61.78%, the TFe grade is 66.05%, the TFe recovery rate is 94.35%, and the weak magnetic tailings TFe grade is 7.58%.

[0078] Step 6: The weak magnetic concentrate product of the weak magnetic separator 13 is filtered by the filtering device 16 to the required moisture content and then discharged into the first storage bin 15 for storage. The weak magnetic tailings product is concentrated to the required concentration by the thickener 14 and then discharged into the second storage bin 17 for storage.

[0079] Example 6

[0080] This embodiment provides a high-temperature heat exchange controllable reduction roasting method, which is performed using the high-temperature heat exchange controllable reduction roasting system provided in Example 1. The main iron mineral of the iron ore in this embodiment is hematite, the gangue mineral is mainly quartz, and the raw material TFe grade is 47.55%. Specifically, the following steps are included:

[0081] Step 1: Hematite ore with a maximum particle size of 150 mm enters the raw material silo 1, and the TFe grade of the ore is 47.55%. The material in the raw material silo 1 enters the jaw crusher 2 and the high-pressure roller mill 3 in sequence through the discharge port through a belt. The material is crushed to -1 mm. The crushed material enters the material silo 4 through a belt, and the material enters the Venturi dryer 6 through a screw feeder 5.

[0082] Step 2: -1mm material is heat exchanged with the hot air entering from the bottom air inlet of the Venturi dryer 6. The heated material is mixed with the hot air after heat exchange and enters the cyclone separator 7 through the upper discharge port of the Venturi dryer 6 for gas-solid separation. At this time, the material temperature rises to 170°C, and the temperature of the hot air after heat exchange is reduced to 280°C; the cooled hot air enters the dust collecting device 23 through the top discharge port of the cyclone separator 7 for further purification, and the purified air enters the chimney 25 through the air outlet of the dust collecting device 23 through the negative pressure fan 24 and is discharged into the atmosphere. The dust generated by purification and the hot material enter the heating reactor 8 through the bottom discharge port of the cyclone separator 7.

[0083] Step 3: The hot gas in the high-temperature heat exchange furnace 20 is controlled and metered by the high-temperature electric control valve 19 and enters from the bottom air inlet of the heating reactor 8 to exchange heat with the material. The temperature of the hot gas is 790°C, so that the material is further heated to the specified temperature. The hot gas that has completed the heat exchange is cooled to 390°C and purified by the second purification device 22. It returns to the high-temperature heat exchange furnace 20 from the bottom for further heating. The heat required for gas heating comes from the heat generated by the combustion of natural gas in the burner 21; the material that has completed the heat exchange is heated to 520°C to form a high-temperature hot material and then enters the reduction reactor 9 for reduction.

[0084] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor 9. The main components of the reducing gas are a mixed gas of carbon monoxide and hydrogen, with a reducing gas concentration of 35%, and the rest is nitrogen as a protective gas. The reducing gas reacts chemically with the high-temperature hot material for 25 minutes. After the reaction is completed, the material enters the cooler 10 for cooling. After the reaction is completed, the mixed gas is purified by the first purification device 18 and then fed into the burner 21 for combustion.

[0085] Step 5: The cold air required for material cooling enters from the bottom of the cooler 10, and the cold air is converted into hot gas heated to 400°C, and the hot gas enters the venturi dryer 6 for material heat exchange; the temperature of the cooled material is reduced to 170°C, and the cold material enters the slurry pool 11 for slurry adjustment and then enters the grinding equipment 12 for grinding, and the slurry concentration is controlled to be 60%, the grinding fineness of the grinding equipment 12 is -200 mesh and the content is 65%, and the slurry ground to the required fineness enters the weak magnetic separator 13 for weak magnetic separation, and the weak magnetic separation field strength is 0.3T, and the weak magnetic concentrate yield is 68.89%, the TFe grade is 66.31%, the TFe recovery rate is 96.07%, and the weak magnetic tailings TFe grade is 7.13%.

[0086] Step 6: The weak magnetic concentrate product of the weak magnetic separator 13 is filtered by the filtering device 16 to the required moisture content and then discharged into the first storage bin 15 for storage. The weak magnetic tailings product is concentrated to the required concentration by the thickener 14 and then discharged into the second storage bin 17 for storage.

[0087] Example 7

[0088] This embodiment provides a high-temperature heat exchange controllable reduction roasting method, which is performed using the high-temperature heat exchange controllable reduction roasting system provided in Example 1. The main iron mineral of the iron ore in this embodiment is hematite, the gangue mineral is mainly quartz, and the raw material TFe grade is 49.88%. Specifically, the following steps are included:

[0089] Step 1: Hematite ore with a maximum particle size of 150 mm enters the raw material silo 1, and the TFe grade of the ore is 49.88%. The material in the raw material silo 1 enters the jaw crusher 2 and the high-pressure roller mill 3 in sequence through the discharge port through a belt. The material is crushed to -1 mm. The crushed material enters the material silo 4 through a belt, and the material enters the Venturi dryer 6 through a screw feeder 5.

[0090] Step 2: -1mm material is heat exchanged with the hot air entering from the bottom air inlet of the Venturi dryer 6. The heated material is mixed with the hot air after heat exchange and enters the cyclone separator 7 through the upper discharge port of the Venturi dryer 6 for gas-solid separation. At this time, the material temperature rises to 200°C, and the temperature of the hot air after heat exchange is reduced to 300°C; the cooled hot air enters the dust collecting device 23 through the top discharge port of the cyclone separator 7 for further purification, and the purified air enters the chimney 25 through the air outlet of the dust collecting device 23 through the negative pressure fan 24 and is discharged into the atmosphere. The dust generated by purification and the hot material enter the heating reactor 8 through the bottom discharge port of the cyclone separator 7.

[0091] Step 3: The hot gas in the high-temperature heat exchange furnace 20 is controlled and metered by the high-temperature electric control valve 19 and enters from the bottom air inlet of the heating reactor 8 to exchange heat with the material. The temperature of the hot gas is 800°C, so that the material is further heated to the specified temperature. The hot gas that has completed the heat exchange is cooled to 400°C and purified by the second purification device 22. Then, it returns to the high-temperature heat exchange furnace 20 from the bottom for further heating. The heat required for gas heating comes from the heat generated by the combustion of natural gas in the burner 21; the material that has completed the heat exchange is heated to 520°C to form a high-temperature hot material and then enters the reduction reactor 9 for reduction.

[0092] Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor 9. The main components of the reducing gas are a mixed gas of carbon monoxide and hydrogen, with a reducing gas concentration of 45%, and the rest is nitrogen as a protective gas. The reducing gas reacts chemically with the high-temperature hot material, and the reaction time is 35 minutes. After the reaction is completed, the material enters the cooler 10 for cooling. After the reaction is completed, the mixed gas is purified by the first purification device 18 and then fed into the burner 21 for combustion.

[0093] Step 5: The cold air required for material cooling enters from the bottom of the cooler 10, and the cold air is converted into hot gas heated to 450°C, and the hot gas enters the venturi dryer 6 for material heat exchange; the temperature of the cooled material is reduced to 200°C, and the cold material enters the slurry pool 11 for slurry adjustment and then enters the grinding equipment 12 for grinding, the slurry concentration is controlled to be 70%, the grinding fineness of the grinding equipment 12 is -200 mesh and the content is 60%, and the slurry ground to the required fineness enters the weak magnetic separator 13 for weak magnetic separation, the weak magnetic separation field strength is 0.4T, and the weak magnetic concentrate yield is 72.26%, the TFe grade is 66.57%, the TFe recovery rate is 96.44%, and the weak magnetic tailings TFe grade is 7.50%.

[0094] Step 6: The weak magnetic concentrate product of the weak magnetic separator 13 is filtered by the filtering device 16 to the required moisture content and then discharged into the first storage bin 15 for storage. The weak magnetic tailings product is concentrated to the required concentration by the thickener 14 and then discharged into the second storage bin 17 for storage.

Claims

1. A high-temperature heat exchange controllable reduction roasting system, characterized in that: It includes a crushing unit, a heat exchange unit, a heating reduction unit and a cooling and storage unit connected in sequence, wherein the crushing unit is used to crush the raw materials, the heat exchange unit is used to exchange heat for the crushed materials and perform gas-solid separation, the heating reduction unit is used to heat and perform reduction reactions, and the cooling and storage unit is used to cool the materials after the reduction reaction and finally store them after processing and magnetic separation; The heating reduction unit comprises a heating reactor and a reduction reactor which are connected to each other. The heating reactor is heated by high-temperature gas provided by a high-temperature heat exchange furnace.

2. A high temperature heat exchange controllable reduction roasting system according to claim 1, characterized in that: The crushing processing unit includes a raw material silo, a jaw crusher, a high-pressure roller mill, a material silo and a screw feeder which are connected in sequence. The discharge port of the raw material silo is connected to the feed ports of the jaw crusher and the high-pressure roller mill in sequence, and the discharge port of the high-pressure roller mill is connected to the feed port of the screw feeder for spiral feeding of the next unit.

3. A high temperature heat exchange controllable reduction roasting system according to claim 1, characterized in that: The heat exchange unit includes a venturi dryer and a cyclone separator connected in sequence, the feed port of the venturi dryer is connected to the discharge port of the screw feeder of the crushing processing unit through a pipeline, and the discharge port of the venturi dryer is connected to the feed port of the cyclone separator through a pipeline.

4. A high temperature heat exchange controllable reduction roasting system according to claim 3, characterized in that: The heat unit also includes a dust collecting device, the air outlet of the cyclone separator is connected to the air inlet of the dust collecting device through a pipe, the air outlet of the dust collecting device is connected to the air inlet of the negative pressure fan through a pipe, and one air outlet of the negative pressure fan is connected to the chimney through a pipe; the lower discharge port of the dust collecting device is connected to the cone discharge port of the cyclone separator through a pipe.

5. A high temperature heat exchange controllable reduction roasting system according to claim 3, characterized in that: The discharge port of the cyclone separator is connected to the feed port of the heating reactor through a pipeline, and the discharge port of the heating reactor is connected to the feed port of the reduction reactor through a pipeline; the air inlet of the high-temperature heat exchange furnace is connected to the air outlet of the burner through a pipeline, and air and natural gas enter through the air inlet of the burner, and the burner ignites the natural gas and air and passes them into the high-temperature heat exchange furnace; the air inlet of the heating reactor is connected to the air outlet of the high-temperature heat exchange furnace through a pipeline, and a high-temperature electric-controlled valve is arranged between the air inlet of the heating reactor and the air outlet of the high-temperature heat exchange furnace.

6. A high temperature heat exchange controllable reduction roasting system according to claim 5, characterized in that: The gas outlet of the heating reactor is connected to the gas inlet of the second purification device through a pipeline, and the gas outlet of the second purification device is connected to the gas inlet of the high-temperature heat exchange furnace; The air inlet of the reduction reactor is connected to the reducing gas through a pipeline, the air outlet of the reduction reactor is connected to the air inlet of the first purification device through a pipeline, and the air outlet of the first purification device is connected to the air inlet of the burner through a pipeline; Another air outlet of the negative pressure fan is communicated with the air inlet of the high-temperature heat exchange furnace.

7. The high-temperature heat exchange controllable reduction roasting system according to claim 5, characterized in that: The high-temperature heat exchange furnace includes two left and right chambers, each of which is provided with a high-temperature electric-controlled valve; the interiors of the two chambers are filled with high-temperature resistant medium, and an air inlet is provided at the bottom of the chamber; when working, the left and right chambers are heated and supplied alternately.

8. The high-temperature heat exchange controllable reduction roasting system according to claim 1, characterized in that: The cooling and storage unit comprises a cooler, a pulp pool, a grinding device and a weak magnetic separator which are sequentially connected through pipelines, the discharge port of the reduction reactor is connected to the feed port of the cooler through a pipeline, the discharge port of the cooler is connected to the feed port of the pulp pool through a pipeline, and the discharge port of the pulp pool is sequentially connected to the grinding device and the weak magnetic separator; the concentrate discharge port of the weak magnetic separator is connected to the feed port of the filter device through a pipeline, and the discharge port of the filter device is connected to the feed port of the first storage bin through a pipeline; the tailings discharge port of the weak magnetic separator is connected to the feed port of the thickener through a pipeline, and the discharge port of the thickener is connected to the second storage bin through a pipeline; The air inlet of the cooler is communicated with the high-pressure air through a pipeline, and the air outlet of the cooler is communicated with the air inlet of the Venturi dryer of the heat exchange unit through a pipeline.

9. A high temperature heat exchange controllable reduction roasting system according to any one of claims 1 to 8, characterized in that: The venturi dryer, heating reactor, cooler, first purification device, second purification device, high temperature heat exchange furnace and dust collecting device in the high temperature heat exchange controllable reduction roasting system are all provided with thermocouple temperature measuring devices and pressure sensor devices electrically connected to the computer.

10. A high-temperature heat exchange controllable reduction roasting method, using a high-temperature heat exchange controllable reduction roasting system according to any one of claims 1 to 9, characterized in that: The specific steps include: Step 1: Iron ore of a certain particle size enters the raw material silo, the ore TFe grade is 30% to 50%, and the particle size is greater than 100mm. The material in the raw material silo enters the jaw crusher and the high-pressure roller mill in sequence through the discharge port through the belt. The material is crushed to -1mm. The crushed material enters the material silo through the belt, and the material enters the Venturi dryer of the heat exchange unit through the screw feeder; Step 2: The material exchanges heat with the hot air entering from the air inlet at the bottom of the Venturi dryer. The heated material and the hot air after heat exchange are mixed and enter the cyclone separator through the discharge port at the top of the Venturi dryer for gas-solid separation. At this time, the material temperature rises to 100°C to 200°C, and the temperature of the hot air after heat exchange drops to 200°C to 300°C; the cooled hot air enters the dust collecting device through the discharge port at the top of the cyclone separator for further purification, and the purified air enters the chimney through the air outlet of the dust collecting device through the negative pressure fan, and is then discharged into the atmosphere; the dust generated by purification and the hot material enter the heating reactor of the heating reduction unit through the discharge port at the bottom of the cyclone separator; Step 3: The hot gas in the high-temperature heat exchange furnace is metered by the high-temperature electric control valve and enters from the air inlet at the bottom of the heating reactor to exchange heat with the material. The temperature range of the hot gas is 700℃~800℃, so that the material is further heated to the specified temperature. The hot gas that completes the heat exchange is cooled to 300℃~400℃; after purification by the second purification device, it returns to the high-temperature heat exchange furnace from the bottom for further heating. The heat required for gas heating comes from the heat generated by the natural gas after combustion in the burner; the material that completes the heat exchange is heated to 450℃~550℃ and then enters the reduction reactor for reduction; Step 4: The reducing gas required for reduction enters from the bottom of the reduction reactor. The main components of the reducing gas are hydrogen or carbon monoxide or a mixed gas of hydrogen and carbon monoxide. The concentration range of the reducing gas is 20% to 45%, and the rest is nitrogen. The reducing gas reacts chemically with the high-temperature hot material for 10 to 35 minutes. After the reaction, the material enters the cooler for cooling. After the reaction, the mixed gas is purified by the first purification device and then fed into the burner for combustion. Step 5: The cold air required for material cooling enters from the bottom of the cooler, and the cold air is converted into hot gas heated to 350℃~450℃, and the hot gas enters the Venturi dryer for material heat exchange; the temperature of the cooled material is reduced to 100℃~200℃, and the cold material enters the slurry pool for slurry adjustment and then enters the grinding equipment for grinding, and the slurry concentration is controlled to be 40%~70%, and the grinding fineness of the grinding equipment is -200 mesh content 60%~95%, and the slurry ground to the required fineness enters the weak magnetic separator for weak magnetic separation, and the weak magnetic separation field strength is 0.1T~0.4T, and weak magnetic concentrate and weak magnetic tailings are obtained, and the TFe grade of the weak magnetic concentrate is greater than 65%; Step 6: The weak magnetic concentrate product of the weak magnetic separator is filtered by the filtering device and discharged into the first storage bin for storage, and the weak magnetic tailings product is concentrated by the thickener and discharged into the second storage bin for storage.

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