A pyrite suspension flash smelting apparatus and method

Abstract

The application discloses a pyrite suspension flash smelting device and method. The device is a three-furnace structure smelting device, the middle part of which is a suspension oxidation smelting furnace, the left side of which is an SO2 flue and an SO2 flue gas gravity settling chamber, and the right side of which is a reduction smelting bath and a reduction flue gas gravity settling chamber above the reduction smelting bath; the device combines the suspension oxidation smelting and the bath reduction smelting, is connected by a channel between the two smelting baths, and has the characteristics of high energy utilization efficiency of a reactor and non-interference of oxidation and reduction of two reactors. The pyrite suspension flash oxidation smelting is carried out by using pure oxygen and preheated pyrite powder, the smelting efficiency of the pyrite powder is improved, no special fuel is needed, carbon dioxide emission is reduced, one-step pyrite iron smelting is realized, the utilization rate of iron resources is improved, and environmental pollution is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a pyrite suspension flash smelting device and method, belonging to the field of metallurgy. BACKGROUND

[0002] Reducing coal consumption and carbon dioxide emissions is an important task and development direction of the steel smelting industry. Pyrite is the second largest iron resource on earth after iron oxide ore, and the proven reserves of pyrite in China account for 10% of the world's reserves. In the past, pyrite was mainly used to produce sulfuric acid. Improving the utilization rate of pyrite iron resources is an important means to meet the global shortage of iron resources. Taking advantage of the self-ignitability of pyrite, adopting an oxidation-reduction combined smelting method to smelt iron can not only reduce carbon dioxide emissions in steel smelting, but also improve the security of global iron resources, which is a technical direction that people have been thinking about recently. Chinese patent CN102586618A (name: smelting process of pyrite, application number: 201210095263.6) discloses a pyrite bath oxidation smelting ironmaking technology. This technology has low efficiency of bath oxidation smelting. Therefore, it is necessary to provide a more efficient pyrite smelting device and method for the development of the industry. SUMMARY

[0003] The present application aims to provide a pyrite suspension flash smelting device and method, which is a new device and method for smelting pyrite powder in suspension, and has significant creativity, novelty and practicality.

[0004] The present application provides a pyrite suspension flash smelting device, which is a three-furnace structure smelting device. The middle is a suspension oxidation smelting furnace. The left side of the suspension oxidation smelting furnace is a SO2 flue gas gravity settling chamber. The right side is a reduction smelting bath and a reduction flue gas gravity settling chamber above the reduction smelting bath.

[0005] Further, the suspension oxidation smelting furnace is a vertical cylindrical material top spraying smelting furnace composed of a membrane water cooling wall. The top is provided with a pyrite powder and oxygen nozzle. The smelting furnace is an oxidation melting suspension smelting zone. The lower part of the smelting furnace is a suspension oxidation smelting furnace bath. The upper left part of the suspension oxidation smelting furnace bath is an SO2 flue. The SO2 flue gas gravity settling chamber is connected to the SO2 flue. The lower right part of the suspension oxidation smelting furnace bath is communicated with the reduction smelting bath. The channel between the oxidation smelting bath and the reduction smelting bath has a cross-sectional area matching the suspension oxidation smelting output. From left to right, there is a 0-5 degree slope. High-iron oxidation molten material can only flow from the oxidation bath to the reduction bath. The reduction smelting bath is rectangular. The right end of the reduction smelting bath is provided with an upper slag outlet and a lower slag outlet. An iron outlet is arranged at the lower right end of the reduction smelting bath. The iron outlet is connected to a steel smelting furnace. A reduction flue gas outlet is arranged at the top of the reduction flue gas gravity settling chamber.

[0006] The upper part of the suspension oxidation smelting furnace and the upper part of the reduction gas gravity settling chamber are respectively provided with a furnace body preheating device; the furnace body preheating device needs to heat the smelting device to 1400-1700 degrees to start feeding each time the production starts.

[0007] The top of the suspension oxidation smelting furnace is provided with a vortex stirring multi-channel combustion nozzle; the lower part of the left SO2 flue gas gravity settling chamber is provided with a dust outlet, and the top is provided with an SO2 flue gas outlet, which is connected with a waste heat recovery device, and the waste heat recovery device is connected with a sulfuric acid or sulfur device.

[0008] Further, a plurality of reduction agent inlets are staggered on both sides of the rectangular reduction smelting bath.

[0009] Further, the reduction flue gas outlet at the upper part of the reduction flue gas gravity settling chamber is connected with a pyrite powder preheating device, and the pyrite powder preheating device is connected with the pyrite powder injection port of the suspension oxidation smelting furnace.

[0010] The present application provides a pyrite suspension flash smelting method, and the self-ignition oxidation smelting of pyrite and the bath reduction smelting are a continuous process, and the method specifically comprises the following steps:

[0011] (1) The preheated pyrite powder and pure oxygen are sprayed into the smelting furnace from the burner at the top of the suspension oxidation smelting furnace, and the oxidation smelting is carried out by utilizing the self-ignition of sulfur, and the combustion temperature is controlled to be 1400-1700 DEG C;

[0012] (2) The high-temperature SO2 flue gas generated by combustion is sucked into the SO2 flue gas gravity settling chamber through a micro-negative pressure from the SO2 flue gas chimney at the left upper part of the oxidation smelting bath, the dust settled down is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber, and the SO2 flue gas preliminarily purified is discharged from the flue gas outlet at the top of the SO2 flue gas gravity settling chamber into the SO2 flue gas waste heat utilization device; the SO2 flue gas after waste heat utilization is used to produce sulfur or sulfuric acid in the sulfuric acid or sulfur device;

[0013] (3) In the suspension oxidation smelting furnace, the molten high-iron oxide self-oxidation smelting area falls into the lower part of the suspension oxidation smelting furnace bath in suspension;

[0014] (4) The molten high-iron oxide falling into the lower part of the suspension oxidation smelting furnace bath enters the left reduction smelting bath through the right lower part of the suspension oxidation smelting bath, and is continuously reduced and smelted with the reducing agent sprayed into the reducing agent inlet on the reduction smelting bath, and the reduction flue gas is discharged from the reduction flue gas chimney at the upper part of the reduction flue gas gravity settling chamber;

[0015] (5) The low specific gravity slag produced by reduction smelting is discharged from the upper slag outlet of the reduction smelting bath, the high specific gravity slag is discharged from the lower slag outlet of the reduction smelting bath, and the molten iron is discharged from the molten iron outlet into the steelmaking furnace for steelmaking.

[0016] In the method, the SO2 flue gas entering the left SO2 flue is operated under micro-negative pressure, and the negative pressure environment is provided by the induced draft fan of the waste heat utilization device; the micro-negative pressure zero point is arranged at the left side of the SO2 flue of the upper part of the molten pool of the oxygen smelting furnace.

[0017] In the method, the pyrite powder has a particle size of 200-300 meshes; and lime and fluorite are added to the pyrite powder as needed to form slag.

[0018] In the method, the pyrite suspension flash smelting method further comprises: the cold pyrite powder is sprayed into the lower opening of the preheating device outside the reduction flue gas outlet, and exchanges heat with the high-heat reduction flue gas entering from the lower part to preheat the pyrite powder; and the preheated pyrite powder is collected and then enters the smelting furnace from the preheated pyrite powder + oxygen gas spraying opening.

[0019] In the method, the reducing agent for reduction smelting includes but is not limited to one of hydrogen, carbon monoxide, natural gas, LPG or coal powder; and the coal powder is carried and sprayed by using oxygen-rich hot air.

[0020] In the method, the amount of the pyrite powder and oxygen in the raw material is calculated based on the components of iron disulfide and oxygen, and the molar ratio of the two is 1:2-1:3.

[0021] The method specifically comprises the following steps:

[0022] (1) Start the furnace body preheating program of the suspension flash smelting device, spray natural gas or fuel oil from the spraying opening at the upper part of the furnace body to ignite, and stabilize the temperature of the suspension smelting furnace and the reduction smelting molten pool furnace to 1400-1700℃;

[0023] (2) In the initial stage of the process, open the slag outlet and the molten iron outlet on the molten pool, and when the temperature of the molten pool is stabilized at 1400-1700℃, close the upper and lower slag outlets and the molten iron outlet;

[0024] (3) When the temperature of the smelting furnace is stabilized to 1400-1700℃, start the induced draft fan of the SO2 flue gas waste heat utilization device to provide negative pressure for the SO2 flue gas, and after the negative pressure is stabilized, spray the preheated pyrite powder and oxygen from the preheated pyrite powder and oxygen burner arranged at the top of the smelting furnace according to the amount ratio to preheat the pyrite powder and oxygen, and oxidize and smelt the pyrite powder;

[0025] (4) After the pyrite powder starts to oxidize and smelt, when the high-iron molten material in the oxidation smelting molten pool and the reduction smelting molten pool exceeds the reduction agent spraying opening on the reduction smelting molten pool, spray the reduction agent from the reduction agent spraying opening to perform reduction smelting; the process of reduction blowing is also the process of slag-iron separation;

[0026] (5) The molten iron, which has completed the reduction reaction, is discharged from the molten iron outlet into a steelmaking furnace for steelmaking, and the high specific gravity slag is discharged from the slag outlet below the molten pool, and the low specific gravity slag is discharged from the slag outlet above the molten pool;

[0027] (6) The high-temperature reduction smelting flue gas is discharged from the flue gas outlet at the upper part of the reduction flue gas gravity settling chamber, and is used for preheating pyrite powder in parallel flow heat exchange with the cold pyrite powder entering from the lower inlet of the pyrite powder preheating device, the preheated pyrite powder has a temperature of no more than 400 ℃, and the preheated pyrite powder is sprayed into the smelting furnace through the preheated pyrite powder + oxygen gas nozzle.

[0028] The beneficial effects of the present application are as follows:

[0029] (1) The pure oxygen and the preheated pyrite powder are used for suspension flash smelting, so that the smelting efficiency of the pyrite powder is improved, and only a small amount of carbon dioxide is discharged without using special fuel.

[0030] (2) The suspension oxidation smelting and the molten pool reduction smelting are carried out in two reactors, the high-iron molten material realizes continuous reduction and oxidation reactions through the channels on the two molten pools, the whole device has the characteristics of high energy utilization efficiency of one reactor and the characteristics of non-interference between oxidation and reduction of two reactors.

[0031] (3) The pyrite one-step ironmaking is realized, the utilization rate of iron resources is improved, and the carbon emission and environmental pollution are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of the pyrite suspension flash smelting device.

[0033] In the figure: 1, suspension oxidation smelting furnace; 2, pyrite powder and oxygen gas nozzle; 3, SO2 flue; 4, SO2 flue gas gravity settling chamber; 5, dust outlet; 6, SO2 flue gas outlet; 7, waste heat utilization device; 8, sulfuric acid and sulfur device; 9, oxidation smelting molten pool; 10, reduction smelting molten pool; 11, molten pool channel; 12, reduction agent inlet; 13, reduction flue gas gravity settling chamber; 14, reduction flue gas flue; 15, pyrite powder preheating device; 16, low specific gravity slag outlet; 17, high specific gravity slag outlet; 18, molten iron outlet; 19, steelmaking furnace; 20, furnace body preheating device. DETAILED DESCRIPTION

[0034] The present application will be further described below by examples, but is not limited to the following examples.

[0035] As shown in the figure, a pyrite powder suspension flash smelting device comprises a suspension oxidation smelting furnace 1 and a smelting furnace material inlet 2 in the middle of the device; a SO2 flue 3 and a SO2 flue gas gravity settling chamber 4 and a system after the same on the left side of the device; an oxidation smelting furnace bath 9 at the lower part of the suspension oxidation smelting furnace 1 of the device, a reduction smelting bath 10 on the left side of the device, a bath channel 11 connecting the oxidation smelting furnace bath 9 and the reduction smelting bath 10; further comprising a reducing agent inlet 12 distributed on both sides of the reduction smelting bath; a reduction gas gravity settling chamber 13 at the upper part of the reduction smelting bath and a reduction gas gravity settling chamber after system reduction flue gas flue 14 and a pyrite powder preheating device 15; the reduction smelting bath is respectively provided with a low specific gravity slag outlet 16 and a high specific gravity slag outlet 17; the reduction smelting bath is provided with a molten iron outlet 18 at the lower part of the right end; the molten iron outlet is connected with a steel smelting furnace 19; and the device further comprises a furnace body preheating device 20 at the upper part of the suspension oxidation smelting furnace and the reduction gas gravity settling chamber.

[0036] Further, the suspension oxidation smelting furnace 1 is a vertical cylindrical material top spraying type smelting furnace composed of a membrane water cooling wall, and the top is provided with a pyrite powder and oxygen nozzle 2; the smelting furnace is an oxidation melting suspension smelting zone; the lower part of the suspension oxidation smelting furnace 1 is a suspension oxidation smelting furnace bath 9; the left side upper part of the suspension oxidation smelting furnace bath 9 is an opening of the SO2 flue 3, and the SO2 flue 3 is connected with the SO2 flue gas gravity settling chamber 4; the right side lower part of the suspension oxidation smelting furnace bath 9 is communicated with the reduction smelting bath 10; and the reduction smelting bath 10 is a rectangle.

[0037] The top of the suspension oxidation smelting furnace is provided with a vortex stirring multi-channel combustion nozzle; the lower part of the left side SO2 flue gas gravity settling chamber 4 is provided with a dust outlet 5, and the top is provided with a SO2 flue gas outlet 6; the SO2 flue gas outlet 6 is connected with a waste heat recovery device 7, and the waste heat recovery device 7 is connected with a sulfuric acid and sulfur device 8.

[0038] Further, a plurality of reducing agent inlets are staggered and arranged on both sides of the rectangular reduction smelting bath.

[0039] Further, the reduction gas outlet at the upper part of the reduction gas gravity settling chamber 13 is connected with the pyrite powder preheating device 15, and the pyrite powder preheating device 15 is connected with the pyrite powder spraying port of the suspension oxidation smelting furnace.

[0040] The method for pyrite powder suspension flash smelting by using the above device comprises the following steps:

[0041] (1) Start the furnace body preheating program of the suspension flash smelting device, spray natural gas or fuel oil from the preheating device nozzle at the upper part of the furnace body to ignite, and make the suspension smelting furnace and the reduction smelting bath reach a stable temperature of 1400-1700 DEG C in the furnace;

[0042] (2) At the initial stage of the process, open the slag outlet and the molten iron outlet on the open bath, and when the bath temperature is stable at 1400-1700°C, close the upper and lower slag outlets and the molten iron outlet;

[0043] (3) When the smelting furnace temperature is stable and reaches 1400-1700°C, start the induced draft fan of the SO2 flue gas waste heat utilization device, and after the SO2 flue gas system is stable, preheat the pyrite powder and oxygen gas burner at the top of the suspension smelting furnace, and spray the preheated pyrite powder and oxygen gas in proportion to make the pyrite powder oxidize and smelt;

[0044] (4) After the pyrite powder starts to oxidize and smelt, when the high-iron molten material in the oxidation smelting bath and the reduction smelting bath exceeds the reduction agent injection port on the reduction smelting bath, the reduction agent is injected from the reduction agent injection port to reduce and smelt; the reduction blowing process is also the process of slag-iron separation;

[0045] (5) The molten iron that has completed the reduction reaction is discharged from the molten iron outlet into the steelmaking furnace for steelmaking; the high specific gravity slag is discharged from the lower slag outlet of the reduction smelting bath for further comprehensive utilization, and the low specific gravity slag is discharged from the upper slag outlet of the reduction smelting bath for further comprehensive utilization;

[0046] (6) The high-temperature reduction flue gas of the reduction smelting is discharged from the reduction flue gas outlet above the reduction flue gas gravity settling chamber, and is in parallel heat exchange with the cold pyrite powder entering from the lower inlet of the pyrite powder preheating device to preheat the pyrite powder. The temperature of the preheated pyrite powder does not exceed 400°C, and the preheated pyrite powder is sprayed into the smelting furnace through the preheated pyrite powder+oxygen gas injection port.

[0047] The method of the above complete device for pyrite suspension smelting will be described in detail below through a specific implementation process.

[0048] Example 1:

[0049] The preheating device of the pyrite suspension smelting furnace is started to heat the whole suspension smelting device to 1400℃; the induced draft fan of the SO2 flue gas waste heat utilization device 7 is started, and after the left side SO2 flue gas system is stabilized under negative pressure, the preheated pyrite powder and oxygen are sprayed from the preheating pyrite powder and oxygen inlet 2 arranged at the top of the smelting furnace, so that the pyrite powder is burned and oxidized and smelted; the spraying amount of the preheated pyrite powder and oxygen is calculated according to the molar ratio of the molecular weight of the iron sulfide in the pyrite and the molecular weight of the oxygen; the high-temperature SO2 flue gas decomposed is sucked into the SO2 flue gas gravity settling chamber 4 through the SO2 flue 3 under micro-negative pressure, the dust removed by gravity settling is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber, and the high-temperature SO2 flue gas enters the waste heat utilization device 7 to utilize the waste heat, and then the SO2 flue gas enters the sulfuric acid device 8 to produce sulfuric acid; after the pyrite powder starts to be oxidized and smelted, the molten high-iron oxide in suspension falls and drops into the oxidizing smelting bath 9; when the high-iron molten material in the oxidizing smelting bath and the reducing smelting bath exceeds the reducing agent spraying port on the reducing smelting bath, the reducing agent spraying port on both sides of the reducing smelting bath is opened to spray the reducing agent H2 to carry out bath reduction smelting; the qualified molten iron is discharged from the molten iron outlet 18 to enter the steelmaking furnace 19 to smelt steel; the reduction blowing process is also the process of slag-iron separation, the high-specific-gravity slag is discharged from the slag outlet 17 at the lower part of the bath to be further utilized comprehensively, and the low-specific-gravity slag is discharged from the slag outlet 16 at the upper part of the bath to be further utilized comprehensively; the high-temperature flue gas after reduction smelting is discharged from the reduction flue gas outlet 14 above the reduction gas gravity settling chamber 13, and the cold pyrite powder sprayed from the lower inlet of the pyrite powder preheating device 15 is used for concurrent heat exchange to preheat the pyrite powder.

[0050] Example 2:

[0051] The temperature of the whole suspension smelting device is heated to 1700 DEG C by starting the preheating device of the pyrite suspension smelting furnace; the induced draft fan of the SO2 flue gas waste heat utilization device 7 is started, and after the negative pressure is stabilized, the preheated pyrite powder and oxygen are sprayed from the preheated pyrite powder and oxygen inlet 2 arranged at the top of the smelting furnace, so that the pyrite powder is burned and oxidized and smelted; the spraying amount of the preheated pyrite powder and oxygen is calculated according to the molar ratio of the molecular weight of the iron sulfide in the pyrite to the molecular weight of the oxygen; the high-temperature SO2 flue gas is absorbed into the SO2 flue gas gravity settling chamber 4 through the SO2 flue gas 3 under micro-negative pressure, the dust removed by gravity settling is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber, the high-temperature SO2 flue gas enters the waste heat utilization device 7 to utilize the waste heat, and then the SO2 enters the sulfuric acid device 8 to produce sulfuric acid; after the pyrite powder starts to be oxidized and smelted, the molten high-iron oxide in suspension falls and drops into the oxidizing smelting bath 9; when the high-iron molten material in the oxidizing smelting bath and the reducing smelting bath 10 exceeds the reducing agent spraying port on the reducing smelting bath, the reducing agent spraying port 12 on both sides of the reducing smelting bath is opened to spray the reducing agent carbon monoxide to carry out bath reduction smelting; the qualified molten iron is discharged from the molten iron outlet 18 to enter the steelmaking furnace 19 to smelt steel; the reduction blowing process is also the process of slag-iron separation, the high-specific-gravity slag is discharged from the slag outlet 17 at the lower part of the bath to be further utilized, and the low-specific-gravity slag is discharged from the slag outlet 16 at the upper part of the bath to be further utilized; the high-temperature flue gas after reduction smelting is discharged from the reducing flue gas outlet 14 above the reducing gas gravity settling chamber 13, and the cold pyrite powder sprayed from the lower inlet of the pyrite powder preheating device 15 is used for concurrent heat exchange to preheat the pyrite powder.

[0052] Example 3:

[0053] The preheating device of the pyrite suspension smelting furnace is started to heat the whole suspension smelting device to 1550℃; the induced draft fan of the SO2 flue gas waste heat utilization device 7 is started, and after the SO2 flue gas system is stabilized under negative pressure, the preheated pyrite powder and oxygen are sprayed from the preheating pyrite powder and oxygen inlet 2 arranged at the top of the smelting furnace to make the pyrite powder burn and oxidize and smelt; the spraying amount of the preheated pyrite powder and oxygen is calculated according to the molar ratio of the molecular weight of the iron sulfide in the pyrite and the molecular weight of the oxygen; the high-temperature SO2 flue gas is absorbed into the SO2 flue gas gravity settling chamber 4 through the SO2 flue 3 under micro-negative pressure, the dust removed by gravity settling is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber, the high-temperature SO2 flue gas enters the waste heat utilization device 7 to utilize the waste heat, and then the SO2 enters the sulfuric acid device 8 to produce sulfuric acid; after the pyrite powder starts to oxidize and smelt, the molten high-iron oxide in suspension falls and drops into the oxidizing smelting bath 9; when the high-iron molten material in the oxidizing smelting bath and the reducing smelting bath 10 exceeds the reducing agent spraying port on the reducing smelting bath, the reducing agent spraying port 12 on both sides of the reducing smelting bath 10 is opened to spray the reducing agent coal powder carried by hot air for bath reduction smelting; the qualified molten iron is discharged from the molten iron outlet 18 into the steelmaking furnace 19 for steelmaking; the reduction blowing process is also the process of slag-iron separation, the high-specific-gravity slag is discharged from the slag outlet 17 at the lower part of the bath for further comprehensive utilization, and the low-specific-gravity slag is discharged from the slag outlet 16 at the upper part of the bath for further comprehensive utilization; the high-temperature flue gas after reduction smelting is discharged from the reduction flue gas outlet 14 above the reduction gas gravity settling chamber 13, and the cold pyrite powder sprayed from the lower inlet of the pyrite powder preheating device 15 is used for concurrent heat exchange to preheat the pyrite powder.

[0054] Example 4:

[0055] The preheating device of the pyrite suspension smelting furnace is started to heat the whole suspension smelting device to 1500℃; the induced draft fan of the SO2 flue gas waste heat utilization device 7 is started, and after the SO2 flue gas system is stabilized under negative pressure, the preheated pyrite powder and oxygen are sprayed from the preheating pyrite powder and oxygen inlet 2 arranged at the top of the smelting furnace to make the pyrite powder burn and oxidize and smelt; the spraying amount of the preheated pyrite powder and oxygen is calculated according to the molar ratio of the molecular weight of the iron sulfide in the pyrite and the molecular weight of the oxygen; the high-temperature SO2 flue gas is absorbed into the SO2 flue gas gravity settling chamber 4 through the SO2 flue 3 under micro-negative pressure, the dust removed by gravity settling is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber, the high-temperature SO2 flue gas enters the waste heat utilization device 7 to utilize the waste heat, and then the SO2 enters the sulfuric acid device 8 to produce sulfuric acid; after the pyrite powder starts to oxidize and smelt, the molten high-iron oxide in suspension falls and drops into the oxidizing smelting bath 9; when the high-iron molten material in the oxidizing smelting bath and the reducing smelting bath 10 exceeds the reducing agent spraying port on the reducing smelting bath, the reducing agent spraying port 12 on both sides of the reducing smelting bath 10 is opened to spray the reducing agent natural gas to smelt the bath; the qualified molten iron is discharged from the molten iron outlet 18 to enter the steelmaking furnace 19 to smelt steel; the reduction blowing process is also the process of slag-iron separation, the high-specific-gravity slag is discharged from the slag outlet 17 at the lower part of the bath to be further utilized comprehensively, and the low-specific-gravity slag is discharged from the slag outlet 16 at the upper part of the bath to be further utilized comprehensively; the high-temperature flue gas after reduction smelting is discharged from the reduction flue gas outlet 14 above the reduction gas gravity settling chamber 13, and the cold pyrite powder sprayed from the lower inlet of the pyrite powder preheating device 15 is used for concurrent heat exchange to preheat the pyrite powder.

[0056] Example 5:

[0057] The preheating device of the pyrite suspension smelting furnace is started to heat the whole suspension smelting device to 1600 DEG C; the induced draft fan of the SO2 flue gas waste heat utilization device 7 is started, and after the SO2 flue gas system is stabilized under negative pressure, the preheated pyrite powder and oxygen are sprayed from the preheating pyrite powder and oxygen inlet 2 arranged at the top of the smelting furnace to make the pyrite powder burn and oxidize and smelt; the spraying amount of the preheated pyrite powder and oxygen is calculated according to the molar ratio of the molecular weight of the iron sulfide in the pyrite and the molecular weight of the oxygen; the high-temperature SO2 flue gas is absorbed into the SO2 flue gas gravity settling chamber 4 through the SO2 flue 3 under micro-negative pressure, the dust removed through gravity settling is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber, the high-temperature SO2 flue gas enters the waste heat utilization device 7 to utilize the waste heat, and then the SO2 enters the sulfuric acid device 8 to produce sulfuric acid; after the pyrite powder starts to oxidize and smelt, the molten high-iron oxide in suspension falls and drops into the oxidizing smelting bath 9; when the high-iron molten material in the oxidizing smelting bath and the reducing smelting bath 10 exceeds the reducing agent spraying port on the reducing smelting bath, the reducing agent spraying port 12 on both sides of the reducing smelting bath 10 is opened to spray the reducing agent LPG to carry out bath reduction smelting; the qualified molten iron is discharged from the molten iron outlet 18 to enter the steelmaking furnace 19 to smelt steel; the reduction blowing process is also the process of slag-iron separation, the high-specific-gravity slag is discharged from the slag outlet 17 at the lower part of the bath to be further utilized comprehensively, and the low-specific-gravity slag is discharged from the slag outlet 16 at the upper part of the bath to be further utilized comprehensively; the high-temperature flue gas after reduction smelting is discharged from the reducing flue gas outlet 14 above the reducing gas gravity settling chamber 13, and the cold pyrite powder sprayed from the lower inlet of the pyrite powder preheating device 15 is used for concurrent heat exchange to preheat the pyrite powder.

Claims

1. A suspension flash smelting apparatus for pyrite, characterized in that: The device is a three-furnace smelting device, with a suspension oxidation smelting furnace in the middle, an SO2 flue gas gravity settling chamber on the left side of the suspension oxidation smelting furnace, and a reduction smelting pool and a reduction flue gas gravity settling chamber above the reduction smelting pool on the right side; the self-combustion oxidation smelting of pyrite and the reduction smelting of the molten pool are a continuous process. The aforementioned suspension oxidation smelting furnace is a vertical cylindrical material top-spraying smelting furnace composed of membrane water-cooled walls. The top is equipped with pyrite powder and oxygen nozzles. The smelting furnace is an oxidation-melting suspension smelting zone. The lower part of the smelting furnace is the suspension oxidation smelting furnace molten pool. The upper left opening of the suspension oxidation smelting furnace molten pool is an SO2 flue, which connects to the SO2 flue gas gravity settling chamber. The lower right opening of the suspension oxidation smelting furnace molten pool communicates with the reduction smelting molten pool. The reduction smelting molten pool is rectangular, with an upper slag outlet and a lower slag outlet on the right side. A molten iron outlet is located at the lower right end of the reduction smelting pool, and the molten iron outlet connects to a steelmaking furnace. A reducing flue gas outlet is provided at the top of the reducing flue gas gravity settling chamber; A furnace preheating device is connected to the upper part of the suspension oxidation smelting furnace and the upper part of the reducing gas gravity settling chamber, respectively. The suspended oxidation smelting furnace has a vortex-stirring multi-channel combustion nozzle at the top; the SO2 flue gas gravity settling chamber on the left side is equipped with a dust outlet at the bottom and an SO2 flue gas outlet at the top. The SO2 flue gas outlet is connected to a waste heat recovery device, and the waste heat recovery device is connected to a sulfuric acid or sulfur production device to produce sulfuric acid or sulfur. The reducing flue gas outlet at the top of the reducing flue gas gravity settling chamber is connected to a pyrite powder preheating device, which is connected to the pyrite powder nozzle of the suspension oxidation smelting furnace.

2. The pyrite suspension flash smelting apparatus according to claim 1, characterized in that: A channel is provided between the molten pool of the suspension oxidation smelting furnace and the molten pool of the reduction smelting furnace. The cross-sectional area of ​​the channel must be matched with the output of the suspension oxidation smelting. The channel has a slope of 0 to 5 degrees from left to right. Molten high-iron oxide can only flow from the molten pool of the suspension oxidation smelting furnace to the molten pool of the reduction smelting furnace. Multiple reducing agent inlets are staggered on both sides of the rectangular reduction smelting furnace.

3. A method for suspension flash smelting of pyrite, using the suspension flash smelting apparatus for pyrite as described in any one of claims 1 to 2, characterized in that: The autogenous oxidation smelting and molten pool reduction smelting of pyrite is a continuous process, including the following steps: (1) Preheated pyrite powder and pure oxygen are injected into the smelting furnace from the burner at the top of the suspension oxidation smelting furnace. The oxidation smelting is carried out by utilizing the self-combustion property of sulfur, and the combustion temperature is controlled at 1400~1700℃. The particle size of the pyrite powder is 200~300 mesh. Lime and fluorite are added to the pyrite powder as needed to form slag. The amount of pyrite powder and oxygen in the raw materials is calculated based on the composition of iron disulfide and oxygen, and the molar ratio of the two is 1:2~1:

3. (2) The high-temperature SO2 flue gas generated by combustion is drawn into the SO2 flue gas gravity settling chamber through the SO2 flue gas duct at the upper left side of the oxidizing smelting pool under slight negative pressure. The settled dust is discharged from the dust outlet at the lower part of the SO2 flue gas gravity settling chamber. The SO2 flue gas after preliminary purification enters the SO2 flue gas waste heat utilization device from the flue gas outlet at the top of the SO2 flue gas gravity settling chamber. The SO2 flue gas after waste heat utilization is fed into the sulfuric acid or sulfur production device to produce sulfur or sulfuric acid. (3) In the suspension oxidation smelting furnace, molten high-iron oxides are suspended from the oxidation smelting zone and fall into the molten pool of the lower oxidation smelting furnace. (4) The molten high-iron oxide that falls into the lower suspension oxidation smelting furnace pool enters the left reduction smelting pool through the lower right channel of the suspension oxidation smelting pool, and is continuously reduced and smelted with the reducing agent injected from the reducing agent inlet on the reduction smelting pool. The reduction flue gas is discharged from the reduction flue gas flue above the reduction flue gas gravity settling chamber. (5) The low-density slag produced by reduction smelting is discharged from the upper slag outlet of the reduction smelting pool, the high-density slag is discharged from the lower slag outlet of the reduction smelting pool, and the molten iron is discharged from the molten iron outlet and enters the steelmaking furnace for steelmaking.

4. The suspension flash smelting method for pyrite according to claim 3, characterized in that: The SO2 flue gas entering the left SO2 flue is operated under a slight negative pressure, with the negative pressure environment provided by the induced draft fan of the waste heat utilization device; the slight negative pressure zero point is set on the SO2 flue melt pool side of the upper left side of the molten pool of the oxidation smelting furnace.

5. The suspension flash smelting method for pyrite according to claim 3, characterized in that: The aforementioned pyrite suspension flash smelting method further includes: cold pyrite powder being injected from the lower end of a preheating device outside the reducing flue gas outlet, and being preheated by exchanging heat with the high-heat reducing flue gas entering from the bottom; the preheated pyrite powder being collected and then entering the smelting furnace from the preheated pyrite powder + oxygen nozzle.

6. The suspension flash smelting method for pyrite according to claim 3, characterized in that: The reducing agent used in reducing smelting includes one of hydrogen, carbon monoxide, natural gas, LPG, or pulverized coal; the pulverized coal is injected in carrying oxygen-enriched hot air.

7. The suspension flash smelting method for pyrite according to any one of claims 3 to 6, characterized in that... Includes the following steps: (1) Start the furnace body preheating program of the suspension flash smelting device, inject natural gas or fuel oil into the furnace from the nozzle at the top of the furnace body and ignite it, so that the temperature inside the suspension smelting furnace and the reduction smelting molten pool reaches a stable 1400-1700℃. (2) At the beginning of this process, the slag outlet and molten iron outlet on the molten pool are opened. When the temperature of the molten pool stabilizes at 1400-1700℃, the upper and lower slag outlets and molten iron outlets are closed. (3) When the furnace temperature of the smelting furnace reaches 1400-1700℃, start the induced draft fan of the SO2 flue gas waste heat utilization device to provide negative pressure for SO2 flue gas. After the negative pressure is stable, inject the preheated pyrite powder and oxygen into the preheated pyrite powder and oxygen burner at the top of the smelting furnace according to the dosage ratio to oxidize and smelt the pyrite powder. (4) After the pyrite powder begins to be oxidized and smelted, when the molten high-iron material in the oxidized smelting pool and the reduced smelting pool exceeds the reducing agent nozzle on the reduced smelting pool, the reducing agent is injected from the reducing agent nozzle to carry out the reduced smelting; the process of reduced blowing is also the process of slag and iron separation. (5) The molten iron that has completed the reduction reaction is discharged from the molten iron outlet and fed into the steelmaking furnace for steelmaking; the high specific gravity slag is discharged from the lower slag outlet of the molten pool, and the low specific gravity slag is discharged from the upper slag outlet of the molten pool. (6) The high-temperature reducing flue gas from the reduction smelting is discharged from the flue gas outlet at the top of the reducing flue gas gravity settling chamber and is preheated by the cold pyrite powder entering from the bottom inlet of the pyrite powder preheating device. The temperature of the preheated pyrite powder does not exceed 400℃. The preheated pyrite powder is then injected into the smelting furnace through the preheated pyrite powder + oxygen nozzle.

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