Ausmelt furnace top and bottom composite blowing method

Abstract

The present invention belongs to the field of copper smelting in Ausmelt furnaces, and particularly relates to a top-bottom combined blowing method for Ausmelt furnaces. Aiming at the defects such as short service life of the top blowing lance, uneven heat transfer in the molten bath, and poor fluidity of the molten slag during the smelting process of Ausmelt furnaces, the present invention provides a top-bottom combined blowing method. Three or four bottom blowing lances are provided. Both the top blowing lance and the bottom blowing lance are of a three-layer jacket structure. The innermost layer is gas, the middle layer is oxygen-rich gas, and the outermost layer is CO2 gas. The top blowing and bottom blowing are carried out simultaneously, increasing the fluidity of the melt in the molten bath, reducing the heat loss of the top blowing lance, the content of Fe3O4 in the molten slag, and the viscosity of the molten slag, and significantly improving the production situation.

Description

Technical Field

[0001] The invention belongs to the field of copper smelting of Ausmelt furnaces, and in particular relates to a top and bottom composite blowing method of Ausmelt furnaces. Background Art

[0002] Ausmelt furnace technology is also known as "Siro" lance top-blowing submerged smelting technology, that is, the lance is vertically immersed in the slag layer. The lance structure consists of four specially designed concentric sleeves: the innermost layer is pulverized coal and air (coal-carrying air); the second layer is oxygen; the third layer is air (lance air); the outermost layer is sleeve air (sleeve air) that protects the third sleeve wall, and is also used to assist the combustion of sulfur and other combustible components (mainly CO) in the combustion flue gas generated by smelting in the furnace. The concentrate is dried, granulated and kneaded in the kiln, and is directly added to the furnace through the furnace top charging port. The lance is inserted from the top of the furnace into the melt in the vertically placed cylindrical furnace. Air (or oxygen-enriched air) and fuel (oil, natural gas or pulverized coal) are sprayed into the melt from the end of the lance, creating a violently churning molten pool surface in the furnace. At this time, the furnace charge is directly added to the churning molten pool from the top charging port, falls to the molten pool surface in a free fall, and is stirred, mixed and melted by the airflow.

[0003] Unlike oxygen top-blown autothermal melting furnace spray guns and Mitsubishi spray guns that do not insert the melt and only spray 500mm~900mm above the melt, the end of the Silo spray gun used in the Ausmelt furnace is inserted 200mm~300mm below the slag surface and blows in the slag layer. In addition to being violently stirred by the spraying airflow, the melt also produces a rotational motion. Since the outlet pressure of the Silo spray gun is low, only 50kPa~250kPa, the power consumption is less.

[0004] The current Ausmelt furnace has the following disadvantages:

[0005] 1. The outer wall of the Sero spray gun must always maintain a layer of solid slag to prevent the gun wall from melting in order to operate normally, so the spray gun wall needs to be sufficiently cooled. At present, the methods to extend the life of the spray gun include improving the spray gun material, adding water or coal powder to the reaction air, and controlling the heat transfer of the spray gun. However, the biggest disadvantage of the Ausmelt furnace is still its short operating life. At present, by changing the internal structure of the spray gun, a spiral blade cyclone is added to the annular air channel to strengthen the air disturbance and improve the convective heat transfer coefficient, so as to achieve the purpose of enhancing the heat transfer and reducing the temperature of the spray gun wall. However, the cost is that the spray gun blowing air pressure is greatly reduced, which can easily cause the slag layer to be "not blown through", that is, the reaction is not sufficient, causing the physical and chemical properties of the slag in the molten pool to deteriorate, affecting production efficiency.

[0006] 2. The coal powder sprayed by the Ausmelt spray gun burns quickly, resulting in uneven heat transfer in the molten pool. The molten pool temperature near the spray gun is high, and the molten pool temperature near the furnace wall is low, resulting in a large temperature gradient, which is not conducive to the reduction process of Fe3O4 in the molten pool (the operation requirements of the Ausmelt furnace are a small temperature gradient, that is, uniform temperature distribution). It is easy to deteriorate the slag phase composition, which makes the slag fluidity worse, resulting in foamy slag, slag surge and other phenomena, damaging the furnace lining and spray gun, and then leading to problems such as difficulty in separating slag from metal and difficulty in slag discharge at the weir, which seriously affect production.

[0007] 3. The large temperature gradient leads to untimely and inaccurate feedback on the actual temperature of the furnace, extremely high requirements for operation, low tolerance for production operation, and frequent production accidents such as substandard production;

[0008] 4. The spray gun of Ausmelt furnace spraying uses coal powder / natural gas / diesel as insulation, which is more expensive, while Mitsubishi spray guns can use heavy oil as fuel, which is less expensive.

[0009] In summary, the current Ausmelt furnace must ensure sufficient enhanced heat transfer to form a solid slag layer outside the gun wall, and fully reduce the pressure loss in the lance to reduce costs. Summary of the invention

[0010] In view of the problems existing in the prior art, the present invention provides an Ausmelt furnace top and bottom composite blowing method, comprising the following contents: a top blowing lance and a bottom blowing lance are used to blow the molten pool simultaneously; the bottom blowing lance is a three-layer jacket structure, the innermost layer is a by-product gas, including at least one of blast furnace gas, converter gas, and coke oven gas, and the main components are CO, H2, and CH4; the middle layer is an oxygen-rich gas, including oxygen or oxygen-rich air with an oxygen content of 21% to 25%; the outermost layer is CO2 gas. The bottom blowing lances are symmetrically distributed at the bottom of the furnace according to the center, and the number is preferably 3 or 4.

[0011] For an Ausmelt furnace with a charge (including ore and auxiliary materials) of 150t / h~200t / h, the single bottom blowing lance is set as follows:

[0012] The total pressure of the bottom blowing gun is 135kPa~172kPa, and the total air flow rate is 2500Nm 3 / h~3400 Nm 3 / h; the innermost gas back pressure is 20kPa~30kPa, and the gas flow rate is 400Nm 3 / h~600Nm 3 / h; the back pressure of the oxygen-rich gas in the middle layer is 68kPa~90kPa, and the gas flow rate is 1500Nm 3 / h~2000Nm 3 / h; the outermost CO2 gas back pressure is 47kPa~52kPa, and the gas flow rate is 600Nm 3 / h~800Nm 3 / h.

[0013] The above bottom blowing method can be combined with the existing top blowing method (coal powder + oxygen / air) for blowing, or combined with the following preferred top blowing method for blowing. Preferably, the top blowing lance is also a three-layer jacket structure, which is the same as the bottom blowing lance structure, and the gas passing through each layer of the top blowing lance is also the same as the gas passing through each layer of the bottom blowing lance. For an Ausmelt furnace with a charge (including ore and auxiliary materials) of 150t / h~200t / h, the top blowing lance is set as follows:

[0014] The total pressure of the top-blowing spray gun is 300kPa~600kPa, and the total air flow rate is 2000Nm 3 / h~6000Nm 3 / h. The innermost gas back pressure is 100kPa~200kPa, and the gas flow rate is 560Nm 3 / h~1260Nm 3 / h; the back pressure of oxygen-rich gas in the middle layer is 158kPa~258kPa, and the gas flow rate is 1000Nm 3 / h~3500Nm 3 / h; the outermost CO2 gas back pressure is 42kPa~142kPa, and the gas flow rate is 440Nm 3 / h~1240Nm 3 / h.

[0015] The top-blowing lance and the bottom-blowing lance of the present invention both adopt a three-layer sheath structure, and are combined with a top-bottom composite blowing method in which the innermost layer of the lance is coal gas, the middle layer is oxygen-rich gas, and the outermost layer is CO2 gas. During the Ausmelt furnace smelting process, complete gas blowing can be achieved, and pulverized coal is no longer blown in the lance.

[0016] The above-mentioned Ausmelt furnace top and bottom composite blowing method includes the following specific contents:

[0017] (1) Adding the charge consisting of copper concentrate powder and auxiliary materials into the furnace through the upper charging port of the Ausmelt furnace;

[0018] (2) After lowering the top-blowing lance to below the slag surface, adjust the tuyere pressures of the top-blowing and bottom-blowing lances to spray the molten pool simultaneously;

[0019] (3) When the copper matte grade reaches 58%~62%, record the top-blowing lance outer wall temperature and molten pool temperature distribution, and take slag samples and copper matte for analysis.

[0020] Among them, the temperature difference between the center temperature and the side wall temperature of the slag in the molten pool does not exceed 160°C, the average content of Fe3O4 in the slag is not higher than 13.2%, the concentration difference between the center and the side wall does not exceed 7%, and the viscosity of the slag does not exceed 0.9 Pa·s.

[0021] The beneficial effects of the present invention are as follows:

[0022] This design selects top blowing and bottom blowing composite blowing, introduces additional disturbing swirl from the bottom of the slag metal fluid, and significantly enhances the heat transfer process. Under the same air flow rate, the swirl fluid flows a longer distance than the axial flow fluid, the local fluid velocity near the gun wall increases, and the convective heat transfer coefficient also increases, which accelerates the transfer of heat from the gun wall surface to the melt. The turbulent flow and turbulent kinetic energy generated by the swirl increase, and the turbulent heat transfer will also increase. The swirl center generated near the bottom blowing hole will help to strengthen the fluid turbulence away from the gun wall and reduce the thermal resistance of the laminar bottom layer near the gun wall. At the same time, multiple dispersed swirl centers are conducive to strengthening the molecular diffusion effect, so that the colder air in the spray gun replaces the hotter air at the outer wall of the spray gun. The present invention is equipped with 3 bottom blowing spray guns or 4 bottom blowing spray guns. When the number of spray guns exceeds 4, the cost is higher, and the refractory brick structure at the bottom of the furnace is prone to rupture and damage, resulting in melt penetration.

[0023] The spray gun of the present invention uses a three-layer jacket structure, the innermost layer is the by-product gas, mainly blast furnace gas, converter gas or coke oven gas, the main components are CO, H2 and CH4, the main function is to provide combustion heat and reduce the heat supply pressure of the top-blowing spray gun. The second layer is combustion-supporting air or pure oxygen, which can be pre-mixed into oxygen-enriched air (O2 greater than 21%). The outermost layer is CO2 gas, which is a stirring gas. On the one hand, CO2 can effectively remove excess carbon in the molten pool, especially in the copper matte. The reaction is an endothermic reaction, which is easy to control and stabilize the temperature of the molten pool, and effectively inhibit the boiling of the molten pool slag, thereby reducing the occurrence of melting loss of the top-blowing spray gun caused by the boiling of the slag; on the other hand, its stirring effect is stronger than that of air, close to the effect of argon gas, but at a lower cost, and can also play a role in cooling and protecting the spray gun jacket. Moreover, CO2 can react with unreacted coal in the molten pool to generate CO. The generated CO can further promote the reduction of Fe3O4 in the molten pool, reduce the content of Fe3O4 in the slag, thereby reducing the viscosity of the slag, increasing the fluidity of the melt in the molten pool, and improving production conditions.

[0024] The method of the present invention can strengthen the molten pool blowing and heat transfer, increase the molten pool turbulence, achieve efficient protection of the spray gun, make the slag react more fully, reduce the temperature gradient and Fe3O4 concentration gradient in the molten pool, avoid foamy slag, slag surge and other phenomena, reduce damage to the furnace lining and spray gun, and solve the problems that seriously affect production such as the difficulty in separating slag from gold, the difficulty in slag discharge at the weir, and the large error in operation feedback. The use of side blowing can also achieve the effect of this design. The outermost layer of CO2 of the bottom blowing spray gun can be replaced with a mixture of O2 and Ar, which can also achieve some of the beneficial effects of this design. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the Ausmelt furnace top and bottom composite blowing.

[0026] Figure 2 This is a schematic diagram of the three bottom blowing lances installed at the bottom of the Ausmelt furnace.

[0027] Figure 3 This is a schematic diagram of the four bottom blowing lances installed at the bottom of the Ausmelt furnace.

[0028] Figure 4 It is a schematic diagram of the three-layer jacket structure of the Ausmelt furnace spray gun. DETAILED DESCRIPTION

[0029] The technical scheme of the present invention is clearly and completely described in conjunction with the embodiments and the accompanying drawings. It should be noted that the embodiments described in the present invention are only used to further explain and illustrate, rather than to limit the scope of application. Based on the present invention, all other schemes obtained by those skilled in the art without making creative work belong to the protection scope of the present invention.

[0030] The present invention adopts one top-blowing spray gun. In the embodiment, the gas supply settings of the top-blowing spray gun and the bottom-blowing spray gun are based on the following charge dosage. When the charge dosage changes during production, the gas supply of each layer of the top-blowing spray gun and the bottom-blowing spray gun can be adjusted according to the specific production situation to meet the production needs.

[0031] The basic process of copper smelting in the Ausmelt furnace in the embodiment is as follows:

[0032] (1) The ore used in the embodiment is copper sulfide ore, and the main components and contents of the ore are Cu: 22%~25%, S: 26%~31%, Fe: 25%~30%, SiO2: 5%~7%, and CaO: 1.5%~3%. The ore and auxiliary materials (coal, river sand, etc.) are added to the furnace through the Ausmelt furnace charging port via a conveyor belt. The ore feeding rate is 150t / h~200t / h. Lump coal with a particle size of 30mm~200mm (of which 40mm~100mm accounts for 90%) is added to the furnace via a conveyor belt, and the coal consumption is 4t / h~6t / h. River sand with a particle size of 1mm~3mm (as flux, SiO2 content of more than 97%) is added to the furnace via a conveyor belt, and the amount of flux added is 10t / h~20t / h. Lump coal, flux and ore are added to the Ausmelt furnace separately without premixing.

[0033] (2) After lowering the top-blowing lance below the slag surface, there is no need to wait for the charge to melt. The top-blowing Silo lance can be directly immersed in the molten pool. The tuyere pressure of the top-blowing lance is adjusted to spray the molten pool. At the same time, the bottom-blowing lance is pressurized to spray the molten pool. The entire charging and blowing process is continuous.

[0034] (3) When the copper matte grade reaches 58%~62%, record the top-blowing lance outer wall temperature and melt temperature distribution, take slag samples and copper matte for analysis, release a portion of copper matte and slag through the weir to enter the subsequent process, and maintain the molten pool height at about 2000mm. The slag viscosity is tested in accordance with the YB / T 185-2017 standard. The copper matte grade is tested in accordance with the YS∕T 483-2022 standard. The copper content is used to indicate the copper matte grade. The test is conducted at regular intervals. The test results have a lag, and the test interval can be adjusted according to the actual situation.

[0035] The schematic diagram of the Ausmelt furnace top and bottom composite blowing of the present invention is as follows Figure 1 As shown, the schematic diagram of setting three spray guns at the bottom of the furnace is as follows Figure 2 As shown, the schematic diagram of setting 4 spray guns at the bottom of the furnace is as follows Figure 3 As shown, the spray gun structure is as follows Figure 4 shown.

[0036] The amount of charge added and the setting conditions of the top-blowing lance in Examples 1 to 4 are the same. The specific amount of charge is as follows: 150t / h of ore, 5t / h of coal, and 15t / h of river sand. The top-blowing lance is set as follows: the total pressure of the top-blowing lance is 450kPa, and the total gas supply is 4500Nm 3 / h; inner gas back pressure is 150kPa, gas supply volume is 1000Nm 3 / h; the back pressure of the oxygen-rich gas in the middle layer is 200kPa, and the gas supply volume is 2700Nm 3 / h; the outermost CO2 gas back pressure is 100kPa, and the gas supply volume is 800Nm 3 / h. When the copper matte grade reaches 58%, the top-blowing lance outer wall temperature and melt temperature distribution are recorded, and slag samples and copper matte are taken for analysis.

[0037] Example 1: 1 top blowing + 3 bottom blowing spray guns are used.

[0038] The total pressure of a single bottom blowing spray gun is 135kPa, and the total air flow rate is 2500Nm 3 / h; the innermost blast furnace gas back pressure is 20kPa, and the gas flow rate is 400Nm 3 / h; intermediate layer oxygen back pressure 68kPa, gas flow 1500Nm 3 / h; outermost CO2 gas back pressure 47kPa, gas flow 600Nm 3 / h.

[0039] Example 2: 1 top blowing + 3 bottom blowing spray guns are used.

[0040] The total pressure of a single bottom blowing spray gun is 155kPa, and the total air flow rate is 3050 Nm 3 / h; the innermost converter gas back pressure is 27kPa, and the gas flow rate is 550Nm 3 / h; the oxygen-rich gas in the middle layer is oxygen, the back pressure is 78kPa, and the gas flow rate is 1800Nm 3 / h; outermost CO2 gas back pressure 50kPa, gas flow 700Nm 3 / h.

[0041] Example 3: 1 top blowing + 4 bottom blowing spray guns are used.

[0042] The total pressure of a single bottom blowing spray gun is 155kPa, and the total air flow rate is 3050 Nm 3 / h; the innermost converter gas back pressure is 27kPa, and the gas flow rate is 550Nm 3 / h; the oxygen-rich gas in the middle layer is oxygen, the back pressure is 78kPa, and the gas flow rate is 1800Nm 3 / h; outermost CO2 gas back pressure 50kPa, gas flow 700Nm 3 / h. Other conditions are the same as those in Example 2.

[0043] Example 4: 1 top blowing + 4 bottom blowing spray guns are used.

[0044] The total pressure of a single bottom blowing spray gun is 172kPa, and the total air flow rate is 3400 Nm 3 / h; the innermost coke oven gas back pressure is 30kPa, and the gas flow rate is 600Nm 3 / h; the oxygen-rich gas in the middle layer is oxygen, the back pressure is 90kPa, and the gas flow rate is 2000Nm 3 / h; outermost CO2 gas back pressure 52kPa, gas flow 800Nm 3 / h.

[0045] The amount of charge added and the bottom blowing spray gun setting conditions in Examples 5 and 6 are the same. The specific amount of charge is as follows: 200t / h of ore, 6t / h of coal, and 20t / h of river sand. The single bottom blowing spray gun is set as follows: the total pressure of a single bottom blowing spray gun is 155kPa, and the gas flow rate is 3050 Nm 3 / h; the innermost converter gas back pressure is 27kPa, and the gas flow rate is 550Nm 3 / h; the oxygen-rich gas in the middle layer is oxygen, the back pressure is 78kPa, and the gas flow rate is 1800Nm 3 / h; outermost CO2 gas back pressure 50kPa, gas flow 700Nm 3 / h. When the copper matte grade reaches 62%, the top-blowing lance outer wall temperature and melt temperature distribution are recorded, and slag samples and copper matte are taken for analysis.

[0046] The total pressure of the top-blowing spray gun is 300kPa~600kPa, and the total air flow rate is 2000Nm 3 / h~6000Nm 3 / h. The innermost gas back pressure is 100kPa~200kPa, and the gas flow rate is 560Nm 3 / h~1260Nm 3 / h; the back pressure of oxygen-rich gas in the middle layer is 158kPa~258kPa, and the gas flow rate is 1000Nm 3 / h~3500Nm 3 / h; the outermost CO2 gas back pressure is 42kPa~142kPa, and the gas flow rate is 440Nm 3 / h~1240Nm 3 / h.

[0047] Example 5: 1 top blowing + 3 bottom blowing spray guns are used.

[0048] The total pressure of the top-blowing spray gun is 300kPa, and the total air flow rate is 2000Nm 3 / h. The innermost gas back pressure is 100kPa, and the gas flow rate is 560Nm 3 / h; the back pressure of oxygen-rich gas in the middle layer is 158kPa, and the gas flow rate is 1000Nm 3 / h; the outermost CO2 gas back pressure is 42kPa, and the gas flow rate is 440Nm 3 / h.

[0049] Example 6: 1 top blowing + 4 bottom blowing spray guns are used.

[0050] The total pressure of the top-blowing spray gun is 600kPa, and the total air flow rate is 6000Nm 3 / h. The innermost gas back pressure is 200kPa, and the gas flow rate is 1260Nm 3 / h; the back pressure of oxygen-rich gas in the middle layer is 258kPa, and the gas flow rate is 3500Nm 3 / h; the outermost CO2 gas back pressure is 142kPa, and the gas flow rate is 1240Nm 3 / h.

[0051] Comparative Example 1 Only one top-blowing spray gun was used for spraying, and no bottom-blowing spraying was used.

[0052] The total pressure of the top-blowing spray gun is 450kPa, and the total air supply is 4500Nm 3 / h; inner gas back pressure is 150kPa, gas supply volume is 1000Nm 3 / h; the back pressure of the oxygen-rich gas in the middle layer is 200kPa, and the gas supply volume is 2700Nm 3 / h; the outermost CO2 gas back pressure is 100kPa, and the gas supply volume is 800Nm 3 / h. Other conditions are the same as those in Example 1.

[0053] Comparative Example 2: 1 top blowing + 3 bottom blowing spray guns are used, and the bottom blowing is without CO2.

[0054] The top-blowing spray gun is set as follows: the total pressure of the top-blowing spray gun is 450kPa, and the total air supply is 4500Nm 3 / h; inner gas back pressure is 150kPa, gas supply volume is 1000Nm 3 / h; the back pressure of the oxygen-rich gas in the middle layer is 200kPa, and the gas supply volume is 2700Nm 3 / h; the outermost CO2 gas back pressure is 100kPa, and the gas supply volume is 800Nm 3 / h.

[0055] The outermost layer of the bottom blowing gun has no CO2, and all of them are air-blowing. The settings of a single bottom blowing gun are as follows: the total pressure of the gun is 135kPa, and the total air supply flow is 2500Nm 3 / h; the innermost blast furnace gas back pressure is 20kPa, and the gas flow rate is 400Nm 3 / h; intermediate layer oxygen back pressure 68kPa, gas flow 1500Nm 3 / h; the outermost air back pressure is 47kPa, and the air flow rate is 600Nm 3 / h. Other conditions are the same as those in Example 1.

[0056] Comparative Example 3: 1 common top blowing + 4 bottom blowing spray guns were used.

[0057] The common top-blowing spray gun has a 4-layer jacket structure: the innermost layer is pulverized coal and air (coal-carrying air); the second layer is oxygen; the third layer is air (spray gun air); the outermost layer is sleeve air (sleeve air) that protects the third layer of copper wall. The parameters of the common top-blowing spray gun are: the total pressure of the top-blowing spray gun is 850kPa, and the total air supply flow rate is 3400Nm 3 / h. The innermost layer of coal powder injection has a particle size of 0.1~6mm and an injection volume of 4t / h. The coal-carrying air gauge pressure is 150kPa and the air supply flow rate is 600Nm 3 / h; the second layer oxygen gauge pressure is 300kPa, and the gas flow rate is 1200Nm 3 / h; the third layer air spray gun wind gauge pressure is 200kPa, the air flow rate is 800Nm 3 / h; the outermost sleeve air gauge pressure is 200kPa, and the air flow rate is 800Nm 3 / h.

[0058] The single bottom blowing spray gun is set as follows: the total pressure of the spray gun is 135kPa, and the total air flow rate is 2500Nm 3 / h; the innermost blast furnace gas back pressure is 20kPa, and the gas flow rate is 400Nm 3 / h; intermediate layer oxygen back pressure 68kPa, gas flow 1500Nm 3 / h; outermost CO2 gas back pressure 47kPa, gas flow 600Nm 3 / h. Other conditions are the same as those in Example 1.

[0059] The temperature conditions of key parts and the slag conditions in the molten pool in each embodiment and comparative example are shown in Table 1, wherein the average content of Fe3O4 refers to the average content of Fe3O4 in the slag, and the Fe3O4 concentration difference refers to the concentration difference of Fe3O4 in the slag at the center and the slag at the side wall.

[0060] Table 1 Temperature of key parts and slag in the molten pool in each embodiment and comparative example

[0061] Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Top blowing gun outer wall temperature ℃ 1530 1430 1577 1380 1363 1330 1344 1351 1358 Molten pool center temperature ℃ 1380 1350 1421 1343 1349 1353 1366 1340 1373 Side wall temperature ℃ 1105 1165 1240 1185 1201 1209 1215 1194 1220 Temperature difference between center and side wall℃ 275 185 181 158 148 144 151 146 153 <![CDATA[Average content of Fe3O4 %]]> 17.3 15.2 14.8 13.2 12.2 11.8 12.9 12.4 13.1 <![CDATA[Percentage of Fe3O4 concentration difference]]> 8.7 7.5 7.1 6.9 6.3 5.6 5.9 6.4 6.5 Slag viscosity Pa·s 0.994 0.917 0.900 0.887 0.811 0.785 0.802 0.821 0.833

[0062] From Table 1, we can see that:

[0063] 1. It can be seen from Examples 1 and 2 that when there are three bottom blowing lances, the bottom blowing gas supply intensity increases, the heat transfer efficiency of the molten pool increases, the temperature difference between the center and the side wall decreases, the average content of Fe3O4 decreases, the concentration difference between the center and the side wall decreases, and the slag viscosity decreases;

[0064] 2. It can be seen from Examples 2 and 3 that when the number of bottom blowing spray guns is increased from 3 to 4 and the air supply conditions of the spray guns remain unchanged, the above effect is further significantly improved;

[0065] 3. It can be seen from Examples 3 and 4 that when there are four bottom-blowing lances and the gas supply intensity is further increased, the molten pool boils violently, causing sputtering corrosion on the outer wall of the top-blowing lance, causing the outer wall temperature to increase. At the same time, the valuable components in the slag are enhanced due to the boiling flow, which causes FeO in the slag to be overoxidized, and the Fe3O4 content increases, resulting in an increase in the slag viscosity and an increase in the temperature difference between the center and the side wall;

[0066] 4. It can be seen from Examples 5 and 6 that when there are 3 and 4 bottom-blowing lances, when the strength of the top-blowing lances decreases or increases, the center temperature and the side wall temperature of the molten pool decrease or increase at the same time. Too high a center temperature can easily cause a high temperature gradient, which is not conducive to the reduction of Fe3O4 and worsens the slag viscosity.

[0067] 5. From Comparative Example 1, it can be seen that when there is no bottom blowing, the heat transfer efficiency of the molten pool is low, the temperature difference between the center and the side wall is large, the average concentration of Fe3O4 is high, the concentration difference between the center and the side wall is large, and the slag viscosity is high;

[0068] 6. From Comparative Example 2, it can be seen that when bottom blowing is added but there is no CO2 gas in the bottom blowing, although the situation is improved compared with the case without bottom blowing, the temperature difference between the center and side walls of the slag, the average content of Fe3O4, the concentration difference between the center and side walls of Fe3O4, the viscosity of the slag, etc. are still large compared with Examples 1 to 4.

[0069] 7. It can be seen from Comparative Example 3 that when a general top-blowing spray gun is used for spraying and bottom blowing is added, the heat brought in by the top blowing is too high, the temperatures of the center and side walls of the molten pool are both high, and the temperature difference is large. Compared with Example 4, the temperature of the outer wall of the spray gun is too high, and the average Fe3O4 content, the concentration difference between the center and side walls of Fe3O4, and the slag viscosity are larger.

Claims

1. An Ausmelt furnace top and bottom composite blowing method, characterized in that: The top-blowing lance and the bottom-blowing lance are used to blow the molten pool at the same time; the bottom-blowing lance is a three-layer jacket structure, the innermost layer is coal gas, the middle layer is oxygen-rich gas, and the outermost layer is CO2 gas; the top-blowing lance is also a three-layer jacket structure, the innermost layer is coal gas, the middle layer is oxygen-rich gas, and the outermost layer is CO2 gas; By adopting the above-mentioned lance structure and top-bottom composite blowing method, the smelting process of the Ausmelt furnace can be completely blown with gas, and pulverized coal is no longer sprayed in the lance.

2. The Ausmelt furnace top and bottom composite blowing method according to claim 1, characterized in that: The coal gas in the innermost layer of the top-blowing spray gun and the bottom-blowing spray gun is a by-product coal gas, including at least one of blast furnace gas, converter gas, and coke oven gas, and its main components are CO, H2, and CH4; the oxygen-rich gas includes oxygen or oxygen-enriched air with an oxygen content of 21% to 25%.

3. The Ausmelt furnace top and bottom composite blowing method according to claim 1, characterized in that: The number of the bottom blowing spray guns is no more than 4 and they are symmetrically distributed at the bottom of the furnace.

4. The Ausmelt furnace top and bottom composite blowing method according to claim 1, characterized in that: For an Ausmelt furnace with a charge capacity of 150t / h~200t / h, the total pressure of a single bottom-blowing lance is 135kPa~172kPa, and the total gas flow rate is 2500Nm 3 / h~3400 Nm 3 / h; the furnace charge includes mineral material, sand and coal, and the feeding speed is 10t / h~20t / h for sand and 4t / h~6t / h for coal.

5. The Ausmelt furnace top and bottom composite blowing method according to claim 1, characterized in that: For an Ausmelt furnace with a charge capacity of 150t / h~200t / h, the innermost gas back pressure of a single bottom-blowing lance is 20kPa~30kPa, and the gas flow rate is 400Nm 3 / h~600Nm 3 / h; the back pressure of the oxygen-rich gas in the middle layer is 68kPa~90kPa, and the gas flow rate is 1500Nm 3 / h~2000Nm 3 / h; the outermost CO2 gas back pressure is 47kPa~52kPa, and the gas flow rate is 600Nm 3 / h~ 800Nm 3 / h.

6. The Ausmelt furnace top and bottom composite blowing method according to claim 1, characterized in that: The total pressure of the top-blowing spray gun is 300kPa~600kPa, and the total air flow rate is 2000Nm 3 / h~6000Nm 3 / h.

7. The Ausmelt furnace top and bottom composite blowing method according to claim 1, characterized in that: For Ausmelt furnaces with a charge capacity of 150t / h~200t / h, the innermost gas back pressure of the top-blowing lance is 100kPa~200kPa, and the gas flow rate is 560Nm 3 / h~1260Nm 3 / h; the back pressure of the oxygen-rich gas in the middle layer is 158kPa~258kPa, and the gas flow rate is 1000Nm 3 / h~3500Nm 3 / h; the outermost CO2 gas back pressure is 42kPa~142kPa, and the gas flow rate is 440Nm 3 / h~ 1240Nm 3 / h.

8. An Ausmelt furnace top and bottom composite blowing method according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Adding a charge consisting of copper ore and auxiliary materials into the furnace of an Ausmelt furnace; (2) Lower the top-blowing lance to below the slag surface, adjust the tuyere pressure of the top-blowing and bottom-blowing lances, and spray the molten pool simultaneously; (3) When the copper matte grade reaches 58%~62%, record the top-blowing lance outer wall temperature and molten pool temperature distribution, and take slag samples and copper water for analysis.

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