A detection method, detection mechanism and detection device for alkali removal capacity of blast furnace slag desulfurization

Abstract

The application discloses a detection method, a detection mechanism and a detection device for the desulfurization and alkali discharge capacity of blast furnace slag, and the detection method comprises the following steps: S1. Preparing sulfur-containing iron: taking on-site pig iron and FeS reagent as raw materials, and preparing sulfur-containing iron by casting after smelting; S2. Preparing alkali-containing slag: taking the components of on-site blast furnace slag as a benchmark, weighing raw material reagents to prepare alkali-containing slag, heating and melting, and preparing the alkali-containing slag after cooling, and detecting the alkali metal content in the alkali-containing slag; S3. Carrying out slag-gold reaction: placing the alkali-containing slag and the sulfur-containing iron in the detection mechanism of the detection device, heating and reacting, cooling after the reaction is completed, separating slag and gold, obtaining final slag and iron, and detecting the alkali metal content in the final slag and the sulfur content in the iron. The application provides a method for simulating the slag-gold reaction in a blast furnace to measure the desulfurization and alkali discharge capacity of blast furnace slag, and the desulfurization and alkali discharge capacity of the slag is quantitatively evaluated according to the sulfur content in the molten iron after the reaction and the sodium oxide and potassium oxide content in the final slag, and the method is simple and has good reproducibility.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace ironmaking, in particular to a detection method, detection mechanism and detection device for the desulfurization and alkali removal capacity of blast furnace slag. BACKGROUND

[0002] The blast furnace is the main method for producing molten iron, and the raw materials such as iron ore, sintered ore, pellet ore, coke and coal can all bring in impurities such as sulfur and alkali metals. Among them, sulfur mainly enters the molten iron during the reduction of iron ore, and has a great impact on the quality of steel during the molten iron steelmaking stage. In order to avoid the adverse effects of sulfur on subsequent steelmaking, it is necessary to remove sulfur from the molten iron in the blast furnace in advance, therefore, desulfurization in blast furnace ironmaking is an important requirement for producing qualified molten iron. In addition, due to the presence of various forms of alkali metal compounds such as potassium and sodium compounds in the raw materials of the blast furnace, after being reduced in the blast furnace, the metal vapor rises with the coal gas, and with the decrease of temperature, it is oxidized and attached to the surface of the charge, forming the enrichment of alkali metals in the blast furnace, causing damage to the coke, expansion of the sintered ore, pulverization of the sintered ore, formation of the nodule on the furnace wall and corrosion of the refractory material, etc., affecting the normal production of the blast furnace.

[0003] In the actual production process, due to the large amount of raw materials used in blast furnace ironmaking and the relatively stable source, the cost of low-impurity raw materials is too high, so it is not possible to reduce the total amount of sulfur and alkali metals in the raw materials by adjusting the grade of the raw materials. At present, the use of blast furnace slag to remove sulfur from molten iron and remove alkali metals from the blast furnace is the only feasible way. However, with the increasingly stringent requirements for reducing CO2 emissions in the blast furnace ironmaking industry in recent years, the iron grade in the raw materials is increasing, and the slag quantity is decreasing, which increases the burden of slag desulfurization and alkali removal, making it more urgent to improve the desulfurization and alkali removal capacity of the blast furnace slag by changing the properties of the slag and the operating conditions. At present, many researchers try to evaluate the desulfurization and alkali removal capacity of the blast furnace slag through experimental research, in order to achieve the purpose of providing guidance for actual blast furnace production. The patent application file with publication number CN102279203A proposes a method for evaluating the desulfurization and alkali removal capacity of the slag by using gas-slag equilibrium technology to determine the potassium sulfide capacity of the blast furnace slag. However, this method measures the capacity of dissolved sulfur and potassium in the slag under ideal conditions, without considering the reaction conditions of the slag in the actual blast furnace and the influence of the kinetics of the reaction not reaching equilibrium, and also does not include the behavior of sodium in the blast furnace, therefore, this method does not completely match the desulfurization and alkali removal capacity of the blast furnace slag in the actual production process. SUMMARY

[0004] The purpose of the present application is to provide a detection method, detection mechanism and detection device for the desulfurization and alkali removal capacity of blast furnace slag, which can simulate the desulfurization and alkali removal behavior of the blast furnace slag in the actual production process of blast furnace ironmaking to the greatest extent, and the conclusions obtained are more consistent with the actual production process of blast furnace ironmaking, and the desulfurization and alkali removal capacity of the blast furnace slag is more intuitive and accurate.

[0005] In a first aspect, the present application provides a method for detecting the desulfurization and alkali removal capacity of blast furnace slag, which adopts the following technical scheme:

[0006] A method for detecting the desulfurization and alkali removal capacity of blast furnace slag, specifically comprising the following steps:

[0007] S1. Preparing sulfur-containing iron: taking on-site pig iron and FeS reagent as raw materials for preparing the sulfur-containing iron, weighing the raw materials based on the set sulfur content of the sulfur-containing iron, and casting after melting the raw materials to prepare the sulfur-containing iron;

[0008] S2. Preparing alkali-containing slag: weighing raw material reagents to prepare alkali-containing slag based on the composition of on-site blast furnace slag, heating to melt the raw material reagents of the alkali-containing slag, and preparing the alkali-containing slag after cooling, and detecting the alkali metal content in the alkali-containing slag;

[0009] S3. Carrying out slag-gold reaction: placing the prepared sulfur-containing iron and alkali-containing slag in the detection mechanism of the detection device, carrying out temperature rising reaction, cooling after reaction, separating slag and gold, obtaining final slag and iron, and detecting the alkali metal content in the final slag and the sulfur content in the iron.

[0010] Optionally, in step S3, the calculation formula of the alkali removal rate Y of the on-site slag is Y = 1 - R1 = 1 - R / T;

[0011] Wherein, R1 is the alkali metal change rate in the on-site slag, and T is the empirical conversion coefficient;

[0012] R is the alkali metal change rate in the experimental slag, and the calculation formula is R = ((percentage of sodium oxide + potassium oxide in alkali-containing slag) - (percentage of sodium oxide + potassium oxide in final slag)) / (percentage of sodium oxide + potassium oxide in alkali-containing slag) x 100%.

[0013] In step S3, T takes 220 kg / t of slag as the conversion benchmark, and T = alkali metal change rate R in experimental slag 220 / alkali metal change rate R1 in on-site slag 220 , alkali metal change rate R1 in on-site slag 220 = 1 - Y 220 , Y 220 is the average value of the average annual alkali removal rate of two or more blast furnaces.

[0014] In a second aspect, the present application provides a detection mechanism for the desulfurization and alkali discharge capacity of blast furnace slag, which is used in the detection method for the desulfurization and alkali discharge capacity of blast furnace slag, and comprises an upper crucible and a lower crucible, the upper crucible is stacked above the lower crucible, and the upper crucible is rotationally connected with the lower crucible, the bottom of the upper crucible is provided with a dripping hole, and the joint of the upper crucible and the lower crucible is provided with a rotationally openable and closable exhaust port.

[0015] Optionally, the upper crucible is provided with a driving shaft at a middle position of the upper crucible, the driving shaft is used to drive the upper crucible to rotate relative to the lower crucible, the bottom of the lower crucible is provided with two or more clamping parts used to be clamped and fixed with a mounting seat, and the mounting seat is used to mount the detection mechanism in a detection device.

[0016] Optionally, the exhaust port is arranged at the upper end of the lower crucible, and the bottom edge of the upper crucible downwardly extends to form a plurality of spaced apart shielding parts, and the shielding parts are used to close the exhaust port.

[0017] In a third aspect, the present application provides a detection device for the desulfurization and alkali discharge capacity of blast furnace slag, which comprises a vertical tube furnace, a mounting seat and the detection mechanism, and the detection mechanism is placed in a constant temperature zone of the vertical tube furnace through the mounting seat.

[0018] Optionally, the upper and lower ends of the corundum tube of the vertical tube furnace are sealed through flange assemblies, the mounting seat is arranged to extend into the corundum tube through an opening at the bottom of the flange assembly at the lower end, and is fixedly connected with the flange assembly at the lower end through an end sealing sleeve.

[0019] Optionally, the bottom of the mounting seat forms a flange edge, the flange edge is provided with two or more positioning protrusions, and the bottom of the flange assembly at the lower end is provided with positioning grooves matched with the positioning protrusions.

[0020] Optionally, the driving shaft of the upper crucible extends out of the flange assembly at the upper end of the corundum tube, and is coaxially and fixedly connected with a rotating shaft of a stepping motor through a shaft coupling, and the stepping motor is driven by a timer.

[0021] In summary, the present application has at least one of the following beneficial effects:

[0022] 1. The application provides a kind of detection method of high furnace slag desulfurization alkali discharge capacity, a kind of method for determining the high furnace slag desulfurization alkali discharge capacity of slag-gold reaction in high furnace during field blast furnace ironmaking is proposed, to determine the influence of slag property on desulfurization alkali discharge by the sulfur content of molten iron after reaction and the sodium oxide, potassium oxide content of final slag.The present application is scientific in theory, simple in method, and good in reproducibility, which can provide basic data for the actual production of blast furnace and quantitative improvement measures and slag system optimization scheme for actual production according to the experimental results, to ensure that the S content in molten iron of blast furnace remains stable and the smooth operation of blast furnace.The calculation formula of field slag alkali discharge rate provided by the application can simply, intuitively and truly simulate the alkali discharge effect of field slag.

[0023] 2. The application provides a kind of detection mechanism of high furnace slag desulfurization alkali discharge capacity, detection mechanism includes upper crucible and lower crucible, upper crucible is stacked on the upper of lower crucible, and upper crucible is rotatably connected with lower crucible, the bottom of upper crucible is provided with drop hole, and the connecting portion of upper crucible and lower crucible is provided with rotatable opening and closing exhaust port, the double-layer crucible with specific structure is used, the atmosphere of slag-gold reaction process is adjusted by controlling the opening and closing of exhaust port, the process of field blast furnace ironmaking is more intuitively, truly and controllably simulated, and the reaction efficiency of slag-gold is further improved.

[0024] 3. The application provides a kind of detection device of high furnace slag desulfurization alkali discharge capacity, including vertical tube furnace, mounting seat and detection mechanism, which can adapt to conventional vertical tube furnace, and is widely applied and suitable for promotion.The detection device provided by the application drives the upper crucible to rotate by using stepper motor driven by timer programming, improves the convenience of operation, and more truly simulates the reaction process of field blast furnace ironmaking, periodically controls the reaction atmosphere according to the reaction process, and improves the efficiency and reliability of detection. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the sample placement schematic diagram in the slag-gold reaction detection mechanism of the present application embodiment 1-4;

[0026] Figure 2 It is the overall structure schematic diagram of slag-gold reaction detection device of the present application embodiment 1-4;

[0027] Figure 3 It is the overall structure schematic diagram of slag-gold reaction detection device of the present application embodiment 5;

[0028] Figure 4 It is the structure schematic diagram of exhaust port opening of detection mechanism of the present application embodiment 5;

[0029] Figure 5 It is the sectional view of detection mechanism of the present application embodiment 5;

[0030] Figure 6 is a structural schematic view of the detection mechanism of the embodiment 5 of the present application when the exhaust port is closed;

[0031] Mark for explanation: 100, vertical tubular furnace, 1, molybdenum wire, 2, working thermocouple, 3, gas outlet, 4, silicon molybdenum rod, 5, corundum tube, 6, gas inlet, 7, detection mechanism, 71, upper crucible, 711, limiting ring, 712, dripping hole, 713, shielding part, 714, mounting hole, 72, lower crucible, 721, clamping part, 73, driving shaft, 701, exhaust port, 8, flange assembly, 9, mounting seat, 901 flange edge, 10, end sealing sleeve. DETAILED DESCRIPTION

[0032] The present application provides a kind of detection method and detection mechanism and detection device of high furnace slag desulfurization alkali discharge capacity, to make the purpose, technical scheme and effect of the present application more clear, definite, the following is further detailed to the present application.It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] Due to the characteristics of low melting point and small density, the molten slag can be suspended above the molten iron during the blast furnace ironmaking process, making it easy to separate slag and gold. During the blast furnace ironmaking process, the slag acts as the main carrier for desulfurization in the blast furnace, effectively inhibiting the entry of sulfur into the molten iron. In addition, after the alkali metal compounds enter the slag, they are separated from the molten iron after the reaction is complete, allowing the alkali metal compounds to be discharged with the slag, thereby inhibiting the harmful effects of alkali metals on the furnace. Therefore, the desulfurization and alkali discharge capacity of the blast furnace slag directly affects the quality of the product, and thus becomes a research focus in the metallurgical field. Currently, researchers typically use gas-slag equilibrium and gas-slag-gold equilibrium methods to study the desulfurization and alkali discharge capacity of the blast furnace slag. However, these methods measure the conditions under ideal state, reaching thermodynamic and kinetic equilibrium, and require stable oxygen and sulfur partial pressures, strict sealing and operability of the high-temperature furnace, increasing the difficulty and cost of the research.

[0034] The present application provides a kind of detection method and detection mechanism and detection device of high furnace slag desulfurization alkali discharge capacity, to make the purpose, technical scheme and effect of the present application more clear, definite, the following is further detailed to the present application.It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0035] The present application provides a kind of detection method of high furnace slag desulfurization alkali discharge capacity, specifically comprising the following steps:

[0036] S1. Preparing sulfur-containing iron: taking on-site pig iron and FeS reagent as raw materials for preparing sulfur-containing iron, weighing the raw materials according to the sulfur content of the sulfur-containing iron, and then melting and casting the raw materials to obtain the sulfur-containing iron. The C content of the on-site pig iron is 3.5-5% by mass, the FeS reagent is a chemical pure reagent, and the sulfur content of the sulfur-containing iron is 0.1-1%.

[0037] S2. Preparing alkali-containing slag: weighing the raw material reagents to prepare the alkali-containing slag according to the composition of the on-site blast furnace slag, heating the raw material reagents to melt them, and then cooling to obtain the alkali-containing slag and detecting the alkali metal content in the alkali-containing slag. The raw material reagents of the blast furnace slag are prepared according to the composition of the on-site blast furnace slag, and the raw material reagents used in the present application include CaCO3, SiO2, Al2O3, MgO, Na2CO3, and K2CO3. The composition of the raw material reagents is as follows: SiO2 20-35%, Al2O3 8-16%, MgO 3-10%, Na2CO3 0.5-3%, K2CO3 0.5-3%, and the balance being CaCO3, by mass. The raw material reagents are all chemical pure reagents.

[0038] S3. Performing slag-metal reaction: placing the prepared sulfur-containing iron and alkali-containing slag in the detection mechanism of the detection device, performing temperature rising reaction, cooling after the reaction, separating the slag and metal, and obtaining the final slag and iron. The formation process of the blast furnace slag mainly includes initial slag, intermediate slag, and final slag. After the iron-making raw materials enter the blast furnace, the falling process is heated to increase the temperature, and the softening zone is formed in the blast furnace, and then the initial slag is formed. In the softening zone and the hearth area of the blast furnace, the initial slag falling downward passes through the coke layer and meets the upward gas flow, and then performs the solid-liquid-gas multiphase reaction with the gas flow and coke to form the intermediate slag. The intermediate slag gathers after descending to the hearth area, and finally forms the final slag after passing through the slag layer. In order to ensure that the molten iron and slag are in full contact, and to simulate the dynamic process of the iron flowing from top to bottom through the slag, the sulfur-containing iron is placed above and the alkali-containing slag is placed below. The temperature of the temperature rising reaction in step S3 is 1400-1600℃.

[0039] Detecting the alkali metal content in the final slag and the sulfur content in the iron. The sulfur content in the iron is determined by a carbon-sulfur analyzer. Since the alkali metal content in the alkali-containing slag and the final slag is low, and the alkali metal elements are difficult to accurately determine, an inductively coupled plasma optical emission spectrometer (ICP-OES) is used to determine the alkali metal content in the alkali-containing slag and the final slag.

[0040] The alkali metal content in the alkali-containing slag and final slag is determined, and the change rate R of the alkali metal (sodium oxide + potassium oxide) in the experimental slag before and after the slag-gold reaction is calculated, the calculation formula is: R = ((the percentage of sodium oxide + potassium oxide in the alkali-containing slag) - (the percentage of sodium oxide + potassium oxide in the final slag)) / (the percentage of sodium oxide + potassium oxide in the alkali-containing slag) * 100%, and then the change rate R1 of the alkali metal in the field slag can be calculated according to the empirical conversion coefficient T, that is, R1 = R / T, so that the field alkali discharge rate Y = 1-R1 = 1-R / T of the actual production can be obtained. The empirical conversion coefficient T is taken as the benchmark when the amount of slag is 220 kg / t, and the change rate R of the alkali metal in the experimental slag is calculated 220 / the change rate R1 of the alkali metal in the field slag 220 , the change rate R1 of the alkali metal in the field slag 220 = 1-Y 220 , Y 220 is the average value of the average annual alkali discharge rate of two or more blast furnaces.

[0041] In order to further more intuitively, truly and controllably simulate the slag-gold reaction process in the field blast furnace, the application provides a detection mechanism for the desulfurization and alkali discharge capacity of blast furnace slag, which is used for the detection method for the desulfurization and alkali discharge capacity of blast furnace slag. The detection mechanism comprises an upper crucible and a lower crucible, the upper crucible is stacked above the lower crucible, and the upper crucible is rotatably connected with the lower crucible, the bottom of the upper crucible is provided with a dripping hole, and the connection part of the upper crucible and the lower crucible is provided with a rotatable opening and closing exhaust port. The upper crucible and the lower crucible are both made of graphite material, so that the slag-gold reaction is carried out in a carbon potential atmosphere, the upper crucible is used for placing sulfur-containing iron, and the lower crucible is used for placing alkali-containing slag. The sulfur-containing iron in the upper crucible is melted and dripped into the alkali-containing slag in the lower crucible through the dripping hole, simulating the process of forming final slag from initial slag by the downward dripping reaction of furnace charge in the blast furnace. The applicant found during research that as the reaction proceeds, the gas phase increases, and the gas pressure in the lower crucible increases, which hinders the dripping of molten iron in the upper crucible. The applicant uses a detection mechanism with a specific structure, uses a rotatable opening and closing exhaust port, and opens the exhaust port when needed to promote the exhaust of the lower crucible, release the gas pressure of the lower crucible, facilitate the dripping of molten iron in the upper crucible, promote the slag-gold reaction, and more truly and efficiently simulate the ironmaking process in the blast furnace in the actual production process.

[0042] Specifically, a driving shaft for driving the upper crucible to rotate relative to the lower crucible is arranged at the middle position of the upper crucible, and the bottom of the lower crucible is provided with two or more clamping parts for clamping and fixing with the mounting seat, and the mounting seat is used to install the detection mechanism in the detection device. The exhaust port is arranged at the upper end of the lower crucible, and the bottom edge of the upper crucible extends downward to form a plurality of spaced apart shielding parts, which are used to close the exhaust port.

[0043] Further, the application provides a detection device for the desulfurization and alkali discharge capacity of blast furnace slag, which comprises a vertical tube furnace, a mounting seat and the detection mechanism. The detection mechanism is placed in the corundum tube in the constant temperature zone of the vertical tube furnace through the mounting seat. The upper and lower ends of the corundum tube are sealed by flange assemblies. The mounting seat is inserted into the corundum tube through the opening at the bottom of the flange assembly at the lower end and is fixedly connected with the flange assembly through an end sleeve. The bottom of the mounting seat is provided with a flange edge, and the flange edge is provided with two or more positioning protrusions. The bottom of the flange assembly at the lower end is provided with positioning grooves matched with the positioning protrusions, so as to further improve the stability of the mounting seat. The driving shaft is extended from the flange assembly at the upper end of the corundum tube. By rotating the driving shaft, the upper crucible is driven to rotate relative to the lower crucible, so as to control the opening or closing of the exhaust port of the lower crucible by the shielding part of the upper crucible, so as to realize the controllable atmosphere in the slag-gold reaction process.

[0044] In order to more conveniently and truly simulate the on-site blast furnace reaction of slag, the end of the flange assembly at the extended upper end of the driving shaft is coaxially fixedly connected with the rotating shaft of the stepping motor through a shaft coupling. The stepping motor is driven by a timer program. The exhaust port of the application is uniformly and evenly arranged along the circumference of the lower crucible, and the exhaust port is arranged in three. The stepping motor is arranged to rotate 60° at intervals of 5 min. Before the temperature rising reaction, the exhaust port is closed by the shielding part. After heating for 5 min, the stepping motor rotates 60°, drives the shielding part away from the exhaust port, so that the exhaust port is opened, the reaction gas is released, and after heat preservation for 5 min, the stepping motor continues to rotate 60°, so that the exhaust port is closed by the shielding part again. After continuing heat preservation for 5 min, the stepping motor continues to rotate 60°, and the exhaust port is opened again. The heating reaction is stopped. The application controls the intermittent opening or closing of the exhaust port through the stepping motor, more truly simulates and restores the solid-liquid-gas phase reaction process of on-site blast furnace ironmaking.

[0045] The application will be further described below through specific examples.

[0046] Example 1

[0047] The example provides a detection method for the desulfurization and alkali discharge capacity of blast furnace slag, which specifically comprises the following steps:

[0048] S1. Preparation of Sulfur-Containing Iron: Using on-site pig iron (Jingtang pig iron, containing 4wt% C) and FeS reagent as raw materials for preparing sulfur-containing iron, the raw materials were weighed and prepared according to the set sulfur content of 0.4wt% for sulfur-containing iron. The raw materials were placed in a magnesium-aluminum spinel crucible and then placed in a vacuum induction furnace. The vacuum induction furnace was purged three times with high-purity argon gas. Before each purging, the furnace body was evacuated to 10-20 Pa. After purging, argon gas was continued to be introduced, and the furnace body was heated to the melting temperature of 1500℃ and held for 60 minutes for melting. Then, the mixture was cast to obtain sulfur-containing iron ingots. The top and bottom of the ingots, as well as the oxide scale on the surface, were removed, and the ingots were cut into sulfur-containing iron blocks for later use. The sulfur content of the final prepared sulfur-containing iron blocks was measured to be 0.4wt% by a carbon-sulfur analyzer.

[0049] S2. Preparation of Alkali-Containing Slag: Based on the composition of the blast furnace slag on site, chemically pure reagents Al2O3, CaCO3, SiO2, MgO, Na2CO3, and K2CO3 powders were weighed and mixed according to the following mass ratios: 11.46%, 54.85%, 25.22%, 6.1%, 1.28%, and 1.09%, respectively. The mixture was then ground in agate for 30 minutes, pressed into tablets, and placed in a graphite crucible. The graphite crucible was then suspended in the isothermal zone of a vertical tube furnace using molybdenum wire. After sealing the vertical tube furnace, argon gas was first purged for 30 minutes, followed by heating. The temperature was raised to 1500℃ and held for 60 minutes. The graphite crucible containing the sample was then dropped into cold water for quenching, removed, and dried to obtain the initial alkali-containing slag. This was then ground, pulverized, and pressed into tablets again to obtain the final alkali-containing slag. The prepared alkali-containing slag was dried, ground, and digested. The contents of alkali metal oxides in the alkali-containing slag were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) to be 1.14 wt% Na2O and 1.19 wt% K2O.

[0050] S3. Perform the slag-gold reaction: Refer to... Figure 1 As shown, the prepared alkali-containing slag and sulfur-containing iron are placed in the detection mechanism 7. In this embodiment, the detection mechanism 7 is a graphite crucible. Under the condition of 200 kg / t slag, 50 g of the sulfur-containing iron block with a sulfur content of 0.4 wt% prepared in step S1 is taken, and 10 g of the alkali-containing slag after being processed and pressed in step S2 is taken as a sample. The samples are placed in the detection mechanism 7 with the sulfur-containing iron on top and the alkali-containing slag on the bottom, as shown in the figure. Figure 2A suspension wire is fixed to the upper end of the detection mechanism 7. The lower end of the molybdenum wire 1 is bent. The detection mechanism 7 hooks the suspension wire and slowly lifts the detection mechanism 7 containing the sample from bottom to top into the corundum tube 5 in the constant temperature zone of the vertical tube furnace 100 using the molybdenum wire 1. It is then placed stably. A protective sleeve is fitted over the molybdenum wire 1. Both the upper and lower ends of the corundum tube 5 are sealed by the flange assembly 8. After the corundum tube 5 is sealed, argon gas is first introduced through the air inlet 6 for 30 minutes for gas washing. The air inlet 6 is located on the flange assembly 8 at the lower end, and the corresponding air outlet 3 is located on the flange assembly 8 at the upper end. The vertical tube furnace uses a silicon molybdenum rod 4 to achieve heating and temperature rise. A working thermocouple 2 is inserted near the position of the detection mechanism 7 to accurately measure the working temperature. After the gas washing is completed, the temperature is raised to 1500℃ and held for 15 minutes. Heating is then stopped, and the molybdenum wire 1 is quickly stretched so that the detection mechanism 7 carrying the sample can be quickly lowered to the bottom of the vertical tube furnace 100 for cooling. After it cools to room temperature, the argon gas is turned off, the sample is taken out, the slag and gold are separated, and the final slag and iron are obtained. The alkali metal content in the final slag and the sulfur content in the iron are then detected.

[0051] The final residue was pulverized and ground, then digested and analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). The composition of alkali metal oxides in the final residue was determined to be Na₂O - 0.44 wt% and K₂O - 0.27 wt%. The sulfur content in the iron was determined using a carbon-sulfur analyzer, and the S content was found to be 0.041 wt%. R was calculated. 200 = ((Percentage of sodium oxide + potassium oxide in alkaline slag) - (Percentage of sodium oxide + potassium oxide in final slag)) / (Percentage of sodium oxide + potassium oxide in alkaline slag) × 100% = 69.53%.

[0052] Because experimental conditions differ from the actual production conditions and scale of the blast furnace on-site, it is necessary to transform the experimental data by comparing it with actual on-site production data to better reflect real-world production. Taking Shougang Jingtang as an example, the sulfur content in the produced iron is <0.05wt%, and using 220kg / t slag as a baseline, Y... 220 Y is the average annual alkali discharge rate of the three blast furnaces on site. 220 The change rate R1 of alkali metals in the slag at the site was 83.5%. 220 =1-Y 220 =16.5%, and the experiment was conducted under the experimental conditions of Example 1 with a slag quantity of 220 kg / t. R was calculated. 220 = ((Percentage of sodium oxide + potassium oxide in alkali residue) - (Percentage of sodium oxide + potassium oxide in final residue)) / (Percentage of sodium oxide + potassium oxide in alkali residue) × 100%, to obtain R. 220 The value is 61.57%. Calculate the empirical conversion factor T, T = R. 220 / R1 220= 61.57% / 16.5% = 3.73.

[0053] In Example 1, under the condition of 200 kg / t slag amount, R 200 = 69.53%, according to the conversion formula, the change rate R1 of alkali metals in the slag on site is calculated 200 = R 200 / T = 69.53% / 3.73 = 18.64%, that is, the on-site alkali discharge rate Y is obtained 200 = 1-R1 200 = 81.36%. Thus, the slag of Example 1 has good desulfurization effect and alkali discharge effect.

[0054] Example 2

[0055] Example 2 differs from Example 1 in that in step S2 of Example 2, according to the actual production blast furnace slag composition, the basicity of the blast furnace slag is adjusted, and the chemical pure reagents Al2O3, CaCO3, SiO2, MgO, Na2CO3, K2CO3 are weighed according to the mass ratio of 11.72%, 51.09%, 28.53%, 6.23%, 1.31%, 1.12%, and the remaining preparation steps are the same as those of Example 1. In step S2, the content of alkali metal oxides in the alkali-containing slag is determined by inductively coupled plasma optical emission spectrometer (ICP-OES) as Na2O-0.8wt%, K2O-1wt%. In step S3, the composition of alkali metal oxides in the final slag after reaction is determined by inductively coupled plasma optical emission spectrometer (ICP-OES) as Na2O-0.67wt%, K2O-0.44wt%, and the sulfur content in the iron is determined by a carbon-sulfur analyzer as 0.05wt%.

[0056] The content change rate R of alkali metals in the slag in Example 2 is calculated as 38.33%, and T is 3.73, so the actual on-site alkali discharge rate Y = 1-R / T = 89.72% is obtained. Compared with Example 1, after adjusting the composition of the slag in Example 2, a higher alkali discharge rate can be achieved, and the slag has a better alkali discharge effect, but the desulfurization effect is not as good as that of Example 1.

[0057] Example 3

[0058] Example 3 is different from Example 1 in that, in step S2 of Example 3, the MgO content of the blast furnace slag is adjusted according to the actual production blast furnace slag composition. According to the mass ratio of 11.39%, 55.84%, 26.03%, 4.38%, 1.27%, 1.09%, the chemical pure reagents Al2O3, CaCO3, SiO2, MgO, Na2CO3, K2CO3 are weighed, and the remaining preparation steps are the same as those of Example 1. In step S2, the content of alkali metal oxides in the alkali-containing slag is determined by inductively coupled plasma emission spectrometer (ICP-OES) to be Na2O-0.97wt%, K2O-1.09wt%. In step S3, the composition of alkali metal oxides in the final slag after reaction is determined by inductively coupled plasma emission spectrometer (ICP-OES) to be Na2O-0.79wt%, K2O-0.24wt%, and the sulfur content in the iron is determined by a carbon-sulfur analyzer to be 0.057wt%.

[0059] The content change rate R of alkali metals in the slag in Example 3 is calculated to be 50.00%, and T is 3.73, so that the actual production site alkali removal rate Y = 1-R / T = 86.60% is obtained. After adjusting the composition of the slag in Example 3 compared with Example 1, a higher alkali removal rate can be achieved, and the slag has a better alkali removal effect. However, the sulfur content in the iron exceeds 0.05wt%, and the desulfurization effect is not good.

[0060] Example 4

[0061] Example 4 is different from Example 1 in that, in step S2 of Example 4, the Al2O3 content of the blast furnace slag is adjusted according to the actual production blast furnace slag composition. According to the mass ratio of 13.34%, 53.34%, 24.77%, 6.15%, 1.29%, 1.11%, the chemical pure reagents Al2O3, CaCO3, SiO2, MgO, Na2CO3, K2CO3 are weighed, and the remaining preparation steps are the same as those of Example 1. In step S2, the content of alkali metal oxides in the alkali-containing slag is determined by inductively coupled plasma emission spectrometer (ICP-OES) to be Na2O-0.72wt%, K2O-0.78wt%. In step S3, the composition of alkali metal oxides in the final slag after reaction is determined by inductively coupled plasma emission spectrometer (ICP-OES) to be Na2O-0.32wt%, K2O-0.16wt%, and the sulfur content in the iron is determined by a carbon-sulfur analyzer to be 0.05wt%.

[0062] The content change rate R of alkali metals in the slag in Example 4 is calculated to be 68.00%, and T is 3.73, so that the actual production site alkali removal rate Y = (1-R / T)╳100% = 81.77% is obtained. After adjusting the composition of the slag in Example 4 compared with Example 1, a similar desulfurization and alkali removal effect is achieved, but the desulfurization effect is not as good as that of Example 1.

[0063] Example 5

[0064] Example 5 differs from Example 1 in step S3, referring to Figure 3 , the detection device used in the slag-gold reaction of Example 5 includes a vertical tube furnace 100, a mounting seat 9, and a detection mechanism 7, which is placed in the corundum tube 5 of the constant temperature zone of the vertical tube furnace 100 through the mounting seat 9. Specifically, the mounting seat 9 of the present embodiment uses a graphite tube, the bottom of the flange assembly 8 at the lower end is opened, the bottom of the mounting seat 9 is outwardly folded to form a flange edge 901, the mounting seat 9 is inserted into the corundum tube 5 from the bottom opening of the flange assembly 8, the bottom outer wall of the flange assembly 8 is threadedly connected to an end sealing sleeve 10, and the flange edge 901 is abutted and fixed to the bottom of the flange assembly 8 at the lower end by using the end sealing sleeve 10. Preferably, in order to improve the stability of the mounting seat 9, the flange edge 901 can be positioned and connected with the bottom of the flange assembly 8 by integrally forming two or more positioning protrusions, and the corresponding flange assembly 8 is provided with positioning grooves matched with the positioning protrusions.

[0065] Referring to Figure 4 , the detection mechanism 7 of the present embodiment includes an upper crucible 71 and a lower crucible 72, both of which are graphite crucibles. The upper crucible 71 is stacked above the lower crucible 72, and the upper crucible 71 and the lower crucible 72 are rotationally connected. A gas outlet 701 that can be opened and closed is arranged at the connection between the upper crucible 71 and the lower crucible 72.

[0066] Specifically, referring to Figure 5 , a limiting ring 711 is provided at the bottom of the upper crucible 71 near the edge, and the top of the lower crucible 72 is inserted into the limiting ring 711, so that the upper crucible 71 and the lower crucible 72 are rotationally connected. The bottom of the lower crucible 72 forms two or more clamping portions 721, and the mounting seat 9 correspondingly forms clamping grooves to achieve clamping and fixing of the lower crucible 72 and the mounting seat 9. The bottom of the upper crucible 71 is provided with a dripping hole 712, the upper crucible 71 contains sulfur-containing iron, and the lower crucible 72 contains alkali-containing slag. After the sulfur-containing iron is heated and melted, it can drip into the alkali-containing slag through the dripping hole 712 for slag-gold reaction. One or more gas outlets 701 are provided near the top of the lower crucible 72, and the number of gas outlets 701 in the present embodiment is three. The gas outlets 701 are located at the same height of the lower crucible 72 and have the same geometric size, and are uniformly and evenly distributed along the circumference of the lower crucible 72. Correspondingly, the bottom of the upper crucible 71 outside the limiting ring 711 extends downward to form three uniformly and evenly distributed shielding portions 713, the positions and geometric sizes of which are matched with the gas outlets 701. By rotating the upper crucible 71, the shielding portions 713 shield the gas outlets 701, thereby closing the gas outlets 701.Figure 6 as shown.

[0067] Referring to Figure 4 , Figure 5 The detection mechanism 7 includes a drive shaft 73 for driving the upper crucible 71 to rotate, the drive shaft 73 is made of a graphite rod, the lower end of the graphite rod is integrally formed into a polygonal body, which is a hexagonal body in this embodiment, a mounting hole 714 matching the size of the polygonal body is formed at the central position of the corresponding upper crucible 71, the lower end of the drive shaft 73 is inserted into the mounting hole 714 of the upper crucible 71, and the drive shaft 73 is clamped and fixed with the upper crucible 71. The upper end of the drive shaft 73 is coaxially fixedly connected with the rotating shaft of a stepping motor (not shown in the figure) through a shaft coupling, the stepping motor is programmed by a timer to drive the stepping motor to rotate, and in this embodiment, the stepping motor is set to rotate 60° every 5 minutes, thereby driving the drive shaft to rotate 60° every 5 minutes, so that the shielding part 713 of the upper crucible 71 rotates to shield the exhaust port 701 every 5 minutes, while maintaining the reaction atmosphere of the lower crucible 72, the gas product is intermittently discharged, the gas pressure of the lower crucible 72 is released, and the molten iron in the upper crucible 71 is promoted to drop into the lower crucible 72 to continue the reaction.

[0068] The implementation process of step S3 of the slag-gold reaction in this embodiment is as follows:

[0069] 1. Place the alkali-containing slag in the lower crucible 72 of the detection mechanism 7, and place the sulfur-containing iron in the upper crucible 71, then stack the upper crucible 71 on the lower crucible 72, so that the top of the lower crucible 72 is installed in the limiting ring 711 of the upper crucible 71, to realize the rotary connection of the upper crucible 71 and the lower crucible 72, rotate the drive shaft 73 to drive the upper crucible 71 to rotate to the shielding part 713 corresponding to the exhaust port 701 of the lower crucible 72;

[0070] 2. Install the detection mechanism 7 with the sample in the mounting seat 9, and clamp the clamping part 721 of the lower crucible 72 in the clamping groove of the mounting seat 9, to realize the clamping and fixing of the lower crucible 72 and the mounting seat 9;

[0071] 3. Slowly insert the mounting seat 9 with the detection mechanism 7 into the constant temperature zone of the upright tube furnace 100 from the bottom opening of the lower end flange assembly 8, until the flange edge 901 of the mounting seat 9 abuts against the lower end of the flange assembly 8, and install the mounting end sleeve 10, so that the mounting seat 9 is fixed with the flange assembly 8;

[0072] 4. Install the upper end flange assembly 8, and make the drive shaft 73 of the detection mechanism 7 protrude from the top of the upper end flange assembly 8, and the protruding part of the drive shaft 73 from the upper end of the flange assembly 8 is coaxially fixedly connected with the rotating shaft of the stepping motor through a shaft coupling;

[0073] 5. For the sealed flange assembly 8, argon gas is introduced for purging. After purging, the temperature is raised for reaction. After the temperature of the vertical tube furnace reaches 1500℃, it is held for 5 minutes. Then, the stepper motor rotates 60°, driving the drive shaft 73 to rotate the upper crucible 71 until the shielding part 713 is away from the exhaust port 701, so that the exhaust port 701 is opened. The temperature is held for another 10 minutes. When the temperature is held for 5 minutes, the stepper motor continues to rotate 60° to close the exhaust port 701. When the temperature is held for 10 minutes, the heating is stopped, and the stepper motor continues to rotate 60° to open the exhaust port 701. After it cools down to room temperature, the argon gas is turned off, the sample is taken out, and the slag gold is separated to obtain the final slag and iron.

[0074] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for detecting the desulfurization and alkali removal capacity of blast furnace slag, characterized in that, Specifically, the following steps are included: S1. Preparation of sulfur-containing iron: Using on-site pig iron and FeS reagent as raw materials for preparing the sulfur-containing iron, the raw materials are weighed and prepared based on the sulfur content set for the sulfur-containing iron, and the raw materials are melted and cast to obtain the sulfur-containing iron; S2. Preparation of alkali-containing slag: Based on the composition of the blast furnace slag on site, weigh the raw materials and reagents to prepare alkali-containing slag, heat the raw materials and reagents of the alkali-containing slag to melt, cool and obtain the alkali-containing slag, and detect the alkali metal content in the alkali-containing slag; S3. Perform slag-gold reaction: Place the prepared sulfur-containing iron and the alkali-containing slag in the detection mechanism of the detection device, carry out the heating reaction, cool after the reaction is completed, separate the slag and gold, obtain the final slag and iron, and detect the alkali metal content in the final slag and the sulfur content in the iron. The detection mechanism includes an upper crucible and a lower crucible. The upper crucible is stacked on top of the lower crucible and is rotatably connected to the lower crucible. A drip hole is provided at the bottom of the upper crucible, and a rotatable vent is provided at the connection between the upper and lower crucibles. The exhaust port is located at the upper end of the lower crucible, and the bottom edge of the upper crucible extends downward to form a spaced-out shielding part, which is used to close the exhaust port. The upper crucible rotates relative to the lower crucible, thereby controlling the shielding part of the upper crucible to open or close the exhaust port of the lower crucible, so as to achieve controllable atmosphere in the slag-gold reaction process.

2. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 1, characterized in that, Step S3 also includes calculating the alkali discharge rate Y of the on-site slag, and the calculation formula is: Y=1-R1=1-R / T; Where R1 is the change rate of alkali metals in the field slag, T is the empirical conversion coefficient; R is the change rate of alkali metals in the experimental slag, and the calculation formula is: R = ((percentage of sodium oxide + potassium oxide in alkali slag) - (percentage of sodium oxide + potassium oxide in final slag)) / (percentage of sodium oxide + potassium oxide in alkali slag) × 100%.

3. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 2, characterized in that, In step S3, T is based on a slag quantity of 220 kg / t, and T = the rate of change of alkali metals in the experimental slag, R. 220 / Rate of change of alkali metals in on-site slag R1 220 The rate of change of alkali metals in the slag at the site, R1 220 =1-Y 220 Y 220 It is the average annual alkali discharge rate of two or more blast furnaces on site.

4. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 1, characterized in that, The upper crucible is provided with a drive shaft at the middle position to drive the upper crucible to rotate relative to the lower crucible. The bottom of the lower crucible is provided with two or more locking parts for locking and fixing with the mounting base. The mounting base is used to install the detection mechanism in the detection device.

5. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 1, wherein the detection device includes a vertical tubular furnace, a mounting base, and a detection mechanism, wherein the detection mechanism is placed in the constant temperature zone of the vertical tubular furnace via the mounting base.

6. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 5, characterized in that, The upper and lower ends of the corundum tube of the vertical tube furnace are sealed by flange assemblies. The mounting base extends into the corundum tube through the bottom opening of the flange assembly at the lower end and is fixedly connected to the flange assembly at the lower end by an end-sealing sleeve.

7. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 6, characterized in that, The bottom of the mounting base forms a flange edge, the flange edge is provided with two or more positioning protrusions, and the bottom of the flange assembly at the lower end is provided with a positioning groove that matches the positioning protrusions.

8. The method for detecting the desulfurization and alkali removal capacity of blast furnace slag according to claim 6, characterized in that, The drive shaft of the upper crucible extends from the flange assembly at the upper end of the corundum tube and is coaxially and fixedly connected to the rotating shaft of the stepper motor via a coupling. The stepper motor is driven by a timer program.

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