A drainage agent for a calcium-treated steel start-up ladle and methods of making and using the same

Abstract

The application relates to a drainage agent for a calcium-treated steel starting ladle and a preparation method and application thereof, raw materials are as follows: 5-10% of aluminum magnesium spinel, 60-85% of chrome ore sand, 5-10% of pearl sand, 8-20% of Mongolia sand and 3-5% of slide plate grinding surface collection powder. The drainage agent has strong adaptability to calcium-treated steel, reduces the production cost per ton of steel and the consumption cost of the drainage agent, reduces the safety hidden danger caused by the re-melting rate of the calcium-treated steel starting ladle due to non-self-opening and the oxygen burning leakage accident, the self-opening rate of the starting ladle is increased from 80-83% to 97-99.5%, and the comprehensive cost is effectively reduced.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a novel diverting agent for calcium-treated steel ladle during start-up and its preparation and application methods. Background Technology

[0002] Ladle guiding agent is a metallurgical unshaped refractory material that is resistant to high temperatures and molten steel corrosion, and exhibits stable high-temperature performance. Conventional guiding agents are bulk materials composed of several refractory materials of different particle sizes, which are mechanically stirred, dried, and then filled into the bottom seat bricks and the tundish nozzle orifice of the ladle. Added before molten steel is poured into the ladle, it prevents molten steel from entering the seat bricks and the tundish nozzle orifice, and can withstand the high-temperature erosion and chemical corrosion of the molten steel, forming a structure with a slightly sintered layer at the top. When the ladle is opened for casting, the guiding agent falls rapidly as the tundish nozzle opens, guiding the molten steel through the tundish nozzle orifice into the tundish, making it a crucial material for achieving high-speed continuous casting.

[0003] Studies have found that current calcium-treated steel typically uses chromium-silicon flow guides. The sintering mechanism involves the reaction of the chromite sand phase and the quartz phase, with calcium elements in the molten steel participating in the flow guide sintering reaction. Especially during the start-up of the ladle, the long hot turnover time of the ladle, the long refining time of the molten steel, the high temperature of the molten steel, and the strong fluidity of the molten steel exacerbate the degree of sintering of the flow guide, greatly reduce the self-opening rate of the ladle, increase the number of oxygen burns, and cause an increase in the overall frequency of ladle remelting, which may even lead to major steel leakage accidents, posing serious safety hazards. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a novel diverting agent and its preparation method specifically for calcium-treated steel ladles, aiming to solve the problem of low self-opening rate.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A novel diverting agent for calcium-treated steel ladle starting, characterized in that the raw materials, by weight percentage, are: 5-10% aluminum magnesium spinel, 60-85% chromite sand, 5-10% sappan sand, 8-20% Mongolian sand, and 3-5% slide plate grinding surface collecting powder.

[0006] The aluminum-magnesium spinel is fused aluminum-magnesium spinel, comprising two types of granules: 0.2mm≤particle size 1<0.4mm and 0.4mm≤particle size 2<0.8mm, with the weight ratio of different particle sizes being 5-8:3-5 for particle size 1:particle size 2.

[0007] The chromite sand includes two types of granules: 0.21mm≤particle size 3<0.35mm and 0.35mm≤particle size 4<0.6mm. The weight ratio of the different particle sizes is 7-8:2-5 for particle size 3:particle size 4.

[0008] The alumina includes two types of granules: 0.3mm≤particle size 5<0.42mm and 0.42mm≤particle size 6<0.71mm. The weight ratio of different particle sizes is 7-8:3-5 for particle size 5:particle size 6.

[0009] The Mongolian sand includes two types of granules: 0.6mm≤particle size 7<0.8mm and 0.8mm≤particle size 8<1.2mm. The weight ratio of the different particle sizes is 7:8 = 1-3:5-8.

[0010] The collected powder from the skateboard grinding surface includes three types of granules: 9 < 0.075 mm, 0.075 mm ≤ 10 < 0.15 mm, and 0.15 mm ≤ 11 < 0.3 mm. The weight ratio of 9:10:11 granules is 2-3:5-7:3-4.

[0011] A method for preparing a novel diverting agent for calcium-treated steel ladle is characterized by pre-adding chromite sand and slide plate mill surface collecting powder to a mixer and mixing them evenly to obtain a premix; then adding aluminum magnesium spinel, sappan sand and Mongolian sand to the mixer and mixing them evenly.

[0012] The method for using a new type of diverting agent in the ladle during the start-up of calcium-treated steel includes the following steps: (1) The drainage agent is loaded into the electric heating oven on the sand-adding platform on site and baked at a temperature of 50-80 degrees Celsius for 4-5 hours. (2) Clean the sliding gate and the casting hole of the seat brick of the ladle and blow them clean; (3) Place the ladle below the sand-adding platform for the diverting agent, move the diverting agent sleeve down to align with the casting hole of the ladle nozzle seat brick, and add the diverting agent into the casting hole of the ladle nozzle seat brick through the funnel guide tube; (4) Cover the top of the diverting agent with a silicon-aluminum refractory cap to prevent the molten steel from dispersing the diverting agent.

[0013] The beneficial effects of this invention are: The novel diverting agent for calcium-treated steel ladle in this invention differs from existing products and has the following technical advantages: (1) The flow guide agent of this invention is designed for the start-up ladle of calcium-treated steel. The temperature of the molten steel is relatively high when the ladle is started up, which places high demands on the performance of the flow guide agent. The self-opening rate of the ladle using traditional chromium-silicon flow guide agents is very low. The flow guide agent of this invention, with the addition of aluminum-magnesium spinel particles, reacts slowly with the liquid calcium in the molten steel, making it less likely to form an erosion sintering layer. Through the combined use of different raw materials and strict control of the particle size of each raw material, the particle size distribution is reasonable, resulting in a product with good high-temperature fluidity, high refractoriness, and strong resistance to molten steel penetration, which greatly improves the self-opening rate of the start-up ladle of calcium-treated steel, and the self-opening effect is good. The self-opening rate of the start-up ladle is increased from the original 80%-83% to 97%-99.5%.

[0014] (2) The guide agent of the present invention uses special raw material slide plate grinding surface collection powder. The collection powder is dust generated during the grinding of the slide plate surface by a dry grinding machine. It is obtained by suction and filtration by an induced draft fan. The slide plate grinding powder contains Al2O3, MgO and C. The guide agent utilizes the Al, Mg and carbon elements in it to lubricate the molten steel and prevent sintering.

[0015] (3) None of the components of the flow guide agent of the present invention contaminate the molten steel and will not introduce impurities during the steel smelting process. The chromite sand in the raw materials has high refractoriness, high density, stable high-temperature performance, and good fluidity; Mongolian sand particles are used, and their rounded particles and rapid sintering characteristics are utilized to form a sintered layer of moderate thickness. After the static pressure of the molten steel reaches the opening of the sliding gate, the pouring can be started quickly, which can improve the self-opening rate of the ladle.

[0016] (4) The flow guide agent of the present invention has strong adaptability to the smelting conditions of calcium-treated steel. It changes the traditional practice of preventing non-self-opening by increasing the amount of flow guide agent added, reduces the production cost per ton of steel and the consumption cost per ton of flow guide agent for this steel type, and reduces the safety hazards caused by accidents such as the ladle not opening on its own and being returned to the furnace, or even oxygen burning and steel leakage in severe cases.

[0017] (5) The calcium-treated steel ladle of the present invention has low cost and good performance. In particular, the application of special materials for collecting powder on the slide plate grinding surface is equivalent to waste utilization, turning waste into treasure, saving energy and reducing consumption, and effectively reducing the overall cost.

[0018] (6) When the diverting agent of the present invention is used, a silicon-aluminum refractory cap is added to the top to prevent the molten steel from dispersing the diverting agent, thereby improving the utilization rate and effect of the diverting agent. Detailed Implementation

[0019] The specific embodiments of the present invention will be further described in detail below with reference to examples.

[0020] Example 1: A novel diverting agent for calcium-treated steel ladle and its preparation method Raw material composition: 10% fused alumina-magnesia spinel particles, 74% chromite sand particles, 5% alumina sand particles, 8% Mongolian sand particles, and 3% skateboard grinding surface collecting powder; The main components of the fused aluminum-magnesium spinel particles are: Al2O3 77%, MgO 21%, SiO2 0.25%, and CaO 0.75%. The particles include two types: 0.2mm≤particle size 1<0.4mm and 0.4mm≤particle size 2<0.8mm. The weight ratio of different particle sizes is 5-8:3-5 for particle size 1:particle size 2.

[0021] The main components of chromite sand particles are: Cr2O3 45%, Fe2O3 28%, Al2O3 15%, SiO2 0.6%, and MgO 9.4%. It includes two types of particles: 0.21mm≤particle size 3<0.35mm and 0.35mm≤particle size 4<0.6mm. The weight ratio of different particle sizes is 7-8:2-5 for particle size 3:particle size 4.

[0022] The main components of granulated sand are: Al2O3 75%, SiO2 15%, TiO2 2%; it includes two types of granules: 0.3mm≤particle size 5<0.42mm and 0.42mm≤particle size 6<0.71mm. The weight ratio of different particle sizes is 7-8:3-5 for particle size 5:particle size 6.

[0023] The main components of Mongolian sand particles are: SiO2 91.6%, Al2O3 2.4%, Fe2O3 0.3%, and C 1.2%. It includes two types of granules: 0.6mm≤particle size 7<0.8mm and 0.8mm≤particle size 8<1.2mm. The weight ratio of different particle sizes is 7:8 = 1-3:5-8.

[0024] The main components of the collecting powder for the skateboard grinding surface are: Al2O3 77.1%, MgO 14.8%, and C 6.2%. It includes three types of granules with particle sizes of 9 < 0.075 mm, 0.075 mm ≤ particle size 10 < 0.15 mm, and 0.15 mm ≤ particle size 11 < 0.3 mm. The weight ratio of particle size 9: particle size 10: particle size 11 is 2-3:5-7:3-4.

[0025] The dust collected from the grinding surface of the sliding plate is the dust generated during the grinding process of the sliding plate by the dry grinding machine. It is drawn in by the induced draft fan, and the larger dust particles are settled at the bottom by the cyclone dust collector. Then, the dust is collected by the filter cartridge of the pulse-jet filter dust collector to obtain the grinding surface dust of the sliding plate.

[0026] Preparation method of the diversion agent: Chromite sand and slide plate mill surface collection powder are pre-added to a mixer and stirred evenly to obtain a premix; then aluminum magnesium spinel, jewel sand and Mongolian sand are added to the mixer and stirred evenly. Example

[0027] A novel diverting agent for calcium-treated steel ladle is provided, comprising: 5% fused aluminum-magnesium spinel particles, 72% chromite sand particles, 5% alumina sand particles, 13% Mongolian sand particles, and 5% slide plate mill surface collecting powder.

[0028] Other raw material requirements and preparation methods are the same as in Example 1. Example

[0029] A special guide sand for starting up a calcium-treated steel ladle, the raw materials are: 8% fused aluminum magnesium spinel particles, 65% chromite sand particles, 8% alumina sand particles, 15% Mongolian sand particles, and 4% slide plate grinding surface collecting powder.

[0030] Other raw material requirements and preparation methods are the same as in Example 1.

[0031] Example 4: The method of using the novel diverting agent for calcium-treated steel ladle during start-up according to the present invention includes the following steps: (1) The drainage agent is loaded into the electric heating oven on the sand-adding platform on site and baked at a temperature of 50-80 degrees Celsius for 4-5 hours. (2) Clean the sliding gate and the casting hole of the seat brick of the ladle and blow them clean; (3) Place the ladle below the sand-adding platform for the diverting agent, move the diverting agent sleeve down to align with the casting hole of the ladle nozzle seat brick, and add the diverting agent into the casting hole of the ladle nozzle seat brick through the funnel guide tube; (4) Cover the top of the diverting agent with a silicon-aluminum refractory cap to prevent the molten steel from dispersing the diverting agent, which is beneficial to improving the self-opening rate.

[0032] The product of Example 1 was applied to the production process of a 150-ton steel ladle and DC01-1R steel grade in a steel plant.

[0033] After the ladle has been used for one heat, the sliding nozzle and the bedding brick casting hole are cleaned by oxygen blowing. The oxygen blowing pipe is aligned with the nozzle casting hole to clean the cold steel and residue inside the sliding nozzle casting hole. After the sliding nozzle casting hole of the ladle is cleaned, it is hoisted onto the ladle car. The ladle is transported to the diverting agent sand adding platform, the sliding nozzle is closed, the diverting agent of this invention is heated, and added to the ladle sliding nozzle and bedding brick casting hole through the diverting agent funnel guide pipe. A silicon-aluminum refractory cap is placed on top of the diverting agent to prevent the molten steel from dispersing the diverting agent.

[0034] After the diverting agent is added, it is ready to receive molten steel. After refining and other processes, the molten steel is loaded onto the continuous casting machine and pulls the hydraulic cylinder of the sliding gate mechanism, so that the molten steel flows out smoothly and the casting process is automatically started.

[0035] Other embodiments of the product of this invention can also be applied to production processes of ladles of different tonnages and different steel grades, achieving the same self-starting rate for the ladle. For example, it can be applied to a process in a steel plant using a 120-ton ladle to produce 40Cr steel, and to a process in a steel plant using a 180-ton ladle to produce 42CrMoA steel.

[0036] Application statistics over the past year show that the self-opening rate of calcium-treated steel ladles has increased from 80%-83% to 97%-99.5%, indicating good performance.

Claims

1. A flow-guiding agent for starting up a calcium-treated steel ladle, characterized in that, The raw materials, by weight percentage, are: 5-10% aluminum-magnesium spinel, 60-85% chromite sand, 5-10% cerium silicate sand, 8-20% Mongolian sand, and 3-5% skateboard grinding surface collecting powder; The aluminum-magnesium spinel is fused aluminum-magnesium spinel, comprising two types of granules: 0.2mm≤particle size 1<0.4mm and 0.4mm≤particle size 2<0.8mm, with the weight ratio of different particle sizes being 5-8:3-5 for particle size 1:particle size 2. The chromite sand includes two types of granules: 0.21mm≤particle size 3<0.35mm and 0.35mm≤particle size 4<0.6mm. The weight ratio of the different particle sizes is 7-8:2-5 for particle size 3:particle size 4. The abrasive sand includes two types of granules: 0.3mm≤particle size 5<0.42mm and 0.42mm≤particle size 6<0.71mm. The weight ratio of different particle sizes is 7-8:3-5 for particle size 5:particle size 6. The main components of the Mongolian sand particles are: SiO2 91.6%, Al2O3 2.4%, Fe2O3 0.3%, and C 1.2%; including two types of particles with particle size 0.6mm≤particle size 7<0.8mm and 0.8mm≤particle size 8<1.2mm, with a weight ratio of particle size 7:particle size 8 = 1-3:5-8; The main components of the collected powder from the skateboard grinding surface are: Al2O3 77.1%, MgO 4.8%, and C 6.2%; it includes three types of granules with particle sizes of 9 < 0.075 mm, 0.075 mm ≤ particle size 10 < 0.15 mm, and 0.15 mm ≤ particle size 11 < 0.3 mm, with a weight ratio of particle size 9: particle size 10: particle size 11 of 2-3:5-7:3-4.

2. A method for preparing the flow-guiding agent for the ladle of calcium-treated steel mill as described in claim 1, characterized in that, Chromite sand and skateboard mill surface collection powder are pre-mixed in a mixer to obtain a premix; then aluminum magnesium spinel, gemstone sand and Mongolian sand are added to the mixer and mixed evenly.

3. A method of using the calcium-treated steel ladle start-up agent as described in claim 1, characterized in that, Includes the following steps: (1) The drainage agent is loaded into the electric heating oven on the sand-adding platform on site and baked at a temperature of 50-80 degrees Celsius for 4-5 hours. (2) Clean the sliding gate and the casting hole of the seat brick of the ladle and blow them clean; (3) Place the ladle below the sand-adding platform for the diverting agent, move the diverting agent sleeve down to align with the casting hole of the ladle nozzle seat brick, and add the diverting agent into the casting hole of the ladle nozzle seat brick through the funnel guide tube; (4) Cover the top of the diverting agent with a silicon-aluminum refractory cap to prevent the molten steel from dispersing the diverting agent.