Silicon-calcium fettling material and use method thereof

Abstract

The invention discloses a technical scheme of a silicon-calcium fettling material and a use method thereof, the fettling material produced by adopting a mixture of a powdery CaO material and a SiO2 material as an aggregate or directly adopting 2CaO. SiO2 and 3CaO. SiO2 clinker as the aggregate can completely meet the requirements of a converter, an electric furnace, an RH refining furnace and a steel ladle lining spraying and repairing process on a spraying and repairing material; the springback material and the eroded repairing material during gunning work enter molten steel or slag in a furnace or a steel ladle, the content of (3CaO. SiO2 + 2CaO. SiO2) or CaO in the slag can be increased, the dephosphorization capacity of the slag is improved, the use amount of lime is reduced, the molten steel is purified, the repairing material is reutilized, and the cost performance is high.

Description

Technical Field

[0001] The invention relates to the field of steelmaking, and in particular to a steelmaking refractory lining repair material. Background Art

[0002] Repair material is an amorphous refractory material used to repair the lining of thermal equipment in the spraying construction method. It is composed of refractory aggregates with a certain particle size distribution, binders and additives (including accelerators, plasticizers, sintering aids and mineralizers, etc.). According to the construction method, it is divided into repair material and spraying material.

[0003] The lining of the steelmaking furnace is easily eroded by molten steel and slag during blowing. If it is not repaired in time, the vulnerable parts of the furnace lining and the slag line and ear axis area will be damaged prematurely. Generally, repair materials are used for repair or gunning materials are used to repair the furnace lining.

[0004] The existing gunning materials used in converters, electric arc furnaces and RH refining furnaces are mainly magnesium lining repair materials and gunning materials. In addition to binders, accelerators and additives totaling about 10-15%, the remaining main raw materials are almost all magnesium or magnesium-calcium materials containing MgO, such as magnesia sand, magnesia-calcium sand, Cr20 sand, 91 magnesia sand, magnesia-calcium brick recycled materials, tricalcium magnesia sand, etc., accounting for 70-90%. For example, the patent application "A magnesia-chrome gunning material for converter and its preparation method (CN201810201605.5)" mainly uses Cr20 sand and 91 magnesia sand containing MgO as the main raw materials; the patent application "A method for producing environmentally friendly quick-drying converter gunning material using waste magnesia-calcium bricks (CN201811191404.8)" mainly uses waste magnesia-calcium bricks as the main raw materials; the patent application "A vanadium-extracting converter gunning material and its preparation method (CN201711260987.0)" mainly uses magnesia olive sand particles and sintered magnesium powder; the patent application "A converter lining gunning material with strong adhesion (CN20221088790 2.6)", mainly using high-purity sintered magnesia particles and fused magnesia particles; the patent application "A low-rebound magnesium-calcium hot gunning material and its preparation method (CN202310356158.1)", the main raw materials are magnesium-calcium sand and fused magnesia; the patent application "A converter repair charge and its preparation method" (CN201910699060.X), also uses fused magnesia, the patent "Process method for making magnesium repair charge for electric arc furnace lining" (CN201310752668.7), the patent "A kind of electric furnace gunning material" (CN92101715.4), is made of fused magnesia as aggregate. In order to reduce costs and MgO raw materials, some limestone is used in the aggregate of the patented "Magnesium-calcium refractory gunning material" (CN201611127135.X). The above series of patented technical solutions propose corresponding different batching schemes for different problems existing in furnace repair, but the main raw materials and components of the furnace repair materials are inseparable from MgO.

[0005] The amount of gunning material is adjusted according to the size of the repair area. Generally, the amount of material used for one repair can reach 800-1500kg, which means that tons of MgO are added to the furnace at one time. The gunning material entering the furnace will eventually enter the slag. The MgO in the slag has no dephosphorization effect except for slowing down the erosion of the lining by the slag and facilitating the slag splashing and furnace protection operation. It not only increases the slag volume, heat loss and iron loss, but also makes it more difficult to use the steel slag.

[0006] The use of magnesium materials for slag making and furnace repairing is based on the use of magnesium linings in converters or electric arc furnaces. Since the implementation of slag splashing furnace protection operations, due to the formation of a slag splashing layer on the surface of the furnace lining, the slag splashing layer blocks the contact between the molten steel slag and the magnesium carbon bricks. The composition of the slag splashing layer is consistent with the slag, so that the MgO in the slag almost loses the effect of slowing down the erosion of the lining by the slag. Summary of the invention

[0007] Aiming at the current situation that all steelmaking furnace linings use MgO as the main raw material for the gunning and repairing materials, the present invention proposes a repairing and gunning material using a mixture of CaO and SiO2 as the aggregate.

[0008] The technical solution of a silicon-calcium furnace filler of the present invention is composed of aggregate and admixture (0-2% of binder, 0-2% of accelerator, 0-5% of sintering aid and mineralizer, 0-3% of plasticizer, 0-1% of dispersant, 0-0.03% of explosion-proof agent), and is characterized in that the aggregate is composed of 60-100% of calcium raw material and 0-50% of silicon raw material.

[0009] According to the requirements of the construction method, adjust the type and amount of admixtures in the repair charge to meet the process requirements of flame gunning, dry gunning or semi-dry gunning and repair materials.

[0010] Furthermore, the ratio of CaO to SiO2 in the silicon-calcium filler material is 2:1 or 3:1 or the ratio of CaO to SiO2 is around 2:1 or 3:1.

[0011] Furthermore, the calcium raw material is one or both of limestone and quicklime.

[0012] Furthermore, the siliceous raw material is one of quartz sand, silica, and quartz mineral.

[0013] Furthermore, the aggregates of the calcium raw materials and the silicon raw materials can be replaced by 2CaO.SiO2 clinker or 3CaO.SiO2 clinker or calcium silicate clinker mainly composed of 3CaO.SiO2 and 2CaO.SiO2.

[0014] Further, the admixture is one or more of sodium dodecyl sulfate, sodium tripolyphosphate, sodium hexametaphosphate, silicon powder, water glass, phenolic resin, silicate cement clinker, calcium aluminate cement, talcum powder, B2O3, silicon carbide, spherical asphalt, kerosene, diesel, engine oil, anthracene oil and LiCO3, talcum powder, B2O3, silicon carbide, water glass, silicon powder, carboxymethyl cellulose, hemp fiber, hydrated lime powder, a-Al2O3 powder, complex magnesium aluminum sol, silica fume, lithium bentonite, paper fiber. Sodium tripolyphosphate, sodium hexametaphosphate, silicon powder, water glass, phenolic resin, calcium aluminate cement, phenolic resin, talcum powder, B2O3, silicon carbide, spherical asphalt and LiCO3.

[0015] Furthermore, according to construction needs, the corresponding repair materials for converters, electric furnaces, RH refining furnaces, flame gunning materials, dry gunning materials, wet gunning materials and ladle repair materials are obtained by adjusting the admixtures.

[0016] Furthermore, the method for using the silicon-calcium repair furnace material is characterized in that after the converter or electric furnace spraying operation, slag splashing and furnace protection operation are carried out after sintering for 10-20 minutes; after the converter or electric furnace repair operation, the molten slag is covered on the repair area and sintered for 10-20 minutes.

[0017] The mechanism of the technical solution of the present invention is that, at present, there are two main types of steelmaking furnace gunning materials and repair materials according to the classification of binders: one is hot gunning materials with asphalt and resin as binders, and the other is water-based materials with phosphate or inorganic substances as binders. The aggregates are all based on MgO materials as the main raw materials. This is based on the magnesium lining used in steelmaking furnaces decades ago, that is, the magnesium carbon bricks of the converter refractory lining are composed of MgO and carbon. In order to slow down the erosion of the lining by slag, MgO-containing slag materials such as dolomite should be added during slag making; the gunning materials are also mainly composed of MgO and carbon. However, since the implementation of the slag splashing furnace protection operation, the formation of the slag splashing layer and the mechanism of slag erosion of the lining have changed. The high-temperature erosion in the late stage of converter blowing is the main cause of lining erosion, so measures to improve the resistance of the lining to high-temperature erosion can meet the requirements.

[0018] The main process of the furnace repair of both converter and electric arc furnace is to apply the repair charge to the severely corroded part to block the slag and magnesia carbon bricks. When the repair charge has a high enough melting point, it can resist the slag corrosion. It is not necessary to use the repair charge with MgO as the main material. The melting point of quartz sand is 1750℃ and the melting point of lime is 2500℃. Although the melting point of quartz sand is low, it may soften at the steelmaking temperature, which is not conducive to being used as a repair material for steelmaking furnaces.

[0019] However, after in-depth research, the applicant found that the mixture of quartz sand and lime in the aggregate is proportioned according to CaO\SiO2 as 2 or 3, and under the conditions of implementing slag splashing furnace protection operations, a dicalcium silicate phase 2CaO.SiO2 with a melting point of 2130°C or a tricalcium silicate phase 3CaO.SiO2 with a melting point of 2070°C can be formed at the steelmaking temperature, and the high-temperature corrosion resistance of the furnace charge is subsequently improved.

[0020] In particular, adding a small amount of Portland cement clinker or steel slag to the mixture of lime and quartz sand, where (3CaO.SiO2+2CaO.SiO2) ≥ 70%, can act as the crystal nucleus of 3CaO.SiO2 and 2CaO.SiO2, and can accelerate the formation of 2CaO.SiO2 or 3CaO.SiO2 under lower temperature conditions. It is a good mineralizer. Among them, tricalcium aluminate (3CaO·Al2O3) and tetracalcium aluminoferrite (iron phase solid solution) (4CaO·Al2O3·Fe2O3) or CaO.FeO, 2CaO.FeO can be used as fluxing phases in supplementary furnace charges without external addition. The dicalcium silicate phase, tricalcium silicate phase, tricalcium aluminate and tetracalcium aluminoferrite have relatively high gelling strength and adhesion. The water-based gunning material with silicate clinker as the main material does not need to be added with cementitious materials such as polyphosphate pure calcium aluminate cement and other binders. It is a binder itself with good adhesion. The presence of 2CaO.Al3O2 enhances the ability of the gunning material to adsorb on the furnace lining wall.

[0021] If 2CaO.SiO2 or 3CaO.SiO2 clinker is directly used as the aggregate of gunning and repairing materials, since the melting point of 2CaO.SiO2 or 3CaO.SiO2 is >2000℃, it has better anti-corrosion effect as gunning and repairing materials.

[0022] For semi-steel blowing furnaces and low silicon [Si] <0.5% molten iron blowing, taking cost into consideration, a mixture of limestone and quartz sand is preferably used as aggregate, and the ratio of CaO to SiO2 is 2:1 or 3:1 or the ratio of CaO to SiO2 is near 2:1 or 3:1.

[0023] When smelting high silicon molten iron with [Si]>0.5%, CaO material can also be used alone as aggregate for gunning material.

[0024] According to the construction requirements of the repair material and the gunning material, adjust the corresponding type of admixture and its addition amount to obtain the repair material and the gunning material required by the process.

[0025] The rebound material during the furnace repair operation and the gunning material eroded during the blowing process enter the slag, which can increase the amount of (3CaO.SiO2 or 2CaO.SiO2) or the CaO content in the slag. 3CaO.SiO2, 2CaO.SiO2 and CaO are solid phosphorus phases, which increases the dephosphorization capacity of the slag, reduces the amount of lime used, and the furnace repair material is reused for a second time.

[0026] Beneficial Effects

[0027] The technical solution of the present invention adopts a mixture of powdered CaO raw material and SiO2 raw material as aggregate or directly adopts CaO, 2CaO.SiO2, 3CaO.SiO2 clinker as aggregate to produce the repairing furnace charge, which can fully meet the requirements of the spraying and repairing process of the converter, electric furnace, RH refining furnace, and ladle lining; the rebound material during the spraying and repairing operation and the eroded spraying and repairing material enter the molten steel or slag in the furnace or ladle, which can increase the (3CaO.SiO2+2CaO.SiO2) or CaO content in the slag, increase the dephosphorization capacity of the slag, reduce the amount of lime, purify the molten steel, and reuse the repairing furnace charge. Since the mixture of powdered CaO raw material and SiO2 raw material or 3CaO.SiO2, 3CaO.SiO2 silicate clinker as aggregate is much cheaper than sintered magnesia or fused magnesia, and can be reused, the steelmaking container repairing material proposed by the present invention has a high cost performance. DETAILED DESCRIPTION

[0028] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0030] Prepare the aggregates and adjust the type and amount of admixtures according to construction needs to obtain the repair materials and spraying materials required by the process.

[0031] Example 1

[0032] Gunning material of the technical solution of the present invention

[0033] The limestone and quartz sand are crushed, ground and sieved to obtain limestone particles and quartz sand of Φ1mm--6mm and limestone particles and quartz sand particles of Φ0.2mm--1mm respectively; the silicate cement clinker is made into fine powder with a particle size of less than 0.074mm.

[0034] According to the gunning material CaO\SiO2 of 2, add 35 parts of limestone 1mm≤<6mm, 40 parts of 0.2mm≤<1mm, 12 parts of quartz sand 1mm≤<5mm, 10 parts of 0.2mm≤<1mm and 9 parts of admixture into the mixer; mix well and then go through the steps of testing and packaging.

[0035] The admixture consists of the following ingredients in parts by weight: 10 parts of silicate cement clinker with a particle size less than 0.074 mm, 5 parts of asphalt with a particle size ≤ 1 mm, 2.5 parts of slaked lime with a particle size ≤ 400 mesh, 1.0 part of silicon micropowder, 0.5 part of carboxymethyl cellulose, and 0.2 part of sodium dodecyl sulfate.

[0036] The actual measurement shows that the CaO\SiO2 of the gunning material in this embodiment is 2.

[0037] Example 2

[0038] Repair material of the technical solution of the present invention

[0039] The limestone and quartz sand are crushed, ground and sieved to obtain limestone particles and quartz sand with a diameter of 1mm--4mm and limestone particles and quartz sand particles with a diameter of 0.2mm--1mm respectively.

[0040] In a mixer, 35 parts of limestone particles with a particle size of 1mm≤<4mm, 40 parts of particles with a particle size of 0.2mm≤<1mm, 12 parts of quartz sand particles with a particle size of 1mm≤<4mm, 10 parts of particles with a particle size of 0.2mm≤<1mm, and 9.5 parts of admixture are added according to weight proportion; after uniform mixing, the mixture is completed through testing and packaging.

[0041] The admixture is composed of the following ingredients by weight: 15 parts of silicate cement clinker with particle size ≤ 1mm, 5 parts of asphalt with particle size ≤ 1mm, 2.5 parts of slaked lime with particle size ≤ 400 mesh, 1.0 part of silica powder, 1.0 part of paper fiber, and 2.5 parts of complex magnesium aluminum sol.

[0042] The CaO\SiO2 content of the repair material in this embodiment was measured to be 2.

[0043] Example 3

[0044] The specific components of ladle gunning material are as follows:

[0045] 1-3mm limestone aggregate 32%;

[0046] 0-1mm limestone aggregate 37%;

[0047] 325 mesh limestone powder 19%;

[0048] Portland cement 10%;

[0049] Oxalic acid 1%;

[0050] Silica powder 1%.

[0051] Example 4

[0052] Example 1 Specific construction method of gunning material

[0053] The gunning material prepared in Example 1 of the present invention is added into a high-pressure material tank, and the air source and water source are connected. The air pressure is greater than 0.5MPa. A trial spraying is first performed, and the water volume is adjusted to a position where the gunning material can adhere and does not flow. The water volume is 8-15wt%. During the gunning, the spray gun is perpendicular to the spraying surface, and the nozzle is slowly moved to ensure that the thickness of the spraying surface is uniform. The thickness of the spraying is 100-200mm per time. After sintering for 10-20 minutes after spraying, the slag splashing furnace protection operation is carried out.

[0054] Example 5

[0055] Construction method of repair material prepared in Example 2

[0056] When using the repair material of Example 2, pour the repair material into the converter and shake the converter to allow it to flow to the areas of the steelmaking converter where hot repairs are required, such as charging, tapping, large surfaces and bottom, and sinter for 10-20 minutes relying on the heat in the converter, and then implement slag splashing and furnace protection operations.

[0057] After the construction of the gunning material and repair material prepared by the technical solution of the present invention, it has been verified through production that the service life of the gunning material and repair material can reach or approach that of MgO-quality repair material, and the service life of a gunning repair can reach 3-10 furnaces; the amount of lime used per ton of steel is reduced by an average of about 1kg / t of steel.

[0058] Although the present invention has been described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Based on the principles of the present invention, the technical personnel skilled in the art make various changes in process parameters and details such as the selection of the type of calcareous raw material or siliceous raw material, the ratio and particle size between the calcareous raw material and the siliceous raw material, the addition or non-addition of admixtures, the type and amount of admixtures, the specific furnace repair, the sintering time after repair, etc., and the process adjustment schemes made should all fall within the scope of protection of the technical solution to be protected by the claims of the present invention.

Claims

1. The present invention is a calcium-silicon furnace filler material, which is composed of aggregate and additives (binding agent 0-2%, coagulant 0-2%, sintering aid and mineralizer 0-5%, plasticizer 0-3%, dispersant 0-1%, explosion-proof agent 0-0.03%), characterized in that: The aggregate is composed of 60-100% of calcium raw materials and 0-50% of silicon raw materials.

2. The calcium-silicon furnace filler material according to claim 1, characterized in that: The ratio of CaO to SiO2 in the silicon-calcium furnace filler is 2:1 or 3:1 or the ratio of CaO to SiO2 is near 2:1 or 3:

1.

3. The calcium-silicon furnace filler material according to claim 1, characterized in that: The calcium raw material is one or both of limestone and quicklime.

4. The calcium-silicon furnace filler material according to claim 1, characterized in that: The siliceous raw material is one of quartz sand, silica and quartz mineral.

5. The calcium-silicon furnace filler material according to claim 1, characterized in that: The aggregates of the calcium raw materials and the silicon raw materials can be replaced by 2CaO.SiO2 clinker or 3CaO.SiO2 clinker or calcium silicate clinker mainly composed of 3CaO.SiO2 and 2CaO.SiO2.

6. The silicon-calcium furnace filling material according to claim 1, characterized in that: The admixture is one or more of sodium dodecyl sulfate, sodium tripolyphosphate, sodium hexametaphosphate, silicon powder, water glass, phenolic resin, silicate cement clinker, calcium aluminate cement, talcum powder, B2O3, silicon carbide, spherical asphalt, kerosene, diesel, engine oil, anthracene oil and LiCO3, talcum powder, B2O3, silicon carbide, silicon powder, carboxymethyl cellulose, hemp fiber, slaked lime powder, a-Al2O3 powder, complex magnesium aluminum sol, silica ash, lithium bentonite, and paper fiber.

7. The calcium-silicon furnace filler material according to claim 1, characterized in that: According to the construction needs, the corresponding repair materials for converters, electric furnaces, RH refining furnaces, flame gunning materials, dry gunning materials, wet gunning materials and ladle repair materials are obtained by adjusting the admixtures.

8. A method for using a silicon-calcium furnace charge, characterized in that: After the converter or electric furnace gunning operation, slag splashing and furnace protection operation are carried out after sintering for 10-20 minutes; after the converter or electric furnace repair operation, the molten slag is covered on the repair area and sintered for 10-20 minutes.