CN1418852A - Phosphoric acid and spinel combined high aluminia pouring material - Google Patents
Phosphoric acid and spinel combined high aluminia pouring material Download PDFInfo
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- CN1418852A CN1418852A CN 02158761 CN02158761A CN1418852A CN 1418852 A CN1418852 A CN 1418852A CN 02158761 CN02158761 CN 02158761 CN 02158761 A CN02158761 A CN 02158761A CN 1418852 A CN1418852 A CN 1418852A
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- alumina
- phosphoric acid
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Abstract
The present invention belongs to the field of refractory material, specially, it is suitable for producing phosphoric acid combined high-aluminium pouring material. It is characterized by that it uses electrocast spinel as coagulation accelerator or phosphoric acid combined pouring material, its main raw material is a high-grade high-alumina, and its secondary raw material is electrocast magnesia-alumina spinel and phosphoric acid. Said inention is easy to construct and easy to remove form, and has higher strength, after the form of removed for 3 days, it is water resistant.
Description
The technical field is as follows:
the invention belongs to the field of refractory materials, and is particularlysuitable for producing phosphoric acid combined high-alumina castable.
Background art:
the main coagulant of the phosphoric acid combined high-alumina castable commonly used in China at present is high-alumina cement and MgO fine powder. The use of high alumina cement as the set accelerator results in a reduction in the refractoriness and other properties of the casting material due to the introduction of a certain amount of CaO. When fine MgO powder is used as a coagulant, the fine MgO powder can react with phosphoric acid to generate dust at normal temperature to coagulate and harden the refractory castable, but because MgO reacts with phosphoric acid quickly, the dosage of MgO must be strictly controlled, which brings difficulties to the processes of pouring construction, demoulding, baking and the like, and researches show that if MgO is used as a coagulant, the hardened strength is very low.
The invention content is as follows:
the invention aims to find a material which replaces high-alumina cement or MgO fine powder as a coagulant, so that the material can play a role in accelerating coagulation, obtain a proper coagulation speed, facilitate construction and greatly improve various performance indexes of a castable.
The invention relates to a phosphoric acid combined spinel high-alumina castable, which is characterized in that electric melting spinel is used as a coagulant of the phosphoric acid combined castable, high-alumina cement and MgO fine powder which are used as the phosphoric acid coagulant are not added, and a novel castable product, namely the phosphoric acid combined spinel high-alumina castable, is developed through reasonable grading and process optimization, wherein the main raw material is special grade or firstgrade high-alumina bauxite, and the high-alumina bauxite comprises the following chemical components: al (Al)2O3The content is more than 75 percent, CaO is less than or equal to 0.6 percent, and Fe2O3Less than or equal to 2.0 percent; the secondary raw materials are fused magnesia-alumina spinel and phosphoric acid, and the fused magnesia-alumina spinel comprises the following chemical components: al (Al)2O340-58% of MgO, 40-58% of SiO2≤1.8％，Fe2O3Not more than 1.5 percent, and the volume density rho is not less than 3.30g/cm2(ii) a The concentration of phosphoric acid used was 42.5%. The content of the fused magnesia-alumina spinel in the castable is 9-15%, the content of the fused magnesia-alumina spinel is optimal for 11-13%, the content of the phosphoric acid is 10-14%, the content of the phosphoric acid is optimal for 11.5-12.5%, and the rest is high bauxite.
In order to achieve the most reasonable particle size distribution, bauxite particle aggregates are classified into three categories: coarse aggregate of 5-3 mm, medium aggregate of 2-3mm, fine aggregate of less than 2mm, and powder of less than 0.088 mm.
Because the magnesium oxide exists in the matrix of the spinel, the reaction speed of the phosphoric acid and the magnesium oxide is reduced relative to the reaction speed of pure magnesium oxide and the phosphoric acid, so that the castable is not inhibited by adding a retarder because the reaction speed of the magnesium oxide and the phosphoric acid is too high to be constructed. Therefore, the excellent effect of accelerating the coagulation can be achieved by using proper amount of the alkaline electrically-fused spinel.
The chemical reaction equation is as follows:
the production process of the phosphoric acid combined spinel high-alumina castable is shown in figure 1, wherein pug is mixed in a wet mill. After various reasonably matched materials are accurately weighed and kneaded, the various materials are homogenized through convection, diffusion and shearing, and the particles are combined with a binding agent and the like, so that the mud has good forming performance, and meanwhile, the particles in the mud are prevented from being re-crushed, certain materials are prevented from being lost or the mud is prevented from being obviously reacted and deteriorated in the re-kneading process, and the various materials in the mud are well combined. The mixing is carried out in a wet mill, and even and compact pug can be obtained although the yield is low, the power consumption is high, the particles are crushed again and the like.
When the lean material is added with the phosphoric acid solution to prepare a mixture, impurities such as metallic iron in the lean material react with acid to form gas, so that the mixture is swelled and loose in structure, and the strength of a hardened body is reduced, so the lean material needs to be trapped, namely, after part of acid is added to mix the mixture, the mixture is kept still for at least 16 hours at a temperature of more than 10-28 ℃, and the cover is tightly closed to prevent the phosphoric acid from evaporating, so that the gas is fully escaped, and then the residual acid is added to mix the mixture.
After the casting material is formed, proper measures are taken to carry out maintenance and accelerate the hardening according to the hardening characteristics of the binding agent, and the casting material combined by phosphoric acid is firstly maintained in the air with the temperature of more than 20 ℃ for more than 3 days and then baked.
The castable should be baked before first use, and the castable has different dehydration amounts at different temperatures. Under 110 deg.C, a large amount of free water is removed, the temperature of the castable combined with phosphoric acid is slowly raised at the speed of 10-20 deg.C/h under 110 deg.C, and the temperature is kept for 24-48 hours under 110 deg.C. In order to reduce the temperature difference between the inside and the outside, the surface evaporation is not too fast, and the method of reducing the flow rate or controlling the warm air flow, namely the operation of warming fire and stabilizing fire can be adopted. And (3) heating to 350-450 ℃, wherein the heating is not too fast and too fast, and enough heat preservation time is needed. If the temperature is not enough at 350-450 ℃, the temperature is raised too rapidly, and problems are easy to occur, so the temperature is raised to 450 ℃ at 20-30 ℃/h, the temperature is maintained for 24 hours, and then the temperature is raised to the working temperature at 20-40 ℃/h.
The product performance is as follows: volume weight: when dried at 110 ℃ is 2.9g/cm3After baking at 450 ℃ 2.7g/cm3(ii) a Strength: the material has a three-day flexural strength of not less than 4MPa, a compressive strength of not less than 30MPa, a flexural strength of not less than 3.5MPa after being dried at 110 ℃, a compressive strength of not less than 45MPa, a flexural strength of not less than 5MPa after being baked at 450 ℃, and a flexural strength ofThe compressive strength is more than or equal to 45MPa, and the compressive strength is more than or equal to 100MPa after the firing at 1450 ℃ for 3 h; degree of refractoriness: 1790 deg.C; high temperature volume stability: the shrinkage of the re-burning line is less than orequal to 0.9 percent after the re-burning at 1450 ℃ for 3 h; thermal shock resistance: the performance is excellent, and the compressive strength is basically kept unchanged after the material is quenched and rapidly heated in water for 10 times.
The spinel high-alumina castable material combined with phosphoric acid is easy to construct and demold, has high strength, is not afraid of moisture and water immersion after being demolded for three days, is greatly superior to the high-alumina castable material using high-alumina cement and fine powder as a coagulant, and has the maintenance strength, the drying strength and the strength after burning which are 2-3 times of the compressive strength of the existing phosphoric acid combined high-alumina castable material in China. The product has excellent thermal shock resistance, slag corrosion resistance longer than that of the silicon lining by more than one time, and water resistance before baking.
Description of the drawings: FIG. 1 is a flow chart of a production process of phosphoric acid combined spinel high-alumina castable
Detailed Description
Taking special grade alumina as shown in figure 1: 27.5 percent of coarse particles with the diameter of 3-5mm, 27.5 percent of medium particles with the diameter of 2-3mm, 27 percent of fine particles with the diameter of 0-2mm, 6 percent of fine powder with the diameter of less than 0.088mm and 12 percent of alkaline fused spinel with the diameter of less than 0.088 mm. Phosphoric acid was added, with an additional 14% of the total weight. The sample preparation adopts the vibration molding of a vibration table. And demolding the sample one day after molding, and naturally curing for two days, namely three days after the molding anddemolding. Drying at 110 ℃, drying at 450 ℃, calcining at 1300 ℃ for 3h, calcining at 1450 ℃ for 3h, and cutting and grinding to obtain the finished product. The main performance indexes of the obtained product are as follows:
volume weight (g/cm)3) (110 ℃ oven drying) 2.89
Strength (MPa) rupture resistance 7.8 after natural curing for three days
Resistance to compression 32.5
Bending resistance of 10.8 under 110 ℃ for 24h
Resist 45.2 of pressure
Breaking resistance of 12.3 times at 450 ℃ for 24h after baking
Resistance to compression 56.4
Strength (MPa) rupture 15.8 after 1300 ℃ x 3h firing
Resistance to compression 84.6
Bending resistance of 20.2 in strength (MPa) after being fired at 1450 ℃ for 3h
Resist 120.8 of pressure
Refractoriness (DEG C) 17901450 ℃ for 3h after burning, re-burning linear shrinkage (%) 0.8 thermal shock resistance (1450 ℃ for 3h) 62 after natural curing for three days, the water resistance is good
Claims (6)
1. The phosphoric acid combined spinel high-alumina castable is characterized by comprisingThe invention takes the electric melting spinel as the coagulant of the phosphoric acid combined castable, the main raw material is special grade or first grade high bauxite, the chemical composition of the high bauxite is: al (Al)2O3The content is more than 75 percent, CaO is less than or equal to 0.6 percent, and Fe2O3Less than or equal to 2.0 percent; the secondary raw materials are fused magnesia-alumina spinel and phosphoric acid, and the fused magnesia-alumina spinel comprises the following chemical components: al (Al)2O340-58% of MgO, 40-58% of SiO2≤1.8％，Fe2O3Less than or equal to 1.5 percent, and the volume density p is more than or equal to 3.30g/cm2(ii) a The concentration of the used phosphoric acid is 42.5%, the dosage of the electric melting magnesia-alumina spinel in the casting material is 9-15%, the dosage of the phosphoric acid is 10-14%, and the rest is on the high alumina.
2. The high alumina castable according to claim 1, wherein the fused magnesia alumina spinel is used in an amount of 11 to 13% preferably, the phosphoric acid is used in an amount of 11.5 to 12.5% preferably, and the balance is high alumina.
3. The high-alumina castable according to claim 1 or 2, wherein the high-alumina bauxite granular aggregate is divided into three types: coarse aggregate of 5-3 mm, medium aggregate of 2-3mm, fine aggregate of less than 2mm, and powder of less than 0.088 mm.
4. The high-alumina castable according to claim 3, wherein after part of the acid-mixed mixture is added in the production process, the castable is kept still for 16-28 hours at a temperature of 10-28 ℃ or higher, the covering is tight, the phosphoric acid is prevented from evaporating, gas is enabled to escape sufficiently, and then the residual acid is added for mixing.
5. The high-alumina castable according to claim 4, wherein after being molded, the castable is first cured in air at 20 ℃ or higher for 3 days or longer and then baked.
6. The high-aluminum castable according to claim 5, wherein the castable is baked before first use, the temperature is raised at a rate of 10-20 ℃/h below 110 ℃, the temperature is slowly raised, the temperature is maintained at 110 ℃ for 24-48 hours, the temperature is raised to 350-450 ℃, the temperature is raised to 450 ℃ at 20-30 ℃/h, the temperature is maintained for 24 hours, and then the temperature is raised to the working temperature at 20-40 ℃/h.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 02158761 CN1418852A (en) | 2002-12-26 | 2002-12-26 | Phosphoric acid and spinel combined high aluminia pouring material |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 02158761 CN1418852A (en) | 2002-12-26 | 2002-12-26 | Phosphoric acid and spinel combined high aluminia pouring material |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101397212B (en) * | 2008-09-16 | 2011-07-27 | 高树森 | Refractory castable of nanocomposite oxide ceramic combining alumina-spinelle and preparation method thereof |
| CN101580398B (en) * | 2009-06-29 | 2011-11-02 | 河南省耕生耐火材料有限公司 | Ladle kerb casting material and ladle kerb preparation method thereof |
| CN110171961A (en) * | 2018-12-20 | 2019-08-27 | 瑞泰科技股份有限公司 | A kind of aluminium chrome-magnesite firebrick and preparation method thereof |
| CN111995408A (en) * | 2020-08-18 | 2020-11-27 | 武汉钢铁集团耐火材料有限责任公司 | Repairing material and repairing method for working layer at bottom of molten iron tank |
-
2002
- 2002-12-26 CN CN 02158761 patent/CN1418852A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101397212B (en) * | 2008-09-16 | 2011-07-27 | 高树森 | Refractory castable of nanocomposite oxide ceramic combining alumina-spinelle and preparation method thereof |
| CN101580398B (en) * | 2009-06-29 | 2011-11-02 | 河南省耕生耐火材料有限公司 | Ladle kerb casting material and ladle kerb preparation method thereof |
| CN110171961A (en) * | 2018-12-20 | 2019-08-27 | 瑞泰科技股份有限公司 | A kind of aluminium chrome-magnesite firebrick and preparation method thereof |
| CN111995408A (en) * | 2020-08-18 | 2020-11-27 | 武汉钢铁集团耐火材料有限责任公司 | Repairing material and repairing method for working layer at bottom of molten iron tank |
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