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Powder composition for castable refractory and premixed material comprising the same, method for applying premixed material and refractory hardene product therefrom

a technology of casting refractory and powder composition, which is applied in the direction of ceramic shaping apparatus, manufacturing tools, etc., can solve the problems of high casting cost, reduced strength of the resultant refractory body, and production in advan

Inactive Publication Date: 2005-10-27
TAIKO ROZAI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0008] Accordingly, an object of the present invention is to provide a castable refractory powder composition containing alumina cement capable of providing a premixed material by tempering with water, which can keep flowability for a long period of time.
[0009] Another object of the present invention is to provide a premixed material containing alumina cement, which can keep flowability for a long period of time.

Problems solved by technology

However, these heat-hardening methods are disadvantageous in high casting cost because of energy loss due to heat-hardening, and periodic maintenance due to the thermal deformation of molds, etc.
They are also disadvantageous in the reduced strength of the resultant refractory body due to rapid water removal by heating.
However, because the alumina cement slurry is hardened with time, it cannot be produced in advance, but should be prepared at the time of casting.
It can be stored and used days after gunning without discarding a castable refractory remaining in an apparatus because of a extremely long working time.

Method used

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  • Powder composition for castable refractory and premixed material comprising the same, method for applying premixed material and refractory hardene product therefrom
  • Powder composition for castable refractory and premixed material comprising the same, method for applying premixed material and refractory hardene product therefrom

Examples

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reference example 1

[0049] With respect to aqueous solutions of various hydration stoppers for alumina cement, the measurement results of their pH are shown in Table 1. The concentrations of the hydration stoppers whose pH was measured are as follows. For comparison, the pH of trisodium citrate is also shown.

TABLE 1Hydration StopperpHCitric Acid1.8(1)Sodium Dihydrogen Citrate3.6(1)Basic Aluminum Lactate4.6(1)(TAKICERAM GM)Tartaric Acid1.6(1)Polyacrylic Acid2.1(1)Chelating Agent EDTA4.3(1)Sodium Hexametaphosphate6.0(1)Acidic Sodium Hexametaphosphate1.3(1)Sodium Ultrapolyphosphate1.4(1)Phosphoric Acid0.9(2)Aluminum Phosphate1.4(3)Boric Acid4.3(1)Trisodium Citrate8.2(1)

Note:

(1)pH was measured on 5 g of powder in 100 cm3 of water.

(2)pH was measured on 5 cm3 of a phosphoric acid solution (solid concentration: 85% by mass) in 95 cm3 of water.

(3)pH was measured on 5 cm3 of an aluminum phosphate solution (solid concentration: 73% by mass) in 95 cm3 of water

examples 1 to 9

, COMPARATIVE EXAMPLES 1 TO 3

[0050] Various hydration stoppers shown in Table 1 were added to a castable refractory powder composition having a formulation shown in Table 2, and the resultant composition was tempered with 6.5% by mass (outer percentage) of water in a utility mixer to prepare a premixed material. The resultant premixed material was stored at 25±1° C. The relations between the pH and storability of the resultant premixed materials are shown in Table 3.

TABLE 2FormulationComponents(% by mass)Refractory AggregateElectrofused Alumina (Particle Size: 8 to 5 mm)7Electrofused Spinel (Particle Size: 5 to 1 mm)34Electrofused Alumina (Particle Size: 1 mm or less)24Fine Refractory PowderElectrofused Alumina (Particle Size: 200 μm or less)7Silicon Carbide (Particle Size: 200 μm or less)15Calcined Alumina (Particle Size: 10 μm or less)7Carbon Black (Particle Size: 1 μm or less)1Amorphous Silica (Particle Size: 1 μm or less)2Pitch1Alumina Cement (JIS Class 1)2Dispersing Agentβ-Na...

example 24

[0056] The castable refractory powder composition having the formulation of Example 1 shown in Table 3 was tempered with 6.5% by mass of water in a large-vortex mixer, to produce 20 tons of a premixed material. After the resultant premixed material was stored at room temperature (about 15 to 23° C.) for 9 days, it was conveyed to a casting site in a steel works, and cast into a large trough of a blast furnace.

[0057] Using the casting apparatus shown in FIG. 1(a), the premixed material was cast. The specification of the casting apparatus is shown in Table 5.

TABLE 5PartsSpecificationPump 3Double-piston pump (maximum ejection pressure: 25 MPa)Pipe 5Steel pipe of 100 mm in inner diameter and 30 m in lengthHydration-Improved nozzle body with ring having 16 apertures thereinStopper-InjectingMeans 8MeteringTriple non-pulsating plunger pumpPump 6Flow rate: 0.5 to 33 L / min,Maximum ejection ressure: 10 MPaLineStatic mixer having two mixing elements twisting by 180°Mixer 9clockwise and coun...

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Abstract

A premixed material is obtained by tempering a castable refractory powder composition comprising refractory aggregate, fine refractory powder, alumina cement, a dispersing agent and an alumina cement hydration stopper with water. The hydration stopper is acidic in a state of an aqueous solution. The amount of the hydration stopper is controlled such that the premixed material has a pH of 2 to 7. Immediately after adding and mixing an alumina cement hydration starter to the premixed material, the resultant mixture is cast into a mold. The addition of the hydration starter can be carried out 5 days or more after the production of the premixed material.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a castable refractory powder composition usable for linings of vessels for molten metals such as troughs for blast furnaces, ladles, tundishes, etc., a premixed material prepared therefrom, a method for hardening the premixed material at room temperature without heating, and a hardened refractory body obtained by such a method. BACKGROUND OF THE INVENTION [0002] Premixed castable refractories (hereinafter referred to as “premixed materials”), which are obtained by tempering castable refractory powder compositions with water or other tempering liquids in advance in other sites than casting sites, such as factories, etc., and transported to the casting sites, have recently become widely used as refractories for linings of vessels for molten metals such as troughs for blast furnaces, ladles, tundishes, etc. [0003] Though the premixed materials suffer from new problems such as hardening with time, the separation of aggregate...

Claims

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Application Information

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IPC IPC(8): C04B28/06C04B35/66
CPCC04B35/62665C04B2235/5436C04B2235/5427C04B2235/424C04B2235/3873C04B2235/3418C04B2235/3222C04B2235/3217C04B2235/3206C04B28/06C04B35/66C04B14/30C04B20/0076C04B2103/10C04B2103/20C04B22/0093C04B24/06C04B40/0028C04B40/0658C04B22/062C04B24/2641C04B2103/0094C04B22/0013C04B22/085C04B22/10C04B22/16
Inventor OBA, JUNTANAKA, KUNIOTAKAHASHI, NOBUYUKIFUJISAKI, TAKASHI
Owner TAIKO ROZAI