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A method of adding magnesium-rich spinel powder to prepare zirconia sizing nozzle

A magnesia-rich spinel and sizing nozzle technology is applied in the field of adding magnesia-rich spinel fine powder to prepare zirconia sizing nozzles, which can solve problems such as agglomeration and bonding, reduce porosity and improve thermal shock stability. properties, the effect of reducing the thermal expansion coefficient and elastic modulus

Inactive Publication Date: 2018-11-09
XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Aiming at the defects and deficiencies in the prior art, according to the research results of the National Natural Science Foundation of China project undertaken by the research group "Research on the Fracture Mechanism and Service Life Improvement of Zirconia Calibration Nozzle Stabilizer Desolvation Particles" (Project No. 51372193), the present invention It solves the problem of agglomeration and bonding in the existing zirconia sizing nozzle co-grinding and granulation process, humidification granulation and billet aging process, and can solve the problem of composition adjustment, introduction of spinel phase and prevention of Problems such as stabilizer desolvation further improve the service life of zirconia sizing nozzles

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0019] The present invention adds magnesium-rich spinel powder in the preparation process of the zirconia sizing nozzle. First, it takes advantage of the excellent performance of spinel to prevent the elements in the molten steel from diffusing to the zirconia particles. Synthetic; the second is to prevent the stabilizer magnesium oxide from reacting with alumina to form spinel and prevent further desolvation of the stabilizer in the particles; third, the surplus magnesium oxide stabilizer is finely dispersed in the spinel, which can significantly Prevents the problem of particle adhesion during the hydration and humidification granulation process of magnesium oxide. Experimental data shows that the volume density of the zirconia sizing nozzle prepared by adding magnesium-rich spinel powder is about 3 to 5% higher than the ordinary preparation process of adding magnesium oxide powder, the porosity of the finished product is reduced by 5.0 to 6.5%, and the granulation process Th...

Embodiment 1

[0022] Step one, the preparation of total grinding powder:

[0023] 1) The raw materials include partially stabilized zirconia powder, monoclinic zirconia powder and magnesium-rich spinel powder. The chemical composition of partially stabilized zirconia powder is (wt%): ZrO 2 =95.02, HfO 2 = 2.04, MgO = 2.61, CaO = 0.03, Al 2 O 3 =0.03, loss on ignition is 0.27, particle size is D 95 =49.82μm; the chemical composition of monoclinic zirconia powder is (wt%): ZrO 2 +HfO 2 =98.72 and SiO 2 =0.27, the particle size of monoclinic zirconia is D 50 =1.87μm, D 95 2 %=0.67, Al 2 O 3 %=37.22, particle size composition is D 50 =0.48μm, D 90 =0.97μm.

[0024] According to the proportion of partially stabilized zirconia micropowder, monoclinic zirconia micropowder and magnesium-rich spinel micropowder at a ratio of 48:47:5, the above-mentioned materials are loaded into a polyurethane ball mill tank, and zirconia ceramic balls are used. Totally grind for 24 hours to ensure that the raw materials ...

Embodiment 2

[0032] The difference between this embodiment and embodiment 1 is that the ratio of the amount of partially stabilized zirconia micropowder, monoclinic zirconia micropowder and magnesium-rich spinel micropowder in step one is adjusted to 47:47:6, and magnesium oxide stabilizer is added And the content of pre-synthetic spinel. According to the proportion of the amount of partially stabilized zirconia, monoclinic zirconia and magnesium-rich spinel powder, the above materials are put into a polyurethane ball mill tank, and zirconia ceramic balls are used for grinding for 24 hours to ensure that the raw materials are fully mixed. ; As the content of magnesium oxide stabilizer increases, the firing temperature in step four is adjusted to 1710°C. The average service life of the prepared fine-particle zirconia sizing nozzle reaches 41.6 hours, the highest is 42 hours, and the lowest is 40 hours, which is slightly lower than that of Example 1, and the use performance is stable.

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Abstract

The invention discloses a method for preparing a zirconia sizing nozzle by adding magnesium-rich spinel micropowder. Firing at 1720°C to obtain a zirconia sizing nozzle; the powder includes partially stabilized zirconia powder, monoclinic zirconia powder and magnesium-rich spinel powder, partially stabilized zirconia, monoclinic zirconia and rich The dosage ratio of the magnesium spinel micropowder is (45-50):(45-50):(4-6). The volume density of the zirconia sizing nozzle prepared by the present invention is about 3-5% higher than that of the ordinary preparation process of adding magnesium oxide powder, and the porosity of the finished product is reduced by 5.0-6.5%, and there is no hydration viscosity of magnesium oxide in the granulation process. Agglomeration phenomenon, the service life of zirconia sizing nozzle can reach more than 40 hours. The method solves the problem of agglomeration of hydrated magnesia particles in the process of adding magnesia micropowder stabilizer to monoclinic zirconia during humidification and granulation.

Description

Technical field [0001] The invention relates to a preparation process for preparing a functional refractory material for a device for controlling the flow of molten steel in a continuous casting tundish in the iron and steel metallurgical industry, in particular to a method for preparing a zirconia sizing nozzle by adding magnesium-rich spinel powder. Background technique [0002] The sizing nozzle refers to a functional device made of high-temperature structural ceramic installed at the bottom of the continuous casting tundish. Its main function is to maintain the static pressure of the molten steel in the tundish basically unchanged. The molten steel flows into the mold through the sizing nozzle, and the mold is cooled by a large flow of water to take away the heat released when the molten steel is solidified and solidify the molten steel into a billet. Since the heat taken away by the water cooling of the mold is limited, the amount of molten steel flowing into the mold per un...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/66C04B35/482C04B35/622
CPCC04B35/482C04B35/622C04B2235/3222C04B2235/5436C04B2235/5445
Inventor 薛群虎杨光赵亮
Owner XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY