Synthetic ferro-aluminum spinel and its preparation method

A ferroaluminum spinel and compound technology, which is applied in the field of refractory materials, can solve the problems of easy occurrence of thermite reaction, complicated process, high purity, etc., and achieve the effect of cheap raw material, low reaction temperature and simple process

Inactive Publication Date: 2006-04-26
WUHAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Iron-aluminum spinel (FeO.Al 2 o 3 ) exists very rarely in nature, and the iron-aluminum spinel is generally synthesized by electrofusion, such as Al 2 o 3 and Fe as raw materials (Journal of Magnetism and Magnetic Materials, 2003, 264: 264-274), but the reaction process is difficult to control, and the reaction is not sufficient
The method of mechanochemical synthesis of iron-aluminum spinel is to use planetary mill to combine Al and Fe 3 o 4 Grinding for a certain period of time, and then reacting and synthesizing in an argon atmosphere at 1200 ° C (Materials Chemistry and Physics, 2002, 76: 104-109), but using a two-step treatment method, the process is complicated, and the thermite reaction is easy to occur, resulting in the final product difficult to control
Using special-grade bauxite, iron scale and graphite as raw materials, iron-aluminum spinel was synthesized by reaction sintering method (Liu Huiming et al. Refractories, 2003, 37(6): 333-335), however, the synthesis temperature is higher than 1550°C and Low purity, such as about 10% Fe remaining in the final phase 2 o 3 and Al 2 o 3 , leading to an increase in production costs and a decline in grade

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] According to the molar ratio of Al ion and Fe ion is the ratio of 2:1, the particle size is 180 mesh Al(OH) 3 、Al 2 o 3 .H 2 Aluminum-containing compounds of O and Fe with a particle size of 180 mesh 2 o 3 , FeO mixed with iron-containing compounds. Where: Al(OH) 3 The content in aluminum-containing compounds is 35-45wt%, Fe 2 o 3 The content in iron-containing compounds is 65-75 wt%. The process conditions are as follows: dry mix the above raw materials in a planetary mill, then add 2-4wt% methyl cellulose, mix for 30-180 minutes, machine-press at a pressure of 40-200Mpa, dry in an oven at 110°C for 24 Hours, at a heating rate of 1-5°C / min, raise the temperature to 1200-1500°C in an atmosphere of buried carbon, keep it warm for 30-240 minutes, and take it out after natural cooling.

[0010] The phase in the product tested by X-ray diffraction is FeAl 2 o 4 . Its performance is detected as a volume density of 3.70cm 3 , The apparent porosity is 4%.

Embodiment 2

[0012] According to the molar ratio of Al ions and Fe ions at a ratio of 2:1, corundum fine powder with a particle size of 325 mesh, Al(OH) 3 、Al 2 o 3 .H 2 Aluminum-containing compounds of O and Fe with a particle size of 180 mesh 2 o 3 , FeO mixed with iron-containing compounds. Among them: the content of corundum fine powder in the aluminum-containing compound is 37-45wt%, Al(OH) 3 The content in aluminum-containing compounds is 25-30wt%, Al 2 o 3 .H 2 The content of O in the aluminum-containing mixture is 26-35wt%; Fe 2 o 3 The content in iron-containing mixture is 65-75wt%. The process conditions are as follows: dry mix the above raw materials in a planetary mill, then add 3-5wt% glycerin, mix for 30-120 minutes, press isostatically under a pressure of 200-400Mpa, and dry in an oven at 110°C for 24 hours. Then, it is fired at a heating rate of 1-5°C / min under a carbon-burying atmosphere at a firing temperature of 1300-1600°C, kept at a temperature of 30-120 min...

Embodiment 3

[0015] According to the ratio that the molar ratio of Al ion and Fe ion is 2: 1, corundum fine powder with a particle size of 180 mesh, super alumina with an alumina content of 80wt%, Al(OH) 3 、Al 2 o 3 .H 2 Aluminum-containing compounds of O and 325 mesh Fe 2 o 3 , FeO, Fe 3 o 4 mixed with iron-containing compounds. Among them: the content of corundum in aluminum-containing compounds is 22-26wt%, Al(OH) 3 The content in aluminum-containing compounds is 15-20wt%, Al 2 o 3 .H 2 The content of O in aluminum-containing compounds is 25-30wt%, and the content of super alumina in aluminum-containing compounds is 25-35wt%; Fe 2 o 3 The content in iron-containing compounds is 45-55wt%, Fe 3 o 4 The content in the iron-containing compound is 30-40 wt%, and the content of FeO in the iron-containing compound is 10-20 wt%. The process conditions are as follows: dry mix the above raw materials in a planetary mill, then add 3-5wt% aluminum sol, mix for 120-180 minutes, machine...

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Abstract

The present invention relates to Fe-Al spinel and its preparation process. The technological scheme of the present invention is the Fe-Al spinel preparing process including the steps of: mixing Al containing compound and Fe containing compound in the molar Al/Fe ratio of 2 and adhesive in 1-6 wt% for 5-180 min; forming and drying at 90-120 deg.c for 20-30 hr; heating in carbon atmosphere and temperature raising speed of 0.5-10 deg.c/min at 1100-1700 deg.c for 5-600 min; and naturally cooling. The present invention has the advantages of simple technological process, low reaction temperature and cheap material. Under the sintering temperature, all the Al and Fe components are converted into FeAl2O4, and the sintered product has apparent porosity lower than 5 %.

Description

1. Technical field [0001] The invention belongs to the technical field of refractory materials. In particular, it relates to a synthetic iron-aluminum spinel and a preparation method thereof. 2. Background technology [0002] The traditional cement kiln firing zone 7 alkaline material magnesia chrome brick has excellent high temperature resistance and corrosion resistance, but under the action of alkali, the stable trivalent chromium is converted into hexavalent chromium with strong oxidation ability, which is harmful to human body. It is very large, which limits the application of magnesia-chrome bricks. With the enhancement of people's environmental awareness, it is imperative to develop low-chromium or chrome-free basic bricks for cement kilns. For chromium-free basic bricks, if a stable kiln skin can be formed on the hot surface of the furnace lining, the life of the furnace lining can be significantly improved. The French Refa Group (RHI or Refratechnik) found that th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/44C04B35/66C01F7/04
Inventor 金胜利李亚伟李远兵李楠敖进清
Owner WUHAN UNIV OF SCI & TECH
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