Method for preparing magnesia-alumina spinel powder through low-temperature solid reaction process

A technology of magnesium-aluminum spinel powder and solid-phase reaction method is applied in the field of preparing magnesium-aluminum spinel powder by low-temperature solid-phase reaction method, and can solve the problems of long production cycle, coarse and uneven particles, and high energy consumption

Inactive Publication Date: 2012-10-03
DALIAN JIAOTONG UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The former has simple process, high temperature (generally higher than 1400-1600°C), high energy consumption, large output, coarse and uneven particles (generally more than tens of microns); the latter has fine process, cumbersome technology, long production cyc

Method used

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  • Method for preparing magnesia-alumina spinel powder through low-temperature solid reaction process
  • Method for preparing magnesia-alumina spinel powder through low-temperature solid reaction process
  • Method for preparing magnesia-alumina spinel powder through low-temperature solid reaction process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Example 1, a method for preparing magnesia-aluminum spinel powder by a low-temperature solid-state reaction method is to weigh 21.15 grams of gibbsite (AlOOH), 5 grams of magnesium oxide (MgO), and add 1 gram of AlF 3 . 3.5H 2 O was ground in a ceramic mortar to obtain a loose powder, and kept in a high-temperature furnace at 900°C to 1200°C for 3 hours to obtain a pure-phase magnesium-aluminum spinel whose primary particles were (nearly) regular octahedral crystals Stone powder, high temperature solid phase reaction:

[0032]

[0033]

[0034]

Embodiment 2

[0035] Example 2, a method for preparing magnesia-aluminum spinel powder by a low-temperature solid-state reaction method is to weigh 12.8 grams of γ-alumina (Al 2 o 3 ), 5 grams of MgO, plus 1 gram of AlF 3 . 3.5H 2 O and 15mL ethanol in a ceramic mortar, grind to obtain a loose powder, or fully mix, disperse, dry and then grind, and keep it in a high-temperature furnace at 900 ° C ~ 1200 ° C for 3 hours to obtain part of the primary The particles are pure-phase magnesium-aluminum spinel powders with regular octahedral crystals. The high-temperature solid-state reaction is as follows:

[0036]

Embodiment 3

[0037] Example 3, a method for preparing magnesia-aluminum spinel powder by a low-temperature solid-state reaction method is to weigh aluminum sulfate Al that can generate 12.8 grams of alumina 2 (SO 4 ) 3 or its hydrate, add 1 g NH 4 F and an appropriate amount of water to dissolve it completely, and add an appropriate amount of ammonia or urea aqueous solution under constant stirring until all aluminum ions completely form AlOOH or Al(OH) 3 Or its mixture, evaporate or dry at a temperature lower than 60°C, add 5 grams of MgO and grind together to obtain a loose powder, keep it in a high-temperature furnace at 900°C to 1200°C for 3 hours, and obtain some primary particles. The pure-phase magnesia-aluminum spinel powder of regular octahedral crystals, the chemical reactions that occur during the hydrolysis precipitation process are as follows, and the high-temperature solid-phase reactions are as in Example 1:

[0038]

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PUM

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Abstract

The invention discloses a method for preparing magnesia-alumina spinel powder through the low-temperature solid reaction process. Raw material containing aluminum and magnesium is weighted according to the stoichiometric proportion of magnesia-alumina spinels, the weighted raw material is subject to dry-process pretreatment, wet-process pretreatment, saline hydrolysis process pretreatment or saline precipitation process pretreatment to obtain mixture powder as a precursor, the precursor is subject to the heat treatment or roasting at the temperature of 900 to 1,200 DEG C to obtain the magnesia-alumina spinel powder with better dispersibility and pure phase, and part of particles takes the shape of an octahedra. According to the invention, fluorochemicals are taken as mineralizing agents, the effective control on the solid-phase reaction of alumina (or aluminum hydroxide) and marmag (or magnesium hydroxide) at a high temperature is achieved, and the characteristics that the reaction temperature is low, the pure-phase or almost pure-phase magnesia-alumina spinel powder can be manufactured, the chemical purity of the powder can keep the same level with that of the powder before the solid-phase reaction, the granularity of the powder is micron-grade or submicron-grade, and the raw material particles of the powder take the shape of a regular octahedra sometimes are achieved.

Description

technical field [0001] The invention belongs to the field of preparation of inorganic non-metallic materials, and in particular relates to a method for preparing magnesium-aluminum spinel powder by a low-temperature solid-state reaction method. Background technique [0002] Spinel is both magnesium aluminum spinel (MgA1 2 o 4 ) The name of minerals, and the general term for minerals with the same crystal structure, which exist widely in nature. The magnesium aluminum spinel structure belongs to the cubic crystal system, the face-centered cubic lattice, and the Fd3m space group. The saturated structure of magnesium aluminum spinel determines its excellent properties, such as high melting point (2135°C), good corrosion resistance and wear resistance, high chemical stability, good insulation, small thermal expansion coefficient, and high hardness. Its physical properties are between A1 2 o 3 and the physical properties of MgO crystals. [0003] Due to its unique structure...

Claims

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Application Information

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IPC IPC(8): C04B35/443C04B35/63
Inventor 王修慧王程民王富刚宫瑞楼姜文王高涛
Owner DALIAN JIAOTONG UNIVERSITY
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