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Alumina Structural Analysis

Hangzhou JWG Technology Co.Ltd | Updated: Aug 02, 2017

There are two kinds of raw materials used in the experiment: one is high bauxite clinker, is the bauxite mining after mining into the vertical kiln after calcination 1550 ℃ ~ 1600 ℃ after the clinker. Alumina The other is the bauxite homogenization material, is the mining of bauxite ore through the processing, Alumina crushing, grinding, granulation, molding, drying, calcination (1560 ℃ ~ 1600 ℃) prepared clinker. The chemical composition of bauxite clinker and bauxite homogenizer was analyzed by X-ray fluorescence spectrometer. The volume density and apparent porosity were measured by GB / T2997-2000. The phase composition was analyzed by X-ray diffractometer. Microstructure analysis, Alumina transmission electron microscopy using transmission light microstructure analysis.

Analysis of physical and chemical properties. High bauxite clinker appearance was light gray and yellow and white and white, heavy and hard; bauxite homogeneous material appearance was uniform dark gray. Alumina From the physical and chemical properties of the test results can be seen: the chemical composition of the two raw materials is not very different, Al2O3 mass fraction of 80% or more, and according to the Al2O3 content and SiO2 content ratio can be seen, theoretically two raw materials are corundum Phase and mullite phase; Alumina the difference is that the density of the alumina homogenized material is larger than that of the bauxite clinker.

Phase analysis. From the XRD patterns of bauxite clinker and alumina homogenizer, Alumina it can be seen that the angular positions of the two kinds of bauxite raw materials are basically the same, and the main crystal phases are corundum facies. Stone phase, except that the peak of the same diffraction peak is slightly different.

Microstructure analysis. The researchers first observed the microstructure of the two raw materials at different magnifications. By observing the two kinds of bauxite raw materials at low magnification, Alumina it was found that the crystal distribution of high bauxite clinker was uneven, Alumina Into the crack; and alumina homogenization of the grain size and distribution are more uniform, but also see a small and uniform closed pores. Under the low magnification, the grain and pore size of the alumina homogenized material are larger than those of the bauxite clinker, and the stomata of the bauxite clinker can not be clearly seen at this fold.

Due to the presence of more homogeneous material (silicate glass phase) in the alumina homogenization material, the structural details are not clearly observed under orthogonal polarizations. Alumina Under the transmission electron microscope, the polarized light was photographed, Alumina and the unevenness of the high bauxite clinker was observed: the corundum crystal size and distribution were not uniform, and the content of the glass phase was less. Alumina From the transmission of light photos can also be seen in the homogenization of alumina homogenization: corundum crystal size and distribution is relatively uniform, the glass content of more and evenly distributed.

Application analysis. If the alumina homogenization material in the form of particles to do the raw materials, or by adding more isolated phase exists Si3N4, SiC and other non-oxide refractories, you can reduce the relative high temperature properties of the glass, so as to improve the bauxite The value of the use of materials. According to this idea, the researchers studied the application of bauxite clinker and alumina homogenizer in magnesium aluminum carbon materials.

Researchers, respectively, Alumina with bauxite clinker and alumina homogenized material for the alumina aggregate, in accordance with the above ideas made of two groups of magnesium aluminum carbon brick, and compared the two groups of brick at room temperature and high temperature strength difference. Alumina It was found that the high temperature performance of magnesium aluminum carbon brick made of alumina homogenized material was not weakened, but its high temperature flexural strength was higher than that of brick with high bauxite clinker. This confirms the value and prospect of homogenization in bauxite and non-oxide composites.


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