Determination of Alumina

You can get Aluminum contents of it determined using ESCA or SIMS technique. You can also estimate Al2O3 using XRF. Other techniques are AAS and chemical analysis.

The more reliable and cost/effective method for quantitative (volumetric) determination of alumina (and also its polymorphs, alpha, gamma etc.) is actually X-ray diffraction. XRF will not give you a good quantification on such a complex matrix and also cannot distinguish between the Aluminum in the alumina and elsewhere as impurity (XRF identify the elements but not which phase they belong to). XRD identify and quantify the phases directly instead. ESCA and SIMS may be a little difficult to found, apply and not so easy for quantification..... Raman instead can be more usable in this case due to the fact you are looking for alumina. Luca Lutterotti Luca.Lutterotti@ing.unitn.it

Fluorescent X-ray analysis and emission spectrometric analysis (quantovac) were compared each other for the determination of Si, Mn, P, S, Cu, Cr, and Ti in pig iron and a consideration was given to the effects of the metallic structure of a sample on precision and accuracy of the analytical results. The instruments used for this study were X-ray quantometer VXQ-120, two simultixes and two vacuum quantorecorders. A pair of samples were taken into both steel and sand moulds from a spoon of metal. Some of elements the calibration standards of which were required were added into a spoon for several charges of all 50 samples. For quantovac analysis, there was little difference in calibration curves between samples of the different moulds, while for X-ray analysis the calibration curves of Si, P, S, and Ti showed some differences which made greater as the atomic number decreased. In the samples of less than 0.40% of Si and/or more than 0.30% of Cr taken into sand mould, whose structures showed white or mottled pig iron structure, analytical values of P and S gave big errors. Precision was in the same level for X-ray and quantovac analyses for heavy elements, but the former was superior to the latter for P and S by factor of 3 to 5. Accuracy of X-ray system was comparable to that of quantovac system. It was concluded as the results of this study that fluorescent X-ray analysis was preferable to quantovac system for a production control analysis of pig iron from overall view points.First Read and Digest this. Things will be a lot clearer later.

XRD is for crystalline phase and as suggested by you is a good idea. What I have suggested is elemental analysis and not molecule and molecular phase analysis. If Alumina is transparent then IR spectra and Photo-acoustics spectra will give some idea of molecular contents but XRD is a much better idea and cheap way out.

I think this suggestion was well analyzed one. Good.

If you are in the serious business of Quantitative analysis of Oxides in Ceramic Materials, you need to use the following 3 books

1. DIRECT DETERMINATION OF SODIUM OXIDE IN FELDSPAR E. W. Koenig Abstract

A method for the direct determination of sodium oxide in feldspars is described. Data derived from an investigation conducted to determine the optimum conditions for the accurate estimation of this alkali metal by the prescribed procedure are tabul...

Journal of the American Ceramic Society, Volume 22, Issue 1-12: 24-31. doi: 10.1111/j.1151-2916.1939.tb19422.x

2. THE SEMIDIRECT DETERMINATION OF POTASSIUM OXIDE IN FELDSPARS E. W. Koenig Abstract

A method for the evaluation of potassium oxide in feldspars, without the necessity of first removing the constituents which usually interfere with this determination, is described. The procedure is based upon a decomposition with HF-HClO₄, followed...

Journal of the American Ceramic Society, Volume 22, Issue 1-12: 164-168. doi: 10.1111/j.1151-2916.1939.tb19443.x

3. CALCULATION OF MINERALOGICAL COMPOSITION OF FELDSPAR BY CHEMICAL ANALYSIS* E. W. KOENIG Abstract

Formulas are given for the determination of the percentage amounts of microcline, albite, anorthite, kaolinite, muscovite, and free quartz in feldspars.

Journal of the American Ceramic Society, Volume 25, Issue 14: 420-422. doi: 10.1111/j.1151-2916.1942.tb14343.x

Any lab with an X-Ray Diffractometer using Rietveld techniques (structural analysis software using space group data) should be able to provide quantitative analysis of the components in the mixture you describe. I would think this type of analysis would be more accurate than a volumetric test.

Bill Morrow

XRD can give good relative information for components with known signatures. I am not sure how accurate is absolute information as that will require uniformity, and quantitative analysis and some kind of instrument calibration. All you get is those peaks for each material type and relating that to volume or weight may require some proper way. If you consider some significant peak as 100% then all other peaks are relative to it.

Can any one point out the way XRD is used for quantitative analysis? I think it will require calibration with some standards.

Not necessarily, calibration was needed using old quantification methods. Now with the Rietveld method is no more necessary (look at the response of Bill also). I have direct experience with both as I made the alumina analysis quite often and I wrote a couple of Rietveld software for quantitative analysis. If you look for the Rietveld program Maud on google in the tutorial section there is one on quantitative analysis with a diffraction spectrum of corundum (alpha alumina) + something else. You can see how it works and try yourself dowloading the program. Best regards, Luca Lutterotti

Hmm, since it doesn't occur as alumina but rather as aluminum and oxygen bound in the feldspar mineral crystal matrix. To estimate the alumina content, you need to determine the molar aluminum content then recalculate the mass as pure alumina then use pure alumina density to get a volume. Accuracy is key here, and some methods such as AA spec will require destruction of the sample. if you are just estimating, the range for aluminum in feldspar can be found in a geotchemistry book.