Remarks on different methods for analyzing trona and soda samples

Year 1986, Volume: 105-106 Issue: 105-106, 66 - 77, 01.10.1986

Gülay Ataman Süheyla Tuncer Nurgün Güngör

Abstract

Trona is one of the natural forms of sodium carbonate minerals. It is well known as «sesque carbonate», «urao» or «trona» in the chemical literature, and the chemical formula of the compound is [Na₂CO₃ .NaHCO₃ .2H₂O]. The aim of this work is to adopt the standard methods for the analysis of trona samples, considering the interferences arising from silicates and other minerals found together with trona samples. In order to reduce the experimental errors, the analyses used for the determination of trona samples have been revised. The experimental results using potentiometric titration, AgNO₃ external indicator and BaCl₂ titration methods have been compared to theoretical results using statistical evaluations. 95% confidence level, which is commonly used by analytical chemists, was employed as the basis of evaluation, R values, Student's t calculated at 95% confidence level of 7 trona samples from Beypazarı, Student's t tabulated for the percentages of Na₂CO₃ , were found to be 0.008 in BaCl₂ method, 3.25 for AgNO₃ external indicator method and 3.26 for potentiometric method; for the percentages of NaHCO₃ the same values are 0.59 for BaCl2 method, 2.83 for AgNO₃ external indicator method and 3.59 for potentiometric method. Systematic error is indicated when R> 1. In addition to quantitative analysis of trona samples, qualitative XRD analyses have been routinely performed for each sample and the results were found to be in good agreement.

Keywords

-

References

• Frint, W.R., 1971, Processing of Wyoming trona: Contributions to Geology, 10, 43.
• Stanley J. Lefond (ed.), 1980, 4th Edition, Industrial Minerals and Rocks, Port City Baltimore, 1061-1080.
• Sungun, K.D., 1983, Dünyada ve Türkiye'de soda problemleri: Kimya Sanayii, Haziran-Eylül, 99-123.
• Skoog, D.A. and West, D.M., 1969, Fundamentals of Analytical Chemistry: 2nd Edition. Holt Rinehart Winston Inc.
• Food Chemical Codex III, Monographs, 299, 3rd Edition, 1981.
• Annual Book of ASTM Standards, Part 30, 1980 Easton, Md Inc., USA.
• Laitinen, H.A., 1960; Chemical Analysis: Mc Graw Hill Book Co., Toronto, 611.