Application of Evolved Gas Analysis Technique for Speciation of Minor Minerals in Clays

Eulalia Zumaquero Silvero,María Jesús Ventura Vaquer,Eva María Díaz-Canales,Jessica Gilabert Albiol,María Pilar Gómez-Tena

doi:10.3390/min10090824

Eulalia Zumaquero Silvero, María Jesús Ventura Vaquer + Show 3 more

Open Access

https://doi.org/10.3390/min10090824

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Journal: Minerals	Publication Date: Sep 18, 2020
Citations: 6	License type: CC BY 4.0

Affiliation: Instituto de Tecnología Cerámica, Jaume I University

Abstract

Mineralogical characterization of clays used in manufacturing of traditional ceramic products is critical for guarantee the quality of the final product, but also for assessing the environmental impact of the industrial process in terms of atmospheric emissions. In fact, the presence of impurities even in low-level concentrations can have a big impact. So, it is very important to carry out an accurate mineral quantification of those minerals which are related to carbon dioxide and acid emissions (hydrogen fluoride, hydrogen chloride or sulfur dioxide). The development of hyphenated techniques coupling thermal analysis equipment with mass spectrometry and Fourier-transform infrared spectroscopy provides more valuable information and lower limit quantification than other primary techniques, such as X-ray diffraction or infrared spectroscopy. The main objective of this work is to develop an analytical procedure using evolved gas analysis to identify and quantify minerals such as chlorides, sulfides, carbonaceous materials and minor clay minerals. In addition to this, the study includes the analysis of acid emissions during the ceramic firing treatment even if they are present at low quantitative levels. This methodology was applied to reference materials so that it allows the identification of sulfur, chlorine, fluorine and carbonaceous compounds in concentrations lower than 1%.

Highlights

The emission of acid compounds into the atmosphere in the ceramic tile manufacture has become an important problem in the ceramic sector
X-ray fluorescence (WD-XRF), ion chromatography, infrared detection, inductively coupled plasma optical emission spectrometry (ICP-OES) . . . but they present some limitations as the presence of interferences in a complex clayey matrix when using WD-XRF, the detection limit, the difficulty of the speciation or limitations in the determination of some analytes in the case of ICP-OES technique
The emission of carbon dioxide during the thermal treatment of raw materials can be derived from different sources, either from the decomposition of carbonates such as calcite, dolomite or magnesite or compounds from the thermal degradation of small percentages of organic matter found in clays

Summary

Introduction

The emission of acid compounds into the atmosphere in the ceramic tile manufacture has become an important problem in the ceramic sector. These acid compounds (chlorides, fluorides, sulfides and carbon compounds) are caused by the presence of impurities in the raw materials and can be identified during the tile firing stage where the processed materials reach high temperatures releasing HF, HCl, SOX and CO2. In the case of fluorine emissions, it is crucial to obtain a better understanding of the nature of fluorine within the raw materials and how fluorine evolves during the firing process.

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