Physicochemical and radiological characterization of kaolin and its polymerization products

M Ivanović,N Bundaleski,I Vukanac,S Nenadović,B Todorović,M Nenadović,Lj Kljajević

doi:10.3989/mc.2018.00517

M Ivanović, N Bundaleski + Show 5 more

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https://doi.org/10.3989/mc.2018.00517

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Abstract

The aim of this study was determination of physical-chemical and radiological characteristics of kaolin and products of alkali-activated thermally treated kaolin (geopolymer). Also, the objective of presented research was to investigate the possibility of kaolin application as a pigment or as a raw material for obtaining geopolymer materials as a relatively new ones in a building material industry. Physicochemical characterization of one set of samples was conducted using X-ray diffraction (XRD), Fourier transform infra - red (FTIR) and X-ray photoelectron spectroscopy (XPS). Activity concentration of naturally occurring radionuclides in kaolin, metakaolin and geopolymer were determined. The absorbed dose rate (D) and the annual effective dose rate (EDR), calculated in accordance with the UNSCEAR 2000 report, are also presented in this paper. Kaolin was heat-treated on 750oC and specific activity of natural radionuclide in metakaolin increased up to 1.6, while measured specific activities in geopolymer were the lowest.

Highlights

EnvelopeAl 2p and Si 2p lines taken from the GP sample consist of a single and two contributions, respectively
According to the identified X-ray diffraction (XRD) patterns, the mineral phases identified in the as-received kaolin sample are kaolinite, muscovite and quartz (Fig. 1a)
XRD, Fourier transform infra - red (FTIR), X-ray photoelectron spectroscopy (XPS) analysis of the investigated samples showed mineralogical composition, new chemical bondings, as well as the present phase of the metakaolin that was used as a monomer in the polymerization process

Summary

Introduction

Al 2p and Si 2p lines taken from the GP sample consist of a single and two contributions, respectively. The position of this line strongly depends on the amount of sialate bonds in the geopolymer. In the case of pure siloxo bonds, Si 2p3/2 line is situated at 103.8 eV [42]. After subtracting the amount of silicon bound in quartz, the ratio between the Si and Al concentrations in geopolymer was evaluated to be 1.47. This ratio clearly suggests that the geopolymer sample consists of the roughly equal amounts of siloxo (Si-O-Si) and sialate (Si-O-Al) bonds.

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