Naslov
Mössbauer study of bentonites from Croatia and neighbouring countries

Autori
Tibljaš, Darko ; Hanžel, Darko ; Gverić, Zvonka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Euroclay 2019 Book of abstracts / - Pariz, 2019, 598-598

Skup
International Conference on Clay Science and Technology (EUROCLAY 2019)

Mjesto i datum
Pariz, Francuska, 01.07.2019. - 05.07.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
smectite, Mössbauer spectroscopy

Sažetak
There are several known deposits of bentonites in Croatia. With the advancement of analytical methods and new findings about smectite characterisation in recent years, a demand for a full characterisation of known bentonite deposits occurred. Recently, thirteen samples of bentonites were studied by X-ray diffraction, FTIR spectroscopy, thermal (DTA and TG/DTG) and chemical methods (ICP/AES and ICP/MS). Most of the samples are from Croatia (Poljanska Luka, Šaša – Bednja, Draga – Gornja Jelenska, Lončarski Vis, Sjeničak, Paripovac, Divoselo and Bunarić – Maovice), but for comparison, samples from Bosnia and Herzegovina (Sokolac and Greda – Šipovo), Slovenia (Zaloška Gorica), and Serbia (Vranjska Banja) were also analysed. One of the criteria for smectite classification (Emmerich et al., 2009) is their Fe-content. Therefore, in order to fully characterise investigated materials, Mössbauer spectra of < 2µm fractions were recorded. According to the chemical analyses most of the analysed bentonites are Fe-poor (they contain < 0.30 mol Fe/f.u.). Samples Divoselo 1 and Šipovo - Sokolac contain 0.30 mol Fe/f.u., while the sample from Bednja is ferrian (0.38 mol Fe/f.u.). Mössbauer spectra recorded at room temperature differ significantly. Some of them, including the one of Bunarić sample with the lowest Fe content can be fitted with single or dominant doublet characteristic for Fe(III) in octahedral coordination. Others, like the one of Bednja sample with the highest Fe content have to be fitted with up to four doublets: two for Fe(III) in octahedral coordination, one attributed to Fe(II) in octahedral coordination and one for Fe(III) in tetrahedral coordination. There is no clear evidence of the presence of magnetically ordered phase, which indicates that most of the Fe present in the fine fraction of investigated smectites is incorporated in smectite structure.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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