INFLUENCE OF PRESSURE ON THE STRUCTURE OF KAOLINITE IN FIRE-CLAYS OF THE NIZHNE-UVELSKOGO DEPOSIT BY IR SPECTROSCOPY

• Main Authors: Olga S. Siteva, Natalia A. Medvedeva, Valeriy V. Seredin, Dmitriy V. Ivanov, Karine A. Alvanian
• Format: Article
• Language: Russian
• Published: Tomsk Polytechnic University 2020-06-01
• Series: Известия Томского политехнического университета: Инжиниринг георесурсов
• Subjects: fire-clay; kaolinite; deposit; modification; infrared spectroscopy; the degree of perfection of the structure
• Online Access: http://izvestiya.tpu.ru/archive/article/view/2690/2255
• ISSN: 2500-1019; 2413-1830

The research is relevant due to the need to study the structure of kaolin clays in relation to their wide industrial application. Physical and physico-chemical properties of clays change under various technogenic impacts on them. The change is caused by crystalline structure transformation. The main aim of the research is to study the effect of pressure on the structure of kaolinite. The object of the research is the kaolin clay of the Nizhne-Uvelskoe deposit of the Chelyabinsk region. The method of the research is the infrared spectroscopy. Infrared spectra were recorded on an IR Fourier-spectrometer in the range 400...3800 cm–1. IR spectrum was processed using Fspec software. The results of experimental studies showed that the enriched kaolin clay of the Nizhne-Uvelskoe deposit of the Chelyabinsk region, which was not exposed to pressure, is characterized by a partially ordered (defective) structure. Under the influence of pressures from 10 to 650 MPa, the clay is characterized by a partially ordered structure, at pressures from 700 to 800 MPa – a poorly ordered and disordered structure. Pressure treatment of kaolin increases the defectiveness of the structure at the packet level. The bonds between Al-OH, Si-O-Al, inner and inner-surface hydroxyls are destroyed, which leads to the displacement of Al from the octahedral and Si from tetrahedral sheets and the formation of «hole» energy centers in the kaolinite crystal lattice. Moreover, the effect of pressure up to 150 MPa on formation of defects in kaolinite is higher than at pressures from 150 to 800 MPa. In addition, during the processing of kaolin by pressure, structural defects are formed at the inter packet level due to sliding, rotation and rolling of structural packets between themselves.