English English

Dudina S.N.

Candidate of Engineering Sciences (Ph.D.), Belgorod State National Research Universty

Structural and morphological characteristics of layered hydroaluminosilicates activated by solutions of alkali metal chlorides

, ,
 38-49 p.
Abstract
This study presents the results of a comparative investigation into the chemical and mineralogical compositions, as well as the structural-morphological characteristics of enriched and modified forms of clay, which contains layered hydroaluminosilicate – montmorillonite – as its main mineral phase. Impurity minerals in the clay raw material include kaolinite, low-temperature trigonal quartz, calcite, and illite, whose presence is confirmed by transmission electron microscopy and infrared Fourier spectrometry. Activation of the enriched rock was performed by treating it with solutions of alkali metal chlorides – lithium, potassium, and sodium chlorides. It is shown that the original form of the clay does not contain Na2O and Li2O oxides. However, through the salt treatment of the enriched hydroaluminosilicate rock, products with a content of lithium, sodium, and potassium oxides were obtained, amounting to 1.96%, 3.98%, and 6.28% by mass, respectively. It is established that the treatment with potassium chloride solution has the most significant influence on the structural-morphological characteristics of montmorillonite clay. Specifically, the sample treated with KCl solution exhibits an increased tendency towards particle aggregation and the formation of relatively large, spherical grains. It is also shown that the activated product mentioned above is almost entirely devoid of the mineral phase known as calcite. Meanwhile, the impact of LiCl and NaCl salt solutions on the enriched clay raw material hardly alters the microstructure of the resulting products.
PDF

FEATURES OF THE COMPOSITION AND STRUCTURAL AND MORPHOLOGICAL CHARACTERISTICS OF THE ACTIVATED HYDROALUMOSILICATE OF THE POLYANSKOYE DEPOSIT

, ,
 5-15 p.
Abstract
The results of a comparative study of the features of the material (chemical and mineralogical) composition and some surface characteristics of the enriched form of clay from the Polyana deposit subjected to activation by sulfuric acid treatment, as well as by exposure to IR- and UV-radiation are presented in this article. The initial clay material is accessible to polymineral rock with a predominance of montmorillonite hydroaluminosilicate in its composition (up to 75 wt %). There is IR and UV exposure to a significant change in the incoming composition of the clay, not observed. When an enriched form of clay is exposed to a solution of sulfuric acid, the proportion of cations (in particular calcium) in the exchange complex of clay decreases. In this case, a compensatory effect of protons on broken bonds localized on the surface of clay minerals is observed, which leads to a decrease in the absolute value of the electrokinetic potential on the surface of clay particles. Under IR- and UV-exposure of the clay material, a shift in the ξ-potential to the region of negative values is observed, which can be explained by the weakening of the bonds of exchange cations with the crystal lattice of montmorillonite, and, as a result, a change in the composition and structure of the interlayer medium. It was revealed that both UV and IR exposure to Polyanskaya clay leads to a decrease in the content of the proportion of freely bound water in the structure of montmorillonite hydroaluminosilicate. At the same time, treatment with UV-radiation significantly reduces the amount of OH-groups on the surface of the mineral due to the formation of siloxane bridges.
PDF

MINERALOGICAL COMPOSITION OF CLAYS OF THE «POLYANA» FIELD AS POTENTIAL SORPTION-ACTIVE MATERIALS OF INORGANIC ORIGIN

, ,
 67-76 p.
Abstract
This work presents the results of a study of the phase (mineralogical) composition of clay from the Polyana field, Shebekinsky district, Belgorod region. To study the morphological and structural features of the mineral components that make up the specified clay, a set of methods of scanning and transmission microscopy, electron microdiffraction and energy dispersive analysis were used. Electron microscopic examination of Polyanskaya clay showed that it is composed of such minerals as: calcium and magnesium-iron form of montmorillonite, muscovite, low-temperature trigonal quartz, illite and ruthyl. More often than others, the preparations contain particles identified as montmorillonite, differing in structure without shaped edges and having a layered structure (layer thickness of about 1 nm). Particles of this mineral show a high tendency to aggregation, but at the same time they are quite easily split along the cleavage plane during dispersion, and therefore have a developed specific surface area, which determines good sorption characteristics.
PDF