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This work was conducted to discover ways of processing high-paraffin oil residues using thermochemical processes to obtain binders. The principal purpose of such treatment of high-paraffinic residues is in the thermocatalytic process which consists of dehydroesterification via oxidation of paraffins which increase bitumen’s low-temperature stability (Fraass breaking point). Thus the n-alkanes, via our thermocatalytic process, can form several carbonyl compounds and oxidised compounds (such as alcohols, carboxylic acids, etc.). The thermocatalytic process of petroleum’s raw materials in our research carried out in two stages, including the catalytic process, as well as the thermal oxidation by air-blowing process. In this study, we used a biturox reactor. We evaluated the content of paraffin with GOST 33139 and low-field nuclear magnetic resonance (1H LF-NMR) relaxometry in high-paraffinic vacuum residues, and after our thermocatalytic process in the obtained product. Moreover, in order to ensure the reliability of results obtained through the processing of vacuum residues as well as the obtained product, various physicochemical methods were used. These investigation methods include SARA fractionation, Fourier-transform infrared spectroscopy, electron paramagnetic resonance (EPR), and VNII NP analysis. Furthermore, the colloidal structures were studied using the Gaestel and Asphaltene Index. The tests were carried out to determine the bitumen’s quality under the Russian interstate standard GOST 33133-2014 and the European standard EN 12591.

Gypsum crystals were formed from a saturated solution of produced water remaining in the horizontal section of the discharge pipe and cause undesired (side) man-made phenomenon as clogged pipe. However, for scientific purposes, this fact has become unique and revealed the typical defect centres, and enable us to study the effect of thermal and radiation effects on the crystal structure gypsum. Single crystals of gypsum at room temperature may gradually lose crystallization water. Its absence is compensated by the change of coordination number, calcium, and sulfur, which leads to the formation of point defects, which become paramagnetic during irradiation. It was found that the morphology of single crystals of gypsum corresponds to setting I2/a monoclinic system. The faces of the crystal are allocated on a well-developed cleavage plane (010) perpendicular to the axis b. Face, elongated along the [100] direction, was used to identify the orientation of the crystal in the resonator of electron paramagnetic resonance (EPR) spectrometer. In this paper, parameters of the spin Hamiltonian of paramagnetic centres and their models in a crystal of technogenic gypsum were presented. They are suitable for reliable ESR dating and reconstruction of the environment.

The electron spin resonance (ESR) spectra of SO 3 − and SO 2 − radical ions with a linewidth ΔH ≈ 2.7 G and SO 3 − (A 1) and SO 3 − (A 2) centers with superhyperfine splitting due to the interaction with protons in platelike gypsum single crystals under X-ray irradiation have been analyzed at 25°C. Dehydrated regions with a radius >4 A are revealed in gypsum. The ESR spectra of SO 3 − radical ions and atomic hydrogen with ΔH ≈ 0.3 G are found in the products of isothermal annealing of gypsum kept for 30 min after X-ray irradiation at 25°C. The dependences of the intensities of these spectra on the annealing temperature are studied in the range of 100–450°C. The temperature range of formation of α- and β-phase states of bassanite and γ-anhydrite are determined. The process of residual water redistribution between the channel systems of the α- and β-phase types of γ-CaSO4 in gypsum thermal derivatives is established.

The conditions for equivalent positions on the (hkl) face of growing crystal are derived using symmetry elements of the space group. It is shown by the example of the sp. gr. D2h16 that the conditions of equivalent position formation coincide with conditions of the reflection of diffracted beams by crystal. It is established that electron spin resonance (ESR) centers in barite, SO4− (I) and SO4− (II), with only two conjugate spectra with equal intensity out of four, and SO4− (III), with a different intensity of conjugate spectra KαM = 2, are localized into the growth pyramid of the (001) face with a [010] step. SO2−, SO3−,, and SO4− (IV) centers, having an identical intensity of the conjugate ESR spectra with KαM = 2, are localized into the growth pyramid of the (210) face with a growth step [001].

On the basis of the analysis of the electron spin resonance spectrum of the SO 3 − radical ion, it is established that the transformation of gypsum (CaSO4 · 2H2O) into bassanite (CaSO4 · 0.5H2O) with partial removal of water molecules occurs through the formation of an anhydrous metastable phase. This phenomenon, reflecting the processes of recrystallization of materials of this class, serves as the scientific basis for the production of binders from sulfate mineral associations.

The EPR spectra of Fe3+ impurity ions in NaZr2(PO4)3 single crystals at 300 K are investigated, and the spin Hamiltonian of these ions is determined. A comparative analysis of the spin-Hamiltonian and crystal-field tensors is performed using the maximum invariant component method. It is demonstrated that Fe3+ impurity ions substitute for Zr4+ ions with local compensator ions located in cavities of the B type. It is revealed that the invariant of the spin-Hamiltonian tensor B 4 and the crystal-field tensor V 4 44 depend substantially on the mutual arrangement of ions in the first and second coordination spheres. The corresponding dependences are analyzed.

An electron paramagnetic resonance (EPR) study of a synthetic single crystal of LiScGeO4 doped with Cr ions carried out earlier at the X- and Q-bands at 300, K has indicated additional weak lines. A detailed analysis of these EPR lines, which were tentatively attributed to the Fe3+ ions at two different mirror symmetry sites, is presented in this paper. The angular dependences in the three crystallographic planes were resolved by fitting the two distinct spectra denoted Fe3+(I) and Fe3+(II) with a spin Hamiltonian (S=5/2) of monoclinic symmetry. The rank-4 crystal field tensors at tetrahedral and octahedral sites were calculated with the point-charge model to determine the principal axis orientations of their cubic, tetragonal and trigonal components. A comparative analysis of the zero-field splitting tensors and the crystal field ones indicates that Fe3+(I) ions substitute for Sc3+ at octahedral sites and Fe3+(II) ions substitute for Ge4+ at tetrahedral sites with no significant distorition of the coordination polyhedra in the structure of LiScGeO4.

An electron paramagnetic resonance study of a synthetic single crystal of Cr-doped LiScGeO4 was carried out at the X- and Q-bands at 300 K and at the broad band (70-370 GHz) at 4.2 K. It was established that the EPR spectra with the magnetic multiplicity KM = 2 observed in all the frequency bands are due to the Cr3+ substituted for Sc3+ at the mirror symmetry octahedral site. The angular dependences of the two symmetry-related spectra of Cr3+ in the three crystallographic planes were fitted with the spin Hamiltonian (S = 3/2) of monoclinic symmetry. The zero-field splitting of the ground state energy levels was determined as 1.309(5) cm-1 which compares well with that for Cr3+ in forsterite and alexandrite crystals with similar olivine-like structure. Additional weak lines due to Mn2+ and Fe3+ at the mirror symmetry sites were also identified in the X- and Q-band spectra.

In single crystals of LiCaAlF6 and LiSrAlF6 doped with Fe3+ the trigonal EPR spectra with multiplicityK M = 1 were observed due to Fe3+ substituted for Al3+. The spin Hamiltonian parameters describing the fine structure and the superhyperfine structure were determined. It is argued that the tensorsB 2 andB 4 of the spin Hamiltonian for Fe3+ ions are essentially determined by the quadratic contributions of the crystal field at the substitution site. The signs and the relative values of the elements in the spin Hamiltonian tensorB 4 of rankL = 4 for Fe3+ are determined by the irreducible tensor product [V 4 ⊗V 4]2 of the crystal field tensorV 4 of rankL = 4 at the substitution sites. The ratio between the invariant sum of the spin Hamiltonian tensorB 4 for Fe3+ in oxygen octahedra [FeO6] and that in fluorine octahedra [FeF6] is directly proportional to the fourth power of the ratio between the effective charges of surrounding ions. The sign of the spin Hamiltonian parameterB 20 corresponds to the sign of the element [V 4 ⊗V 4]20 in the irreducible tensor product [V 4 ⊗V 4]2 of rankL = 2.

A single crystal of doped with was studied by EPR at room temperature and at using an X-band spectrometer. There are two magnetically equivalent spectra characterized by the main Stevens constants and . The spectra are described by a general spin Hamiltonian and all constants have been determined. The zero-field splitting of the energy levels is of the order of and EPR lines exist at very low fields, which are identified. The spectra are temperature dependent. This is interpreted as an anisotropic modification of the environment. The analysis of the pseudo-symmetry of the fourth order term of the spin Hamiltonian shows a strong modification of the local structure. The coordination polyhedra of are different from Zn and K polyhedra. The comparison with other results from the double sulphate family is made.

In single crystal colquiriite LiCaAlF6 doped with Gd3+ ions two EPR spectra of the Gd3+ ions with the Laue site-symmetry groups Ci and C3i were observed. The spectrum angular dependence for trigonal Gd3+ centre was investigated in detail and corresponding spin Hamiltonian parameters were fitted. From analysis of the spin Hamiltonian tensorsB 4 andB 6 it was established that Gd3+ with the Laue group C3i substitutes at Ca2+ site with the excess charge compensation by an ion located along the threefold axis from this site. The transformation formulas for a sixth-rank irreducible Hermitian tensor under coordinate rotation are tabulated in an explicit form. By using the EPR data for Gd3+ substituted in a variety of host crystals, the fourth-rank and sixth-rank tensors of Gd3+ spin Hamiltonians were tabulated and correlated with structures of the coordination polyhedra at substitution sites. The results suppose a predominance of quadratic crystal field contributions into the spin Hamiltonian tensorB 4 of Gd3+.

Dopant Fe3+ ions in tetrahedral and octahedral positions of Ge4+ in the crystal Li2Ge7O15 were studied using EPR. Fe3+ substitutes for Ge4+ with a local charge compensation. The octahedral site and the tetrahedral sites significantly differ by the value of the invariant sumS(B 4) of theB 4 tensor of the spin Hamiltonian of Fe3+. The irreducible tensor products {V 4 ⊗ V 4}4 and {V 4⊗V 4}2 theV 4 tensor of the crystal field calculated using the point-charge model for octahedral and tetrahedral complexes provide the predominant contribution of the crystal field to theB 4 andB 2 tensors of the spin Hamiltonian of Fe3+, respectively. A comparison of the fourth-rank tensorsB 4 of the spin Hamiltonian and {V 4⊗V 4}4 of the crystal field determined at 300 K with those determined at 77 K supports the conclusion that the phase transition is accompanied by combined rotation of the [GeO4] tetrahedra with the [Ge(1)O6] octahedron almost unaltered. The spectrum lines are narrow and the variety of point defects in the vicinity of the paramagnetic impurity ions Fe3+, Cr3+ and Cu2+ is not detected. These facts are inconsistent with the statistically distributed model for the Li(2) atom. In specific cases at 300 K, when the wings of the two spectrum lines of theM→M+1 and theM+2 →M+3 transitions of Fe3+ ions belonging to one system of translationally equivalent positions overlap an extra line appears in the center between these lines. It is suggested that this effect is due to the soft phonon mode above the phase transition temperature.

The expansion of the {B2} and {B4} tensors of the spin Hamiltonian (SH) for Mn2+ (6S-state) is performed in terms of the irreducible tensor products {VL1 ⊗VL2}2 and {VL1 ⊗VL2}4 of the crystal field (CF) tensors {VL1} and {VL2}. The EPR spectra of Mn2+ in the ZnSeO4·6H2O crystal are studied and the SH tensors {B2} and {B4} are calculated. The tensors {V4⊗V4}2 and {V4⊗V4}4 are computed using the point-charge model (PCM) of the [Zn(H2O)6] complex with the C2 symmetry and are compared with the SH tensors {B2} and {B4}, respectively. The correct signs of the elements and the pseudo-symmety axes of the tensors are obtained both for the {B2} tensor and {V4⊗V4}2 and for the {B4} tensor and {V4⊗V4}4. It is concluded that the irreducible tensor products {V4⊗V4}2 and {V4⊗V4}4 provide the predominant contribution respectively to the SH tensors {B2} and {B4} of Mn2+.

EPR data (i.e. the distribution of Mn2+ in carbonate rocks and of free radicals in terrigenous rocks) may be used to characterize sedimentary beds, especially if they are unfossilferous. The study of the distribution of Mn2+ that substitutes Mg2+ and Ca2+ in sedimentary dolomites suggests that the distribution is affected by their genesis.

The orientational dependences of the EPR spectra of Fe3+-doped LiCaAlF6 single crystals (space group P31c, Z=2), grown at the Laboratory of Magnetic Radio Spectroscopy at Kazan’ State University, have been investigated in detail. The spectrum is described by a trigonal spin Hamiltonian with the following parameters: B 20=40.072×10−4 cm−1, B 40=−5.799×10−4 cm−1, B 43=−4.281×10−4 cm−1, A s=24.33±1, A p=6.13±1, g ∥=g ⊥=2.00217±0.0003. A theoretical calculation of the hyperfine structure parameters shows that they are described quite well when allowance is made for the overlapping of the wave functions of the paramagnetic center and the ligands (F−).

Electron paramagnetic resonance study of a natural single crystal of natrolite was carried out at the frequency nu=36.772 GHz at room temperature. The angular dependence of the four symmetry-related spectra of Fe(3+) in the three crystallographic planes was fitted to a spin Hamiltonian (S=5/2) of symmetry C(i). The rank 4 crystal field tensors at tetrahedral sites were calculated using the point-charge model to determine the principal axes orientations of their cubic and trigonal components. The analysis of zero-field splitting tensors and comparison with crystal field ones suggests that Fe(3+) substitutes for Al(3+) with no significant distortion of the coordination tetrahedron in natrolite. Comparison of data for several natural and synthetic crystals reveals that the 4-rank zero-field splitting tensor invariants for Fe(3+) at the tetrahedral oxygen-coordinated sites are distinguishably smaller than those for Fe(3+) at octahedral sites. Such comparative analysis may help to determine the substitutional sites in other crystals.

The results of our research on travertine-like barite by electron paramagnetic resonance (EPR) are presented. The growth of these crystals was held in continuous motion of gas-water solutions at a constant radiation exposure of the nuclei 226 Ra, 232 Th and 40 K. The objective of this work was to identify the crystal-structure features of travertine-like barite associated with growth conditions under the influence of radiation exposure. Radiographic studies of barite samples have shown that the aggregates are virtually mono-mineral formations. It has a compressed unit cell with lower volume and higher density compared to the parameters of sedimentary barites. Only weak lines of the EPR spectrum of the ion-radical SO 2 − were fixed in the natural sample of barite. Therefore, laboratory experiments were carried out with X-ray ionization of samples, not only of the original rock, but also of samples exposed to thermal annealing. The EPR spectra of the following ion radicals: О − (g xx =2.0186; g yy =2.0121; g zz =2.0093), SO 2 − (g xx =2.0033; g yy =2.0126; g zz =2.0105) and two type - SO 3 − (I) (g xx =2.0034; g yy =2.0024; g zz =1.9995), SO 3 - (II) (g xx =2.0076; g yy =2.0022; g zz =1.9979) were detected after X-ray irradiation. The intensities of the lines of the observed EPR spectra of ion radicals change with annealing temperature. Paramagnetic centres form an integrated system with the structure of the crystal. Within the system, the transfer of electrons and holes is observed.