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Vol. 9 Issue 1

Archives Journal Chemical Bulletin Vol. 9 Issue 1

Comparison of the effectiveness of rice husk ash for solid phase synthesis of wollastonite and diopside

https://doi.org/10.58224/2619-0575-2026-9-1-1
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Abstract
Objectives: This study aims to evaluate the prospects of using rice husk ash for the production of calcium-magnesium silicates and to identify differences in the solid-phase synthesis processes of wollastonite and diopside based on rice husk ash.
Methods. X-ray quantitative phase analysis was used to analyse the obtained samples of synthetic wollastonite and diopside. The porosity of calcium-magnesium silicates was evaluated by a static volumetric method using low-temperature nitrogen adsorption. The elemental composition of the samples was determined using an Oxford INCA X-max 80 energy dispersive detector, and electron microscopic analysis was performed using a Jeol JSM7001F scanning microscope.
Results. Experimental data comparing the properties of synthesized diopside and wollastonite showed that wollastonite is characterized by high porosity and average particle size compared to diopside due to the lower temperature of solid-phase synthesis. The structure of synthetic wollastonite is distinguished by the presence of large irregularly shaped inclusions with a small amount of needle-like particles, while synthesized diopside does not contain needle-like particles, and the inclusions are characterized by smaller size and uniform distribution throughout the volume.
Conclusions. When obtaining calcium-magnesium silicates by solid-phase synthesis based on rice husk ash, the yield of the final product synthetic diopside is significantly higher than that of synthetic wollastonite. The process of synthesizing diopside is less labor-intensive and time-consuming, but more energy-intensive due to the higher synthesis temperature of diopside.
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Influence of technological parameters of potassium chloride production on corrosion-abrasive wear of double-layer steel 1.4462

https://doi.org/10.58224/2619-0575-2026-9-1-2
Abstract
The paper presents the results of laboratory studies of corrosion-abrasive wear of a screw dissolver made of duplex steel 1.4462 in an environment simulating potassium chloride production conditions (4RU of JSC "Belaruskali"). The influence of mechanical impurities (abrasive), temperature (105 °C), pH (4-8), artificial air supply, and incomplete immersion mode was experimentally studied. It has been established that the presence of abrasive increases the mass loss rate by 10 times (up to 0,015 g/day) compared to purely chemical corrosion [2]. The most intense pitting damage is observed in areas with oxygen access. An alkaline environment (pH= 8) promotes the formation of protective deposits, while an acidic one (pH= 4–7) intensifies corrosion [7]. Equipment operation with incomplete immersion of the agitator increases the corrosion rate by 40 % [2, 9]. Duplex steel 1.4462 shows high resistance to chemical corrosion, but its service life is sharply reduced under the combined influence of abrasive and non-standard operating conditions [2, 20]. Practical recommendations for extending equipment service life are given.
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Mathematical modeling of a solid oxide fuel cell

https://doi.org/10.58224/2619-0575-2026-9-1-3
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Abstract
Objectives: development of a mathematical model to describe the phenomena occurring in a medium-temperature solid oxide fuel cell. Solving the model equations requires finding a number of kinetic parameters, including the rate constants of electrochemical reactions.
Methods. To determine the viscosity of polymer solutions, their molecular weight and to study the adsorption of k-carrageenan on CX, the method of capillary viscometry was used. The assessment of the stability of the zones over time was carried out photometrically.
Results. The mathematical model is based on a system of partial differential equations and includes material and heat balance equations, as well as charge balance relationships. An algorithm for numerically solving the mathematical model equations and a corresponding software module for calculating the equations implemented in the Python programming language have been developed.
Conclusions. The developed mathematical model adequately describes the processes occurring at the electrodes of a medium-temperature fuel cell. The optimal fuel-to-oxidizer ratio was determined to be 1:10.
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Phase formation in triple salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) and some properties of triple molybdates Rb5A0.5R1.5(MoO4)6

https://doi.org/10.58224/2619-0575-2026-9-1-4
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Abstract
As a result of studying the possibility of phase formation in triple salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A – divalent elements; R = Zr, Hf) phases of the composition Rb5A0.5R1.5(MoO4)6, were obtained, which are assigned to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and represent a series of isostructural substances crystallizing in trigonal syngony (sp.gr. R3c или R3) [1, 2]. Crystallographic and thermal characteristics of the synthesized compounds were determined.
Methods. The subsolidus structure of the ternary salt systems Rb2MoО4–АMoO4–R(MoO4)2 was established using the “intersecting cuts” method. polycrystalline samples The powder samples compounds Rb5А0.5R1.5(MoO4)6 (A = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained by solid-phase synthesis at 500–530°C.
Results. The subsolidus structure of the ternary salt systems Rb2MoO4–AMoO4–Zr(MoO4)2 (A = Mn, Pb,), Rb2MoO4–AMoO4–R(MoO4)2 (A = Zn, Cd, R = Zr, Hf) was established. The Rb5A0.5R1.5(MoO4)6 (А = Mg, Ca, Mn, Co, Ni, Zn, Sr, Cd, Ba, Pb; R = Zr, Hf) were obtained in powder form, their crystallographic and thermal characteristics were determined. IR and Raman spectra were recorded and analyzed for the compounds Rb5A0.5Zr1.5(MoO4)6 (A = Ni, Со, Mg, Zn), Rb5Ba0.5Zr1.5(MoO4)6.
Conclusions. Phase formation in ternary salt systems Rb2MoO4–AMoO4–R(MoO4)2 (A = Mg, Mn, Zn, Ni, Co, Cd, Ca, Pb, Sr, Ba; R = Zr, Hf) was studied and a subsolidus structure was established for six of them. Compounds Rb5A0.5R1.5(MoO4)6 were obtained by solid-phase synthesis at 500–530°C and belong to a large family of ternary molybdates with the general formula M5A0.5R1.5(MoO4)6 (M – single valent element, A – divalent element, R = Zr, Hf) and crystallize in two structural types: molybdates with large divalent metals (A = Ca, Sr, Ba, Pb) – in the structural type Tl5Pb0.5Hf1.5(MoO4)6 (пр.гр. R3, [2]), molybdates with divalent metals whose radius is less than 1Ǻ (A = Mg, Mn, Zn, Ni, Co, Cd) – in the structural type K5Mg0.5Zr1.5(MoO4)6 (пр.гр. R3c, [1]).
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