Acta Metallurgica Slovaca

THEORETICAL AND EXPERIMENTAL MODELING OF THE PROCESS OF MELTING COMPLEX ALLOYED STEELS (Fe-Si-Al-Mn)

Bauyrzhan Kelamanov — 2024-06-18

In the practice of complex theoretical research of multicomponent systems, the so-called thermodynamic-diagram method of analysis is known, which significantly simplifies the study of phase transformations in multicomponent systems by dividing them into thermodynamically stable elementary partial subsystems of equal dimensionality as the main ones. Thermodynamic-diagram analysis combines the thermodynamic assessment of chemical interactions between components in the studied system with a geometric diagram. Such a combination, as studies of the physicochemical principles of refractories and ferroalloys production have shown, proves to be productive in interpreting chemical interactions in complex systems.

Thermodynamic Diagram Analysis and Smelting of Complex Fe-Cr-Mn-Si Ferroalloy

Serik Gabdullin — 2024-06-18

A state diagram of the Cr-Mn-Si-Fe metallic system, which simulates the compositions of complex chromium-manganese-silicon-containing ferroalloy (Fe-Cr-Mn-Si), has been constructed using thermodynamic-diagram analysis. Theoretical investigations have determined that the system comprises eight elementary tetrahedra. The sum of the relative volumes of the elementary tetrahedra equals one (1.00000), confirming the accuracy of the tetrahedration conducted. Analytical expressions for each tetrahedron have been derived. Calculations have determined the tetrahedron characterizing the phase composition of the ferroalloy. This tetrahedron is identified as the most voluminous phase triangle in the Cr-Mn-Si-Fe metallic system, implying that its significant volume facilitates the smelting process of chromium-manganese-silicon-containing ferroalloy, i.e., there is the possibility of freely regulating the charge compositions to achieve the required alloy grade. Based on the obtained results, an experimental smelting of the Fe-Cr-Mn-Si ferroalloy was conducted using a charge composed of chromium ore, low-grade manganese ore, and coke, resulting in a sample with the following composition, %: 44.07 Cr, 13.97 Fe, 12.48 Mn, 9.48 Si, 4.45 C. The microstructure comprises a complex silicide (Cr, Fe, Mn)₃Si and Cr₃C₂ carbides.

STUDIES ON EXTRACTION OF COPPER FROM SULFURIC ACID SOLUTION AFTER THERMOCHEMICAL ENRICHMENT OF ROUGH CONCENTRATE

Lyutsiya Karimova — 2024-06-18

One of the processes of complete and complex extraction of valuable components is the desiliconization of final tailings to increase the content of concentrate and obtain marketable products in the form of white soot and copper cathode. This study aimed to investigate the possibility of further extraction of copper from the sulfuric acid solution obtained after the thermochemical enrichment of rough copper concentrate on a temperature range of 300-500°C. Acorga M5774 extractant and Elixore 205 diluent served to extract copper from the pregnant solution containing 9.59 g/l copper and 24.6 g/l iron. The study of the extractant performance and parameters involved plotting the isotherms of extraction and re-extraction curves. The result shows thermochemical enrichment of the rough concentrate using alkali and subsequent leaching with further copper extraction. The concentrate water leaching yielded 88.0% silicon recovery and 96.15% copper recovery. The copper recovery was 97.9%, with an organic-to-water phase ratio of 1.2. From the dependence of iron transfer on the copper saturation of the organic phase, it follows that if the latter is low, the rest of the extractant will absorb iron, so some excess copper content is required.

NOVEL INSIGHTS INTO PHASE FORMATION AND ELECTRICAL RESISTIVITY OF FeSe ALLOY PREPARED BY POWDER METALLURGY METHOD

Sigit Dwi Yudanto — 2024-06-18

This study prepared the FeSe alloy using a powder metallurgy route. The Fe and Se powders were weighed at an atomic ratio of Fe:Se = 1.025:1 and milled for 5 hours. A simultaneous thermal analysis (STA) was performed to observe the behavior of the milled powder during thermal changes. After packing the milled powder in a stainless-steel tube, it was compacted. Investigation was performed to observe how the tetragonal FeSe phase forms at sintering temperatures of 718 K, 818 K, and 918 K. At a sintering temperature of 718 K, the tetragonal FeSe phase was formed, as determined by our quantitative analysis of XRD. The highest tetragonal FeSe phase fraction of 68.46 wt.% was obtained at a temperature of 918 K. The lattice constants of the tetragonal FeSe for the best sample were a = 0.3773 nm and c = 0.5520 nm. The resistivity test demonstrated that all samples have a conductor phenomenon exceeding 16 K, with a maximum Tc-onset value of 15.11 K.

THERMODYNAMIC ANALYSIS OF PHASE DIAGRAMS BASED ON THE CONCEPT OF THE BJERRUM–GUGGENHEIM OSMOTIC COEFFICIENT

Sailaubai Baisanov — 2024-06-18

The aim of this study is to theoretically confirm or refute the high degree of lead and zinc volatilisation from the Shalkiya deposit (polymetallic refractory ores) by means of analysing the phase diagrams and the behaviour of the osmotic coefficient according to the Bjerrum-Guggenheim equation along the liquidus line for binary systems based on calcium. From the plots depicting the dependence of the Bjerrum-Guggenheim osmotic coefficient on activity, one can infer the structure of the melt (positive <1 or negative >1). That is, if the values of the Bjerrum-Guggenheim osmotic coefficient in a binary system indicate a positive character of interaction between the components, it implies interaction between like atoms in the melt, whereas negative values indicate interaction between unlike atoms, suggesting the formation of complex, high-temperature compounds, which would be undesirable in our case. The question related to the formation of complex high-temperature chemical compounds with impurity elements such as zinc and lead in the Fe-Si-Al-Ca-Mg-Zn-Pb system remains unresolved.

THE SIMULATION OF THE ANISOTROPY OF ALUMINUM ALLOY SHEETS BY DEEP DRAWING: A CRUCIAL STUDY FOR THE AUTOMOTIVE AND MATERIALS ENGINEERING INDUSTRIES

Emil Spišák — 2024-06-18

Recently, the automotive industry has shown an increasing interest in utilizing thin aluminum alloy sheets to reduce the weight of various car components. The occurrence of uneven cup heights in deep drawing processes is called earing. This issue arises due to the planar anisotropy of sheets, a consequence of crystallographic texture. Therefore, this study involves a meticulously conducted cylindrical cupping test. For the experimental research, four different aluminum alloys were used, each with distinct mechanical and plastic properties. The experimental results of the drawing process were compared with the simulation results using the Simufact Forming software. Different numbers of elements were selected for experimental material with a 1 mm thickness to further compare the simulation results with experiments. In a separate simulation in the Simufact Forming software, the effect of the number of elements on the earing height and computing time was evaluated. The results obtained with five different solvers were compared within Simufact Forming. The results showed significant differences in computing times for the different types of solvers.

STUDY OF THE EFFECT OF FLUXING MATERIALS ON THE DEPOSITION OF METAL BEADS FROM HIGH CARBON FERROCHROME SLAG

Aibar Myrzagaliyev — 2024-06-18

The study of the effect of the properties of high-carbon ferrochrome slags on the creation of favorable conditions for the deposition of metal beads with the introduction of the following fluxing additives in an amount of 3-10%: slag produced by refined ferrochrome (stale and stabilized), cryolite, fluorite, feldspar, colemanite, fused borate ore, aluminum slag of aluminum production. The influence of the type and quantity of fluxing materials on the viscosity and crystallization temperature of high-carbon ferrochrome slags has been studied. It is noted that the use of all types of fluxing materials under study leads to a decrease in the crystallization temperatures of the processed slag. It can be seen from the results of metallographic and phase analyses that the best values for the degree of coagulation and deposition of metal crowns were achieved with the introduction of aluminum slag, colemanite and borate ore.