scholarly journals Strusky z redukční tavby pelosideritové železné rudy realizované na hradě Buchlově (jv. Chřiby) v roce 2019: extrémní variabilita fázového složení a chemismu jednotlivých fází

2021 ◽  
Vol 29 (1) ◽  
pp. 59-76
Author(s):  
Zdeněk Dolníček ◽  
Ladislav Kandrnál ◽  
Jana Ulmanová ◽  
Ester Vratislavská ◽  
Pavel Hojač
Keyword(s):  
Phase Composition ◽  
Chemical Composition ◽  
Metallic Iron ◽  
Glass Phase ◽  
Shaft Furnace ◽  
Early Period ◽  
Crystalline Phases ◽  
Direct Production ◽  
Natural Systems ◽  
Slag Melt

During experimental smelting of iron in a replica of historical shaft furnace, which was held at the Buchlov Castle in 2019, charcoal and fresh pelosiderite iron ore from the locality Moravany near Kyjov were used. The obtained furnace slag is practically completely formed by glass phase; only rare small domains contain also crystalline phases, whose occurrence is very irregular. A detailed study of chemical composition showed extreme heterogeneity in composition of glass and most crystalline phases. The glass phase contains variable, but often high amounts of Mn, Ca, Mg and sometimes P and/or K. The composition of olivine ranges widely among fayalite, dicalciumsilicate and tephroite (Fa1-91 Fo3-28Te2-45DCS1-52), as well as those of calcic pyroxene (Wo37-60Tsch1-13Ka8-22Fs4-30En14-36). Feldspars showed compositions between orthoclase and anorthite (Or2-82An9-91Ab5-19Cn0-2Slw0-2), which are unknown from natural systems. Minor components include wüstite, melilite (åkermanite with 1 - 6 mol. % gehlenite), leucite, kalsilite, locally also apatite and an unnamed phase with composition close to Ca2Al2Si3O11. The produced metallic iron is also compositionally heterogeneous and rich in phosphorus. The phase composition of slag differs significantly from those of typical iron slags. The reason can be seen in anomalous chemical composition of used ore, in too high temperatures during smelting (phase relations in metallic iron suggest temperatures around 1500 °C) in combination with rapid cooling of the furnace content after finishing of smelting, and probably also higher viscosity of slag melt. Both phase composition of slag as well as chemical composition of individual slag phases and metallic iron are significantly different from those of local historical artefacts from the period of usage of technology of direct production of iron. These findings do not support the idea that local pelosiderite iron ores were used for production of iron already during this early period.

scholarly journals Strusky a železo z experimentální tavby železa realizované na hradě Buchlově (jv. Chřiby) v roce 2018

2020 ◽  
Vol 28 (1) ◽  
pp. 58-68
Author(s):  
Zdeněk Dolníček ◽  
Ladislav Kandrnál ◽  
Jana Ulmanová ◽  
Ester Vratislavská ◽  
Pavel Hojač
Keyword(s):  
Phase Composition ◽  
Chemical Composition ◽  
Metallic Iron ◽  
Glass Phase ◽  
Iron Ore ◽  
Shaft Furnace ◽  
Early Period ◽  
Direct Production ◽  
Spherical Inclusions ◽  
Furnace Slag

During experimental smelting of iron in a replica of historical shaft furnace, which was held at the Buchlov Castle in 2018, charcoal and Mn-enriched pelosiderite-limonite iron ore from the locality Strážovice near Kyjov were used. The obtained furnace slag is practically completely formed by glass phase; only rare small domains also contain olivine. The glass phase is compositionally heterogeneous and contains 0.7 - 10.7 wt. % MnO, whereas olivine corresponds to fayalite with elevated contents of tephroite (ca. 12 mol. %), forsterite (ca. 4 mol. %) and dicalciumsilicate (1 mol. %) components. The produced metallic iron is also compositionally heterogeneous, rich in phosphorus and in places it contains small spherical inclusions of pyrrhotite. The phase composition of slag differs significantly from those of typical iron slags. The reason can be seen either in anomalous chemical composition of used ore (the elevated contents of Mn could potentially act as an inhibitor of crystallization), or in too high temperatures during smelting (the phase relations in metallic iron suggest temperatures exceeding 1500 °C) in combination with rapid cooling of the furnace content after finishing of smelting. Both phase composition of slag as well as chemical composition of individual slag phases and metallic iron are significantly different from those of local historical artefacts from the period of usage of technology of direct production of iron. These findings do not support the idea that local pelosiderite iron ores were used for production of iron already during this early period.

Utilization of Iron Tailings for High Strength Fired Brick

2012 ◽  
Vol 550-553 ◽  
pp. 2373-2377
Author(s):  
Wei Juan Guo ◽  
Gao Xiang Du ◽  
Ran Fang Zuo ◽  
Jing Hui Liao
Keyword(s):  
Phase Composition ◽  
Mechanical Strength ◽  
Water Absorption ◽  
Bulk Density ◽  
Firing Temperature ◽  
Glass Phase ◽  
High Strength ◽  
Optimum Conditions ◽  
Crystalline Phases ◽  
Fired Bricks

his paper studies the feasibility of preparation high strength fired bricks from iron tailings with addition of clay and coal gangue. The results indicated that the optimum conditions were found to be that the hematite tailings content were 35%–50%; the firing temperature was 1000 °C. Under these conditions, the mechanical strength, the water absorption and the bulk density of the fired bricks were 21.17–26.14 MPa, 14.55–15.47% and 1.648–1.629g/cm3, respectively, these were well conformed to standards MU20 of Chinese Fired Common Bricks Standard (GB/T5101-2003).The phase composition and microstructure of the fired specimen were characterized by XRD and SEM. The results showed that the major crystalline phases present in fired brick were quartz, albite, amphibole, hematite and muscovite, and glass phase encapsulated and cement the crystalline phases forming strong entirety which promoted the strength of bricks.

scholarly journals Production and investigation of powders for additive synthesis from a new beta-solidifying TiAl-based alloy

2021 ◽  
Vol 2144 (1) ◽  
pp. 012004
Author(s):  
P V Panin ◽  
I A Bogachev ◽  
E A Lukina
Keyword(s):  
Phase Composition ◽  
Chemical Composition ◽  
Equilibrium Phase ◽  
Fold Increase ◽  
Induction Melting ◽  
Technological Properties ◽  
Powder Flowability ◽  
Powder Particles ◽  
Additive Synthesis ◽  
Composition Structure

Abstract Chemical composition, structure, and technological properties have been investigated for metal powder compositions (MPCs) of a new six-component TiAl-based alloy with Gd microadditions: Ti-31.0Al-2.5V-2.5Nb-2.5Cr-0.4Gd, wt.% (Ti-44.5Al-2V-1Nb-2Cr-0.1Gd, at.%). Three MPCs fractions (10–63, 40–100, 80–120 μm) were produced by electrode induction melting and inert gas atomization technique and targeted for the additive synthesis of parts. It is shown that the chemical composition of the MPCs for the main elements corresponds to that of the electrode. In contrast, a 1.5-fold increase of the oxygen content in the MPCs was observed, which is being the result of natural oxidation of powder particles upon air environment due to developed specific surface. It has been determined that the phase composition of the MPCs (γ+α(α2)+β) differs from the equilibrium phase composition of the electrode (γ+α2)+β0/B2) and corresponds to a rapidly quenched metastable state, which indicates high solidification rates in the atomization process, exceeding critical cooling rates of the alloy. The technological properties, specifically the powder flowability, were found to be improved for 40–100 and 80–120 μm fractions, making them applicable for additive synthesis of parts from the studied alloy by selective electron-beam melting method

scholarly journals Determination of Chromite Sands Suitability for Use in Moulding Sands

2017 ◽  
Vol 17 (2) ◽  
pp. 107-110
Author(s):  
K. Stec ◽  
J. Podwórny ◽  
B. Psiuk ◽  
Ł. Kozakiewicz
Keyword(s):  
Phase Composition ◽  
High Temperature ◽  
Chemical Composition ◽  
Chemical Properties ◽  
Grinding Process ◽  
X Ray Diffraction ◽  
Scanning Microscope ◽  
Spectroscopy Technique ◽  
X Ray

Abstract Using the available analytical methods, including the determination of chemical composition using wavelength-dispersive X-ray fluorescent spectroscopy technique and phase composition determined using X-ray diffraction, microstructural observations in a highresolution scanning microscope equipped with an X-ray microanalysis system as well as determination of characteristic softening and sintering temperatures using high-temperature microscope, the properties of particular chromite sands were defined. For the study has been typed reference sand with chemical properties, physical and thermal, treated as standard, and the sands of the regeneration process and the grinding process. Using these kinds of sand in foundries resulted in the occurrence of the phenomenon of the molding mass sintering. Impurities were identified and causes of sintering of a moulding sand based on chromite sand were characterized. Next, research methods enabling a quick evaluation of chromite sand suitability for use in the preparation of moulding sands were selected.

Chemical composition of iron sulphides contained in dust from pyrometallurgical Zn and Pb production

2021 ◽  
pp. geochem2020-073
Author(s):  
Katarzyna Nowińska ◽  
Zdzisław Adamczyk
Keyword(s):  
Phase Composition ◽  
Chemical Composition ◽  
Production Process ◽  
Zinc Sulphide ◽  
Iron Sulphide ◽  
Lead Sulphide ◽  
Iron Sulphides ◽  
Mineral Components

The paper presents results of investigations of the chemical composition of iron sulphides contained in dust from the pyrometallurgical production process of zinc and lead. The main mineral components of these dusts are sphalerite, galena, iron sulphide – pyrite, zincite, anglesite and probably kirchsteinite. The tests performed have demonstrated that the chemical composition of iron sulphide grains was not close to stoichiometric, the grains were non-uniform in terms of phase composition, and they always included admixtures in the form of inclusions of other sulphides, i.e. zinc sulphide and lead sulphide, and accompanying elements (Ca, Mn, Se, As, Ag, Cu, Cd).

scholarly journals Structure of Alloys for (Sm,Zr)(Co,Cu,Fe)Z Permanent Magnets: First Level of Heterogeneity

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3893 ◽  
Author(s):  
Andrey G. Dormidontov ◽  
Natalia B. Kolchugina ◽  
Nikolay A. Dormidontov ◽  
Yury V. Milov
Keyword(s):  
Phase Composition ◽  
Quantitative Analysis ◽  
Chemical Composition ◽  
Permanent Magnets ◽  
Composition Range ◽  
Structural Phase ◽  
High Coercivity ◽  
Structural Components ◽  
Structural Formation ◽  
Hysteretic Properties

An original vision for the structural formation of (Sm,Zr)(Co,Cu,Fe)Z alloys, the compositions of which show promise for manufacturing high-coercivity permanent magnets, is reported. Foundations arising from the quantitative analysis of alloy microstructures as the first, coarse, level of heterogeneity are considered. The structure of the alloys, in optical resolutions, is shown to be characterized by three structural phase components, which are denoted as A, B, and C and based on the 1:5, 2:17, and 2:7 phases, respectively. As the chemical composition of alloys changes monotonically, the quantitative relationships of the components A, B, and C vary over wide ranges. In this case, the hysteretic properties of the (Sm,Zr)(Co,Cu,Fe)Z alloys in the high-coercivity state are strictly controlled by the volume fractions of the A and B structural components. Based on quantitative relationships of the A, B, and C structural components for the (R,Zr)(Co,Cu,Fe)Z alloys with R = Gd or Sm, sketches of quasi-ternary sections of the (Co,Cu,Fe)-R-Zr phase diagrams at temperatures of 1160–1190 °C and isopleths for the 2:17–2:7 phase composition range of the (Co,Cu,Fe)–Sm–Zr system were constructed.

The Structure of Coatings Obtained in a ZnAl23Si Bath by the Batch Hot Dip Method

2015 ◽  
Vol 226 ◽  
pp. 155-160 ◽  
Author(s):  
Henryk Kania
Keyword(s):  
Phase Composition ◽  
Chemical Composition ◽  
Growth Kinetics ◽  
Coating Thickness ◽  
Silicon Steel ◽  
Structural Components ◽  
Uniform Thickness ◽  
External Layer ◽  
Structure Of Coatings ◽  
Kinetics Of

In the paper the results of tests on obtaining ZnAl23Si coatings on low-silicon steel by use of the batch hot dip method have been presented. The growth kinetics of coatings obtained in a ZnAl23 bath with the content of 1% and 2% of Si has been defined. The structure has been developed, the chemical composition of particular structural components of the coating and its phase composition have been established. It has been determined that coatings obtained in the ZnAl23Si bath are continuous and they have uniform thickness. The presence of silicon in the bath allows to reduce excessive coating thickness. The coating is composed of an external layer which is formed by the bath components and of a diffusion layer of the intermetallic FeAl3phase.

The character of the structure formation of model alloys of the Fe-Cr-(Zr, Zr-B) system synthesized by powder metallurgy

2020 ◽  
Vol 2 (100) ◽  
pp. 49-57
Author(s):  
Z.A. Duriagina ◽  
M.R. Romanyshyn ◽  
V.V. Kulyk ◽  
T.M. Kovbasiuk ◽  
A.M. Trostianchyn ◽  
...  
Keyword(s):  
Phase Composition ◽  
Powder Metallurgy ◽  
Chemical Composition ◽  
Structure Formation ◽  
Xrd Analysis ◽  
Model Alloy ◽  
Phase Identification ◽  
Laves Phases ◽  
Cr System ◽  
Sintered Alloys

Purpose: The purpose of the work is to synthesize and investigate the character of structure formation, phase composition and properties of model alloys Fe75Cr25, Fe70Cr25Zr5, and Fe69Cr25Zr5B1. Design/methodology/approach: Model alloys are created using traditional powder metallurgy approaches. The sintering process was carried out in an electric arc furnace with a tungsten cathode in a purified argon atmosphere under a pressure of 6·104 Pa on a water cooled copper anode. Annealing of sintered alloys was carried out at a temperature of 800°C for 3 h in an electrocorundum tube. The XRD analysis was performed on diffractometers DRON-3.0M and DRON-4.0M. Microstructure study and phase identification were performed on a REMMA-102-02 scanning electron microscope. The microhardness was measured on a PMT-3M microhardness meter. Findings: When alloying a model alloy of the Fe-Cr system with zirconium in an amount of up to 5%, it is possible to obtain a microstructure of a composite type consisting of a mechanical mixture of a basic Fe2(Cr) solid solution, solid solutions based on Laves phases and dispersive precipitates of these phases of Fe2Zr and FeCrZr compositions. In alloys of such systems or in coatings formed based on such systems, an increase in hardness and wear resistance and creep resistance at a temperature about 800°C will be reached. Research limitations/implications: The obtained results were verified during laser doping with powder mixtures of appropriate composition on stainless steels of ferrite and ferrite-martensitic classes. Practical implications: The character of the structure formation of model alloys and the determined phase transformations in the Fe-Cr, Fe-Cr-Zr, and Fe-Cr-B-Zr systems can be used to improve the chemical composition of alloying plasters during the formation of ferrite and ferrite-martensitic stainless steel coatings. Originality/value: The model alloys were synthesized and their phase composition and microstructure were studied; also, their microhardness was measured. The influence of the chemical composition of the studied materials on the character of structure formation and their properties was analysed.

Enriched primary kaolins of Uzbekistan as a raw material for chamotte lightweight refractories

2019 ◽  
pp. 8-11 ◽  
Author(s):  
M. Kh. Rumi ◽  
Sh. K. Irmatova ◽  
Sh. A. Fayziev ◽  
E. P. Mansurova ◽  
E. M. Urazaeva ◽  
...  
Keyword(s):  
Phase Composition ◽  
Water Absorption ◽  
Phase Formation ◽  
Formation Process ◽  
Raw Material ◽  
Promising Material ◽  
Crystalline Phases ◽  
Optimal Ratio ◽  
The Stability ◽  
Phase Formation Process

The results of studies of the phase formation process of enriched primary kaolins of the Angren and Samarkand fields during firing in the range of 1250‒1400 oC are presented. It is shown that the stability of the phase composition, the optimal ratio of the crystalline phases, shrinkage and water absorption indices allow us to consider the enriched kaolin of the Samarkand field as a promising material for making chamotte lightweight refractories. Ill. 3. Ref. 11. Tab. 3. 

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