Statistical Analysis of Metal Particles Forming during Reduction of Oxides with Low Iron Content

2018 ◽  
Vol 284 ◽  
pp. 673-678 ◽  
Author(s):  
A.S. Bilgenov ◽  
Yu. Kapelyushin ◽  
P.A. Gamov
Keyword(s):  
Solid Phase ◽  
Metallurgical Industry ◽  
Metal Particles ◽  
Low Grade ◽  
State Reduction ◽  
Reduction Behavior ◽  
Phase Reduction ◽  
Ore Minerals ◽  
Average Size ◽  
Solid State Reduction

Metallurgical Industry slowly moves towards wider utilization of complex ore minerals. Reduction behavior of complex crystalline structures can hardly be interpreted applying kinetic modeling adopted for pure oxides. The quantitative mathematical analysis of the metal particles forming during solid state reduction of a complex mineral has been suggested. The analysis with 95% reliability showed that during solid phase reduction of dunite at 1300 °C for 60 min about 360 particles with an average size about 0.62 mm formed from the total area S = 20880 mm. Such an approach could be useful for development of sophisticated kinetic models applied for reduction of a low-grade complex ore.

scholarly journals Feasibility of nickel extraction from Indian chromite overburden by solid state reduction and smelting route

2020 ◽  
Vol 56 (2) ◽  
pp. 229-235
Author(s):  
P. Ganesh ◽  
Dishwar Kumar ◽  
S. Agrawal ◽  
Mandal Kumar ◽  
N. Sahu ◽  
...  
Keyword(s):  
Solid State ◽  
Horizontal Tube ◽  
Low Grade ◽  
State Reduction ◽  
Nickel Extraction ◽  
Reducing Atmosphere ◽  
Chromite Overburden ◽  
Solid State Reduction ◽  
Horizontal Tube Furnace ◽  
Direct Smelting

The present work demonstrates the extraction of nickel from low-grade chromite overburden by using solid state reduction and direct smelting route. Goethite & Quartz are present as major phases whereas chromite, hematite were identified as minor phases in the mineral. Solid state reduction of pellets were carried out inside a horizontal tube furnace at 1000?C, 1200?C, 1400?C for 30, 60, 90 and 120 minutes respectively with creating reducing atmosphere. Pellets of varying basicity (i.e. 0.5, 0.6, 0.7, 0.8 and 0.9) were used directly in the EAF for smelting studies. Highest percent of nickel (2%) having ~ 91% recovery were obtained in solid state reduction route for pellets which was reduced at 1400?C for 120 minute. Similar recovery (~90%) of nickel was obtained inside the ingot (0.67% Ni ) by using pellets of 0.9 basicity through smelting route. From the present investigation, it could be concluded that the solid state reduction as well as smelting routes are feasible for the recovery of nickel from low grade chromite overburden. The production of nickel pig (low grade ferronickel) could also be feasible by smelting route.

scholarly journals ELECTRON THEORY OF METALS REDUCTION: THEORY AND METHODS OF METALS EXTRACTION FROM VARIOUS TYPES OF ORE

2019 ◽  
Vol 62 (5) ◽  
pp. 407-417 ◽  
Author(s):  
V. E. Roshchin ◽  
P. A. Gamov ◽  
A. V. Roshchin ◽  
S. P. Salikhov
Keyword(s):  
Crystal Lattice ◽  
Solid Phase ◽  
Reducing Agent ◽  
Metal Phase ◽  
Low Grade ◽  
Reduction Mechanism ◽  
Electron Theory ◽  
Phase Reduction ◽  
Reduction Of Iron ◽  
Anion Vacancies

The present work analyzes the existing mechanism of solid-phase metals reduction from oxides. It was shown that the existed mechanisms of reduction do not explain the diversity of the practical results leading to a generally accepted opinion that there is no single uniform reduction mechanism. This study presents the results of the solid-phase reduction of metals from lump magnetite, siderite, titanomagnetite and chromite types of ore by carbon from various deposits. The obtained results were compared with the results of reduction of chromium, silicon and aluminum by carbon from pure oxides. Change in the electrical characteristics and analysis of the processes of electron- and mass transfer under reducing conditions were performed to clarify the general theoretical concepts of reduction mechanism. It has been concluded that there is general process of transformation of the crystal lattice of oxide into the crystal lattice of metal for reduction of different metals. The positions of electron theory for solid-phase reduction of metals from crystal lattice of oxides were developed using the basic concepts of chemistry, solid state physics about imperfect crystals, quantum mechanics and character of electron distribution and transfer in metals and ionic semiconductors. The theory embraces all the known results of reduction with formation of metal on the surface of high-grade lump ore, nucleation of metal inside of the complex and low-grade types of ore and formation and sublimation of suboxides. Major ideas of the developing theory of electron reduction have been formulated on the basis of metals reduction as a result of the exchange of electrons between the reducing agent and metal cations in oxides by means of the charged anion vacancies formed on the surface and their scattering in the volume. The transformation of the cations’ ionic bond in oxides into metallic bond of the metal phase on the surface (or inside of the oxide lattice) occurs without the displacement of the cations over significant distances and thermodynamic difficulties for the formation of metallic nucleus when the charged anion vacancies merge (skipping the stage of formation of the atoms of metal). There might be no direct contact between the metal and the reducing agent in case of formation of the metal phase inside of the oxide volume. As a result, harmful impurities from the reducing agent, e.g. carbon and sulphur, do not penetrate into iron during reduction of complex and low-grade types of ore. Therefore, for the reduction of iron from such an ore, it is possible to utilize a low-quality reducing agent, e.g. steam coal. The selective solid-phase reduction of iron from lump complex ore makes it possible to obtain a metal-oxide composite material containing pure DRI and valuable oxides which are difficult for reduction, i.e. oxides of magnesium, titanium and vanadium.

“In-Situ Raman Spectroscopy of Electronic Processes in Fullerene Thin Films

2002 ◽  
Vol 725 ◽  
Author(s):  
S.B. Phelan ◽  
B.S. O'Connell ◽  
G. Farrell ◽  
G. Chambers ◽  
H.J. Byrne
Keyword(s):  
Thin Film ◽  
Indium Tin Oxide ◽  
Low Temperatures ◽  
In Situ Raman Spectroscopy ◽  
State Reduction ◽  
In Situ Raman ◽  
Linear Behavior ◽  
Current Voltage ◽  
Solid State Reduction

AbstractThe current voltage characteristics of C60 thin film sandwich structures fabricated by vacuum deposition on indium tin oxide (ITO) with an aluminium top electrode are presented and discussed. A strongly non-linear behavior and a sharp increase in the device conductivity was observed at relatively low voltages (∼2V), at both room and low temperatures (20K). At room temperature the system is seen to collapse, and in situ Raman measurements indicate a solid state reduction of the fullerene thin film to form a polymeric state. The high conductivity state was seen to be stable at elevated voltages and low temperatures. This state is seen to be reversible with the application of high voltages. At these high voltages the C60 film was seen to sporadically emit white light at randomly localized points analogous to the much documented Electroluminescence in single crystals.

Research status of microwave-assisted reduction technology of pyrolusite

2020 ◽  
Vol 07 ◽  
Author(s):  
Li Qiannan ◽  
Ling Yeqing ◽  
Zheng Hewen ◽  
Yang Zhi
Keyword(s):  
Metallurgical Industry ◽  
Raw Material ◽  
Utilization Efficiency ◽  
Low Grade ◽  
Manganese Ore ◽  
Effective Utilization ◽  
Research Status ◽  
Strategic Position ◽  
Research Intensity ◽  
Stable Development

: Manganese ore is an important metallurgical raw material that holds an important strategic position in the national economy of China. However, the grade of manganese ore in the country is mostly low, and the utilization efficiency of lowgrade manganese ore resources is low, which seriously restrict the healthy and stable development of China’s metallurgical industry. As a new green heating method, microwave is expected to address the problems of conventional methods and realize the effective utilization of low-grade manganese ore. In this paper, the research status of the microwave composite reduction of pyrolusite in recent years is reviewed. Microwave plays an important role in metallurgy, and it is the current direction pursued to improve the research intensity of microwave heating and extend it to actual industrial processes.

scholarly journals Influence of Cu on the Improvement of Magnetic Properties and Structure of L10 FePt Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1097
Author(s):  
Luran Zhang ◽  
Xinchen Du ◽  
Hongjie Lu ◽  
Dandan Gao ◽  
Huan Liu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Annealing Temperature ◽  
Reduction Method ◽  
Solid Phase ◽  
Average Particle Size ◽  
Fept Nanoparticles ◽  
Average Particle ◽  
Phase Reduction ◽  
Different Temperatures ◽  
One Step

L10 ordered FePt and FePtCu nanoparticles (NPs) with a good dispersion were successfully fabricated by a simple, green, one-step solid-phase reduction method. Fe (acac)3, Pt (acac)2, and CuO as the precursors were dispersed in NaCl and annealed at different temperatures with an H2-containing atmosphere. As the annealing temperature increased, the chemical order parameter (S), average particle size (D), coercivity (Hc), and saturation magnetization (Ms) of FePt and FePtCu NPs increased and the size distribution range of the particles became wider. The ordered degree, D, Hc, and Ms of FePt NPs were greatly improved by adding 5% Cu. The highest S, D, Hc, and Ms were obtained when FePtCu NPs annealed at 750 °C, which were 0.91, 4.87 nm, 12,200 Oe, and 23.38 emu/g, respectively. The structure and magnetic properties of FePt and FePtCu NPs at different annealing temperatures were investigated and the formation mechanism of FePt and FePtCu NPs were discussed in detail.

Ammonia Leaching of Zinc from Low-grade Oxide Zinc Ores Using the Enhancement of the Microwave Irradiation

2017 ◽  
Vol 16 (3) ◽  
Author(s):  
Shiwei Li ◽  
Haoyu Li ◽  
Weiheng Chen ◽  
Jinhui Peng ◽  
Aiyuan Ma ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Microwave Irradiation ◽  
Solid Phase ◽  
Ammonia Concentration ◽  
Low Grade ◽  
Leaching Rate ◽  
Small Particles ◽  
Mineral Phase ◽  
Total Ammonia ◽  
Ammonia Leaching

AbstractIrradiated roast treatment and the ammonia leaching processing were conducted to deal with the low-grade oxide zinc ores. The ZnCO3phase was hard to be attended, which was the reason for the low leaching rate of the complicated zinc ores. The mineral phase transformation of the ZnCO3phase was generated after the ores irradiated in the microwave at the temperature of 673 K. The irradiated ores generated more small particles, it was the reason that the leaching rate of the complicated zinc ores was increased. When the leaching processing of the irradiated roasted ores was conducted under the conditions of the total ammonia concentration of 6 mol/L, the liquid to solid phase ratio of 11:1, the leaching temperature of 298 K, the leaching time of 150 min and the stirring speed of 400 rpm, 88.3 % of zinc could be achieved, which was the maximum leaching rate of the irradiated ores.

Evaluation of Orchid-Like Aroma Between Different Grades of Taiping Houkui Tea by Solid-Phase Microextraction and Comprehensive Two-Dimensional Gas Chromatography Coupled with Time-of-Fight Mass Spectrometry

2020 ◽  
Vol 103 (2) ◽  
pp. 433-438
Author(s):  
Chen Qi ◽  
Guo Tianyang ◽  
Wu Qiong ◽  
Yao Jian ◽  
Liao Renyi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Low Grade ◽  
Two Dimensional ◽  
Material Basis ◽  
Quality Grade ◽  
Gaseous Sample ◽  
Grade One

Abstract Background: Taiping houkui tea won the title of “the King of Green Tea” at the International Tea Exposition in 2004, which had an orchid fragrance but the material basis of the orchid fragrance had not been revealed yet. Objective: To investigate the material basis of the orchid fragrance and identify the quality grade of Taiping houkui tea. Methods: A method was developed for evaluating orchid-like aroma between different grades Taiping houkui tea by solid-phase micro extraction (SPME) and comprehensive two-dimensional gas chromatography coupled with time-of-fight mass spectrometry (GC×GC-TOFMS). The crushed tea sample in a 25 mL headspace bottle was incubated at 90°C for 10 min. Then the gaseous sample was extracted by SPME divinylbenzene/polydimethylsiloxane fiber for 50 min and thermally desorpted at 250°C for 2 min. Results: In total, 735 volatile compounds were determined by SPME- GC×GC-TOFMS and 15 compounds were related to orchid-like aroma. Conclusions: The high-quality Taiping houkui tea has the orchid fragrance and the low-grade one does not; thus orchid-like aroma can be used as a reference of grades of Taiping houkui tea. Highlights: Thirty different grades of Taiping houkui tea samples were compared and analyzed experimentally, and the results showed that the special aroma substances, which played a key role in grade discrimination of Taiping houkui tea, were found by the statistical method.

Research on Exploration of Mineral Processing for a Iron Ore

2015 ◽  
Vol 1094 ◽  
pp. 397-400
Author(s):  
Xian Xie ◽  
Zi Xuan Yang ◽  
Xiong Tong ◽  
Ji Yong Li
Keyword(s):  
Magnetic Separation ◽  
Calcium Oxide ◽  
Iron Ore ◽  
Mineral Processing ◽  
Low Grade ◽  
Iron Minerals ◽  
Iron Mineral ◽  
Ore Minerals ◽  
Separation Test

Iron ore minerals are mainly silicate-type iron minerals in raw ore, and its distribution rate was 51.93%; followed by magnetic iron, and its distribution rate was 36.81%; content and distribution rate of other minerals was very low; element grade of iron, phosphorus, sulfur, silica were 11.90%, 0.043%, 0.013% and 45.23%, the main gangue were silica and calcium oxide, recyclable iron minerals mainly is magnetic iron mineral. Due to the grade of iron of raw ore and the amounts of optional magnetite was relatively little, in order to investigate the optional of low-grade ore, weak magnetic separation test and weak magnetic separation tailings-strong magnetic separation test were put into effect.

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