Study effect of Na2SO4 dosage and graphite on the selective reduction of saprolite from nickel grade, recovery, and iron-nickel grain size

2021 ◽  
Author(s):  
Fathan Bahfie ◽  
Azwar Manaf ◽  
Widi Astuti ◽  
Fajar Nurjaman ◽  
Erik Prasetyo ◽  
...  
Keyword(s):  
Grain Size ◽  
Selective Reduction ◽  
Iron Nickel ◽  
Nickel Grade

Study of Low-Grade Nickel Laterite Processing Using Palm Shell Charcoal as Reductant

2020 ◽  
Vol 1000 ◽  
pp. 436-446
Author(s):  
Bambang Suharno ◽  
Nolzha Primadha Ilman ◽  
Achmad Shofi ◽  
Deni Ferdian ◽  
Fajar Nurjaman
Keyword(s):  
Sodium Sulfate ◽  
Selective Reduction ◽  
Reduction Process ◽  
Low Grade ◽  
X Ray Diffraction ◽  
X Ray ◽  
Palm Shell ◽  
Higher Temperature ◽  
Nickel Grade

This study was conducted to investigate the effect of palm shell charcoal reductant in the selective reduction of nickel ore with the addition of additive at various temperatures and times. In this present work, 10 wt. % of sodium sulfate as additive and 5, 10, 15 wt. % of palm shell charcoal as reductants were used. The reduction of nickel ore was performed at 950oC, 1050oC, and 1150oC for 60, 90, and 120 minutes. A wet magnetic separation method was then carried out to separate the concentrates and tailings. Characterization of reduced ore was performed by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), while the composition of ferronickel in concentrate was identified by X-Ray Fluorescence (XRF). The result showed that the higher temperature reduction, the higher of nickel grade, and its recovery at the concentrate. Nevertheless, the longer reduction time and the more reductant in nickel ore lowering the nickel grade and its recovery in the concentrate. The optimum condition in this selective reduction process was obtained with the addition of 5 wt. % of reductant and 10 wt. % of sodium sulfate in nickel ore, which was reduced at 1150oC for 60 minutes. It resulted in 4.60% and 73.23% for nickel grade and its recovery, respectively.

AN INVESTIGATION ON THE EFFECT OF ELECTROCHEMICAL ADSORBATES ON PROPERTIES OF ELECTRODEPOSITED NANOCRYSTALLINE Fe–Ni ALLOYS

2013 ◽  
Vol 12 (01) ◽  
pp. 1350002 ◽  
Author(s):  
A. SANATY-ZADEH ◽  
K. RAEISSI ◽  
A. SAIDI
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Cathode Surface ◽  
Iron Hydroxide ◽  
Ni Alloys ◽  
Fe Content ◽  
Iron Nickel ◽  
Current Densities ◽  
Eis Measurements ◽  
Deposition Current Density

Iron–Nickel nanocrystalline alloys were electrodeposited from a simple chloride bath using different current densities. The composition and grain size of deposited alloys were in the range of 29–42% Ni and 8–11 nm, respectively. The alloy deposited at lower current density showed higher microhardness, which is most probably due to its higher Fe content and lower grain size. EIS measurements showed that the iron hydroxide species can be formed and adsorbed onto the cathode surface during the deposition. Such species showed an inhibitive effect not only on Ni ion reduction but also on grain growth. By increasing the deposition current density, the adsorption tendency of iron hydroxide was reduced which caused an increase in grain size and Ni percentage of the alloy produced.

scholarly journals Fe-Ni ALLOY ELECTRODEPOSITION FROM SIMPLE AND COMPLEX TYPE SULFATE ELECTROLYTES CONTAINING Ni/Fe RATIO OF 1 AND 12

2014 ◽  
Vol 44 (1) ◽  
pp. 51-56 ◽  
Author(s):  
M. Moniruzzaman ◽  
K.M. Shorowordi ◽  
A. Azam ◽  
M.F.N. Taufique
Keyword(s):  
Grain Size ◽  
Current Density ◽  
High Current Density ◽  
Complexing Agents ◽  
Alloy Electrodeposition ◽  
Fine Grained ◽  
Ni Alloy ◽  
Iron Nickel ◽  
High Degree ◽  
Density Results

Iron-nickel (Fe-Ni) alloy electrodeposition has been conducted from simple and complex baths having Ni/Fe ratio of 1 and 12. The applied current density varies from 30 to 100 mA/cm2. The coating composition, morphology and microhardness are measured and characterized by SEM/EDX and Shimadzu microhardness tester. The percentage of Ni in the coating increases with increasing current density and the Ni/Fe ratio of electrolytes which is supported by the alloy deposition principle. Fine grained and smooth coating without microcracking is obtained from the complex baths. Complexing agents are supposed to reduce the deposit stress developed during electrodeposition. Increase in Ni/Fe ratio in the bath as well as current density results in decreasing grain size of the deposits. High current density is believed to give rise to a high degree of adatoms at the electrode surface and high degree of adatoms decreases the grain size. Microhardness of the coating increases with the increase of bath Ni/Fe ratio as well as current density of electrodeposition. DOI: http://dx.doi.org/10.3329/jme.v44i1.19498

Study on the Microstructure and Magnetic Domain Struture of the Soft Magentic Alloy 1J50

2016 ◽  
Vol 852 ◽  
pp. 187-193
Author(s):  
Chun Hong Li ◽  
Deng Ming Chen ◽  
Yi Long Ma ◽  
An Ruo Zhou ◽  
Si Huang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
High Performance ◽  
Magnetic Domain ◽  
Domain Size ◽  
Magnetic Domains ◽  
Soft Magnetic ◽  
Soft Magnetic Alloys ◽  
Before And After ◽  
Iron Nickel

1J50 alloy is one of the major iron–nickel compositions,well-known for high flux density, low coercivity and high saturation induction.In this study,the microstructure and magnetic domain struture of the soft magentic alloy 1J50 before and after heat treatment (HT) were studied using scanning electron microscopy (SEM)、transmission electronmicroscopy (TEM) and magnetic force microscope (MFM). The results showed that grain size and domain size were small before HT,there was high-density dialocation in the alloy.After HT,grain size increased, the internal stress, dislocation and other defects were reduced,magnetic domains became wider,the number of the domain decreased and the exchange energy between the magnetic domain reduced,leading to the decrease of the coercivity and increase of permeability.It was also found that the curie temperature was not changed after heat treatment. The research can provide theoretically a reliable way for preparing Fe-Ni soft magnetic alloys with high performance.

scholarly journals Effect of Heat Treatment on Microstructure and Creep Behavior of Fe-40Ni-24Cr Alloy

2021 ◽  
Vol 11 (17) ◽  
pp. 7951
Author(s):  
Maureen Mudang ◽  
Esah Hamzah ◽  
Hamid Reza Bakhsheshi-Rad ◽  
Filippo Berto
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Creep Behavior ◽  
Gas Turbines ◽  
High Temperature Creep ◽  
Creep Properties ◽  
Temperature Creep ◽  
Heat Treated ◽  
Sliding Mechanism ◽  
Iron Nickel

Iron-nickel-chromium (Fe-Ni-Cr) alloy Haynes HR120 is an iron-nickel-based superalloy, which is extensively used in gas turbines. Hence, the materials for the fabrication of steam turbine blades should present great mechanical characteristics and creep properties. In this study, Fe-40Ni-24Cr was heat-treated at temperatures from 950 to 1250 °C. High temperature creep behavior and microstructure evolution of the selected heat-treated (1050 °C, 1200 °C, 1225 °C and 1250 °C) Fe-40Ni-24Cr alloy were assessed at temperatures of 800 °C and 900 °C under 100 MPa stress. The alloy consisted of titanium and niobium rich precipitates, namely NbC, (Nb,Ti)C, TiN and Ti(C,N) distributed in the matrix grain boundaries, which enhance the creep properties of the alloy. The hardness of heat-treated Fe-40Ni-24Cr alloy decreased with increasing temperature and grain size. The creep strain of the Fe-40Ni-24Cr alloy increased with escalation in the creep time and the temperature being under constant applied stress. Fe-40Ni-24Cr alloy shows a decrease in steady-state creep rate with an increase in grain size from 62 μm to 183 μm due to the grain boundary sliding mechanism and 183 μm to 312 μm due to the occurrence of dislocation climb. This result exhibited that grain size has a significant influence on the alloys’ high temperature creep properties.

scholarly journals Parameters Influencing Steady-State Grain Size of Pure Metals Processed by High-Pressure Torsion

2012 ◽  
Vol 706-709 ◽  
pp. 3034-3039 ◽  
Author(s):  
Kaveh Edalati ◽  
Z. Horita
Keyword(s):  
Grain Size ◽  
High Pressure ◽  
Steady State ◽  
High Pressure Torsion ◽  
Electron Back Scatter Diffraction ◽  
Logarithmic Scale ◽  
Transmission Electron ◽  
Nickel Copper ◽  
Iron Nickel ◽  
Copper Zinc

High purity elements such as magnesium, aluminum, silicon, titanium, vanadium, iron, nickel, copper, zinc, zirconium, molybdenum, palladium, silver, indium, tin, hafnium, gold and lead were processed by high-pressure torsion and subsequently evaluated by microstructural examinations and Vickers microhardness measurement. The grain size at the steady state, where the grain size and hardness remain unchanged with straining, was determined using either transmission electron microscopy, electron back-scatter diffraction analysis and/or optical microscopy. It is found that the steady state grain sizes are at the submicrometer level in elements with metallic bonding and at the nanometer level in elements with covalent bonding. The correlations between the steady-state grain size and the physical properties of metals are examined and it is found that the atomic bond energy and the homologous temperature are important parameters influencing the steady-state grain size after processing by HPT. A linear correlation between the hardness and grain size at the steady state is achieved by plotting the hardness normalized by the shear modulus against the grain size normalized by the Burgers vector in the logarithmic scale.

Electroforming and Mechanical Properties of Iron-Nickel Alloy Foil

1979 ◽  
Vol 21 (6) ◽  
pp. 411-417 ◽  
Author(s):  
S. H. F. Lai ◽  
J. A. McGeough
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Hydrogen Embrittlement ◽  
Nickel Alloy ◽  
Current Density ◽  
Nickel Chloride ◽  
Iron Foil ◽  
Alloy Foil ◽  
Iron Nickel ◽  
Current Densities

A method of electroforming smooth, bright, iron-nickel alloy foil, of thickness about 0.1 mm, is developed. The electrolyte, mainly a solution of ferrous chloride and nickel chloride, is operated at a temperature of 95 °C, and at current densities of between 5 and 20 A/dm2. Below that temperature, and at current densities greater than 20 A/dm2, the foil becomes cracked. The amount of nickel co-deposited in the alloy can be increased up to a limit of 6.24 per cent, by reducing the current density and/or increasing the concentration of nickel chloride in the electrolyte. As the nickel content of the foil rises, the material suffers increasingly from hydrogen embrittlement. The main mechanical properties of the alloy foil are more affected by hydrogen embrittlement, the amount of which is influenced by current density and the concentration of nickel chloride, than by changes in grain size. This behaviour is in contrast with that of electroformed iron foil, for which the mechanical properties are largely controlled by the influence of the current density and electrolyte temperature upon its grain size. However, when the other process conditions are held constant, the mechanical properties of the alloy foil behave like the iron foil in decreasing with increasing foil thickness, owing to increases in average grain size.

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