scholarly journals Removal of Tramp Elements within 7075 Alloy by Super-Gravity Aided Rheorefining Method

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 701 ◽  
Author(s):  
Lei Guo ◽  
Xiaochun Wen ◽  
Qipeng Bao ◽  
Zhancheng Guo
Keyword(s):  
Heat Treatment ◽  
Liquid Phase ◽  
7075 Aluminum Alloy ◽  
Total Removal ◽  
Tramp Element ◽  
Removal Ratio ◽  
Gravity Coefficient ◽  
Flow Through ◽  
Solid Phases ◽  
7075 Alloy

An investigation was made on the super-gravity aided rheorefining process of recycled 7075 aluminum alloy in order to remove tramp elements. The separation temperatures in this study were selected as 609 °C, 617 °C and 625 °C. And the gravity coefficients were set as 400 G, 700 G, 1000 G. The finely distributed impurity inclusions will aggregate to the grain boundaries of Al-enriched phase during heat treatment. In the field of super-gravity, the liquid phase composed of tramp elements Zn, Cu, Mg et al. will flow through the gaps between solid Al-enriched grains and form into filtrate. Both the weight of filtrate and removal ratio of tramp element improved with the increase of gravity coefficient. The total removal ratio of tramp element decreased with the fall of temperature due to the flowability deterioration of liquid phase. The time for effective separation of liquid/solid phases with super-gravity can be restricted within 1 min.

Effect of Heat Treatment on Mechanical Properties of ECAPed 7075 Aluminum Alloy

2013 ◽  
Vol 829 ◽  
pp. 62-66 ◽  
Author(s):  
Alireza Fallahi ◽  
Hossein Hosseini-Toudeshky ◽  
Seyed Mahmoud Ghalehbandi
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Aluminum Alloy ◽  
Solution Treatment ◽  
7075 Aluminum Alloy ◽  
Ecap Processing ◽  
Good Thermal Stability ◽  
7075 Alloy

It is the objective of this study to investigate the effect of ECAP processing and heat treatment on the mechanical properties of the UFG 7075 alloy. Also the effect of post ECAP heat treatment is investigated. The alloy is processed by ECAP after annealing as well as solution treatment to produce an UFG structure. Furthermore mechanical properties and their variations during annealing and aging are investigated. The hardness of the pre-ECAP annealed and the pre-ECAP solutionised 7075 aluminum alloy has increased significantly compared with that of the CG sample. Also hardness of ECAPed specimen has not experienced significant changes in post-ECAP heat treatment and indicated that the alloy had approximately good thermal stability.

Characterizing the Effect of Processing Parameters on Temperature Distribution of 7075 Aluminum Alloy Slurry Prepared by Enthalpy Control Process

2022 ◽  
Vol 327 ◽  
pp. 263-271
Author(s):  
Gan Li ◽  
Jin Kang Peng ◽  
En Jie Dong ◽  
Juan Chen ◽  
Hong Xing Lu ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Temperature Difference ◽  
Initial Temperature ◽  
Control Process ◽  
Processing Parameters ◽  
Heating Time ◽  
7075 Aluminum Alloy ◽  
Semi Solid ◽  
7075 Alloy ◽  
Slurry Preparation

There is a strong demand for high-strength aluminum alloys such as 7075 aluminum alloy to be applied for rheocasting industry. The overriding challenge for the application of 7075 alloy is that its solid fraction is very sensitive to the variation of temperature in the range of 40% ~ 50% solid fraction, which inevitably narrows down the processing window of slurry preparation for rheocasting process. Therefore, in this work, a novel method to prepare semi-solid slurry of the 7075 alloy, so called Enthalpy Control Process (ECP), has been developed to grapple with this issue. In the method, a medium-frequency electromagnetic field was applied on the outside of slurry preparation crucible to reduce the temperature difference throughout the slurry. The effect of processing parameters, including heating power, heating time, the initial temperature of crucible and melt weight, on the temperature field of the semi-solid slurry was investigated. The results exhibited that although the all the processing parameters had a great influence on the average temperature of the slurry, heating time was the main factor affecting the maximum temperature difference of the slurry. The optimum processing parameters during ECP were found to be heating power of 7.5 KW, the initial temperature of crucible of 30 °C ~ 200 °C and melt weight of 2 kg.

Thermische Zersetzung nichtstöchiometrischer Cäsium-Silber-Gold(III)-Chloride und Darstellung von Mischkristallen zwischen Cs2AgAuCl6 und Cs2AuIAuIIICl6 / Thermal Decomposition of Nonstoichiometric Cesium-Silver-Gold(III)-Chloride and Preparation of Mixed Crystals of Cs2AgAuCl6 and Cs2Au

1980 ◽  
Vol 35 (8) ◽  
pp. 970-975 ◽  
Author(s):  
Hans Joachim Berthold ◽  
Wolfgang Ludwig
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Silver Content ◽  
Mixed Crystals ◽  
Acid Solutions ◽  
Tetragonal Modification ◽  
Lattice Constants ◽  
Cesium Ions ◽  
Hydrochloric Acid Solutions ◽  
Solid Phases

Abstract The thermal decomposition of cesium-silver-gold(III)-chloride Cs2Ag1-xAu1+x:/3Cl6 with 0 <x ≤ 0.63 at temperatures between 250 and 350 °C yields, under evolution of chlorine, mixed crystals of Cs2AgAuCl6 and Cs2AuIAuIIICl6. The composition of the latter can be described by the formula Cs2Ag1-y,AuyIAuIIICl6 with y = 2x;/ (3-x). Apart from the formation of the mixed crystals the reaction leads to CsCl as a further phase, and in the case of x < 0.35 also to some Cs2AgAuCl6. Mixed crystals with 0.23 ≤ y < 1, free from additional solid phases, can be obtained from strong hydrochloric acid solutions of Cs2AgAuCl6 and Cs2AuIAuIIICl6, which contain an excess of cesium ions. The mixed crystals are isostructural with Cs2AuIAuIIICl6 (space group I4/mmm). The variation of the lattice constants with increasing silver content confirms that the univalent silver, in contrast to the univalent gold, shows no tendency toward the formation of linear dichloro complexes. Our investigations show that the "tetragonal modification of Cs2AgAuCl6", described by Elliott and Pauling and obtained by them by heat treatment of cubic cesium-silver - gold(III)-chloride, is, in fact, CS2Ag1-y/AuyIAuIIICl6.

Micromorphology and Characterization of V2O3 Nanoparticles Produced by the Liquid Phase Reduction-Heat Treatment

2019 ◽  
Vol 944 ◽  
pp. 650-656
Author(s):  
Ming Rui Zhang ◽  
Yuan Qin ◽  
Dao Zhang ◽  
Guang Yuan Wang ◽  
Sen Yang
Keyword(s):  
Heat Treatment ◽  
Phase Composition ◽  
Liquid Phase ◽  
Thermal Treatment ◽  
Oxalic Acid ◽  
Structure And Morphology ◽  
Phase Reduction ◽  
Novel Method ◽  
Composition Structure

The liquid phase reduction-heat treatment has been used to prepare V2O3nanoparticles in this paper. It is a novel method that the precursor was developed by Oxalic acid dehydrate (H2C2O4·2H2O) reduction of V2O5powder in anhydrous ethanol. V2O3nanoparticles were successfully obtained by thermal treatment of the precursor. The phase, composition, structure, and morphology of the as-obtained samples were verified by XRD, XPS, SEM and TEM measurements. Meanwhile, the possible formation mechanism of V2O3in the heat-treatment is briefly discussed by analyzing the DSC.

scholarly journals A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2308 ◽  
Author(s):  
Kefeng Pan ◽  
Ying Li ◽  
Jiawei Zhang ◽  
Qing Zhao
Keyword(s):  
Liquid Phase ◽  
High Purity ◽  
Raw Materials ◽  
Low Cost ◽  
Crystallization Rate ◽  
Segregation Coefficient ◽  
Crystal Direction ◽  
Partial Recrystallization ◽  
Removal Ratio ◽  
Critical Raw Materials

As one of the critical raw materials, very pure gallium is important for the semiconductor and photoelectric industry. Unfortunately, refining gallium to obtain a purity that exceeds 99.99999% is very difficult. In this paper, a new, facile and efficient continuous partial recrystallization method to prepare gallium of high purity is investigated. Impurity concentrations, segregation coefficients, and the purification effect were measured. The results indicated that the contaminating elements accumulated in the liquid phase along the crystal direction. The order of the removal ratio was Cu > Mg > Pb > Cr > Zn > Fe. This corresponded to the order of the experimentally obtained segregation coefficients for each impurity: Cu < Mg < Pb < Cr < Zn < Fe. The segregation coefficient of the impurities depended strongly on the crystallization rate. All observed impurity concentrations were substantially reduced, and the purity of the gallium obtained after our refinement exceeded 99.99999%.

Preparation of Butadiene

1928 ◽  
Vol 1 (2) ◽  
pp. 208-210
Author(s):  
Stanley Francis Birch
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Liquid Phase ◽  
High Temperatures ◽  
Vapor Phase ◽  
Complex Mixture ◽  
Higher Temperature ◽  
Oil Gas

Abstract OF THE numerous methods available for the preparation of butadiene in the laboratory, those described by Thiele and by Ostromuislenskii are probably the most convenient. Both, however, suffer from the disadvantages which usually characterize operations at comparatively high temperatures; the exact conditions are difficult to find, the process is long and tedious, and finally involves the separation of the required material from a complex mixture. It has long been known that butadiene occurs in the various products obtained when oils are heated to a high temperature. Caventou first isolated butadiene in the form of its tetrabromide from illuminating gas, and Armstrong and Miller definitely established the presence of butadiene in the liquid obtained by compressing oil gas. The work of numerous later investigators has confirmed their results and has shown that the more drastic the heat treatment to which the oil is submitted the greater is the tendency for butadiene to be formed. For this reason vapor-phase cracking of petroleum, which is carried out at a much higher temperature than liquid-phase cracking, yields products specially rich in butadiene.

Calphad description of the Ge-Mn system

2014 ◽  
Vol 1642 ◽  
Author(s):  
Alexandre Berche ◽  
Jean-Claude Tédenac ◽  
Philippe Jund ◽  
Stéphane Gorsse
Keyword(s):  
Phase Diagram ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Critical Review ◽  
Thermodynamic Description ◽  
Calphad Method ◽  
Review Of The Literature ◽  
Solid Phases

ABSTRACTThe germanium-manganese system has been experimentally studied but no Calphad description is available yet. After a critical review of the literature concerning the phase diagram and the thermodynamic properties, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The liquid phase is described with an associated model and the variation to the stoichiometry of the solid phases is taken into account.

scholarly journals Efficient H2O2 generation and electro-Fenton degradation of pollutants in microchannels of oxidized monolithic-porous-carbon cathode

2019 ◽  
Vol 80 (5) ◽  
pp. 970-978
Author(s):  
Yunfei Guo ◽  
Shuai Wu ◽  
Hongtao Yu ◽  
Shuo Chen ◽  
Chunna Wang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Organic Pollutants ◽  
Porous Carbon ◽  
Hydraulic Retention Time ◽  
Fenton Process ◽  
Initial Concentration ◽  
H2o2 Generation ◽  
Flow Through ◽  
Fenton System ◽  
Degradation Of Pollutants

Abstract A monolithic-porous carbon (MPC) was fabricated by carbonizing a pine rod, and then the oxidized monolithic-porous carbon (O-MPC) was obtained via alkaline heat treatment of MPC. With well-ordered axial channels (diameters were 6–14 μm and 40–50 μm) and oxygen-containing functional groups, O-MPC as a flow-through cathode exhibited good capability in continuously generating H2O2 (422 μmol/L) via oxygen reduction. O-MPC and additional Fe2+ composed an electro-Fenton system and the performance of the system in degradation of organic pollutants was evaluated. For phenol, bisphenol A or sulfamethoxazole at initial concentration of 10 mg/L the removal efficiency reached 74%–82% in a hydraulic retention time of 100 seconds, nearly close to that of the homogeneous Fenton process (90%). This efficiency may be maintained for at least 10 hours, indicating a good stability of O-MPC. The results demonstrate the potential of O-MPC as a flow-through electrode to realize homogeneous-like degradation of organic pollutants in wastewater.

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