scholarly journals The Conversion of Calcium-Containing Phases and Their Separation with NaCl in Molten Salt Chlorinated Slags at High Temperature

2021 ◽  
Vol 14 (1) ◽  
pp. 293
Author(s):  
Feng Chen ◽  
Changlin Liu ◽  
Yuekai Wen ◽  
Fuxing Zhu ◽  
Hongguo Yao ◽  
...  
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Solid Phase ◽  
Removal Rate ◽  
Complex Compounds ◽  
Molar Ratio ◽  
Chlorination Process ◽  
N2 Atmosphere ◽  
Calcium Removal ◽  
Mg Content

The titanium resources in Panxi reign, China, have a high-impurities content of Ca and Mg, which is usually processed by the molten salt chlorination process. This process allows higher Ca and Mg content in its furnace burdens. However, there is a huge amount of molten salt chlorinated slag produced by this process, consisting of complex compounds and waste NaCl/KCl salts. These slags are always stockpiled without efficient utilization, causing serious environmental pollutions. To recycle the NaCl in the slag back to the molten salt chlorination process, a novel process to deal with those molten salt chlorinated slags with phase conversion at high temperature is presented in this paper. The calcium-containing solid phase was generated when Na2SiO3 was added to the molten salt chlorinated slags at high temperature, while NaCl was kept as a liquid. Thus, liquid NaCl was easily separated from the calcium-containing solid phase, and it could be reused in the molten salt chlorination process. The conversion of calcium-containing phases and their separation of NaCl are the key parts of this work, and they have been systematically studied in this paper; thermodynamic analysis, phase transformation behavior, and calcium removal behavior have all been investigated. The calcium removal rate is 78.69% when the molar ratio of CaCl2:Na2SiO3 is 1:1.5 at 1173 K and N2 atmosphere.

scholarly journals Study on the Synergistic Extraction of Lithium from Spent Lithium Cobalt Oxide Batteries by Molten Salt Electrolysis and Two-Step Precipitation Method

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1163
Author(s):  
Hui Li ◽  
Haotian Li ◽  
Jinglong Liang ◽  
Hongyan Yan ◽  
Zongying Cai
Keyword(s):  
Oxalic Acid ◽  
Molten Salt ◽  
Ph Value ◽  
Initial Conditions ◽  
Removal Rate ◽  
Lithium Ion ◽  
Spherical Particles ◽  
Precipitation Method ◽  
Molten Salt Electrolysis ◽  
Calcium Removal

With the continuous development of society, the number of spent lithium-ion batteries has also increased, and the recovery of valuable metals such as Ni, Co, and Li has become the main research direction of many scholars. In this paper, the extraction process of lithium that enters the molten salt after LiCoO2 electrolysis is studied. Oxalic acid and phosphate are added to molten salt containing lithium ions to realize the two-part precipitation method to extract lithium. The influence of pH value, temperature, reaction time, and oxalic acid (or phosphate) addition on the process of oxalic acid calcium removal and phosphate lithium precipitation is analyzed. The results show that the calcium removal rate of oxalic acid has reached 99.72% (Initial conditions: PH = 7.0, T = 70 °C, t = 1.5 h, n(H2C2O4):n(Ca2+) = 1.2:1). The precipitation of Li3PO4 obtained in the phosphate extraction experiment of lithium is as high as 88.44% (Initial conditions: PH = 8.0, T = 70 °C, t = 1.5 h, n(actual dosage of Na3PO4):n(theoretical dosage of Na3PO4) = 1.2:1). The obtained lithium phosphate crystals show regular spherical particles, which can be seen by SEM.

scholarly journals Reactive plasma cleaning and restoration of transition metal dichalcogenide monolayers

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Daniil Marinov ◽  
Jean-François de Marneffe ◽  
Quentin Smets ◽  
Goutham Arutchelvan ◽  
Kristof M. Bal ◽  
...  
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Field Effect Transistors ◽  
Removal Rate ◽  
2D Materials ◽  
Scale Up ◽  
Transition Metal Dichalcogenides ◽  
Chemical Properties ◽  
Plasma Cleaning ◽  
Transition Metal Dichalcogenide

AbstractThe cleaning of two-dimensional (2D) materials is an essential step in the fabrication of future devices, leveraging their unique physical, optical, and chemical properties. Part of these emerging 2D materials are transition metal dichalcogenides (TMDs). So far there is limited understanding of the cleaning of “monolayer” TMD materials. In this study, we report on the use of downstream H2 plasma to clean the surface of monolayer WS2 grown by MOCVD. We demonstrate that high-temperature processing is essential, allowing to maximize the removal rate of polymers and to mitigate damage caused to the WS2 in the form of sulfur vacancies. We show that low temperature in situ carbonyl sulfide (OCS) soak is an efficient way to resulfurize the material, besides high-temperature H2S annealing. The cleaning processes and mechanisms elucidated in this work are tested on back-gated field-effect transistors, confirming that transport properties of WS2 devices can be maintained by the combination of H2 plasma cleaning and OCS restoration. The low-damage plasma cleaning based on H2 and OCS is very reproducible, fast (completed in a few minutes) and uses a 300 mm industrial plasma etch system qualified for standard semiconductor pilot production. This process is, therefore, expected to enable the industrial scale-up of 2D-based devices, co-integrated with silicon technology.

scholarly journals Adsorption of copper ions on Magnolia officinalis residues after solid-phase fermentation with Phanerochaete chrysosporium

2019 ◽  
Vol 17 (1) ◽  
pp. 1173-1184 ◽  
Author(s):  
Fengyun Tao ◽  
Yangping Liu ◽  
Junliang Chen ◽  
Peng Wang ◽  
Qing Huo
Keyword(s):  
Chinese Medicine ◽  
Phanerochaete Chrysosporium ◽  
Solid Phase ◽  
Copper Ions ◽  
Removal Rate ◽  
Low Cost ◽  
Preparation Technique ◽  
Adsorption Enthalpy ◽  
Pseudo Second Order ◽  
Magnolia Officinalis

AbstractThe disposal of residues while manufacturing Chinese medicine has always been an issue that concerns pharmaceutical factories. Phanerochaete chrysosporium was inoculated into the residues of Magnolia officinalis for solid-phase fermentation to enzymatically hydrolyze the lignin in the residues and thus to improve the efficiency of removal of the copper ions from residues for the utilization of residues from Chinese medicine. With the increase in activities of lignin-degrading enzymes, especially during the fermentation days 6 to 9, the removal rate of copper ions using M. officinalis residues increased dramatically. The rate of removal reached the maximum on the 14th day and was 3.15 times higher than the initial value. The rate of adsorption of copper ions on the fermentation-modified M. officinalis residues followed the pseudo-second-order kinetics. The adsorption isotherms were consistent with the Freundlich models. The adsorption enthalpy was positive, indicating that it was endothermic and elevation in temperature was favorable to this adsorption process. The adsorption free energy was negative, implying the spontaneity of the process. The copper ions adsorbed could be effectively recovered using 0.2 M hydrochloric acid solution. After five successive cycles of adsorption-regeneration, the fermentation-modified M. officinalis residues exhibited a stable adsorption capacity and greater reusability. The M. officinalis residues fermented with P. chrysosporium are low-cost and environmentally friendly copper ions adsorbent, and this preparation technique realizes the optimum utilization of Chinese medicine residues.

Absorption and Stripping of CO2 with a Molten Salt Slurry in a Bubble Column at High Temperature

2006 ◽  
Vol 29 (9) ◽  
pp. 1118-1121 ◽  
Author(s):  
K. Terasaka ◽  
Y. Suyama ◽  
K. Nakagawa ◽  
M. Kato ◽  
K. Essaki
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Bubble Column

Electrochemical Studies on High-Temperature Corrosion of Silicon-Iron Coatings and Iron Aluminide Intermetallic Alloys by Molten Salts

CORROSION ◽  
2001 ◽  
Vol 57 (6) ◽  
pp. 489-496 ◽  
Author(s):  
M. Amaya ◽  
J. Porcayo-Calderon ◽  
L. Martinez
Keyword(s):  
High Temperature ◽  
Molten Salt ◽  
Electric Power ◽  
Molten Salts ◽  
Corrosion Current ◽  
High Temperature Corrosion ◽  
Iron Aluminide ◽  
Fuel Oil ◽  
Silicon Iron ◽  
Salt Corrosion

Abstract The performance of Fe-Si coatings and an iron aluminide (FeAl) intermetallic alloy (FeAl40at%+0.1at%B+10vol%Al2O3) in molten salts containing vanadium pentoxide (V2O5) and sodium sulfate (Na2SO4) is reported. Corrosion and fouling by ash deposits containing V2O5 and Na2SO4 are typical corrosion problems in fuel oil-fired electric power units. High-temperature corrosion tests were performed using both electrochemical polarization and immersion techniques. The temperature interval of this study was 600°C to 900°C, and the molten salts were 80wt%V2O5-20wt%Na2SO4. Curves of corrosion current density vs temperature obtained by the potentiodynamic studies are reported, as well as the weight loss vs temperature curves from molten salt immersion tests. Both Fe-Si coatings and FeAl40at%+0.1at%B+10vol%Al2O3 showed good behavior against molten salt corrosion. The final results show the potential of these coatings and alloys to solve the high-temperature corrosion in fuel oil-fired electric power units.

In Situ High-Temperature Transmission Electron Microscopy Observations of the Formation of Nanocrystalline TiC from Nanocrystalline Anatase (TiO2)

1998 ◽  
Vol 4 (3) ◽  
pp. 269-277 ◽  
Author(s):  
A. Agrawal ◽  
J. Cizeron ◽  
V.L. Colvin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Solid Phase ◽  
Anatase Phase ◽  
High Resolution Electron Microscopy ◽  
Rutile Phase ◽  
Transmission Electron ◽  
New Phase

In this work, the high-temperature behavior of nanocrystalline TiO2 is studied using in situ transmission electron microscopy (TEM). These nanoparticles are made using wet chemical techniques that generate the anatase phase of TiO2 with average grain sizes of 6 nm. X-ray diffraction studies of nanophase TiO2 indicate the material undergoes a solid-solid phase transformation to the stable rutile phase between 600° and 900°C. This phase transition is not observed in the TEM samples, which remain anatase up to temperatures as high as 1000°C. Above 1000°C, nanoparticles become mobile on the amorphous carbon grid and by 1300°C, all anatase diffraction is lost and larger (50 nm) single crystals of a new phase are present. This new phase is identified as TiC both from high-resolution electron microscopy after heat treatment and electron diffraction collected during in situ heating experiments. Video images of the particle motion in situ show the nanoparticles diffusing and interacting with the underlying grid material as the reaction from TiO2 to TiC proceeds.

Influence of Mg on Resistivity, Adhesion, Agglomeration of Ag(Mg)/SiO2/Si Multilayers

2001 ◽  
Vol 686 ◽  
Author(s):  
Bongjoo Kang ◽  
Heejung Yang ◽  
Sungjin Hong ◽  
Yeonkyu Ko ◽  
Chang-Oh Jeong ◽  
...  
Keyword(s):  
High Temperature ◽  
Annealing Temperature ◽  
Enhanced Resistance ◽  
Free Silicon ◽  
Mg Content ◽  
Mgo Layers

AbstractThe effect of Mg in Ag(Mg)/SiO2/Si multilayers on adhesion, agglomeration, and resistivity after annealing in vacuum at 200 to 500 have been investigated. The annealing of Ag(Mg)/SiO2/Si multilayers produced surface and interfacial MgO layers, resulting in MgO/Ag(Mg)/MgO/SiO2/Si structure. The presence of surface MgO provided the passivation against air, thus leading to the significantly enhanced resistance to agglomeration. In addition, the resistivity of Ag(Mg) film decreased by lowering Mg content and increasing the annealing temperature as well. Furthermore, Ag adhesion to SiO2 was improved due to the formation of the interfacial MgO layer resulting from the reaction of segregated Mg with SiO2. Also, the negligible solubility of Si in Ag prevented the dissolution of free silicon produced from the reaction, Mg + SiO2 = MgO + Si, which was in contrast with the dissolution of a significant amount of silicon released from the SiO2 substrate in Cu(Mg)/SiO2/Si multilayers after annealing at high temperature, e.g., 400. The dissolved Si in Cu caused the rapid increase in resistivity in Cu(Mg)/SiO2/Si.

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