Recovery of platinum using magnesium vapor

2003 ◽  
Vol 18 (8) ◽  
pp. 1960-1967 ◽  
Author(s):  
Toru H. Okabe ◽  
Sachiko Yamamoto ◽  
Yoshihiro Kayanuma ◽  
Masafumi Maedaaff
Keyword(s):  
Room Temperature ◽  
Precious Metals ◽  
Extraction Process ◽  
Alloy Formation ◽  
Magnesium Vapor ◽  
Aqua Regia ◽  
Pure Platinum ◽  
Pt Alloy ◽  
Leaching Solution ◽  
Vapor Treatment

To develop an effective process for the recovery of precious metals from scrap, we investigated a new platinum extraction process using alloy formation by magnesium vapor and successive leaching with an aqueous solution. Pure platinum plates were reacted with magnesium vapor at constant temperatures ranging between 873 and 1173 K for 3 h, and Mg–Pt alloy samples were synthesized. The obtained Mg–Pt alloy was then dissolved in aqua regia or in an aqueous HCl solution at room temperature. Platinum was recovered from the leaching solution by conventional precipitation technique, and the platinum obtained by each process was analyzed chemically. It was found that 94% of the platinum was recovered by this process. After Mg vapor treatment, 100% of the platinum was dissolved when kept in aqua regia for 1 h, whereas only 25% of untreated pure platinum was dissolved when kept in aqua regia for 4 h.

scholarly journals Longevity of Raw and Lyophilized Crude Urease Extracts

2021 ◽  
Vol 2 (2) ◽  
pp. 325-334
Author(s):  
Neda Javadi ◽  
Hamed Khodadadi Tirkolaei ◽  
Nasser Hamdan ◽  
Edward Kavazanjian
Keyword(s):  
Crude Extract ◽  
Room Temperature ◽  
Low Cost ◽  
Extraction Process ◽  
Crude Extracts ◽  
Simple Extraction ◽  
Commercial Applications ◽  
Stable Source ◽  
The Stability ◽  
The Cost

The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.

Zinc carbonate recovery from brass melting slag

2021 ◽  
Vol 98 ◽  
pp. 14-18
Author(s):  
Thao Nguyen Thi ◽  
◽  
Nam Pham Ky ◽  
Ngoc Tran Vu Diem
Keyword(s):  
Sulfuric Acid ◽  
High Purity ◽  
Room Temperature ◽  
Ph Value ◽  
Zinc Carbonate ◽  
Leaching Solution ◽  
Optimized Conditions ◽  
Melting Slag

Brass melting slag (20.38 wt.% Zn) was leached in sulfuric acid with concentration of (50 + 80) g/l H2SO4, leaching temperature of (30 + 60) °C for (30 + 120) min. The optimized conditions for 94.16% Zn extraction from brass melting slag were found as 70 g/l H2SO4, room temperature and 90 min. The leaching solution was purified by removal of Fe through Fe(OH)3 precipitation when adding ZnO to adjust pH value of 5. The solution was continuously cemented by Zn metal at 60 °C for 60 min to obtain Cu metal with high purity of 99 wt.% Cu. The purified solution with 37.64 g/l Zn was modified by Na2C03 to have pH value of about 6 and precipitation of ZnC03 (94.14 %).

scholarly journals Micro-crystalline structure of platinum

1902 ◽  
Vol 69 (451-458) ◽  
pp. 433-435
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Crystalline Structure ◽  
Aqua Regia ◽  
Pure Platinum ◽  
Small Ingot

The crystalline structure of platinum does not appear to have been studied, although it forms an interesting subject for investigation. A small ingot of pure platinum was obtained for the experiments. A section was cut therefrom and machined to 5/16 inch square and 1/10 inch in thickness. The section was then carefully polished and etched in aqua regia of the following strength :— 4 parts of hydrochloric acid (sp. gr. 1·2). 1 part of nitric acid (sp. gr. 1·42).

Enhanced coercivity of HCP Co–Pt alloy thin films on a glass substrate at room temperature for patterned media

2015 ◽  
Vol 391 ◽  
pp. 12-16 ◽  
Author(s):  
Y.S. Chen ◽  
An-Cheng Sun ◽  
H.Y. Lee ◽  
Hsi-Chuan Lu ◽  
Sea-Fue Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Glass Substrate ◽  
Room Temperature ◽  
Patterned Media ◽  
Pt Alloy

Possible Applications of Nanomaterials for Nuclear Fusion Devices

2018 ◽  
Vol 5 (1-2) ◽  
pp. 11-27 ◽  
Author(s):  
Takeo Oku
Keyword(s):  
Hydrogen Storage ◽  
Heavy Ions ◽  
Room Temperature ◽  
Nuclear Fusion ◽  
Alloy Formation ◽  
Muon Catalyzed Fusion ◽  
Energy Materials ◽  
Plasma Facing Components ◽  
Key Points ◽  
Diffusion Calculation

Abstract Conditions of nuclear fusion and nuclear fusion devices were described, and some possible applications of nanomaterials for nuclear fusion devices were presented in the present article. Muon-catalyzed fusion is one of methods for nuclear fusion to cause even at room temperature or lower, and protons or heavy ions with huge energy are irradiated to metals such as beryllium or copper, which results in emission of negative or positive charged muons from the metals. An experiment using a pyroelectric power source using lithium tantalite crystal was also reported to achieve nuclear fusion in a desktop-like device. Hydrogen storage is also important for the fusion devices, and the possibility of hydrogen storage in hydrogen storage metallic alloys was studied by diffusion calculation and potential calculation of deuterium fusion. Enhancement of deuterium diffusion in the Pd alloys would be one of the key points for energy materials. Carbon(C)/copper(Cu)-based composite materials with high thermal conductivity and good stability at high temperatures were also developed by adding a small amount of titanium, which has a low enthalpy of alloy formation with C and Cu. These carbon-based materials could be a candidate material for the plasma facing components of fusion devices.

scholarly journals Kinetics of scandium recovery by TVEX-TBP from the solution formed after the salt chlorinator cake leaching

2020 ◽  
Vol 168 ◽  
pp. 00050
Author(s):  
Vadym Korovin ◽  
Yurii Pohorielov ◽  
Yurii Shestak ◽  
Oleksandr Valiaiev ◽  
Jose Luis Cortina
Keyword(s):  
Chemical Interaction ◽  
Extraction Process ◽  
Second Order ◽  
Order Kinetic ◽  
Order Model ◽  
Elovich Equation ◽  
Diffusion Phase ◽  
Leaching Solution ◽  
Pseudo Second Order ◽  
Kinetics Of

Kinetics of scandium recovery by TVEX containing tributyl phosphate was studied from the clarified leaching solution of salt chlorinator cake. To assess the contribution of each diffusion phase, experimental data were analyzed using a graphic method. To define the contribution of chemical interaction into the scandium extraction process, recovery kinetics was quantitatively described using pseudo-first order, pseudo-second order kinetic models and Elovich equation in linearized form. It was established that recovery kinetics was most accurately described with the pseudo-second-order model.

scholarly journals Silicon Carbide BJT Oscillator Design Using S-Parameters

2019 ◽  
Vol 963 ◽  
pp. 674-678
Author(s):  
Muhammad Waqar Hussain ◽  
Hossein Elahipanah ◽  
Saul Rodriguez ◽  
Bengt Gunnar Malm ◽  
Ana Rusu
Keyword(s):  
Room Temperature ◽  
Design Method ◽  
Model Fitting ◽  
Simulation Models ◽  
Parameter Extraction ◽  
Extraction Process ◽  
Large Signal ◽  
S Parameter ◽  
Wafer Probing ◽  
Modelling Effort

Radio frequency (RF) oscillator design typically requires large-signal, high-frequency simulation models for the transistors. The development of such models is generally difficult and time consuming due to a large number of measurements needed for parameter extraction. The situation is further aggravated as the parameter extraction process has to be repeated at multiple temperature points in order to design a wide-temperature range oscillator. To circumvent this modelling effort, an alternative small-signal, S-parameter based design method can be employed directly without going into complex parameter extraction and model fitting process. This method is demonstrated through design and prototyping a 58 MHz, high-temperature (HT) oscillator, based on an in-house 4H-SiC BJT. The BJT at elevated temperature (up to 300 0C) was accessed by on-wafer probing and connected by RF-cables to the rest of circuit passives, which were kept at room temperature (RT).

Ethanol vapor treatment inhibits apple ripening at room temperature even with the presence of ethylene

2021 ◽  
Vol 173 ◽  
pp. 111415
Author(s):  
Fabio Rodrigo Thewes ◽  
Basem Mahmoud Balkees ◽  
Felix Büchele ◽  
Jens Norbert Wünsche ◽  
Daniel Alexandre Neuwald ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ethanol Vapor ◽  
Apple Ripening ◽  
Vapor Treatment

Recovery of nanosize zinc from phosphor wastes with an ionic liquid

2009 ◽  
Vol 6 (3) ◽  
pp. 268 ◽  
Author(s):  
Hsin-Liang Huang ◽  
H. Paul Wang ◽  
Edward M. Eyring ◽  
Juu-En Chang
Keyword(s):  
Ionic Liquid ◽  
Absorption Spectroscopy ◽  
Room Temperature ◽  
Bond Distance ◽  
Extraction Process ◽  
Room Temperature Ionic Liquid ◽  
Zns Nanoparticles ◽  
Recovery Method ◽  
X Ray ◽  
X Ray Absorption

Environmental context. Very fine phosphor ashes are discharged from particulate collection systems (such as bag houses) in the cathode ray tube or television disassembling processes. Effective recovery of ZnO and ZnS nanoparticles from the phosphor ash can be achieved by extraction with a room temperature ionic liquid. By synchrotron radiation X-ray absorption spectroscopy, the obtained molecular scale data turn out to be very useful in revealing speciation of zinc in the extraction process, which also facilitates the development of a simple nanoparticle recovery method. Abstract. An effective, simple method has been developed for the recovery of ZnO and ZnS nanoparticles from hazardous phosphor ash waste. Experimentally, zinc (77%) in the phosphor ash (that contains mainly zinc (91%)) can be recovered by extraction with a room temperature ionic liquid (RTIL) ([C4mim][PF6], 1-butyl-3-methylimidazolium hexafluorophosphate). Component fitted X-ray absorption near edge structure (XANES) spectra of zinc indicate that metallic zinc (Zn) (9%) in the phosphor ash can be dissolved to form a Zn2+–1-methylimidazole ([mim]) complex during extraction with the RTIL. ZnS and ZnO nanoparticles (60–61%) can also be extracted from the phosphor. Over the 298–523 K temperature range, desired ZnO/ZnS ratios (0.3–0.6) can be obtained since interconversion of ZnS to ZnO in the RTIL is temperature dependent. The Fourier transformed extended X-ray absorption fine structure (EXAFS) data also show that the nanosize ZnS extracted in the RTIL possesses a Zn–S bond distance of 2.33 Å with coordination numbers (CNs) of 3.6–3.7. At 523 K, in the RTIL, ~30% of the ZnS is oxidised to form octahedral ZnO (with a bond distance of 2.10 Å and a CN of 6.1) that may coat the surfaces of the ZnS nanoparticles. This work exemplifies the utilisation of X-ray absorption spectroscopy (EXAFS and XANES) to reveal speciation and possible reaction pathways in a nanoparticle extraction process (with a RTIL) in detail.

Promotion of performances of quantum dot solar cell and its tandem solar cell with low bandgap polymer (PTB7-Th):PC71BM by water vapor treatment on quantum dot layer on its surface

2017 ◽  
Vol 5 (40) ◽  
pp. 21528-21535 ◽  
Author(s):  
Yi-Lun Li ◽  
Po-Nan Yeh ◽  
Sunil Sharma ◽  
Show-An Chen
Keyword(s):  
Solar Cell ◽  
Water Vapor ◽  
Quantum Dot ◽  
Room Temperature ◽  
Layer Surface ◽  
Tandem Solar Cell ◽  
Low Bandgap ◽  
New Treatments ◽  
Vapor Treatment ◽  
Pbs Quantum Dot

In this study, we propose new treatments on the PbS quantum dot (QD) layer surface by exposing it to air, water vapor and oxygen environments at room temperature.

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