scholarly journals Selective Flotation of Pyrite from Arsenopyrite by Low Temperature Oxygen Plasma Pre-Treatment

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 568 ◽  
Author(s):  
Jincheng Ran ◽  
Xianyang Qiu ◽  
Zhen Hu ◽  
Quanjun Liu ◽  
Baoxu Song
Keyword(s):  
Low Temperature ◽  
Oxygen Plasma ◽  
Separation Efficiency ◽  
Plasma Modification ◽  
Xps Analysis ◽  
Pyrite Surface ◽  
Oxidation Degree ◽  
Selective Flotation ◽  
Icp Ms ◽  
Pre Treatment

In this study, the surface modification of arsenopyrite and pyrite with low temperature oxygen plasma was developed as an effective approach to improve the flotation separation efficiency of minerals. The micro-flotation experiments results indicated that plasma pre-treatment can achieve selective flotation of arsenopyrite from pyrite. The XPS analysis results indicated that the oxidation degree of plasma-modification arsenopyrite surface is much higher than that of pyrite. A large number of sulfide components on the surface of the mineral were oxidized to highly-valence hydrophilic oxides by plasma pre-treatment. ICP-MS analysis results revealed that the dissolution rate was determined by the oxidation degree of minerals and plasma modified accelerated the dissolution of arsenopyrite and pyrite. Zeta potential determination results confirmed that plasma can keep a relatively higher adsorption of SBX on the pyrite surface but inhibit the adsorption of collector onto the arsenopyrite surface.

Experimental Studies Concerning the Semipermeable Membrane Separation Efficiency for 134Cs, 137Cs, 57Co, 58Co, 60Co, 54Mn in Liquid Radioactive Waste I. Treatment of secondary waste from POD decontamination procedure

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Mirela Dulama ◽  
Nicoleta Deneanu ◽  
Cristian Dulama ◽  
Margarit Pavelescu
Keyword(s):  
Membrane Separation ◽  
Separation Efficiency ◽  
Liquid Radioactive Waste ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Suspended Solid ◽  
Process Efficiency ◽  
Active Charcoal ◽  
Precipitation Process ◽  
Pre Treatment

The paper presents the experimental tests concerning the treatment by membrane techniques of radioactive aqueous waste. Solutions, which have been treated by using the bench-scale installation, were radioactive simulated secondary wastes from the decontamination process with modified POD. Generally, an increasing of the retention is observed for most of the contaminants in the reverse osmosis experiments with pre-treatment steps. The main reason for taking a chemical treatment approach was to selectively remove soluble contaminants from the waste. In the optimization part of the precipitation step, several precipitation processes were compared. Based on this comparison, mixed [Fe(CN)6]4-/Al3+/Fe2+ was selected as a precipitation process applicable for precipitation of radionuclides and flocculation of suspended solid. Increased efficiencies for cesium radionuclides removal were obtained in natural zeolite adsorption pre-treatment stages and this was due to the fact that volcanic tuff used has a special affinity for this element. Usually, the addition of powdered active charcoal serves as an advanced purifying method used to remove organic compounds and residual radionuclides; thus by analyzing the experimental data (for POD wastes) one can observe a decreasing of about 50% for cobalt isotopes subsequently to the active charcoal adsorption.. The semipermeable membranes were used, which were prepared by the researchers from the Research Center for Macromolecular Materials and Membranes, Bucharest. The process efficiency was monitored by gamma spectrometry.

Low Temperature Silicon Oxidation With Electron Cyclotron Resonance Oxygen Plasma

1991 ◽  
Vol 235 ◽  
Author(s):  
K. T. Sung ◽  
S. W. Pang
Keyword(s):  
Low Temperature ◽  
Microwave Power ◽  
Cyclotron Resonance ◽  
Oxygen Plasma ◽  
Permanent Magnets ◽  
Electron Cyclotron Resonance ◽  
Electron Cyclotron ◽  
Rf Power ◽  
Source Distance ◽  
Ecr Source

ABSTRACTSilicon was oxidized at low temperature with an oxygen plasma generated by an electron cyclotron resonance (ECR) source. The ECR source utilized a multicusp magnetic field formed by permanent magnets. Microwave power at 2.45 GHz was applied to the source and if power at 13.56 MHz was applied to the sample stage. Si oxidation was studied as a function of source distance, pressure, microwave power, and rf power. The oxide thickness increases with microwave and rf power but decreases with source distance. The oxidation rate increases with pressure up to 12 mTorr, men decreases at higher pressure. The relative emission intensities in the plasma monitored using optical emission spectroscopy showed similar dependence on the source distance and microwave power. Oxidation temperature was estimated to be <100°C. Using ellipsometry and X-ray photoelectron spectroscopy, the oxidized films were found to be close to that of thermal oxide with refractive index at 1.45 and oxygen to silicon ratio of 2. From the current-voltage and capacitance-voltage measurements, the breakdown fields of these oxide films were 6.3 MV/cm and the fixed charge densities were 7×1010 cm−2.

Surface Interface Treatment of Conveyer Belt

2011 ◽  
Vol 332-334 ◽  
pp. 295-298
Author(s):  
Jia Huang Hu ◽  
Chiu Chun Lai ◽  
Wen Hao Hsing ◽  
Yi Kui Wang
Keyword(s):  
Adhesion Strength ◽  
Oxygen Plasma ◽  
High Strength ◽  
Far Infrared ◽  
Conveyor Belt ◽  
Polyester Fabric ◽  
Rubber Layer ◽  
Pet Fabric ◽  
Pre Treatment ◽  
Interface Treatment

This Research Is to Study the High Strength Polyester Fabric Pre-treatment by Oxygen Plasma and Far-infrared, in the Rfl Chemical Solid Composition and Methylenediphenylisocyanate Concentration of 4% for Adding. Analysis Adhesion Strength between Fabric to Fabric and Fabric to Rubber of the Conveyor Belt, and the Effect of Pet Fabric Mechanical Properties. from the Result, the Best Treatment Condition Is Oxygen Plasma Treated 1min 120w and Add 4% Methylenediphenylisocyanate(mdi). in the Adhesion Strength of Fabric and Fabric Layer Compared with the Untreated Has Raised up to 21.5kgf (25.0%), and Fabric and Rubber Layer Has Raised up to 23.7kgf (55.9%). Heating 20 Seconds, after Stop 10 Seconds and then Heat 20 Seconds and Add 4% Methylenediphenylisocyanate(mdi) Fabric-fabric Adhesion Strength Is 13.4 Kgf, Fabric-rubber Adhesion Strength Is 15.8 Kgf, Fabric-fabric and Fabric-rubber Adhesion Strength that Improve 24.1%, 43.6%.

Influence of Oxygen Plasma Modification Carbon Fiber on Flexural Strength and Hydrothermal Properties of CF/PES Composite

2014 ◽  
Vol 926-930 ◽  
pp. 141-144
Author(s):  
Xu Cui ◽  
Yan Jiao Huang ◽  
Yu Gao ◽  
Shuo Wang
Keyword(s):  
Composite Material ◽  
Carbon Fiber ◽  
Flexural Strength ◽  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Retention Rate ◽  
Test Method ◽  
Plasma Modification ◽  
Resin Matrix ◽  
Strength Retention

In this paper, low temperature oxygen plasma treatment method was adopted to process the carbon fiber surface. Flexural Strength test method was utilized to represent f composite material flexural strength. This paper observed flexural failure morphology of composite material by aid of SEM, then it compared the mechanical property, hygroscopicitiy and flexural strength retention rate of composite material before and after the plasma treatment. Results showed that the optimum treatment conditions of carbon fiber were 300W treatment power and 15-minute treatment time. Under the condition, the highest flexural strength value be increased by 19.55%.Saturated bibulous is low and bibulous rate is slow, flexural strength retention rate is 94.9%. And at the same time PES-C resin matrix can be strengthened, which will further improve the mechanical properties of composite materials.

Oxygen-plasma-assisted formaldehyde adsorption mechanism of SnO2 electrospun fibers

2021 ◽  
Author(s):  
Haiying Du ◽  
Yuxia Wu ◽  
Zhaorui Zhang ◽  
Wanmin He ◽  
Yanhui Sun ◽  
...  
Keyword(s):  
Oxygen Plasma ◽  
Adsorption Mechanism ◽  
Gas Sensing ◽  
High Energy ◽  
Plasma Modification ◽  
Electrospun Fibers ◽  
Chemisorbed Oxygen ◽  
Formaldehyde Sensing ◽  
Formaldehyde Adsorption ◽  
Sensing Performance

Abstract Abstract: Chemisorbed oxygen acts a crucial role in the redox reaction of semiconductor gas sensors, and which is of great significance for improving gas sensing performance. In this study, an oxygen-plasma-assisted technology is presented to enhance the chemisorbed oxygen for improving the formaldehyde sensing performance of SnO2 electropun fiber. An inductively coupled plasma device was used for oxygen plasma treatment of SnO2 electrospun fibers. The surface of SnO2 electrospun fibers was bombarded with high-energy oxygen plasma for facilitating the chemisorption of electronegative oxygen molecules on the SnO2 (110) surface to obtain an oxygen-rich structure. Oxygen-plasma-assisted SnO2 electrospun fibers exhibited excellent formaldehyde sensing performance. The formaldehyde adsorption mechanism of oxygen-rich SnO2 was investigated using density functional theory. After oxygen plasma modification, the adsorption energy and the charge transfer number of formaldehyde to SnO2 were increased significantly. And an unoccupied electronic state appeared in the SnO2 band structure, which could enhance the formaldehyde adsorption ability of SnO2. The gas sensing test revealed that plasma-treated SnO2 electrospun fibers exhibited excellent gas sensing properties to formaldehyde, low operating temperature, high response sensitivity, and considerable cross-selectivity. Thus, plasma modification is a simple and effective method to improve the gas sensing performance of sensors.

Sample pre-treatment techniques for use with ICP-MS hyphenated techniques for elemental speciation in biological samples

2017 ◽  
Vol 32 (1) ◽  
pp. 58-77 ◽  
Author(s):  
Han Wang ◽  
Xiaolan Liu ◽  
Kai Nan ◽  
Beibei Chen ◽  
Man He ◽  
...  
Keyword(s):  
Biological Samples ◽  
State Of The Art ◽  
Sample Pretreatment ◽  
The State ◽  
Elemental Speciation ◽  
Hyphenated Techniques ◽  
Treatment Techniques ◽  
Icp Ms ◽  
Pre Treatment

This review will focus specifically on the state of the art of novel sample pretreatment methods which have been combined with ICP-MS based hyphenated techniques for elemental speciation in biological samples.

Influence of Oxygen Plasma Modification on Surface Free Energy of PMMA Films and Cell Attachment

2008 ◽  
Vol 269 (1) ◽  
pp. 128-137 ◽  
Author(s):  
Canturk Ozcan ◽  
Pınar Zorlutuna ◽  
Vasıf Hasirci ◽  
Nesrin Hasirci
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Oxygen Plasma ◽  
Cell Attachment ◽  
Plasma Modification
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