scholarly journals Comparison of Copper and Graphite Crucibles for Si Extraction from TiO2 - SiO2 System at Plasma-Arc Heating

2018 ◽  
Vol 5 (3) ◽  
pp. 128-130
Author(s):  
D. E. Kirpichev ◽  
A. A. Nikolaev ◽  
A. V. Nikolaev
Keyword(s):  
Temperature Field ◽  
Graphite Crucible ◽  
Arc Furnace ◽  
Plasma Arc ◽  
Dc Plasma ◽  
Sio2 System ◽  
Anode Spot ◽  
Arc Heating ◽  
Material Temperature ◽  
Made In

<p>Plasma arc recovery melting of the quartz-leucoxene concentrate is investigated. Experiments were made in laboratory DC plasma arc furnace in various crucibles. The best results are reached in a cold copper crucible. The temperature field of a pool is calculated in hot graphite and cold copper crucibles. It is shown that in a graphite crucible diameter of an anode spot is more, and density of current and material temperature in a spot is less, than in copper that is the reason of the worst refinements in a graphite crucible.</p>

Formation of plasma arc anode spot on the rotating graphite crucible

2020 ◽  
Vol 5 ◽  
pp. 24-32
Author(s):  
A.A. Nikolaev ◽  
◽  
A.V. Nikolaev ◽  
D.E. Kirpichyov ◽  
◽  
...  
Keyword(s):  
Argon Plasma ◽  
Graphite Crucible ◽  
Optical Pyrometer ◽  
Arc Furnace ◽  
Plasma Arc ◽  
Uniform Heating ◽  
Anode Spot ◽  
Arc Current ◽  
Diffuse Spot ◽  
Spot Formation

Formation of anode spots on rotating graphite crucible in the plasma arc furnace was investigated. The size and temperatures of the spots were determined by means of photographs and optical pyrometer. Composition of the plasma in anode spot region has been calculated. Cylindrical crucible of 100 mm in diameter with an axial hole of 40 mm in diameter and 28 mm in depth was rotated with the speed of ~100 rpm. Cylindrical cathode of 50 mm in diameter had an axial channel of 24 mm in diameter. Argon was fed through the channel as plasma forming gas. Crucible and cathode were located in the steel water cooled chamber with a volume of 150 liters. The arc was several centimeters long, arc current was 560-630 A. It was shown experimentally that 23-25 kW argon plasma arc can forms contracted or diffuse anode spot. The current density of contracted spot is 1800  A/cm2, while that of diffuse spot is ~250 A/cm2. Contracted spot formation occurs on a cold crucible and accompanied by intensive evaporation of graphite in a spot region. The carbon vapor decreased ionization potential of plasma near the anode and promoted contraction. A uniform heating of the hole in crucible up to 2700 K is needed for transformation of the contracted spot into diffuse one. Such heating was attained by rotation of crucible. Thermal isolation of crucible also promotes diffuse spot formation. Poisson’s equation was solved, and the voltage falls in space charge zones were calculated for contracted and diffuse spots as 10.7 and 1.5 V respectively. It was assumed that the lesser voltage fall promotes the diffuse spot formation.

Formation of Plasma Arc Anode Spot on the Rotating Graphite Crucible

2021 ◽  
Vol 12 (3) ◽  
pp. 643-649
Author(s):  
A. A. Nikolaev ◽  
A. V. Nikolaev ◽  
D. E. Kirpichyov
Keyword(s):  
Graphite Crucible ◽  
Plasma Arc ◽  
Anode Spot

Separation of titanium and silicon oxides during plasma-arc melting of quartz-leucoxene concentrate

2021 ◽  
Vol 5 ◽  
pp. 30-36
Author(s):  
A. A. Nikolaev ◽  
◽  
◽  
Keyword(s):  
Lower Layer ◽  
Energy Requirement ◽  
Graphite Crucible ◽  
Arc Furnace ◽  
Plasma Arc ◽  
Laboratory Plasma ◽  
Silicon Oxides ◽  
Arc Melting ◽  
Melting Separation ◽  
Oxide Particles

The aim of the work was investigation of separation of titanium’s and silicon’s oxides during plasma-arc melting of quartz-leucoxene concentrate from Yarega deposit. The melting was proceeded in laboratory plasma-arc furnace in graphite crucible at 16 – 40 kW of arc power. The microstructure and R-x phase analysis of solidified melt were investigated after arc melting. The melt separated on two layers. The upper layer consisted mainly of SiO2 in the form of glass, the lower layer — mainly of cemented titanium oxide particles ≈ 100 μm in dimension. TiO2, Ti8O15, Ti6O11, Fe3TiO3O10, Ti3O5 were observed. These particles formed during melting and moved throw liquid glass to the bottom of crucible with the speed of V ≈ 10–4 m/s. The separation of TiO2 and SiO2 required energy W ≈ 100 GJ/t of concentrate in laboratory plasma arc furnace. The possibility of industrial employment of the arc melting separation was discussed. The estimated energy requirement was about 5 GJ/t in 20-t arc furnace.

Research of a Plasma Arc Metal Surface Strengthening Robot

2012 ◽  
Vol 217-219 ◽  
pp. 1243-1246
Author(s):  
Tie Jun Zhao ◽  
Li Gang Tai
Keyword(s):  
Temperature Field ◽  
Heat Source ◽  
Metal Surface ◽  
High Frequency ◽  
Heating Process ◽  
Plasma Arc ◽  
Surface Strengthening ◽  
Arc Heating ◽  
Different Characteristics ◽  
Circular Heat

The technology of metal surface strengthening with plasma arc has quite different characteristics of High frequency quenching. The results similar to that of the laser beam. The properties make it possible that develop a plasma arc heating robot as a portable device for the case surface strengthening of steels. The characters of the plasma are analyzed at first, then the plasma arc as Guess distribution circular heat source is studied to create the surface strengthening temperature field and heating process. The surface strengthening technology and the hardware design of the plasma arc surface- strengthening robot is given.

Effect of Feed Forms on the Results of Melting of Fly Ash by a DC Plasma Arc Furnace

2009 ◽  
Vol 11 (5) ◽  
pp. 592-597 ◽  
Author(s):  
Chen Mingzhou ◽  
Meng Yuedong ◽  
Shi Jiabiao ◽  
Ni Guohua ◽  
Jiang Yiman ◽  
...  
Keyword(s):  
Fly Ash ◽  
Arc Furnace ◽  
Plasma Arc ◽  
Dc Plasma

Dc Plasma Arcs for Elemental Analysis

1977 ◽  
Vol 31 (4) ◽  
pp. 273-283 ◽  
Author(s):  
Christopher D. Keirs ◽  
Thomas J. Vickers
Keyword(s):  
Inductively Coupled Plasma ◽  
Plasma Jets ◽  
Local Thermal Equilibrium ◽  
Emission Spectrometry ◽  
Plasma Arc ◽  
Dc Plasma ◽  
Temperature Plasma ◽  
Inductively Coupled ◽  
Emission Limits ◽  
Made In

The development of plasma arc devices as replacements for chemical combustion flames in trace element analyses by emission spectrometry is traced with particular emphasis on those devices in which the spectrometric observation is made in the non-current-carrying portion of the discharge or “plume.” The question of local thermal equilibrium in both the arc column and plasma plume is discussed and the dependence of temperature on experimental variables is considered in terms of a model. In addition to the temperature attained, the performance of various gas stabilized arcs and plasma jets is discussed with reference to interferences, background emission, limits of detection, and precision. Particular attention is paid to the problem of sample aerosol introduction into the high temperature plasma. The dc plasma arc at its present level of development is compared with the inductively coupled plasma for use as a source in emission spectroscopy.

FEM Modeling and Validation of the Temperature Field in the Plasma Arc Bending of Laminated Clad Metal Sheets

2012 ◽  
Vol 602-604 ◽  
pp. 468-471
Author(s):  
Wen Qing Song ◽  
Jing Fu Chai ◽  
Wen Ji Xu
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Partial Melting ◽  
Energy Input ◽  
Mechanical Force ◽  
Plasma Arc ◽  
Fem Modeling ◽  
Temperature Variations ◽  
Preheating Temperature ◽  
Metal Sheets

Plasma arc bending of laminated clad metal sheets (LCMS) is a newly developed technique that produces deformation in the LCMS by thermal stress instead of external mechanical force. Since the temperature field leads to the thermal stress, a FEM mode was developed to study the temperature variations in the plasma arc bending of the LCMS which was validated robustness by the experiments. The results show that the temperature variations of the LCMS include the preheating, temperature dramatically changing and cooling stages. The lowest temperature is in the inlet whereas the highest temperature is in the outlet along the heating line. It needs to regulate the energy input of the plasma arc to avoid the possible partial melting of the LCMS.

scholarly journals COMPARISON OF RESULTS OBTAINED FROM TEMPERATURE MEASUREMENT AND NUMERICAL SIMULATION OF DC PLASMA ARC

1999 ◽  
Vol 48 (9) ◽  
pp. 1691
Author(s):  
SHAO QI-YUN ◽  
HE YU ◽  
GUO WEN-KANG ◽  
XU PING ◽  
ZANG DE-HONG
Keyword(s):  
Numerical Simulation ◽  
Temperature Measurement ◽  
Plasma Arc ◽  
Dc Plasma ◽  
Comparison Of Results
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