Effect of microwave radiation on processing characteristics of sulphide minerals in inert atmosphere

2015 ◽  
Vol 51 (7) ◽  
pp. 1248-1258 ◽  
Author(s):  
N. Metin Can
Keyword(s):  
Microwave Radiation ◽  
Inert Atmosphere ◽  
Sulphide Minerals

scholarly journals A Mineralogical Investigation of Sintering in Cu-Rich Polymetallic Concentrates During Roasting in Inert Atmosphere

2020 ◽  
Vol 51 (4) ◽  
pp. 1446-1459 ◽  
Author(s):  
Pande Nishant Prasad ◽  
Andreas Lennartsson ◽  
Caisa Samuelsson
Keyword(s):  
Solid Solution ◽  
Inert Atmosphere ◽  
Oxidation Potential ◽  
Practical Relevance ◽  
Fundamental Study ◽  
Sulphide Minerals ◽  
System 2 ◽  
Sintering Mechanisms ◽  
Mineralogical Investigation ◽  
Impurity Elements

AbstractFour different Cu-rich polymetallic concentrates (additionally comprising Zn, Pb and impurity elements As, Sb) from various deposits in Sweden are examined, in particular for the sintering tendency during roasting in inert atmosphere. Experiments performed in a laboratory-scale roasting setup between 200 °C and 700 °C in intervals of 100 °C revealed that significant sintering initiates from 500 °C for all four concentrates. Two sintering mechanisms are determined from the examination of the sintered calcines: (1) solid-state assimilation of Cu-, Zn- and Fe-bearing main sulphide minerals to form a high-temperature solid solution, the iss phase belonging to the Cu-Fe-Zn-S system; (2) low-melting liquid phase formation due to partial melting of galena facilitated by the presence of impurity-bearing minerals, mainly the arsenopyrite and Sb sulphosalts such as tetrahedrite. Galena also forms a melt below 700 °C with the iss phase. Therefore, the presence of galena in polymetallic concentrates generally increases the susceptibility to early sintering. These experiments in inert atmosphere facilitate a fundamental study with practical relevance to the roasting in low oxidation potential environments, favourable for volatilization of impurity elements such as As and Sb.

Electron microscopy and diffraction studies of polyimides

1983 ◽  
Vol 41 ◽  
pp. 28-29
Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Structural Features ◽  
Inert Atmosphere ◽  
Polyimide Films ◽  
Resolution Electron ◽  
The Matrix ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Polymeric Samples

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.

A primate restraint chair for use in microwave radiation studies

1974 ◽  
Author(s):  
Vernon R. Reno ◽  
John O. de Lorge ◽  
George D. Prettyman ◽  
Clayton S. Ezell ◽  
Toby A. Griner
Keyword(s):  
Microwave Radiation

THERMAL ACTION OF MICROWAVE RADIATION ON A VERY THIN CONDUCTIVE FIBER

2018 ◽  
Vol 77 (19) ◽  
pp. 1719-1727
Author(s):  
N. G. Kokodiy ◽  
М. V. Kaydash ◽  
S. V. Pogorelov
Keyword(s):  
Microwave Radiation ◽  
Thermal Action ◽  
Conductive Fiber

Ability of Naphthoquinondiazide Photoresists to Exothermic Decomposition

2020 ◽  
pp. 90-96
Author(s):  
A.N. Shushpanov ◽  
◽  
A.Ya. Vasin ◽  
V.M. Raykova ◽  
G.G. Gadzhiev ◽  
...  
Keyword(s):  
Convective Heat Exchange ◽  
Inert Atmosphere ◽  
Necessary Condition ◽  
Critical Temperatures ◽  
Good Convergence ◽  
Measuring Devices ◽  
Explosive Transformation ◽  
Exothermic Decomposition ◽  
Experimental Approaches ◽  
Experimental Values

The article considers two intermediate products of positive photoresists (1,2-naphthoquinonediazide-(2)-5-sulfonic acid of monosodium salt — Dye M and 1,2-naphthoquinonediazide-(2)-5-sulfochloride — Dye N2) from the standpoint of the tendency to explosive transformation. The experimental values of flash points determined on the OTP setup were 130 °C for Dye M and 95 °C for Dye N2. These values are close to the temperatures of the beginning of intensive exothermic decomposition (132 and 111 °C, respectively) obtained by thermogravimetric analysis. In addition, this analysis showed the presence of exothermic peaks in the studied samples both in the air and in an inert atmosphere of helium, which is a necessary condition for the manifestation of a tendency to explosive transformation. To confirm the possibility of explosive transformation, the flash points of substances were also determined by the calculation method according to the formula, which is a consequence of the problem of thermal explosion during convective heat exchange with the environment, and gave a result close to the experimental one (the values were 138 and 105 °C, respectively). For this calculation the following was used: the kinetic parameters determined by the Kissinger method, the values of the density of substances determined on an automatic pycnometer, as well as the values of the heat of explosive transformation obtained with the help of the Real computer thermodynamic program. The research results confirming the tendency of the investigated compounds to explosive transformation, as well as the critical temperatures, exceeding which is unacceptable, were transferred to the production of FGUP GNTs NIOPIK to create a safe technological process, safe storage and transportation conditions. Considering the accuracy of the measuring devices, the process temperature should not exceed 125 °C for Dye M and 90 °C for Dye N2. The conducted studies and calculations show that the computational and experimental approaches have good convergence, give values in a close temperature range, and increase the reliability of the obtained results.

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