Results of high-efficiency membrane pilot testing for membrane design optimisation

2021 ◽  
Vol 230 ◽  
pp. 25-32
Author(s):  
F.A. León ◽  
A. Ramos-Martín
Keyword(s):  
High Efficiency ◽  
Design Optimisation ◽  
Pilot Testing ◽  
Membrane Design

Laser-photometric lump separation of gold-bearing ore

2020 ◽  
pp. 16-22
Author(s):  
V. A. Rassulov ◽  
◽  
E. V. Nerushchenko ◽  
Keyword(s):  
High Efficiency ◽  
Separation Method ◽  
Separation Performance ◽  
Low Grade ◽  
Gold Content ◽  
High Grade ◽  
Pilot Testing ◽  
Ore Minerals ◽  
Concentrate Yield ◽  
Gold Bearing

This paper establishes the conditions for selecting the optimal lump separation method based on the values of indicator properties of the ore minerals and demonstrates respective pilot testing results for low-grade quartz-type sulfide gold-bearing ores. The studies have shown the high efficiency of laser-photometric processing of ores with low contents of finely disseminated ore components, for which other methods are ineffective. On the example of ore from the Natalka deposit, it has been shown that acceptable lump separation performance requires division of the original ore into high-grade balance ore (the separation of which would be impractical), low-grade balance ore (to be subjected to lump separation), and an off-balance mineralized mass. Lump processing remains efficient up to ore temperatures of minus 15 °C, if rinsed with 4 °C water. The following concentration indicators were achieved for the lean ore of the process sample taken from the Alternativny section at ore temperatures above minus 15 °С: with the concentrate yield of 20 to 28 %, the gold content increases by 3.0–4.5, with an average level of metal losses in the tailings of approximately 13 %. At ore temperatures down to minus 21 °C, when an opaque ice film with the thickness of over 1 mm is formed on the lump during its screening with washing, metal losses in the separation tailings become 2.0–2.5 times higher. The authors are grateful to the employees of TOMRA, CC of CJSC Polyus Zoloto, Natalka FMS department of OJSC RiM, and FSBI VIMS, who assisted in the pre-concentration technology testing for the ore of the Natalka deposit.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

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