scholarly journals Characterisation and Modelling of Gravity Pre-Concentration Amenability Using LST Fluidisation in a REFLUXTM Classifier

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 545
Author(s):  
Callan Lowes ◽  
James Zhou ◽  
Teresa McGrath ◽  
Jacques Eksteen ◽  
Kevin Galvin
Keyword(s):  
Particle Size ◽  
Environmental Risk ◽  
Lower Cost ◽  
Size Range ◽  
Continuous System ◽  
Chromite Ore ◽  
Density Distributions ◽  
Water Based ◽  
Inclined Channels ◽  
Partition Surface

Samples of the feed, underflow and overflow from water-based separations conducted using a continuous REFLUXTM Classifier involving inclined channels with a 3 mm spacing have been fractionated. Another REFLUXTM Classifier operating in a semi-batch configuration using a dense fluidising medium of lithium heteropolytungstates (LST) was used to determine the density distributions of the three streams. The partition surface of the separator was quantified, and the technique was validated against sink/float data for a −300 + 38 µm chromite ore separation. It was found that the LST flow fractionation determined the D50 with remarkable accuracy across the entire size range, with the Ep values also very good above 75 µm. For water-based continuous separations involving a gold ore covering the size range −1.0 + 0.090 mm, the D50 varied with particle size to the power −0.22 and the Ep remained relatively constant at approximately 170 kg/m3 for each of the narrow particle size ranges. These results were consistent with the partition surface validated based on the much finer size range of the higher density chromite ore. The performance of the continuous system was then modelled, with the results shown to agree well with separations conducted on the feed. This approach has been developed as an alternative to using the sink/float test, thus offering a new option with both a lower cost and minimal health and environmental risk. The findings from this study can in turn be used to assess the amenability of a given ore to gravity pre-concentration.

Transport Methods of Determining Particle Size Distributions in Colloidal Systems

1981 ◽  
Vol 54 (4) ◽  
pp. 882-891 ◽  
Author(s):  
C. D. Shuster ◽  
J. R. Schroeder ◽  
D. McIntyre
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Range ◽  
Size Distributions ◽  
Rotor Speed ◽  
Colloidal Systems ◽  
Particle Size Distributions ◽  
Density Distributions ◽  
Yield Information

Abstract The two techniques examined in this work yield information about the particle size distribution of the latexes studied. The ease of measurement is improved over previous methods used on broadly distributed latexes. The TPC curves for both the natural and synthetic latexes correlate with the centrifuge curves. Both techniques show the Hevea to have larger particles than the guayule. The techniques also show SBR latex samples 1 and 2 to have larger particles than samples 3 and 4. The TPC is useful only for particles between 0.3 µm and 20 µm in size. The centrifuge can be used for any size range of particles by altering the rotor speed or eluant density. By employing the proper mathematics, these data could be easily converted from optical density distributions to particle size distributions.

381. Sampling Efficiencies of Three Personal Aerosol Samplers within and Beyond the Inhalable Particle Size Range

2001 ◽  
Author(s):  
V. Aizenberg ◽  
P. Baron ◽  
K. Choe ◽  
S. Grinshpun ◽  
K. Willeke
Keyword(s):  
Particle Size ◽  
Size Range ◽  
Particle Size Range

Enrichment of a Nigerian chromite ore for metallurgical application by dense medium flotation and magnetic separation

2019 ◽  
Vol 116 (3) ◽  
pp. 324 ◽  
Author(s):  
Kuranga Ibrahim Ayinla ◽  
Alafara Abdullahi Baba ◽  
Bankim Chandra Tripathy ◽  
Malay Kumar Ghosh ◽  
Rajan Kumar Dwari ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Separation ◽  
Organic Liquid ◽  
Size Fraction ◽  
Dense Medium ◽  
Chromium Alloy ◽  
Magnetic Separator ◽  
Electro Deposition ◽  
Chromite Ore ◽  
Wet Chemical

This study, focused on the beneficiation of a Nigerian complex chromite ore sourced from Tunga-Kaduka, Anka Local Government of Zamfara State, Nigeria, assaying 45.85% Cr2O4 and 54.15% mineral impurities, was enriched concurrently through sink floatation and magnetic separation techniques. The chromite ore initially analyzed to contain silicate impurities was found not suitable for metallurgical purposes. Thus, enrichment was examined through gravity separation studies using organic liquid with different specific gravities at 2.8, 3.3, and 4.0. The separation of chromite ore with lowest particle size fraction was done using Mozley mineral separator followed by the magnetic separation of the sink product by magnetic separator. The results obtained revealed about 77% of the total material containing 300 μm particle size, 52% ˂ 212 μm and 17% below 75 μm. Subsequent analysis of the beneficiated ore was carried out by wet chemical analysis and atomic absorption spectrophotometer. The results showed that Cr2O4 content increased to 78.34% from initial 45.83% with maximum Cr:Fe ratio of 3.2:1, representing 84.27% of chromium metal present in the ore. The enrichment of Cr2O4 obtained in this study could be found metallurgically applicable in the electro-deposition and ferro-chromium alloy production practices.

Ultrafine particles in the cabin of a waiting commercial airliner at Tianjin International Airport, China

2017 ◽  
Vol 27 (9) ◽  
pp. 1247-1258 ◽  
Author(s):  
Jianlin Ren ◽  
Junjie Liu ◽  
Xiaodong Cao ◽  
Fei Li ◽  
Jianmin Li
Keyword(s):  
Particle Size ◽  
Ultrafine Particles ◽  
Size Range ◽  
Environmental Control ◽  
Particle Dynamic ◽  
Ground Vehicles ◽  
Flight Delays ◽  
Penetration Factor ◽  
International Airport ◽  
Outdoor Concentration

Passengers and crew on board of commercial airliners often spend extra time in the cabin waiting for departure due to flight delays. During the waiting period, a large amount of ambient ultrafine particles (UFPs) may penetrate into the aircraft cabin through the environmental control system (ECS) and ground air-conditioning cart (GAC). However, limited data are available for human exposure, in waiting commercial airliners, to freshly emitted UFPs from the exhaust of ground vehicles and airliners. To address this issue, we measured the ambient and in-cabin particle number concentrations and particle size distributions (PSDs) simultaneously in an MD-82 airliner parked at Tianjin International Airport, China. When air was supplied to the cabin by GAC, particle counts variation outdoors caused in-cabin variation with a 1–2 min delay. The in-cabin and ambient PSDs ranged from 15 to 600 nm were bimodal, with peaks at 30–40 and 70–90 nm. The GAC and ECS removed 1–73% particles in the size range of 15–100 nm and 30–47% in the size range of 100–600 nm. The relationship between the penetration factor and particle size was an inverted U-curve. An improved particle dynamic model from this study was used to calculate the time-dependent in-cabin UFPs concentrations with dramatic changes in outdoor concentration.

Synthesis of Emulsion for Water-Based Pigment Ink Jet

2011 ◽  
Vol 380 ◽  
pp. 81-84
Author(s):  
Li Ming Zhang ◽  
Xiu Lan Xin ◽  
Wei Jiang
Keyword(s):  
Particle Size ◽  
Water Resistance ◽  
Average Particle Size ◽  
Average Particle ◽  
Scanning Calorimetry ◽  
Reactive Surfactant ◽  
Potential Value ◽  
Ink Jet ◽  
Water Based ◽  
Pigment Ink

The water-based pigment ink jet emulsion whose particle size was less than 100nm was synthesized by the polymerization of methyl methacrylate, butyl acrylate and ethylhexyl acrylate, and anionic reactive surfactant and nonionic surfactant were used as the emulsifiers. The effects of particle size and water resistance were studied. The glass transition temperature was tested by differential scanning calorimetry. The average particle size of emulsion was range from 60nm to70nm, zeta potential value was less than -60mv; viscosity was 3.5mps; water absorption was 5.9%.

scholarly journals Particle size distribution and particle mass measurements at urban, near-city and rural level in the Copenhagen area and Southern Sweden

2003 ◽  
Vol 3 (6) ◽  
pp. 5513-5546 ◽  
Author(s):  
M. Ketzel ◽  
P. Wåhlin ◽  
A. Kristensson ◽  
E. Swietlicki ◽  
R. Berkowicz ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Number ◽  
Size Range ◽  
Urban Background ◽  
Total Particle ◽  
Urban Level ◽  
20 Nm ◽  
Traffic Source

Abstract. Particle size distribution (size-range 3–900 nm) and PM10 was measured simultaneously at an urban background station in Copenhagen, a near-city background and a rural location during a period in September-November 2002. The study investigates the contribution from urban versus regional sources of particle number and mass concentration. The total particle number (ToN) and NOx are well correlated at the urban and near-city level and show a distinct diurnal variation, indicating the common traffic source. The average ToN at the three stations differs by a factor of 3. The observed concentrations are 2500 # cm−3, 4500 # cm−3 and 7700 # cm−3 at rural, near-city and urban level, respectively. PM10 and total particle volume (ToV) are well correlated between the three different stations and show similar concentration levels, in average within 30% relative difference, indicating a common source from long-range transport that dominates the concentrations at all locations. Measures to reduce the local urban emissions of NOx and ToN are likely to affect both the street level and urban background concentrations, while for PM10 and ToV only measurable effects at the street level are probable. Taking into account the supposed stronger health effects of ultrafine particles reduction measures should address particle number emissions. The traffic source contributes strongest in the 10–200 nm particle size range. The maximum of the size distribution shifts from about 20–30 nm at kerbside to 50–60 nm at rural level. We also observe particle formation events in the 3–20 nm size range at rural location in the afternoon hours, mainly under conditions with low concentrations of pre-existing aerosol particles. The maximum in the size distribution of the "traffic contribution" seems to be shifted to about 28 nm in the urban location compared to 22 nm at kerbside. Assuming NOx as an inert tracer on urban scale let us estimate that ToN at urban level is reduced by 15–30% compared to kerbside. Particle removal processes, e.g. deposition and coagulation, which are most efficient for smallest particle sizes (<20 nm) and condensational growth are likely mechanisms for the loss of particle number and the shift in particle size.

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