Fine fraction loss process in the production of instantized products

Aerosol samples were collected in Phoenix, Arizona on eleven dates between July 1989 and April 1990. Elemental compositions were determined for approximately 1000 particles per sample using an electron microprobe with an energy-dispersive x-ray spectrometer. Fine-fraction samples (particle cut size of 1 to 2 μm) were analyzed for each date; coarse-fraction samples were also analyzed for four of the dates.The data were reduced using multivariate statistical methods. Cluster analysis was first used to define 35 particle types. 81% of all fine-fraction particles and 84% of the coarse-fraction particles were assigned to these types, which include mineral, metal-rich, sulfur-rich, and salt categories. "Zero-count" particles, consisting entirely of elements lighter than Na, constitute an additional category and dominate the fine fraction, reflecting the importance of anthropogenic air pollutants such as those emitted by motor vehicles. Si- and Ca-rich mineral particles dominate the coarse fraction and are also numerous in the fine fraction.

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Monitoring of environmental effects and process performance during biological treatment of sediment from the petroleum Harbour in Amsterdam

Water Science & Technology ◽

10.2166/wst.1998.0777 ◽

1998 ◽

Vol 37 (6-7) ◽

pp. 395-402

Author(s):

Guus C. Stefess

Keyword(s):

Environmental Effects ◽

Organic Contaminants ◽

Biological Treatment ◽

Biological Process ◽

Froth Flotation ◽

Fine Fraction ◽

Dry Weight ◽

Pilot Project ◽

Mineral Oil ◽

Silt Fraction

A full-scale (470 m3) process for biological treatment of dredging spoil from the Petroleum Harbour in Amsterdam has been monitored during a pilot project. The dredging spoil was heavily polluted with polycyclic aromatic hydrocarbons (PAH) and mineral oil. The remediation chain involved dredging, transport of dredged spoil, hydrocyclone separation, froth flotation of the coarse particles, and biological treatment of the silt fraction (<20 μm) in stirred bioractors. The independent monitoring was aimed at recording the environmental effects, product quality and performance of the biological process. Hydrocyclone separation (cut point 20 m) resulted in two bulk streams: 65% sand and 30% silt (based on total dry weight of the input). The sand was cleaned and could be reused as building material. PAH and mineral oil were successfully concentrated in the silt fraction (<20 μm), which was treated biologically. Biological treatment during continuous feeding of fine fraction, at a residence time of 8-10 days for the entire bioreactor system, resulted in considerably reduced mineral oil and PAH contents. Furthermore, the leaching of organic contaminants was reduced, as well as the ecotoxicity. The obtained silt product however did not meet the demands, and had to be landfilled. Minor emissions of contaminants were measured in wastewater and offgas. The energy and chemicals consumption were acceptable. The biological process appears to be promising for the treatment of less-severely contaminated dredged material.

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Non-variable horizontal-branch stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900116894 ◽

1997 ◽

Vol 189 ◽

pp. 363-368

Author(s):

Robert T. Rood

Keyword(s):

Mass Loss ◽

Physical Basis ◽

Horizontal Branch ◽

Loss Process ◽

Horizontal Branch Stars ◽

Theoretical Results ◽

Branch Morphology

For 25 years our ignorance of the physical basis of this mass loss process has been the barrier to progress in understanding horizontal branch morphology. I review some recent observational and theoretical results which may be giving us clues about the nature of the mass loss process.

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Quantitative analysis of fine dust particles on moss surfaces under laboratory conditions using the example of Brachythecium rutabulum

Environmental Science and Pollution Research ◽

10.1007/s11356-021-14218-5 ◽

2021 ◽

Author(s):

Bilitis Désirée Vanicela ◽

Martin Nebel ◽

Marielle Stephan ◽

Christoph Riethmüller ◽

Götz Theo Gresser

Keyword(s):

Fine Fraction ◽

Model Organism ◽

Dust Particles ◽

Quantitative Detection ◽

Suitable Model ◽

Fine Dust ◽

Sem Images ◽

Moss Species ◽

Laboratory Conditions ◽

Number Of Particles

AbstractThe identification of a model organism for investigations of fine dust deposits on moss leaflets was presented. An optical method with SEM enabled the quantitative detection of fine dust particles in two orders of magnitude. Selection criteria were developed with which further moss species can be identified in order to quantify the number of fine dust particles on moss surfaces using the presented method. Among the five moss species examined, B. rutabulum had proven to be the most suitable model organism for the method presented here. The number of fine dust particles on the moss surface of B. rutabulum was documented during 4 weeks of cultivation in the laboratory using SEM images and a counting method. The fine dust particles were recorded in the order of 10 μm–0.3 μm, divided into two size classes and counted. Under laboratory conditions, the number of particles of the fine fraction 2.4 μm–0.3 μm decreased significantly.

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Investigation of the Formation Mechanism and Environmental Risk of Tire—Pavement Wearing Waste (TPWW)

Sustainability ◽

10.3390/su13158172 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8172

Author(s):

Kechen Wang ◽

Xiangyu Chu ◽

Jiao Lin ◽

Qilin Yang ◽

Zepeng Fan ◽

...

Keyword(s):

Formation Mechanism ◽

Organic Contaminants ◽

Asphalt Mixture ◽

Fine Fraction ◽

Crumb Rubber ◽

Environmental Benefit ◽

The Road ◽

Open Graded Friction Course ◽

Volatile Alkanes ◽

Physical And Chemical

Tire—pavement interaction behaviours result in large amounts of wearing waste matter, which attaches to the surface of the pavement and is directly exposed to the surrounding environment. This kind of matter imposes a great challenge to the environment of the road area. The current study is devoted to carrying out a comprehensive investigation of the formation mechanism of tire—pavement wearing waste (TPWW), as well as the resulting environmental risks. A self-developed piece of accelerated polishing equipment, the Harbin advanced polishing machine (HAPM), was employed to simulate the wearing process between vehicle tires and pavement surfaces, and the TPWW was collected to conduct morphological, physical, and chemical characterisations. The results from this study show that the production rate of TPWW decreases with the increase in polishing duration, and the coarse particles (diameters greater than 0.425 mm) account for most of the TPWW obtained. The fine fraction (diameter smaller than 0.425 mm) of the TPWW comprises variously sized and irregularly shaped rubber particles from the tire, as well as uniformly sized and angular fine aggregates. The environmental analysis results show that volatile alkanes (C9–C16) are the major organic contaminants in TPWW. The Open-Graded Friction Course (OGFC) asphalt mixture containing crumb rubber as a modifier showed the highest risk of heavy metal pollution, and special concern must be given to tire materials for the purpose of improving the environmental conditions of road areas. The use of polyurethane as a binder material in the production of pavement mixtures has an environmental benefit in terms of pollution from both organic contaminants and heavy metals.

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Interactions of Cd2+, Co2+ and MoO42− Ions with Crushed Concrete Fines

Journal of Composites Science ◽

10.3390/jcs5020042 ◽

2021 ◽

Vol 5 (2) ◽

pp. 42

Author(s):

Victoria K. Elmes ◽

Nichola J. Coleman

Keyword(s):

Contaminated Soils ◽

Aqueous Media ◽

Fine Fraction ◽

Freundlich Isotherm ◽

Crushed Concrete ◽

Pseudo Second Order ◽

Zero Order Reaction ◽

Co Precipitation ◽

Material Accounting ◽

Effective Sorbent

Construction and demolition activities generate approximately two thirds of the world’s waste, with concrete-based demolition material accounting for the largest proportion. Primary aggregates are recovered and reused, although the cement-rich fine fraction is underutilised. In this study, single metal batch sorption experiments confirmed that crushed concrete fines (CCF) are an effective sorbent for the maximum exclusion of 45.2 mg g−1 Cd2+, 38.4 mg g−1 Co2+ and 56.0 mg g−1 MoO42− ions from aqueous media. The principal mechanisms of sorption were determined, by scanning electron microscopy of the metal-laden CCF, to be co-precipitation with Ca2+ ions released from the cement to form solubility limiting phases. The removal of Co2+ and MoO42− ions followed a zero-order reaction and that of Cd2+ was best described by a pseudo-second-order model. The Langmuir model provided the most appropriate description of the steady state immobilisation of Cd2+ and Co2+, whereas the removal of MoO42− conformed to the Freundlich isotherm. Long equilibration times (>120 h), loose floc formation and high pH are likely to limit the use of CCF in many conventional wastewater treatment applications; although, these properties could be usefully exploited in reactive barriers for the management of contaminated soils, sediments and groundwater.

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Recovery of Cenospheres and Fine Fraction from Coal Fly Ash by a Novel Dry Separation Method

Energies ◽

10.3390/en13143576 ◽

2020 ◽

Vol 13 (14) ◽

pp. 3576

Author(s):

Jan Wrona ◽

Witold Żukowski ◽

Dariusz Bradło ◽

Piotr Czupryński

Keyword(s):

Fly Ash ◽

Coal Fly Ash ◽

Fine Fraction ◽

Free Fall ◽

Raw Material ◽

Fluidised Bed ◽

Air Chamber ◽

Pneumatic Separation ◽

Bed Separation ◽

Separation Product

Aluminosilicate microspheres are a valuable fraction of coal fly ash with diverse applications due to their low density. Currently, there is no efficient and ecologically rational method of cenosphere recovery from fly ash. A combination of dry methods for the recovery of both fine ash particles and aluminosilicate microspheres from coal fly ash is presented. It is comprised of fluidised bed separation followed by screening and pneumatic separation in a free-fall air chamber. Fluidised bed separation was assisted by a mechanical activator to prevent agglomeration. This step reduced the portion of material that required further treatment by 52–55 wt.%, with the recovery of microspheres exceeding 97%. Then, the concentrates were individually subjected to pneumatic separation. The final separation product for the fly ash containing 0.64 wt.% cenospheres was a cenosphere concentrate that constituted about 17 wt.% of the initial fly ash. The recovery of cenospheres was around 81%. Usage of a combination of dry methods allowed for maintaining almost 83 wt.% of the raw material in its dry form. Furthermore, the produced fly ash grain fractions could be used for different industrial purposes.

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Microbial Community Analysis inside a Biooxidation Heap for Gold Recovery in Equador

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.262.135 ◽

2017 ◽

Vol 262 ◽

pp. 135-138 ◽

Cited By ~ 3

Author(s):

Carlos L. Aspiazu ◽

Paulina Aguirre ◽

Sabrina Hedrich ◽

Axel Schippers

Keyword(s):

Microbial Community ◽

Fine Fraction ◽

Community Analysis ◽

Gold Recovery ◽

Microbial Community Analysis ◽

Most Probable Number ◽

Rrna Gene ◽

Probable Number ◽

Cell Numbers ◽

Cell Counts

In a mine owned by the company Orenas S.A. (Equador), a biooxidation process for gold recovery has been developed. Refractory gold ore was crushed, milled and 500 ton of flotation concentrate was agglomerated by coating a support rock. This was piled up on a liner and the biooxidation process in the heap of 35x25x6 m3 was run for approximately 150 days. The oxidized material was subsequently removed for further processing. An outcrop allowed for depth dependent sampling of altogether 36 samples at three sites over the complete depth of 6 m. The fine fraction was removed from the host rock and sent to the laboratory for analysis of the microbial community. The pH ranged between 2.2 and 2.9. Total cell counts determined via counting under a fluorescence microscope after SYBR Green staining indicated a high microbial colonialization of the heap in all depths between 106 to 109 cells per g concentrate, however the highest cell numbers were mainly found in the upper 50 cm. Most-probable-number determination of living, acidophilic iron (II)-oxidizers for one site also revealed a decrease of cell numbers with depth (between 104 to 108 cells per g concentrate). Further molecular analyses of the community composition based on extracted DNA and 16S rRNA gene analyses by TRFLP and qPCR revealed a complex archaeal and bacterial community within the heap. It can be stated that an active community of acidophiles runs the biooxidation process in all sampled parts of the heap.

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Variations in mixed-layer illite/smectite diagenesis in the rift and post-rift sediments of the Jeanne d'Arc Basin, Grand Banks offshore Newfoundland, Canada

Canadian Journal of Earth Sciences ◽

10.1139/e04-004 ◽

2004 ◽

Vol 41 (4) ◽

pp. 401-429 ◽

Cited By ~ 12

Author(s):

Iftikhar A Abid ◽

Reinhard Hesse ◽

John D Harper

Keyword(s):

Mixed Layer ◽

Fine Fraction ◽

Upper Jurassic ◽

Grand Banks ◽

Depth Profiles ◽

Jeanne D'arc Basin ◽

Central Ridge ◽

Jeanne D'arc ◽

Layer I ◽

Mixed Layers

Mixed-layer illite/smectite (I/S) clays were analyzed from 22 deep exploration wells from the Jeanne d'Arc Basin on the Grand Banks offshore Newfoundland, the host of large commercial hydrocarbon accumulations discovered in the last two and a half decades. The fine fraction of the clays (<0.1 µm) consists mainly of mixed-layer I/S with minor amounts of kaolinite, illite, and chlorite. Smectite and (or) smectite-rich I/S clays were supplied to the Jeanne d'Arc Basin from Upper Jurassic to Tertiary times. Smectite-rich I/S clays occur only in shallow samples irrespective of geologic age. The proportion of illite in I/S mixed-layers, as well as the degree of ordering, increase with depth and temperature indicating that smectite-rich I/S clays have been progressively illitized in both rift and post-rift sediments of the Jeanne d'Arc Basin during burial. The transition from random to R1-ordered I/S occurs between subsurface depths of 1940 and 3720 m and crosses major stratigraphic boundaries. The transition from R1- to R3-ordered I/S generally occurs below 4000 m depth. Variable shapes of I/S depth profiles reflect the influence of temperature, fluid migration, subsidence history, basin structure, lithology, and salt diapirism on I/S diagenesis. Based on these variations, the basin can be subdivided into 4 regions with different illitization gradients. In the Southern Jeanne d'Ac Basin, advanced I/S diagenesis probably reflects uplift and denudation and (or) higher paleogeothermal gradients. Rapid increase of percent illite in I/S with depth in the Trans-Basinal Fault area is most likely controlled by upward flow of hot, K+-bearing fluids along faults. The migration of hydrocarbons probably followed the same pathways as the illitizing fluids. Delayed illitization in the Northern Jeanne d'Arc Basin and Central Ridge area reflects insufficient K+ supply because of a lack of detrital K-feldspar in the host sediment, the absence of faulting, and the presence of thick shale intervals. These findings show that I/S depth profiles may vary within the same sedimentary basin due to a variety of geological factors. Single wells generally cannot be considered representative for the basin as a whole.

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