Triboelektrische Trennung - Eine neue Methode zur Trennung feiner organischer Pulver?

Triboelectric separation is a technique to separate dry powders according to their ability to generate charge. Charge generation occurs due to the contact of and subsequent separation of two surfaces. A physical description of the triboelectric effect is still unknown. For particles flowing through a tube, particle-particle and particle-wall interaction occur. To enhance separation properties of binary powder mixtures charge generation are enlarged by increasing particle-particle interactions, whereas materials of the tube wall do not influence the separation properties.Die triboelektrische Trennung ist eine Methode, um trockene Pulver durch ihre Ladungserzeugung zu trennen. Die Ladungserzeugung erfolgt durch Kontakt und anschließende Trennung zweier Oberflächen. Eine physikalische Beschreibung des triboelektrischen Effekts ist noch nicht bekannt. Bei Partikeln, die durch ein Rohr strömen, treten Partikel-Partikel und Partikel-Wand Kontakte auf. Ein Erhöhen der Partikel-Partikel Kontakte führt zu erhöten Trenneigenschaften, wohingegen die Materien der Rohrwand diese nicht beeinflussen

Postupci razvrstavanja otpada kod postupka recikliranja proizvoda

In the process of waste management, there is the need to separate and sort waste products, which consist of different materials that have different properties, so that the recycling process could be carried out successfully. Here are described manual sorting procedures and mechanical classification of waste products, which are based on the various properties of materials, such as sorting by shape, magnetic separation procedures, classification based on electrical conductivity and classification based on density. As much as the mechanical procedures contributed to the sophistication of waste classification, in special cases, such as in the presence of dirt, oil and other contaminants that cannot be completely removed by mechanical methods, manual sorting remains the main option.Kod prerade otpada potrebno je otpadne proizvode, koji se sastoje od raznih vrsta materijala raznih svojstava, razdvojiti te nakon toga razvrstati kako bi se što uspješnije proveo postupak recikliranja. Opisano je ručno razvrstavanje te postupci mehaničkog razvrstavanja otpada koja se temelje na različitim svojstvima materijala kao što su razvrstavanje oblikom, magnetni postupci razvrstavanja, razvrstavanje na osnovi električne vodljivosti te razvrstavanje na osnovi gustoće. Mehanički postupci doprinose sofisticiranju razvrstavanja otpada, ali u posebnim slučajevima kod prisutnosti nečistoća, ulja i drugih zagađenja koja se ne mogu potpuno ukloniti mehaničkim postupcima, ručno razvrstavanje ima velik značaj i često ostaje glavna opcija

State of the art of plastic sorting and recycling : Feedback to vehicle design

Today car manufacturers are beginning to integrate recycling constraints in the first stages of the design of a new car due to their concern regarding the effects of car design on the recovery of material after End-of-Life Vehicle treatment. Improved understanding of the recycling process can help designers to avoid contaminants in the recycled product and improve the efficiency of current and new sorting methods. The main goal of this paper is to describe the state of the art of the technical efficiency of recovery channels for plastics in Europe in order to define requirements for automotive plastic part design. This paper will first present the results of a survey on industrial and innovative recycling technologies mainly originating from the mining sector, and secondly a simplified methodology for car design integrating plastic recycling constraints. This methodology concerns material association and compatibility, the type of assemblies favourable to better recycling, and better reuse of recycled products in cars.Renault Research Direction FR TCR LAB 1 13, Service 641000-Recycling Engineering, 1 avenue du Golf, 78288 Guyancourt Cedex, Franc

Triboelectrostatic Separation of Mineral Matter from Slovakian Coals

V èlánku sú diskutované niektoré technické aspekty triboelektrostatickej separácie a výs-ledky aplikácie tohto postupu pri úprave troch typov uhlia, konkrétne energetického uhlia z Cíg¾a, Handlovej a Novák. Bolo zistené, e úèinnos separácie ve¾mi úzko závisí na druhu separovan uhlia. Prvé výsledky preukázali súvislos medzi úèinnosou separácie obsahom popola v uhlí

High Ash Non Coking Coal preparation by Tribo-Electrostatic Technique

Tribo-electrostatic method is applied to beneficiate non-coking Indian thermal coal from Ramagundam coal mines containing nearly 45% ash content. The microscopic studies revealed that quartz and kaolinite are the dominant mine-rals whereas illite, goethite, siderite and pyrite are the minor inclusions in the coal. Contact electrification of ash forming minerals and coal matter has been carried out using different tribo-charger materials of Al, Cu, brass, perspex and teflon. The Cu tribo-charger found to be opti-mum to acquire differential charge between ash-forming inorganics and coal matter. The temperature effect on the magnitude of contact charge acquisition found to be sign-ificant. Tests on a laboratory in-house built triboelectro-static free-fall separator with minus 300 microns size fraction of coal showed that the ash content can be reduc-ed from 45% to about 18% and it is feasible to obtain a clean coal as judged by the washability studies. The results illustrate that the non-coking coals can be bene-ficiated using the scientific knowledge on the response and behaviour of coal and noncoal matters to electric charges

A Simple μ-PTV Setup to Estimate Single-Particle Charge of Triboelectrically Charged Particles

Triboelectric separation is a useful phenomenon that can be used to separate fine powders. To design technical devices or evaluate the potential of powders to be triboelectrically separated, knowledge about the charge distribution on a single-particle level has to be obtained. To estimate the single-particle charge distribution in an application-oriented way, a simple μ-PTV system was developed. The designed setup consists of a dispersing and a charging unit using a Venturi nozzle and a tube, respectively, followed by a separation chamber. In the separation chamber, a homogenous electrical field leads to a deflection of the particles according to their individual charge. The trajectories of the particles are captured on single frames using microscope optics and a high-speed camera with a defined exposure time. The particles are illuminated using a laser beam combined with a cylindrical lens. The captured images enable simultaneous measurement of positively and negatively charged particles. The charge is calculated assuming a mean particle mass derived from the mean particle size. Initial experiments were carried out using starch of different botanical origins and protein powder. Single-component experiments with starch powders show very different charge distributions for positively and negatively charged particles, whereas protein powder shows bipolar charging. Different starch-protein mixtures show similar patterns for positive and negative charge distributions

Evaluating the Use of Tribocharging in the Electrostatic Beneficiation of Lunar Simulant

Any future lunar base needs materials to provide thermal and radiation protection. Many factors point to the use of lunar materials as industrial feedstocks. Sintering of full-scale bricks using whole lunar dust has been accomplished. Refinement of soil beneficial before processing means less energy. Triboelectric separation of coal from minerals, quartz from feldspar, and phosphorous from silica and iron ore successively achieved. The Lunar environment ideal for electrostatic separation (1) lack of moisture (2) lower gravitational pull (3) higher voltages in vacuu

Control of mercury emissions using unburned carbon from combustion by-products

Mercury emission from a flue gas such as that generated by a coal fired power plant is controlled by injecting into the flue gas unburned carbon purified from ash such as fly ash or wood ash. The unburned carbon adsorbs the mercury and is later removed from the flue gas by a particle separator. The unburned carbon collected from ash is significantly lower in cost compared to activated carbon presently used in such a process. The unburned carbon is concentrated in the sorbent by one or more separation processes used to remove noncarbon particles from the fly ash. These processes include gravity separation, electrostatic separation, froth flotation, magnetic separation and size classification. Mercury adsorption is further increased by oxidation of the carbon surface.https://digitalcommons.mtu.edu/patents/1066/thumbnail.jp

Electrostatic Beneficiation of Lunar Simulant

Electrostatic beneficiation of lunar regolith is a method allowing refinement of specific minerals in the material for processing on the moon. The use of tribocharging the regolith prior to separation was investigated on the lunar simulant MLS-I by passing the dust through static mixers constructed from different materials; aluminum, copper, stainless steel, and polytetrafluoroethylene (PTFE). The amount of charge acquired by the simulant was dependent upon the difference in the work function of the dust and the charging material. XPS and SEM were used to characterize the simulant after it was sieved into five size fractions (> 100 pm, 75-100 pm, 50- 75 pm, 50-25 pm, and 100 pm) size fractions were beneficiated through a charge separator using the aluminum (charged the simulant negatively) and PTFE (charged positively) mixers. The mass fractions of the separated simulant revealed that for the larger particle size, significant unipolar charging was observed for both mixers, whereas for the smaller particle sizes, more bipolar charging was observed, probably due to the finer simulant adhering to the inside of the mixers shielding the dust from the charging material. Subsequent XPS analysis of the beneficiated fractions showed the larger particle size fraction having some species differentiation, but very little difference for the smaller.size. Although MLS-1 was made to have similar chemistry to actual lunar dust, its mineralogy is quite different. On-going experiments are using NASA JSC-1 lunar simulant. A vacuum chamber has been constructed, and future experiments are planned in a simulated lunar environment