• Resources Recycling
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• v.29 no.3
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• pp.61-74
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• 2020

This study was conducted to improve the recycling process of waste fluorescent lamp, and investigate the possibility of using the waste fluorescent lamp glass as a raw material for glass beads, the leaching method of rare earth from the waste phosphor powder, and the possibility of solvent extraction of rare earth from the rare earth leaching solution. The waste phosphor contained 28.9% yttrium oxide, 3.46% cerium oxide, 1.95% europium oxide, 1.76% terbium oxide, and 1.43% lanthanum oxide. As a result of the trial production of glass beads using waste fluorescent lamp glass, it was judged that the production yield and quality were excellent, so that waste fluorescent lamp glass could be used as a raw material for glass beads. The soda roasted waste phosphor was leached in water and thereby the aqueous solution was blown with CO₂ to drop the pH to about 7, Then, Al, Si and residual N₂CO₃ were dissolved, and NaAlCO₃(OH)₂ and SiO₂ were precipitated in the aqueous solution. In the solvent extraction of cyanex272-hydrochloric acid, cyanex272-sulfuric acid, D2EHPA-hydrochloric acid, D2EHPA-sulfuric acid, Ionquest290-hydrochloric acid, Ionquest290-sulfuric acid, p507-hydrochloric acid using xylene as a diluent, the extraction yield of Y, Eu, Ce, La, and Tb are close to 100%. However, in this conditions, the difference in extraction yield for each element, that is, selectivity is 16% or less.

• Resources Recycling
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• v.29 no.3
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• pp.51-60
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• 2020

This study was carried out to get the optimum conditions for manufacturing high refractive glass beads from waste fluorescent lamp glass. Chemical composition, X-ray diffraction pattern, particle size distribution, refractive index of glass beads, and the effect of air mixing ratio and ejection rate were investigated. The obtained results are as follows. The X-ray diffraction pattern and chemical composition of glass beads made of waste fluorescent glass are similar to common glass except ReO₂ 0.0108 wt%, BaO 0.071 wt%, NiO 0.0039 wt% and CaO 7.8 wt% but 11.7 wt% of common glass. The glass beads made of waste fluorescent lamp glass have the narrower particle size distribution of and the higher refractive index than the glass beads made of common glass. The optimal conditions of kiln operation for manufacturing glass beads from waste fluorescent lamp glass are 20 m/sec of ejection rate, 1.7 of air mixing ratio, and 940℃ of temperature.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.421-426
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• 2001

The pneumatic classification and acidic leaching behaviors of phosphor sludge have been examined to establish the recycling system of rare earth components contained in waste fluorescent lamp. At first, separation characteristic of rare earth components and calcium phosphate in phosphor sludge was investigated by pneumatic classification. After pneumatic classification of phosphor sludge, rare earth components were leached in various acidic solutions and sodium hydroxide solution. For recovery of soluble component in leaching solution, rare earth components were separated as hydroxide and oxalate precipitations. The experimental results obtained are summarized as follows: (1) In classification process, rare earth components in phosphor sludge were concentrated to 29.3% from 13.3%, and its yield was 32.9%. (2) In leaching process, sulfuric acid solution was more effective one as a leaching solvent of rare earth component than other solutions. Y and Eu components in phosphor sludge were dissolved in sulfuric acid solution of 1.5 k㏖/㎥, and other rare earth components were rarely dissolved in leaching solution. Leaching degrees of Y and Eu were respectively 92% and 98% in the following optimum leaching conditions; sulfuric acid concentration is 1.5 k㏖/㎥ , leaching temperature 343 K, leaching time 3.6 ks and pulp concentration 30 kg/㎥. (3) Y and Eu components of phosphor sludge contained in waste fluorescent lamp were, effectively recovered by three processes of pneumatic classification, sulfuric acid leaching and oxalate precipitation methods. Their recovery was finally about 65 %, and its purity was 98.2%.

• Journal of Environmental Policy
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• v.14 no.1
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• pp.135-158
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• 2015

An efficient management system of mercury-containing waste was designed by reviewing the management and treatment of spent fluorescent lamp in Korea and foreign countries. According to Waste Management Act in Korea, mercury-containing wastes from households are classified as municipal solid wastes even though mercury-containing wastes pose hazardous risks. In general, hence, mercury-containing wastes from households are not being managed properly because those wastes from households were not classified as specific wastes (or hazardous wastes). Some mercury-containing wastes are managed as a mandatory target item in waste charge system and Extended Producer Responsibility (EPR) system under Act on Promotion for Saving and Recycling of Resources. An efficient management plan of mercury-containing wastes can be derived with an improved collection system, designating disposal sites and advanced treatment facilities for spent fluorescent lamps. Finally, the role of each agent involved from collection to disposal of mercury-containing wastes was suggested to establish the efficient management system for mercury-containing waste.

• Journal of Powder Materials
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• v.22 no.1
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• pp.27-31
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• 2015

Flat panel display devices are mainly used as information display devices in the 21st century. The worldwide waste flat panel displays are expected at 2-3 million units but most of them are land-filled for want of a proper recycling technology More specifically, rare earth metals of La and Eu are used as fluorescent materials of Cold Cathode Flourscent Lamp(CCFL)s in the waste flat panel displays and they are critically vulnerable and irreplaceable strategic mineral resources. At present, most of the waste CCFLs are disposed of by land-filling and incineration and proper recovery of 80-plus tons per annum of the rare earth fluorescent materials will significantly contribute to steady supply of them. A dearth of Korean domestic research results on recovery and recycling of rare earth elements in the CCFLs prompts to initiate this status report on overseas research trends and noteworthy research results in related fields.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.8-15
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• 2010

Besides its basic function of illuminating a space, lighting can greatly affect the efficiency of a space when an advanced technology and planning, together with the effects of various presentations, are applied to lighting. A lighting plan suitable for maximizing the efficiency of a space will only be made feasible by considering the location of a space and the characteristics of the lamps to be used. In particular, the lighting plan for a space with a special function requires prior investigation and analysis of that space. In this study, the feasibility of a lighting environment for the tunnel of a radioactive waste disposal facility is investigated via a prior lighting design and simulation, which take into account the spatial characteristics of the tunnel. For this study, the use of fluorescent induction lamp is suggested, and the standards of lighting plan and structure are followed depending on the location of each segment of the tunnel. Then, a simulation analysis is conducted to investigate the feasibility of the plan.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.303-306
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• 2002

The EMI filter used in switching apparatus is designed on the basis of personal designer experience. A try and error approach leads to a considerables waste of time without assurance to come out to a good solution. The difficulty in the right choice of the component values resides on the dominant role played by their parasitic components at high frequencies and is aggravated by the poor knowledge of the internal impedance of the noise generators. In this paper, we proposed the design technique for the EMI filter effectively using the LISN and the EMI analyzer in the industrial field.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.509-513
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• 2010

Recently, an amount of waste electronic devices such as LED and trichromatic fluorescent lamp has increased with the development of electronic industry. Reportedly, rare earth metals such as yttrium and europium have been discovered in the waste electronic devices. In order to improve the selectivity of yttrium and europium, the effects of the following factors on recovery experiment have been considered : i) fatty acids with various alkyl chain lengths, ii) the concentration of extractant, and iii) pH. The results show that the extraction efficiencies decrease at the same pH with decreasing the concentration of extractant and so $pH_{0.5}$ (That value of pH in an aqueous phase at which the distribution ratio is unity at equilibrium: 50% of the solute is extracted (E = 0.5) only when the phase ratio is unity.) moves into higher pH. The highest selectivity of yttrium and europium was obtained with tetradecanoic acid as extractant. The extraction mechanism of yttrium and europium was varied with the change of concentration of the tetradecanoic acid. $MR_3$single-species was formed from the yttrium and europium ion in the extractant concentration less than 0.1 M. On the other hand, the yttrium or europium ion is solvated with three molecules of tetradecanoic acid monomer like $MR_3{\cdot}$ 3RH in the extractant concentration more than 0.1 M.