The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform

Tungchai Ling - One of the best experts on this subject based on the ideXlab platform.

  • recycling difficult to treat e waste cathode ray tube glass as construction and building materials a critical review
    Renewable & Sustainable Energy Reviews, 2018
    Co-Authors: Zhitong Yao, Tungchai Ling, Prabir Kuma Sarke, Jie Liu, Junhong Tang
    Abstract:

    Abstract cathode ray tubes (CRTs) waste generation has become a great environmental challenge worldwide. CRT glass possesses reasonable intrinsic strength, low water absorption and rich in silica, which makes the glass suitable for use as sand or pozzolan in construction materials. This work presents a comprehensive overview of literature reporting on the reuse of CRT glass to prepare glass-ceramics; cement mortar, paste, and concrete; and bricks. The effects of various critical factors on the resulting products’ performance, preparation mechanisms, leaching behavior, lead fate, and environmental and human safety were investigated. The comparison of these recycling methods, and directions for future research were discussed and reported as well. Preparing cement mortar, paste, and concrete from CRT glass offer added advantages in terms of quantity of recyclable cathode ray tube glass at a given time, with minimal environmental and economic implications and thus could be an a promising value-added uses for CRT glass. The geographical distance between waste CRT glass sources and processing facilities, public policies should be taken into account in its recycling.

  • utilizing recycled cathode ray tube funnel glass sand as river sand replacement in the high density concrete
    Journal of Cleaner Production, 2013
    Co-Authors: Hui Zhao, Chi Su Poo, Tungchai Ling
    Abstract:

    Abstract The rapid advance in the electronics industry has led to the disposal problem related to the cathode ray tube (CRT) glass waste. In this study, the Ordinary Portland cement (OPC) of 15% was replaced by fly ash to mitigate the potential of alkali–silica reaction (ASR) expansion, the crushed nitric acid-treated CRT funnel glass sand (TCF) was used to replace river sand fine aggregate of 0%, 25%, 50%, 75% in the high-density concrete. The fresh, mechanical properties of the high-density concrete containing TCF glass sand were studied, the alkali–silica reaction (ASR) of the mortar and drying shrinkage of the concrete were also evaluated. The test results showed that the use of TCF glass sand improved the fresh properties of the concrete, but reduced the mechanical properties of the concrete. Furthermore, at the drying period of 56 days, all concrete mixtures had an acceptable drying shrinkage value below 0.075%. ASR expansion values of the mortar with TCF glass sand were found to be below the limit of 0.1% at tested age of 14 days. Preliminary results obtained from this study had demonstrated that the CRT funnel glass (an original hazardous material) can be treated, processed and reutilized for the production of the high-density concrete.

  • properties of mortar prepared with recycled cathode ray tube funnel glass sand at different mineral admixture
    Construction and Building Materials, 2013
    Co-Authors: Zhao Hui, Chi Sun Poon, Tungchai Ling
    Abstract:

    Abstract With rapid advances in the electronic industry, the management of cathode ray tube (CRT) glass waste has become a major environmental problem. In this study, 25% Ordinary Portland cement was replaced by Fly ash (FA) or Ground granulated blast-furnace slag (GGBFS), the crushed CRT funnel glass sand untreated with nitric acid (n-TFG) was used to replace river sand fine aggregate of 0%, 25%, 50%, 75% in the mortar. The fresh, mechanical properties of the mortar were studied, the alkali–silica reaction (ASR) expansion, drying shrinkage and leaching of lead from mortar were evaluated. The test results showed, the use of n-TFG glass sand improves fresh properties of the mortar. The mortar with n-TFG glass sand has higher mechanical properties than control mortar. At the drying shrinkage period of 56 days, drying shrinkage of nearly all the mortar with n-TFG glass sand are higher than the limit of 0.075%. ASR expansion of the mortar are found to be below 0.1% at 14 days tested age, except the mortar with GGBFS and 75% n-TFG glass sand. The lead leaching from mortar with n-TFG glass sand was reduced comparing the content of the leachable lead from n-TFG glass sand. Moreover, at a given replacement level of n-TFG glass sand, FA series mortar has better fresh properties, a lower wet density, mechanical properties, drying shrinkage, ASR expansion and the leaching of lead than GGBFS series mortar.

Tieyong Zuo - One of the best experts on this subject based on the ideXlab platform.

  • reclamation and harmless treatment of waste cathode ray tube phosphors novel and sustainable design
    ACS Sustainable Chemistry & Engineering, 2018
    Co-Authors: Xiaofei Yin, Xiangmiao Tian, Wei Wang, Yinan Zhang, Tieyong Zuo
    Abstract:

    In this paper, we propose a novel and sustainable process for recycling rare earths (REs) and zinc (Zn) simultaneously from waste cathode ray tube (CRT) phosphors. First, 95% of the impurities such as glass cullets and aluminum foils are removed by simple screening. Then, a self-propagating, high-temperature synthesis reaction following a water-leaching process is performed to recycle Zn selectively. The REs are recycled by a combined process of oxidative leaching and ionic-liquid-based extraction. They are then regenerated to form a new Y2O3:Eu3+ phosphor. By following this green recycling design, the recovery efficiencies of REs and Zn reach 99.5% and 99%, respectively. The negative bivalent sulfur in ZnS and Y2O3:Eu3+ is converted completely to SO42–, which efficiently avoids the secondary pollution. It should also be pointed out that the main recovery processes are all carried out at room temperature, and the “three wastes” emissions are minimized throughout the process. This work is expected to open ...

  • Reclamation and Harmless Treatment of Waste cathode ray tube Phosphors: Novel and Sustainable Design
    2018
    Co-Authors: Xiaofei Yin, Xiangmiao Tian, Wei Wang, Yinan Zhang, Tieyong Zuo
    Abstract:

    In this paper, we propose a novel and sustainable process for recycling rare earths (REs) and zinc (Zn) simultaneously from waste cathode ray tube (CRT) phosphors. First, 95% of the impurities such as glass cullets and aluminum foils are removed by simple screening. Then, a self-propagating, high-temperature synthesis reaction following a water-leaching process is performed to recycle Zn selectively. The REs are recycled by a combined process of oxidative leaching and ionic-liquid-based extraction. They are then regenerated to form a new Y2O3:Eu3+ phosphor. By following this green recycling design, the recovery efficiencies of REs and Zn reach 99.5% and 99%, respectively. The negative bivalent sulfur in ZnS and Y2O3:Eu3+ is converted completely to SO42–, which efficiently avoids the secondary pollution. It should also be pointed out that the main recovery processes are all carried out at room temperature, and the “three wastes” emissions are minimized throughout the process. This work is expected to open new avenues for highly efficient, energy-saving, and pollution-reducing recovery processes for waste CRT phosphors

J M F Ferreira - One of the best experts on this subject based on the ideXlab platform.

  • the use of egg shells to produce cathode ray tube crt glass foams
    Ceramics International, 2013
    Co-Authors: Hugo R Fernandes, Fernanda Andreola, Luisa Barbieri, Isabella Lancellotti, M J Pascual, J M F Ferreira
    Abstract:

    Cleaned cathode ray tube (CRT) (panel and funnel) waste glasses produced from dismantling TV and PC colour kinescopes were used to prepare glass foams by a simple and economic processing route, consisting of a direct heating of glass powders at relatively low temperatures (600–800 1C). This study reports on the feasibility of producing glass foams using waste egg shells as an alternative calcium carbonate-based (95 wt%) foaming agent derived from food industry. The foaming process was found to depend on a combination of composition, processing temperature and mixture of raw materials (glass wastes). Hot stage microscopy (HSM), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize foams and evaluate the foaming ability and the sintering process. The experimental compositions allowed producing well sintered glass foams with suitable properties for some functional applications with environmental benefits such as: (1) reduced energy consumption because of the low heat treatment temperatures used; and (2) materials produced exclusively from residues. & 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Takashi Okada - One of the best experts on this subject based on the ideXlab platform.

  • removal of lead from cathode ray tube funnel glass by combined thermal treatment and leaching processes
    Waste Management, 2015
    Co-Authors: Takashi Okada, Fumihiro Nishimura, Susumu Yonezawa
    Abstract:

    Abstract The reduction melting process is useful to recover toxic lead from cathode ray tube funnel glass; however, this process generates SiO 2 -containing residues that are disposed in landfill sites. To reduce the volume of landfill waste, it is desirable to recycle the SiO 2 -containing residues. In this study, SiO 2 powder was recovered from the residue generated by reduction melting. The funnel glass was treated by a process combining reduction melting at 1000 °C and annealing at 700 °C to recover a large quantity of lead from the glass. The oxide phase generated by the thermal treatment was subjected to water leaching and acid leaching with 1 M hydrochloric acid to wash out unwanted non-SiO 2 elements for SiO 2 purification. In the water washing, the oxide phase was microparticulated, and porous structures formed on the oxide surfaces. This increased the surface area of the oxide phase, and the unwanted elements were effectively washed out during the subsequent acid leaching. By controlling the acid leaching time and the amount of added acid, porous and amorphous SiO 2 (purity >95 wt%) was recovered. In the obtained SiO 2 -concentrated product, unrecovered lead remained at concentrations of 0.25–0.79 wt%. When the Na 2 CO 3 dosage in the thermal treatment was increased, the lead removal by acid leaching was enhanced, and the lead concentration in the obtained product decreased to 0.016 wt%.

  • lead extraction from cathode ray tube funnel glass melted under different oxidizing conditions
    Journal of Hazardous Materials, 2015
    Co-Authors: Takashi Okada
    Abstract:

    Lead was extracted into hydrochloric acid from cathode ray tube funnel glass melted under reducing atmosphere, oxidizing atmosphere, or a sequential combination of both to mechanistically investigate effects of the melting atmosphere on lead extraction. Melting funnel glass in a reductive atmosphere led to the generation of metallic lead particles that were readily soluble in the acid, increasing the quantity of lead extracted into the acid. Meanwhile, the glass product obtained after melting funnel glass in an oxidative atmosphere exhibited higher corrosion resistance in the acid, and the quantity of lead extracted from the treated glass decreased. However, Na2CO3 addition to the glass during melting hindered the enhancement of corrosion resistance and the immobilization of lead in the acid. X-ray photoelectron spectroscopic analysis of the treated glass samples showed that the positions of the peak or the profiles of the spectra attributed to Pb 4f, Si 2p, and O 1s signals were modified by oxidative melting, an indication that oxidative melting results in structural changes in the SiO2 framework of the glass.

Zhao Hui - One of the best experts on this subject based on the ideXlab platform.

  • properties of mortar prepared with recycled cathode ray tube funnel glass sand at different mineral admixture
    Construction and Building Materials, 2013
    Co-Authors: Zhao Hui, Chi Sun Poon, Tungchai Ling
    Abstract:

    Abstract With rapid advances in the electronic industry, the management of cathode ray tube (CRT) glass waste has become a major environmental problem. In this study, 25% Ordinary Portland cement was replaced by Fly ash (FA) or Ground granulated blast-furnace slag (GGBFS), the crushed CRT funnel glass sand untreated with nitric acid (n-TFG) was used to replace river sand fine aggregate of 0%, 25%, 50%, 75% in the mortar. The fresh, mechanical properties of the mortar were studied, the alkali–silica reaction (ASR) expansion, drying shrinkage and leaching of lead from mortar were evaluated. The test results showed, the use of n-TFG glass sand improves fresh properties of the mortar. The mortar with n-TFG glass sand has higher mechanical properties than control mortar. At the drying shrinkage period of 56 days, drying shrinkage of nearly all the mortar with n-TFG glass sand are higher than the limit of 0.075%. ASR expansion of the mortar are found to be below 0.1% at 14 days tested age, except the mortar with GGBFS and 75% n-TFG glass sand. The lead leaching from mortar with n-TFG glass sand was reduced comparing the content of the leachable lead from n-TFG glass sand. Moreover, at a given replacement level of n-TFG glass sand, FA series mortar has better fresh properties, a lower wet density, mechanical properties, drying shrinkage, ASR expansion and the leaching of lead than GGBFS series mortar.