Liquid Crystal Display Glass Research Articles

Sustainable use of organic light-emitting diode (OLED) and liquid crystal display (LCD) glass wastes as cement replacement in concrete

With the persistently increasing use of electronic and display devices, there has been a significant surge in OLED and LCD glass wastes. One way to efficiently utilize such wastes is incorporating them in mortars or concrete as supplementary cementing material (SCM) by replacing a part of cement. The use of SCMs is customary in contemporary concretes. Different industrial by-products and waste materials have been investigated earlier for such applications. In this paper, the use of OLED and LCD glass wastes as a partial replacement for cement binders has been reviewed. Mechanical properties, durability attributes, microstructural characteristics, and structural performance of the cementitious composites incorporating LCD and OLED powders have been assessed. It has been concluded that adding LCD and OLED leads to improved mechanical strength after 28-day age. The modified composites have better durability, enhanced microstructure, lower porosity, and superior overall performance. The enhanced mechanical and durability properties with LCD and OLED addition is attributed to the pozzolanic activity due to high amounts of alumina and amorphous silica. Incorporating LCD and OLED wastes in concrete as a partial cement replacement can also reduce environmental burden and concrete cost, thus promoting sustainable development.

Modification of UHPC Matrix and Fiber Surface for Improving the Mechanical Performance of Ultra-High-Performance Fiber-Reinforced Concrete

In this study, filler and silica fume were substituted by Liquid crystal display glass powder (LCDGP) and nanosilica, respectively, to improve the performance of ultra-high- performance fiber-reinforced concrete. In addition, the surface of steel fiber was modified with ethylenediaminetetraacetic acid (EDTA) solution to improve the interfacial friction between the fiber and Ultra-high-performanceconcrete (UHPC) matrix. Both LCDGP and nanosilica reacted with calcium hydroxide to form hydrates, and the fiber surface roughness increased owing to the EDTA treatment. When LCDGP was used, the compressive strength decreased owing to a decrease in packing density; however, the compressive and tensile strengths of Ultra-high-performance fiber-reinforced-concrete (UHPFRC) were improved on using nanosilica. It was observed that the surface modification of the fiber increased the friction force between the UHPC and fiber interface; therefore, it was more effective in improving the tensile strength than the compressive strength.

A combination of liquid–crystal display glass powder and slag in alkali-activated material

This study presents the feasibility of a combination of liquid–crystal display glass powder (LCDGP) and slag in alkali-activated materials using several techniques including nuclear magnetic resonance and thermodynamic modeling. Slag was replaced with LCDGP at a weight ratio of 25%, 50%, 75%, and 100%. Replacing slag with LCDGP up to 50% resulted in no strength loss and no significant changes in phase assemblages compared to alkali-activated slag. The incorporation of 25% LCDGP improved the pore structure and the reactivity of both precursors which result in increased compressive strength. This was because aluminum of LCDGP incorporated into the silicate which polymerized more C-(N)-A-S-H gel. However, the excessive use of LCDGP (more than 50%) caused a significant strength loss. Since LCDGP was responsible for lowering the pore solution’s pH, its excessive use reduced the reactivity of precursors and caused a significant strength loss. This study suggests a guideline for using LCDGP to improve the mechanical property of alkali-activated slag.

Correlation study of physical and mechanical properties of concretes with crushed LCD glass

The need to increase the sustainability of the construction industry is leading to the search for alternative sources of raw materials. Liquid crystal display (LCD) screens have been used for many years and are also rapidly ageing as a result of fast development. Therefore, the use of waste from LCD screens is an interesting avenue for the construction industry. This paper presents a very practical study of the use of old LCD screen of ground material to replace various fine aggregates. Fifteen concrete mixes of different strength levels and with different amounts of LCD powder were prepared. These are C20, C25, and C35 grade concretes, all of which contain LCD powder in quantities ranging from 15% to 60%. Results of density, compressive strength, and tensile strength at 7 and 28 days after concreting. The results are correlated with the number of replacement components and are also correlated with each other. The data presented to improve our understanding of the practical application of LCD waste aggregate in concrete. The results show that the amount of LCD powder has a direct linear effect on the compressive strength and also a direct lognormal effect on the tensile strength of concrete.

Utilization of liquid crystal display (LCD) glass waste in concrete: A review

As the demand for display devices increases, the disposal of liquid crystal display (LCD) glass waste becomes an emerging issue. It is thus necessary to make efforts to recycle bulk LCD glass waste. The construction industry can propose a solution to this by using LCD glass waste as an alternative resource for construction materials. This paper presents a state-of-the-art review on the utilization ofLCDglass waste as replacements for cement and fine aggregate. Its applications in special types of concrete, e.g., ultra-high-performance concrete (UHPC), self-compacting concrete, and geopolymers, are also investigated. Thanks to the high pozzolanicity with abundant alumina, the LCD glass powder can partially replace the cement in a classical concrete and filler of UHPC. The matrix modified with the LCD glass powder is effective in improving the medium- to long-term mechanical strength (generally at a replacement level of up to 10% or 20%) and the overall durability, with respect to alkali-silica reaction expansions, sulfate attacks, and chloride ion penetration, and freeze–thaw, as well as the pull-out resistance. However, the alternative use of LCD glass powder in metakaolin negatively affects the mechanical strength of the geopolymer, owing to the increased heterogeneity, pore size, and volume. The use of LCD glass waste as sand decreases the mechanical strength in general but leads to better workability, durability, and volume stability. Thus, LCD glass waste can be used as a new alternative ingredient for concrete, as a replacement for cementitious materials or sand.

Hydration characteristics and microstructure evolution of concrete with blended binders from LCD and OLED wastes

The use of pozzolanic waste materials as partial cement replacement is customary in contemporary concretes from the sustainability perspective. In this study, glass wastes from organic light-emitting diode (OLED) and liquid crystal display (LCD) were used waste as supplementary cementing material (SCM) in concrete. For the first time, detailed microstructural and hydration attributes have been studied for such blended concretes. Concretes with 10%, 20%, and 30% substitution of ordinary Portland cement (OPC) by OLED and LCD glass powders were developed. The resulting mechanical properties, hydration attributes, and microstructural features were studied at various ages, up to one year. Superior mechanical properties were shown after 28-day age for blended concretes; however, much profound improvement in compressive and flexural strength was observed at 1-year age. The enhanced mechanical properties of modified concretes are attributed to greater pozzolanic activity and secondary hydrates formation of OLED and LCD glass powders in alkaline cementitious matrix. Greater C-S-H gel formation, lower permeability, and more refined microstructure of the blended concrete were corroborated by thermogravimetric analysis (TGA), Rietveld quantitative phase analysis (RQPA), backscattered electron image analysis (BSE), and mercury intrusion porosimetry (MIP). 20 wt% has been found as the optimal value of cement replacement by either LCD or OLED powder. The results clearly indicate LCD and OLED can be successfully used as SCM for developing concrete with improved properties.

Up-Cycling of LCD Glass by Additive Manufacturing of Porous Translucent Glass Scaffolds

Additive manufacturing technologies, compared to conventional shaping methods, offer great opportunities in design versatility, for the manufacturing of highly porous ceramic components. However, the application to glass powders, later subjected to viscous flow sintering, involves significant challenges, especially in shape retention and in the achievement of a substantial degree of translucency in the final products. The present paper disclosed the potential of glass recovered from liquid crystal displays (LCD) for the manufacturing of highly porous scaffolds by direct ink writing and masked stereolithography of fine powders mixed with suitable organic additives, and sintered at 950 °C, for 1–1.5 h, in air. The specific glass, featuring a relatively high transition temperature (Tg~700 °C), allowed for the complete burn-out of organics before viscous flow sintering could take place; in addition, translucency was favored by the successful removal of porosity in the struts and by the resistance of the used glass to crystallization.

Suitability of liquid crystal display (LCD) glass waste as supplementary cementing material (SCM): Assessment based on strength, porosity, and durability

The use of pozzolanic waste materials as partial cement replacement is customary in contemporary concretes from a sustainability perspective. In this experimental study, the liquid crystal display (LCD) glass waste was finely ground to be used as SCM, and the potential beneficial effects in terms of strength, hydration, and durability of resulting concretes were evaluated. Concretes with 10% and 20% cement replacement by LCD glass waste powder (LCDGP) were developed and subsequently tested at various ages. It is shown that LCDGP can be successfully used as supplementary cementing material (SCM) in developing sustainable and low embodied energy concrete. The pozzolanic reactivity of LCDGP is corroborated, which has been found limited for coarser particles. Although the modified concretes exhibited lower early-age strength than the normal concrete, the mechanical properties at later ages indicated at least 5% better performance due to the pozzolanic reactivity, greater surface area, and finer particle size of LCDGP. LCDGP also proved to be very effective in improving the freezing-thawing resistance and sulfate attack of modified concretes by up to 30% and 5%, respectively. In conclusion, LCDGP is excellent in improving concrete durability and strength while also promoting sustainable development.

Performance of glass-blended cement produced by intergrinding and separate grinding methods

This study aims to investigate the grindability and performance of glass-blended cements depending on the grinding method and glass type. Two grinding methods, intergrinding and separate grinding, and two types of waste glass, liquid crystal display glass (LCDG) and soda-lime glass (SLG), were considered. To study grindability, the milling characteristics of the coarse waste glass and fine glass-blended mixtures were investigated. The four types of glass-blended cements produced by the two grinding methods and the two types of waste glass were evaluated on particle size distribution, chemical composition, heat flow of hydration, hydration behavior, strength development and mitigation in alkali–silica reaction (ASR) expansion. It was found that the intergrinding method was more cost-efficient in producing glass-blended cements than the separate grinding method. Intergrinding of the glass-blended mixtures resulted in finer cement and coarser glass fractions. The interground glass-blended cements showed faster hydration reactivity but slightly lower strength and mitigation in ASR expansion than did separately ground glass-blended cements.

Effects of waste liquid–crystal display glass powder and fiber geometry on the mechanical properties of ultra-high-performance concrete

Mechanically more performant ultra-high-performance concrete (UHPC) was developed by incorporating waste liquid–crystal display (LCD) glass powder and modifying steel fiber geometry. For this purpose, 50% of inert silica flour was replaced by LCD glass powder, and five steel fiber types with various cross-sectional shapes (circular or triangular) and twisting rates were considered. Results suggest that the glass powder was effective in enhancing the tensile and flexural performance of UHPC with straight steel fibers due to the increased frictional shear resistance at the fiber/matrix interface. However, its effectiveness was diminished when the fibers were twisted. Better tensile and flexural performances were reported for the circular fibers than that reported for triangular fibers due to the minor matrix damage and higher pullout energy. Such performance and cracking behavior of the latter could also be improved by twisting the fibers through the torsional action. The single twisting of triangular fiber improved the performance of UHPC, and no further improvement was observed by increasing the number of twisting. Synthetically, the circular fiber or singly twisted triangular fiber was considered as the most appropriate reinforcing type of UHPC.

Liquid crystal display glass powder as a filler for enhancing steel fiber pullout resistance in ultra-high-performance concrete

This study investigated the feasibility of using waste liquid crystal display (LCD) glass powder as a partial replacement for the silica flour that is typically used as a filler in ultra-high-performance concrete (UHPC). In this study, 50% of the silica flour was replaced with LCD glass powder, and its effects on the interfacial bond properties of two steel fiber shapes—circular and triangular—were evaluated. The test results indicated that the LCD glass powder effectively enhanced the bond between the steel fibers and the UHPC, which created a denser interfacial zone; this could be attributed to the filling effects of the LCD glass powder and secondary hydrates. The use of the LCD glass powder increased the pullout energy by 15–40% and the average bond strength by 16%, along with formation of additional scratches on the fiber surfaces. For the same matrix, as compared to the circular steel fibers, the triangular steel fibers yielded superior pullout resistance owing to their higher intrinsic fiber efficiency ratio. Thus, the highest average bond strength and pullout energy of 11.2 MPa and 744 mJ could be obtained from the UHPC mixture containing the LCD glass powder and triangular steel fibers.

Study on preparation and performance of biocarriers using waste liquid crystal display glass after extracting indium

A large amount of waste liquid crystal display (LCD) glass becomes a secondary waste after extracting the scarce metal indium from waste LCD by acid leaching. The feasibility of preparing biocarriers from waste LCD glass as raw materials was studied. The effects of different types and contents of foaming agents, foaming temperature and time on the biocarriers were studied. Under the condition of foaming temperature of 1050 ℃ and foaming time of 20 min, a suitable biocarrier was prepared by adding 5 % CaCO3 as a foaming agent into the waste LCD glass (denoted as Biocarrier-CaCO3). The technical indicators, which including void fraction, specific surface area, compressive strength and others of the Biocarrier-CaCO3, met the standard of CJ/T 299-2008 for water treatment. When Biocarrier-CaCO3 was applied for Shewanella cultivating, the biomass of the biofilm reached as high as 38 mg/g. In contrast, Na2CO3 was not suitable for the preparation of biocarriers for its porcelainization; SiC also failed as a foaming agent because the strength of the biocarrier could not reach the technical requirements of the product. In all, this study provided a novel strategy to recycle waste LCD glass as biocarrier to support the development of microbes and biofilm.

Synthesis of Zeolite Using Aluminum Dross and Waste LCD Glass Powder: A Waste to Waste Integration Valorization Process

In the current investigation, we synthesize zeolite using two different waste streams, such as aluminum dross and waste glass powder, for its potential application in indium and tin recovery from the leach liquor of waste liquid crystal display (LCD) glass. The aluminum dross (Al resource) and waste glass powder (Si resource) were used as raw materials for the synthesis of zeolite. Zeolite was synthesized using different weight ratios of Al dross and waste LCD glass by hydrothermal synthesis route using NaOH. The weight ratio variations of Al dross and waste LCD glass in this study are 0.3:1, 0.5:1, 1:1, 2:1, 3:1, and 4:1 using 2 M NaOH hydroxide by the hydrothermal technique. The synthesized zeolite was analyzed by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) followed by the possible application for recovery/extraction of indium and tin from leach liquor of waste LCD glasses. The indium extraction of average 93.66%, and tin extraction of 93.10% could be achieved from mixed solution indium and tin chloride. The significant achievement of the current investigation is that it can address two environment problems simultaneously, i.e., waste LCD glass and Al dross, and can be used for value recovery from waste LCD, LCD etching waste like secondary resources.

Analysis of Indium and Tin in Different Scrap Liquid Crystal Display Glass by Heavy Metal Digestion Method

Disposing of liquid crystal display (LCD) waste has significant effects on the environment, human and animal health, and metal resources by extension if inappropriately treated. In this study, we have developed a process for the separation of indium–tin oxide (ITO) glass from the LCD panel and evaluated the best digestion process for the analysis of In and Sn from ITO glass. The digestion process of scrap LCD in this work involves the separation of the polarizing film from ITO glass by environmentally friendly cold thermal shock method with liquid nitrogen, the removal of liquid crystals between the ITO glass substrates by ultrasonic cleaning, and the analysis of In and Sn from ITO glass by acid digestion method with a suitable reagent. Various brands of scrap LCDs were treated with six different digestion methods to determine In and Sn concentrations. The result of this study indicates that aqua-regia digestion procedure was the best method for the analysis of In and Sn. The concentrations of In and Sn in various brands of LCDs were in the range of 233–332 mg/kg and 43–421.5 mg/kg, respectively. Further, the analysis of In and Sn metals at different locations of the same scrap LCD was also carried out and it was observed that the concentrations of these metals (In—0.0278–0.0369% and Sn—0.0033–0.0078%) were significantly similar, with slight variations in their percentages.

Durability of Concrete Containing Liquid Crystal Display Glass Powder for Pavement

Durability of Concrete Containing Liquid Crystal Display Glass Powder for Pavement

How much material can a recycling facility source? A business-incentive based model for secondary material sourcing applied to waste LCD screen material

For low value waste materials, the ability to economically recycle scrap can be inhibited by the transportation costs associated with collecting sufficient material at a central location to reach a threshold economy of scale. Waste liquid crystal display (LCD) screen, once removed from their host devices, are an example of such a material. An economic model has been developed for estimating the amount of material that could be consolidated at a central recycling facility for processing by optimizing for the internal rate of return (IRR) for constructing and operating such a facility. The results show that the population density and high landfill tipping fees of the northeastern United States make New York and New Jersey the states associated with the highest IRR. Process sensitivity analyses reveal that for standard grade commodities produced from LCD glass, only nine states – all in the northeastern US – exhibit an IRR greater than 10% and only process about one third of the US and Canada’s LCD screen waste. For a recycler producing a high value liquid crystal product and a value-added glass product from the same waste, the impact of transportation costs becomes negligible and a facility could be operated in a state of one’s choosing to process all of the US and Canada’s waste with little impact on IRR. For the principal processing flow sheet investigated, the optimal plant capacity is estimated to be about 11,000 tonnes per year.

Waste Liquid-Crystal Display Glass-Directed Fabrication of Silicon Particles for Lithium-Ion Battery Anodes

The rapid increase of waste liquid-crystal display (LCD) is becoming a serious problem. Among the constituents of waste LCD panels, glass substrates are not completely recycled and buried in landfills because of the lack of recycling technologies. In order to establish a recycling strategy with sustainable process and application, we fabricated silicon (Si) materials into lithium-ion battery (LIB) anodes through the magnesiothermic reduction of waste LCD glasses. To synthesize high-quality Si materials, an optimized pretreatment process is proposed to remove undesirable contents from waste LCD glasses. In order to achieve high areal capacity for practical applications, we conducted facile and cost-effective electrode maturation, which improves the cohesion and adhesion of the Si anodes. The electrochemical measurement results showed that the waste LCD glass-derived Si electrodes exhibited high areal and gravimetric capacities of 6.3 mA h cm–2 and 3438 mA h g–1, respectively, in the initial cycle. The elec...

Assessment of compressive strength of cement mortar with glass powder from the early strength

The sustainable development principle of replacing natural resources with renewable material is an important research topic. In this study, waste LCD (liquid crystal display) glass powder was used to replace cement (0%, 10%, 20% and 30%) through a volumetric method using three water-binder ratios (0.47, 0.59, and 0.71) to make cement mortar. The compressive strength was tested at the ages of 7, 28, 56 and 91 days. The test results show that the compressive strength increases with age but decreases as the water-binder ratio increases. The compressive strength slightly decreases with an increase in the replacement of LCD glass powder at a curing age of 7 days. However, at a curing age of 91 days, the compressive strength is slightly greater than that for the control group (glass powder is 0%). When the water-binder ratios are 0.47, 0.59 and 0.71, the compressive strength of the various replacements increases by 1.38-1.61 times, 1.56-1.80 times and 1.45-2.20 times, respectively, during the aging process from day 7 to day 91. Furthermore, a prediction model of the compressive strength of a cement mortar with waste LCD glass powder was deduced in this study. According to the comparison between the prediction analysis values and test results, the MAPE (mean absolute percentage error) values of the compressive strength are between 2.79% and 5.29%, and less than 10%. Thus, the analytical model established in this study has a good forecasting accuracy. Therefore, the proposed model can be used as a reliable tool for assessing the design strength of cement mortar from early age test results.

Recycling of waste glass generated from end-of-life LCD devices: A feasibility study using simulated waste glass

The liquid crystal display (LCD) industry has undergone drastic growth over the past decade. Considering that the lifetime of an LCD device is approximately ten years, a huge end LCD waste glass (ELWG) is being produced from end-of-life LCD devices. The recycling of ELWG derived from LCD device produced before 2011 is limited by the presence of toxic components such as As, Sb and Ba. In this work, the potential of recycling ELWG was examined to be used in the glass wool industry. 17 glass batches using four different simulated ELWGs (mixtures corresponding to LCD glasses produced in 2006, 2008, 2009, and 2010) were prepared and melted. ELWG was introduced up to 20% of the total glass. Two fixed viscosity points (Tm, Tw) corresponding to 102 and 103 dPas, and the liquidus temperature (TL) were determined in the melt state, and leaching tests of the glass powder in an acidic solution based on the toxicity characteristic leaching procedure (TCLP) were also carried out. As the ELWG content was increased, the Tm, Tw, and TL values did not show a linear relationship with the ELWG content, but some fluctuation in the values was observed. The Tm value showed a larger deviation of 28–36 °C from that of the original glass than the Tw (6–14 °C) and TL (2–16 °C) values. As and Sb were not detected in the leaching tests, and the Ba concentration (1.232–2.279 mg/L) was much lower than the TCLP regulatory level (100 mg/L). The observed TW-TL values suggested that the replacement of 20% or more of the total glass by ELWG is possible. Additionally, the economic and environmental effects of the recycling process were discussed.

Value Recovery from Waste Liquid Crystal Display Glass Cullet through Leaching: Understanding the Correlation between Indium Leaching Behavior and Cullet Piece Size

For hydrometallurgical recovery of indium from glass cullet after dismantling a waste liquid crystal display (LCD), leaching is the rudimentary stage. Though size reduction of the cullet pieces adds convenience for recycling, from an efficiency and cost-effectiveness perspective regarding leaching process development, determining the proper cullet piece size is essential. Hence, in this study, leaching efficiency of indium as a function of cullet piece size was investigated, wherein the proper mechanical classification of crushed glass cullet could be addressed. The optimum conditions of 5 M mineral acid as the lixiviant, pulp density of 500 g/L, temperature of 75 °C, agitation speed of 500 rpm, 2 h process time were kept constant for the leaching studies. It was concluded that the size of the waste LCD cullet inversely affected the leaching efficiency of indium. For efficient leaching, a smaller cullet size is recommended; hence, waste LCD should be crushed to pieces 1 mm or smaller. Indium leaching behavior comparison using HCl, HNO3, H2SO4 revealed that all three mineral acids had similar leaching efficiencies. The reported process provides the missing link between physical dismantling and chemical processing for indium recovery via techno-economical-sustainable process development.