Cathode Ray Tube Research Articles

Effect of CRT glass particle size on the lead leachability of alkali-activated materials

Alkaline activation is an interesting manufacturing process from an environmental point of view as it allows the use of waste containing amorphous SiO2 and Al2O3 as starting material, such as glass, bottom and fly ashes. However, the presence of heavy elements in these waste materials can limit their use since they are released during the dissolution stage and not always enter totally in the new structure formed. In this work, the feasibility of using glass from Cathode Ray Tubes (CRT) with a high particle size to reduce lead leaching has been studied.

The life-cycle assessment of greenhouse gas emissions and life-cycle costs of e-waste management in Thailand

There is no clear direction in the management of electrical and electronic waste products (e-waste), as there are no regulations on ways to do so. This research attempts to understand the trade-off between the economic value and the environmental effects of the current disposal of e-waste to find ways to optimize waste management, focusing on cellphones, television cathode ray tubes, desktop computers, and air conditioners. A life cycle greenhouse gas and life cycle costs were conducted. Under the e-waste management status quo, most household e-waste is kept in houses because owners do not know where to discard it. In addition, informal sectors, such as domestic farmers or workers, have been actively involved in collecting and dismantling e-waste for more than a decade, leading to poor management standards for both health and the environment. Without e-waste management regulations, informal dismantlers of products gain slight profits by collecting and selling parts and discarding all non-recyclable waste in municipal garbage dumps. The current practice actually adds greenhouse gas to the atmosphere mainly due to improper logistics management and discarding of refrigerants. The logistics are inefficient because the dismantling communities and recycling locations are far apart. Most e-waste is generated, and most recycling industries are located in the central region (the richest areas), while the dismantling communities are located in the northeastern region (the poorest areas). Furthermore, the life cycle of greenhouse gas and the life cycle costs of e-waste are affected by transportation, and not all e-waste parts can be recycled within the country. High-tech mineral extraction cannot be practiced in the country, and thus, circuit boards and batteries are exported for recycling. To promote a circular economy, e-waste management regulations should be implemented, the costs of proper e-waste management should be internalized, and a full recycling industry should be established in the country.

OLED: New Generation Display Technology

As time gets advanced multiple progressions have happened in the field of display devices. In this field first came a small LED then after CRT (Cathode Ray Tube) which is used in present days but due to its heaviness, we do not carry it from one place to another. Then after came LCD (Liquid Crystal Display), the problem of bulkiness and required large area overcome by LCD, the only problem with LCD is that it cannot see a clear picture from different angles. LCD is a lightweight and flexible plastic substrate. After all these innovations OLED came and OLED beat all issues of LCD and CRT. OLED is light and slim in design, it does not require any kind of backlight, OLEDs are self-luminous. Polymers are using to fabricate OLEDs or unlike LCDs small molecules in the flat panel zone. It has low power consumption (only 2-10 volts) also OLEDs has a wide viewing angle (up to 160 degrees). The applications of OLEDs in electronics are on the increase on daily basis from camera to cell phones to OLED televisions.

The 60th Anniversary of TFTs and the Evolution of High‐Resolution Displays

The 60th Anniversary of TFTs and the Evolution of High‐Resolution Displays

Potential for Use of Recycled Cathode Ray Tube Glass in Making Concrete Blocks and Paving Flags.

The potential to use waste glass, including cathode ray tube (CRT) glass, for making new products or as an admixture to existing ones is being intensively investigated. This kind of research intensified particularly in the period after CRT TV sets and computer monitors were replaced in the market by the advanced technology of thin film transistor (TFT) and liquid crystal display (LCD) screens. Cathode ray tube glass represents a considerable part of electronic waste (e-waste). E-waste globally increases at a far higher rate than other solid waste materials. There is a possibility to recycle cathode ray tube glass and use it in the construction industry. This paper shows the test results of physical and mechanical properties of blocks and paving flags. The reference specimen was made with quartz sand, while the other product employed a combination of quartz sand and ground panel cathode ray tube glass. The glass was ground to the fraction 0.25/1.00 mm, which corresponds to quartz sand fineness. The following tests were performed: shape and dimensions, resistance to freeze/thaw and de-icing salts, water absorption, splitting tensile strength and tensile strength by bending. Special attention was paid to the tests of Böhme wear resistance, slip resistance of the top surface of CRT products using a pendulum, radioactivity and leaching. The texture of the experimental concrete products was observed by SEM (scanning electron microscopy) and analyzed. The results obtained by experimental testing unequivocally show that CRT glass can successfully be used for making concrete blocks and paving flags.

Unsaturated Polyester-Based Polymer Concrete Containing Recycled Cathode Ray Tube Glass Aggregate

Polymer concrete (PC) is a composite construction material that boasts several advantages, such as lightness, low water permeability, high resistance to corrosive environments, and chemical degradation. Consequently, it has recently attracted interest as an alternative material to the traditional ones for several civil applications. In this study, unsaturated polyester resin was considered the matrix phase of PC. Aimed to produce green PC, the commonly dispersed phase of natural aggregate was totally replaced by recycled glass aggregate (RGA) deriving from cathode ray tube (CRT) glass waste. Fine and coarse fractions of non-hazardous CRT glass were considered in different ratios. Chemical and physical analyses were carried out through XRF, particle size distribution and microstructural analysis to characterize RGA. The influence of RGA particle size and percentage on PC performance was investigated by microstructural analysis and aggregate packing, chemical resistance, water absorption, and mechanical analyses, such as bending, impact, and scratch test. Using solely the coarse fraction of RGA led to the manufacturing of a green PC with similar performance to the traditional PC and in addition lower in density. The PC quality mainly depended on the matrix crosslinking which, for PC containing fine RGA, was promoted by adding 4 wt% of silane coupling agent.

ELECTRONIC WASTE: THE PAINS AND THE GAINS

This paper presents an assessment of e-waste with respect to rate of generation, composition, risk and recycling potential. Data were extracted from published works and further analysed to provide insight into these aspects of e-waste management. Results showed that Nigeria has one of the highest per capita rate of e-waste generation (7kg/capita/year) as a result of heavy reliance on used electrical and electronic equipment as well as export of e-waste by developed countries. Television sets and personal computers constitute 55% of the total e-waste generated. Lead and copper present very high risk because of their wide application in printed circuit boards (PCB) which are used in virtually all electrical and electronic equipment and cathode ray tubes of television sets and personal computer monitors. Other metals found in e-waste include mercury, cadmium and arsenic have been implicated in severe health problems such as cancer, lung disease, renal failure and brain damage. This paper further revealed that the risk associated with improper disposal of e-waste can be reduced by recycling and re-use. E-waste from mobile phone alone has an economic potential of ₤186,000,000 or N89,000,000,000 which is equivalent to 4,886,550 barrels of crude oil. Gold component of mobile phone account for 68% of this potential revenue.

IMMOBILIZATION OF HIGH-LEADED CATHODE RAY TUBE GLASS IN FIRED CLAY BRICKS BY RECYCLING

End-of-life cathode ray tubes (CRTs) have become global problem in the pool of waste electrical and electronics owing to higher concentration of lead (Pb) and this needs urgent management in an ecofriendly manner. In this study, spent CRT glass was incorporated in clay to make burnt bricks for construction. Samples of CRT glass were collected from technicians’ workshops, manually dismantled, pulverized, milled and sieved into three particles sizes (PS), namely; 0.6mm ≤1.0mm, ≤2.0mm. The metallic composition was determined with Inductive Coupled Plasma- Optical Emission Spectrometric technique (ICP-OES). Each PS was mixed with clay at percentages ranging from 0% as control to 15% CRT and moulded using dry compression technique, dried and fired in furnace at 800 0C. Mechanical properties of fired bricks products were assessed including water absorption, linear shrinkage and compressive strength. The 4wt% CRT-clay composition for ≤0.6mm PS exhibited highest strength with low linear shrinkage and medium water absorption and was selected as optimum composition. Lead (Pb) leachability from fired CRT-glass/clay from the three particle sizes using TCLP and SPLP were within permissible limit of 5.0mg/L set by US-EPA. The total recoverable lead (Pb) from optimum test composition was 96mg/L or 96,000 mg/kg that exceeded the permissible limit. From the findings, it can be shown that the optimum composition of less than 0.6mm particle size is of good quality, durable and environmentally safe bricks that can be used for building construction works.

Material flow, economic and environmental life cycle performances of informal electronic waste recycling in a Thai community

The informal e-waste recycling sector has potential for both harmful environmental releases and environmental benefits associated with avoided emissions from recovered materials. Four household appliances (washing machine, refrigerator, Cathode Ray Tube (CRT) television, fan) were selected for a combined Material Flow Analysis and Life Cycle Assessment (LCA) analysis of their end-of-life treatment. Data collection took place in an informal e-waste recycling community in Thailand, recording the weight of materials recovered for each appliance, along with the number of each appliance recycled for one entire village. The LCA determined the avoided emissions and damages (human health, ecosystem quality, climate change, and resource use) per kg material recovered, per product, and for an entire recycling community, with a benefit of 2.7 to 25.4 kg CO2 eq avoided per product piece. Informal e-waste recycling appears relatively efficient in material recovery and economically beneficial. Recyclers recovered 93% or more of the original mass of the products. Just over 460,000 kg of waste devices were processed each year, with a net value added of 2.1 million Thai Baht. Each year, the normalized environmental net benefits amount to 0.2 DALYs for human health, 60,000 kg CO2 eq in climate change impacts, and nearly 400,000 MJ in avoided resource damages each month. Informal e-waste recycling was found to have net benefits in terms of avoided emissions, in particular due to recovery of PCBs, copper, steel and plastic with the exception of improper disposal of hazardous materials of lead in landfilled CRT screens and burned cables.

The lead removal evolution from hazardous waste cathode ray tube funnel glass under enhancement of red mud melting and synthesizing value-added glass-ceramics via reutilization of silicate resources

Waste CRT funnel glass (FG) is a typical hazardous waste produced by the electronics industry that contains toxic lead oxide, red mud (RM) is the first waste produced during alumina production. Both of these are extremely difficult to reuse. Here, we report a method to control FG waste, in which RM was used to enhance the removal of Pb from FG via a vacuum thermal process. The removed residual glass was utilized to create glass-ceramics. The results showed that RM can enhance the lead removal from waste CRT funnel glass by the vacuum thermal process. When 30% RM was added, the removal rate reached 98.54%. A significant mechanism of enhancing delead is investigated by a Fourier transform infrared (FTIR) spectrometer and X-ray photoelectron spectroscopy (XPS). The results showed that the -Pb-O-Si-O- network structure was broken by the free calcium ions of RM. Afterward, valuable glass-ceramics with tetragonal-KAlSi2O6 and triclinic-CaSiO3 crystals were synthesized using the residual glass. The Pb, Ba, Cr, and Cu leaching concentrations of the glass-ceramics were well below the regulatory limit (5 mg/L) of the CA-EPA, as measured by the toxicity characteristic leaching procedure (TCLP) test. Overall, the results indicated that RM enhanced the removal of lead during the vacuum thermal process. The synthesis of value-added glass-ceramics reutilized silicate resources from waste cathode ray tube (CRT) funnel glass and RM.

Recycling of waste cathode ray tube glass through fly ash-slag geopolymer mortar

Large amount of waste cathode ray tube (CRT) glass containing the hazardous heavy metal Pb, discarded at landfill sites without proper recycling method, poses a great threat to the environment and public health. It is urgent to develop an effective and efficient recycling method to minimize the quantity of these hazardous wastes. In the present study, recycling of waste CRT glass as fine aggregate through fly ash-slag geopolymer composite were studied. The compressive strength, alkali-silica reaction expansion (ASR expansion) and Pb leaching of fly ash-slag geopolymer mortars containing CRT glass (FSGM-CRT), considering influence of silica modulus and alkali dosage, were comprehensively studied through toxicity characteristic leaching procedure (TCLP) test, X-ray diffraction (XRD), thermogravimetry (TG), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). The results showed that the solidification mechanism of geopolymer for waste CRT glass includes not only physical encapsulation, but also chemical solidification. As the silica modulus increased, the compressive strength and the ASR expansion first increased and then decreased, and the leached concentration of Pb significantly decreased. The increased silica modulus improves the chemical binding of Pb ions by generating lead silicate as it is resulted by microstructure evolution tests. Additionally, increase of silica modulus can significantly improve the interfacial transition zone (ITZ) and the total porosity, resulting in better physical encapsulation performance on the leached Pb ions. On the contrary, higher alkali dosage can hinder the polycondensation reaction of silicate and aluminum tetrahedrons, inhibiting the polymerisation of the geopolymer mortars, thus leading to weakening of both the solidification performance and the compressive strength of FSGM-CRT. Considering combined structural and solidification performance requirements on compressive strength, ASR expansion and Pb leaching limit, the optimal alkali dosage and silica modulus for recycling CRT with geopolymer is 6% and 1.5, respectively.

The Cathode Ray Tube

The Cathode Ray Tube James Tropp After Stevens’s “Earthy Anecdote” Every time the electronsCame skittering off the filamentThey met with a magnetic field. They came skittering untilThey swerved in a swiftCircular line to the rightBecause of the field Or until they swervedIn a swift circular lineTo the leftBecause of the field. The current in the magnetReversed, shifting the fieldTo the right, to the left; Later the current was turned off,And the fieldVanished. [End Page 110] James Tropp Berkeley, California Copyright © 2022 Johns Hopkins University Press

Short glass fiber reinforced polymer concrete with addition of waste cathode-ray tube (CRT) glass

This paper describes the use of CRT glass waste for the production of polymer concrete. The CRT glass was subjected to a multistage mechanical disintegration process, in a way that allowed obtaining grains smaller than 2 mm. A set of hybrid reinforced polymer concrete was produced by using: ground CRT glass, sand and cut glass fibers 4.5 mm and 12 mm long. The influence of the volume of fibers and the length of glass fibers on the properties of polymer concrete with 30% by volume of epoxy resin, acting as a binder was described. Tests of CRT glass were carried out, among others study of chemical composition, particle size distribution and analysis of grain morphology. For polymer concrete, the flexural strength and compressive strength were determined, and the open porosity, apparent density, and water absorption were examined. The test results showed that polymer concrete with the use of milled CRT glass is a good way to manage this problematic waste. The polymer concrete has several times better than traditional concretes and significantly lower porosity and water absorption, which makes this material advantageous in applications such as the production of thin-walled products and products exposed to water and chemical attack. The addition of chopped glass fibers leads to an increase in mechanical properties and also protects the material against rapid disintegration after exceeding the maximum tresses, which is extremely important for the safety of use of the structure in the event of a failure.

Green Conversion of the Hazardous Cathode Ray Tube and Red Mud into Radiation Shielding Concrete

Green Conversion of the Hazardous Cathode Ray Tube and Red Mud into Radiation Shielding Concrete

Waste-to-Reuse Foam Glasses Produced from Soda-Lime-Silicate Glass, Cathode Ray Tube Glass, and Aluminium Dross

Aluminium dross is a hazardous industrial waste generated during aluminium production. It contains metallic oxides of aluminium and magnesium, other phases (aluminum nitride), and residues of fluxes and salts from the melting process of aluminium. Discarding this by-product is considered an environmental and economic challenge due to the high reactivity of dross with water or even air humidity. After removing the hazardous components from the as-received dross, one of the optional approaches is to incorporate the treated dross into construction materials. Dross is applied in several types of research as a secondary raw material source for alumina, clinker, cement or glass-ceramic production, but only a few papers focus on the usage of dross as a foaming agent for foams. Even fewer research are reported where dross was applied as a basic component of foam glasses. In this work, foam glasses were produced completely from waste materials: Aluminium dross, container (SLS) glass, and cathode ray tube (CRT) glass. The research holds several specificities, i.e., combining two industrial waste materials (CRT glass and dross), and adding an increased amount from the wastes. The physical and mechanical characteristics were examined with a special focus on the effect of the foam glass components on the microstructure, density, thermal conductivity, and compressive strength.

Recovery of Y and Eu from waste CRT phosphor using closed-vessel microwave leaching

• Closed-vessel microwave is effective for Y and Eu leaching from CRT phosphor. • It is energy-efficient with total energy requirement of 456.7 kJ (217 W) within 30 min. • 86.67% of Y and 100% of Eu were leached out using 2 M of H 2 SO 4 at 125 °C. • The recovery efficiency was 96.9% for Y and 86.6% for Eu as (Y 0.95 Eu 0.05 ) 2 O 3. Yttrium (Y) and europium (Eu) are critical rare earth elements (REEs) due to their high supply risk and importance for clean energy technologies. Their presence in electronic waste (e-waste) provides great potential of recovery and reuse. This study focused on recovery process of Y and Eu from waste cathode ray tube (CRT) phosphor using closed-vessel microwave leaching, followed by precipitation by oxalic acid and calcination. The effects of acid concentration and energy efficiency of closed-vessel microwave leaching were investigated. Leaching efficiency of Y and Eu was 86.67% and 100%, respectively, at the optimum operation conditions (10 g/L of solid concentration, 2 mol·L −1 of H 2 SO 4 solution, 125 °C, 30 min of leaching time). When comparing with conventional heating process, closed-vessel microwave leaching process proved to be rapid, effective and efficient for Y and Eu recovery from waste CRT phosphor. Oxalic acid precipitation and calcination recovered 96.9 ± 0.26% of Y and 86.6 ± 0.76% of Eu as the crystallized product of (Y 0.95 Eu 0.05 ) 2 O 3 .

Physical, microstructure and leaching assessments for pavement road base containing mixed steel slag and cathode ray tube glass

Physical, microstructure and leaching assessments for pavement road base containing mixed steel slag and cathode ray tube glass

A Review on Compressive Strength of Concrete Containing Waste Cathode Ray Tube Glass as Aggregates

The issue of the cathode ray tube (CRT) technology facing its end-of-time and increasing quantities across the globe has acquired the responsiveness of many researchers. The use of waste CRT glass as a construction material has fascinated them due to its significant advantage in recycling the hazardous and non-biodegradable waste CRT glass. However, lack of knowledge about the effects and features of CRT glass as a construction material could be a hindrance to the excessive utilization of waste CRT glass. Therefore, in order to establish the idea of using CRT waste glass as a more common construction material, this paper reviews several recycling techniques of CRT glass and further detail on the workability, density, and compressive strength properties of concrete and mortar using CRT glass (treated or untreated) as fine aggregates. The review showed that, generally, the use of CRT glass as a complete or partial replacement of natural sand shows a slight increase in density, workability, and concrete strength compared to conventional concrete. However, there are no clear trends that can be concluded as this review also showed that various factors influenced its performance, such as percentage replacement, particle size, lead (Pb) content, and types of admixtures.

An extensive study on the neutron-gamma shielding and mass stopping power of (70-x) CRT–30K2O–xBaO glass system for 252Cf neutron source

ABSTRACT The present study focuses on the charged-uncharged particles shielding performance of the addition of a mixed type of cathode ray tube (CRT) in a glass system that is irradiated by the 252Cf neutron source via the MCNPX simulation and analytical calculations, as well as Phy-X: PSD and SRIM software. The CRT waste glass is inserted into the glass system with (70-x) CRT–30K2O–xBaO general formula for x = 0, 10, 20 mol% that produces CG1, CG2, and CG3 glass shielding materials. Using Watt Fission Distribution (WFD) and Doppler Effect (DE) the neutron-gamma photon spectra were extracted for shielded (in the presence of the glass materials) and unshielded (in air) cases. Some calculated attenuation parameters related to the neutron deduced that CG1 is the best neutron attenuator among the selected glass samples. Moreover, by increasing the density of the glass from CG1 to CG3, the ascending trend is observed for the linear attenuation coefficient (LAC, cm−1) of the studied glass, and the best shielding competence is monitored for CG3. Furthermore, two sharp peaks are found in Zeff graphs which may be due to K-edge absorption of Ba and Pb elements and by decreasing the Pb element from CG1 to CG3 the second peak gradually becomes smooth. In addition, Mass Stopping Power/ Projected Ranges of the proton (H1) and alpha particles (He+2) are also estimated by SRIM code and findings show that CG1 can better stop proton and alpha particles in comparison with the other chosen glass structures.

Properties of Cement-Based Materials Containing Cathode-Ray Tube (CRT) Glass Waste as Fine Aggregates—A Review

Among many alternatives to replace sand in cement-based materials, cathode-ray tube (CRT) glass emerges as a suitable replacement for many reasons. This paper provides a state-of-the-art review on the use of cathode-ray tube (CRT) glass waste in cement-based concrete and mortar in accordance with PRISMA guidelines. The new aspects of the research are the literature coverage up to 2021 which would make it distinct from other articles. This review would act as a catalyst to use CRT glass waste in concrete mixtures. A total of 61 papers from literature were analyzed with emphasis on the fresh, mechanical, and durability performance of cement-based materials containing CRT glass waste as fine aggregates. The analysis revealed that the majority of the studies agreed that replacing sand with CRT glass waste increased the consistency where the low permeability of the CRT glass caused this effect. Strength of cement-based materials, on the other hand, decreased due to the weaker bond between the cement paste and the aggregates. The low water absorption of the CRT glass defined its effect on the durability properties of cement-based materials, such as drying shrinkage and water absorption capacity, leading to an improved performance. In addition, CRT glass waste activated the alkali-silica reaction in cement-based materials causing undesirable expansion. Additionally, several investigations proposed solutions to mitigate the lead leaching associated with the lead content found in the CRT glass. In general, it was assessed that CRT glass waste could be a valid component in the production of sustainable cement-based materials, especially for radiation shielding applications. The recommendations for future research are also suggested.