Removal of lead from cathode ray tube funnel glass by chloride volatilization

Grause, Guido; Yamamoto, Nozomi; Kameda, Tomohito; Yoshioka, Toshiaki

doi:10.1007/s13762-013-0286-0

Cited by 37 publications

(12 citation statements)

References 24 publications

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“…The lead content was determined by ICP-AES after dissolving the residue in a mixture of conc. nitric acid, fluoric acid (46 wt% HF in water), and H 2 O 2 [8].…”

Section: Tube Reactor Experimentsmentioning

confidence: 99%

“…Among the methods used for lead removal [4][5][6], the volatilization of lead chloride (PbCl 2 ) recently showed promising results [7][8][9]. By the addition of a chlorination agent (i.e., CaCl 2 , NaCl, poly(vinyl chloride) (PVC)), lead is separated from the glass matrix as PbCl 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Previously, we investigated the removal of lead from CRT glass using CaCl 2 and NaCl [8] and the combination of PVC and Ca(OH) 2 [9]. This time, we want to shed light on the reactions that result in lead volatilization and compare them with those observed in crystalline and amorphous PbSiO 3 .…”

Section: Introductionmentioning

confidence: 99%

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Thermogravimetric Investigation of the Lead Volatilization from Waste Cathode-Ray Tube Glass

2016

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Abstract:The treatment of lead-containing cathode-ray tube (CRT) glass is an important environmental issue. One approach is the removal of lead by chloride volatilization. In the present work, the reaction of CRT glass with PVC as the chlorinating agent and Ca(OH) 2 as the chlorine absorber was investigated by thermogravimetric analysis (TGA) in air. Seven reaction steps occurring at different temperatures were identified as dehydrochlorination of PVC/HCl absorption, CO 2 absorption, Ca(OH) 2 dehydration, PVC derived char oxidation, PbCl 2 formation and volatilization, CaCO 3 decarbonation, and CaCl 2 volatilization. Kinetic analysis of the PbCl 2 volatilization showed that the reaction of CRT glass during TGA resembles that of amorphous PbSiO 4 , while the reaction in the tube reactor was similar to that of crystalline PbSiO 4 . Crystallization accelerates PbCl 2 volatilization, and it might be advantageous for lead removal to crystallize the glass deliberately before or during treatment in order to reduce processing time and increase efficiency.

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“…The lead content was determined by ICP-AES after dissolving the residue in a mixture of conc. nitric acid, fluoric acid (46 wt% HF in water), and H 2 O 2 [8].…”

Section: Tube Reactor Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermogravimetric Investigation of the Lead Volatilization from Waste Cathode-Ray Tube Glass

2016

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“…The main purpose of this research is to investigate the feasibility of using chlorine-based metallurgy technique for lead recovery to develop an environmental benign process for waste CRT funnel glass disposal. In a previous report, [23] a separation rate of 80% for lead from funnel glass was achieved through chlorinating volatilization process. Comparatively, lead separation rate of >99% was reached in this work by applying chlorinating volatilization process in vacuum system.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of lead recovery efficiency from waste CRT funnel glass by chlorinating volatilization process

Erzat

Zhang

2014

Environmental Technology

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The current study was carried out to develop a novel process, namely chloride volatilization procedure for lead recovery from waste cathode ray tube (CRT) funnel glass. In the recovery system, the glass powder was first compressed into cylindrical pellet homogeneously with chlorinating agents, and then subjected to thermal treatment for solid-phase reaction. In this case, lead could be easily released from the silicon oxide network of the glass and it was recovered in the form of PbCl 2 . It was found that CaCl 2 was the most effective chlorinating agent, and the optimum operation temperature, holding time and system pressure were 1000 • C, 2 h, 600 ± 50 Pa, respectively. The evaporated PbCl 2 could be easily recovered by a cooling device. The evaporation ratio of lead from waste CRT was 99.1% and the purity of the recovered PbCl 2 product was 97.0%. The reaction routes and lead recovery mechanisms of the process were identified. This study provides an efficient and practical process for waste CRT funnel glass detoxification and recycling.

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“…The above methods focused on reducing the lead content in waste CRT glass through acid leaching method, but other metals such as Ba and Mg are leached simultaneously. Other technologies are also developed, such as mechanochemical process (Birke et al, 2004;Sasai et al, 2008;Guo et al, 2010;Yuan et al, 2013aYuan et al, , 2013b, the self--propagating process (Chen et al, 2009), the reduction process by reaction with silicon carbide and titanium nitride (Yot and Méar, 2009), the chloride volatilization (Grause et al, 2014), etc. However, these techniques in the process have some disadvantages, such as low lead recovery, low level of comprehensive utilization, technical constraint, and economic costs.…”

Section: Introductionmentioning

confidence: 99%

Removal of lead from cathode ray tube funnel glass by generating the sodium silicate

Zhao

Zhang

2014

Journal of the Air & Waste Management Association

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In the disposal of electronic waste, cathode ray tube (CRT) funnel glass is an environmental problem of old television sets. Removal of the lead from CRT funnel glass can prevent its release into the environment and allow its reuse. In this research, we reference the dry progress productive technology of sodium silicate, the waste CRT glass was dealt with sodium silicate frit melted and sodium silicate frit dissolved. Adding a certain amount of Na 2 CO 3 to the waste CRT glass bases on the material composition and content of it, then the specific modulus of sodium silicate frit is obtained by melting progress. The silicon, potassium and sodium compounds of the sodium silicate frit are dissolved under the conditions of high temperature and pressure by using water as solvent, which shows the tendency that different temperature, pressure, liquid-solid ratio and dissolving time have effect on the result of dissolving. At 175°C(0.75MPa), liquid-solid ratio is 1.5:1, the dissolving time is 1h, the dissolution rate of sodium silicate frit is 44.725%. By using sodium sulfide to separate hydrolysis solution and to collect lead compounds in the solution, the recovery rate of lead in dissolving reached 100% and we can get clean sodium silicate and high purity of lead compounds. The method presented in this research can recycle not only the lead but also the sodium, potassium and other inorganic minerals in CRT glass and can obtain the comprehensive utilization of leaded glass.Implications: Waste cathode ray tube (CRT) funnel glass has become a serious environmental problem throughout the world. However, some techniques in the processing of CRT waste have disadvantages such as low lead recovery, low level of comprehensive utilization, technical constraint, economic costs, and other factors, so the actual practical application is still not possible. Therefore, in order to solve lead pollution existing in the waste CRT glass and to solve resource utilization problems, it is necessary to develop a waste CRT process technology that is friendly to environment, cost-saving, and feasible.

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Removal of lead from cathode ray tube funnel glass by chloride volatilization

Cited by 37 publications

References 24 publications

Thermogravimetric Investigation of the Lead Volatilization from Waste Cathode-Ray Tube Glass

Thermogravimetric Investigation of the Lead Volatilization from Waste Cathode-Ray Tube Glass

Evaluation of lead recovery efficiency from waste CRT funnel glass by chlorinating volatilization process

Removal of lead from cathode ray tube funnel glass by generating the sodium silicate

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