10
1.6 Potential Technology for Removal of Lead from CathodeRay Tube
Lead has inimitable properties like resistance to corrosion, ductility, softness, and
malleability and therefore is widely used in the manufacturing of batteries, solder,
and X-ray shielding (Yu et al. 2016). It is quite difficult to extract a good amount of
lead under normal pressure and temperature (Miyoshi et al. 2004) which comprises
of O-Si-O- network and/or partly -O-Si-O-Pb-O- network encapsulated in the fissure of the glass assembly (Sasai et al. 2008). Therefore, to perform better lead
extraction, importance is given on the selection of extraction lead methods by disintegrating the glass assembly. The well-known lead recovery process is as follows:
1.6.1 Pyrometallurgical Process
The pyrometallurgical process has been used successfully by various researchers to
extracted lead from waste cathode-ray tube (Yot and Mear 2011; Okada and
Yonezawa 2013, 2014; Mingfei et al. 2016). This process is used to remove lead and
other metals by adding sodium carbonate powder (fusion agent), sodium sulfide
(catalytic agent), and carbon powder as reducing agent with lead removal efficiency
of 94% (Hu and Hui 2018) as shown in Fig. 1.5. Besides, Lu et al. (2013) used
metallic iron for thermal reduction to extract lead with 99% efficiency from cathoderay tube funnel glass. Addition of Na 2 CO 3 also assists in the reduction process by
restricting temperature below 1000 °C, to avoid lead evaporation (Okada and
Yonezawa 2013). Recently Okada et al. (2015), using reducing and oxidizing condition, extracted lead from cathode-ray tube funnel glass dissolved into hydrochloric
acid. Xing and Zhang (2011) used the pyrometallurgical process to extract nanoparticles of lead using a carbon-reducing agent, in a vacuum of 500–2000 Pa, with a
temperature of 1000 °C for 2 h (Xing and Zhang 2011).
Table 1.2 Available technology for removal of coatings
Technology
Brief description
References
Wet-scrubbing
method
Water and coatings scrubbed off from disintegrated
cathode-ray tube glass positioned in a tumbling mill
Lee et al.
(2004)
Ultrasonic
method
Disintegrated cathode-ray tube glass is submerged into
acid and water and immersed in an ultrasonic device for
a certain time
Ezrat and
Zhang (2014)
Sandblasting
method
Air jet under high pressure ensures blasting of small steel
balls onto the glass surface
Heart (2008)
Vacuum-suction
method
Slack finishes from the panel glass are sucked using
surface vacuum-suction device
Heart (2008)
S. Shams
1.6 Potential Technology for Removal of Lead from CathodeRay Tube
Lead has inimitable properties like resistance to corrosion, ductility, softness, and
malleability and therefore is widely used in the manufacturing of batteries, solder,
and X-ray shielding (Yu et al. 2016). It is quite difficult to extract a good amount of
lead under normal pressure and temperature (Miyoshi et al. 2004) which comprises
of O-Si-O- network and/or partly -O-Si-O-Pb-O- network encapsulated in the fissure of the glass assembly (Sasai et al. 2008). Therefore, to perform better lead
extraction, importance is given on the selection of extraction lead methods by disintegrating the glass assembly. The well-known lead recovery process is as follows:
1.6.1 Pyrometallurgical Process
The pyrometallurgical process has been used successfully by various researchers to
extracted lead from waste cathode-ray tube (Yot and Mear 2011; Okada and
Yonezawa 2013, 2014; Mingfei et al. 2016). This process is used to remove lead and
other metals by adding sodium carbonate powder (fusion agent), sodium sulfide
(catalytic agent), and carbon powder as reducing agent with lead removal efficiency
of 94% (Hu and Hui 2018) as shown in Fig. 1.5. Besides, Lu et al. (2013) used
metallic iron for thermal reduction to extract lead with 99% efficiency from cathoderay tube funnel glass. Addition of Na 2 CO 3 also assists in the reduction process by
restricting temperature below 1000 °C, to avoid lead evaporation (Okada and
Yonezawa 2013). Recently Okada et al. (2015), using reducing and oxidizing condition, extracted lead from cathode-ray tube funnel glass dissolved into hydrochloric
acid. Xing and Zhang (2011) used the pyrometallurgical process to extract nanoparticles of lead using a carbon-reducing agent, in a vacuum of 500–2000 Pa, with a
temperature of 1000 °C for 2 h (Xing and Zhang 2011).
Table 1.2 Available technology for removal of coatings
Technology
Brief description
References
Wet-scrubbing
method
Water and coatings scrubbed off from disintegrated
cathode-ray tube glass positioned in a tumbling mill
Lee et al.
(2004)
Ultrasonic
method
Disintegrated cathode-ray tube glass is submerged into
acid and water and immersed in an ultrasonic device for
a certain time
Ezrat and
Zhang (2014)
Sandblasting
method
Air jet under high pressure ensures blasting of small steel
balls onto the glass surface
Heart (2008)
Vacuum-suction
method
Slack finishes from the panel glass are sucked using
surface vacuum-suction device
Heart (2008)
S. Shams