2
cathode-ray tube is further having a major challenge due to its hazardous characteristics resulting from the composition of glass used in cathode-ray tubes. There are
various recycling technologies available to extract toxic lead from funnel glass of
cathode-ray tube. This chapter explores the status of cathode-ray tube, disposal, and
environmental issues followed by potential challenges of segregating funnel and
panel glass of cathode-ray tube. Separation of funnel and panel glass from the
cathode- ray tube based on open-loop and closed-loop process is discussed with pros
and cons. Cathode-ray tube glass-ceramic brick and concrete, vitrification glass to
stabilize nuclear waste, and fluxing materials such as silica flux are gaining momentum on the reuse of cathode-ray tube under closed-loop process. The diamond cutting method for segregation of funnel glass from panel glass is highly recommended
among the various potential segregation technologies available due to its vacuum
adsorption and dust recovery capacity, automatic edge searching, and laser positioning. The study finds that emerging technology using furnace and chemicals for
extraction of toxic lead from the cathode-ray tube is a promising method for management of recycling in an environmentally sustainable way without any residual
waste.
Keywords Cathode-ray tube · Closed-loop process · Frit · Funnel glass · Lead ·
Open-loop process · Panel glass · Recycling · Television · Waste
1.1 Introduction
Cathode-ray tube (CRT) used as a display unit for television and computer monitor
has become obsolete with the arrival of liquid-crystal display (LCD) screens, i.e.,
lead (Pb) in the cathode-ray tube is replaced by the introduction of mercury (Hg) in
liquid-crystal display. Each cathode-ray tube contains several leaded glasses, which
is quite heavy and requires special handling procedures for safety and regulations.
Even when the glass is processed properly, its low value and other market limitations make it difficult to recycle into new products. The funnel and panel glass
(Fig. 1.1) extracted from the old cathode-ray tube was extensively used to produce
new cathode-ray tube for television and computer monitor using closed-loop recycling system almost 15 years ago. Hence, closed-loop recycling system segregated
the glass from ferrous and nonferrous metals, oxides, phosphor, and dust efficiently
and thus provided necessary assistance to the manufacturers of the cathode-ray tube
in the past. The emergence of lightweight, space-saving, and energy-efficient lightemitting diode (LED) and plasma screens has significantly reduced the demand for
new cathode-ray tube used in television and computer monitor, as cathode-ray tube
consumes a lot more space due to its enormous size and heavyweight (He and Xu
2014; Yamashita et al. 2010). Some cathode-ray tube glass recyclers are reluctant to
dispose of a cathode-ray tube and rather stockpiling cathode-ray tube glass due to
the high cost of disposal and negative economic incentives. This stockpiling of
cathode- ray tube possesses a great challenge to environmental pollution (soil and
S. Shams
cathode-ray tube is further having a major challenge due to its hazardous characteristics resulting from the composition of glass used in cathode-ray tubes. There are
various recycling technologies available to extract toxic lead from funnel glass of
cathode-ray tube. This chapter explores the status of cathode-ray tube, disposal, and
environmental issues followed by potential challenges of segregating funnel and
panel glass of cathode-ray tube. Separation of funnel and panel glass from the
cathode- ray tube based on open-loop and closed-loop process is discussed with pros
and cons. Cathode-ray tube glass-ceramic brick and concrete, vitrification glass to
stabilize nuclear waste, and fluxing materials such as silica flux are gaining momentum on the reuse of cathode-ray tube under closed-loop process. The diamond cutting method for segregation of funnel glass from panel glass is highly recommended
among the various potential segregation technologies available due to its vacuum
adsorption and dust recovery capacity, automatic edge searching, and laser positioning. The study finds that emerging technology using furnace and chemicals for
extraction of toxic lead from the cathode-ray tube is a promising method for management of recycling in an environmentally sustainable way without any residual
waste.
Keywords Cathode-ray tube · Closed-loop process · Frit · Funnel glass · Lead ·
Open-loop process · Panel glass · Recycling · Television · Waste
1.1 Introduction
Cathode-ray tube (CRT) used as a display unit for television and computer monitor
has become obsolete with the arrival of liquid-crystal display (LCD) screens, i.e.,
lead (Pb) in the cathode-ray tube is replaced by the introduction of mercury (Hg) in
liquid-crystal display. Each cathode-ray tube contains several leaded glasses, which
is quite heavy and requires special handling procedures for safety and regulations.
Even when the glass is processed properly, its low value and other market limitations make it difficult to recycle into new products. The funnel and panel glass
(Fig. 1.1) extracted from the old cathode-ray tube was extensively used to produce
new cathode-ray tube for television and computer monitor using closed-loop recycling system almost 15 years ago. Hence, closed-loop recycling system segregated
the glass from ferrous and nonferrous metals, oxides, phosphor, and dust efficiently
and thus provided necessary assistance to the manufacturers of the cathode-ray tube
in the past. The emergence of lightweight, space-saving, and energy-efficient lightemitting diode (LED) and plasma screens has significantly reduced the demand for
new cathode-ray tube used in television and computer monitor, as cathode-ray tube
consumes a lot more space due to its enormous size and heavyweight (He and Xu
2014; Yamashita et al. 2010). Some cathode-ray tube glass recyclers are reluctant to
dispose of a cathode-ray tube and rather stockpiling cathode-ray tube glass due to
the high cost of disposal and negative economic incentives. This stockpiling of
cathode- ray tube possesses a great challenge to environmental pollution (soil and
S. Shams