8
(unleaded) of a cathode-ray tube. Therefore, recycling technology gives emphasis to
avoid contamination and efficient extraction of lead. There are various recycling
methods to segregate the funnel glass from panel glass.
1.5.1 Gravitational-Fall Method
Cathode-ray tube facing downward is dropped from a designated height due to the
force of gravity resulting into the breaking of funnel glass by the impact of the surface. Thus, panel glass is separated from funnel glass during this method. The major
challenge with this method is achieving clear separation. This method is low cost
and simple (Herat 2008).
1.5.2 Electric-Wire Heating Method
In this method, thermal shock resulting from alternating heating and cooling is
applied by wrapping a Nichrome along the frit line of the cathode-ray tube which
results into breakage, thus separating the funnel glass from panel glass. It requires
1–3 min based on the size and type of cathode-ray tube (Lee et al. 2004). This
method is suitable for mass production due to its easy operation, high efficiency,
cost affordability, and absence of noise (Lee et al. 2004; Heart 2008). However, difficulty arises if the wire is improperly placed, the resulting creation of sharp edges
on fragmented parts.
1.5.3 Thermal Shock
In this method, both funnel and panel glass along the frit line are segregated due to
thermal shock resulting from restricted heat subsequently by cold air. This method
uses electric wire heating and quench. This method is widely used in China.
1.5.4 Laser Cutting Method
It is similar to the thermal shock method, but in this method, the laser beam is used
instead of electric wire heating followed by a spray with cold water (Yu et al. 2016).
This energy-intensive method is suitable for wide-ranging processes (Heart 2008;
Yu et al. 2016) although it is costly due to high investment. The drawbacks to this
method are challenges of cutting thick glass and its restoration after the use of laser
beam.
S. Shams
(unleaded) of a cathode-ray tube. Therefore, recycling technology gives emphasis to
avoid contamination and efficient extraction of lead. There are various recycling
methods to segregate the funnel glass from panel glass.
1.5.1 Gravitational-Fall Method
Cathode-ray tube facing downward is dropped from a designated height due to the
force of gravity resulting into the breaking of funnel glass by the impact of the surface. Thus, panel glass is separated from funnel glass during this method. The major
challenge with this method is achieving clear separation. This method is low cost
and simple (Herat 2008).
1.5.2 Electric-Wire Heating Method
In this method, thermal shock resulting from alternating heating and cooling is
applied by wrapping a Nichrome along the frit line of the cathode-ray tube which
results into breakage, thus separating the funnel glass from panel glass. It requires
1–3 min based on the size and type of cathode-ray tube (Lee et al. 2004). This
method is suitable for mass production due to its easy operation, high efficiency,
cost affordability, and absence of noise (Lee et al. 2004; Heart 2008). However, difficulty arises if the wire is improperly placed, the resulting creation of sharp edges
on fragmented parts.
1.5.3 Thermal Shock
In this method, both funnel and panel glass along the frit line are segregated due to
thermal shock resulting from restricted heat subsequently by cold air. This method
uses electric wire heating and quench. This method is widely used in China.
1.5.4 Laser Cutting Method
It is similar to the thermal shock method, but in this method, the laser beam is used
instead of electric wire heating followed by a spray with cold water (Yu et al. 2016).
This energy-intensive method is suitable for wide-ranging processes (Heart 2008;
Yu et al. 2016) although it is costly due to high investment. The drawbacks to this
method are challenges of cutting thick glass and its restoration after the use of laser
beam.
S. Shams