74
indium due to its scarcity and high consumption of liquid crystal display production
which account for 70% of produced indium worldwide (Zhang et al. 2015b).
Most common recycling technique from waste liquid crystal display recycling
includes dismantling which involves the removal of hazardous materials followed
by removal of indium and valuable materials. Below is a recommended industrial
flowchart for separation of indium as a precipitate from liquid crystal display panels
as shown in Fig. 4.9 (Ruan et al. 2012):
4.3.3 Computers, Notebooks and Laptops
Advancement in the Electronic-waste handling of computers shows that masses of
computers reduce with time which leads to a reduction of computer Electronicwaste but increases the complexity of metals extraction (Ravi 2012). Computers
have an average lifespan of 3 years. Also, copper is considered one of the most valuable metals in obsolete computers stored in printed wiring boards (PWBs) where the
separation process involves crushing, grinding and grain-level screening achieving
more than 80% process efficiency (Li and Huang 2015). Computers form more than
38% of total annual Electronic-waste produced and are considered the most valuable category in Electronic-waste due to high metal content (Petridis et al. 2016).
4.3.4 Cell Phones and Smartphones
Cell phones account for nearly 17% of Electronic-waste, while only 3% of global
mobile phones are recycled (Li et al. 2017). Lithium ions are considered the most
valuable material available in batteries of smartphones (Li et al. 2014). Cell phones
Liquid crystal
display screen
input
Stage 1: Manual
sorting and
separation
Stage 2: Solvent
extraction
Mass : 1.0 kg
Mass : 0.5-0.6 kg
· Lliquid crystal display
polymer frame
· Connectors
· Diffusive sheets
· Adhesives
· Reflective sheet
Unrecyclable components: 0.4
Polirized film : 0.1 kg
Stage 3: Material
reduction
Mass
: 0.4 kg
Stage 4: Acid
leaching using
sulphuric acid
Mass
: 0.4 kg
Stage 5: Indium
precipitation
Mass
: 0.3 kg
Indium precipitation
: 0.3 kg
Fig. 4.9 Mass balance of indium recovery from liquid crystal displays
M. Aboughaly and H. A. Gabbar
indium due to its scarcity and high consumption of liquid crystal display production
which account for 70% of produced indium worldwide (Zhang et al. 2015b).
Most common recycling technique from waste liquid crystal display recycling
includes dismantling which involves the removal of hazardous materials followed
by removal of indium and valuable materials. Below is a recommended industrial
flowchart for separation of indium as a precipitate from liquid crystal display panels
as shown in Fig. 4.9 (Ruan et al. 2012):
4.3.3 Computers, Notebooks and Laptops
Advancement in the Electronic-waste handling of computers shows that masses of
computers reduce with time which leads to a reduction of computer Electronicwaste but increases the complexity of metals extraction (Ravi 2012). Computers
have an average lifespan of 3 years. Also, copper is considered one of the most valuable metals in obsolete computers stored in printed wiring boards (PWBs) where the
separation process involves crushing, grinding and grain-level screening achieving
more than 80% process efficiency (Li and Huang 2015). Computers form more than
38% of total annual Electronic-waste produced and are considered the most valuable category in Electronic-waste due to high metal content (Petridis et al. 2016).
4.3.4 Cell Phones and Smartphones
Cell phones account for nearly 17% of Electronic-waste, while only 3% of global
mobile phones are recycled (Li et al. 2017). Lithium ions are considered the most
valuable material available in batteries of smartphones (Li et al. 2014). Cell phones
Liquid crystal
display screen
input
Stage 1: Manual
sorting and
separation
Stage 2: Solvent
extraction
Mass : 1.0 kg
Mass : 0.5-0.6 kg
· Lliquid crystal display
polymer frame
· Connectors
· Diffusive sheets
· Adhesives
· Reflective sheet
Unrecyclable components: 0.4
Polirized film : 0.1 kg
Stage 3: Material
reduction
Mass
: 0.4 kg
Stage 4: Acid
leaching using
sulphuric acid
Mass
: 0.4 kg
Stage 5: Indium
precipitation
Mass
: 0.3 kg
Indium precipitation
: 0.3 kg
Fig. 4.9 Mass balance of indium recovery from liquid crystal displays
M. Aboughaly and H. A. Gabbar