191
Also, Song and Li (2014) assessed how metals in E-waste cause environmental
impact in China. The study revealed the existence of soil, air, water, and plant contamination as well as the accumulation of metals in crops like rice. The concentrations of copper (Cu), mercury (Hg), chromium (Cr), and lead (Pb) were extremely
high, compared with the maximum permitted values.
10.3.2.2 The Elements Present in Electrical and Electronic Equipment
Umicore (2016) considers printed circuit boards (PCB) as deposits of metals suitable for urban mining since the concentration of metals they contain is higher than
the values obtained through primary mining. For instance, recycling of 1 ton of
computer boards produces 250 g of gold (Au).
For the sake of comparison, 1 ton of ore contains 1.5 g of gold, while the amount
of the metal in 1 ton of printed circuit boards and 1 ton of cell phones is between
150 g and 200 g and 250 g and 300 g, respectively. For Nicolai (2016), it would be
necessary to process 60 tons of gold ore to obtain the equivalent amounts of the
metal. In turn, copper levels obtained from direct mining are below 1%, while the
amounts of the metal in printed circuit boards are between 15% and 18%, even
though a recent study showed that it is possible to obtain as much as 22% of copper
from this component (da Silveira et al. 2016; Umicore 2016).
For Wen et al. (2015), primary sources of copper and iron may be effectively
replaced by secondary sources of the metals. It has been estimated that replacement
rates for copper and iron will increase by 19.6% and 48.8%, respectively, between
2020 and 2040. The authors also claim that the potential exploration of primary
resources in China will continue to grow in the same period, despite the increasing
importance of recycling E-waste as a source of metals from secondary sources for
the country’s economy.
Research shows that common metals such as copper and precious metals like
rare earth elements may be extracted from E-waste (Palmiere et al. 2014). Rare
earth elements are difficult to extract and create mining hazards due to the presence
of radioactive elements such as uranium (U) in ores, especially when extraction
methods are not carried out properly (Rare Element Resources 2016).
Also, each ton of rare earth elements generates approximately 8.5 kg of fluorine
and 13 kg of dust. The production of concentrated rare earth elements generates
75 kg of acid effluents, between 9600 m
3
and 12,000 m
3
of gas containing sulfuric
acid and sulfur dioxide, in addition to 1 ton of radioactive waste (Tunsu et al. 2015).
Moreover, rare earth elements sometimes are present in continuous ore bodies,
which means that it is necessary to mine large areas to obtain these elements (Tunsu
et al. 2015). Ayres and Peiró (2013) claim that rare earth elements are never found
at high concentrations in the environment. On the contrary, they occur as contaminants or trace elements in ores of elements called attractor metals, to which they are
chemically similar. In rare earth elements, the attractor metal is iron. Other rare
metals are found in copper (Cu), lead (Pb), nickel (Ni), or zinc (Zn) ores. Attractor
metals are mined in large amounts, like iron (Fe), aluminum (Al), copper (Cu),
10 E-waste Management and the Conservation of Geochemical Scarce Resources
Also, Song and Li (2014) assessed how metals in E-waste cause environmental
impact in China. The study revealed the existence of soil, air, water, and plant contamination as well as the accumulation of metals in crops like rice. The concentrations of copper (Cu), mercury (Hg), chromium (Cr), and lead (Pb) were extremely
high, compared with the maximum permitted values.
10.3.2.2 The Elements Present in Electrical and Electronic Equipment
Umicore (2016) considers printed circuit boards (PCB) as deposits of metals suitable for urban mining since the concentration of metals they contain is higher than
the values obtained through primary mining. For instance, recycling of 1 ton of
computer boards produces 250 g of gold (Au).
For the sake of comparison, 1 ton of ore contains 1.5 g of gold, while the amount
of the metal in 1 ton of printed circuit boards and 1 ton of cell phones is between
150 g and 200 g and 250 g and 300 g, respectively. For Nicolai (2016), it would be
necessary to process 60 tons of gold ore to obtain the equivalent amounts of the
metal. In turn, copper levels obtained from direct mining are below 1%, while the
amounts of the metal in printed circuit boards are between 15% and 18%, even
though a recent study showed that it is possible to obtain as much as 22% of copper
from this component (da Silveira et al. 2016; Umicore 2016).
For Wen et al. (2015), primary sources of copper and iron may be effectively
replaced by secondary sources of the metals. It has been estimated that replacement
rates for copper and iron will increase by 19.6% and 48.8%, respectively, between
2020 and 2040. The authors also claim that the potential exploration of primary
resources in China will continue to grow in the same period, despite the increasing
importance of recycling E-waste as a source of metals from secondary sources for
the country’s economy.
Research shows that common metals such as copper and precious metals like
rare earth elements may be extracted from E-waste (Palmiere et al. 2014). Rare
earth elements are difficult to extract and create mining hazards due to the presence
of radioactive elements such as uranium (U) in ores, especially when extraction
methods are not carried out properly (Rare Element Resources 2016).
Also, each ton of rare earth elements generates approximately 8.5 kg of fluorine
and 13 kg of dust. The production of concentrated rare earth elements generates
75 kg of acid effluents, between 9600 m
3
and 12,000 m
3
of gas containing sulfuric
acid and sulfur dioxide, in addition to 1 ton of radioactive waste (Tunsu et al. 2015).
Moreover, rare earth elements sometimes are present in continuous ore bodies,
which means that it is necessary to mine large areas to obtain these elements (Tunsu
et al. 2015). Ayres and Peiró (2013) claim that rare earth elements are never found
at high concentrations in the environment. On the contrary, they occur as contaminants or trace elements in ores of elements called attractor metals, to which they are
chemically similar. In rare earth elements, the attractor metal is iron. Other rare
metals are found in copper (Cu), lead (Pb), nickel (Ni), or zinc (Zn) ores. Attractor
metals are mined in large amounts, like iron (Fe), aluminum (Al), copper (Cu),
10 E-waste Management and the Conservation of Geochemical Scarce Resources