Geology Reference
In-Depth Information
Lastly, phosphating is a steel pretreatment providing corrosion resistance and
surface improvement which facilitates the application of spray paint on a chassis. It
involves a dilute solution of phosphoric acid mixed with zinc and iron phosphates
being sprayed on the steel surface at 45-55
C. The mixture reacts with the iron,
and forms a crystallised coat of Zn
3
(PO
4
)
2
and FeZn
2
(PO
4
)
2
, serving to prolong
the life of the vehicle by anything between 5 to 10 years. Given that phosphorus is
one of the most critical elements for the sustenance of life, prone to shortage with
no known replacement, the sustainability and the necessity of this practice must be
questioned.
Returning to the HEV specifically, in weight terms, a typical car battery pack
contains 10-15 kg of lanthanum. About 1 kg of neodymium is used in the permanent
magnets (PM). All electric motors are driven with PMs, with as of yet no possible
alternatives due to the minimal weight and space requirements. Electric bicycles
also use PM motors and batteries. Even if their power is less than 1 kW, the IEA
(2010b) projects a demand of 101 million electric bicycles by 2020.
To illustrate the seriousness of this issue, the authors use the most recognised
hybrid vehicle, the Toyota Prius.
According to Molycorp
15
, the Prius HEV of 55 kW traction motor contains per-
manent magnets with Nd;Pr;Dy and Tb in the hybrid electric motor and generator,
more than 25 micro-electric motors powered with NdFeB magnets throughout the
vehicle's power adjustable seats, windshield wipers, power windows and power steer-
ing systems. La and Ce are located in its hybrid NiMH battery, Ce in its glasses
and mirrors, Eu;Y;Ce in its liquid crystal screen, Y in its component sensors, Nd
in its headlight glass, Ce;Zr and La in its catalytic converter, whilst Ce and La
are utilised as a diesel fuel additive.
As all vehicles, not just the Prius, become steadily more electrically driven, the
need for electric storage and high power ratings increases. Plug-in hybrid vehicles
(PHEV) and electric vehicles (EV) must in turn use lithium-ion batteries instead of
NiMH ones. Gaines and Nelson (2009) estimated that the need for lithium ranges
between 3.4 and 12.7 kg for a 100 mile EV battery autonomy. Such batteries are
light and have a high energy density (0.11 to 0.30 kg/kWh). According to García-
Olivares et al. (2012) if today's entire transport fleet could be converted into EVs
using lithium ion batteries over the next thirty years, some 8 Mt of Li would be
used in the transport sector alone.
The estimated lithium resources vary considerably depending on the source -
Tahil (2008); USGS (2011b) and Gruber et al. (2011) assign 19.2 Mt, 33 Mt, and
38.68 Mt, respectively. The estimated reserves also vary with Tahil (2008) stating
4.6 Mt whilst the USGS (2011b) place them at 13 Mt.
The data provided by Gruber et al. (2011) comes from the analysis of 103 de-
posits consisting of brines, sedimentary rock or pegmatites. The highest three de-
15
http://www.molycorp.com/products/rare-earths-many-uses/advanced-vehicles. Accessed Aug.
2012.
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