F6 Flashcards
Different uses of Metals
*In the Construction Industry
*In electronics
*In medicine
*Machinery, Refractory and
Automobiles
*Decorative products
*Other Uses, for example
catalys
Metal life cycle
First, the raw materials, either iron ore or scrap
iron (depending on the process), are converted
into molten steel. The ore-based process uses a
blast furnace or smelter and the scrap-based
process uses an electric arc furnace.
Next, the molten steel is poured and solidified in
a continuous caster. This produces semi-finished
products. These can be either slabs, which have
a rectangular cross-section, blooms or
billets,
which have a square cross-section.
Lastly, these blank products are used to form a
finished product. Depending on the particular
geometries required, some will need to undergo
heat treatment to achieve particular mechanical
properties.
Why the production of steel produce so much CO2?
The steel industry contributes nearly 8% of global CO2 emissions
1 ton steel generate 2 tons CO2
How to reduce the CO2 emission during the steel production?
- Non-fossil reductants
- Electrification in primary
synthesis - Use of higher scrap
fractions in secondary
synthesis.
Rebound effect
clean energy need steel to construct which is not good for the enviroment
Sustainability of Aluminum
Advantages and disadvantages of using aluminum scrap
The advantage of aluminum in terms of scrap use is that up to
95% energy can be saved by melting scrap instead of making it
from oxides via electrolysis, because of the metal’s low melting
point.
There is also an aluminum-specific disadvantage, namely its low
solubility for other elements. This means that most of the
impurity elements introduced into the material by the scrap
become intermetallic phases and these can deteriorate the
materials’ mechanical and corrosion properties.
Sustainability of Copper
Copper is the key metal for the electrification of transport, energy supply, and industry
The total demand in 2010 of about 16 Mt of copper is expected to grow to 23 Mt in 2030, at greenhouse gas
emissions of approximately 87 kt CO2 equivalent emissions, depending on the technologies used
Metals The life cycle of aluminum
Strip minded
Grinding and chemical processing results in pure
aluminum hydroxide. The waste material, highly
caustic red mud, is often disposed of in badly
managed conditions, with considerable risks for
local ecosystems. The aluminum hydroxide is
subsequently turned into aluminum oxide at
1000oC, which is dissolved in highly corrosive
Na3AlF6 at 960oC for electrochemical reduction to
the metal.
The tapped metal is then, after alloying, cast into
ingots or rolled into sheets to be sent to product
manufacturers.
The entire process, but especially the electrochemical
processing, is extremely energy intensive; greenhouse
gas emissions are therefore high.
Also, as an undesired result of this process,
highly stable perfluorocarbons are formed, lasting
for over 10,000 years.
➢ Light weight,
➢ High strength,
➢ Corrosion resistance
Applications varying from packaging to domestic
products, transportation, and structural elements
in buildings.
➢ Wrought alloys (Low concentration alloying element,
ductility for rolling and extrusion process)
➢ Cast alloys
Good properties
End of life
Production from mining
* Energy intensive processing
* High greenhouse gas emission
“secondary” (recycled) metal and primary aluminum
➢ It saves 95% of the energy compared to making
aluminium from its raw materials (known as
primary production).
➢ It saves 95% of the greenhouse gas emissions
compared to the primary, or smelting, process.
➢ It saves raw materials. It reduces the space
needed for landfill – where waste is buried in holes
in the ground.
Design the products with the consideration of recycling at
end of life
Design for customer/user repair
Modularity
- Easy to repair
- Profitable
- Recyclable
Metal recycling - Lithium ion battery
*Lithium
*Nickel
*Cobalt
*Manganese
*Graphite
*Iron
*Copper
*aluminum
*Electrolyte that is usually flammable
Three main methods recycling lithium ion batteries:
pyrometallurgy
* Energy-intensive, consuming large
amounts of fossil fuels, and generates
considerable amounts of hazardous
fluoride and carbon dioxide emissions.
* Only the metals (Ni/Co/Fe/Li/Mn) are
recovered, the graphite and binder are
destroyed
disassemble
* Not applicable to all batteries
* High requirement for precise and
discrete separation
hydrometaalurgy
* Dissolving metals in liquids
* Not pure metal, but metal salts
* Lower energy consumption
* Generate large amount of sulfate
wastes, pose environmental and
public health risks.
* Less efficient to recover lithium
Lithium ion battery recycling: electro-hydrometallurgy
Electro-hydrometallurgy is an innovative recycling method that merges the principles of
hydrometallurgy and electrochemistry to recover valuable metals from lithium-ion batteries.
Three most commonly recycled alloys
- Steel (40% recycled)
- Aluminum alloy
- Brass
Aluminum can (95% recycled)
Electronics (???)
Multi-metal recycling problem
- Nanoscrap
- Difficult separation
- Mutual poisoning problem
- Not profitable
- Polymetallurgica
metal - end of life recovery (un-recyclable)
ITO is Indium Tin Oxide, used in modern devices that
manipulates ambient light
The ITO glass is an expensive material because of the indium mineral, but this is not the biggest problem. The biggest challenge is the shortage
expected to take place in a few years because indium is a rare mineral.
Much of the indium mineral reservations are located in China, which controls the exporting and marketing demand of this material.
It has a good response time to conduct electricity and an appropriate transparency for the emission of light.
Recycling
Standard recycling: Standard recycled metallurgical products the quality of the product should not be
diminished when using materials from recycling processes.
Downcycling: downcycling is the transformation of a product into one of lower quality. In this process, waste
products can be used for the synthesis of less pure and less valuable products or they can be broken down into
more basic chemical components; example: titanium chips from aerospace applications into titanium oxide for
wall-painting.
Upcycling: the waste products undergo material upgrading and thus attain a higher value than before. The raw
material undergoes little change and remains relatively true to its original form, saving energy and achieving a
high degree of sustainability. Example, solid-state electrolysis process for upcycling aluminum scrap.
Summary
Challenges in recycling of mixed metals – impurities
The use of higher scrap levels may result in the introduction of undesirable
impurity levels into the steel.
Some elements intruding from scrap are particularly harmful (such as Cu,
Pb, Sn and Zn), potentially affecting the performance of advanced high-
strength steels
Copper, aluminum, and iron should not be mixed, as they are not
compatible with each other in recycling. This implies for instance that
copper cannot be recovered from an iron melt or aluminum melt. So, mixed
fragments of these metals can never be fully recycled
Identify your product’s metals and recycling streams
➢ Make a table of the metals in your product (On the paper) and categorize them by the main
metal recycling streams of Copper, aluminum, iron/steel, and lead.
➢ What are your product’s most important metals to recycle at end-of-life? Are they the ones
with the most mass used in the product, or are some metals used less but still more
important because they have much higher environmental impact, like gold?
➢ Choose one product, and then google the metals used in the product.
➢ Ideate more recyclable materials choices (alternative metals/materials)
Metal application as Gas barrier in food packaging
However, there are challenges with
recycling food packaging materials.
Packaging waste represents approx.
15% of municipal waste.1
Barrier properties include permeability of gases (such as O2, CO2, and N2), water vapour, aroma compounds and light.
These are vital factors for maintaining the quality of packaged foods
Single Layer Graphene has excellent barrier
properties
Sustainable solution: protection (longevity) for metals
Graphene coating can protect the metal from O2, and inhibit the metal from corrosion
Bulk graphite works the best in humid
environments but fails to provide low
friction and wear in inert, dry, or vacuum
environments
