Critical Materials and Sustainability Flashcards
Environmental Impact of Mining
In general, the more scarce the material, the greater the impact
Waste left over after the extraction of ore (tailings) is piped to deep water but there is now concern about the effect of toxic waste on marine life
Reserves and Resources
Mineral Reserve: Fully geologically evaluated, can be mined commercially and legally with current technologies and prices
Resource Based: Natural concentration of minerals which has, or might have, potential to be a commercial commodity (includes Reserves), resource base shows variation in confidence levels or certainty of predictions
Improved mining tech: deeper, lower grades of ore, new ore types, new sources of supply
Increased carbon footprint, pollution and health
Increased prospective: improved geological understanding, developments in exploration technologies
Global transport: Bulk low-cost transport allows the economic processing of low-grade ores through economies of scale
Indium
Used as a coating over silver in making mirrors to prevent them from turning black
Now used for LCDs and touchscreen wires connecting individual pixels in cell phones
Long term, Indium will be available with intermittent price volatility
It is not mined, it is a by-product of zinc refining. It is a relatively recent discovery so there are tailings from historic extraction operations that could contain this.
There are discrepancies in yield
Discrepancies in usage prediction caused by economics and disruptive technologies: Indium was used extensively in transparent infrared (IR) reflecting coating on aircraft windows. This declined as indium prices increased and higher value applications for transparent electrodes took over
Development of modified alumina as a substitute for current usage
Definitions
Strategic material: National security, military needs, requirements during national emergencies
Critical material: Something vital, important, essential or significant, performs an essential function for which few or no satisfactory substitutes exist
Supply Risk
Combination of factors (not all independent of each other)
Scarcity: Usually geological (how much of the mineral resource exists in the lithosphere)
Location of resources: In a few locations or many?
Technical: Can we extract and process it?
Environmental and social: Can we produce it acceptably?
As we move to mining leaner ores in more difficult locations, the environmental impact increases. The dominant factor (water, energy, land use or acceptability) varies between materials.
Water Risk
Political: Political stability of countries holding resources; government policies?
Economic: Is the price acceptable?
No simple answer to what critical materials we will run out of
Critical Materials
Platinum Group Metals
Used for auto catalysis, electronics, medical applications and jewellery
Rare Earth Elements
17 elements, widespread applications. Substitutions difficult for permanent magnets, automotive catalytic converters, and medical imaging devices.
Mostly produced as a by-product of mining operations for other metals.
95% production in China
Neodymium Nd:
High-strength magnets used in turbines
90% of supply from China
Prices have doubles
Minimising Impacts
Reclamation:
Post-usage metal is widely dispersed in small concentrations, mixed with other materials
Recent and proposed initiatives include:
Collection of small quantities of materials in electronic equipment which are currently not economic to recover (assisted by WEEE Directive)
Collection of urban road sweepings to concentrate platinum group metals
Landfill mining?
Technologies for reclaiming metal
Conventional mines are much larger and the amount of metal that can be obtained in not of commercial significance
Contents heavily contaminated; separation confidence levels low
Metals have often converted into sulphides, making separation more difficult and processing more expensive
Lithium
Used in batteries
Demand for lithium has been rising steeply and now exceeds available supplies
Problem is that lithium metal isn’t being produced fast enough
Recycling:
Disassembled carefully to avoid a fire hazard
Lithium is in the cathodes, but there’s a wide range of different materials which require different reclamation processes. All are expensive, energy-intensive and use hazardous chemicals
Recycling of Li-ion batteries alone is not a currently viable solution to Li supply shortages
Legislation requiring transition to electric vehicles is moving too fast for lithium supply to keep up; there are current material shortages
Shortage of batteries may impede vehicle production
New sources of lithium needed: Urgent need to reduce or eliminate dependence on lithium
End-of-life for next-generation batteries should be a major consideration: recycling
must be economical and have low environmental impact
Low energy
Uses non-hazardous chemicals
Safe and simple procedures
Minimising Impacts
More efficient recovery from ores
Substitution: examples
Substitute materials for Indium for LCD displays
Develop technologies to remove need for platinum catalysts
Rare-earth free cars, remove need for neodymium
New generation batteries not involving lithium
Minimisation of material use: examples
Changes in design and materials: more efficient materials usage
Increase product longevity; re-use and repair
Changes in nature of product e.g. move to service and eliminate physical product (Product Service System, PSS)
Avoid non-essential applications (e.g. jewellery for platinum group metals)
More recycling
Better recovery, collection and concentration of post-use material
Could include move to another sort of PSS: eco-leasing (e.g. Li-ion batteries are leased to customer so manufacturer retains ownership and manages recycling/re-use for its products)
Better recycling (including new technologies)
Applicability and effectiveness of different measures varies between materials
