Future Mineral Supplies Flashcards
Improvement in exploratory techniques
- Better remote sensing image resolution
On newer satellites—> more pixels
Multispectral sensors detect gr8er range wavelengths if visable and Infared light - ^ detailed info on mineral composition of earth surface. - Portable field equipment- lab equipment lighter, more pwrful batteries, energy consumption reduced.
Portable equip available for infared spectroscopy, X-ray fluorescence + radiation detection. Save time as results available immediately, no longer wait for lab results.
Mechanism
Deep vs open cast
Deep - machines where too hot/ dangerous for ppl
Open - larger machinery - overburden and minerals extracted quicker + cost effective —> allow rlly deep mined to b dev.ed w out high energy inputs and high temps
Exploitation of low-grade deposits
Normal method remove metal from ore
is two smelt it
Less pure —> ^ energy —> less economically viable
New methods needed to exploit low grade ore include
Bioleaching
Phytomining
Rare earth metals
Polymer absorbtion
Exploitation of low-grade deposits
Bioleaching
Use living organisms to extract metals from ores
Example
Acidophiluc bacteria used extract copper, zinc, lead, gold from low grade ores - bacteria oxidise sulfide ores — produce sulfuric acid which dissolved metals
Metal solution separated by electrolysis / carbon filters
Exploitation of low-grade deposits
Phytomining
Plants absorb metal ions from soil or water - harvested incinerated - metals in ash dissolved by acids, separated by electrolyisis
Exploitation of low-grade deposits
Iron displacement
Reactivity Iron > copper
So iron displace copper ions from solution.
Solid iron into solution as copper ions deposited as solid copper metal which collected.
Exploitation of low-grade deposits
Leachate collection
Rainwater percolating soil heap dissolves soluble metal ions. Draining leachate recirculated through spoil heap ^ conc ions in solution until high enough to be extracted by electrolysis
Exploitation of low-grade deposits
Rare earth metals
Used electrical appliances. Limited deposits - most China - chem separation complicated —> chem wastes.
New techniques eg bacteria absorbtion ( Bacillus subtilise) absorb onto surface and metals separated by washing bacteria w acidic solution different metals washed off at specific PHs.
Deep sea sediments found to have relatively high conc. rare earth metals.
No viable method exploitation of these but they may be developed as demand for rare earth metals increases
Exploitation of low-grade deposits
Polymer absorbtion
Metal ions dissolved in seawater absorb onto surface of some polymers (synthetic/natural) and can be collected later.
Methods being developed to extract uranium and may provide low energy method of producing fuel for nuclear power industry
Exploiting previously inaccessible deposits
Poly metallic nodules (manganese nodules) metal rich nodules found on many seabeds
Most 5-10 cm diameter found 4000-5000m deep - Formed by chemical ppt Of metals around small solid objects i.e. shell.
30% manganese w smaller amounts iron, nickel, Cu, Colbalt, + titanium
Large-scale exploitation expensive and require international agreement on ownership of resources
Env impacts inc
Recovering nodules disturb seabed and kill benthic organisms
Separating nodules from seabed sediment would increase turbidity of water with unknown consequences
Redeposition of sediment likely to kill filter feeders also covering and killing benthic organisms
Exploiting previously inaccessible deposits
Recycling
Types waste Compare recycling to extraction Transport Labour costs Separation Identification Energy costs Public cooperation Waste losses
- Preconsumer wastes eg offcuttings
- Postconsumer waste- discarded consumer products
Most domestic product waste can be recycled if separated - most effective when undertaken by public as prevent reduction in quality by mixing wastes eg paper and food.
Transport - og mineral - bulk transport heavier - recycled material opposite
Labour costs - processing smaller quantity material increase labour costs but labourers less skill needed so costs lower.
Separation - alloys not easily separated
Identification - labour intensive and slow to identify components of materials where composition important for reuse.
Energy costs - recycling save money for extraction but exceeded if transport small quantities
Energy costs - recycling save energy for extraction but again may b exceeded if lost transport small amounts
Public cooperation- need separation
Waste losses - not all material recyclable - litter
But where recycled material abundant eg aluminium - benefits outweigh costs
Cradle to cradle design
If lifetime of minerals and use can be extended for need to exploit reserves will be reduced
Cradle to cradle design involves the design of products so materials used able to be reused at end of their useful lives.
This includes easy separation of components and identification of materials
Links to the circular economy
