Energy Resources. Uranium (U) – used for nuclear power Has a Minimum Concentration Factor > 1000...
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Transcript of Energy Resources. Uranium (U) – used for nuclear power Has a Minimum Concentration Factor > 1000...
Energy Resources
• Uranium (U) – used for nuclear power• Has a Minimum Concentration Factor > 1000• Source Rock – Igneous• U is leached (dissolved) into groundwater• Deposit Types
– Sandstones that have been enriched with U minerals (groundwater enrichment)
– U-bearing minerals in rock fractures– Placer Deposits
Nuclear Power - Uranium
Hydroelectric and Tidal Power
• Movement of water drives turbines
• Dams – gravity key force
• Tidal – tidal force, need a tidal range of > 8 m (nearly impractical)
Geothermal Energy
• Temperature increases with depth ~ 3oC/ 100 m
• Geothermal energy concentrated where magma is near the surface
• Circulation of groundwater allows water to heat up
• Hot groundwater drives turbines
Mineral Resources
Daily Questions
• Within your groups, identify one task you all have completed today. Collectively think about the task and brainstorm. Produce a list of all of the mineral resources that were used in that task.
Some Important Minerals and there Uses
• Galena [PbS] – source of lead – car batteries
• Magnetite, Hematite [FexOy] – iron ore
• Bauxite [Al2O3*2H2O] – aluminum ore
• Chalcopyrite [CuFeS2] – copper ore
• Quartz [SiO2] – glass and electronic components
• Gypsum [CaSO4*2H2O] – sheetrock, plater of paris
• Sphalerite [ZnS] – zinc ore
• Calcite [CaCO3] – portland cement, soil conditioner, antacids
• Garnet [Al2(SiO4)3+other metals] – abrasives
• Olivine [(Fe,Mg)2SiO4] – silicon chips for computers
• Sulfur [S] – insecticides, rubber tires, paints, papermaking, etc.• Halite [NaCl] – Table salt• Graphite [C] – lubricant, pencil lead• Feldspars [K,Ca,Na,Al, silicates] – porcelain, source of K• Any other element that is not a major component of a mineral• Gold [Au], Silver [Ag], Platinum [Pt], Titanium [ Ti], Tin [Sn], etc.
Reserves vs. Resources
• Reserves– Natural resources that
have been discovereddiscovered && can be exploited exploited profitablyprofitably with existing technology
– Oil – 700 billion barrels
• Resources– Deposits that we know
or believe to exist, but that are not exploitable today because of technological, economical, or political reasons
– Oil – 2 trillion barrels
Nonrecoverable resources(present in the earth but not obtainable
with present technology)
Recoverable resources(not likely to be economic
in foreseeable future)
Unconceived Resources
Hypothetical, speculative, or inferred resources
Total Resources
Degree of geologic assurance
Deg
ree
of e
cono
mic
fea
sibi
lity
Limit of crustal abundance
Technological Threshold
Potential Economical Threshold
High
High
Low
Low
Known resources (located but not measured)
Proven Resources
Discovered Undiscovered
• Elements comprise > 0.1% (by weight) of the crust
• Form as principal component in minerals within common rocks – i.e. iron (Fe) Fe2O3
• Form very large deposits
• Form rock deposits
Geochemically Abundant Elements (GAE)
Geochemically Scarce Elements (GSE)
• Elements that comprise < 0.1% (by weight) of the crust
• Do not form as principal component in minerals within common rocks, usually occur as a substitute in rock forming minerals
• Form small deposits• Ore minerals include sulfides, native elements,
etc.
Will run out
Abundant
Mineral Deposits
• Elements need to be concentrated• Minimum Grade - minimum amount of element
necessary to economically mine element• Minimum Concentration Factor (MCF) –
Minimum Grade divided by the Crustal Abundance – GAE have MCF < 100
– GSE have MCF > 100
Comparison of Concentrations of Elements in the Earth’s Crust with Concentrations needed to operate
a Commercial Mine
Element Natural Concentration in Crust (% by Weight)
Concentration Required to Operate a commercial mine (% by Weight)
Enrichment Factor
Aluminum 8 24-32 3-4
Iron 5.8 40 6-7
Copper 0.0058 0.46-0.58 80-100
Nickel 0.0072 1.08 150
Zinc 0.0082 2.46 300
Uranium 0.00016 0.19 1200
Lead 0.00010 0.2 2000
Gold 0.0000002 0.0008 4000
Mercury 0.000002 0.2 100,000
Process that concentrate elements
• Igneous Processes– Hydrothermal– Magmatic
• Sedimentary Processes– Mechanical– Chemical
• Metamorphism Processes• Groundwater Processes
• Precipitation of metallic ions from hot, ion-rich fluid
• Fluid could be– Magmatic– Groundwater– Oceanic water
• Magmas heat up the water• Water flows into fractures,
faults, joints, etc. where it cools and precipitates (deposits) the metals
Hydrothermal Processes
Magmatic Processes• Gravity Settling
– Dense, early-crystallizing minerals sink to the bottom of the magma chamber
• Filter Pressing– Tectonic force compress a
magma chamber and force the still-liquid portion into fractures, creating large crystals
• These processes have produced large bodies of iron, chromium, titanium, and nickel
Sedimentary Processes• Clastic
– Weathering of rock also weathers out elements of interest
– Generally, the elements are heavy and are deposited when a streams competence is low.
– Placer deposits, i.e. gold
Placer Gold
Sedimentary Processes• Chemical
Precipitates– Water with high
concentrations of elements is evaporated
– Evaporation of water leaves the elements
– Ex. Salts, Iron, etc.
Metamorphism
• Alteration of rock concentrates the elements
• The heat and pressure force out the GSE (“impurities”)
• Chemical weathering removes soluble material.
• Ore material (elements of interest) are left behind in a concentrated residue.
Weathering
Groundwater• Secondary enrichment• Groundwater dissolves and carries elements in
solution• Chemical conditions change and the elements are
precipitated (deposited) out.• Ex. Lead
Groundwater• Secondary enrichment• Groundwater dissolves and carries
insignificant elements in solution• Insoluble elements of interest remain.• Ex. Aluminum
Ore Mineral
• Ability to separate and readily process the metal (element) from the ore material.
• Need to look at– The energy to process the material– The cost to process the material– The value of the metal
• Basically, is it profitable to mine the metal?
Mineralogical Barrier
• Increase in energy and cost associated with the production of GSE
Energy and Costper mass of
metal
$
Grade of metal (element) in rock HighLow
GAEGSE
Mineralogical Barrier
FixedCosts
Metals trapped in minerals (silicates)
Metals the have been concentrated
Ways to overcome the mineralogical barrier
• Improve technology
• Recycle
• Come up with cheap energy to break silicate bonds
Daily Assignment
Place the following on the Venn Diagram
1.Gold
2.Oil
3.Coal
4.Iron
5.Copper
6.Gravel
15
2, 3, 6
4
Plate Tectonics and Resources