Unit 4: Earth’s Resources Environmental Science. NONRENEWABLE RESOURCES A nonrenewable resource is...
-
Upload
phoebe-george -
Category
Documents
-
view
218 -
download
0
Transcript of Unit 4: Earth’s Resources Environmental Science. NONRENEWABLE RESOURCES A nonrenewable resource is...
NONRENEWABLE RESOURCES
A nonrenewable resource is a natural resource that cannot be re-made or re-grown at a scale comparable to its consumption.
COAL, PETROLEUM, AND GAS
Coal, petroleum, and natural gas are considered nonrenewable
because they can not be replenished in a short period of
time. These are called fossil fuels.
NUCLEAR ENERGYNuclear fission
uses uranium to create energy.
Nuclear energy is a nonrenewable
resource because once the uranium
is used, it is gone!
RENEWABLE RESOURCES
Renewable resources are natural resources that can be replenished in a short period of time.
● Solar ● Geothermal● Wind ● Biomass● Water
Metal ResourcesBiggest Users of Metals• United States• Japan• EuropeBiggest Producers• South America• South Africa• Former Soviet Union .
Metal ResourcesMetal Uses
Iron Heavy machinery, steel production
Aluminum Packaging foods & beverages, transportation, electronics
Manganese High-strength, high-resistant steel alloys
Copper Building construction, electric/electroni industry
Chromium High strength steel alloy
Nickel Chemical industry, steel alloys
Lead Leaded gasoline, car batteries, paint, ammunition
Silver Photography, electronics, jewelry
Gold Medical, aerospace, electronic use, money, jewelry
Platinum Automobile catalytic converters, electronics, medical uses, jewelry-
Non-Metal Resources• Sand & gravel
– Uses: brick & concrete construction, paving, road filler, sandblasting, glass (high silica content sand)
• Limestone– Uses: concrete, road rock, building stone, pulverized to
neutralize acidic soil or water.
• Evaporites- halite, gypsum, potash– Uses: halite- rock salt for roads, refined into table salt– Gypsum- makes plaster wallboard– Potash- for fertilizer (potassium chloride, potassium
sulfates)
• Sulfur deposits– Uses: sulfuric acid in batteries & some medicinal products
Steps in Obtaining Mineral Commodities1. Prospecting- finding places where ores
occur2. Mine exploration & development- learn
whether ore can be extracted economically
3. Mining- extract ore from ground4. Beneficiation- separate ore minerals
from other mined rock5. Smelting & refining- extract pure mineral
from ore mineral (get the good stuff out of waste rock)
6. Transportation- carry mineral to market7. Marketing & sales- find buyers & sell the
mineral
Types of Mining
• Surface- scoop ore off surface of the earth or dig big holes and scoop– Cheap– Safe for miners– Large amount of
environmental destruction
• Subsurface- use shafts to reach deeply buried ores– Expensive– Hazardous for miners– Less environmental
damage
Types of Surface Mining1. Open Pit Mining
a. Overlaying material is removed using large equipment
b. Creates pits that are hundreds of meters wide and hundreds of meters deep.
Types of Surface Mining
2. Strip mining– Like open pit but not
as deep of a pit– Same environmental
damage
Large bucket wheel extractor being moved through Germany. Moves 10 meters per minute. Takes 5 people
to operate. Used in strip mining
Types of Surface Mining
• Dredging– Sand is removed
from bottom of ocean
– Can be done to restore beaches (after hurricane)
– Destroys fragile benthic ecosystems
Types of Subsurface mining• Room and Pillar mining
– Remove rock/ore from rooms and leave pillars for support.
Types of Subsurface mining• Longwall mining
– One long strip (wall) of coal is mined in a single strip (0.5 – 1.0 m at a time)
Health Problems• mine collapse• fire (methane, coal dust,
etc.). • asphyxiation (methane,
carbon monoxide)• pneumoconiosis (from
inhaling coal dust) • asbestosis (from inhaling
asbestos fibers) • silicosis (from inhaling
silicate dust) • heavy metal poisoning (e.g.
mercury) • radiation exposure (in
uranium mining)
Environmental Damage• Gaping holes in ground (old open pit mines)• Accidental draining of rivers and lakes • Disruption of ground water flow patterns • Piles of gangue- mine tailings (mining waste)• Loss of topsoil in strip-mined regions (350 to 2,700 km2 in US
alone)• Spoil banks are where holes were filled in with waste- cheap &
easy- susceptible to erosion, chemical weathering, causes high sediment runoff in watersheds. Steep slopes are slow to re-vegetate (succession happens slowly- no topsoil)
• Contamination of soil or water from heavy metals (e.g. arsenic, mercury) in mine tailings.
• Contamination from sulfuric acid (H2SO4) produced through weathering of iron sulfide (FeS2, pyrite) in tailings.
– 4FeS2 + 14H2O = 4Fe(OH)3 + 8H2SO4
• Water leaking into mine shafts, washes dissolved metals & toxic material into water sources.
– (550,000 abandoned mines in U.S.- 12,000 mi of rivers & streams contaminated with mine drainage- cost to clean up $32-$72 billion)
Acid Mine Acid Mine DrainageDrainage
The impact of mine drainage on a lake after
receiving effluent from an abandoned
tailings impoundment
for over 50 years
Relatively fresh tailings in an Relatively fresh tailings in an impoundment. impoundment.
The same tailings impoundment The same tailings impoundment after 7 years of sulfide after 7 years of sulfide
oxidation. The white spots in oxidation. The white spots in Figures A and B are gulls. Figures A and B are gulls.
http://www.earth.uwaterloo.ca/services/whaton/s06_amd.html
Shoreline of a pond receiving AMD showing massive accumulation of iron hydroxides on the pond bottom
Surface Mining Control & Reclamation Act (SMCRA)
• 1977• Requires better restoration
of strip-mined lands• Restoration is difficult &
expensive• Takes long time for soil to
regain fertility– Topsoil gets buried– Compacted, poor drainage– Root growth restricted
• Minimum cost- $1000 per acre
• Complete restoration (if possible)- $5,000 per acre
History of Supplemental Energyin United States
Wood through mid-1800s-Renewable
-Maximum sustained yield limits supply
Wood through mid-1800s-Renewable
-Maximum sustained yield limits supply
Coal replaced wood by 1900Coal replaced wood by 1900Oil, natural gas exploited (since mid-1900s)
#1-oil, #2-natural gas, #3-coal- all non-renewable
Oil, natural gas exploited (since mid-1900s)
#1-oil, #2-natural gas, #3-coal- all non-renewable
Use growing dramaticallyUse growing dramatically
Year
210020251950187518000
20
40
60
80
100
Con
trib
utio
n to
tot
al e
nerg
yco
nsum
ptio
n (p
erce
nt)
Wood
Coal
Oil
Nuclear
HydrogenSolar
Natural gas
How long will supplies last?
U.S. (5% pop) uses 25% of energyU.S. (5% pop) uses 25% of energyDepends on:
- rate of use- discovery of new supplies
Depends on:- rate of use
- discovery of new suppliesResource supply lifetime
- oil - 30-60 years- natural gas - 50-200 years
- coal - 650-900 years
Resource supply lifetime- oil - 30-60 years
- natural gas - 50-200 years- coal - 650-900 years
Oil Shale and Tar Sands
Oil shale3X conventional
Oil shale3X conventional
Kerogen25 gallons/ton
Energy in=energy out
Kerogen25 gallons/ton
Energy in=energy out Tar sands Tar sands
Bitumen3X return on energy inputs
Bitumen3X return on energy inputs
Natural Gas
50-90% methane 50-90% methane
Propane, butaneremoved, liquified
Propane, butaneremoved, liquified
Cleanest burning,lowest costs
Cleanest burning,lowest costs
Problems: leaks,explosions
Problems: leaks,explosions
Coal
Bituminous most abundant (52%), buthigh in sulfur
Bituminous most abundant (52%), buthigh in sulfur
Anthracite most ideal (high energy, lowsulfur), but least abundant (2%)
Anthracite most ideal (high energy, lowsulfur), but least abundant (2%)
Lignite (8%) low energy, low pollutionpotential
Lignite (8%) low energy, low pollutionpotential
Burning Coal More Cleanly
Fluidized-Bed Combustion
Fluidized-Bed Combustion
-calcium-calciumsulfate (limestone)sulfate (limestone) used w/ Coal.used w/ Coal.
Coal Gasification - methane
Raw coal
Pulverizer
Air oroxygen
Steam
Pulverized coalSlag removal
Recycle unreactedcarbon (char)
Raw gasesClean
methane gas
Recoversulfur
Methane(natural gas)
2CCoal
+ O2 2CO
CO + 3H2 CH4 + H2O
Remove dust,tar, water, sulfur
Coal Liquefaction - liquid fuels
Both gasification and liquefaction lose30-40% of energy contained in coal
Both gasification and liquefaction lose30-40% of energy contained in coal
Nuclear Energy
Tremendous potential, plagued bysafety and cost problems
Tremendous potential, plagued bysafety and cost problems
3 ways to produce nuclear power1) conventional nuclear fission reactor2) breeder nuclear fission reactor3) nuclear fusion reactor
3 ways to produce nuclear power1) conventional nuclear fission reactor2) breeder nuclear fission reactor3) nuclear fusion reactor
Nuclear Energy
Use radioactive isotopesUse radioactive isotopesIsotopes - different forms of same
element- atoms have differing masses- e.g. U-238, U-235
Isotopes - different forms of sameelement- atoms have differing masses- e.g. U-238, U-235
Radioactive - unstable atoms emitradiation (rays and particles)
Radioactive - unstable atoms emitradiation (rays and particles)
Nuclear Energy
Conventional fission reactors
Conventional fission reactors
Uranium-235(U-238 common)
Uranium-235(U-238 common)
Nucleus split by moving
neutron
Nucleus split by moving
neutron
- Core, heat exchanger, generator
Nuclear Energy
Breeder fission reactorsBreeder fission reactorsUses plutonium-239 as fuel
U-238 + neutron = Pu-239
Uses plutonium-239 as fuelU-238 + neutron = Pu-239
Pu-239 fissioned, but more producedfrom U-238- produces more Pu-239 than it uses
Pu-239 fissioned, but more producedfrom U-238- produces more Pu-239 than it uses
Nuclear Energy
Nuclear fusion reactorsNuclear fusion reactorsCombine atoms of hydrogen isotopes
- deuterium, tritium
Combine atoms of hydrogen isotopes- deuterium, tritium
Requires high temperature- 100 million °C- experimental- uncontrolled fusion = hydrogen bomb
Requires high temperature- 100 million °C- experimental- uncontrolled fusion = hydrogen bomb
Problems with Nuclear Power
Safety Safety Disposal of radioactive wastesDisposal of radioactive wastesUse of fuel for weaponsUse of fuel for weaponsReduced growth in demand for
electricity
Reduced growth in demand for electricity
High construction, operating costsHigh construction, operating costs
Funding Funding
Safety Concerns
Radiation concerns Radiation concerns Susceptible tissues: reproductive
organs, bone marrow, digestive tract, spleen, lymph glands, fetuses
Susceptible tissues: reproductive organs, bone marrow, digestive tract, spleen, lymph glands, fetuses
Rem - unit of radiation exposure- 10 rems: low level, few effects- 100 rems: sterility, no short-term deaths- 1000 rems: death in days
Rem - unit of radiation exposure- 10 rems: low level, few effects- 100 rems: sterility, no short-term deaths- 1000 rems: death in days
Big Fears
Core meltdown- Chernobyl ‘86
Core meltdown- Chernobyl ‘86
Containment shell ruptureContainment shell rupture
Both have potential for releasing huge amounts of radiation
Both have potential for releasing huge amounts of radiation
Disposal of Radioactive Wastes
No long-term storage facility- protected for 10,000 years- radiation declines to low levels
No long-term storage facility- protected for 10,000 years- radiation declines to low levels
Most wastes stored on-siteMost wastes stored on-site
Site under development- Yucca Mountain in Nevada
Site under development- Yucca Mountain in Nevada