environmental geochemistry iii. - mendeluxcepl/inobio/eopory/environmental... · environmental...

Environmental Geochemistry III.

Aleš Bajer

Tento projekt je spolufinancován Evropským sociálním fondem a Státním rozpočtem ČR InoBio – CZ.1.07/2.2.00/28.0018

Environmental Geochemistry

Resources

Mineral Resources and Mining

Fossil and Uranium Fuels

Alternative Energy Resources


Mineral Resources and Mining

- 2 categories: metallic and nonmetalic rocks and minerals

- place with enrichment of one or more mineral = MINERAL DEPOSIT

- deposit of metal-bearing minerals that can be mined at a profit = ORE

- Ore forms by magmatic,hydrothermal, sedimentary, weathering and

metamorphic processes

-Mineral resources are mined in two ways:

a) OPEN PIT MINE (surface)

b) TUNNEL MINE (underground)


HOW ORE FORMS?

- By magmatic processes: crystal settling

- solid minerals are denser than

liquid magma.

- crystals sink to the bottom of

a magma chamber

- in this way heavy metals

(platinum, chromium…) forms


HOW ORE FORMS?

- by magmatic processes: pegmatites

- water-rich granitic magma causes solidification of large crystals

- rock with extremely coarse-grained minerals is called pegmatite

- extreme size of particular crystals of feldspar, quartz and mica

(10 x 5 m)

- certain rare elements also concentrate in pegmatites (beryl, lepidolite,

tourmaline,…)


HOW ORE FORMS? Hydrothermal ore deposits are results of precipitating from

hot water solution. Fluorite, Galena, Barite


HOW ORE FORMS? Submarine hydrothermal ore deposits

Precipitate from circulating seawater

near the mid-oceanic ridge.


HOW ORE FORMS?

- by sedimentary processes: sedimentary sorting

-Placer deposits from where water currents slow down and deposit

heavy minerals (gold)


MINERAL RESERVES

- may increase in two ways:

a) discovery new mineral deposits

b) by increasing a price or improving a technology of extraction

noneconomic mineral deposits change into profitable ones

Changes in the reserves

of some types of ore


MINERAL RESERVES

- 4 nations – the United States, Germany, Japan and the former Soviet

Union consume about 75% of used metals, but their population is only

15% of world population. (China 10% - 16%)


MINERAL RESERVES

- predictions of future supplies of selected materials use in industry


ENERGY RESOURCES

Energy is the basic condition for our current western life style.

- things like hot water, air condition, car, fresh kiwi in the middle

of winter is matter of course for this life style – all depend on

plentiful cheap energy

What are energy resources?

- Fossil Fuels (coal, petroleum and natural gass)

- Uranium Fuels

- Alternative resources

Fossil and Uranium Fuels influence on environment negatively.

Recently we put the accent on alternative resource searching and

saving energy.


ENERGY RESOURCES

Source of energy production Use of energy in particular sectors


COAL

- formed from decayed remains of plants in swaps – peat

by increasing temperature and pressure

- there are various types of coal (lignite, brown coal, black coal,

antracite)

Coal mining: a) underground coal-mining

– causes subsidence and colaps surface

b) opencast coal-mining

- causes extensive devastation of land

- changes on landscape surface and water

drainage

Use: electricity production (power station) = 60%

steel factory =30%

steam factory =10%

In the Czech Rep. the coal is used for individual house heating.


COAL

negative results:

- pollution (acid rain, carbon dioxide emission, thermal pollution in

water

- electromagnetic radiation is escaping at transmission


COAL

Formation of coal


COAL

Areas in USA where attractive coal deposits are found


PETROLEUM (OIL)

- formed from organic matter in shallow coastal waters during

rising temperature and pressure

- convert the organic matter to liquid petroleum

- Petroleum is dispersed in the rock – oil traps

Driling and pumping causes oil spills and land degradation

Transport (pipeline, tanker): oil spills

Refining process causes:

- air and water pollution

Use: gasoline burning – causes air pollution (CO2, NOX, Pb)


PETROLEUM (OIL)

Formation of an oil reservoir


PETROLEUM (OIL)

Products of rafinery treat

Oil pollution

Environmental Geochemistry PETROLEUM

Four basic types of oil traps

Environmental Geochemistry PETROLEUM

Global oil reserves and oil consumption

Consumption by country: USA (20 mil), China (7,5 mil), Japan (5 mil),

Russia (2,8 mil), India (2,7 mil), Germany (2,5), CZ (200.000)

EU (15 mil)


NATURAL GAS

- similar using like petroleum, but causes less pollution

- less world supplies and higher price

- the leading producer is Russia (problematic supplying)

- CZ 10 years ago – almost every individual house heating was

using natural gas x now incresing price of natural gas

= return to coal (increasing of local pollution)


URANIUM AND ATOMIC ENERGY

spontaneous emission of

radiation from an element –

radioactivity

- nuclear power plants

use nuclear fission

- fuel is isotope of uranium

U-235 (not spontaneous)

- natural uranium contains

only 1% U-235

- increasing of U-235 is

necessary for using fuel

- used in the form of small

pellets



Radioactive Wastes

- after mining the material is radioactive

- during enrichment radioactive wastes are produced

- fission process produces radioactive waste

(it is more radioactive than original U-235)

- no satisfactory sollution has been found yet

(no permanent storage exists)

- at present there are short-term (till 50 years) and middle-term

(150-200 years) storing

- nowdays pellets are testing to be reprocessed to recover U-235

- lifetime of nuclear power plant is about 50 years – there is

question what to do with it?



The nuclear fuel

cycle

Temporary storage

Permanent storga



Radioactive accident

-generally people are scared about accident at nuclear power

plants

- there were two big accident in past

1979 – USA, Pensylvania, Three Mile Island nuclear power plant

1986 – former Soviet Union, Chernobyl (Ukraine)

- These accidents influenced on large area

Chernobyl – half of Europe

- The accidents was caused by human failures

- Control – warning systems were off

In my opinion atomic energy is alternative for fossil fuels under

the concrete conditions.


ENERGY CONSERVATION (SAVING)

42,5% energy waste could be avoided with conservation


ENERGY CONSERVATION

- using technologies with higher efficiency


ALTERNATIVE ENERGY RESOURCES

-The first opportunity is consistent energy discipline

in household, industry and transportation

- SOLAR ENERGY

- passive solar heating



SOLAR ENERGY

-active solar heating (solar collectors)

trap the solar energy and use it to heat water

there are a few problems:

- it is more expensive

- it works only during the sunlight period

- it wants too much space for to be productivity

for example: generating 100 mil. Watts =

energy for 50.000 people it needs 3 km2 of solar panels

In spite of all of this solar energy has the greatest potential

of all alternative energy resources



SOLAR ENERGY

Boom of solar energy in CZ causes higher price of el. Energy

Weakness: solar energy needs to be doubled



Hydroelectric Energy

- use the energy of water droping down-ward throught the dam

- produces almost of 20% of the world´s electricity

- hydroenergetic plants do not pollute the water and do not

disturb hydrologic cycle

- dams and hydropower systems radically alter stream ecosystem

- today huge hydroelectric dam project are building in China,

Brasil, India, Nepal and Canada

- all of these project influence on environment

- the biggest producer is China

- in the Czech Rep. the hydroelectric sites are limited.

- potential is much lower than in Austria or Switzerland



Geothermal Energy

- energy extracted from the earth´s heat

- there are two forms:

- dry heat (transformation from hot rock into medium)

- wet heat (hot spring water is using)

- typical for place with high geothermal activity (vulcanic activity,

earthquake, hot springs)

- in the Czech Rep. geothermal energy is using only locally

- unlike Slovak Rep. and Hungary where it is more common



Geothermal Energy

Schematic view of dry geothermal

energy plant

Steam escapes from hot water

heated by deep hot rock



Wind Energy

-the specific form of solar energy – sun´s heat creates wind

- it can be use in places with strong and standy wind

- windmills has been used to pump water since Middle Age

- today „wind farms“ are generating electricity

- they are using especilly in California and Hawaii

- in the Czech Rep. the using of this energy is starting to be

discussed. Places with good wind conditions were selected.

- wind energy is discussed in the view of noice and view pollution.



Biomass Energy

-the main resource (wood) of heating in past

- today it is used for local burning stoves

- produces so much smoke and pollution especially in winter

- today there are special plant products for production of bioenergy

- it is prefered as alternative energy resources in EU

- large agriculture sites are using for these plants

Energy from the seas

- tidal energy: are not always economical, there are some projects

but not realy using

- wave energy: there are a few wave generators in Northern

Ireland and England



Energy for future?

- nuclear fussion: the energy of stars such as the sun

produces when H combine to form He

- huge amount of energy 1 g = 9400 l of gasoline

- the process is known in the view of theory

- but not prepared for realization in the view of technology now!

Conclusion

However there are still quite enough of fossill fuel reserves

it is important to increase using of alternative energy resources.

Energy saving (decreasing of energy use) unlike wasting can increase

the amount of available energy in the quickest and least expensive way.

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