Title Analiza ciklusa eksploatacije kvarcnoga pijeska u Hrvatskoj : doktorski rad Title (english) Life Cycle Assessment of Silica Sand Exploitation and Processing in Croatia : doctoral thesis Author Anamarija Grbeš Mentor Gordan Bedeković (mentor)Committee member Trpimir Kujundžić (predsjednik povjerenstva)Committee member Gordan Bedeković (član povjerenstva)Committee member Frankica Kapor (član povjerenstva)Committee member Josip Mesec (član povjerenstva)Committee member Ivan Sobota (član povjerenstva)Granter University of Zagreb Defense date and country 2014-05-22, Croatia Scientific / art field, TECHNICAL SCIENCES Universal decimal classificationUDC ) 622 - Mining Abstract Kvarcni pijesak je sirovina sa širokim spektrom primjena od kojih su najpoznatije primjene u
industriji stakla i građevinarstvu. Republika Hrvatska raspolaže s potvrđenim rezervama od
oko 40 milijuna tona i dugom tradicijom eksploatacije koja se posljednjih godina odvija
smanjenim kapacitetom. Prosječna godišnja proizvodnja rovnog kvarcnog pijeska u Hrvatskoj
iznosi oko 150 tisuća tona. Eksploatacija kvarcnog pijeska sastoji se od dobivanja rovnog
kvarcnog pijeska strojnim iskopom na površinskim kopovima te oplemenjivanja u
oplemenjivačkom postrojenju u svrhu daljnjeg plasmana na tržište (industriju).
U ovom radu analizira se životni ciklus kvarcnog pijeska od dobivanja na površinskom kopu
do ulaza u tvornicu stakla. U tu svrhu dizajnirano je sedam varijanti (alternativa) eksploatacije
kvarcnog pijeska s razlikama u oplemenjivačom procesu, dok je osma varijanta generička,
kreirana isključivo korištenjem Ecoinvent baze podataka. Za potrebe projektiranja varijanti
generirana je baza podataka s kapacitetima rudarskih strojeva i opreme korištenjem kataloga i
specifikacija proizvodača koji su postavljeni na Internetu. Dobiveni rezultati i normativi
varijanti uspoređeni su s podacima na terenu kako bi se provjerila njihova reprezentativnost.
Procjena utjecaja i grafički prikaz podataka provedeni su uz pomoć programa Sima Pro. Za
procjenu utjecaja odabrana je metoda ReCiPe u kojoj se utjecaji na okoliš izražavaju pomoću
osamnaest indikatora srednje točke koji se zatim preko mehanizama okoliša prevode na razinu
krajnje točke utjecaja, a to su štetni utjecaji na ljudsko zdravlje, ekosustave i troškove
proizvodnje resursa (zbog npr. smanjenja njihove dostupnosti).
Rezultati indikatora krajnje točke za kategorije utjecaja na ljudsko zdravlje, ekosustave i
povećanje ukupne godišnje cijene resursa su pokazali kako u oplemenjivanju kvarcnog
pijeska najjednostavniji postupci kao što su pranje i klasiranje imaju najmanje utjecaje. Uz
uvjet da su ispuštanja toksičnih tvari iz procesa oplemenjivanja u sastavnice okoliša
onemogućena ili svedena na minimum, presudan utjecaj na okoliš medu alternativama ima
potrošnja vode. Promatrano od dobivanja rovnog pijeska na površinskom kopu, preko
transporta i oplemenjivanja kvarcnog pijeska, korištenje fosilnih goriva pokazalo se kao
najvažniji čimbenik utjecaja na okoliš cradle-to-gate dijela životnog ciklusa kvarcnog pijeska.
Korištenje električne energije nije se pokazalo značajnim u pogledu izravnih utjecaja, ali
svakako doprinosi utjecajima neposredno, preko proizvodnje električne energije. Transport mokrog pijeska vlažnosti 6% (mas.) i sušenje otpadnom toplinom u tvornici stakla pokazala se kao bolja opcija nego sušenje pijeska do vlažnosti manje od 1% u pogonu za oplemenjivanje i transport do tvornice stakla.
Abstract (english) Introduction: Silica sand or quartz sand is mineral resource with wide varieties of
applications; glass industry and construction are the most common example. Republic of
Croatia has confirmed reserves of 40 million tons and long tradition of exploitation and
processing. Average production of raw silica sand in Croatia is 150 thousand tons.
This paper defines the procedure for life cycle assessment of silica sand exploitation
and processing and gives a model of quartz sand life cycle. Environmental profiles of
different processing options are calculated, and included in cradle to gate life cycle study of
silica sand for glassmaking industry. Based on environmental profiles of different options,
key segments of production process are identified and ranked. A guideline for choice of
technology that includes direct and indirect environmental impacts at design level is given.
Materials and methods. In this research eight alternatives of silica sand production process
are designed. For the purpose of design, equipment and machinery database is generated.
Designed inputs and outputs in production processes are checked for consistency with
industry data. Life cycle assessment is performed using Sima Pro software. Life cycle impact
assessment is performed using ReCiPe midpoint and endpoint method.
Analyzed alternatives are:
• Alternative 1: Surface exploitation (excavation) using bulldozers; transportation from
excavation site to processing plant (3 km) using dumpers; washing and sizing; drying;
electrostatic separation of feldspar, magnetic separation of magnetic minerals; road
transport of dried silica sand (water content less than 1% mass) using lorry (truck) on
transporting distance 100 km.
• Alternative 2-1: Surface exploitation (excavation) using bulldozers; transportation
from excavation site to processing plant (3 km) using dumpers; washing and sizing;
road transport of wet silica sand (water content 6% mass) using lorry (truck) on
transporting distance 100 km; drying in glass plant using waste heat.
• Alternative 2-2: Surface exploitation (excavation) using bulldozers; transportation
from excavation site to processing plant (3 km) using dumpers; washing and sizing;
drying; road transport of dried silica sand (water content less than 1% mass) using
lorry (truck) on transporting distance 100 km.
• Alternative 3-1. Surface exploitation (excavation) using bulldozers; transportation
from excavation site to processing plant (3 km) using dumpers; washing and sizing;
flotation of mica, heavy minerals and feldspar; road transport of wet silica sand
(water content 6% mass) using lorry (truck) on transporting distance 100 km; drying
in glass plant using waste heat.
• Alternative 3-2. Surface exploitation (excavation) using bulldozers; transportation
from excavation site to processing plant (3 km) using dumpers; washing and sizing;
flotation of mica, heavy minerals and feldspar; drying; road transport of dried silica
sand (water content less than 1% mass) using lorry (truck) on transporting distance
100 km. Alternative 4-1. Surface exploitation (excavation) using bulldozers;
transportation from excavation site to processing plant (3 km) using dumpers;
washing and sizing; gravitation concentration of quartz; road transport of wet silica
sand (water content 6% mass) using lorry (truck) on transporting distance 100 km;
drying in glass plant using waste heat.
• Alternative 4-2. Surface exploitation (excavation) using bulldozers; transportation
from excavation site to processing plant (3 km) using dumpers; washing and sizing;
gravitation concentration of quartz; drying; road transport of dried silica sand (water
content less than 1% mass) using lorry (truck) on transporting distance 100 km.
• Alternative 5. Simulation of surface exploitation and mineral processing outside the
Croatia (data for sand production in Switzerland) and silica sand import by railroad
transport on distance 700 km using EcoInvent database
Among the analyzed alternatives the following alternatives have shown the smallest impact:
“5” (simulation based on Ecoinvent data); “2-1” (silica sand production from high quality raw
sand utilizing simple processing techniques such as sizing and washing ); “2-2” (silica sand
production from high quality raw sand utilizing simple processing techniques such as sizing
and washing plus drying in the rotary drier); “4-1” (silica sand production utilizing processing
techniques such as sizing, washing and gravity concentration); “3-1” (silica sand production
utilizing processing techniques such as sizing, washing and froth flotation). Intermediate
impact have shown the alternatives “1” (silica sand production utilizing processing techniques
such as sizing, washing, drying with grain surface conditioning using hydrofluoric acid, and
electrostatic separation) and “4-2” (silica sand production utilizing processing techniques such
as sizing, washing, gravity concentration and drying). The highest impact has shown the
alternative “3-2” (silica sand production utilizing processing techniques such as sizing,
washing, flotation and drying). Process contribution analysis has shown the major
contribution following from using fossil fuels and water.
Conclusion and recommendations. In silica sand processing the simplest mineral processing
methods such as sand washing and classifying have the smallest impacts. When emissions of
chemicals to environment are prevented or minimal, deciding factor between the processing
alternatives has the water consumption. Second factor affecting significantly the
environmental performance in silica sand processing is the fossil fuel use. In cradle-to-gate
production process (including silica sand exploitation, processing and transportation) the
fossil fuel use (and production) has the major impact on environment. Damage from
electricity use (and production) is considerably lower. Transportation of naturally dried wet
sand (w=6%) and drying using waste heat in glass factory is better option than drying in
processing plant and then transporting it into the glass factory.
Recommendations for lowering the environmental impact of silica sand at different
production stages:
• In surface mining: lowering the diesel consumption using mining machinery with
good fuel efficiency per ton of produced sand and utilization of mining machinery
with continuous working regime instead of cyclic (e.g. rotary or bucket excavator
instead of bulldozer);
• In sand washing and wet classifying: the use of efficient water collection,
regeneration and recirculation systems
• In flotation: the use of flotation reagents that can be easily separated from water
(based on their phase) and/or recirculated back into the process.
• In electrostatic separation: the use of highly efficient drying system.
• In drying: lowering the fossil fuel consumption; utilizing as much as possible the
gravitational dewatering and natural evaporation; drying using waste heat or other heat
sources that cause less damage than fossil fuels.
Keywords
kvarcni pijesak
analiza životnog ciklusa
utjecaj na okoliš
eksploatacija
oplemenjivanje
Keywords (english)
silica sand
life cycle assessment
environmental impact
exploitation
mineral processing
Language croatian URN:NBN urn:nbn:hr:169:101942 Promotion 2014-09-28 Study programme Title: Applied Geosciences, Mining and Petroleum Engineering Catalog URL http://katalog.nsk.hr/F/?func=direct&CON_LNG=ZAG&local_base=ZAG01_WEB&doc_number=000588505 Type of resource Text Extent 146 str. ; 30 cm File origin Born digital Access conditions Open access Terms of use Created on 2017-11-30 12:48:10
