chromite ore concentrate production, UPR, ecoinvent 3.6, Undefined
Location: GLO - Global
This dataset describes the production of The module describes the production of 1 kg of chromite ore concentrate in 1994 for a world-wide production average. It is designed for the use of chromite as intermediary product in the produc-tion of ferrochromium, dichromate and refractories. Process data is taken mainly from d a material flow analysis for the consumption of chromium compounds in Germany.
This dataset describes the production of 1 kg of chromite ore concentrate in 1994 for a worldwide production average. It is designed for the use of chromite as intermediary product in the production of ferrochromium, dichromate and refractories. Process data is taken mainly from d a material flow analysis for the consumption of chromium compounds in Germany.
Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.
Mining is done 21% open pit and 79% underground, followed by a benefication of the ore trough classification. Overburden and tailings are disposed near the mining site.
MINING:
Chromite ores are usually mined underground. An estimated share of 71% underground mining has been reported for activities in the mine production in 1994. This represents 78% of the total production. Of a surveyed part of 52% of the total world production, 69% of the chromite originated from stratiform deposits.
Emissions and waste: The major emissions are due to mineral born pollutants in the effluents. Open cut mining generates large quantities of dust, which contains elevated contents of metals. Rain percolates through overburden and leads to metal emissions to groundwater. Overburden is deposed close to the mine.
BENEFICIATION:
After mining, the ore is first crushed in several stages with jaw and / or cone crushers, and then subsequently ground with rod and or ball mills and finally screened for classification. In a second step the classified material is subjected to gravity concentration to separate the metal-bearing particles from the unwanted minerals. For this drum separators and de-watering screens for lumps are used and cone separators and a high-gradient magnetic separator for fine material. No flotation is done. The separated gangue is disposed in tailings ponds, the concentrated ore is fed to the metallurgy, which is on-site. Chromite yields vary in a range from 65% to 85%. There's no treatment of wastewater.
Emissions and waste: Ore handling and processing produce large amounts of dust, containing PM10 and several metals from the ore itself. Tailings are deposed as piles and in ponds. Since the tailings are not sulphidic, no acid rock drainage (ARD) occurs. In the tailings material the most significant contents are Cr and Ni, which occur as insoluble compounds and are considered not to cause any negative effects.
References:
Adelhardt W. and Antrekowitsch H. (1998) Stoffmengenflüsse und Energie-bedarf bei der Gewinnung ausgewählter mineralischer Rohstoffe; Teilstudie Chrom. In: Geologisches Jahrbuch, Vol. Sonderhefte SH 3. Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover. ISBN 3-510-95831-4.
IPPC (2002) Integrated Pollution Prevention and Control (IPPC); Draft Refer-ence Document on Best Available Techniques for Management of Tailings and Waste-Rock in Mining Activities. European Commission. Retrieved at 01.03.2003 from http://www.jrc.es/pub/english.cgi/0/733169
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