Description: technologyComment of iron ore beneficiation (IN): Milling and mechanical sorting. Average iron yield is 65% . The process so developed basically involves crushing, classification, processing of lumps, fines and slimes separately to produce concentrate suitable as lump and sinter fines and for pellet making. The quality is essentially defined as Fe contents, Level of SiO2 and Al2O3 contamination. The process aims at maximizing Fe recovery by subjecting the rejects/tailings generated from coarser size processing to fine size reduction and subsequent processing to recover iron values. technologyComment of iron ore beneficiation (RoW): Milling and mechanical sorting. Average iron yield is 84%. technologyComment of iron ore mine operation and beneficiation (CA-QC): Milling and mechanical sorting. Average iron yield is 75%. Specific data were collected on one of the two production site in Quebec. According to the documentation available, the technologies of the 2 mines seems similar. Uncertainity has been adjusted accordingly. technologyComment of niobium mine operation and beneficiation, from pyrochlore ore (BR, RoW): Open-pit mining is applied and hydraulic excavators are used to extract the ore with different grades, which is transported to stockpiles awaiting homogenization through earth-moving equipment in order to attain the same concentration. Conveyor belts (3.5 km) are utilized to transport the homogenized ore to the concentration unit. Initially, the ore passes through a jaw crusher and moves to the ball mills, where the pyrochlore grains (1 mm average diameter) are reduced to diameters less than 0.104 mm. In the ball mills, recycled water is added in order to i) granulate the concentrate and ii) remove the gas from the sintering unit. The granulated ore undergoes i) magnetic separation, where magnetite is removed and is sold as a coproduct and ii) desliming in order to remove fractions smaller than 5μm by utilizing cyclones. Then the ore enters the flotation process - last stage of the beneficiation process – where the pyrochlore particles come into contact with flotation chemicals (hydrochloric & fluorosilic acid, triethylamene and lime), thereby removing the solid fractions and producing pyrochlore concentrate and barite as a coproduct which is also sold. The produced concentrate contains 55% Nb2O5 and 11% water and moves to the sintering unit, via tubes or is transported in bags while the separated and unused minerals enter the tailings dam. In the sintering unit, the pyrochlore concentrate undergoes pelletizing, sintering, crushing and classification. These units not only accumulate the material but are also responsible for removing sulfur and water from the concentrate. Then the concentrate enters the dephosphorization unit, where phosphorus and lead are removed from the concentrate. The removal of sulphur and phosphorus have to be executed because of the local pyrochlore ore composition. Then the concentrate undergoes a carbothermic reduction by using charcoal and petroleum coke, producing a refined concentrate, 63% Nb2O5 and tailings with high lead content that are disposed in the tailings dam again. technologyComment of rare earth element mine operation and beneficiation, bastnaesite and monazite ore (CN-NM): Firstly, open pit, mining (drilling and blasting) is performed in order to obtain the iron ore and a minor quantity of rare earth ores (5−6 % rare earth oxide equivalent). Then, a two-step beneficiation process is applied to produce the REO concentrate. In the first step, ball milling and magnetic separation is used for the isolation of the iron ore. In the second step, the resulting REO tailing (containing monazite and bastnasite), is processed to get a 50% REO equivalent concentrate via flotation. technologyComment of rare earth oxides production, from rare earth oxide concentrate, 70% REO (CN-SC): This dataset refers to the separation (hydrochloric acid leaching) and refining (metallothermic reduction) process used in order to produce high-purity rare earth oxides (REO) from REO concentrate, 70% beneficiated. ''The concentrate is calcined at temperatures up to 600ºC to oxidize carbonaceous material. Then HCl leaching, alkaline treatment, and second HCl leaching is performed to produce a relatively pure rare earth chloride (95% REO). Hydrochloric acid leaching in Sichuan is capable of separating and recovering the majority of cerium oxide (CeO) in a short process. For this dataset, the entire quantity of Ce (50% cerium dioxide [CeO2]/REO) is assumed to be produced here as CeO2 with a grade of 98% REO. Foreground carbon dioxide CO2 emissions were calculated from chemical reactions of calcining beneficiated ores. Then metallothermic reduction produces the purest rare earth metals (99.99%) and is most common for heavy rare earths. The metals volatilize, are collected, and then condensed at temperatures of 300 to 400°C (Chinese Ministryof Environmental Protection 2009).'' Source: Lee, J. C. K., & Wen, Z. (2017). Rare Earths from Mines to Metals: Comparing Environmental Impacts from China's Main Production Pathways. Journal of Industrial Ecology, 21(5), 1277-1290. doi:10.1111/jiec.12491 technologyComment of scandium oxide production, from rare earth tailings (CN-NM): See general comment. technologyComment of vanadium-titanomagnetite mine operation and beneficiation (CN): Natural rutile resources are scarce in China. For that reason, the production of titanium stems from high-grade titanium slag, the production of which includes 2 processes: i) ore mining & dressing process and ii) titanium slag smelting process. During the ore mining and dressing process, ilmenite concentrate (47.82% TiO2) is produced through high-intensity magnetic separation of the middling ore, which is previously produced as a byproduct during the magnetic separation sub-process of the vanadium titano-magnetite ore. During the titanium slag smelting process, the produced ilmenite concentrate from the ore mining & dressing process is mixed with petroleum coke as the reducing agent and pitch as the bonding agent. Afterwards it enters the electric arc furnace, where it is smelted, separating iron from the ilmenite concentrate and obtaining high-grade titanium slag.
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Text {
text_type: Report,
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Comment: This is a market activity. Each market represents the consumption mix of a product in a given geography, connecting suppliers with consumers of the same product in the same geographical area. Markets group the producers and also the imports of the product (if relevant) within the same geographical area. They also account for transport to the consumer and for the losses during that process, when relevant. This is the market for 'iron ore concentrate', in the Global geography. This activity represents the global supply of iron ore concentrate (65% Fe, dry basis) to comsuming activities in iron and steelmaking. Transport distances are based on the ecoinvent "Default Transport Assumptions" model, accessible on the ecoinvent website. This market is supplied by the following activities with the given share: niobium mine operation and beneficiation, from pyrochlore ore, BR: 0.000917487531048099 rare earth element mine operation and beneficiation, bastnaesite and monazite ore, CN-NM: 0.0053783839453516 scandium oxide production, from rare earth tailings, CN-NM: 0.000498720250908245 vanadium-titanomagnetite mine operation and beneficiation, CN: 0.0075812778161116 iron ore beneficiation, IN: 0.0184797128319643 iron ore mine operation and beneficiation, CA-QC: 0.0575994859282682 niobium mine operation and beneficiation, from pyrochlore ore, RoW: 0.000121381571398847 iron ore beneficiation, RoW: 0.909423121018547 rare earth oxides production, from rare earth oxide concentrate, 70% REO, CN-SC: 4.29106402225506e-07 generalComment of iron ore beneficiation (IN): This dataset represents iron ore beneficiation to 65%. The following excerpts have been taken from the report Indian Iron Ore Scenario : Low Grade Iron Ore Beneficiation by MECON "Draft National Steel Policy 2012 of India envisages the ambitious goal of the nation to reach a production capacity of 300 Mt/yr of crude quality steel by 2025 - 26. So the corresponding demand of iron ore containing 62 - 64 % Fe would be around 490 Mt (excluding export requirement). To cope up with increasing global and domestic market demand and to achieve the goals of National Steel Policy, Indian steel industry is in need of large quantity of iron ore. Due to increased demand and continuous depletion of high grade iron ore, it has become necessary to develop technology to effectively beneficiate low grade iron ore. Grade % Fe (SiO2+Al2O3)% High-grade > 65% Fe 2% to 4% Medium-grade 62 - 65% Fe 6% to 8% Low-grade < 62% Fe 10% to 15% In the last 15 years a diverse range of new enhanced gravity separators such as Kelsey centrifugal Jigs, Falcon Concentrator, Knelson Concentrator, Multi Gravity Separator (MGS), Altair Jig, Rotating spirals and Water only cyclone have been developed for beneficiation of ultra fines / slimes (below 0.15 mm). These enhanced gravity separators have been proved better for the recovery of iron values from slimes. These operate on the simple principle of the conventional gravity separators but enhanced gravitational force is imparted to increase the inertia of fine particles by using centrifugal force. The forces acting on a particle settling under the influence of centrifugal force are gravity, drag, central buoyancy and frictional forces with gravity and centrifugal forces being predominant. A schematic flow sheet indicating different stages in the beneficiation process alongwith suitable equipment is shown in the attached image." Report by MECON - www.meconlimited.co.in/writereaddata/MIST_2016/sesn/tech_1/5.pdf None imageUrlTagReplace7dcbaff4-585f-4c1f-93a3-242388701dad None generalComment of iron ore beneficiation (RoW): This ore has different grain sizes. It can be lump ore that can be used directly in the blast furnace or it can be ore of smaller grain size that is used for sinter and pellet production. Water emissions are estimated according to the maximal levels for financial support of mining activities by the world bank. [This dataset was already contained in the ecoinvent database version 2. It was not individually updated during the transfer to ecoinvent version 3. Life Cycle Impact Assessment results may still have changed, as they are affected by changes in the supply chain, i.e. in other datasets. This dataset was generated following the ecoinvent quality guidelines for version 2. It may have been subject to central changes described in the ecoinvent version 3 change report (http://www.ecoinvent.org/database/ecoinvent-version-3/reports-of-changes/), and the results of the central updates were reviewed extensively. The changes added e.g. consistent water flows and other information throughout the database. The documentation of this dataset can be found in the ecoinvent reports of version 2, which are still available via the ecoinvent website. The change report linked above covers all central changes that were made during the conversion process.] generalComment of iron ore mine operation and beneficiation (CA-QC): This dataset represents the production of 1 kg of iron concentrate containing 66.15% of Fe (dry basis) in Quebec in 2011. The concentrate is produced at 4% humidity. Specific data were collected for one compagny which represents nearly 65% of the Québec's production for the year 2011. The iron ore is extracted in two open pit mine; the main pit, where 92% of the ore is extracted, is located on the same site as the concentrator and the extra pit, used only when needed, is located 60 km from the concentrator. The ore is then transported by train. 65% of the 2011 production have been used in the production of iron pellet in Québec, the rest has been sold to other part of Canada, United States, Europe and China. None generalComment of niobium mine operation and beneficiation, from pyrochlore ore (RoW): This dataset has been copied from an original dataset covering the geography of BR. The data is assumed to be also representative of the global situation, since Brazil produces more than 87% of niobium concentrates and pyrochlore is the leading mineral for the production of niobium (Source: https://prd-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/atoms/files/myb1-2017-niobi.pdf). This dataset refers to the production of 1 kg of (refined) pyrochlore concentrate (63% beneficiated), as a result of the mining and beneficiation activities in Araxa, Brazil. generalComment of niobium mine operation and beneficiation, from pyrochlore ore (BR): This dataset refers to the production of 1 kg of (refined) pyrochlore concentrate (63% beneficiated), as a result of the mining and beneficiation activities in Araxa, Brazil. generalComment of rare earth element mine operation and beneficiation, bastnaesite and monazite ore (CN-NM): This dataset refers to the mining (open pit mining) and beneficiation (two step beneficiation process including ball milling and magnetic separation) activities, in order to produce 1 kg of rare earth oxide (REO) concentrate, 50% beneficiated, from the extracted monazite and bastnaesite minerals in the Bayan obo mines. China is the top producer of Rare Earth metals in the world, being responsible for approximately 81.4% of the global production (Source: https://prd-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/atoms/files/myb1-2017-raree.pdf). This dataset is based on the Critical Materials Life Cycle Assessment Tool (CMLCAT), an excel based software that complements the publication of Arshi et al (2018) (reference 1), which contains the LCI data for each subprocess mentioned in the publication. The amounts of the byproducts iron concentrate and rare earth tailings were taken from the Wang et al (2020) publication (reference 2). The produced rare earth concentrate will then undergo acid roasting, water leaching & chlorine conversion, solvent extraction and calcination in order to produce high purity individual lanthanum oxide, cerium oxide, neodymium oxide and a mixed samarium-europium gadolinium concentrate (outside of this system boundaries). Reference 1: Arshi, P. S., Vahidi, E., & Zhao, F. (2018). Behind the Scenes of Clean Energy: The Environmental Footprint of Rare Earth Products. ACS Sustainable Chemistry & Engineering, 6(3), 3311-3320. doi:10.1021/acssuschemeng.7b03484. Reference 2: Wang, L., Jiao, G., Lu, H., & Wang, Q. (2019). Life cycle assessment of integrated exploitation technology for tailings in Bayan Obo Mine, China. Applied Ecology and Environmental Research, 17, 4343-4359. doi:10.15666/aeer/1702_43434359 generalComment of rare earth oxides production, from rare earth oxide concentrate, 70% REO (CN-SC): For the separation and refining of rare earth oxides in the Sichuan region of China. This dataset is based on the following publication: Arshi, P. S., Vahidi, E., & Zhao, F. (2018). Behind the Scenes of Clean Energy: The Environmental Footprint of Rare Earth Products. ACS Sustainable Chemistry & Engineering, 6(3), 3311-3320. doi:10.1021/acssuschemeng.7b03484 and the critical materials life cycle assessment tool (CMLCAT) of Arshi et al. (2018), provided by F. Zhao from Purdue University. Specific modifications were made in order to make the dataset more transparent. Background: Metals are produced as part of a complex, highly interconnected and interdependent system, with many desirable but scarce/critical metals recovered as by-products during the production of one or more ‘host’ metal(s). Currently, mining and processing of rare earth elements is predominantly carried out in China, where they are extracted mainly via open pit mining of bastnäsite and/or monazite deposits or the leaching of ion-adsorption clays. Modelling approach: This dataset was created using the critical materials life cycle assessment tool (CMLCAT) of Arshi et al. (2018). generalComment of scandium oxide production, from rare earth tailings (CN-NM): This dataset refers to the beneficiation and smelting activities in order to produce 1 kg of Scandium oxide (Sc2O3), with purity greater than 99.9% from rare earth tailings in the Bayan obo mines in the Baotou region of China. The rare earth tailings are produced as a byproduct from the mining and beneficiation activities of the REE-Nb-Fe ore at the same location. China is top producer of Scandium, being responsible for 90% of the global scandium production (Source: https://www.scandiummining.com/site/assets/files/5740/scandium-white-paperemc-website-june-2014-.pdf). Today, scandium is produced either as a co-product of other primary metal projects or is extracted out of old tailings from depleted mining projects where the specific process happened to concentrate scandium levels. (Source: https://www.scandiummining.com/scandium/scandium-faq/). This dataset is based on the publication of Wang et al (2020) (reference 1). The boundaries of the system have been expanded in order to include the processing of fluorite coarse ore that is produced as a byproduct during the scandium oxide production, due to the fact that there was no available proxy for the ore in Ecoinvent, The processing produces fluorite concentrate which was represented as fluorspar which exists in Ecoinvent. The data for the processing of fluorite was taken from Wang et al 2019 (reference 2 – consult the respective exchange comment). Due to lack of data regarding the data acquisition time, the dataset generator has relied on the previous work of the same author that dealt with the production of scandium concentrate from the Bayan Obo tailings (see reference 2 –data coverage until the beneficiation stage). Wang et al 2019 mentions that the data were acquired during 2014-2018. Therefore, because the data is recent, the dataset is assumed valid from 2018 until 2022 (5 years). Furthermore, the electricity is taken from the grid, meaning that all upstream inputs and outputs are already taken into account. Finally, the steam is generated from coal burning. For further information, consult the sampling procedure and the individual exchange comments. Reference 1: Wang, L., Wang, P., Chen, W.-Q., Wang, Q.-Q., & Lu, H.-S. (2020). Environmental Impacts of Scandium Oxide Production from Rare Earths Tailings of Bayan Obo Mine. Journal of Cleaner Produc-tion, 122464. doi:https://doi.org/10.1016/j.jclepro.2020.122464 Reference 2: Wang, L., Jiao, G., Lu, H., & Wang, Q. (2019). Life cycle assessment of integrated exploitation technology for tailings in Bayan Obo Mine, China. Applied Ecology and Environmental Research, 17, 4343-4359. doi:10.15666/aeer/1702_43434359 This dataset includes the beneficiation stage and the smelting stage, including 5 major processes and 22 sub-processes. The first stage consists of 3 separation steps (i.e first separation, secondary separation, and final separation), during which scandium is separated and concentrated to produce Scandium (Sc) concentrate for the smelting stage. During the smelting stage – consisting of metallurgy and purification processes – Sc oxide is extracted from the concentrate to produce high-purity (>99.9%) Sc2O3. Beneficiation stage: The beneficiation stage is comprised of the first, secondary and final separation. During the first separation, the remaining iron and rare earth elements (REEs) are separated from the REE tailings, through the sub-processes of iron separation, REE separation). Afterwards, bulk flotation is applied to the remaining tailings, dividing them into mixed foam and mixed grit, in order to separate easily flotating and iron-silicate minerals and reduce the difficulty of the next recycling. The mixed foam separates fluorite and the mixed grit, containing approximately 0.02-0.03% scandium. Then the mix grit goes to the secondary separation (including the sub-processes of sulfur flotation (I), iron separation (II), gravity concentration, sulfur flotation (II), and Fe separation (III) in order to separate the sulfur and the remaining iron (byproducts) and thus further enrich the scandium. Sulfur flotation (I) and further iron separation is necessary in order to decrease the difficulty of Niobium (Nb) separation. Then gravity separation is performed in order to isolate the gangue materials from the grit, and simplify the Nb separation. At this point, the original tailings have been reduced to concentrates and Scandium-enriched remaining tailings (with 0.02-0.03% Sc content). The concentrates undergo again sulfur flotation (I) and iron separation (II) to further separate iron and sulfur and -as a result- further enrich the scandium in the remaining tailings, reaching a content of 0.03-0.04% Sc. After the first and secondary separation, iron, sulfur and REEs have been completely separated and the remaining valuable elements to be extracted from the tailings contain Nb and Sc. Nb separation is performed first, because of the Sc existence in silicate materials. Pyroxene and amphibole (silicate minerals) are recycled by a strong magnetic separation process and divided from the Nb tailings and gravity concentration tailings, producing high-quality Sc concentrates (approximately 0.05% Sc content). The concentrates are then fed to the smelting stage for the production of high purity Sc2O3. Smelting stage: The smelting stage consists of the metallurgy and the purification process. The metallurgy step incorporates the processes of concentration, ore grinding, and pressure filtration (physical extraction), normal acid leaching, pressure acid leaching, and extraction. The Sc concentrates produced from the beneficiation step are further concentrated and the residues are grinded (particle size reach 200-325 mesh) to the output rate. Pressure filtration separates the solid and liquid containing Scandium. After that, (normal and pressurized) acid leaching is applied to extract the Scandium-containing substance (20-30% Sc content) from the acid leaching solution, which goes to the purification process, which includes 6 sub-processes: Ti cleaning, Fe cleaning, back extraction, purification, oxalic acid precipitation, and calcination. At first, residual titanium and iron are removed first to avoid impacting the further purification sub-processes. The ideal cleaning rate can be attained by applying high number of washing steps (i.e. 20). However too much washing can potentially lead to significant scandium losses. Then, the addition of sodium hydroxide within the Sc-containing solution produces a soda cake, containing Nb and Sc. Subsequently, niobium and scandium oxide are produced from filter cake and filtrate respectively, which are created through purification of the soda cake, after the addition of hydrochloric acid solution. Excessive addition of oxalic acid to the filtrate produces scandium oxalate precipitates, which are later burned at a temperature of 800°C in order to produce high-purity (>99.9%) scandium oxide (Sc2O3). generalComment of vanadium-titanomagnetite mine operation and beneficiation (CN): This dataset refers to the production of 1 kg of high-grade titanium slag (94% TiO2) from vanadium-titanomagnetite ore in the city of Panzhihua & Xichang region in China. It includes the activities of ore mining & dressing (during which titanium concentrate is produced) and titanium slag smelting (during which high-grade titanium slag with 94% TiO2 content is produced). The dataset is based on the Gao et al (2018) publication. For this dataset, the data for mining were taken from Table 1 and figure 2 of the abovementioned source. The waste rock reported in table 1 is not taken into account, because it is assumed that is left on-site and used as backfill material, therefore remaining within system boundaries. Data for infrastructure, land occupation & transformation as well as emissions during mining were approximated with data from the Ecoinvent dataset ''ilmenite - magnetite mine operation, GLO'' available in version 3.7.1 of the Ecoinvent database. The data for mining in table 2, column ''ore mining and dressing'' from the Gao et al (2018) publication were not considered due to mass allocation in that specific column. Nevertheless, for the titanium slag smelting process the data were taken from the respective column in table 2 of the Gao et al (2018) publication. Finally, the grade of slag is not reported in the Gao et al (2018) and was instead taken from the Liao et al (2012) publication, since it refers to production of high-grade slag (as intermediate product) in Panzhihua city. The transport distance was also taken from the Liao et al (2012) publication. Reference 1: Gao, F., Nie, Z., Yang, D., Sun, B., Liu, Y., Gong, X., & Wang, Z. (2018). Environmental impacts analysis of titanium sponge production using Kroll process in China. Journal of Cleaner Production, 174, 771-779. doi:https://doi.org/10.1016/j.jclepro.2017.09.240. Reference 2: Liao, W., Heijungs, R., & Huppes, G. (2012). Thermodynamic resource indicators in LCA: a case study on the titania produced in Panzhihua city, southwest China. The International Journal of Life Cycle Assessment, 17(8), 951-961. doi:10.1007/s11367-012-0429-4.
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