technologyComment of manganese production (RER): The metal is won by electrolysis (25%) and electrothermic processes (75%). ELECTROLYSIS OF AQUEOUS MANGANESE SALTS The production of manganese metal by the electrolysis of aqueous manganese salts requires at first a milling of the manganese ore. Milling increases the active surface and ensures sufficient reactivity in both the reduction and the subsequent leaching steps. After milling the manganese ore is fed to a rotary kiln where the reduction and calcination takes place. This process is carried out at about 850 - 1000 ºC in a reducing atmosphere. As a reducing agent, several carbon sources can be used e.g. anthracite, coal, charcoal and hydrocarbon oil or natural gas. The cal-cined ore needs to be cooled below 100 ºC to avoid a further re-oxidation. The subsequent leaching process is carried out with recycled electrolyte, mainly sulphuric acid. After leaching and filtration the iron content is removed from the solution by oxidative precipitation and the nickel and cobalt are removed by sulphide precipitation. The purified electrolyte is then treated with SO2 in order to ensure plating of γ-Mn during electrolysis. Electrolysis is carried out in diaphragm cells. The cathode is normally made of stainless steel or titanium. For the anode lead-calcium or lead-silver alloy can be used. After an appropriate reaction time the cathodes are removed from the electrolysis bath. The manganese that is deposited on the cathode starter-sheet is stripped off mechanically and then washed and dried. The metal is crushed to produce metal flakes or powder or granulated, depending on the end use. ELECTROTHERMAL DECOMPOSITION OF MANGANESE ORES The electrothermal process is the second important process to produce manganese metal in an industrial scale. The electrothermal process takes place as a multistage process. In the first stage manganese ore is smelted with only a small amount of reductant in order to reduce mostly the iron oxide. This produces a low-grade ferro-manganese and a slag that is rich in Mn-oxide. The slag is then smelted in the second stage with silicon to produce silicomanganese. The molten silicomanganese can be treated with liquid slag from the fist stage to obtain relatively pure manganese metal. For the last step a ladle or shaking ladle can be used. The manganese metal produced by the electrothermal process contains up to 98% of Mn. Overall emissions and waste: Emissions to air consist of dust and fume emissions from smelting, hard metal and carbide production; Other emissions to air are ammonia (NH3), acid fume (HCl), hydrogen fluoride (HF), VOC and heavy metals. Effluents are composed of overflow water from wet scrubbing systems, wastewater from slag and metal granulation, and blow down from cooling water cycles. Waste includes dust, fume, sludge and slag. References: Wellbeloved D. B., Craven P. M. and Waudby J. W. (1997) Manganese and Manganese Alloys. In: Ullmann's encyclopedia of industrial chemistry (ed. Anonymous). 5th edition on CD-ROM Edition. Wiley & Sons, London. IPPC (2001) Integrated Pollution Prevention and Control (IPPC); Reference Document on Best Available Techniques in the Non Ferrous Metals Industries. European Commission. Retrieved from http://www.jrc.es/pub/english.cgi/ 0/733169 technologyComment of manganese production (RoW): The metal is won by electrolysis (assumption: 25%) and electrothermic processes (assumption: 75%). No detailed information available, mainly based on rough estimates. technologyComment of treatment of non-Fe-Co-metals, from used Li-ion battery, hydrometallurgical processing (GLO): The technique SX-EW is used mainly for oxide ores and supergene sulphide ores (i.e. ores not containing iron). It is assumed to be used for the treatment of the non-Fe-Co-metals fraction. The process includes a leaching stage followed by cementation or electro-winning. A general description of the process steps is given below. In the dump leaching step, copper is recovered from large quantities (millions of tonnes) of strip oxide ores with a very low grade. Dilute sulphuric acid is trickled through the material. Once the process starts it continues naturally if water and air are circulated through the heap. The time required is typically measured in years. Sulphur dioxide is emitted during such operations. Soluble copper is then recovered from drainage tunnels and ponds. Copper recovery rates vary from 30% to 70%. Cconsiderable amounts of sulphuric acid and leaching agents emit into water and air. No figures are currently available on the dimension of such emissions. After the solvent-solvent extraction, considerable amounts of leaching residues remain, which consist of undissolved minerals and the remainders of leaching chemicals. In the solution cleaning step occur precipitation of impurities and filtration or selective enrichment of copper by solvent extraction or ion exchange. The solvent extraction process comprises two steps: selective extraction of copper from an aqueous leach solution into an organic phase (extraction circuit) and the re-extraction or stripping of the copper into dilute sulphuric acid to give a solution suitable for electro winning (stripping circuit). In the separation step occurs precipitation of copper metal or copper compounds such as Cu2O, CuS, CuCl, CuI, CuCN, or CuSO4 • 5 H2O (crystallisation) Waste: Like in the pyrometallurgical step, considerable quantities of solid residuals are generated, which are mostly recycled within the process or sent to other specialists to recover any precious metals. Final residues generally comprise hydroxide filter cakes (iron hydroxide, 60% water, cat I industrial waste).
technologyComment of aluminium alloy production, AlLi (CA-QC, RoW): No comment present technologyComment of aluminium alloy production, Metallic Matrix Composite (CA-QC, RoW): No comment present technologyComment of cobalt production (GLO): Cobalt, as a co-product of nickel and copper production, is obtained using a wide range of technologies. The initial life cycle stage covers the mining of the ore through underground or open cast methods. The ore is further processed in beneficiation to produce a concentrate and/or raffinate solution. Metal selection and further concentration is initiated in primary extraction, which may involve calcining, smelting, high pressure leaching, and other processes. The final product is obtained through further refining, which may involve processes such as re-leaching, selective solvent / solution extraction, selective precipitation, electrowinning, and other treatments. Transport is reported separately and consists of only the internal movements of materials / intermediates, and not the movement of final product. Due to its intrinsic value, cobalt has a high recycling rate. However, much of this recycling takes place downstream through the recycling of alloy scrap into new alloy, or goes into the cobalt chemical sector as an intermediate requiring additional refinement. Secondary production, ie production from the recycling of cobalt-containing wastes, is considered in this study in so far as it occurs as part of the participating companies’ production. This was shown to be of very limited significance (less than 1% of cobalt inputs). The secondary materials used for producing cobalt are modelled as entering the system free of environmental burden. technologyComment of copper production, cathode, solvent extraction and electrowinning process (GLO): Oxide ores and supergene sulphide ores (i.e. ores not containing iron) can be recovered most easily by hydro-metallurgical techniques, such as SX-EW. The general steps of mining and refining are identical to those of copper mine operation and primary copper production, respectively. The difference lies in that the beneficiation and smelting stages are by-passed and substituted with a leaching stage followed by cementation or electro-winning. technologyComment of electrorefining of copper, anode (GLO): Based on typical current technology. technologyComment of gold mine operation and refining (SE): OPEN PIT MINING: The ore is mined in four steps: drilling, blasting, loading and hauling. In the case of a surface mine, a pattern of holes is drilled in the pit and filled with explosives. The explosives are detonated in order to break up the ground so large shovels or front-end loaders can load it into haul trucks. ORE AND WASTE HAULAGE: The haul trucks transport the ore to various areas for processing. The grade and type of ore determine the processing method used. Higher-grade ores are taken to a mill. Lower grade ores are taken to leach pads. Some ores may be stockpiled for later processing. HEAP LEACHING: The ore is crushed or placed directly on lined leach pads where a dilute cyanide solution is applied to the surface of the heap. The solution percolates down through the ore, where it leaches the gold and flows to a central collection location. The solution is recovered in this closed system. The pregnant leach solution is fed to electrowinning cells and undergoes the same steps as described below from Electro-winning. ORE PROCESSING: Milling: The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder. Oxidization and leaching: Some types of ore require further processing before gold is recovered. In this case, the slurry is pressure-oxidized in an autoclave before going to the leaching tanks or a dry powder is fed through a roaster in which it is oxidized using heat before being sent to the leaching tanks as a slurry. The slurry is thickened and runs through a series of leaching tanks. The gold in the slurry adheres to carbon in the tanks. Stripping: The carbon is then moved into a stripping vessel where the gold is removed from the carbon by pumping a hot caustic solution through the carbon. The carbon is later recycled. Electro-winning: The gold-bearing solution is pumped through electro-winning cells or through a zinc precipitation circuit where the gold is recovered from the solution. Smelting: The gold is then melted in a furnace at about 1’064°C and poured into moulds, creating doré bars. Doré bars are unrefined gold bullion bars containing between 60% and 95% gold. References: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp technologyComment of platinum group metal mine operation, ore with high palladium content (RU): imageUrlTagReplace6250302f-4c86-4605-a56f-03197a7811f2 technologyComment of platinum group metal, extraction and refinery operations (ZA): The ores from the different ore bodies are processed in concentrators where a PGM concentrate is produced with a tailing by product. The PGM base metal concentrate product from the different concentrators processing the different ores are blended during the smelting phase to balance the sulphur content in the final matte product. Smelter operators also carry out toll smelting from third part concentrators. The smelter product is send to the Base metal refinery where the PGMs are separated from the Base Metals. Precious metal refinery is carried out on PGM concentrate from the Base metal refinery to split the PGMs into individual metal products. Water analyses measurements for Anglo Platinum obtained from literature (Slatter et.al, 2009). Mudd, G., 2010. Platinum group metals: a unique case study in the sustainability of mineral resources, in: The 4th International Platinum Conference, Platinum in Transition “Boom or Bust.” Water share between MC and EC from Mudd (2010). Mudd, G., 2010. Platinum group metals: a unique case study in the sustainability of mineral resources, in: The 4th International Platinum Conference, Platinum in Transition “Boom or Bust.” technologyComment of primary zinc production from concentrate (RoW): The technological representativeness of this dataset is considered to be high as smelting methods for zinc are consistent in all regions. Refined zinc produced pyro-metallurgically represents less than 5% of global zinc production and less than 2% of this dataset. Electrometallurgical Smelting The main unit processes for electrometallurgical zinc smelting are roasting, leaching, purification, electrolysis, and melting. In both electrometallurgical and pyro-metallurgical zinc production routes, the first step is to remove the sulfur from the concentrate. Roasting or sintering achieves this. The concentrate is heated in a furnace with operating temperature above 900 °C (exothermic, autogenous process) to convert the zinc sulfide to calcine (zinc oxide). Simultaneously, sulfur reacts with oxygen to produce sulfur dioxide, which is subsequently converted to sulfuric acid in acid plants, usually located with zinc-smelting facilities. During the leaching process, the calcine is dissolved in dilute sulfuric acid solution (re-circulated back from the electrolysis cells) to produce aqueous zinc sulfate solution. The iron impurities dissolve as well and are precipitated out as jarosite or goethite in the presence of calcine and possibly ammonia. Jarosite and goethite are usually disposed of in tailing ponds. Adding zinc dust to the zinc sulfate solution facilitates purification. The purification of leachate leads to precipitation of cadmium, copper, and cobalt as metals. In electrolysis, the purified solution is electrolyzed between lead alloy anodes and aluminum cathodes. The high-purity zinc deposited on aluminum cathodes is stripped off, dried, melted, and cast into SHG zinc ingots (99.99 % zinc). Pyro-metallurgical Smelting The pyro-metallurgical smelting process is based on the reduction of zinc and lead oxides into metal with carbon in an imperial smelting furnace. The sinter, along with pre-heated coke, is charged from the top of the furnace and injected from below with pre-heated air. This ensures that temperature in the center of the furnace remains in the range of 1000-1500 °C. The coke is converted to carbon monoxide, and zinc and lead oxides are reduced to metallic zinc and lead. The liquid lead bullion is collected at the bottom of the furnace along with other metal impurities (copper, silver, and gold). Zinc in vapor form is collected from the top of the furnace along with other gases. Zinc vapor is then condensed into liquid zinc. The lead and cadmium impurities in zinc bullion are removed through a distillation process. The imperial smelting process is an energy-intensive process and produces zinc of lower purity than the electrometallurgical process. technologyComment of treatment of copper cake (GLO): 'The ore is pre-treated, reduced and refined according to the country specific mix of process alternatives: reverberatory furnace 23.7%; flash smelting furnaces 60.7%; other 6.2%.; SX-EW 9.4%. An overall abatement for sulphur dioxide of 45.4% was estimated.' as cited in original dataset. technologyComment of treatment of copper scrap by electrolytic refining (RoW): In three different stages different types of copper scrap and 10% of the feed of blister copper are refined to copper cathodes. Waste water is led to a communal treatment plant. technologyComment of treatment of copper scrap by electrolytic refining (RER): Secondary copper consists of various types of scrap. Prompt scrap is directly reused in foundries and is not further processed. Old scrap has to be treated in a secondary copper smelter, where a variety of metal values are recuperated. Depending on the chemical composition, the raw materials of a secondary copper smelter are processed in different types of furnaces, including: - blast furnaces (up to 30% of Cu in the average charge), - converters (about 75% Cu), and - anode furnaces (about 95% Cu). A scheme of the process considered is given in Fig 1. The blast furnace metal (“black copper”) is treated in a converter; then, the converter metal is refined in an anode furnace. In each step additional raw material with corresponding copper content is added. In the blast furnace, a mixture of raw materials, iron scrap, limestone and sand as well as coke is charged at the top. Air that can be enriched with oxygen is blown through the tuyeres. The coke is burnt and the charge materials are smelted under reducing conditions. Black copper and slag are discharged from tapholes. The converters used in primary copper smelting, working on mattes containing iron sulphide, generate surplus heat and additions of scrap copper are often used to control the temperature. The converter provides a convenient and cheap form of scrap treatment, but often with only moderately efficient gas cleaning. Alternatively, hydrometallurgical treatment of scrap, using ammonia leaching, yields to solutions which can be reduced by hydrogen to obtain copper powder. Alternatively, these solutions can be treated by solvent extraction to produce feed to a copper-winning cell. Converter copper is charged together with copper raw materials in anode furnace operation. For smelting the charge, oil or coal dust is used, mainly in reverberatory furnaces. After smelting, air is blown on the bath to oxidise the remaining impurities. Leaded brasses, containing as much as 3% of lead, are widely used in various applications and recycling of their scrap waste is an important activity. Such scrap contains usually much swarf and turnings coated with lubricant and cutting oils. Copper-containing cables and motors contain plastic or rubber insulants, varnishes, and lacquers. In such cases, scrap needs pre-treatment to remove these non-metallic materials. The smaller sizes of scrap can be pre-treated thermally in a rotary kiln provided with an after-burner to consume smoke and oil vapours (so-called Intal process). Emissions and waste: Elevated levels of halogenated organic compounds may arise, such as TCDD. Slags are usually used in construction. Waste water is led to a communal treatment plant. References: EEA, 1999. imageUrlTagReplacef2b602ec-dc47-48e3-88a7-ab8ec727bd33 technologyComment of treatment of metal part of electronics scrap, in copper, anode, by electrolytic refining (SE, RoW): Production of cathode copper by electrolytic refining. technologyComment of treatment of non-Fe-Co-metals, from used Li-ion battery, hydrometallurgical processing (GLO): The technique SX-EW is used mainly for oxide ores and supergene sulphide ores (i.e. ores not containing iron). It is assumed to be used for the treatment of the non-Fe-Co-metals fraction. The process includes a leaching stage followed by cementation or electro-winning. A general description of the process steps is given below. In the dump leaching step, copper is recovered from large quantities (millions of tonnes) of strip oxide ores with a very low grade. Dilute sulphuric acid is trickled through the material. Once the process starts it continues naturally if water and air are circulated through the heap. The time required is typically measured in years. Sulphur dioxide is emitted during such operations. Soluble copper is then recovered from drainage tunnels and ponds. Copper recovery rates vary from 30% to 70%. Cconsiderable amounts of sulphuric acid and leaching agents emit into water and air. No figures are currently available on the dimension of such emissions. After the solvent-solvent extraction, considerable amounts of leaching residues remain, which consist of undissolved minerals and the remainders of leaching chemicals. In the solution cleaning step occur precipitation of impurities and filtration or selective enrichment of copper by solvent extraction or ion exchange. The solvent extraction process comprises two steps: selective extraction of copper from an aqueous leach solution into an organic phase (extraction circuit) and the re-extraction or stripping of the copper into dilute sulphuric acid to give a solution suitable for electro winning (stripping circuit). In the separation step occurs precipitation of copper metal or copper compounds such as Cu2O, CuS, CuCl, CuI, CuCN, or CuSO4 • 5 H2O (crystallisation) Waste: Like in the pyrometallurgical step, considerable quantities of solid residuals are generated, which are mostly recycled within the process or sent to other specialists to recover any precious metals. Final residues generally comprise hydroxide filter cakes (iron hydroxide, 60% water, cat I industrial waste). technologyComment of treatment of non-Fe-Co-metals, from used Li-ion battery, pyrometallurgical processing (GLO): Based on technology that treats anode slime by pressure leaching and top blown rotary converter. technologyComment of treatment of used cable (GLO): Shredder, followed by a modern grinding machine with current separation technology
Das Projekt "Hot gas-cleaning" wird vom Umweltbundesamt gefördert und von DMT-Gesellschaft für Forschung und Prüfung mbH durchgeführt. General Information: Descriptions of the individual parts of the project are given below. Removal of trace elements in hot gas cleaning systems (CSIC). Study of the capture of trace elements by a range of different sorbents - mainly metal mixed oxides, clay materials and alkaline-earth carbonates but also some alumina and siliceous materials - in two laboratory scale reactors (a fixed bed and a fluidised bed) at temperatures between 550 and 750 degree C. Different compositions of the simulated coal gas stream will also be tested. Different sorbents, temperatures and stream gas composition will be studied during each of three periods of six months in each of the three years of the programme. Hot H2S Removal by using waste products as solvents (TGI). Testing of red mud (a residue from aluminium manufacture) and electric arc furnace dust (a residue from steel making) as sorbents for hot dry desulphurisation of coat derived fuel gas. These materials have been chosen as containing potential sorbents including calcium, iron, zinc and manganese oxides. Tests will be carried out in a laboratory-scale pressurised reactor. Use of carbon materials and membranes for hot gas clean up (DMT). Study of the potential use of carbon materials for removing trace metals and sulphur compounds from hot gasification gases (also potentially the separation of light gases such as hydrogen), taking advantage of the stability of carbon at high temperature and in corrosive atmospheres. A bed of carbon (or, where appropriate, another material) alone or in combination with a carbon filtering membrane installed in a laboratory gas circuit will be used: - to study the effect on composition of passing gas from a gasifier through a bed of activated carbon or a carbon molecular sieve at various temperatures, pressures and flow rates. - to repeat the studies as above with a filtering membrane made from carbon added. - to study the combination of sorption/filtration and catalytically active materials (i.e. using catalysts for the CO shift and for hydrogenation). The use of other compounds such as zeolitic membranes or granular beds will also be considered and the advantages of using combined gas clean up systems will be reviewed in the light of the data obtained. Development of improved stable catalysts and trace elements capture for hot gas cleaning in advanced power generation (CRE Group). Studies will be carried out on existing equipment to improve and assess catalysts based on iron oxide on silica and titania with mixed metal oxides to remove ammonia, hydrogen cyanide, hydrogen chloride, arsine, hydrogen sulphide and carbonyl sulphide. Selected catalysts will be tested at pressures up to 20 bar and temperatures in the range 500 - 800 degree C using simulated atmospheres. ... Prime Contractor: Deutsche Montan Technologie, Gesellschaft für Forschung und Prüfung mbH (DMT); Essen; Germany.
Das Projekt "Use of Geothermal Water to heat a Recreational Resort in Weiden (Bavaria)" wird vom Umweltbundesamt gefördert und von Stadt Weiden i. d. OPf. durchgeführt. Objective: To use geothermal water for thermal spa applications and sauna in a recreational resort centre to be built in Weiden. The reservoir at 1300 m depth is made of detrital formations overlying granitic and gneissic basement. Expected flow rate is about 18 m3/h of drinking water at 35 degree of Celsius. Water will be treated and filtered before use in baths to avoid Fe and Mn oxydes. Well drilling will be realized close to the resort site to have the shortest distribution network possible. General Information: The well was drilled to a final depth of 1459,75 m between November 88 and September 89. It was fitted with 7 5/8' casing down to 960 m. Two sections (583-797 m and 851-941 m) were left free from cementation for later tapping measures (perforation). At a depth of 1230 a hydro carbonaceous zone has been struck. Oil tests and loggings were done and the cored interval for the installation of casing had to be enlarged. After completion of the oil tests the oil bearing zone has been sealed by installation of a 159 mm casing down to 1224 m. Mud loss occurred between 1309 and 1319 m and between 1383 and 1389. Pumping tests in the open hole showed a flow rate of 0,05 l/s at 150 m depression. To get a sufficient output higher aquifers (857-933 m and 608 - 753 m) were tapped by perforation. Long time pumping tests were carried out (November, December 1990) out and showed an output of about 7,2 m3/h at about 23 degree of Celsius. Achievements: This project encountered difficulties when the drilling crossed an hydro carbonaceous zone. (0,4 m3 of oil has been produced). This problem led the operator to cement the lowest part of the drilling and to produce water from a shallower reservoir with both low temperature and flow rate. The well is exploited at 6,5 m3/h - 23 degree of Celsius. The discharge temperature is 14 degree of Celsius and the power of 106 kWht. Annual energy savings expected are 65 TOE.
Das Projekt "Bildung von N2O bei der Umsetzung von Ammoniak mit N2O5 an Aerosolen" wird vom Umweltbundesamt gefördert und von Fraunhofer-Institut für Toxikologie und Aerosolforschung durchgeführt. N2O, ein klimawirksames Spurengas, zeigt einen weltweit zunehmenden Trend. Neben direkten Emissionen aus (geduengten) Boeden und dem Meer, sowie aus Verbrennungsprozessen, kann es auch aus der Luftchemie von NOx und Ammoniak gebildet werden. In diesem Vorhaben wird die Bildung von N2O aus der heterogenen Reaktion von N2O5 und NH3 an Aerosoloberflaechen untersucht. Zunaechst wurden die auf den Wandmaterialien: Borsilikatglas, Teflon und Polyethylen gefundenen Blindwerte und der Feuchteeinfluss bestimmt. Dann wurde die N2O-Bildung an suspendiertem Aerosol (NH4NO3, Russ, SiO2, Fe2O3, Al2O3 und TiO2) gemessen. Die gefundene N2O-Bildung ist umweltrelevant und haengt stark ab von der Art des Aerosols, aber auch von der Art der Versuchsdurchfuehrung.
Etwa 5% der Treibhausgasemissionen der Europäischen Union sind auf die Stahlindustrie zurückzuführen. Insbesondere bei der Gewinnung von Rohstahl entstehen erhebliche Mengen an CO2 als Nebenprodukt. Das Fraunhofer IKTS (Institut für Keramische Technologien und Systeme) hat deshalb die Minderung der Emissionen durch elektrolysegestützte Direktreduktion unter Nutzung erneuerbarer Energien untersucht. Gegenwärtig wird Roheisen nahezu ausschließlich über die Hochofenroute hergestellt. Der Sauerstoff aus dem Eisenerz wird dabei mittels Koks reduziert, wobei CO2 entsteht. Eine großtechnische Alternative ist der sog. Direktreduktionsprozess (Direct Reduced Iron - DRI), bei dem zwar ebenfalls CO2 als Nebenprodukt entsteht, allerdings deutlich weniger, weil als Reduktionsmittel Erdgas verwendet wird. Bei der Reaktion entsteht Wasserstoff, der ebenfalls mit dem Sauerstoff des Eisenoxids (zu Wasser) reagiert, wodurch weniger Sauerstoff mit dem Kohlenstoff zu CO2 umgewandelt wird. Zukünftig kann dieser Prozess ohne fossile Energieträger auskommen. Dafür werden die für den Reduktionsprozess entscheidenden Gase (Wasserstoff und Kohlenstoffmonoxid) mittels Hochtemperaturelektrolyse (Solid Oxide Electrolysis) bereitgestellt. Da die Beimischung prozesstechnisch nur bis zu einem Anteil von 70 Vol.-% sinnvoll ist, hat das Fraunhofer IKTS neuartiges Prozesskonzept entwickelt. Sie nutzen die Fähigkeit der Hochtemperaturelektrolyse auch CO2 umzuwandeln. Im Direktreduktionsprozess ohnehin abgetrenntes Kohlenstoffdioxid wird dem Elektrolyseur mit Wasser zugeführt. So entstehen die beiden Reduktionsmittel Kohlenmonoxid und Wasserstoff. Bei gleichem Substitutionsanteil können so die CO2 Emissionen im Vergleich zur reinen Wasserstoffsubstitution noch weiter gesenkt werden, was die benötigte Energiemenge deutlich reduziert. Der Prozesstechnische Grenzwert kann dadurch von 70 auf 85 vol. -% verschoben werden, wodurch noch weniger Erdgas benötigt wird. Große Potenziale für die Klimaschutzziele bietet darüber hinaus die Tatsache, dass bei eine Erdgassubstitution von mehr als 70 vol.-% das gekoppelte System aus Hochtemperaturelektrolyse und Direktreduktionsanlage die Roheisenproduktion sogar als CO2 Senke betrieben werden kann. Damit ist zukünftig auch der komplette Verzicht auf fossile Kohlenstoffträger möglich.
Das Projekt "Teilprojekt 8: Online LIBS-Analyse" wird vom Umweltbundesamt gefördert und von LTB Lasertechnik Berlin GmbH durchgeführt. Ziel des Projekts ist die Erforschung eines Verfahrens zur Rückgewinnung von Sekundärmetallen und Zementen aus sog. LD-Schlacken. . Die Anwendung dieses Verfahrens und die Verwertung der entstehenden Sekundärrohstoffe in der Stahl- und Zementindustrie soll erheblich zur Einsparung von Primärrohstoffen und zur Reduzierung von Treibhausgasemissionen führen. LD-Schlacken werden bei der Stahlherstellung als Nebenprodukte erzeugt. Sie enthalten prozessbedingt bis zu 30 M.-% Eisenoxid und werden u.a. als Stückschlacke im Straßen-, Erd- und Wasserbau verwertet. Problematisch ist die mangelnde Raumstabilität bei hohen Anteilen an freiem CaO, wodurch der Einsatz von LD-Schlacken auf wenige Anwendungsgebiete eingeschränkt ist. Im Projekt SlagCEM wird die gezielte reduzierende Nachbehandlung der schmelzflüssigen LD-Schlacke untersucht und ein Verfahren für deren vollständige Verwertung in Form von Roheisen und hochwertigem Zementklinker erforscht. Es werden Untersuchungen zur optimalen Einstellung der Zusammensetzung der Schmelze in Hinblick auf die Verwertungseigenschaften und die technisch-/wirtschaftliche Realisierbarkeit vorgenommen. Die experimentellen Untersuchungen reichen vom Labormaßstab bis hin zu Versuchskampagnen im kleintechnischen Lichtbogenofen. Auf dieser Grundlage erfolgen Versuche auf großtechnischer Ebene. Die Hydratationseigenschaften der nachbehandelten LD-Schlacke werden grundlegend untersucht und darüber hinaus mit genormten Methoden auf verschiedene Anwendungspotentiale als Zementklinkerersatz getestet. Die Planung der großmaßstäblichen Umsetzung auf dem Stahlwerksstandort ist ein Kernziel des Projekts. Zur Erreichung dieses Ziels müssen werkstoffliche, technische und logistische Fragestellungen beantwortet und gelöst werden. Die Umweltwirkungen dieser Verwertungsoption für LD-Schlacken müssen eingehend untersucht und durch die Erstellung einer Ökobilanz bewertet werden.
Das Projekt "Teilprojekt A" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Institut für Nukleare Entsorgung (INE) durchgeführt. Ziel des Vorhabens ist es einen Beitrag zur sicheren Endlagerung hochradioaktiven Abfalls zu leisten. In diesem Kontext wollen wir ein auf atomarer Skala basierendes Prozessverständnis der Wechselwirkung von Actiniden und Spaltprodukten mit endlagerrelevanten Mineralen bzw. Mineraloberflächen erlangen, um so Retentionsmechanismen auf langen Zeitskalen zu verstehen. Dazu sind innerhalb des Gesamtprojekts folgende Arbeitspakete vorgesehen: a) Dreiwertige Actinide Pu, Am, Cm (Phosphate, Carbonate, Eisen(hydr)oxide) b) Vierwertige Actiniden Th, U, Np, Pu (Silicate, Sulfate, Carbonate, Phosphate, Sulfide, Eisen(hydr)oxide, LDH-Phasen) a) Cm(III), Am(III) und Eu(III) dotierte Calcite werden synthetisiert und die Besetzung der unterschiedlichen 'sites' wird mit Hilfe der TRLFS quantifiziert. Die maximale Beladung der Sekundärphase mit Actiniden wird aus diesen Daten extrapoliert werden. Mit dreiwertigen Actiniden und Lanthaniden dotierte Calcit Einkristalle werden nach ihrer Synthese an der Beamline in Argonne untersucht. Mit diesen Röntgenreflektometriemessungen wird die Struktur der Oberfläche der Calcitkristalle bestimmt. b) Th(IV) und Np(IV) dotierte Calcite werden im MFR synthetisiert. Einbau sowie Freisetzung der Actiniden wird quantifiziert und modelliert. Der Einfluss von Fremdionen auf die Bildung der An(IV):Calcit 'solid solutions' wird mit Hilfe von SEM und AFM untersucht. Durch XAS werden die Strukturparameter der Einbauspezies bestimmt.
Das Projekt "Sub project: Coupling and competitiveness of iron-, sulfate-, and CO2-reduction along gradients" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Geowissenschaften, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Hydrologie durchgeführt. The relevance of biogeochemical gradients for turnover of organic matter and contaminants is yet poorly understood. This study aims at the identification and quantification of the interaction of different redox processes along gradients. The interaction of iron-, and sulfate reduction and methanogenesis will be studied in controlled batch and column experiments. Factors constraining the accessibility and the energy yield from the use of these electron acceptors will be evaluated, such as passivation of iron oxides, re-oxidation of hydrogen sulfide on iron oxides. The impact of these constraints on the competitiveness of the particular process will then be described. Special focus will be put on the evolution of methanogenic conditions in systems formerly characterized by iron and sulfate reducing condition. As methanogenic conditions mostly evolve from micro-niches, methods to study the existence, evolution and stability of such micro-niches will be established. To this end, a combination of Gibb's free energy calculations, isotope fractionation and tracer measurements, and mass balances of metabolic intermediates (small pool sizes) and end products (large pool sizes) will be used. Measurements of these parameters on different scales using microelectrodes (mm scale), micro sampling devices for solutes and gases (cm scale) and mass flow balancing (column/reactor scale) will be compared to characterize unit volumes for organic matter degradation pathways and electron flow. Of particular interest will be the impact of redox active humic substances on the competitiveness of involved terminal electron accepting processes, either acting as electron shuttles or directly providing electron accepting capacity. This will be studied using fluorescence spectroscopy and parallel factor analysis (PARAFAC) of the gained spectra. We expect that the results will provide a basis for improving reactive transport models of anaerobic processes in aquifers and sediments.
Das Projekt "Sub project:The effect of iron(III)-sulfide interactions on electron transfer processes in anoxic aquifers" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Geowissenschaften, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Hydrologie durchgeführt. Strong evidence exists that the oxidation of H2S by ferric (oxyhydr)oxides occurs also in ground water systems and may exert a major role for the sulphur and iron cycle and in particular for the electron and carbon flow in aquifers. To date, no systematic study has been performed that allows to quantitatively assess its significance in such systems. This project aims to fill this gap of knowledge. The extent of the reaction depends on mineral reactivity, which we hypothesize can be expressed in terms of a generalized kinetic model for the full pH range of environmental relvance. This model accounts for the adsorption of H2S at lower pH values and of HS- at circumneutral pH to the neutral ferric (oxyhydr)oxide surface to form the reactive species FeSH. Variations in reactivity may be caused by intrinsic factors such as surface acidity of the iron mineral and solution composition, such as ionic strength and competition with other ions. The overall goals of this project therefore are to demonstrate the validity of this approach in order to quantify the kinetics for abiotic anaerobic H2S oxidation by ferric (oxyhydr)oxides, and to elucidate the role of this process as a precursor reaction for further microbial transformation of sulphur species in the aquifer.
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