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Steine-Erden\Ziegel-Mauer-DE-2000

Eingabe Porosierungsmittel als Sägespäne; Korrektur CO2-Emissionen von 180 auf 148 kg/t (Sägespäneanteil:32 kg/t) Herstellung von Mauerziegeln (Ziegelwerk). Die im Ziegelwerk angelieferten tonhaltigen Rohstoffe werden vor dem Brennen aufbereitet. Dabei werden sie mit Wasser konditioniert und ins Walzwerk gegeben. Heute werden meist ein grobes und ein feines Walzwerk betrieben. Nach den Walzwerken werden die Mineralien durch Strangpresse und Abschneider geformt. Derartig vorbehandelt werden sie in die Trocknungskammer eingebracht, die mit der Abwärme des Brennofens beheizt wird. Im Anschluß werden die Ziegel gebrannt. Häufig wird die Trocknung und der Vorbrand in einem Prozeß mit dem keramischen Brand realisiert. Der Brand erfolgt in den meisten Fällen in kontinuierlich betriebenen Tunnelöfen bei Temperaturen zwischen 1000 und 1200°C. Die gebrannten Ziegel werden luftgekühlt. Die Datenbasis für den Prozeß der Ziegelherstellung in GEMIS bildet die Ökobilanz von Mauerziegeln der deutschen, österreichischen und schweizerischen Ziegelverbände (#1). Sie stützt sich auf die Primärdaten von 12 einzelnen Ziegelwerken. Die Daten wurden im Zeitraum von 1992 bis 1993 ermittelt. Genese der Kennziffern Massenbilanz: Für die Herstellung einer Tonne Ziegel müssen im Mittel ca. 1350 kg Tone in den Prozeß eingebracht werden. Dabei reicht die Spanne in der betrachteten Studie von 1055 kg bis 1725 kg Tonmineralien pro Tonne Ziegel (DACH 1996). Die enormen Differenzen sind auf Schwankungen des Wassergehalts und die Art der Ziegel zurückzuführen. Je nach Wassergehalt werden den Tonen Sand und Natursteinmehl beigemengt. Diese Mengen werden in GEMIS allerdings nicht berücksichtigt. Neben den Tonmineralien werden eine Reihe von Zuschlagsstoffen und Porosierungsmittel eingesetzt. Als Porosierungsmittel werden häufig Sägemehl und Polystyrol verwendet. Ein großer Anteil der Porosierungsstoffe wird über Reststoffe gedeckt. Da die Massenanteile der Porosierungsmittel gering sind, der Anteil von Ziegel zu Ziegel sehr unterschiedlich ist und Reststoffe in der Prozeßkettenanalyse ohne Vorkette bilanziert werden, werden die Porosierungsmittel an dieser Stelle nicht aufgeführt. Die über die Porosierungsmittel bereitgestellte Energie ist jedoch beim Energiebedarf des Prozesses zu berücksichtigen (s.u.) Energiebedarf: Der Energiebedarf der in #1 bilanzierten Werke wird größtenteils über Erdgas und Strom gedeckt. Vereinzelt werden auch Heizöle und Propan als Energieträger eingesetzt. Diese werden in GEMIS nicht bilanziert. Der arithmetisch gemittelte Energiebedarf der bilanzierten Ziegelwerke aufgeteilt nach Energieträgern ist in der folgenden Tabelle dargestellt. Tab.: Energiebedarf zur Herstellung einer Tonne Ziegel getrennt nach Energieträgern (DACH 1996, arithmetisch gemittelt). Energieträger Menge in MJ/t Erdgas 1310 elektr. Strom 150 Die Zuschlagsstoffe, die als Porosierungsmittel dienen, sind ebenfalls als Energieträger zu werten, da sie beim Brennen der Ziegel praktisch vollständig verbrennen., wobei den jeweiligen Heizwerten entsprechende Wärmemengen freigesetzt werden. Die Deckung des Energiebedarfs über Porosierungsmittel schwankt stark von Ziegelwerk zu Ziegelwerk. Arithmetisch gemittelt für die bilanzierten Werke ergibt sich ein Anteil an Endenergie von 620 MJ/t. Die Porosierungsmittel werden in GEMIS ohne Vorkette bilanziert. Prozeßbedingte Luftemissionen: Die prozeßbedingten Luftemissionen wurden für die 12 bilanzierten Werke durch Messungen erfaßt . In GEMIS wird das arithmetische Mittel der einzelnen Werke angesetzt. Die Emissionsfaktoren sind in der folgenden Tabelle dargestellt: Tab.: Emissionsfaktoren der einzelnen Luftschadstoffe pro Tonne gebrannter Ziegel (DACH 1996, arithmetisch gemittelt). Schadstoff Masse in kg/t Ziegel SO2 0,100 NOx 0,260 Staub 0,019 CO2 180,417 CO 0,391 HF 0,003 HCl 0,012 organische Stoffe (gesamt C) 0,063 Die Emissionen, die aus der Bereitstellung des Stromes resultieren, sind dabei noch nicht berücksichtigt. Wasserinanspruchnahme: Der Wasserbedarf beim Mischen und Formen der Rohmaterialien im Prozeß der Ziegelherstellung ist wie der Rohstoffbedarf selbst sehr stark von der Grubenfeuchte der Tone abhängig. Daher kann die eingesetzte Wassermenge stark variieren (#3). Das arithmetische Mittel der für die Ziegelverbände erstellten Ökobilanz ergibt einen Wasserbedarf von 0,1 m³/t Ziegel. Dieser Wert wird in GEMIS übernommen. Abwasserinhaltsstoffe: Bei allen bilanzierten Werken ist der Abwasseranfall zu vernachlässigen (#1). Das eingesetzte Prozeßwasser und die Grubenfeuchte der Tone verdampfen während des Trocknungs- und Brennprozesses (#2). Reststoffe: Bei allen in #1 untersuchten Werken ist die aus der Entsorgung fester Abfälle resultierende Umweltbelastung gering. Daten hierzu wurden daher nicht aufgeführt. Der bei der Ziegelherstellung anfallende Trocken- und Brennbruch wird werksintern wiederverwertet (Beimengen zum Rohton) oder nach einer Weiterverarbeitung verkauft (Tennismehl). Die daraus resultierenden Produkte werden in GEMIS nicht berücksichtigt (s. Allokation). Auslastung: 5000h/a Brenn-/Einsatzstoff: Rohstoffe gesicherte Leistung: 100% Jahr: 2000 Lebensdauer: 20a Leistung: 1t/h Nutzungsgrad: 74,1% Produkt: Baustoffe

Markt für Gold

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 gold production (US): 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. UNDERGROUND MINING: Some ore bodies are more economically mined underground. In this case, a tunnel called an adit or a shaft is dug into the earth. Sort tunnels leading from the adit or shaft, called stopes, are dug to access the ore. The surface containing the ore, called a face, is drilled and loaded with explosives. Following blasting, the broken ore is loaded onto electric trucks and taken to the surface. Once mining is completed in a particular stope, it is backfilled with a cement compound. BENEFICIATION: Bald Mountain Mines: The ore treatment method is based on conventional heap leaching technology followed by carbon absorption. The loaded carbon is stripped and refined in the newly commissioned refinery on site. Water is supplied by wells located on the mine property. Grid power was brought to Bald Mountain Mine in 1996. For this purpose, one 27-kilometre 69 KVA power line was constructed from the Alligator Ridge Mine substation to the grid. Golden Sunlight Mines: The ore treatment plant is based on conventional carbon-in-pulp technology, with the addition of a Sand Tailings Retreatment (STR) gold recovery plant to recover gold that would otherwise be lost to tailings. The STR circuit removes the heavier gold bearing pyrite from the sand portion of the tailings by gravity separation. The gold is refined into doré at the mine. Tailing from the mill is discharged to an impoundment area where the solids are allowed to settle so the water can be reused. A cyanide recovery/destruction process was commissioned in 1998. It eliminates the hazard posed to wildlife at the tailings impoundment by lowering cyanide concentrations below 20 mg/l. Fresh water for ore processing, dust suppression, and fire control is supplied from the Jefferson Slough, which is an old natural channel of the Jefferson River. Ore processing also uses water pumped from the tailings impoundment. Pit water is treated in a facility located in the mill complex prior to disposal or for use in dust control. Drinking water is made available by filtering fresh water through an on-site treatment plant. Electric power is provided from a substation at the south property boundary. North-Western Energy supplies electricity the substation. Small diesel generators are used for emergency lighting. A natural gas pipeline supplies gas for heating buildings, a crusher, air scrubber, boiler, carbon reactivation kiln, and refining furnaces. Cortez Mine: Three different metallurgical processes are employed for the recovery of gold. The process used for a particular ore is determined based on grade and metallurgical character of that ore. Lower grade oxide ore is heap leached, while higher-grade non-refractory ore is treated in a conventional mill using cyanidation and a carbon-in-leach (“CIL”) process. When carbonaceous ore is processed by Barrick, it is first dry ground, and then oxidized in a circulating fluid bed roaster, followed by CIL recovery. In 2002 a new leach pad and process plant was commissioned; this plant is capable of processing 164 million tonnes of heap leach ore over the life of the asset. Heap leach ore production is hauled directly to heap leach pads for gold recovery. Water for process use is supplied from the open pit dewatering system. Approximately 90 litres per second of the pit dewatering volume is diverted for plant use. Electric power is supplied by Sierra Pacific Power Company (“SPPC”) through a 73 kilometre, 120 kV transmission line. A long-term agreement is in place with SPPC to provide power through the regulated power system. The average power requirement of the mine is about 160 GWh/year. REFINING: Wohlwill electrolysis. It is assumed that the gold doré-bars from both mines undergo the treatment of Wohlwill electrolysis. This process uses an electrolyte containing 2.5 mol/l of HCl and 2 mol/l of HAuCl4 acid. Electrolysis is carried out with agitation at 65 – 75 °C. The raw gold is intro-duced as cast anode plates. The cathodes, on which the pure gold is deposited, were for many years made of fine gold of 0.25 mm thickness. These have now largely been replaced by sheet titanium or tantalum cathodes, from which the thick layer of fine gold can be peeled off. In a typical electrolysis cell, gold anodes weighing 12 kg and having dimensions 280×230×12 mm (0.138 m2 surface) are used. Opposite to them are conductively connected cathode plates, arranged by two or three on a support rail. One cell normally contains five or six cathode units and four or five anodes. The maximum cell voltage [V] is 1.5 V and the maximum anodic current density [A] 1500 A/m2. The South African Rand refinery gives a specific gold production rate of 0.2 kg per hour Wohlwill electrolysis. Assuming a current efficiency of 95% the energy consumption is [V] x [A] / 0.2 [kg/h] = 1.63 kWh per kg gold refined. No emissions are assumed because of the purity and the high value of the material processed. The resulting sludge contains the PGM present in the electric scrap and is sold for further processing. OTHER MINES: Information about the technology used in the remaining mines is described in the References. WATER EMISSIONS: Water effluents are discharged into rivers. References: Auerswald D. A. and Radcliffe P. H. (2005) Process technology development at Rand Refinery. In: Minerals Engineering, 18(8), pp. 748-753, Online-Version under: http://dx.doi.org/10.1016/j.mineng.2005.03.011. Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp Renner H., Schlamp G., Hollmann D., Lüschow H. M., Rothaut J., Knödler A., Hecht C., Schlott M., Drieselmann R., Peter C. and Schiele R. (2002) Gold, Gold Alloys, and Gold Compounds. In: Ullmann's Encyclopedia of Industrial Chemistry. Online version, posting date: September 15, 2000 Edition. Wiley-Interscience, Online-Version under: http://dx.doi.org/10.1002/14356007.a12_ 499. Barrick (2006b) Environment: Performance Tables from http://www.barrick. com/Default.aspx?SectionID=8906c4bd-4ee4-4f15-bf1b-565e357c01e1& LanguageId=1 Newmont (2005b) Now & Beyond: Sustainability Reports. Newmont Mining Corporation. Retrieved from http://www.newmont.com/en/social/reporting/ index.asp technologyComment of gold production (CA): 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. UNDERGROUND MINING: Some ore bodies are more economically mined underground. In this case, a tunnel called an adit or a shaft is dug into the earth. Sort tunnels leading from the adit or shaft, called stopes, are dug to access the ore. The surface containing the ore, called a face, is drilled and loaded with explosives. Following blasting, the broken ore is loaded onto electric trucks and taken to the surface. Once mining is completed in a particular stope, it is backfilled with a cement compound. 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. BENEFICIATION: In the Porcupine Mines, gold is recovered using a combination of gravity concentration, milling and cyanidation techniques. The milling process consists of primary crushing, secondary crushing, rod/ball mill grinding, gravity concentration, cyanide leaching, carbon-in-pulp gold recovery, stripping, electrowinning and refining. In the Campbell Mine, the ore from the mine, after crushing and grinding, is processed by gravity separation, flotation, pressure oxidation, cyanidation and carbon-in-pulp process followed by electro-winning and gold refining to doré on site. The Musselwhite Mine uses gravity separation, carbon in pulp, electro¬winning and gold refining to doré on site. REFINING: Wohlwill electrolysis. It is assumed that the gold doré-bars from both mines undergo the treatment of Wohlwill electrolysis. This process uses an electrolyte containing 2.5 mol/l of HCl and 2 mol/l of HAuCl4 acid. Electrolysis is carried out with agitation at 65 – 75 °C. The raw gold is intro-duced as cast anode plates. The cathodes, on which the pure gold is deposited, were for many years made of fine gold of 0.25 mm thickness. These have now largely been replaced by sheet titanium or tantalum cathodes, from which the thick layer of fine gold can be peeled off. In a typical electrolysis cell, gold anodes weighing 12 kg and having dimensions 280×230×12 mm (0.138 m2 surface) are used. Opposite to them are conductively connected cathode plates, arranged by two or three on a support rail. One cell normally contains five or six cathode units and four or five anodes. The maximum cell voltage [V] is 1.5 V and the maximum anodic current density [A] 1500 A/m2. The South African Rand refinery gives a specific gold production rate of 0.2 kg per hour Wohlwill electrolysis. Assuming a current efficiency of 95% the energy consumption is [V] x [A] / 0.2 [kg/h] = 1.63 kWh per kg gold refined. No emissions are assumed because of the purity and the high value of the material processed. The resulting sludge contains the PGM present in the electric scrap and is sold for further processing. WATER EMISSIONS: Effluents are discharged into the ocean. REFERENCES: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp Renner H., Schlamp G., Hollmann D., Lüschow H. M., Rothaut J., Knödler A., Hecht C., Schlott M., Drieselmann R., Peter C. and Schiele R. (2002) Gold, Gold Alloys, and Gold Compounds. In: Ullmann's Encyclopedia of Industrial Chemistry. Online version, posting date: September 15, 2000 Edition. Wiley-Interscience, Online-Version under: http://dx.doi.org/10.1002/14356007.a12_ 499. Auerswald D. A. and Radcliffe P. H. (2005) Process technology development at Rand Refinery. In: Minerals Engineering, 18(8), pp. 748-753, Online-Version under: http://dx.doi.org/10.1016/j.mineng.2005.03.011. technologyComment of gold production (AU): 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. UNDERGROUND MINING: Some ore bodies are more economically mined underground. In this case, a tunnel called an adit or a shaft is dug into the earth. Sort tunnels leading from the adit or shaft, called stopes, are dug to access the ore. The surface containing the ore, called a face, is drilled and loaded with explosives. Following blasting, the broken ore is loaded onto electric trucks and taken to the surface. Once mining is completed in a particular stope, it is backfilled with a cement compound. 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. 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. REFINING: Wohlwill electrolysis. It is assumed that the gold doré-bars from both mines undergo the treatment of Wohlwill electrolysis. This process uses an electrolyte containing 2.5 mol/l of HCl and 2 mol/l of HAuCl4 acid. Electrolysis is carried out with agitation at 65 – 75 °C. The raw gold is intro-duced as cast anode plates. The cathodes, on which the pure gold is deposited, were for many years made of fine gold of 0.25 mm thickness. These have now largely been replaced by sheet titanium or tantalum cathodes, from which the thick layer of fine gold can be peeled off. In a typical electrolysis cell, gold anodes weighing 12 kg and having dimensions 280×230×12 mm (0.138 m2 surface) are used. Opposite to them are conductively connected cathode plates, arranged by two or three on a support rail. One cell normally contains five or six cathode units and four or five anodes. The maximum cell voltage [V] is 1.5 V and the maximum anodic current density [A] 1500 A/m2. The South African Rand refinery gives a specific gold production rate of 0.2 kg per hour Wohlwill electrolysis. Assuming a current efficiency of 95% the energy consumption is [V] x [A] / 0.2 [kg/h] = 1.63 kWh per kg gold refined. No emissions are assumed because of the purity and the high value of the material processed. The resulting sludge contains the PGM present in the electric scrap and is sold for further processing. WATER EMISSIONS: Water effluents are discharged into rivers. REFERENCES: Newmont (2004) How gold is mined. Newmont. Retrieved from http://www.newmont.com/en/gold/howmined/index.asp Renner H., Schlamp G., Hollmann D., Lüschow H. M., Rothaut J., Knödler A., Hecht C., Schlott M., Drieselmann R., Peter C. and Schiele R. (2002) Gold, Gold Alloys, and Gold Compounds. In: Ullmann's Encyclopedia of Industrial Chemistry. Online version, posting date: September 15, 2000 Edition. Wiley-Interscience, Online-Version under: http://dx.doi.org/10.1002/14356007.a12_ 499. Auerswald D. A. and Radcliffe P. H. (2005) Process technology development at Rand Refinery. In: Minerals Engineering, 18(8), pp. 748-753, Online-Version under: http://dx.doi.org/10.1016/j.mineng.2005.03.011. technologyComment of gold production (TZ): The mining of ore from open pit and underground mines is considered. technologyComment of gold refinery operation (ZA): REFINING: The refinery, which provides a same day refining service, employs the widely used Miller Chlorination Process to upgrade the gold bullion it receives from mines to at least 99.50% fine gold, the minimum standard required for gold sold on the world bullion markets. It also employs the world’s leading silver refining technology. To further refine gold and silver to 99.99% the cost-effective once-through Wohlwill electrolytic refining process is used. MILLER CHLORINATION PROCESS: This is a pyrometallurgical process whereby gold dore is heated in furnace crucibles. The process is able to separate gold from impurities by using chlorine gas which is added to the crucibles once the gold is molten. Chlorine gas does not react with gold but will combine with silver and base metals to form chlorides. Once the chlorides have formed they float to the surface as slag or escape as volatile gases. The surface melt and the fumes containing the impurities are collected and further refined to extract the gold and silver. This process can take up to 90 minutes produces gold which is at least 99.5% pure with silver being the main remaining component. This gold can be cast into bars as 99.5% gold purity meets the minimum London Good Delivery. However some customers such as jewellers and other industrial end users require gold that is almost 100% pure, so further refining is necessary. In this case, gold using the Miller process is cast into anodes which are then sent to an electrolytic plant. The final product is 99.99% pure gold sponge that can then be melted to produce various end products suited to the needs of the customer. WOHLWILL PROCESS - The electrolytic method of gold refining was first developed by Dr. Emil Wohlwill of Norddeutsche Affinerie in Hamburg in 1874. Dr. Wohlwill’s process is based on the solubility of gold but the insolubility of silver in an electrolyte solution of gold chloride (AuCl3) in hydrochloric acid. Figure below provide the overview of the refining process (source Rand Refinery Brochure) imageUrlTagReplace7f46a8e2-2df0-4cf4-99a8-2878640be562 Emissions includes also HCl to air: 7.48e-03 Calculated from rand refinery scrubber and baghouse emmission values Metal concentrators, Emmision report 2016 http://www.environmentalconsultants.co.za/wp-content/uploads/2016/11/Appendix-D1.pdf technologyComment of gold refinery operation (RoW): REFINING: The refinery, which provides a same day refining service, employs the widely used Miller Chlorination Process to upgrade the gold bullion it receives from mines to at least 99.50% fine gold, the minimum standard required for gold sold on the world bullion markets. It also employs the world’s leading silver refining technology. To further refine gold and silver to 99.99% the cost-effective once-through Wohlwill electrolytic refining process is used. MILLER CHLORINATION PROCESS: This is a pyrometallurgical process whereby gold dore is heated in furnace crucibles. The process is able to separate gold from impurities by using chlorine gas which is added to the crucibles once the gold is molten. Chlorine gas does not react with gold but will combine with silver and base metals to form chlorides. Once the chlorides have formed they float to the surface as slag or escape as volatile gases. The surface melt and the fumes containing the impurities are collected and further refined to extract the gold and silver. This process can take up to 90 minutes produces gold which is at least 99.5% pure with silver being the main remaining component. This gold can be cast into bars as 99.5% gold purity meets the minimum London Good Delivery. However some customers such as jewellers and other industrial end users require gold that is almost 100% pure, so further refining is necessary. In this case, gold using the Miller process is cast into anodes which are then sent to an electrolytic plant. The final product is 99.99% pure gold sponge that can then be melted to produce various end products suited to the needs of the customer. WOHLWILL PROCESS - The electrolytic method of gold refining was first developed by Dr. Emil Wohlwill of Norddeutsche Affinerie in Hamburg in 1874. Dr. Wohlwill’s process is based on the solubility of gold but the insolubility of silver in an electrolyte solution of gold chloride (AuCl3) in hydrochloric acid. Figure below provide the overview of the refining process (source Rand Refinery Brochure) imageUrlTagReplace7f46a8e2-2df0-4cf4-99a8-2878640be562 Emissions includes also HCl to air: 7.48e-03 Calculated from rand refinery scrubber and baghouse emmission values Metal concentrators, Emmision report 2016 http://www.environmentalconsultants.co.za/wp-content/uploads/2016/11/Appendix-D1.pdf technologyComment of gold-silver mine operation with refinery (PG): 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 recovery processes of the Misima Mine are cyanide leach and carbon in pulp (CIP). 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: The recovery process in the Porgera Mine is pressure oxidation and cyanide leach. 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. WATER SUPPLY: For Misima Mine, process water is supplied from pit dewatering bores and in-pit water. Potable water is sourced from boreholes in the coastal limestone. For Porgera Mine, the main water supply of the mine is the Waile Creek Dam, located approximately 7 kilometres from the mine. The reservoir has a capacity of approximately 717, 000 m3 of water. Water for the grinding circuit is also extracted from Kogai Creek, which is located adjacent to the grinding circuit. The mine operates four water treatment plants for potable water and five sewage treatment plants. ENERGY SUPPLY: For Misima Mine, electricity is produced by the mine on site or with own power generators, from diesel and heavy fuel oil. For Porgera Mine, electricity is produced by the mine on site. Assumed with Mobius / Wohlwill electrolysis. Porgera's principal source of power is supplied by a 73-kilometre transmission line from the gas fired and PJV-owned Hides Power Station. The station has a total output of 62 megawatts (“MW”). A back up diesel power station is located at the mine and has an output of 13MW. The average power requirement of the mine is about 60 MW. For both Misima and Porgera Mines, an 18 MW diesel fired power station supplies electrical power. Diesel was used in the station due to the unavailability of previously supplied heavy fuel oil. technologyComment of gold-silver mine operation with refinery (CA-QC): One of the modelled mine is an open-pit mine and the two others are underground. technologyComment of gold-silver mine operation with refinery (RoW): The mining of ore from open pit mines is considered. 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 processing of anode slime from electrorefining of copper, anode (GLO): Based on typical current technology. Anode slime treatment by pressure leaching and top blown rotary converter. Production of Silver by Möbius Electrolysis, Gold by Wohlwill electrolysis, copper telluride cement and crude selenium to further processing. technologyComment of silver-gold mine operation with refinery (CL): 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. BENEFICIATION: The processing plant consists of primary crushing, a pre-crushing circuit, (semi autogenous ball mill crushing) grinding, leaching, filtering and washing, Merrill-Crowe plant and doré refinery. The Merrill-Crowe metal recovery circuit is better than a carbon-in-pulp system for the high-grade silver material. Tailings are filtered to recover excess water as well as residual cyanide and metals. A dry tailings disposal system was preferred to a conventional wet tailings impoundment because of site-specific environmental considerations. technologyComment of silver-gold mine operation with refinery (RoW): Refinement is estimated with electrolysis-data. technologyComment of treatment of precious metal from electronics scrap, in anode slime, precious metal extraction (SE, RoW): Anode slime treatment by pressure leaching and top blown rotary converter. Production of Silver by Möbius Electrolysis, Gold by Wohlwill electrolysis, Palladium to further processing

Markt für Antimon

technologyComment of antimony production (CN, RoW): The data represent a mixture of blast furnace, rotry kiln and electrowinning process. It is approximated from lead smelting

Einbindung von Blei und Zink in den Zementklinker und ihr Einfluss auf das Erstarren und Erhaerten

Das Projekt "Einbindung von Blei und Zink in den Zementklinker und ihr Einfluss auf das Erstarren und Erhaerten" wird vom Umweltbundesamt gefördert und von Forschungsinstitut der Zementindustrie durchgeführt. In der Bundesrepublik fallen jaehrlich ueber 3 Millionen Tonnen Sonderabfaelle wie z.B. Altreifen, Saeureharz und Bleicherden an, die neben umweltrelevanten Stoffen verbrennbare Substanzen enthalten. Eine Nutzung dieser Stoffe als Brennstoff ist moeglich, wenn die darin enthaltenen umweltrelevanten Bestandteile wie z.B. Schwefel, Blei und Zink im Zementklinker gebunden werden und dessen Qualitaet dadurch nicht beeinflusst wird. Das Forschungsvorhaben soll Aufschluss ueber das Verhalten von Blei und Zink im Zementofen und ueber die Auswirkung auf das Erstarren und Erhaerten des Zements geben.

Verbrennung von Kohle fuer das Brennen von Ziegelsteinen

Das Projekt "Verbrennung von Kohle fuer das Brennen von Ziegelsteinen" wird vom Umweltbundesamt gefördert und von Gebrüder Löhlein Ziegelwerke durchgeführt. Objective: To convert a brick kiln fired with heavy oil to coal firing and to examine the effects of the burning of coal on the specific heat consumption, the quality of the product and the occurring ashes. On the basis of preliminary examinations on other kilns, an energy saving of more than 55 per cent is anticipated compared with oil-firing. General Information: The brick tunnel kiln to be converted to coal firing is to be equipped with an intermittent coal firing facility and tested. For this purpose, the necessary coal preparation facilities (feed bunker, transport systems, hammer mill, daily bunker and coal stokers at the blowing in points) and the special burner systems are to be developed and adapted to suit the specified tunnel kiln. The overall system will then be tested and, if necessary, modified depending on the product quality. Finally, the operating efficiency of the coal firing facility is to be tested during a longer demonstration operation period. The concept for the coal firing facility was based on the use and testing or different types of coal with various grain sizes to be able to optimize the requirements on coal quality and grain size both for separation and charging. The driest possible fine coal with a grain size of 0 - 6 mm is necessary for the blowing device. The erected preparation facilities comprise a feed bunker, from which the rough coal is conveyed to the hammer mill via a dispatch belt. After being ground to the necessary grain size, the fine coal is transported by pipe chain conveyers to the dosing appliances on the tunnel kiln in the form of coal stockers. They intermittently charge a coal-air mixture into the combustion planes of the kiln through lateral slits via so-called guide tubes. The ends of the tubes, which are fitted with baffle plates, protrude into the combustion channel. They are incandescent (hot bulb ignition) and cause the ignition of the mixture. Charging is effected in a 30-second rhythm alternating with every fourth row of the burner tubes. In the cases of intermittent charging, the coal-air mixture is pressed against the baffle plate with a high pressure and passes into the furnace area via the lateral slits in the incandescent tubes. Combustion is almost explosive. The intermittent control of the air feed is effected by a central closed-loop control facility via solenoid valves. Achievements: In a 26 week operation period, a mean fuel consumption of 1500 kJ/kg of fired bricks including drying was achieved. This corresponds to an energy saving of about 42 per cent when compared to operation with heavy heating oil. Although the target was not achieved, a considerable saving quota was realized. In the meantime, the facility has been demonstrated to several hundred interested parties from the brick industry and has therefore made an important contribution to the necessary spread of the experience and information gained in the course of this project.

Gas-fuelled rapid heating furnace

Das Projekt "Gas-fuelled rapid heating furnace" wird vom Umweltbundesamt gefördert und von Gaswärme-Institut e.V. durchgeführt. Objective: To demonstrate the feasibility of reducing energy consumption in the reheating of forgings and to improve forging quality by the replacement of electric and conventional gas-fired furnaces, by a new gas-fuelled rapid heating furnace incorporating and combining known technical features: these will considerably reduce energy consumption and advance the engineering design of conventional gas-fired reheating furnaces. General Information: Rapid heating furnaces are often installed in forging shops to treat small forgings. It is important to heat the forging rapidly and evenly and to minimize scale formation. The object of this research is to produce a micro-structure to eliminate the need for further heat treatment. The advantage of an inductive, over a conventional gas-fuelled furnace is the low level of scale formation due to the brief furnace dwell time. On the other hand, inductive furnaces are operated by a secondary source of energy (electricity) and are therefore expensive to operate. In addition, temperature distribution in a charge heated by a conventional furnace is unsatisfactory. The furnace to be designed, installed and operated for the project is a gas fuelled rapid heating installation using natural gas as the primary energy source. Charge heating will be in 3 zones (soaking, heating-up and preheating) to reheat the charge. As in the case of pusher type furnaces, charge and atmosphere movement will be counter current. In order to minimize scale formation, the soaking zone will be fired in the fuel-rich mode, while the heating-up zone will be fuelled by a fuel-lean gas and air mixture, burning uncombusted gases from the soaking zone. Staged combustion minimizes NO output and environmental impact. Fuel-rich soaking zone operation necessitates tests to establish combustion air preheat temperature, the acceptability of the fuel/air system with respect to sooting and safety aspects associated with CO formation. Forgings will be charged in transverse mode and a recuperator incorporated in the furnace for combustion air preheating: the furnace control system will feature high precision fuel/air ration controllers for heating-up and soaking zones. Each controller is capable of maintaining an air factor of between 0.5 and 1.5 to allow exact adjustment of the fuel/air ratio and to minimize scaling. An optical control system monitors the temperature of the charge leaving the furnace. Fuel gas flow is adjusted by temperature controller as a function of the difference between temperature as measured by the optical system and set point temperature. When fuel gas flow is adjusted, combustion air flow will also be adjusted by the fuel/air ratio control system. A shop function is also incorporated in the furnace control system: this is capable of lowering gas flow to between to 10-30 per cent of rated flow. For this purpose the control system will immediately reduce gas flow if furnace operation is switched to idle mode. Simultaneously...

Upcycling von Gummireststoffen

Drei Millionen Tonnen Altreifen fallen in Europa jährlich an. Im EU-Projekt TyGRE (High added value materials from waste Tyre Gasification Residues) wird seit 2011 erforscht, wie verhindert werden kann, dass diese lediglich auf Deponien gelagert, in Brennöfen der Zementindustrie verheizt oder zu Granulat und Gummimehl für den Einsatz in Straßenbelägen vermahlen werden. Verfahren zur Reifenverwertung sind Pyrolyse und Vergasung, beide Prozesse erzeugen einen Gasstrom, der zwar ebenfalls als Brennstoff, aber auch für chemische Reaktionen verwendet werden kann. Der Gesamtprozess erweist sich allerdings nur als wirtschaftlich, wenn das Nebenprodukt verwendet wird, ein kohlenstoffhaltiger Feststoff, der bisher als Füllstoff in Neureifen und als Aktivkohle getestet wurde. Als Alternative wird an den Vergasungsprozess ein Schritt gekoppelt, in dem durch Plasmasynthese Siliziumkarbid produziert wird, das bei der Herstellung von Keramikmaterial und in elektronischen Anwendungen seinen Einsatz findet. Am italienischen Institut für Neue Technologien, Energie und Umwelt (ENEA) entsteht derzeit ein Prototyp der Recyclinganlage, die anfangs 30 Kilogramm Altreifen pro Stunde verarbeiten soll. Anstatt das Gummi aus Altreifen für den Einsatz in Straßenbelägen und Sportplatzböden zu vermahlen, kann Gummimehl nach einer Erfindung von Prof. Rainer Stich von der Hochschule für Technik, Wirtschaft und Kultur Leipzig auch zu einem Abdichtungsprodukt für den Bau verarbeitet werden. Das erste wasserundurchlässige Abdichtungsprodukt auf Gummi- statt auf Bitumenbasis ist seit 2010 für die Verwendung als Bauwerksabdichtung von einer zertifizierten Prüfstelle durch ein allgemeines bauaufsichtliches Prüfzeugnis als Flüssigkunststoff zugelassen. Bereits in der Produktion setzt die Firma Ruhr Compounds GmbH an, die Produktionsreste aus der gummiverarbeitenden Industrie in Form von Elastomerpulvern in einem selbst entwickelten Verfahren zum Upcycling nutzt. Daraus wird der hochwertige Kunststoff EPMT (Elastomerpulver Modifizierte Thermoplaste) gewonnen. Er spart Rohstoffkosten und ermöglicht es, aus recyceltem Gummi hochwertige Produkte wie Rad- und Spritzschutzkappen, Griffe oder Transportrollen herzustellen. Dabei sind Härten von gummiartig-weich bis kunststoffartig-hart realisierbar. EPMT können auf marktüblichen Spritzgussund Extrusionsanlagen verarbeitet werden und sind selbst rezyklierbar.

Beheizung von Gebaeuden und Wasser mit der Abwaerme einer Zementfabrik

Das Projekt "Beheizung von Gebaeuden und Wasser mit der Abwaerme einer Zementfabrik" wird vom Umweltbundesamt gefördert und von INTERATOM durchgeführt. Objective: Partial utilization of rotary kiln jacket waste heat to heat buildings and water for industrial use, by way of a radiation absorber. Concurrently a measuring programme is to take place for the long term evaluation of the following: - availability; - operating behaviour; - influencing kiln jacket temperature; - real energy saving costs; - operating costs; - commercial efficiency. Annual heating oil saving of +-130,000 litres is anticipated. General Information: Absorber design is to the following specifications: - heat transfer surface 103 m2; - length 6 m; - power at 370 deg C jacket; - temperature 650 kW; - power at 300 deg C jacket; - temperature 400 kW. The absorber is comprised of 12 single, level heat exchanger thermo plates. The plates are coated with black absorbent lacquer on the kiln side and equipped with weather-proof thermal insulation on the rear. The absorber plates, mounted on 2 swivel steel constructions, form two heptagonal half-shells completely enclosing the kiln over a length of 6 m at a distance of 0,5 m. The absorber loop absorbs heat from the radiation absorber, transferring it to hydraulically decoupled heating loops via three intermediate heat exchangers. A glycol-water mixture acts as heat transfer medium in the absorber loop. If less heat is required inlet temperature is limited by a 3-way valve whereby heat surplus to requirements is discharged to the cooling loop. In normal circumstances the absorber provides 100 per cent of the heat supply. The intermediate heat exchanger is by-passed at temperatures below 60 deg. C. In the event of heating loop failure the cooling loop acts as emergency cooling system and is designed for removal of total absorber output. Achievements: Acceptance tests were performed on the radiation absorber for different inlet temperatures of the heat transfer medium into the absorber, and for different absorber positions. Relevant input data for the absorber were inlet and outlet temperatures at the absorber, and its throughput. At a measuring cycle of two measures/min. power was recorded. The average hourly power was automatically printed. Kiln temperature was measured in the vicinity of the absorber at initially three, then five and in most cases seven almost equidistant positions. Kiln shell temperature was between 256 deg.C and 369 deg.C; absorber power, at different positions and inlet temperatures, was between 121 kW and 401 kW. The fact that the anticipated power of 600 kW was not achieved is due primarily to the inadequate tightness of the absorber system, in particular at the lower and upper 12 cm gap between the half shells. A vertical flow velocity of 2 m/s was measured there with an anemometer. With heat transfer coefficients of 6.4W/m2K for the kiln and 5.7W/m2K for the absorber for free connective flow, a convection loss of 180 kW results for the kiln and of 40 kW for the absorber. This is a total of 220 kW. 50 per cent of this can certainly be used with adequate ...

3,5-MW-Waermepumpensystem fuer die Rueckgewinnung von Abwaerme aus Malzdarrprozessen

Das Projekt "3,5-MW-Waermepumpensystem fuer die Rueckgewinnung von Abwaerme aus Malzdarrprozessen" wird vom Umweltbundesamt gefördert und von Malzfabrik Weißheimer durchgeführt. Objective: The project was intended to reduce the energy input for malt drying at the Friedrich Weissheimer Malzfabrik plant at Gelsenkirchen from 67000 MWh a year to 44 000 MWh a year. General Information: The proposal was to install two heat pumps with inputs of 330 kw and 420 kw. These would draw water from the harbour next to the plant through the evaporator system and heat would be transferred via r22 and r12 refrigerant circuits operated by five sabroe smc 16l compressors. The system was planned to operate as a bivalent system, the temperature being boosted through the existing boiler heating plant. Water heat was exchanged in an air heater and this circuit was used to dry the malt in the malt kilns. The plant output was approximately 90 000 tonnes of malt a year which required about 92 000 mwh a year for drying. About 25000 Mwh were available via the existing heat recovery system. The heat pump installation was planned to contribute a further 23000 Mwh a year for the use of approximately 5 500 Mwh a year of electricity. The system was the result of considerable investigation and planning by messes. Weissheimer in association with Dr.-Ing. Harald Steinhaus of Att Energietechnik. The project, which was a refinement of previous suggestions to use an electricity powered heat pump system, was particularly attractive because harbour water at a relatively high temperature designed for 18 deg.C was available. The Gelsenkirchen site was near other industrial premises, particulary a refinery. Emission from these premises raised the water temperature locally. The system was built and installed during the latter half of 1981 and the beginning of 1982. The main heat pump installation was the responsibility of Sabroe Kältetechnik GmbH of Flensburg. The targets were to integrate the system during the first half of 1982 and operate the demonstration programme between June-July 1982 and June-July 1983. In the event a series of problems meant that the plant was not judged to be properly integrated into the malt production process until July 1983. Achievements: At the beginning of August 1983, the heat pump system had to be taken out of operation owing to an evaporator fault which turned out to be irreparable. The cause of the corrosion damage to the evaporator could not to be fully ascertained, although it soon became evident that replacement in the original (copper) material was not to be considered. Since it was not possible to recommission the plant in its original form (due to the high cost) it was decided to convert the heat pump system to use waste heat from the refrigeration systems. By optimising the integration of the heat pump system into the production process it was possible to increase the number of hours of its operation from +/- 18 h/d in 1982 to +/- 22 h/d in mid-1983. As a result of restrictions in the available power supply (+/- 2500 kW) useful heat pump output was around 2 to 3 MW on simultaneous operation of the refrigeration ...

Recovery of process heat from the combustion of oxygen-containing solvents in package lacquer driers

Das Projekt "Recovery of process heat from the combustion of oxygen-containing solvents in package lacquer driers" wird vom Umweltbundesamt gefördert und von Heinrich Neitz GmbH Industrieöfen durchgeführt. Objective: Reduction of energy costs in drying of packing varnishes through a recovery of process heat from the combustion of recovered solvents and its utilization for heating the drier plant. The calculated energy savings are assumed to amount to approx. 4500000 kW/year. General Information: The innovative technology consists of a combination of individual technological solutions. These include the condensation of solvents, the drying of packing varnish, thermal post-combustion of the exhaust air from the plant (which is rich in carbohydrates), heating of this port-combustion system by using the solvent condensate as fuel, and the utilization of the resulting energy (i.e., pure exhaust air exhibiting a very high temperature) as process heat for drying of packing varnish. Overall plant structure: Evaporation section with heat exchanger and vacuum extraction system; Measuring device for monitoring the solvent concentration; Condensation system for recovery of incoming solvents; Preheating zone with heat exchanger and extraction system; Daking section with heat exchanger and extraction system; Post-combustion system for generating process heat through combustion of the recovered solvents; Cooling section; Air recirculation system between the different sections. This combination of system components causes the exhaust air volume (and hence, the total carbohydrate release rate) to be drastically reduced. The investment cost of this combine plant is about twice as high as that of a conventional system. On the other hand, the total annual energy generating cost for a conventional plant exceeds that of the combined plant by a factor of 1.5. This means that the combined system achieves cost savings between DM 150000 and DM 180000 per year. Assuming that the proceeds from a conventional systems and the combination plant are the same, the capital recovery from a plant of the type envisaged in the project is markedly higher (due to the lower total cost), which considerably shortens the period of amortization. Achievements: The technical and chemical feasibility of the project described in the application could be demonstrated with the conclusion of the design phase. A number of aspects have arisen, however, which may turn the project into a financial failure on the current level of information. One of these facors is the draft of the Accident Prevention Rules for Lacquer Driers (VBG 24) of March 1988, which calls for a considerable reduction in admissible solvent concentrations compared to the older version of these Accident Prevention Rules. With these new, reduced solvent concentrations, the recovery of solvents through condensation is no longer an economically viable proposal. Moreover, the Ministry of the Environment expects the packaging industry to make increasing use of low-solvent lacquers. Renowned packaging manufacturers are already using low-solvent or water soluble varnishes. Plants designed for such applications have already been...

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