Soraya Heuss | Ludwig-Maximilians-Universität München (original) (raw)
Papers by Soraya Heuss
This flyer introduces the activities of the Working Group "Classification and reporting of a... more This flyer introduces the activities of the Working Group "Classification and reporting of anthropogenic resources", as mandated by the COST Action Mining the European Anthroposphere (MINEA). MINEA is a pan-European expert network, which received funding from the COST Association between 2016 and 2020. The network pools knowledge for estimating the future recoverability of raw materials from anthropogenic resources.
Procedia Earth and Planetary Science, 2017
Sanidinites from Laacher See (Eifel, Germany) and the Middle Italian Volcanic Province are ideal ... more Sanidinites from Laacher See (Eifel, Germany) and the Middle Italian Volcanic Province are ideal materials to study the solvothermal transport of Zr. Sanidinites are rare porous magmatic cumulates, found as volcanic ejecta of explosive volcanoes. The gas composition in magma chambers is comparable with that in a combustion chamber of a municipal solid waste incineration (MSWI-) plant. The aggressive gas species like Cl-2, HCl and SOx, resulting from combustion of municipal waste, pose a severe problem because they attack the superheater steel-tubes in MSWI- plants. To prevent corrosion, thermally sprayed yttria-stabilized Zr-oxide layers are used. The adaption of the solvothermal treatment for densification of these ceramics is investigated. This example demonstrates that a profound knowledge of processes in natural systems, e.g. solvothermal crystal growth in volcanites, provides novel solutions for technical applications. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
EGU General Assembly Conference Abstracts, Apr 1, 2018
Saray volcano (SV) is a small stratovolcano of Miocene age located in the northwest of Iran. The ... more Saray volcano (SV) is a small stratovolcano of Miocene age located in the northwest of Iran. The youngest volcanic activity is characterized by the extrusion of an ultrapotassic trachytic lava dome in the center of Saray volcano and a sequence of lavas and block-and-ash flow deposits. Several small domes and plugs within the crater of SV exhibit the youngest stage. They consist of hybrid magmatic rocks marking the transition to lamprophyric dykes that crosscut the trachytic pyroclastic deposits.
Journal of Cleaner Production, 2021
Abstract Mine wastes such as tailings contain minerals that can be valorised. However, their reso... more Abstract Mine wastes such as tailings contain minerals that can be valorised. However, their resource potential remains widely misjudged because of non-standardised assessment and classification methods. The current United Nations Framework Classification for Resources (UNFC) concept is tested for its applicability to metalliferous tailings mining projects from a private mining company’s perspective with economic focus on a scoping study level. For the case study tailings storage facility (TSF) Cabeco do Piao (Portugal), a rehabilitation scenario, and two resource recovery scenarios with low and high degree of tailings valorisation are defined and evaluated. A risk assessment shows that actions are necessary to protect human health and the environment. Material flows are modelled and a discounted cash flow analysis, under consideration of mineral price uncertainty, indicates the project’s economic viability. The application of the UNFC principles exemplifies that they cover a broad range of aspects in contrast to the conventional classification principles of the Committee for Mineral Reserves International Reporting Standards (CRIRSCO) which focus on techno-economic aspects: TSF rehabilitation is identified as a necessary base case and positive socio-environmental impacts are prioritised. However, the resource recovery scenarios cannot be differentiated with the current UNFC concept. The evaluation reveals the necessity for a stronger user guidance in the assessment and classification process. Additionally, a more detailed subcategorisation is required to identify a project’s benefits and barriers, particularly in social and environmental domains. These aspects are essential for the further development of the UNFC concept to achieve its full potential.
Neues Jahrbuch für Mineralogie - Abhandlungen, 1997
Journal of Water Process Engineering, 2017
Due to the global rising demand there is an enormous interest to recover noble metals most effici... more Due to the global rising demand there is an enormous interest to recover noble metals most efficiently from aqueous solutions, in particular industrial wastewater. Herein we demonstrate a new concept to recover Ag and Au from sulfate, chlorine and nitrate containing waters e.g. from catalysis production. Therefore two different treatment procedures, called 2-step ferritization and Lt-delafossite process, are presented which are based on a modified ferrite process. The phase assemblage can be controlled by the adjustment of the reaction parameters. During the 2-step ferritization process, Ag 0 and Au 0 are precipitated within one separate step. The precipitated phases obtained by the Lt-delafossite process are pure delafossite AgFeO 2 and composite particles of Ag 0 , AgFeO 2 and Fe 3 O 4. By using these low energy, fast (< 20 min) and easy to handle precipitation processes, Ag and Au can be recovered to ≥99.99% from wastewater. In consequence, these procedures help to avoid additional waste streams.
Procedia Earth and Planetary Science, 2017
The environment of hot springs located in the western part of Lake Urmia and north of Urmia City,... more The environment of hot springs located in the western part of Lake Urmia and north of Urmia City, NW Iran, is contaminated with boron. Water analysis performed over a period of four years show maximum boron concentrations of 451 mg/l. An area of 250 km² is heavily polluted. The tectonically strongly disturbed metamorphic and sedimentary rocks in this region provide good pathways for the circulation of fluids. The hydrothermal system consists mainly of Na-(SO 4)-HCO 3. The occurrence of boron can be attributed to the interaction of magmatic fluids, related to young volcanic activities in this area. They seem to be the result of an intensive fluid-rock interaction with the metamorphic host-rock, e.g. tourmaline rich gneiss. Hot fluids in the depth of the study area migrate through the fractured rocks and may leach boron during their path to the surface.
Journal of the European Ceramic Society, 2016
Yttria-stabilized zirconia is supposed to be a promising candidate as anti-corrosion coating on s... more Yttria-stabilized zirconia is supposed to be a promising candidate as anti-corrosion coating on steel tubes in waste-to-energy (WTE) plants. Since the formation of low-melting eutectic salt melts on the surface of those tubes is a common process within WTE plants, the performance of yttria-stabilized zirconia under these conditions was evaluated. Beads of 5 wt.-% Y2O3 stabilized zirconia were embedded in an equimolar mixture of KCl-K2SO4-ZnCl2-ZnSO4. In a temperature range between 600 and 700 degrees C under an atmosphere of N-2-2.55 vol.-% HCl-0.45 vol.-% O-2, a dissolution and recrystallization of the zirconia was observed. The driving force of this process is a changing electromotive force in combination with an increasing basicity of the melt, controlled by reactions between melt and atmosphere. With respect to an application as anti-corrosion coating, the recrystallization process can enable the material to act as a self-healing coating. (C) 2016 Elsevier Ltd. All rights reserved.
Journal of Solid State Chemistry, 2016
This study presents a new low temperature synthesis method to obtain pure delafossite (Cu 1 þ Fe ... more This study presents a new low temperature synthesis method to obtain pure delafossite (Cu 1 þ Fe 3 þ O 2) at a temperature of 70°C within 24 h. For the first time delafossite is synthesized solely by precipitation and subsequent ageing process and without usage of any additives controlling the oxidation state of copper. The synthesized material, called LT-delafossite, consists of pure Cu 1 þ Fe 3 þ O 2 exclusive of any side products. Rietveld analysis confirms the presence of both 3R (space group (SG): R-3m) and 2H (SG: P6 3 / mmc) polytypes in LT-delafossite. Electron microscopy images show nanometer-sized hexagonal plates with a diameter o500 nm and a thickness of o30 nm. Measurements of the magnetic susceptibility from 2 K to 350 K in zero-field show one peak ∼18.5 K, which is attributed to an AFM phase transition. Zero-field-cooled magnetization data between À 14 T and þ 14 T at 2 K revealed an s-shape form around the origin having no remanent magnetization.
Journal of Solid State Chemistry, 2016
In this study, we present the mechanism of CuFeO2 formation in aqueous solution at low temperatur... more In this study, we present the mechanism of CuFeO2 formation in aqueous solution at low temperatures <= 90 degrees C, using sulfate salts as reactants. Furthermore, we demonstrate the influence of experimental conditions (alkalization, reaction and ageing temperature and time) on the synthesized nanoparticles. In all cases, GR-SO4, a Fe(II-III) layered double hydroxysulphate (Fe42+Fe23+ (OH)(12)center dot SO4) and Cu2O precipitate first. During further OH- supply GR-SO4 oxidizes and forms Fe10O14(OH)(2), Cu2O and CuFeO2 crystals. Due to the high further CuFeO2 crystals grow at the cost of the unstable intermediate products. The reaction rate increases with increasing ageing temperature, reaction pH and, in particular, NaOH concentrations in the solution. As a result, highly crystalline CuFeO2 (3R and 2H polytypes) nanoparticles showing hexagonal morphology can be synthesized at 70 degrees C within 10 h or at 50 degrees C within 1 week. The formation of 2H polytype is favored by additional OH- supply during the pH-stat time and rather low temperatures. (C) 2015 ELSEVIER. All rights reserved.
Explosive volcanic eruptions release large amounts of particles into the atmosphere. Volcanic ash... more Explosive volcanic eruptions release large amounts of particles into the atmosphere. Volcanic ash, by definition pyroclasts smaller than 2 mm, can be distributed around the globe by prevailing winds. Ash poses hazards to aviation industry by melting in jet turbines, to human health by entering respiration systems and to society by damaging infrastructure. Under certain circumstances, in plumes or pyroclastic density currents, ash particles can cluster together and build ash aggregates. Aggregates range in size from few mm to few cm and may exhibit complex internal stratigraphy. Ash aggregates are heavier and exhibit different aerodynamic properties than the surrounding ash and accordingly fall prematurely than individual ash grains. Ash aggregation is frequently observed in the geologic record and has also been described during eruptions. Still, the physical and/or chemical mechanisms generating the aggregates remain poorly understood. Distinguishing between the three main types of ...
This flyer introduces the activities of the Working Group "Classification and reporting of a... more This flyer introduces the activities of the Working Group "Classification and reporting of anthropogenic resources", as mandated by the COST Action Mining the European Anthroposphere (MINEA). MINEA is a pan-European expert network, which received funding from the COST Association between 2016 and 2020. The network pools knowledge for estimating the future recoverability of raw materials from anthropogenic resources.
Procedia Earth and Planetary Science, 2017
Sanidinites from Laacher See (Eifel, Germany) and the Middle Italian Volcanic Province are ideal ... more Sanidinites from Laacher See (Eifel, Germany) and the Middle Italian Volcanic Province are ideal materials to study the solvothermal transport of Zr. Sanidinites are rare porous magmatic cumulates, found as volcanic ejecta of explosive volcanoes. The gas composition in magma chambers is comparable with that in a combustion chamber of a municipal solid waste incineration (MSWI-) plant. The aggressive gas species like Cl-2, HCl and SOx, resulting from combustion of municipal waste, pose a severe problem because they attack the superheater steel-tubes in MSWI- plants. To prevent corrosion, thermally sprayed yttria-stabilized Zr-oxide layers are used. The adaption of the solvothermal treatment for densification of these ceramics is investigated. This example demonstrates that a profound knowledge of processes in natural systems, e.g. solvothermal crystal growth in volcanites, provides novel solutions for technical applications. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
EGU General Assembly Conference Abstracts, Apr 1, 2018
Saray volcano (SV) is a small stratovolcano of Miocene age located in the northwest of Iran. The ... more Saray volcano (SV) is a small stratovolcano of Miocene age located in the northwest of Iran. The youngest volcanic activity is characterized by the extrusion of an ultrapotassic trachytic lava dome in the center of Saray volcano and a sequence of lavas and block-and-ash flow deposits. Several small domes and plugs within the crater of SV exhibit the youngest stage. They consist of hybrid magmatic rocks marking the transition to lamprophyric dykes that crosscut the trachytic pyroclastic deposits.
Journal of Cleaner Production, 2021
Abstract Mine wastes such as tailings contain minerals that can be valorised. However, their reso... more Abstract Mine wastes such as tailings contain minerals that can be valorised. However, their resource potential remains widely misjudged because of non-standardised assessment and classification methods. The current United Nations Framework Classification for Resources (UNFC) concept is tested for its applicability to metalliferous tailings mining projects from a private mining company’s perspective with economic focus on a scoping study level. For the case study tailings storage facility (TSF) Cabeco do Piao (Portugal), a rehabilitation scenario, and two resource recovery scenarios with low and high degree of tailings valorisation are defined and evaluated. A risk assessment shows that actions are necessary to protect human health and the environment. Material flows are modelled and a discounted cash flow analysis, under consideration of mineral price uncertainty, indicates the project’s economic viability. The application of the UNFC principles exemplifies that they cover a broad range of aspects in contrast to the conventional classification principles of the Committee for Mineral Reserves International Reporting Standards (CRIRSCO) which focus on techno-economic aspects: TSF rehabilitation is identified as a necessary base case and positive socio-environmental impacts are prioritised. However, the resource recovery scenarios cannot be differentiated with the current UNFC concept. The evaluation reveals the necessity for a stronger user guidance in the assessment and classification process. Additionally, a more detailed subcategorisation is required to identify a project’s benefits and barriers, particularly in social and environmental domains. These aspects are essential for the further development of the UNFC concept to achieve its full potential.
Neues Jahrbuch für Mineralogie - Abhandlungen, 1997
Journal of Water Process Engineering, 2017
Due to the global rising demand there is an enormous interest to recover noble metals most effici... more Due to the global rising demand there is an enormous interest to recover noble metals most efficiently from aqueous solutions, in particular industrial wastewater. Herein we demonstrate a new concept to recover Ag and Au from sulfate, chlorine and nitrate containing waters e.g. from catalysis production. Therefore two different treatment procedures, called 2-step ferritization and Lt-delafossite process, are presented which are based on a modified ferrite process. The phase assemblage can be controlled by the adjustment of the reaction parameters. During the 2-step ferritization process, Ag 0 and Au 0 are precipitated within one separate step. The precipitated phases obtained by the Lt-delafossite process are pure delafossite AgFeO 2 and composite particles of Ag 0 , AgFeO 2 and Fe 3 O 4. By using these low energy, fast (< 20 min) and easy to handle precipitation processes, Ag and Au can be recovered to ≥99.99% from wastewater. In consequence, these procedures help to avoid additional waste streams.
Procedia Earth and Planetary Science, 2017
The environment of hot springs located in the western part of Lake Urmia and north of Urmia City,... more The environment of hot springs located in the western part of Lake Urmia and north of Urmia City, NW Iran, is contaminated with boron. Water analysis performed over a period of four years show maximum boron concentrations of 451 mg/l. An area of 250 km² is heavily polluted. The tectonically strongly disturbed metamorphic and sedimentary rocks in this region provide good pathways for the circulation of fluids. The hydrothermal system consists mainly of Na-(SO 4)-HCO 3. The occurrence of boron can be attributed to the interaction of magmatic fluids, related to young volcanic activities in this area. They seem to be the result of an intensive fluid-rock interaction with the metamorphic host-rock, e.g. tourmaline rich gneiss. Hot fluids in the depth of the study area migrate through the fractured rocks and may leach boron during their path to the surface.
Journal of the European Ceramic Society, 2016
Yttria-stabilized zirconia is supposed to be a promising candidate as anti-corrosion coating on s... more Yttria-stabilized zirconia is supposed to be a promising candidate as anti-corrosion coating on steel tubes in waste-to-energy (WTE) plants. Since the formation of low-melting eutectic salt melts on the surface of those tubes is a common process within WTE plants, the performance of yttria-stabilized zirconia under these conditions was evaluated. Beads of 5 wt.-% Y2O3 stabilized zirconia were embedded in an equimolar mixture of KCl-K2SO4-ZnCl2-ZnSO4. In a temperature range between 600 and 700 degrees C under an atmosphere of N-2-2.55 vol.-% HCl-0.45 vol.-% O-2, a dissolution and recrystallization of the zirconia was observed. The driving force of this process is a changing electromotive force in combination with an increasing basicity of the melt, controlled by reactions between melt and atmosphere. With respect to an application as anti-corrosion coating, the recrystallization process can enable the material to act as a self-healing coating. (C) 2016 Elsevier Ltd. All rights reserved.
Journal of Solid State Chemistry, 2016
This study presents a new low temperature synthesis method to obtain pure delafossite (Cu 1 þ Fe ... more This study presents a new low temperature synthesis method to obtain pure delafossite (Cu 1 þ Fe 3 þ O 2) at a temperature of 70°C within 24 h. For the first time delafossite is synthesized solely by precipitation and subsequent ageing process and without usage of any additives controlling the oxidation state of copper. The synthesized material, called LT-delafossite, consists of pure Cu 1 þ Fe 3 þ O 2 exclusive of any side products. Rietveld analysis confirms the presence of both 3R (space group (SG): R-3m) and 2H (SG: P6 3 / mmc) polytypes in LT-delafossite. Electron microscopy images show nanometer-sized hexagonal plates with a diameter o500 nm and a thickness of o30 nm. Measurements of the magnetic susceptibility from 2 K to 350 K in zero-field show one peak ∼18.5 K, which is attributed to an AFM phase transition. Zero-field-cooled magnetization data between À 14 T and þ 14 T at 2 K revealed an s-shape form around the origin having no remanent magnetization.
Journal of Solid State Chemistry, 2016
In this study, we present the mechanism of CuFeO2 formation in aqueous solution at low temperatur... more In this study, we present the mechanism of CuFeO2 formation in aqueous solution at low temperatures <= 90 degrees C, using sulfate salts as reactants. Furthermore, we demonstrate the influence of experimental conditions (alkalization, reaction and ageing temperature and time) on the synthesized nanoparticles. In all cases, GR-SO4, a Fe(II-III) layered double hydroxysulphate (Fe42+Fe23+ (OH)(12)center dot SO4) and Cu2O precipitate first. During further OH- supply GR-SO4 oxidizes and forms Fe10O14(OH)(2), Cu2O and CuFeO2 crystals. Due to the high further CuFeO2 crystals grow at the cost of the unstable intermediate products. The reaction rate increases with increasing ageing temperature, reaction pH and, in particular, NaOH concentrations in the solution. As a result, highly crystalline CuFeO2 (3R and 2H polytypes) nanoparticles showing hexagonal morphology can be synthesized at 70 degrees C within 10 h or at 50 degrees C within 1 week. The formation of 2H polytype is favored by additional OH- supply during the pH-stat time and rather low temperatures. (C) 2015 ELSEVIER. All rights reserved.
Explosive volcanic eruptions release large amounts of particles into the atmosphere. Volcanic ash... more Explosive volcanic eruptions release large amounts of particles into the atmosphere. Volcanic ash, by definition pyroclasts smaller than 2 mm, can be distributed around the globe by prevailing winds. Ash poses hazards to aviation industry by melting in jet turbines, to human health by entering respiration systems and to society by damaging infrastructure. Under certain circumstances, in plumes or pyroclastic density currents, ash particles can cluster together and build ash aggregates. Aggregates range in size from few mm to few cm and may exhibit complex internal stratigraphy. Ash aggregates are heavier and exhibit different aerodynamic properties than the surrounding ash and accordingly fall prematurely than individual ash grains. Ash aggregation is frequently observed in the geologic record and has also been described during eruptions. Still, the physical and/or chemical mechanisms generating the aggregates remain poorly understood. Distinguishing between the three main types of ...