Professur für Mineralogie (Prof. Putnis)
Corrensstraße 24, Room 116
Phone: +49 251 83-33451
Fax: +49 251 83-38397
Professur für Mineralogie (Prof. Putnis)
Corrensstraße 24, Room 116
I have two main areas of research:
Phase transformations in minerals (including displacive transformations, order-disorder transformations, and exsolution), with particular reference to the evolution of the microstructure, as studied by transmission electron microscopy (see ICEM) as well as the characterization of structural changes by diffraction and spectroscopic methods. Computational methods and statistical thermodynamic modelling are being used to determine the thermodynamic properties of solid solutions with different degrees of short and long range order.
Mineral Surface Science, which broadly covers the fields of crystal growth and dissolution processes and the role of organic and inorganic additives. We have two atomic force microscopes equiped to study these processes in situ in fluid cells, as well as carrying out macroscopic growth and dissolution experiments.
These two areas (the first, essentially ‘solid state’, the second, essentially mineral-fluid interaction) come together in the more general question of how minerals equilibrate in the presence of a fluid phase. Specifically, we are interested in the relative roles of volume diffusion and coupled dissolution-reprecipitation processes in mineral replacement.
I am a participant in four FP7 Marie Curie Initial Training Network (ITN) projects of the European Union:
Mineral Scale formation - from the nano to the field scale (MINSC). MINSC addresses the current and future challenges of mineral scale formation. The research themes of MINSC relate to the mechanisms of nucleation, growth and inhibition of mineral scale formation through experimental and field projects. Scale formation is a common and costly phenomenon in many industrial processes that deal with water or other fluid handling systems (i.e., wells, heat exchangers, tanks and delivery lines, etc.), where mineral precipitation in pipes, on equipment or as fracture filling has a detrimental effect on process efficiency, cost and lifetime of processing technologies. Scale formation is encountered in a large number of industries including paper-making, chemical manufacturing, cement operations, food processing, as well as non-renewable, (i.e., oil and gas) and renewable (i.e., geothermal) energy production. To learn more about MINSC see http://www.see.leeds.ac.uk/minsc/
Flow in Transforming Porous Media (FlowTrans). The characterization and the understanding of flow of fluids within rocks and granular media has become an ever-increasing problem in Earth Sciences, Physics, and in many industrial
applications, including CO2 sequestration, hydrocarbon migration, ore deposit development, and radioactive waste disposal. One of the main problems is the understanding of flows in transforming porous media (PM), where the rocks and fluid pathways evolve spatially and temporally, for example due to chemical interactions with the flow, or due to compaction of the solid matrix. The dynamic feedbacks between flow, destruction of permeability due to compaction or local precipitation, and creation of permeability due to dissolution, chemical reaction or fracturing, makes understanding of such complex systems a challenge. Such feedbacks between flow of fluids and PM in which they are flowing, are important in both relatively slowly deforming PM such as in naturally evolving reservoirs, and in rapidly evolving PM such as fluid-filled fault zones or soils experiencing earthquakes, rapidly flowing grain-fluid mixtures in debris flows, or industrial processes in petroleum production such as pyrolysis or hydrofracking. We propose to study the feedback mechanisms and their impact on the porous media through an interdisciplinary approach between Earth Scientists and Physicists. State of the art analytical and experimental methods will be used on natural systems and rock analogues, and will be complemented by multi-scale dynamical simulations, to develop new basic understanding and new
methods that can be directly used in industrial applications.
The fate and consequences of CO2 injection into the subsurface (CO2-REACT). The injection of CO2 into the subsurface leads to mineral-fluid reactions, including dissolution, adsorption, nucleation, precipitation, and solid-solution formation: This network will provide training through research in these areas related to optimizing CO2 storage efforts in the subsurface. Mineral-fluid
reactions are also central to a large number of other societal issues including assuring drinking water quality, safe storage of radioactive waste products, and minimizing pollutant transport. The ability to accurately predict reactions in these systems is of utmost importance for municipalities and for industry
in Europe today, but it relies on a detailed description of mineral-fluid reactions. The motivation for focusing CO2-REACT on fluid-rock reactions is that the most important chemical reactions in nature take place at these interfaces. These reactions control the composition of both the solid and the fluid. They define the quality of the natural environment and they determine processes of importance to industry and society in general. In the past, it has been impossible to study solid-fluid interfaces, which are only a few molecules thick, but new, state-of-the-art techniques now allow direct,
in-situ and time resolved observation of reactions at the atomic scale. When coupled with traditional, macroscopic observations, these powerful techniques allow access to a previously inaccessible world.
Mechanisms of Mineral Replacement Reactions Initial Training Network (Delta-MIN). The research themes of Delta-MIN relate to the mechanisms of mineral reequilibration (phase transformation) in the presence of a fluid phase and will be investigated in a wide range of minerals and rocks, under a range of chemical and physical conditions, using both natural and experimental samples. The principles of interface-coupled dissolution-reprecipitation will be applied to investigate the mechanisms of processes important in earth sciences and in industry, including metasomatic reactions in rocks, chemical weathering, mechanisms in CO2 sequestration, the aqueous durability of nuclear waste materials, remediation of contaminated water by mineral reaction, and the preservation of stone-based cultural heritage. The research methods bring together a range of complementary expertise, from field-related studies to nano-scale investigations of reaction interfaces using state-of-the-art high resolution analytical methods. The application of fundamental principles of mineral reequilibration to a wide range of applications, together with industrial involvement at all levels will ensure that the project provides a strong platform for training. For further information see: www.delta-min.com.
|Centrella, Stephen||Relationship between density, volume and mass transfer through a fluid phase during hydration reactions in the Bergen Arcs, Norway|
|Pedrosa, Elisabete Trindade||Porosity generation during mineral replacement reactions|
|Ruiz-Agudo, Cristina||A non-classical analysis of BaSO4 precipitation and the role of organic polyelectrolytes|
|King, Helen||Olivine reactivity: From the atomic to the macroscopic scale|
|Kasioptas, Argyrios||Hydrothermal replacement of calcium carbonate by apatite|
|Perdikouri, Christina||Investigation of the Mechanism and Kinetics of Growth and Replacement Processes of Calcium Carbonate|
|Janßen, Arne||Replacement processes in crystalline and non-crystalline materials: Case studies of experimental ilmenite and borosilicate glass leaching|
|Lammers, Lydia||Biomineralbildungen in Mikromassen-Kulturen humaner Stammzellen und in humanem Knorpelgewebe|
|Kowacz, Magdalena||The effect of additives on water structure and solute hydration: Consequences for crystal nucleation, growth and dissolution.|
|Pöml, Philipp Frederik||Investigations on the suitability of pyrochlore and zirconolite compounds as nuclear waste forms|
|Mutter, Andreas||The Bond-valence deficiency model: A new application to describe mineral surface reactions|
|Müller, Ingo||Influence of Cellulose Ethers on the Kinetics of Early Portland Cement Hydration|
|Sethmann, Ingo||Calcareous Biominerals and Their Formation: Nano-Cluster Crystal Growth through Mineral-Organic Interaction as a Principle of Biomineralisation|
|Pollok, Kilian||Crystal growth patterns in solid solution systems: Case studies on oscillatory zoning and mineral replacement reaction|
|John, Timm||Physical and chemical processes during the dehydration of subducting oceanic lithosphere: Reactive fluid flow under high-pressure conditions|
|Geisler-Wierwille, Thorsten||Applications of Raman Spectoscopy in Materials Research and Geosciences|