Metals Production, Refining and Recycling
Metals Production, Refining and Recycling” (MPRR) is a unique research group in process metallurgy and metallurgical recycling in the Netherlands. The group is responsible for all education and research within TU Delft related to metals extraction from primary and secondary resources. The group is active in scientific research covering both fundamental and application aspects in metals extraction and recycling through experimental studies and process modelling and simulation (thermodynamic/kinetic, CFD & DEM).
The MPRR group tries to “close the metals cycle”: starting from primary extraction and ending at the metals recycling. Our research focuses on the development of more efficient and sustainable technologies for metals extraction and recycling industry. The research of the group contributes to the sustainable production and supply of metals with minimum environmental impact. Greening the ironmaking and steelmaking with various de-carbonization innovations are, among others, our top priority now and in the near future.
We are active in scientific research covering both fundamental and applied aspects of materials recycling. We aim to support sustainable development and increase resource utilization by:
- Developing recycling routes for various materials, including battery electrodes, REEs from NdFeB magnets, eyewear frames, CFRPs
- Improving the recyclability of future products by looking into innovative approaches to make them more sustainable - design for recyclability
Research is conducted through a combination of metallurgical experiments (pyro- or hydrometallurgy, electrochemical) and process modelling (thermodynamic, kinetic, CFD, DEM).
Extractive metallurgy forms the most upstream disciplines in the life cycle of metals, connecting to the disciplines of metals science and technology within the Department MSE, and metals recycling forms the most downstream discipline regarding the metals supply chain. Our research focuses are subdivided into the following 2 fields: (1) efficient primary metals extraction and refining; (2) metals recovery and recycling; aiming for more efficient resource utilisation (minerals and energy) in metals production and recycling. The research of the group is conducted by a combination of metallurgical experiments and process modelling for both process fundamentals and industrial applications. The closely related industrial partners are Tata Steel, Nyrstar Budel Zinc, Van Gansewinkel Groep, Auto Recycling Nederland (ARN), to name a few. The group has dedicated research labs for Pyrometallurgy, Hydrometallurgy, Electrometallurgy (in aqueous solutions and molten salt electrolytes), and modern analytical and characterisation facilities, as well as modelling and computational tools (CFD, DEM, thermodynamics).
Internationally, MPRR is recognised as a small but dynamic research group covering wide areas of process metallurgy and metals recycling. The group has built a broad international cooperation network with well-known academic institutions in process metallurgy, e.g. KU Leuven (Belgium), Aalto University (Finland), NTNU (Norway). The group has also shown a good visibility through participation and presentation of research results in major international conferences in the field of process metallurgy. MPRR group is active in EU raw materials competence network and participating actively in EU Frame Work programs for research and development (MC-ITN EREAN, REEcover, MSP-REFRAM, SCRREEN). MPRR, representative of TU Delft, is a core partner of PROMETIA – Mineral Processing and Extractive Metallurgy for Mining and Recycling Innovation Association (www.prometia.eu), MPRR group is also an active player of TU Delft as core partner for KIC Raw Materials: “EIT Raw Materials”.
History of process metallurgy in the Netherlands
Education in mining and metallurgy in the Netherlands was one of oldest engineering braches given in Delft, when TU Delft received the status of Polytechnic School in 1864 and the “Technische Hogeschool', or an 'Institute of Technology" in 1905. Process metallurgy started around the year 1902 with Professor S.J. Vermaes (1902-1927) in the mining department of the Polytechnical School of Delft. The old mining building “Mijnbouw” of TU Delft at Mijnbouwstraat 120 was built in 1912 with more than 100 years history (it was returned back to the Municipality Delft in 2006). Delft remains as the only place for education in mining and metallurgy in the Netherlands.
The education in extractive metallurgy remained in the Department of mining and petroleum engineering (later Department of Applied Earth Science, and then Geo-technology) until 2005. The chairs in extractive metallurgy have been held by 9 professors: S.J. Vermaes (1902- 1927), M.H. Caron (1927 - 1951), J.E. de Graaf (1951-1975), H.J. Roorda (1962-1985), W.P.C. Duyvesteyn (1985 – 1989), G. van Weert (1990 – 1995), Ruurd Heerema (1986 – 2002), Udo Boin (2001 – 2004), and Markus Reuter (1996 – 2005). The well-known Caron Process for processing Nickel Laterite ores was invented by Prof. Caron in 1920, and first commercial plant (Freeport Sulfur Company) was in Nicaro (Cuba) in 1944, and 3 out of 5 plants worldwide are still in use.
In September 2005, the research team of Dr. Yongxiang Yang in extractive metallurgy from Department of Geotechnology (faculty CiTG) moved to the department of Materials Science and Engineering of the faculty 3mE, and a new group Metals Production, Refining and Recycling (MPRR) was formed with prof. Dr. Rob Boom (part-time), NIMR chair in process metallurgy. Prof. Boom worked at Corus Group (later Tata Steel Europe) as a R&D director in competence. The education in extractive metallurgy has been given since 2005 by the MPRR group in both the department of Geotechnology (faculty CiTG) and the department of Materials Science and Engineering (faculty 3mE). The research in metallurgy has been conducted exclusively by the MPRR group, in connection with supervision three levels of students: bachelor, master and PhD.
The Netherlands has quite strong metallurgical industry, with a total metals production of around 8 million tons at the present time. The existence and the continuation of education and research in process metallurgy in Delft has very close cooperation with the metallurgical industry: Ironmaking and steelmaking, zinc and aluminium production. Metallurgical industry provides valuable opportunities for training/internships, and study tours for our students and education, and supports the research projects in training PhD and postdoctoral education. Hoogovens started ironmaking and steelmaking in 1924, later became Corus and Tata Steel Europe, has been and is still the strategic partner of the metallurgy group. Budel Zinc, a primary zinc smelter, started zinc production in 1892, later became Budelco, Pasminco, Zinifex, now part of the Nyrstar group (the world largest primary zinc producer) has a close cooperation with our education and research in extractive metallurgy. Netherlands has also primary aluminium production through two smelters: Adel in Delfzijl Groningen (since 1966), and Picheney (later Alcan and Zalco) in Vlissingen (since 1971). The aluminium production in Vlissingen stopped in 2011, but remains in Delfzijl under the ownership of Klesch & Company Limited.
Our research is focused in the following fields, aiming for more efficient resource utilisation and cleaner production in metals extraction and recycling.
The research of the group is conducted mostly through a combination of metallurgical experiments and process modelling (thermodynamic, kinetic, CFD, DEM) for both process fundamentals and industrial applications.
- CHIRON: Towards a carbon-lean HIsarna ironmaking process - Influence of H2 enrichment, mineralogy and microstructure on smelting reduction of iron-bearing raw materials. (PhD, Tata Steel – M2i)
- Max-SCORE: Maximizing SCrap in COnverter REfinging - Shifting the limits of scrap usage in steelmaking converters to minimize CO2 emissions (PhD, Tata Steel – M2i)
- Interactions of circulating elements in the ironmaking blast furnace (PhD, Tata Steel – M2i)
- ReclaMet: Reclaiming valuable metals from process residues with the HIsarna process (1 PhD & 2 postdocs, EIT RawMaterials upscaling project)
- VALOMAG: Upscale of permanent magnet dismantling and recycling (postdoc, EIT RawMaterials upscaling project)
- HydroMetEC: Hydrometallurgy in raw materials utilization (EIT RawMaterials Lifelong learning project)
List of recent and ongoing projects
- Efficient and optimized sulphur removal in ironmaking and steelmaking (PhD, Tata Steel project)
- Shifting the limits for nut coke usage in ironmaking blast furnaces (2 PhDs, Tata Steel-M2i)
- Fundamental study of in-flight melting & reduction of iron ore particles in HIsarna new ironmaking cyclone reactor (PhD, postdoc, Tata Steel – M2i)
- EAERAN: European Rare Earth Magnet Recycling Network (2 PhDs, EU FP7 Marie Curie ITN project)
- REEcover: Recovery of Rare Earth Elements from magnetic waste in the WEEE recycling industry and tailings from the iron ore industry (2 PhDs, EU FP7 framework project).
- MSP-REFRAM: Multi-Stakeholder Platform for a Secure Supply of Refractory Metals in Europe (EU H2020 project)
- SCRREEN: Solution for Critical Raw Materials – a European Expert Network (EU H2020 project)
- RESTMETAL: Hydrometallurgical recovery of strategic metals from End-of-Life electronic wastes (1 postdoc, VGG – M2i project)
Research on extractive metallurgy and metals relying is multidisciplinary and thus, requires a variety of instruments and facilities. The MPPR group focuses on both the primary production of the metals and in recovering metals from various secondary resources and end-of-life waste. Our research focus can be broadly classified into the areas of hydrometallurgy and pyrometallurgy with two dedicated research labs. Our Hydrometallurgy lab has a range of facilities for leaching, solvent extraction, precipitation, electrowinning and electro-refining, and characterization of the finally produced metals. Our Pyrometallurgyl lab is equipped with arrange of furnaces that are specifically designed for ironmaking and steelmaking and molten salt electrolysis, and a thermal balance and a glove-box. The students also have access to XRD, XRF, ICP-OES, Ion Chromotograph, SEM/EDX, EPMA, and various optical microscopes.
The Hydrometallurgical Lab is equipped with a wide range of instruments and set-ups to cover different unit operations such as – leaching, solvent extraction, precipitation, and electrolysis (info_Yang_08.jpg). Starting with equipment required for mechanical activation like high energy ball mills, the lab contains a thermoshaker unit with accurate temperature control and multiple mixer - settler units that can be used for multi stage solvent extraction (info_Yang_09.jpg). Our group currently deals with variety of extraction processes such as recovering copper from WEEE in collaboration, recovery of REEs from mine tailings, recovery of REEs from WEEE, and decoating of NdFeB permanent magnet waste.
The Pyrometallurgy Laboratory deals with high-end research on primary production processes such as ironmaking as well as molten salt electrolysis. MPRR Pyrometallurgy Lab is recently completely re-built (info_Yang_10.jpg).
Our Reduction Softening and Melting (RSM) apparatus (info_Yang_11.jpg) is developed in house in collaboration with Tata Steel. It has the ability to simulate the real conditions (load, gas mixture and thermal profile) inside a blast furnace. It is used extensively for the projects dedicated to the process improvement and innovation in the domain of ferrous metallurgy. For effective ‘nut coke’ (size, 10-35 mm) utilization and for better understanding and control of circulating elements in the blast furnaces, RSM campaigns are actively in progress.
To study the in-flight behavior of individual solid particles in a high temperature atmosphere, high temperature drop-tube furnace (HTDF) was built to generate the solid – gas mixtures (info_Yang_12.jpg). It provides laminar flow conditions of gas – particle suspensions to avoid the particle – particle interactions. With controlled feeding of the solid particles, the high temperature behavior of the particles such as heating, reduction, gasification and melting can be investigated.
A recently developed macro-scale TGA furnace could be used for kinetic studies of larger sized samples, capable of monitoring the reaction processes at high temperatures up to 1600oC (info_Yang_13.jpg). The weight change together with off-gas analysis can be continuously measured and recorded onto computer system. To study the high temperature multi-phase reactions, high precision mass spectrometer (Hiden) can be connected to the off-gas system to continuously monitor the gas composition changes.
(macro-scale TGA furnace photo here: (info_Yang_13.jpg, to be taken)
Furthermore, our Pyrometallurgy lab is also equipped with a molten salt electrolyzer for study the production and refining of metals through high temperature electrolysis through molten melts.
Rare earth elements (REEs) are considered to be critical in EU due to fragilities in supply chain. MPRR group is an integral part of two different European collaborative consortiums (EREAN and REECover) which are aimed at recovering REEs from different end of life wastes.
Figure 1: The Hydrometallurgy lab
Figure 2: Leaching set-up (left) and a mixer-settler unit for solvent extraction (right)
Figure 3: The Hydrometallurgy lab: leaching fume cupboard
Figure 4: A two compartment electrochemical flow reactor for REE recovery from NdFeB waste.
In MPRR, special emphasis is provided to leaching and electrochemical processes. The hydrometallurgical lab is focussed on traditional processes such as electrowinning of copper from WEEE leaching and also on electro-refining of magnet waste. In addition to this, novel membrane based extraction processes are also currently investigated to recover critical metals. Electrochemical flow cells with ion exchange membranes offer unique possibility in metal recycling. One such two compartment reactor has been constructed and used to successfully demonstrate selective extraction of REEs from NdFeB waste at room temperature (Figure 4).
We have two different potentiostats (Versastat V4, PARSTAT 4000) that can be used separately or combined to form a bi-potentiostat. The units are capable of reaching ± 1A and ± 4A respectively with a compliance voltage of ± 10V and ± 48V. The PARSTAT 4000 can be attached to a power amplifier which is capable of reaching significant currents (± 20A). This is particularly relevant and sometimes essential to deal with high energy consuming processes such as REE metal production with molten salt electrolysis.
The Pyrometallurgy Laboratory deals with high-end research on primary production processes such as ironmaking as well as molten salt electrolysis. MPRR Pyrometallurgy Lab is recently completely re-built (Figure 5). Our Reduction Softening and Melting (RSM) apparatus (Figure 6) is developed in house in collaboration with Tata Steel. It has the ability to simulate the real conditions (load, gas mixture and thermal profile) inside a blast furnace. It is used extensively for the projects dedicated to the process improvement and innovation in the domain of ferrous metallurgy. For effective ‘nut coke’ (size, 10-35 mm) utilisation in the blast furnaces, RSM campaign is in progress. This project is sponsored by the m2i and Tata Steel. Besides variety of furnaces, the Pyrometallurgy Lab also contains a thermograviemetric analyser (TGA/DSC) and a glove box to store sensitive chemicals. To study the in-flight behavior of individual solid particles in a high temperature atmosphere, high temperature drop-tube furnace (HTDF) was built to generate the solid – gas mixtures. It provides laminar flow conditions of gas – particle suspensions to avoid the particle – particle interactions. With controlled feeding of the solid particles, the high temperature behavior of the particles such as heating, reduction, gasification and melting can be investigated.
Figure 5: The Pyrometallurgy lab (Left: furnace room; right: Glovebox and thermal analysis room)
Figure 6: Reduction - softening and melting apparatus (left) and the experimental set-up of the high temperature drop-tube furnace (right)
The Pyrometallurgy lab facilitates include:
- 1 vertical tube furnace (gas-tight, up to 1800 oC)
- 2 vertical tube furnace (gas-tight, up to 1600 oC)
- 1 horizon tube furnace (gas-tight, up to 1600 oC),
- 2 vertical tube furnace (gas-tight, up to 1200 oC)
- 1 vertical tube furnace (gas-tight, up to 1400 oC)
- 1 box furnace (up to 1500 oC)
- 1 box furnace (up to 1600 oC)
- 1 retort furnace (up to 1400°C)
- 1 drying muffle furnace
- 4 gas cleaning/pre-heating furnaces
- On-line gas analyser for 6 species (O2, CO, CO2, SO2, H2, H2O)
The pyrometallurgy lab and hydrometallurgy lab are associated with a range of analytical and preparation facilities, as is listed below:
- Glove box
- Thermal balance with dilatometry
- LECO analyses (C/S)
- Parstat 4000 with booster (up to 20 A)
- Versastat 4
- AAS analyses
In the department, we have full access to other characterisation facilities, workshop and sample preparation facilities.
- Polishing room
- Optical microscopy room