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A EU-funded project has pioneered new technologies, and new combinations of existing ones, to recover chromium and other metals from steelmaking by-products with high efficiency.


Chromium,vanadium, molybdenum and niobium: these four metals are crucial for the European industry. But they are almost exclusively mined and produced outside Europe – especially in China, Brazil, South Africa, Russia, Kazakhstan and Turkey – making the EU highly dependent on import. 

On the other hand, Europe has large quantities of those metals trapped in industrial by-products such as slags from steel, stainless steel and ferrochrome production. These slags are used mainly as aggregates in the construction industry, with small fractions even being landfilled. 

For four years, the partners in the CHROMIC project have worked to unlock the potential of these resources, in the end taking important steps towards the development of new sustainable ways of metal recovery and a near-zero-waste recycling of the entire slag- material. 

New technologies and smart combinations of existing ones have been developed and tested and applied to the three crucial steps of the recovery process: pre-treatment, selective leaching and selective metal recovery. A comprehensive study was undertaken to characterize the initial materials in more detail, prior to the recovery investigations.

The project succeeded in extracting over 95 % of chromium and lower amounts of the other three elements, using alkaline roasting with conventional or microwave heating  and water leaching (where the metal present in the solid mixture is dissolved into water). Heap leaching resulted in lower metal recovery, but might still have potential as lower cost and impact alternative for specific streams. 

The resulting solution (leachate) was treated by a combination of methods to separate valuable elements from impurities in the solution. The entire process reaches at least 85 % overall efficiency in recovering chromium. 

Ultimately, from the results of the tests performed during the technology validation stage, it was possible to estimate that (at least) 25000 tonnes of chromium per year can be recovered in Europe through the CHROMIC process. Potentially, thanks to CHROMIC, in the future the steel slags can be considered as metal deposits. 

However, a key remaining challenge is the valorisation of the treated matrix. The overall assessment performed in CHROMIC showed that this is a crucial factor for the economic and environmental sustainability of the process. Further optimization of the treatment tested in CHROMIC is needed to fully prevent the toxic form of chromium – Cr(VI) – leaching from the treated residue. The CHROMIC processes were shown to have potential in particular for waste streams that are currently landfilled due to Cr leaching. 

Beside technology-focused activities, CHROMIC also included an assessment of the impact of these technologies on the economy and – in a broad sense – on society. Through participatory events such as workshops and focus groups, CHROMIC collected the views and expectations of European citizens about the occupational, environmental and health aspects of metal production and recovery. The insight collected through the participatory events is meant to support researchers, the metal industry, EU policy makers and regulators in taking future decisions and steering further research, with the aim of increasing citizen’s awareness and gaining societal trust, hence preparing a path for successful market application of the system process and technologies introduced by CHROMIC. 

In all, the CHROMIC project has contributed to set the way towards the realization of a circular economy for critical raw materials, which has the potential to bring significant economic and environmental benefit to the European society.

Our project coordinator Liesbeth Horckmans (VITO) will be speaking at the 7th PROMETIA Scientific Seminar, which will take place online on 10th December, 9:00-16:30 CET. This year’s seminar will report on the raw materials community’s main results and challenges that remain to be addressed in the next Horizon Europe research and innovation programme.
Horckmans will present the CHROMIC project at 11.25 during the session titled “From waste to resources”.

For more information about the event and agenda, please visit


The final online conference of the CHROMIC project will take place as an online event on 19 November 2020 at 10 am.

This is the agenda:

10:00 – Welcome

Marcin Sadowsky (European Commission)

10:05 – Introduction – CHROMIC concept, goals and key results

Liesbeth Horckmans (VITO)

10:15 – Preparing the slags for further treatment through physical separation

Lena Kaipia (MEAM), Fero Kukurugya (VITO), Robert Moeckel (HZDR)

10:30 – Getting what we want, and only what we want: selective metal extraction from steel slags

Pavel Ivashechkin (BFI)

10:45 – Purification and up-concentration to metal products 

Norman Kelly (HZDR), Elena Seftel (VITO), Lubomir Pikna (TUK)

11:05 – Putting it all together – flowsheet integration and validation

Frederique Bouillot (Orbix)

11:20 – Is it worthwhile? Integrating economic, environmental and health and safety assessment 

Koen Oorts (ARCHE)

11:35 – Metals and the circular economy: what do the people think?  

Federica Manzoli (formicablu)

11:45 – Q & A 


We are pleased to invite you to the final online conference of the CHROMIC project, which will take place as an online event on 19 November 2020 at 10 am.

Creating a circular economy – where all resources are kept at the highest possible level of functionality and value at all times – is key to building a sustainable future, where innovation and economic growth can happen without further depleting the planet’s resources.

The CHROMIC research project – funded by the European Commission through the Horizon 2020 programme – aimed at creating building blocks of such an economy, focussing in particular on the metal industry. Over four years of work, It has investigated the selective recovery of  Chromium (Cr), Vanadium (V), Molybdenum (Mo) and Niobium (Nb) from metallurgical slags. These four metals are crucial for the competitiveness of the manufacturing sector and the innovation potential of high-tech sectors. Ensuring their steady supply is of strategic importance for the European industry.

During the conference, the CHROMIC partners will present the project results both at process and flowsheet level – from the preparation of the slags to their treatment, up to the purification of the final product and the valorisation of the residue.

These are all important first steps towards a true circular economy for the metals studied in CHROMIC, as well as for other critical raw materials.

The conference will also present the results of the economic, environmental and health & safety assessment of the processes studied and materials produced, as well as of participatory events (workshops and focus groups) that allowed CHROMIC to collect the views and expectations of European citizens about the occupational, environmental and health aspects of metal production and recovery. At the end, an interactive Q&A session will allow participants to share their perspective on the project.

Please register at this link:

in order to attend the conference.

Please feel free to forward this invitation to your colleagues and contacts.

We are looking forward to meeting you online – in the meantime do not hesitate to contact us if you need more information.


19 November 2020


Introduction – CHROMIC concept, goals and key results


Preparing the slags for further treatment through physical separation

This session will show how a combination of magnetic and density separation can up-concentrate Cr in an enriched fraction, while producing also metallic particles for direct reuse. Concentration of Cr is increased up to 3 times, while simultaneously reducing the amount of material to be leached.  


Getting what we want, and only what we want: selective metal extraction from steel slags

Selective alkaline leaching was chosen to extract metal from slags and make reuse of the residual matrix possible, avoiding the generation of large amounts of new waste streams. Different methods were evaluated, with traditional roasting allowing leaching rates of 100% for Cr and 33 % for V. Microwave roasting offers slightly lower rates, but is faster and more energy-efficient. 


Purification and up-concentration to metal products 

This session focusses on the separation and enrichment of the target elements from the leachates, and the transformation into final products. Two flowsheets will be presented: in one, with precipitation as a final step, a 99.99% removal of Cr with a purity of >99% was achieved. In the other, electrocoagulation resulted as a final step resulted in a complete removal of Cr.


Putting it all together – flowsheet integration and validation

The final step was to combine and upscale the best lab techniques identified in the three previous ones. Thanks to this process, from complex, low-grade waste streams, it could possible to recover more than 25,000 t Cr/year in Europe. Moreover, the residual matrix can still be carbonated for its valorisation as a construction material.


Is it worthwhile? Integrating economic, environmental and health and safety assessment 

Throughout the project, the economic, environmental and health and safety aspects of the processes studied and materials produced were assessed. When compared to current standard technologies, the economic viability and environmental friendliness of the integrated flowsheets strongly depends on the value of the starting material and the potential valorisation of the residual matrix materials.


Metals and the circular economy: what do the people think?   

Through three series of participatory events involving different stakeholders in four European countries, the CHROMIC project has gauged the level of knowledge, expectations and concerns of ordinary citizens, professional stakeholders and students when it comes to reinventing the metal value chain and orient it towards a circular economy. 



Interactive session – Q & A 

12:00 End of event


“How to define the impact of new technologies?” was the title of a workshop on Sustainability Assessment (SA) organized on the 21st of November 2019 in Brussels by NEMO in collaboration with CHROMIC, METGROW+ and NEW-MINE, as a Satellite Event to the 4th Raw Materials Week. Approximately 20 participants from academia, research, industry and government discussed the challenges and future of sustainability assessment in the field of raw materials and beyond. The present article reports on the key lessons learned from the presentations and lively debate, and looks forward to the next events in this clustering track.

In the Horizon 2020 calls for projects, consortia are explicitly asked to integrate a clear strategy on how to involve civil society, in order to build trust in the recovery, recycling and mining sectors in Europe. To meet these important requests, within CHROMIC a Community Involvement Plan (CIP from now on) was formulated. Aim of the plan is to share and discuss the technological, economic, societal and health-related aspects with stakeholders and local communities along the different phases of the project.

Some months ago, for the third podcast of our series, we interviewed the community involvement coordinator Federica Manzoli, who gave us an introduction to the CIP and told us about the – back then just concluded – first phase of it. Now, the work for the second phase has been carried on and we went back to Manzoli to ask her for an account of what was done and what came out of it. The following is a synthesis of what she told us.

The main difference between the two phases of the CIP is that the first was aimed at engaging with  laypeople, whereas the second was focused on involving the widest possible variety of stakeholders. Both were conducted in important industrial areas in four out of the five countries of the CHROMIC project partners. Like for the first phase, the second one’s events were held in Brescia (Italy), Leverkusen (Germany), and Lille (France), but this time Brussels was chosen instead of Genk in Belgium so that  representatives of the EU institutions could join. The four workshops took place between July and October and saw the participation of nearly fifty stakeholders.

The workshops were organized with the aim of raising the stakeholders’ interest in the CHROMIC project development and to consider the different points of view on the possible opportunities and problems that can emerge at the current and future stages of the project’s technological development. The meetings were tailored to focus on the assessment of the impacts of the project related to: Human health (e.g. noise production, hazardous substances causing respiratory effects); ecosystem quality (e.g. impact on water, soil, air); resources (e.g. land and water use, avoidance of further primary mining and production); climate change (e.g. greenhouse gases emission); economics. Within these “impact groups” a major goal was to understand what kind of scenarios CHROMIC can contribute to realize regarding, for example, the potential creation of local jobs, investments and profits.

The participants were chosen among stakeholders who locally count in decision making pertaining to the above mentioned fields: from local and regional health environmental agencies, to representatives of industries and industries associations, environmental associations and, in Brussels, representatives of the EU institutions. The wide and varied participation to the workshops – which in itself is a very positive result – produced fruitful discussions and valuable feedback.

Analysis of the outcomes of this round of events was finished a few weeks ago. Among the many points that have been brought to attention during the meetings, the impacts of CHROMIC and projects alike on land recovery and smart management of resources – especially to decrease dependence on primary raw material, reduction of pollution from detoxification of slags, and transportation logistics emerged as central issues to take into account for the development of the project.

Beyond that, a point to stress is that new technologies are regarded as successful only if they bring an economic advantage. All participants agreed that CHROMIC has the potential to bring so many benefits to a large number of areas, that if it is economically viable, it will be surely accepted and implemented by industries and also very welcomed by all other stakeholders.

“Events like the ones organized within the activities of societal involvement may help the diffusion of awareness among citizens” says Manzoli, “and regarding those participating in the workshops, we hope they will act as multipliers and help in disseminating better knowledge about the issues discussed”. On the other hand, the significance of setting up a dialogue with different categories of stakeholders for projects like CHROMIC was well explained in the Brussels’ workshop. In fact, one of the goals of this kind of event is to consider the cultural differences in the acceptance of new technologies and also the importance to spread quality information about the progress of the EU funded research. Technical issues, social issues, innovation issues, they require different experts, and this was the occasion to get them together.

What we learnt in the second phase of the CIP will be brought to the third and final phase, which will take place at the end of the project, in 2020. For that occasion, participatory events are planned, where local communities will be invited to discuss with researchers and other parties involved in the project, to discover the results and the scenarios opened by the CHROMIC technologies.

A year and a half has passed since the beginning of the project. Many tasks have been completed, many others are in process or scheduled to begin soon. This is an appropriate time to summarize what has been achieved so far within the project and what are the perspectives for the next future.

To do so, we have enlisted the help of the project coordinator Liesbeth Horckmans. The following is an account of what Liesbeth told us about the structure, the aims and above all the current status of the project.

Listen to the Episode 2 of the CHROMIC podcast 

The CHROMIC activities can be divided between those pertaining to the technological core of the project and those addressing assessments regarding the impact of the technologies on the economy and – in a broad sense – on society.

Starting with the technological core, this encompasses all the steps of the scientific work that will lead to the development of recovery processes for chromium, vanadium, molybdenum and niobium from slags, which is the primary aim of CHROMIC. These steps are grouped in dedicated work packages (WPs) and are: mineral processing (WP2), selective leaching (WP3) and selective metal recovery (WP4).

Mineral processing is about physical pre-treatment of the slags; in this WP pre-treatment and comminution techniques are applied to the slags in order to increase the concentration of the most interesting fractions. Then, in the leaching stage of WP3, hydro-metallurgical processes are applied to dissolve the metals of interest from their matrix and transform them to a leaching liquor, which is further treated in WP4 to recover the individual metals – or at least recover valuable products that can be put on the market.

The first sixteen months of CHROMIC have mainly been devoted to performing the physical pre-treatment techniques and leaching tests. The pre-treatment phase is almost coming to an end, as it is expected to be completed by the end of 2018. For the leaching, first trials have already been done and first concepts have been tested, but there will be room for improvement and optimization, as WP3 will be ongoing this and next year. Finally, metal recovery has started recently, in November 2017, so that part is – as expected – still at an initial stage.

Surrounding this technological core, the project includes supporting WPs such as WP1. One aim of this WP is to produce a value-chain analysis of the four metals of interest, to have an idea of where these metals are used today, what end-products they are and what are the boundary conditions for them. In the first sixteen months, a first version of the value chain assessments has been completed. However, this kind of research will continue throughout the project and will be updated based on the results of CHROMIC. Apart from that, WP1 also makes an integrated assessment of the technological developments, to make sure that they are in line with economic constraints, environmental considerations, societal wishes, legislations, and also importantly with health and safety aspects. In this respect, a first assessment round is in progress, meaning that a series of questionnaires have been sent to the project’s partners to gather initial data. That will allow early feedback to the research and development activities in WP2, 3 and 4, so that the technologies can be adapted to the needs and requirements of the aforementioned fields.

Other supporting activities are grouped in WP6, which consists of both communication and dissemination activities and – very importantly for CHROMIC – the community involvement. The aim is to get society to engage in the project, in order to have a good feeling of what potential objections might be raised in the future, and to make sure that the technological innovations produced will be accepted once they are on the market. A  first round of focus groups has been completed. These were attended by laypeople and gave an indication of what people’s mindset is toward recovery of metals, which is useful information to target the project’s further communication and to plan the next steps of the community involvement itself.

Finally – also as part of WP6 – clustering activities with similar European projects are being carried out. A monthly group with these projects has been established where Skype meetings regularly take place. Initially these meetings were focused on introducing the projects to each other and trying to find common grounds. The objective for this year is to work more on joint workshops, to have the possibility to cluster around some specific topics and share experience around designated questions such as community involvement and societal acceptance.

This project received funding from the European Union’s Horizon 2020 Research and Innovation program under Grant Agreement n° 730471

effiCient mineral processing and Hydrometallurgical RecOvery of by-product Metals from low-grade metal contaIning seCondary raw materials