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


On 18th November 2019, the CHROMIC project was invited to present in the “Horizon 2020 Technology success stories” at the Raw Materials week (18-22 November 2019) in Brussels.



After a brief introduction on the overall CHROMIC concept, the talk (given by coordinator Liesbeth Horckmans) focused on the technological challenges and the importance of ensuring economic and environmental sustainability of the developed technologies. The key issues identified by the 1st iteration of the integrated assessment were discussed, and some examples were given of how these results were used to further improve the processes.


The full programme, presentations and photos are available for download at


On 22nd November 2019 CHROMIC joined a wide group of EU H2020 projects to host a satellite event of the EU Raw Materials Week on “Public Acceptance and Social Impact of Mining and Mineral Recycling in Europe”.

The workshop aimed at setting a debate and proposing recommendations on how to improve public acceptance of mining activities, in a society in which these are – though essential for a transition to a low-carbon economy – often confronted with a negative reputation.

The satellite event was hosted by the projects NEMO, CROCODILE, TARANTULA, SecREEts, INFACT and CHROMIC itself and gathered representatives from industry, government, NGO, local citizens group, academia and international institution, who shared their points of view and provided recommendations before engaging in a lively debate on the topic of social acceptance with the numerous attendees of the event.

A detailed account of what emerged from the discussion can be found on the NEMO website at this page:


On 22 and 23 November, the BRGM headquarters in Orléans, France, hosted the CHROMIC year 1 Project Meeting, during which the partners took stock of the first 12 months of the project and planned the next steps, focusing on the objectives for the second year.

The technical work packages which have already started (WP 2-3-4) discussed the very first scientific results. WP1 showed a detailed analysis focused on the EU regulations about slags, while WP6 updated the Consortium about the communication strategies and the preliminary results of the first community involvement activities.

The Annual Meeting was hosted in the BRGM headquarters in Orléans. BRGM (Bureau de recherces géologiques et minières) is the only French partner in the CHROMIC consortium and it is France’s reference public institution for Earth Science applications in the management of surface and subsurface resources and risks. The key objectives of its research are understanding geological processes and associated risk, developing new methodologies and techniques, producing and disseminating data to support the management of soils, subsoils and resources and delivering the necessary tools for the management of soils, subsoils and their resources, risk prevention and policy responses to climate change.

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