The research carried out in work packages (WPs) 2,3 and 4 constitute the technological core of the CHROMIC project, where innovative methods and processes to extract the target elements Cr, V, Nb and Mo from slags are developed and tested. As for the first stage of any research, all this happens in the labs, and it is compartmentalized in different activities focused on reaching different targets that, once pieced together, will form an end-to-end stream – from the raw material to the final product. To get there, the implemented processes must be tested as a whole and with larger quantities of materials in a production-like environment (upscaling and validation): this is what happens, in a nutshell, in WP5.
To get a more detailed picture of the stage of the project in which the research effort culminate, we talked to Frédérique Bouillot, research and development engineer with Orbix, a service provider company specialized in slag treatment for the steelworks and leader of WP5. What follows is an account of what Bouillot told us about the work that has been done at Orbix.
As mentioned, the aim of WP5 is to validate the identified metallurgical processes. That means testing the processes selected at lab scale with larger amounts of materials and bigger equipment, and performing all the steps of a process (flowsheet) one after the other, the stream coming out of a unit operation being the input of the next one. In CHROMIC this validation procedure takes place at “Technology Readiness Level” (TRL) 5: the Technology Readiness Level is a standard method to estimate the maturity of technologies and ranges from level 1 (defined as “Basic principles observed”) to level 9 (“Actual system proven in operational environment”); level 5 means the technology is “validated in relevant environment”. In WP5 the selected processes are tested on equipment that can be upscaled at industrial level.
To do so, Orbix received data from the WPs that studied separately each step of the process. WP2 gave information about the physical pre-treatment of the material; WP3 indicated how to proceed with the leaching step; and WP4 provided the relevant data for the recovery of the target elements from leachates. All CHROMIC partners are thus involved in WP5: BRGM for the preparation step; MEAM and FEhS for roasting; TUK for leaching; HZDR for metal recovery; VITO, FehS and Orbix itself for the valorization of the residual (metal-depleted) matrix. Moreover, Orbix shares information with the partners in charge of the assessment of the whole process (Arche and VITO – WP1), and with BFI, whose task is to calculate the parameters for the industrial scale. Importantly, the information collected and the general assessment performed in WP1 take into consideration not only the technical efficiency, but also the environmental and economic aspects involved in the process to validate.