Detailed Microparticle Analyses Providing Process Relevant Chemical and Microtextural Insights into the Black Mass

Eramet uses a combination of physical and hydrometallurgical treatment to recycle lithium-ion batteries. Before hydrometallurgical processing, mechanical treatment is applied to recover the Black Mass which contains nickel, cobalt, manganese and lithium as valuable elements as well as graphite, solvent, plastics, aluminium and copper. To evaluate the suitability for hydrometallurgical recycling, it is essential to analyse the Black Mass chemically but also with respect to size, shape and composition of particles in the Black Mass. The Black Mass of various battery recyclers was investigated by using a combination of SEM/QEMSCAN® analyses. This specific QEMSCAN® database contains 260 subgroups, which comprise major and minor chemical variations of phases. The database was created using millions of point analyses. Major observations are: (1) particles can be micro-texturally characterised and classified with respect to chemical element contents; (2) important textural and chemical particle variations exist in the Black Mass from several origins leading to different levels of quality; (3) elements deleterious to hydrometallurgical processing (i.g. Si, Ca, Ti, Al, Cu and others) are present in well liberated particles; (4) components can be quantified and cathodes active material compositions (LCO, different NMC, NCA, LFP, etc.) that are specific for each battery type can be identified; (5) simulation of further physical mineral processing can optimise Black Mass purity in valuable elements

Detailed Microparticle Analyses Providing Process Relevant Chemical and Microtextural Insights into the Black Mass

Eramet uses a combination of physical and hydrometallurgical treatment to recycle lithium-ion batteries. Before hydrometallurgical processing, mechanical treatment is applied to recover the Black Mass which contains nickel, cobalt, manganese and lithium as valuable elements as well as graphite, solvent, plastics, aluminium and copper. To evaluate the suitability for hydrometallurgical recycling, it is essential to analyse the Black Mass chemically but also with respect to size, shape and composition of particles in the Black Mass. The Black Mass of various battery recyclers was investigated by using a combination of SEM/QEMSCAN® analyses. This specific QEMSCAN® database contains 260 subgroups, which comprise major and minor chemical variations of phases. The database was created using millions of point analyses. Major observations are: (1) particles can be micro-texturally characterised and classified with respect to chemical element contents; (2) important textural and chemical particle variations exist in the Black Mass from several origins leading to different levels of quality; (3) elements deleterious to hydrometallurgical processing (i.g. Si, Ca, Ti, Al, Cu and others) are present in well liberated particles; (4) components can be quantified and cathodes active material compositions (LCO, different NMC, NCA, LFP, etc.) that are specific for each battery type can be identified; (5) simulation of further physical mineral processing can optimise Black Mass purity in valuable elements

Influence of chemical composition on the microstructure and phase transformations of Fe-14Cr ferritic steels

International audienceThe effect of strengthened elements (Y2O3 and TiO2) on the microstructure has been investigated in Fe-14Cr-1W based ferritic steels. Titanium content and/or volume fraction of yttria range between ~ 0 up to 0.3 wt%.The volume fraction of nanoparticles is shown to control the grain size whereas titanium content has a significant influence on the chemical homogeneity. Martensite phase was obtained on a Fe-14Cr-1W based ferritic steel after consolidation by Hot Isostatic Pressing because of a higher content of carbon. A relationship between martensite phase and chemical heterogeneities was evidenced showing a chemical partitioning phenomenon. This phenomenon was also observed on ODS ferritic steels containing a low content of titanium (≤0.05 wt%) however microstructural parameters, such as size and volume fraction of nano-precipitates and grain size, are shown to delay the formation of martensite during cooling by decreasing the value of critical cooling rate.Thermodynamic calculations indicate that the minimal titanium content to get a microstructure with 100% of ferrite is about 0.09 wt%

Influence of oxide volume fraction on abnormal growth of nanostructured ferritic steels during non-isothermal treatments: An in situ study

International audienceNanostructured ferritic steels were mechanically alloyed with various contents of oxide-forming yttrium and titanium (0, 0.05, 0.3 and 1 wt%). The microstructure evolution of the milled powders during non-isothermal annealing treatments was studied using in situ synchrotron X-ray diffraction. Recrystallization and grain growth were quantified upon heating up to 1100 degrees C, which is the typical consolidation temperature for nanostructured ferritic steels. The temperature where abnormal grain growth occurs is observed to increase with the volume fraction of oxide nanoparticles. This demonstrates the interest of increasing the amount of alloying elements to limit the formation of the bi-modal grain microstructure. Using the nanoscale characterization of the precipitation state, the size of retained ultrafine grains (UFG) in the bimodal microstructure was found to be in agreement with the modified Zener theory demonstrating that the microstructure of ultrafine-grained steels can be tailored by the amount and size of second-phase particle