Extended Data Fig. 3: XRD data analysis of 2 min Ar-melted, 2 min & 4 min (Ar-10%H2) reduced Ni-ore samples, peak shifts and lattice contraction.
From: Sustainable nickel enabled by hydrogen-based reduction
(a) Comparative display the XRD patterns of samples; 100% Ar-melted for 2 min, 2 min and 4 min reduced in Ar-10%H2. The patterns are predominantly dominated by Mg-silicate peaks (Mg2SiO4 & MgSiO3), constituting over 95 wt.% of the samples. For simplification purposes, smaller peaks corresponding to Ca-Al-Fe oxides/silicates are not highlighted. (b) Provides an enlarged view of two peaks framed in green in (a). It is evident that these peaks shift towards the right as we progress to more reduced samples. Although arbitrarily chosen, a similar shift is observed for all peaks corresponding to the forsterite structure. (c) Illustrates evidence of lattice contraction in the forsterite structure as we transition from the Ar-melted sample to the 4-min sample reduced in H2 plasma. Additionally, it can be observed that the crystal structure of the refined Mg1.8Fe0.2SiO4 structure in the Ar-melted sample is expanded compared to its ICSD crystal structure. This expansion suggests that Mg ions are replaced by Ni/Fe in amounts exceeding the stoichiometric proportion indicated in the chemical formula.
