Development of ceramic grade red iron oxide pigment from waste iron source

Ceramic grade red iron oxide (α-Fe₂O₃) nanoparticles pigments have been synthesized from waste condensed milk containers which contain a prominent amount of iron (93.2%). The synthesis method comprised of two steps: in the first step ferrous sulfate was prepared following an acid leaching method; while the second step was oxidation and calcination of ferrous sulfate to produce desired α-Fe₂O₃ in nano form. The structure, functional groups, chemical state, morphology, particle size, surface area, elemental, thermal analysis and magnetic properties of the samples were investigated using XRD, FTIR, XPS, SEM, BET, EDS, TG-DT and VSM respectively. Pure hematite (α-Fe₂O₃) phase was confirmed by XRD and the average crystal sizes were in the range 34-126 nm have been performed by Debye-Scherer's formula, which are consistent with the results as achieved from SEM images. Agglomerated irregular spherical nanoparticles (45-149 nm) were found in SEM image. The surface chemistry and the chemical state (Fe³⁺) of the hematite nanoparticles was also confirmed by XPS. The mesoporous nature of the nanoparticles with high surface area were measured by BET and it has been revealed that the BET specific surface area (33.55 m²/g) was marginally higher than the commercial one. The magnetic nature of the nanoparticles was portrayed by VSM and the nanoparticles showed the ferromagnetic behavior. Moreover, particle size distributions and zeta potential values have been also measured by DLS.