000165021 001__ 165021
000165021 005__ 20251204150239.0
000165021 0247_ $$2doi$$a10.1021/acs.iecr.5c02714
000165021 0248_ $$2sideral$$a146584
000165021 037__ $$aART-2025-146584
000165021 041__ $$aeng
000165021 100__ $$aNandal, Neha
000165021 245__ $$aUnderstanding the Thermal Decomposition of Mg(NO3)2·6H2O and Its Role in Sustainable MgO and NOx Recovery
000165021 260__ $$c2025
000165021 5203_ $$aThe thermal decomposition of magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) to produce MgO and NOx gases is an important stage in closing the loop for the direct nickel process (a low environmental impact process capable of producing high-purity nickel and cobalt using laterite ores). Nitric acid is used for leaching the laterite minerals, while MgO is used for the precipitation of metal ions; therefore, recycling the MgO and nitric acid from the barren liquor, which is rich in hydrated forms of magnesium nitrate, enables this process to be sustainable as well as effective recycling of the sludge. However, this process demands an advanced understanding of the thermal decomposition mechanism of Mg(NO3)2·6H2O into MgO and NOx gases and key parameters that can control the thermal decomposition process, product optimization, and the reactivity of the MgO produced. This present work studied the thermal decomposition of Mg(NO3)2·6H2O at different heating rates using thermogravimetric analysis (TGA), TGA-infrared (TGA-IR), and in situ high-temperature X-ray diffraction (XRD), while the MgO produced using different conditions was characterized using XRD, SEM, N2–physisorption, XPS, and citric acid reactivity testing. The TGA, TGA-IR, and high-temperature in situ XRD results obtained indicate that thermal decomposition of Mg(NO3)2·6H2O to MgO follows a multistage process with multiple intermediate products formed. At lower heating rates, the multiple stages of decomposition were clearly observed without overlapping, while at higher heating rates, these stages started overlapping (5 versus 20 °C/min). Thermal decomposition temperatures and heating rates clearly demonstrated that surface area, porosity, and particle size of the MgO were modified. The results from the reactivity tests (for reaction between MgO and citric acid) using MgO produced using different heating rates and final reaction temperature showed that MgO produced at lower heating rates and lower final reaction temperature were observed to be reactive (ranges tested were 5–20 °C/min and 500–800 °C), and this was most likely due to these samples having higher surface area and pore volume.
000165021 540__ $$9info:eu-repo/semantics/closedAccess$$aAll rights reserved$$uhttp://www.europeana.eu/rights/rr-f/
000165021 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion
000165021 700__ $$aPeriasamy, Selvakannan
000165021 700__ $$aTardio, James
000165021 700__ $$aPownceby, Mark
000165021 700__ $$aWebster, Nathan
000165021 700__ $$aJones, Lathe
000165021 700__ $$aNilsson, Mikael
000165021 700__ $$aGrocott, Stephen
000165021 700__ $$aBhargava, Suresh
000165021 773__ $$g64, 43 (2025), 20450-20457$$pInd. eng. chem. res.$$tIndustrial and Engineering Chemistry Research$$x0888-5885
000165021 8564_ $$s8427867$$uhttps://zaguan.unizar.es/record/165021/files/texto_completo.pdf$$yVersión publicada
000165021 8564_ $$s3311901$$uhttps://zaguan.unizar.es/record/165021/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada
000165021 909CO $$ooai:zaguan.unizar.es:165021$$particulos$$pdriver
000165021 951__ $$a2025-12-04-14:39:29
000165021 980__ $$aARTICLE