@article{han_sagzhanov_pan_hassas_rezaee_akbari_mensah-biney_2022, title={Direct Extraction of Lithium from alpha-Spodumene by Salt Roasting-Leaching Process}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.2c04402}, abstractNote={In recent years, several methods have been reported to extract lithium (Li) from spodumene. However, the majority of them still require the transformation of the naturally occurring spodumene phase (α) to the more reactive crystalline phase (β) by calcination at 1100 °C. To address the economic drawbacks and high greenhouse gas emission of this phase transformation, this study aimed to directly extract Li from α-spodumene. Nine reagents of alkali metals (Group IA), alkaline earth metals (Group IIA), and ammonium (NH4+) salts were examined for roasting and phase transformation of α-spodumene to water- or acid-soluble phases. For this purpose, sequential roasting, water leaching, and acid leaching were performed. The leaching recovery results showed that the order of roasting efficacy of the three reagent categories is Group IA > Group IIA > > NH4+. 71 and 88% of water leaching and total leaching recovery values, correspondingly, were achieved by the NaOH roasting–water leaching–acid leaching process, under the nonoptimized conditions of a roasting temperature of 320 °C, an NaOH: spodumene ratio of 1.5:1, and a roasting time of 2 h. Thermodynamics analysis by FactSage demonstrated that α-spodumene was decomposed to Na2SiO3, Na4SiO4, NaAlO2, and Li3NaSiO4 by NaOH and to NaAlSiO4, Na2SiO3, and Li3NaSiO4 by Na2CO3. Eh-pH diagrams calculated by HSC Chemistry revealed that despite the low solubility of lithium silicates in water, they dissolve at high pH (>12.5), explaining the high water leaching recovery of Li. In future studies, the optimization of the process parameters will be conducted to maximize the Li recovery in water leaching, while recovering other valuable elements as byproducts.}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Han, Shihua and Sagzhanov, Daulet and Pan, Jinhe and Hassas, Behzad Vaziri and Rezaee, Mohammad and Akbari, Hamid and Mensah-Biney, Robert}, year={2022}, month={Sep} }
 @article{rezaee_han_sagzhanov_hassas_slawecki_agrawal_akbari_mensah-biney_2022, title={Microwave-assisted calcination of spodumene for efficient, low-cost and environmentally friendly extraction of lithium}, volume={397}, ISSN={["1873-328X"]}, DOI={10.1016/j.powtec.2021.11.036}, abstractNote={To utilize the advantages of microwave-assisted calcination over conventional heating, this work studied the effect of microwave power on phase transformation and leachability of spodumene. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized to characterize the phase transformation and structural changes of spodumene calcined by both microwave and conventional heating methods. Results showed that the effect of microwave power on both phase transformation and leachability of spodumene is significant. The optimum lithium recovery through the microwave calcination-acid roasting-leaching process reached 97% at 2.0 kW microwave power, comparable with that of conventional heating. Besides a more rapid, less energy-consuming, and free greenhouse-gas-emission calcination, microwave heating also resulted in lower recovery values of Fe, Na, and Ca in the leaching process, gaining an advantage in downstream purification processes. The microwave temperature profiles of spodumene, and characterization results confirmed that α-spodumene started to transfer into γ- and β-spodumene at around 900 °C.}, journal={POWDER TECHNOLOGY}, author={Rezaee, Mohammad and Han, Shihua and Sagzhanov, Daulet and Hassas, Behzad Vaziri and Slawecki, Tania M. and Agrawal, Dinesh and Akbari, Hamid and Mensah-Biney, Robert}, year={2022}, month={Jan} }