Insights into lithium adsorption by coal-bearing strata kaolinite

The sharp increase in the demand for lithium(Li)for high-energy-storage battery materials due to its high specific energy and low negative chemical potential render Li a geopolitically significant resource.It is urgent to develop a low-cost,efficient method to improve lithium extraction.Herein,Li ion(Li+)adsorption in coal-bearing strata kaolinite(CSK)was studied.The effects of pre-activation acid leaching(meta-kaolinite/H2SO4,MK-HS)and dimethyl sulfoxide intercalation(coal-bearing strata kaolinite/dimethyl sulfoxide,CSK-DMSO)on the Li+adsorption capacity were studied under the same adsorption conditions.The results indicated that the adsorption was completed in 60 min under alkaline conditions(pH=8.5),a high solution concentration(400 mg/L),and a low dosage(1 g/100 mL);and the comprehensive adsorption capacity is MK-HS>CSK-DMSO>CSK.Furthermore,the DMSO intercalation caused the interlayer spacing of the CSK to increase,which provided more space for Li+to enter and increase the adsorption capacity.After thermal pre-activation and acid leaching,structural failure and lattice collapse resulted in the presence of more micropores in the MK-HS,which resulted in a 10-fold increase in its specific surface area and caused coordination bond changes(Al(VI)to Al(IV))and leaching of aluminum(Al)from the lattice.It is proposed that these structural changes greatly improve the activity of CSK so that Li+cannot only adsorb onto the surface and between the layers but can also enter the lattice defects,which results in the MK-HS having the best adsorption performance.Combined with the adsorption kinetics analysis,the adsorption methods of CSK and two modified materials include physical adsorption and chemical adsorption.In this study,the adsorption capacity of CSK and its modified products to Li were explored,providing a new option for the reuse of CSK and the extraction of Li.

Origin of Chromitites in the Songshugou Peridotite Massif,Qinling Orogen (Central China): Mineralogical and Geochemical Evidence

The Songshugou peridotite massif is located in the north of Shangdan suture zone, North Qinling orogenic belt of Central China. The massif is mainly composed of fine-grained mylonitic dunites, coarse-grained dunites, fine- and coarse-grained harzburgites, and minor clinopyroxenites. The coarsegrained dunites as well as parts of the harzburgites host small-scale chromitites? Chromite grains from various textural types of chromitites and dunites pervasively contain primary and secondary silicate inelusions. Primary inclusions are dominated by monophase olivine, with minor clinopyroxene and a few multiphase mineral assemblages consisting of olivine and clinopyroxene. Secondary inclusions, mainly Cr-chlorite and tremolite, show irregular crystal shapes. Besides, Cr2O3 contents (0.08 wt.%-0.71 wt.%) of primary olivine inclusions are remarkably higher than those of interstitial olivine (<0.1 wt.%). Chr0- mites in the Songshugou peridotite massif are high-Cr type, with Cr^# and Mg^# values ranging of 67.5-87.6, and 23.4-41.2, respectively. The Cr-chlorite, formed by reactions between olivine and chromite in the presence of fluid under middle temperature, indicates the Songshugou peridotite massif has undergone alteration/metamorphism process during emplacement. Chromite grains are modified by these processes, resulting in the various degrees of enrichment of Fe2O3, Cr2O3, Zn, Co and Mn, depletion of MgO, A12O3,Ga, Ti and Ni. Due to low silicate/chromite ratios in the massive ores, chromites from them are slightly influenced by alteration/metamorphism and thus preserve the pristine magmatic compositions. The parental magma calculated based on them has 11.17 wt.%-13.57 wt.% A12O3 and 0.15 wt.%-0.27 wt.% TiO2, which is similar to the parental melts of high-Cr chromitites from elsewhere and comparable with those of boninites. Combined with informations from previous studies, major and trace elements geochemistry of chromite, as well as the nature of the parental magma, it can be revealed that the Songshugou chromitities formed in a supra-subduction zone environment.