Lead recovery from spent lead acid battery paste by hydrometallurgical conversion and thermal degradation.

Spent lead paste is the main component in lead-acid batteries reaching end of life. It contains about 55% lead sulphate and 35% lead dioxide, as well as minor amounts of lead oxide. It is necessary to recycle spent lead paste with minimal pollution and low energy consumption instead of the conventional smelting method. In this study, a novel approach involving hydrometallurgical desulphurisation and thermal degradation is developed to recover lead as PbO products from spent lead acid batteries. First, the desulphurisation effects and phase compositions of products with different transforming agents were compared, and the optimum conditions using (NH4)2CO3 as a transforming agent were determined. And then, the thermal degradation processes of both precursors lead carbonate and lead dioxide were investigated to prepare α-PbO, Pb3O4, and ß-PbO products in argon and air atmospheres, respectively. Both the desulphurisation precursors and the calcination products were characterised by thermogravimetry and differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy. The results showed that the lead oxide products were prepared, including α-PbO at 450°C in argon, Pb3O4 and ß-PbO at 480°C and 620°C in air, respectively.

Magnesia-stabilised zirconia solid electrolyte assisted electrochemical investigation of iron ions in a SiO2-CaO-MgO-Al2O3 molten slag at 1723 K.

Production of metallic iron through molten oxide electrolysis using inert electrodes is an alternative route for fast ironmaking without CO2 emissions. The fact that many inorganic oxides melt at ultrahigh temperatures (>1500 K) challenges conventional electro-analytical techniques used in aqueous, organic and molten salt electrolytes. However, in order to design a feasible and effective electrolytic process, it is necessary to best understand the electrochemical properties of iron ions in molten oxide electrolytes. In this work, a magnesia-stabilised zirconia (MSZ) tube with a closed end was used to construct an integrated three-electrode cell with a "MSZ|Pt|O2 (air)" assembly functioning as the solid electrolyte, the reference electrode and also the counter electrode. Electrochemical reduction of iron ions was systematically investigated on an iridium (Ir) wire working electrode in a SiO2-CaO-MgO-Al2O3 molten slag at 1723 K by cyclic voltammetry (CV), square wave voltammetry (SWV), chronopotentiometry (CP) and potentiostatic electrolysis (PE). The results show that the electroreduction of the Fe2+ ion to Fe on the Ir electrode in the molten slag follows a single two-electron transfer step, and the rate of the process is diffusion controlled. The peak current on the obtained CVs is proportional to the concentration of the Fe2+ ion in the molten slag and the square root of scan rate. The diffusion coefficient of Fe2+ ions in the molten slag containing 5 wt% FeO at 1723 K was derived to be (3.43 ± 0.06) × 10-6 cm2 s-1 from CP analysis. However, a couple of subsequent processes, i.e. alloy formation on the Ir electrode surface and interdiffusion, were found to affect the kinetics of iron deposition. An ECC mechanism is proposed to account for the CV observations. The findings from this work confirm that zirconia-based solid electrolytes can play an important role in electrochemical fundamental research in high temperature molten slag electrolytes.

Improved recovery of lithium from spent lithium-ion batteries by reduction roasting and NaHCO3 leaching.

Lithium supply risk is increasing and driving rapid progress in lithium recovery schemes from spent lithium-ion batteries (LIBs). In this study, a facile recycling process consisting mainly of reduction roasting and NaHCO3 leaching was adopted to improve lithium recovery. The Li of spent LiNixCoyMn1-x-yO2 powder were converted to Li2CO3 and LiAlO2 with the reduction effect of C and residual Al in the roasting process. NaHCO3 leaching was utilized to selectively dissolve lithium from Li2CO3 and water-insoluble LiAlO2. The activation energy of NaHCO3 leaching was 9.31 kJ∙mol-1 and the leaching of lithium was a diffusion control reaction. More than 95.19 % lithium was leached and recovered as a Li2CO3 product with a purity of 99.80 %. Thus, this approach provides a green path to selective recovery of lithium with good economics.

Liver kinase B1 correlates with prognosis and epithelial-mesenchymal transition of resectable early stage non-small cell lung cancer.

BACKGROUND: Recent evidences support that low expression of liver kinase B1 (LKB1) triggers epithelial-mesenchymal transition (EMT) through induction of Zinc finger E-box binding homeobox 1 (ZEB1) expression, which downregulates E-cadherin in human lung cancer cell lines. However, the clinicopathological significance of LKB1, EMT, salt-inducible kinase 1 (SIK1), ZEB1 and their relationship in early stage non-small cell lung cancer (ES-NSCLC) patients remain to be determined. In this study, the correlation among expression of LKB1, risk of distant metastasis, prognostic significance, and EMT in ES-NSCLC after surgery was investigated by immunohistochemistry. METHODS: Case notes and pathology records of 103 patients with ES-NSCLC were retrospectively analyzed. Immunohistochemical staining was employed to detect LKB1, EMT biomarkers (E-cadherin and vimentin), SIK1 and ZEB1 expression in ES-NSCLC tissues. RESULTS: LKB1 expression is associated with distant metastasis after treatment (P=0.017). LKB1-high expression group has better overall survival (OS) (P=0.000) and disease-free survival (DFS) (P=0.000). LKB1 expression is correlated with E-cadherin (r=0.231, P=0.019), vimentin (r=-0.225, P=0.022), SIK1 (r=0.218, P=0.027) and ZEB1 (r=-0.242, P=0.014). CONCLUSIONS: Our findings suggest that LKB1-high expression is possibly associated with favourable prognosis and LKB1 expression is correlated with EMT and expression of SIK1 and ZEB1.