Kinetics of leaching lithium from α-spodumene in enhanced acid treatment using HF/H_2SO_4 as medium

An enhanced leaching of Li fromα-spodumene was carried out using a mixture of hydrofluoric and sulfuric acid(HF/H2SO4)as the medium.Based on the optimized leaching conditions,the leaching kinetics of Li was investigated in an ore/HF/H2SO4 ratio of 1:3:2 g:mL:mL with leaching temperature ranging from 50 to 100°C.The results indicate that the leaching kinetics of Li fitted well with a model based on the shrinking core model.In addition,the leaching rate of Li was controlled by chemical reactions and diffusion through the product layers.The apparent activation energy Ea was calculated to be 32.68 kJ/mol.Solid films were formed because of the generation of insoluble products such as cryolithionite(Na3Li2Al2F12),cryolite(Na3AlF6),calcium fluoride(CaF2),potassium cryolite(K2AlF5),aluminum fluoride(AlF3),and fluorosilicates(Na2SiF6 or KNaSiF6).Furthermore,the effects of the ore/HF ratio and leaching temperature on the leaching behavior of Li,Al and Si were investigated.The results indicate that the ore/HF ratio and leaching temperature could clearly affect the distribution of HF molecules on the leaching of Li,Al and Si,which are important for the selective leaching of Li over Al and Si with this fluorine-based chemical method.

A novel apolipoprotein E mutation (p.Arg150Cys)in a Chinese patient with lipoprotein glomerulopathy

To the Editor:Lipoprotein glomerulopathy (LPG) is an uncommon inherited renal disease characterized by lipoprotein thrombi in the markedly dilated capillary lumina of affected glomeruli, high plasma concentrations of apolipoprotein E (apoE), and proteinuria.[1] It mainly affects people of Japanese and Chinese origin, and approximately 117 cases have been reported to date.[2,3] Several genetic studies have demonstrated that APOE gene mutations may lead to the development of LPG;[4,5,6] however, conflicting published evidence has found that some patients with APOE variants were unaffected.[7] Thus, further studies are needed to examine the role of APOE mutations in the pathogenesis of LPG.This study investigated a novel point mutation in the APOE gene in a family with one LPG patient and an asymptomatic carrier of the same APOE variant.