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Length A novel pathway for the preparation of Mg metal from magnesia
No full textHigh-purity anhydrous magnesium chloride was prepared from magnesia and ammonium chloride. The chlorination process was analyzed and then the critical stages affecting the purity of anhydrous magnesium chloride were pinpointed. The effect of sample dimension on the above critical stages was investigated respectively. The purity guarantee mechanism of anhydrous magnesium chloride was proposed. After that, magnesium metal was obtained via electrolyzing the anhydrous magnesium chloride-containing molten salt. The new process for the continuous production of magnesium metal from magnesia was proposed and discussed. The incomplete chlorination reaction and the hydrolysis of anhydrous magnesium chloride are the two critical stages affecting the purity of the anhydrous magnesium chloride. The dimension of the sample can influence reaction process and reaction mechanism, and thus the problems of incomplete chlorination reaction and hydrolysis can be solved together. The magnesia content in anhydrous magnesium chloride was below 0.1 wt.% when the ratio of height to diameter of the sample was over 2.43. The content of impurities in the magnesium metal obtained met the specifications of the product Mg9980. The current efficiency was (94.7 +/- 1.8)% and the electricity consumption was (9107 +/- 97) kW h/t. (c) 2021 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Peer review under responsibility of Chongqing Universit
Leaching characteristics and solidification strategy of heavy metals in solid waste from natural graphite purification
No full textThe tailings and fluorine-containing sludge were produced during the physical and chemical purification of natural crystalline graphite, containing heavy metals in different occurrence forms. To evaluate the threat of different heavy metals to the environment, this work uses the modified sequential extraction method (BCR) to study the presence of heavy metals in two solid wastes and their dissolution characteristics in different environments. The results show that the pollution risk of heavy metals in graphite tailings to the environment is ranked as Mn > Cr > Ni > Zn, and the pollution risk of Mn in fluorine-containing sludge is higher than that of Cr. This is because the Mn in the two solid wastes mainly exists in the form of weak acid extraction. The leaching number of heavy metals in the two solid wastes is directly proportional to the soaking time and soaking temperature, and inversely proportional to the pH value and the solid-to-liquid ratio. The number of heavy metals dissolved in solid waste landfills is significantly higher than that of acid rain and surface water environments. Based on the above results and the distribution of graphite solid waste, solidification agent was suggested to prevent heavy metal dissolution and reduce environmental risks
Science and Technology Research Program of Chongqing Municipal Education Commission[KJQN201901334]
No full textResearch Foundation for Advanced Talents of Beijing Technology and Business University[QNJJ2022-22]
No full textMechanism and inhibition of abnormal chromatographic behavior of serotype type a inactivated foot and mouth disease virus in high-performance size-exclusion chromatography
No full textHigh-performance size-exclusion chromatography (HPSEC) has been developed for the rapid and quanti-tative analysis of inactivated foot and mouth disease virus (FMDV) and adopted by regulatory agencies and vaccine manufacturers. However, strong non-specific adsorption of type A/AKT III FMDV was found on some batches of TSK G40 0 0 SWXL column, which significantly affected the analysis accuracy. The ad-sorption mechanism was studied by investigating the charge and hydrophobicity of A/AKT III FMDV and another serotype O/Mya 98, as well as several model proteins, by zeta potential and hydrophobic inter-action chromatography analysis. Adsorption was related to both the FMDV strain and column lots. Some specific amino acids residues on the A/AKT III FMDV surface may strongly interact with the column if the silica-based stationary phase was not completely diol-modified. Several amino acids and chaotropic salts were screened as additives in the mobile phase to suppress the non-specific adsorption of AKT III FMDV in HPSEC analysis. Results showed that adding 0.4 M of arginine (Arg), lysine (Lys), NaClO4, or NaSCN achieved 100% FMDV recovery and normal retention time. Suppression of interaction between FMDV and the backbone of the silica matrix through competitive binding with residues of FMDV or the matrix is considered as the main mechanism by which these four additives act as suppressors. The addition of Arg, NaClO4, or NaSCN led to an apparent decrease in the thermal dissociation temperature Tm of FMDV, whereas Lys slightly increased viral stability. Finally, the mobile phase comprising 0.4 M Lys was screened as optimum that allowed accurate quantification of both two serotypes of FMDV according to method val-idation; particularly, a relative standard deviation (RSD) < 5% was achieved for AKT III FMDV using three different lots of columns. (c) 2022 Elsevier B.V. All rights reserved
