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The electrolytic manganese industry in a karst mountainous area in southwestern China is relatively developed. While producing electrolytic manganese, a large amount of manganese slag is also produced. The manganese slag is mainly treated by landfill storage, and there are more than 20 electrolytic manganese slag yards in the area. Manganese slag yards are mostly located in karst depression areas, and the groundwater environment is extremely fragile. There are 11 manganese slag inventories that are leaking and polluting the groundwater environment. In response to the specific problem of leakage from two electrolytic manganese slag reservoirs in the area, which pollutes the downstream karst underground river outlet, the goal is to improve the groundwater environment and save funds for sewage treatment. With the hydrogeological unit as the research scope, the research focuses on the groundwater pollution path and hydrogeological conditions, through investigation, sampling analysis, drilling, geophysical exploration, connectivity test, pumping test and other work methods. It has been identified that the leakage of two manganese slag reservoirs is the main cause of pollution at the outlet of the underground river. The slag reservoirs are suspended above the groundwater level, and pollutants in the slag body enter the groundwater through six channels. The manganese slag reservoir is located in the discharge area of the groundwater system, and the groundwater in the reservoir area and downstream has been polluted, accounting for 8. 33% of the underground river basin area. The recharge and runoff areas of the groundwater system are all karst depressions, and the groundwater is not polluted. There are three concentrated groundwater runoff zones. According to the characteristics of groundwater pollution and hydrogeological conditions in the study area, the idea of source prevention and control of "divisional treatment, separation of clean water and sewage" is proposed. The results of the pumping test show that after implementing the treatment project according to this treatment method, the overall water volume at the outlet of the polluted underground river can be reduced by more than 70%, saving 3 million ¥/a in sewage treatment funds. [ABSTRACT FROM AUTHOR]

Titaniumdioxide (TiO2) has been widely used as pigment in paints,fillers for plastic and paper, coatings, adsorbents, cosmetics, catalysts,and gas sensors. A novel process for TiO2production hasbeen developed by the Institute of Process Engineering. This workdevelops the novel process by using the NaOH/KOH binary molten salt(50 mol % NaOH, 50 mol % KOH) instead of NaOH molten salt. Under conditionsof temperature 350 °C and mixed alkali-to-titanium slag ratio1.4:1, the titanium conversion ratio obtained is >98% with reactiontime around 90 min. The kinetics investigation indicates that thedecomposition of titanium slag is controlled by mass diffusion inthed residual layer and the apparent activation energy is 43.1 kJ/mol.98% of KOH and 86% of NaOH can be recycled by a water leaching process.On the basis of the experimental results, a flow sheet was developedand tested, and the content of TiO2obtained in the productreached 99.5%. As the NaOH/KOH binary molten salt system providesa liquid as relatively low temperature, the energy consumption ofthis technology may probably be lower than that of the existing one. [ABSTRACT FROM AUTHOR]

TiO2 is a latent anode material for rechargeable lithium batteries. Our simulation models, basing lepidocrocite and λ-MnO2 type TiO2, were investigated by density functional theory (DFT). The key issues are focused on the lithium insertion sites, electronic structures, and the conducting paths of Li+ ions. Our calculated data indicate the calculated voltage of λ-MnO2 type TiO2 is higher than that of lepidocrocite type TiO2. The Li+ ion migration energy barrier of lepidocrocite type TiO2 along the [1 0 0] direction (0.45 eV) is lower than that of along the [1 1 0] direction (0.57 eV). The energy barriers of λ-MnO2 type TiO2 to move a Li+ ion among the adjacent embedded sites ( 16c or 8a sites) is 0.68 eV. [ABSTRACT FROM AUTHOR]

CaTiO3 was decomposed by alkaline roasting method for the production of TiO2. The process included alkaline roasting, water leaching and acid leaching steps. In the alkaline roasting step, the factors such as roasting temperature and NaOH/CaTiO3 molar ratio were investigated and 99.5% TiO2 could be extracted from CaTiO3. In addition, it is believed that only ion-exchange between Ca2+ and Na+ takes place, while the structure of TiO in CaTiO3 was not destroyed during the roasting process. In the acid leaching step, Ca(OH)2 could be completely leached at pH = 6−7 and Na2TiO3 was completely hydrolyzed simultaneously. The crystal structure of the leached sample seemed to be affected by pH and sequent calcination temperature. Finally, a flowsheet was proposed for the extraction of TiO2 from perovskite. [ABSTRACT FROM AUTHOR]

Abstract: Three mesoporous TiO2 samples were successfully synthesized by the modified evaporation induced self-assembly methods and hydrothermal process. All obtained mesoporous TiO2 samples only exhibit the anatase crystalline phase in theirs framework. The mesoporous TiO2 samples prepared by modified evaporation induced method show better mesostructure than that one prepared by hydrothermal process since the evaporation of ethanol and hydrolyzed butanol is conducive to the pre-organization between Ti-sources and surfactant micelles and then forming the stable inorganic–organic interface. The mesostructure appearance can distort the TiO6 octahedrons in the structure of anatase framework and cause the light absorbed peaks shifting to longer wavelengths. [Copyright &y& Elsevier]

Highly ordered MCM-48 was synthesized in the hydrothermal system of a mixture of cationic cetyltrimethylammonium bromide (CTAB) and nonionic poly(ethylene glycol) monooctylphenyl ether (Tx-100) using water glass as the silicon source. The effect of various factors, such as the amount of surfactant, CTAB/Tx-100, Si source, crystallization temperature, and crystallization time, on the synthesis were discussed in detail. The local effective surfactant packing parameter theory and the charge balance theory were used to explain the reason that various factors can affect the product structure reasonably. Especially, the role of Tx-100 was expounded. The optimum synthesis conditions for MCM-48 were obtained.