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Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.

Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.

Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.

Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.

Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.

Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.

Ilmenite is the primary feedstock for the manufacturing of titanium goods, however it needs to be refined before the usage. Becher is an eco-friendly process for refining ilmenite by rusting metallic iron from reduced ilmenite to separate iron and TiO2, and NH4Cl is the commonly utilized solvent in this method. In the current study, the contribution of NH4Cl was investigated by comparative analysis of the rusting leaching behavior of iron in the Becher process environment, and the solvents including NH4Cl, CH3COONH4, NaCl and CH3COONa were selected. Electrochemical measurements including potentiodynamic polarization analysis, electrochemical impedance spectroscopy as well as surface morphology analysis utilizing scanning electron microscopy and atomic force microscopy were performed. The obtained results indicate that NH4Cl has the highest rusting rate, with NH3 playing the most important role than Cl-. The presence of ammonia prevents the formation of an oxide film on the iron surface. The DFT calculation reveals the NH3 adsorption on the Fe surface enhances Fe susceptibility to electron loss, consistent with the experimental observation of NH3-accelerated iron corrosion. The obtained understanding and methodology sheds lights on the mechanism of NH4Cl action and offers new insights for the study of rusting leaching catalysts., QC 20231017

Highly time-resolved measurements of water soluble ions, organic and elemental carbon concentrations in the particle diameter size range D-p <2.5 mu m (PM2.5) were performed at a downwind urban site in Nanjing in the western part of the Yangtze River Delta (YRD) in eastern China during the 2014 Youth Olympic Games (YOG). In this study, we discuss the impacts of emission control in Nanjing and the surrounding areas during the YOG and regional/long-range transport on PM2.5 pollution in Nanjing. The average concentrations of NO3-, SO42-, NH4+ were 12.1 +/- 9.9, 16.5 +/- 9.2, 9.0 +/- 5.4 mu g m(-3) during the YOG, and increased 34.3%, 53.7%, 43.9% after the YOG, respectively. The control of construction or on-road soil dust and control of industry led to the decrease of Ca2+ concentration by 55% and SO2 concentration by 46%. However, SO42- concentrations remained at relatively high levels, suggesting a significant impact of regional pollution to secondary fine particles in Nanjing. Strong correlations between OC and EC were observed during and after the YOG. A higher percentage (41%) of secondary organic carbon in Nanjing during the YOG periods was consistent with high potential photochemistry and low contributions from coal combustion. Lagrangian dispersion modelling results proved that the city clusters along the Nanjing and Shanghai axis were the major source region for high PM2.5 pollution in upwind Nanjing. This work shows that short-term strict control measures could improve the air quality, especially that affected by the primary pollutants; however, regional collaborative control strategy across administrative borders in the YRD is needed for a substantial improvement of air quality.

Debris flows in the mountainous regions south west of Beijing, China occur frequently and often result in considerable mass movements with disastrous consequences for human life, infrastructure and agriculture. Obtaining chronological information on such events is important for the prediction of the return frequency of these debris flows, risk assessment and climate change research. In this project, we use quartz single-grain optically stimulated luminescence (OSL) methods to determine the burial ages of five debris flow samples from the Zhai Tang region -60 km west of Beijing. OSL characteristics were found to be acceptable despite the low inherent brightness of quartz extracted from these samples. Single-grain thermal transfer was determined to be negligible and beta dose recovery experiments were satisfactory. The quartz single-grain dose distributions strongly indicate that the samples were poorly bleached prior to deposition; relative over-dispersions are larger than 60%. Minimum age modelling indicates that all five samples were deposited within the past few hundred years, indicating that catastrophic debris flows are occurring under the historically-recent land-use pattern.

Extreme seasonal summer rain storms are common in the mountains to the north east of Beijing and these often result in mass movement of sediment slurries transported for up to a few km. These debris flows can be deadly and are very destructive to infrastructure and agriculture. This project tests the application of luminescence dating to determining the return frequency of such extreme events. The high sediment concentration and the very short flow duration gives very little opportunity for daylight resetting during transport and only a small fraction of the total mass is likely to be reset before transport begins. Here we examine the quartz single-grain dose distribution from a recent known-age (<25 years) debris flow from a small (~3.9 km2) catchment ~140 km north of Beijing and compare it with those from three samples from a sedimentary sequence containing the evidence of multiple flow events. Multi-grain quartz OSL signals are dominated by the fast component and <1% of the 150e200 mm grains give a detectable test dose (4.5 Gy) response. Single-grain beta dose recovery gave a ratio of 0.97 ± 0.06 (n ¼ 30) with an over-dispersion of 23 ± 8% (CAM). Both the recent known age and the palaeo-distributions are highly dispersed with over-dispersions greater than 50%. The average weighted doses range between ~3 mGy and ~6.5 Gy, indicating that all deposits are no more than a few thousand years. Minimum age modelling give an age estimate for the youngest sample consistent with the known age, and minimum ages for the older palaeo-deposits suggest that there have been at least 3 major debris flows in this small catchment in the last 1000 years. © 2015 Published by Elsevier B.V.

Increasing alumina production in China and improvements in production technology have resulted in the depletion of high-quality bauxite resources. A calcification-carbonation method is described for the treatment of middle- to low-grade bauxite and red mud. Experiments using synthetic mixtures of pure NaOH, Al(OH)3, CaO and Na2SiO3 indicated that sodium aluminosilicate hydrate was transformed into hydrogarnet with increasing additions of CaO, but the alumina-silica ratio increased and the sodium-silica ratio decreased. The hydrogarnet was decomposed with CO2 at 120 degrees C at a CO2 partial pressure of 1.2 MPa. The alumina extraction efficiency was up to 63.6% and the alumina-silica ratio of the final product was reduced to 0.54. Treatment of diasporic bauxite, gibbsite and red mud under conditions of a calcification temperature of 240 degrees C for diasporic bauxite or 180 degrees C for gibbsite and red mud, a calcium oxide/silica molar ratio of 3:0.64, a carbonation temperature of 120 degrees C, and CO2 pressure of 1.2MPa reduced the alumina/silica ratios of the final products to 0.44, 0.82 and 0.43, respectively, and the sodium oxide contents to 0.12%, 0.57% and 0.44%. The final red mud product was suitable for direct use in the cement industry., Increasing alumina production in China and improvements in production technology have resulted in the depletion of high-quality bauxite resources. A calcification-carbonation method is described for the treatment of middle- to low-grade bauxite and red mud. Experiments using synthetic mixtures of pure NaOH, Al(OH)3, CaO and Na2SiO3 indicated that sodium aluminosilicate hydrate was transformed into hydrogarnet with increasing additions of CaO, but the alumina-silica ratio increased and the sodium-silica ratio decreased. The hydrogarnet was decomposed with CO2 at 120 degrees C at a CO2 partial pressure of 1.2 MPa. The alumina extraction efficiency was up to 63.6% and the alumina-silica ratio of the final product was reduced to 0.54. Treatment of diasporic bauxite, gibbsite and red mud under conditions of a calcification temperature of 240 degrees C for diasporic bauxite or 180 degrees C for gibbsite and red mud, a calcium oxide/silica molar ratio of 3:0.64, a carbonation temperature of 120 degrees C, and CO2 pressure of 1.2MPa reduced the alumina/silica ratios of the final products to 0.44, 0.82 and 0.43, respectively, and the sodium oxide contents to 0.12%, 0.57% and 0.44%. The final red mud product was suitable for direct use in the cement industry.

A method is proposed for dealing with by-product magnesium chloride resulting from the production of titanium sponge in the Kroll process. If Cl is to be circulated to titanium smelting and Mg to magnesium metal by way of aluminothermic or silicothermic reduction, the pyrolysis of MgCl2 must first be understood and its dynamics investigated. Experiments were carried out on anhydrous MgCl2 to determine the effects of temperature, time, oxygen partial pressure and gas flow rate on the efficiency of molten MgCl2 pyrolysis in a tubular furnace., A method is proposed for dealing with by-product magnesium chloride resulting from the production of titanium sponge in the Kroll process. If Cl is to be circulated to titanium smelting and Mg to magnesium metal by way of aluminothermic or silicothermic reduction, the pyrolysis of MgCl2 must first be understood and its dynamics investigated. Experiments were carried out on anhydrous MgCl2 to determine the effects of temperature, time, oxygen partial pressure and gas flow rate on the efficiency of molten MgCl2 pyrolysis in a tubular furnace.

A calcification-carbonation method has been proposed to change the equilibrium phase of red mud to 2CaO.SiO2 and CaCO3 hydrometallurgically, so that alkali-free red mud can be widely used in construction materials. Experiments on diasporic bauxite from Wenshan, China, were conducted to investigate the effects of grain size, temperature and treatment time on the digestion rate or calcification transformation rate. It was found that the main phase in the calcification slag is hydrogarnet with differing grain sizes and that the transformation rate increases with decreased bauxite grain size or increased temperature or time, reaching a maximum of 87% after 120 mins. reaction at 240 degrees C. The Na2O/Al2O3 ratio decreases to 1.5 with increased temperature, the Na content decreasing with reaction time to 4-12%, lower than that in Bayer process red mud., A calcification-carbonation method has been proposed to change the equilibrium phase of red mud to 2CaO.SiO2 and CaCO3 hydrometallurgically, so that alkali-free red mud can be widely used in construction materials. Experiments on diasporic bauxite from Wenshan, China, were conducted to investigate the effects of grain size, temperature and treatment time on the digestion rate or calcification transformation rate. It was found that the main phase in the calcification slag is hydrogarnet with differing grain sizes and that the transformation rate increases with decreased bauxite grain size or increased temperature or time, reaching a maximum of 87% after 120 mins. reaction at 240 degrees C. The Na2O/Al2O3 ratio decreases to 1.5 with increased temperature, the Na content decreasing with reaction time to 4-12%, lower than that in Bayer process red mud.

A calcification-carbonation method for changing the equilibrium structure of red mud produced from the Bayer process is described. The thermodynamics of both the calcification and the carbonation processes and the non-isothermal kinetics involved in the calcification process are analysed. The effects of calcification temperature and lime addition on the hydrogarnet synthesis process and of carbonation temperature and carbon dioxide partial pressure on the decomposition efficiency of the calcified slag are investigated using pure reagents. The results show that, using a two-step carbonation treatment of calcified slag, the alumina-silica mass ratio of the red mud structure is lowered to 0.44 and the sodium oxide content drops to 0.12 wt% at a carbonation temperature of 120 degrees C and a CO2 partial pressure of 1.2 MPa. The modified red mud is found to have direct applicability to the cement industry., A calcification-carbonation method for changing the equilibrium structure of red mud produced from the Bayer process is described. The thermodynamics of both the calcification and the carbonation processes and the non-isothermal kinetics involved in the calcification process are analysed. The effects of calcification temperature and lime addition on the hydrogarnet synthesis process and of carbonation temperature and carbon dioxide partial pressure on the decomposition efficiency of the calcified slag are investigated using pure reagents. The results show that, using a two-step carbonation treatment of calcified slag, the alumina-silica mass ratio of the red mud structure is lowered to 0.44 and the sodium oxide content drops to 0.12 wt% at a carbonation temperature of 120 degrees C and a CO2 partial pressure of 1.2 MPa. The modified red mud is found to have direct applicability to the cement industry.