Theoretical Investigation of Thermodynamic Properties of the Al-Si-Fe Ternary Alloy.

Aiming at the current lack of thermodynamic parameters related to the preparation of aluminum-silicon-iron alloys from spent refractory materials in aluminum electrolytic cells, the Miedema model was used to calculate the thermodynamic parameters of Al-Si, Al-Fe, and Si-Fe binary alloys. On this basis, the Toop model was combined to calculate the mixing enthalpy ΔH, excess entropy SE, excess Gibbs free energy GE, and component activity α of Al-Si-Fe ternary alloys. The results show that ΔH, SE, and GE of binary alloys are all negative values. The properties of the Al element and Si element are similar, and they are different from the Fe element. The ternary alloys also have negative values of ΔH, SE, and GE in the alloy composition range, and their values change obviously in the region where the content of Fe is high or low. The activity values of all components decrease dramatically along with the diminishing of the corresponding molar fractions, and the activity values of Al, Si, and Fe are smaller in the central portion of the triangle of ternary components. It indicates that there is a strong interaction between the three elements, which easily forms ternary intermetallic compounds.

Effects of Coal-Fired Flue Gas Components on Mercury Removal by the Mechanochemical S-Modified Petroleum Coke.

In this work, the effects of coal-fired flue gas components (O2, CO2, SO2, and NO) on the Hg0 removal by the promising mercury removal adsorbent mechanochemical S-modified petroleum coke were characterized and analyzed in terms of the Hg0 removal efficiency, mercury adsorption capacity, and mercury mass balance. The results show that the mechanochemical S-modified petroleum coke with a theoretical sulfur content of 21% (named TSC-21) is the best candidate for mercury removal based on the Hg0 removal efficiency, Hg0 removal capacity, and difference ratio of Hg0 removal capacity (anti-interference ability) in the basic and full-component simulated flue gas atmosphere (N2 + O2 + CO2, N2 + O2 + CO2 + SO2 + NO). The maximum value (MV) and stable value (SV) of the Hg0 removal efficiency of TSC-21 in the basic simulated flue gas atmosphere are 99.25% (MV) and 91.17% (SV), respectively. O2, CO2, and NO all promote the Hg0 removal by the adsorbent, but they benefit the Hg0 oxidation while inhibiting the Hg0 adsorption. The promoting effect of O2 on the Hg0 removal by TSC-21 is affected by the reaction time, which is especially obvious after 1 min. The presence of SO2 inhibits the oxidation and adsorption of Hg0, which in turn reduces the Hg0 removal performance of the adsorbent. The improving effects on the oxidative escape of Hg0 by CO2 is higher than that by NO and O2. TSC-21 acts more as an oxidant than an adsorbent for Hg0 removal.

First-Principles Molecular Dynamics Simulation on High Silica Content Na3AlF6-Al2O3-SiO2 Molten Salt.

A new method for the disposal of the spent refractory materials by adding them directly to electrolytic cells requires our better knowledge of the Na3AlF6-Al2O3-SiO2 melt system. The development of computational materials science offers us a new way to avoid the limitation of the experiment under a strong corrosive environment at high temperatures. First-principles simulation is applied to study the structure information, electronic properties, and transport properties of the system. The study reveals that the main Si and Al ions in the melt are complex ion groups such as [SiF2O2]2-, [SiFO3]3-, [SiF3O2]3-, [AlF2O2]3-, [AlF3O]2-, and [AlF4O]3-. Tangled structures like [SiAlO3F5]4- also exist in the melt. The average coordination number of Al-F and Si-F is 3.21 and 2.45, respectively. O ions mainly act as bridge ions in the melt. The bonding ability of Al with O ions is stronger than that of Si with O ions. Moreover, the Al-O bond is mainly covalent, while the Al-F bond is basically ionic characters. The order of diffusion ability of ions from large to small is Na, F, Al, Si, and O. Addition of SiO2 into the Na3AlF6-Al2O3 molten salt causes an increase of the viscosity and a decrease of ionic conductivity.

Photosynthesis of the flag leaf blade and its sheath in high-yielding hybrid rice 'Liangyoupeijiu'.

Using high-yielding hybrid rice 'Liangyoupeijiu' (LYP9) and hybrid rice 'Shanyou 63' (SY63) as the experimental materials and using (14)C radio-autography, the photosynthetic capacities and distribution of photosynthates in flag leaf blades and sheaths of LYP9 were studied. The results showed that net photosynthetic rates (Pn) of the flag leaf blades and sheaths of LYP9 were much higher than those of SY63; the light transmissivity rates (LT) measured at the medium height of the flag leaf sheaths and the penultimate leaf sheaths were also significantly higher than those of SY63. The incipient activities, total activities and activation percentages of Rubisco in the flag leaf blade and sheath of LYP9 were all higher than those of SY63. The photosynthate transport rate in the sheaths of LYP9, and the quantity of photosynthate transported to the spikes and transformed to economic yield of LYP9 were all higher than those of SY63. The photosynthates produced by the sheaths were mainly transported to spike to make a certain contribution (about 15%) to yield.

[Phosphorus translocation and distribution in intercropping systems of soybean (Glycine max) and citrus (Citrus poonensis)].

A field mini-plot experiment was conducted on clay loamy oxisol using 32P trace technique when P fertilizer was applied in three depth soil (15, 35 and 55 cm soil layer) to compare P absorption, distribution and translocation in plant organ and soil profile under soybean and citrus monoculture and intercropping at Taoyuan Experimental Station of Agroecosystem Research of Chinese Academy of Science. Total P uptake (PT) and P accumulation in different parts (PA) of soybean were remarkably decreased under intercropping. When 32P was applied in topsoil (15 cm soil layer), 32P uptake (32PT) by soybean was significantly lower in intercropping than in monoculture. Whereas 32PT uptake by soybean was significantly greater in intercropping than in monoculture when 32P was applied in deep soil layer (35 cm or 55 cm soil layer). However, considerable difference was not observed for 32P translocation and distribution among soybean organs. 32PT uptake by citrus was much lower under intercropping than under monoculture. The P uptake by citrus newly could be transferred rapidly to aboveground and prior to active growing organ. Intercropping did not affect 32P distribution in citrus organ, but when P was applied in deep soil layer, the speed of 32P transferred to aboveground and active organ was slowed down. P mobility was strengthened in soil profile, and P of deep soil layer was promoted to move to topsoil in intercropping. The experimental results showed the optimal depth of applied P should be within 20 cm soil layer in soybean-citrus intercropping system.