The Conversion of Calcium-Containing Phases and Their Separation with NaCl in Molten Salt Chlorinated Slags at High Temperature

The titanium resources in Panxi reign, China, have a high-impurities content of Ca and Mg, which is usually processed by the molten salt chlorination process. This process allows higher Ca and Mg content in its furnace burdens. However, there is a huge amount of molten salt chlorinated slag produced by this process, consisting of complex compounds and waste NaCl/KCl salts. These slags are always stockpiled without efficient utilization, causing serious environmental pollutions. To recycle the NaCl in the slag back to the molten salt chlorination process, a novel process to deal with those molten salt chlorinated slags with phase conversion at high temperature is presented in this paper. The calcium-containing solid phase was generated when Na2SiO3 was added to the molten salt chlorinated slags at high temperature, while NaCl was kept as a liquid. Thus, liquid NaCl was easily separated from the calcium-containing solid phase, and it could be reused in the molten salt chlorination process. The conversion of calcium-containing phases and their separation of NaCl are the key parts of this work, and they have been systematically studied in this paper; thermodynamic analysis, phase transformation behavior, and calcium removal behavior have all been investigated. The calcium removal rate is 78.69% when the molar ratio of CaCl2:Na2SiO3 is 1:1.5 at 1173 K and N2 atmosphere.

Aluminum surface nitriding by an atmospheric-pressure non-thermal plasma technique

The application of aluminum is often limited by low hardness, and plasma nitriding can make it have excellent mechanical property. The purpose of this study is to nitride the aluminum surface by non-thermal transferred arc plasma technology. During the plasma nitriding process, the maximum effective value of output current is about 390 mA and the overall temperature of the samples is much lower than the solidus temperature. It is found that the microstructure and mechanical properties of the aluminum surface are improved by adding hydrogen into the nitrogen plasma. Compared with the surface treated by pure N2 plasma, the particle size of aluminum surface treated by N2/H2 plasma is smaller. The surface hardness of aluminum is nearly doubled after being treated in 6.0 vol%H2 + 94.0 vol%N2 atmosphere.

Chlorine Release from Co-Pyrolysis of Corn Straw and Lignite in Nitrogen and Oxidative Pyrolysis

Elevated emissions of hydrogen chloride (HCl) from the combustion of biomass in utility boilers are a major issue because they can cause corrosion problems and deposit molten alkali chloride salts on boilers’ water tubes, resulting in further corrosion. Pyrolysis is a good pre-treatment for solving this problem. This work conducted pyrolysis and co-pyrolysis of pulverized corn straw and lignite coal in a horizontal muffle furnace, with compositions typical of power plant combustion effluents (5% O2, 15% CO2, 80% N2) at different temperatures. Cl compounds were monitored in fuel, flue gas, and solid production of pyrolysis. The co-pyrolysis significantly affected Cl release from fuel. Cl release from corn straw into fuel gas was reduced during biomass co-pyrolysis with lignite. Co-pyrolysis had little influence on the release of organic Cl and KCl. Furthermore, at moderate-temperature pyrolysis, O2 promoted HCl release, when compared with pyrolysis under a N2 atmosphere.

Flexible synthesis of high-performance electrode materials of N-doped carbon coating MnO nanowires for supercapacitors

The MnO/C composites were obtained by co-precipitation method, which used Mn3O4 nanomaterials as precursors and dopamine solution after ultrasonic mixing and calcination under N2 atmosphere at different temperatures. By studying the difference of MnO/C nanomaterials formed at different temperatures, it was found that with the increase of calcination temperature, the materials appear obvious agglomeration. The optimal calcination temperature is 400 °C, and the resulting MnO/C is a uniformly dispersed slender nanowire structure. The specific capacitance of MnO/C nanowires can reach 356 F g-1 at 1 A g-1. In the meantime, the initial capacitance of MnO/C nanowires remains 106% after 5000 cycles. Moreover, the asymmetric supercapacitor (ASC) was installed, which displays a tremendous energy density of 30.944 Wh kg-1 along with a high power density of 10 kW kg-1. The composite material reveals a promising prospect in the application of supercapacitors.

The Application of Thermal Decomposition for Determination of Carbonate Acid-Neutralising Capacity for Improved Acid Mine Drainage Prediction

This study developed an industry-applicable, thermal decomposition methodology for quantification of carbonate mineral acid neutralisation capacity (ANCtherm-carb) for waste rock, tailings, and other mined materials. Standard titration-based methods for ANC can be compromised due to contributions from silicate minerals, ion exchange, Fe-rich carbonates, and other transition metal carbonates. C emission (CO2 and CO) was measured using IR in a N2 atmosphere. Cneut (wt%) was calculated using the C emission at 800 or 1000 °C minus the C emission at 400, 450 or 500 °C and the weight of sample prior to decomposition (Equation (2) of this manuscript). This value was then input into Equation (3) of this manuscript to calculate ANCtherm-carb. Good correlation of ANCtherm-carb for single-mineral carbonates with ANCcalc, calculated from bulk assay concentrations for Mg, K, Na, Ca, and Mn, was achieved. Thereafter, 18 waste rock samples were examined, resulting in the correlation of ANCtherm-carb versus non-standard ANCtitrate-carb (titration methodology adapted to focus on carbonate neutralisation only) with R2 = 0.96. This correlation is valid for samples containing both non-neutralising carbonates (siderite) and sources of neutralisation arising from non-carbonates (Mg-clay) within this waste rock system. Typically, mining operations use total C measurements for assessment of carbonate neutralisation potential in the block and mining model. This method provides an effective means to cheaply analyse for carbonate neutralisation potential with assignment of potentially acid-forming and non-acid-forming blocks to waste rock cells, etc.

Numerical study of the Effect of CO2 on the NH3/CH4 Counterflow Diffusion Flame in O2/CO2/N2 Atmosphere

Ammonia, as a carbon-neutral fuel, draws people attentions recently. NH3/CH4 blends is considered as a kind of fuel. A numerical simulation of the effects of CO2 dilution on the combustion characteristics and NO emission of NH3/CH4 counterflow diffusion flame was conducted in this study. Diffusion flame structure, the influence of CO2 radiation characteristics on temperature and NO emission characteristics were studies at normal temperature and pressure. The dilution and radiation of CO2 reduce the flame temperature significantly. NO concentration decreased with the CO2 mole fraction increase effectively. The study extends the basic combustion characteristics of NH3 containing fuel.

Synthesis and Photoluminescence Properties of New Conjugated Oligoquinolines 2, 2’-Bis (4-phenylquinoline) 1, 4 Phenylene

A novel 2,2’-Bis(4-Phenylquinoline )1,4 phenylene(BPQ-P) organic phosphor was synthesized in Aragon(Ar) and Nitrogen (N2) atmosphere at 140oC by using Friedlander Condensation reaction. Based on our previously synthesized DPQ, we systemically designed some novel derivatives with tuned optical properties & the compound showed blue emission under a UV source. The synthesized organic phosphor is assessed by various characterization techniques such as FTIR and NMR spectroscopy. Using excitation and emission spectra were analysed the properties of PL in organic compounds. The synthesized organic phosphors show bright emission in the blue region, with the peaks at 483nm for 4-phenylquinoline. The physical and photoluminescence properties of these organic compounds reveal promising blue emitters for high efficiency organic light emitting diodes (OLEDS) and it may also find device applications as n-type semiconductors.