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Thermoanalysis was used in this research to produce a comparative study on the combustion and gasification characteristics of semi-coke prepared under pyrolytic atmospheres rich in CH4 and H2 at different proportions. Distinctions of different semi-coke in terms of carbon chemical structure, functional groups, and micropore structure were examined. The results indicated that adding some reducing gases during pyrolysis could inhibit semi-coke reactivity, the inhibitory effect of the composite gas of H2 and CH4 was the most observable, and the effect of H2 was higher than that of CH4; moreover, increasing the proportion of reducing gas increased its inhibitory effect. X-ray diffractometer and Fourier-transform infrared spectrometer results indicated that adding reducing gases in the atmosphere elevated the disordering degree of carbon microcrystalline structures, boosted the removal of hydroxyl- and oxygen-containing functional groups, decreased the unsaturated side chains, and improved condensation degree of macromolecular networks. The nitrogen adsorption experiment revealed that the types of pore structure of semi-coke are mainly micropore and mesopore, and the influence of pyrolytic atmosphere on micropores was not of strong regularity but could inhibit mesopore development. Aromatic lamellar stack height of semi-coke, specific surface area of mesopore, and pore volume had a favorable linear correlation with semi-coke reactivity indexes.

Metal magnesium is mainly produced from the calcined dolomite by the silicothermic production. However, in this process, the reduction temperature is higher while the reaction speed is slow, which results in higher energy consumption and serious environmental problems. In this paper, adding aluminum into the ferrosilicon reducing agent is expected to lower the reaction temperature so as to solve the problems above. The phase transition involved in the whole reduction process including with and without aluminum addition were investigated in details by theoretical calculation and experimental research. The influence of aluminum on the magnesium oxide reduction path was analysis to clarify the internal mechanism. The results show that aluminum added into the ferrosilicon would first react with magnesium oxide to form magnesium vapor and alumina under vacuum pressure of 10 Pa when the temperature rises to 720°C. Then, calcium aluminate would be formed by the reaction of aluminum oxide and calcium oxide. Once the temperature reaches 1150°C, silicon begins to reduce the magnesium oxide to create the silicon oxide that will finally react with calcium oxide to form calcium silicate. When the temperature rises above 1150°C, both the aluminum and silicon will participate in the reduction of magnesium oxide. In the process of heating up, the mixture of aluminum, ferrosilicon and calcined dolomite forms Mg2Al4Si5O18 and Ca3Al2(OH)12 phase with the components in calcined dolomite. Mg2Al4Si5O18 and Ca3Al2(OH)12 phase finally form Ca12Al14O33 phase. The interaction between aluminum and ferrosilicon in the mixture is less; the mixture of aluminum and ferrosilicon first forms Al3FeSi2 phase, and finally has the trend of forming Al4.5FeSi phase. There is a great difference between the phase transformation of aluminum in the mixture of aluminum, ferrosilicon and calcined dolomite and that of aluminum in the mixture of aluminum and ferrosilicon.

Jarosite residues in zinc hydrometallurgy are considered as hazardous waste as they contain heavy metals such as Zn and Pb. A novel vacuum reduction and distillation process has been put forward to recover Zn and Pb from jarosite residues. Four main factors including the amount of coke powder, amount of lime powder, heating temperature, and holding time which have an influence on volatilization of Zn and Pb were studied in this paper by the statistical software JMP. The results show that heating temperature is the key factor among the four contributing factors. By examination of the relationship between the four factors and the volatilization of Zn and Pb, it is indicated that a heating temperature of 1000°C, holding time of 90 min, and addition of 29.6% coke powder and 13% lime powder to the residues led to optimum ratios of 99.4% of both Zn and Pb volatilization. The results show that this process is an effective method in dealing with zinc, lead, and iron in jarosite residues and it is an environment-friendly process.

The decrease in the zinc volatilization rate is usually due to the liquid phase, which is typically generated in the rotary kiln. The response surface model was built to analyze and explore the effects of carbon content, basicity, and holding time on the zinc volatilization rate and residue state. Moreover, the model was used to optimize the experimental conditions. The results showed that the effect of basicity on zinc volatilization rate was statistically significant, whereas the effects of carbon content and holding time were relatively small. The optimized process conditions were as follows: carbon content of 32%, basicity of 3, and holding time of 30 min. Under this condition, the zinc volatilization rate was 99.65%, and the furnace residue was sintered, which proved to be beneficial to the subsequent step of iron extraction.

Vast jarosite residue was produced from traditional zinc hydrometallurgy process in China. It is necessary to recover valuable metals from the jarosite residue. Indium is the one of them. Recovering indium from jarosite residues with carbon reduction method under the condition of vacuum was investigated. The analysis of variance was used to evaluate the influence of different factors on the volatilizing rate of indium, indicating that the influence of temperature on the volatilizing rate of indium is statistically significant. Other factors have no significant influence. Response surface methodology was used to explore the best combination of four variables and to study the effects of their interactions on the indium volatilizing rate. The results showed that there was an obvious interaction between the percent content of carbon and temperature and between the percent content of carbon and hold time, and the selected optimal conditions were 30% carbon, 13% CaO, 1000°C temperature, and 60 min hold time. Under these conditions, the indium volatilization rate was up to 98.2%.

In this paper, the removal of arsenic from arsenic-bearing gold ore through air oxidation and sodium hydroxide leaching with microwave irradiation was studied. Firstly, single-factor experiments were carried out. The results indicated that the removal rate of arsenic was influenced by the sodium hydroxide concentration, ratio of liquid to solid, microwave power, and reaction time. Then, orthogonal experiments were done to determine the main influencing factors. The results obtained from the experiments of orthogonal arrays showed that reaction time and microwave power were the important influencing factors, and the optimum conditions of sodium hydroxide concentration, reaction time, microwave power, and ratio of liquid to solid were 18 wt.%, 60 min, 700 W, and 5, respectively. Under the optimal conditions, the removal of arsenic could reach approximately 81.46 wt.% and, at the same conditions, the sulfur removal rate was about 55.56 wt.%. The results of X-ray diffraction analysis revealed that AsS and FeAsS were decomposed during the leaching process, while FeS2 was not.

Thermoanalysis was used in this research to produce a comparative study on the combustion and gasification characteristics of semi-coke prepared under pyrolytic atmospheres rich in CH4 and H2 at different proportions. Distinctions of different semi-coke in terms of carbon chemical structure, functional groups, and micropore structure were examined. The results indicated that adding some reducing gases during pyrolysis could inhibit semi-coke reactivity, the inhibitory effect of the composite gas of H2 and CH4 was the most observable, and the effect of H2 was higher than that of CH4; moreover, increasing the proportion of reducing gas increased its inhibitory effect. X-ray diffractometer and Fourier-transform infrared spectrometer results indicated that adding reducing gases in the atmosphere elevated the disordering degree of carbon microcrystalline structures, boosted the removal of hydroxyl- and oxygen-containing functional groups, decreased the unsaturated side chains, and improved condensation degree of macromolecular networks. The nitrogen adsorption experiment revealed that the types of pore structure of semi-coke are mainly micropore and mesopore, and the influence of pyrolytic atmosphere on micropores was not of strong regularity but could inhibit mesopore development. Aromatic lamellar stack height of semi-coke, specific surface area of mesopore, and pore volume had a favorable linear correlation with semi-coke reactivity indexes. [ABSTRACT FROM AUTHOR]

The electro-optic response of epitaxially strained SrTiO3 grown on bulk DyScO3 substrates is measured as a function of applied in-plane bias (both magnitude and direction) and light polarization. The effective electro-optic coefficients are bias-field dependent. Hysteresis is observed at room temperature, indicative of residual polarity, which is believed to be due to long-lived alignment of nanopolar regions possibly due to defects. A simple model incorporating non-180°-nanoscale domains can account for most of the experimental observations. [ABSTRACT FROM AUTHOR]

The electro-optic response of epitaxially strained SrTiO3 grown on bulk DyScO3 substrates is measured as a function of applied in-plane bias (both magnitude and direction) and light polarization. The effective electro-optic coefficients are bias-field dependent. Hysteresis is observed at room temperature, indicative of residual polarity, which is believed to be due to long-lived alignment of nanopolar regions possibly due to defects. A simple model incorporating non-180°-nanoscale domains can account for most of the experimental observations. [ABSTRACT FROM AUTHOR]

Experimental studies were carried out to find the difference of preheating characteristics of Datong coal in O2/CO2 and air atmospheres by a circulating fluidized bed. It is found that pulverized coal could be both steadily preheated to above 800°C in the two different atmospheres, but the temperature distribution was more uniform along the riser in O2/CO2 atmosphere. During the preheating, the content of CO in the flue gas can reach 12.32% under the O2/CO2 atmosphere, far higher than that in air (5.94%). Simultaneously, the conversion rate of fixed carbon was higher in O2/CO2 atmosphere compared with that in air. It can be inferred the higher oxygen concentration and higher partial pressure of CO2 have greatly accelerated the gasification reaction. The BET analysis indicated a number of large pores were transformed into micropores during the preheating progress, and the major contributors for overall pore volume of chars and specific surface area are the micro-pores and the mesopores with diameter ranging from 2 nm to 10 nm. The inner pore structure was more developed in O2/CO2 atmosphere. [ABSTRACT FROM AUTHOR]

Optical coherence tomography (OCT) provides high-resolution, cross-sectional imaging of tissue microstructure in situ and in real time, while fluorescence molecular imaging (FMI) enables the visualization of basic molecular processes. There is a great deal of interest in combining these two modalities so that the tissue's structural and molecular information can be obtained simultaneously. This could greatly benefit biomedical applications such as detecting early diseases and monitoring therapeutic interventions. In this research, an optical system that combines OCT and FMI was developed. The system demonstrated that it could co-register en face OCT and FMI images with a 2.4 x 2.4 mm(2) field-of-view. The transverse resolutions of OCT and FMI of the system are both approximately 10 microm. Capillary tubes filled with fluorescent dye Cy 5.5 in different concentrations under a scattering medium are used as the phantom. En face OCT images of the phantoms were obtained and successfully co-registered with FMI images that were acquired simultaneously. A linear relationship between FMI intensity and dye concentration was observed. The relationship between FMI intensity and target fluorescence tube depth measured by OCT images was also observed and compared with theoretical modeling. This relationship could help in correcting reconstructed dye concentration. Imaging of colon polyps of the APC(min) mouse model is presented as an example of biological applications of this co-registered OCT/FMI system.