The liquid Miscibility Gap and the Distribution of Silver Between Speiss and Metallic Lead in the Pb-Fe-As, Pb-Cu-As and Pb-Fe-Cu-As System at 1200℃

The liquid miscibility gap and the distribution of silver between speiss and metallic lead for the Pb-Fe-Cu-As quarternary system have been determined at 1200℃. The miscibility gap in the Pb-Fe-As system covered a wide composition range. Molten lead containing a small amount of arsenic equilibrated with the speiss which consisted of iron arsenide with a small quantity of dissolved lead. The miscibility gap in the Pb-Cu-As system was also determined. In this system, the solubility of lead in speiss had a minimum with increasing arsenic content. In the quarternary system, the region of immiscibility was found to be distributed between the above, two, ternary systems on a pseudoternary phase diagram and was dependent on the cu/Fe+Cu ratio in speiss. The arsenic content in molten lead increased sharply beyond a definite quantity of arsenic in speiss. The behaviour of the distribution ratio of silver, K_, defined as wt.% Ag in speiss/wt.% Ag in metallic lead was summarized as follows : (1) In the Pb-Fe-As system, the values for K_ were low when the arsenic content in speiss was below 40% ; but above this range, the values increased sharply. (2) In the Pb-Cu-As system, K_ was around 1.2 for all speiss compositions investigated. (3) In the Pb-Fe-Cu-As system, the value of K_ was distributed between those obtained for the two ternary systems. The distribution ratios of silver derived from practical data agreed well with present work. From these results, a pyrometallurgical process in which lead and precious metals are recovered as bullion and in which arsenic is fixed and discarded as iron arsenide speiss can be proposed

Thermodynamic Evaluations of Extractive Metallurgical Processes

Among the various, possible applications of thermodynamics to extractive metallurgical processes, the availability of chemical potential diagrams and calculation methods combining stoichiometric relations with equilibrium constants are emphasized. In hydrometallurgical processes, the value of potential-pH diagrams has been well recognized and the application of similar techniques to rather complex systems containing ligands such as the cyanidation process is very interesting. In the roasting of sulfide ores, various information is derived from sulfur-oxygen potential (log P_-log P_) diagrams. Especially convenient for sulfation roasting are the SO_2-O_2 potential diagrams. Various smelting processes including the direct production of metal from sulfide ore are discussed with the use of chemical potential diagrams. Based upon the prediction derived from sulfur-oxygen potential diagram, the recovery of elemental sulfur from oxidation of FeS is evaluated by stoichiometric calculations. Volatilization behaviour of elements such as zinc, cadmium, and mercury are also explained by similar diagrams and the possibility of the direct distillation of zinc sulfide is predicted by stoichiometric calculations. Analogous calculations are used to clarify the reasons why the segregation process is amenable to copper oxide ore but not to nickel ore

Twist glass transition in regioregulated poly(3-alkylthiophenes)s

The molecular structure and dynamics of regioregulated poly(3-butylthiophene) (P3BT), poly(3-hexylthiophene)(P3HT), and poly(3-dodecylthiophene) (P3DDT) were investigated using Fourier transform infrared absorption (FTIR), solid state $^{13}$C nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC) measurements. In the DSC measurements, the endothermic peak was obtained around 340 K in P3BT, and assigned to enthalpy relaxation that originated from the glass transition of the thiophene ring twist in crystalline phase from results of FTIR, $^{13}$C cross-polarization and magic-angle spinning (CPMAS) NMR, $^{13}$C spin-lattice relaxation time measurements, and centerband-only detection of exchange (CODEX) measurements. We defined this transition as {\it twist-glass transition}, which is analogous to the plastic crystal - glassy crystal transition.Comment: 9 pages, 10 figures, 2 tables. Phys.Rev.B, in pres

Study on Energy-Saving Performance of a Novel CO2 Heat Pump with Applications in Dairy Processes

In dairy processes, there are significant simultaneous heating and cooling demands. A novel type of transcritical CO2 heat pump system is proposed, and its features and benefits are introduced. Bassed on the technical characteristics, primary energy-savings, and operating cost aspects, the CO2 heat pump system is simulated and compared to current heating and cooling systems used in dairy plants. The results show that the highest primary energy-saving rate of the CO2 heat pump is 51.5%. For fluid milk and cheese manufacturing processes, the primary energy-saving is 36.2% and 45.1%, respectively. In addition, the operating cost savings of fluid milk and cheese production are evaluated based on the cost structures in the states of Wisconsin, California and New York

Analysis of a Data Center Using Liquid-Liquid CO2 Heat Pump for Simultaneous Cooling and Heating

Liquid–liquid CO2 heat pump systems are a promising technology for commercial building applications, which require simultaneous heating and cooling. This paper presents the investigation of a data center on the Purdue University, West Lafayette campus. The data center located in the Department of Mathematics is the most energy intensive data center on campus. The cooling load of the data center is approximately 750 kW/hour. The heating season in West Lafayette is 7 to 8 months and the heating load of the buildings is very high during the coldest months. The heating load of the Mathematics building can go to as high as 600 kW/hour during the coldest days of the year. To suffice this simultaneous cooling and heating demand, a liquid-liquid CO2 heat pump is proposed. Presently, the cooling load of the data center is met by eight electrically driven and four steam-driven chillers and the heating load is satisfied by two coal fired and two natural gas boilers. Simulations are performed to compare the proposed CO2 heat pump system with the present system. The assessment shows noteworthy fuel savings and reduction in the CO2 emissions with the system working with a coefficient of performance (COP) of 6.19. If the CO2 heat pump system is installed, 574.92m3/day of natural gas and 751.68 kg/day of coal could be saved on a cold day. The system has the potential to reduce CO2 emissions by 2980.76 kg/day

Cost Optimization of Thermoelectric Sub-Cooling in Air-cooled CO2 Air Conditioners

This paper presents a cost-effective enhancement of a trans-critical carbon dioxide (CO2) cycle in air-conditioning mode by utilizing a thermoelectric sub-cooler. It is well-documented that the cooling COP of the transcritical CO2 cycle decreases as the ambient air temperature significantly increases above the critical temperature of the refrigerant. A high gas cooler outlet temperature limits the enthalpy of evaporation so that the air-conditioning cooling performance is reduced. Sub-cooling is known as a mitigation method to this problem. However, adding a small-scale heat pump to a residential or light commercial air conditioner can be quite costly. Therefore, a thermoelectric solid-state sub-cooler is proposed. The thermoelectric cooling (TEC) devices utilized in small temperature differences ranging from 5 to 15 oC can be quite efficient since the intrinsic heat loss of the TEC by heat conduction in reverse direction of pumping heat is minimal. Based on the prior work, the optimum design for cost-per-performance shows that the cost for sub-cooling is dominated by the heat exchangers and it is not by the thermoelectric material itself. The TECs are compact and have a low thickness, which is in the range of a few mm. Hence the TEC modules can be integrated into the form factor of a plate heat exchanger. In this study, the cooling COP of the CO2 air conditioner is enhanced by approximately 12% using an optimally designed thermoelectric sub-cooler at an ambient temperature of 35 oC. This potential improvement is based on a figure-of-merit (ZT) of currently available thermoelectric materials (ZT~1). The seasonal primary energy efficiency and the cost performance of the optimized TE sub-cooled CO2 heat pump system will be presented in comparison to other compact sub-cooling technologies

Mineralogy of Y-981971 LL Chondrite and Brecciation Processes of the LL Parent Body

第3回極域科学シンポジウム/第35回南極隕石シンポジウム 11月30日（金） 国立国語研究所 2階講

Experimental Study of a CO2 Thermal Battery for Simultaneous Cooling and Heating Applications

This paper presents experimental investigations of the dynamics of a transcritical CO2 heat pump system with two thermal storages for simultaneous cooling and heating application. The preliminary results of the thermal battery are provided using a small-scale test bed that shows the accelerated penetration of renewable energy sources for building heating and cooling applications. The experimental system consists of a CO2 heat pump system with a compressor of 3 kW (1.02x104 BTU/hr) cooling capacity and two water tanks. During operation, the compressor and expansion valve are considered quasi-static. Thermal sensors are located in each of the two tanks to monitor the temperature gradient of water along the vertical orientation of the tank which impacts the overall system performance. Experiments are carried out under different water circulation flow rates for both the gas cooler and the evaporator in the heat pump, as well as under various discharge pressure conditions controlled by different charging rates and expansion valve openings. The impacts of water circulation flow rate and valve opening are reported in an effort to find the optimum coefficient-of-performance (COP). The results show that increasing the water inlet temperature in the gas cooler raises the discharge pressure significantly and drops the COP, whereas increasing the water temperature of the evaporator raises the discharge pressure relatively moderately. Although a larger water flow rate enhances the heat exchanger capacity and system COP, a smaller water flow rate seems to be preferable to maintain the thermal profile of the water tanks and to provide a more stable COP. At higher gas cooler water inlet temperature, the COP tends to increase with closing expansion valve. In this particular setup, the best COP is found to be approximately 7.0 at a specific expansion valve opening and at a discharge pressure between 75 and 83 bars (1088 to 1204 psia). The heating COP negatively corresponds to the water temperature at the gas cooler inlet. Experiments suggest the need of a proper control strategy and a matched tank capacity design. Based on these results, a 20% power enhancement may be possible by controlling the hot and cold water flow rates

The Behaviour of Lead in Silica-Saturated, Copper Smelting Systems

The equilibrium distribution coefficients of lead between the matte, slag and metallic phases in the silica-saturated, copper smelting system were determined. These experiments were carried out by simultaneously equilibrating the various phases in silica crucibles at 1300℃. The conditions investigated in this study ranged from iron and copper alloy saturation at low oxygen potentials to a sulfur dioxide partial pressure of 0.1 atm and up to a matte grade of 75 wt. % Cu. The lead was found primarily in matte except in the presence of the copper alloy phase. The accumulation of lead in the copper alloy phase was pronounced, particularly at low oxygen potentials. Under conventional smelting conditions, the lead content in slag increased with increasing matte grade. The behaviour of lead was explained by proposing metallic and sulfidic species in matte and oxidic and sulfidic dissolution in slag. In this manner, the activity coefficients of the various species were calculated in their respective phases