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1.
《Advanced Powder Technology》2022,33(11):103833
Eliminating the gold preg-robbing effect of carbonaceous matter in carbonaceous gold ores is crucial for gold leaching. In this study, suspension oxidation roasting was proposed to accelerate the decarbonization of carbonaceous gold ore. The characteristics of oxidation reaction process and gas release were analyzed by TG-DTA-FTIR. The phase transformation and microstructure evolution of samples during roasting were analyzed by XRD, SEM and BET. The results show that the gold preg-robbing effect was eliminated after the gasification of carbonaceous matter, and the CaO generated by decomposition of carbonates can effectively capture the SO2. After roasting for 75 min at 650 °C in a 20% O2 atmosphere, the total carbon removal rate reached 99.42%, the distribution of exposed gold increased from 28.85% to 77.10% and the gold leaching efficiency increased from 4.55% to 84.83%. In addition, about 70% sulfur was mainly fixed in the roasted products in the form of sulfate. Therefore, the suspension oxidation roasting process is an efficient and clean pretreatment method for carbonaceous gold ores. 相似文献
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《Ceramics International》2022,48(8):10506-10515
The search for materials and methods capable of reducing human impacts on the environment is of utmost importance nowadays. This study's primary purpose was to analyze the technical feasibility of ceramic composites production utilizing Fundão Dam's Iron Ore Tailings (IOT), Blast Furnace Slag (BFS) from charcoal, and Foundry Sand (FS) as partial substitutes for the traditional raw materials – sand and clay – for application in building industry materials. The composites were molded in rectangular specimens and fired at temperatures of 900, 950, 1000, 1050, and 1200 °C. The developed materials were analyzed and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetry (TGA), and Differential Thermal Analysis (DTA). The obtained materials had flexural strength modulus of up to 12.19 MPa, water absorption ranging from 2 to 22%, linear shrinkage ranging from 0.02 to 6.50%, and apparent density ranging from 2.03 to 1.63 g/cm3. The study of the internal structure formation process revealed the formation of amorphous structures in the composites. The results demonstrated that these waste materials may be jointly used in construction materials, contributing to the reduction of natural resource extraction, besides enabling their correct disposal, minimizing environmental impacts, and improving the life quality of the surrounding communities. 相似文献
4.
Understanding on the hydrogen detection of plasma sprayed tin oxide/tungsten oxide (SnO2/WO3) sensor
《International Journal of Hydrogen Energy》2022,47(33):15120-15131
The plasma spray technique was well proven in producing metal oxide based gas sensors in the last two decades using different powder feedstocks. However, limited research was made to fabricate hydrogen gas sensor from tin oxide layer coated over tungsten oxide layer. This paper attempts to interpret the hydrogen gas sensing performances of plasma sprayed coating derived by depositing tin oxide layer over tungsten oxide (SnO2/WO3) layer. Plasma sprayed SnO2/WO3 sensor showed maximum response of 90% at 150 °C in contrast to stand-alone WO3 (89% at 350 °C) and stand-alone SnO2 (89% at 250 °C). The lower operating temperature of SnO2/WO3 sensor without compromising gas response was attributed to the WO3–SnO2 hetero-junction. SnO2/WO3 sensor showed selective sensing towards hydrogen with respect to carbon monoxide and methane gases. This sensor also possessed repeatable characteristics after 39 days from the initial measurement. In a nut-shell, plasma spayed SnO2/WO3 sensor showed stability of base resistance, repeatability after successive response and recovery cycles, selective sensing towards 500 ppm H2 with significant magnitude of gas response of 90%, response time of 35 s and recovery time of 269 s at a temperature of 150 °C. 相似文献
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在总结前人钨中空位及其团簇的能量学和动力学行为的研究成果基础上,采用第一性原理方法系统计算了钨中空位及其团簇的结合能和扩散能垒。研究发现,交换关联泛函PW91和PBE较PBEsol、AM05和LDA更适合用于计算钨空位的能量学性质。基于第一性原理计算结果对文献中单空位形成能、双空位作用性质等争议性问题进行了讨论,并对钨经验势进行了评估。研究结果表明,钨中孤立单空位间总是相互排斥,而空位团簇(Vn>3)对单空位具有很强的吸引作用,其结合能随着所含空位个数增多呈现波动性增大的趋势。空位团簇稳定结构可通过最小化Wigner-Seitz表面积来确定,其结合能与Vn与Vn-1之间的Wigner-Seitz面积之差呈正比。 相似文献
7.
《Ceramics International》2022,48(9):12014-12027
The formed deposits wear out of refractory wall linings in the rotary kiln and may cause production disturbances. This study describes the chemical composition and mineralogical phase components at the deposit/refractory interface in the rotary kiln for fluxed iron ore pellets production. The main phases of refractory bricks are corundum and mullite, while the deposits mainly contain hematite and silicates. The main phases in the deposit/refractory brick contact zone are hematite, anorthite (CaAl2Si2O8), mullite, corundum, and silicates. Moreover, the hematite phases in the deposit/brick interface averagely contain 6.98 wt% Al and 1.38 wt% Ti. The silicates in the contact zone contain higher aluminium content and lower iron content than the silicates in the deposits. Finally, the thermodynamic analysis indicates that the main phases in the deposits can react with the refractory to form Al2Fe2O6, CaAl2Si2O8, feldspar, and liquid phases lead to the degradation of bricks in the kiln during the iron ore pellets production. 相似文献
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对金品位为1.55 g/t的氧化矿采用非氰药剂进行浸金的工艺流程,考察了磨矿细度、药剂DZC浓度和浸出时间对金浸出率的影响。确定该金矿适宜的非氰浸出条件:磨矿细度-74μm含量占69.90%、石灰用量4 000g/t、矿浆液固比为2∶1、浸出药剂DZC浓度0.08%、浸出时间8 h,可获得金的浸出率为93.33%的良好指标。表明该氧化金矿在常温常压下,采用非氰浸出工艺是可行的。 相似文献
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铁山头铜矿床处于铜陵矿集区的中东部,属于扬子陆块下扬子凹陷中的铜陵隆起。矿床位于凤凰山矿田北侧,成矿潜力较大。综合研究分析认为:①接触交代作用使得岩体接触带及附近变质形成矽卡岩矿化带;②区内凤凰山岩体(花岗闪长岩)系成矿母岩;③矿体主要赋存于花岗闪长岩与三叠系下统南陵湖组石灰岩接触带上;④矿床成因类型为高—中温热液交代矽卡岩型矿床。 相似文献