Prediction model of ammonium uranyl carbonate calcination by microwave heating using incremental improved Back-Propagation neural network

The incremental improved Back-Propagation (BP) neural network prediction model was put forward, which was very useful in overcoming the problems, such as long testing cycle, high testing quantity, difficulty of optimization for process parameters, many training data probably were offered by the way of increment batch and the limitation of the system memory could make the training data infeasible, which existed in the process of calcinations for ammonium uranyl carbonate (AUC) by microwave heating. The prediction model of the nonlinear system was built, which could effectively predict the experiment of microwave calcining of AUC. The predicted results indicated that the contents of U and U⁴⁺ were increased with increasing of microwave power and irradiation time, and decreased with increasing of the material average depth.     

微波辅助磨碎钛铁矿

研究微波加热对攀枝花钛铁矿磨矿性能的影响。微波辐射时间、微波功率密度和样品质量是磨矿过程的重要参数。将40g样品在微波功率1kW下辐射30s,然后进行水淬处理。SEM分析结果表明：经过微波辐射处理的钛铁矿在有用矿物和脉石间产生了裂纹,能够有效地促进矿物与脉石的解离。在随后的磁选实验中,经过微波辐射处理的钛铁矿的回收率从44%提高到72%。     

活性炭对甲苯的吸附及其等温线预测

以微波椰壳活性炭和微波再生后的活性炭吸附甲苯.测定了在20,30和40℃条件下甲苯在活性炭上的吸附等温线,采用Langmuir方程对实验数据进行拟合.结果表明,在30℃下椰壳活性炭和再生活性炭吸附甲苯的理论饱和吸附量分别为0.323 和0.273 g/g;采用Polanyi吸附势理论预测了苯在活性炭上的吸附等温线,其中...     

硫酸铵微波干燥特性及动力学模型分析

采用微波干燥技术进行了硫酸铵干燥的研究.通过系统实验分析了硫酸铵微波干燥特性,并采用薄层干燥模型进行数值分析.结果表明:修正Page模型(Ⅱ)较之其他模型更适于薄层硫酸铵微波干燥的模拟.应用Fick第二定律得到微波功率230-700 W,物料质量150-300 g条件下薄层硫酸铵微波干燥的有效扩散系数的变化范围分别为:...     

Preparation of activated carbon from Jatropha hull with microwave heating: Optimization using response surface methodology

Preparation of activated carbon has been attempted using steam as the activating agent by microwave heating from Jatropha hull. The response surface methodology (RSM) technique is utilized to optimize the process conditions. The influences of the three major parameters, activation temperature, activation time and steam flow rate on the properties of activated carbon are investigated using analysis of variance (ANOVA), to identify the significant parameters. The optimum conditions for the preparation of activated carbon has been identified to be an activation temperature of 900 °C, activation time of 19 min and steam flow rate of 5 g/min. The optimum conditions resulted in an activated carbon with an iodine number of 988 mg/g and a yield of 16.56% respectively, while the BET surface area evaluated using nitrogen adsorption isotherm correspond to 1350 m²/g, with the pore volume of 1.07 cm³/g. The activated carbon is hetero porous with the micropore volume contributing to 40.8%.     

Effects of ZrO2 Coating on LiNi1/3Mn1/3Co1/3O2 Particle with Microwave Pyrolysis

In this paper, ZrO₂-coated LiNi_1/3Mn_1/3Co_1/3O₂ is successfully prepared by the microwave pyrolysis method. The structure and electrochemical properties of the ZrO₂-coated LiNi_1/3Co_1/3Mn_1/3O₂ are investigated using x-ray diffraction, AC impedance, and charge/discharge tests, indicating that the lattice structure of LiNi_1/3Co_1/3Mn_1/3O₂ is unchanged after the coating but the cycling stability is improved. As the coating amount is 2 wt.%, initial capacity of the coated LiNi_1/3Co_1/3Mn_1/3O₂ decreases slightly. However, the cycling stability increases remarkably over the cut-off voltages of 2.75~4.3 V and the capacity retention reaches 93.1% after 50 cycles. Electrochemical impedance spectra results show that the increase of charge transfer resistance during cycling is suppressed significantly by coating with ZrO₂.     

外场强化技术在锰矿资源处理过程中的研究进展

摘要：锰矿作为一种重要的战略性资源矿产,广泛应用于钢铁、电池、农业、冶金及国防工业等领域,发挥着至关重要的战略作用。近年来,随着锰矿产业的迅速发展,中国已经成为全球第一大锰矿资源消费国,锰矿资源需求量逐年增加。基于当前锰矿仍为我国短缺矿产、需求量大,传统加工工艺在产率、可持续发展和自动化等方面出现了明显短板的实际情况,为了保障国家锰矿资源战略安全,促进我国锰矿行业的可持续发展,因此探索一种能高效、清洁、经济处理锰矿的加工方法成为国内外研究热点。研究表明,微波、超声波、流场、压力场等外场手段能高效清洁的处理矿物,并提高产品质量。因此,对微波、超声波、电场、压力场及流场等外场强化技术在锰矿处理过程中的应用研究做出了总结和思考,这对外场强化技术处理矿产资源的后续研究具有指导意义。     

Application of response surface methodology (RSM) for optimization of sintering process for the preparation of magnesia partially stabilized zirconia (Mg-PSZ) using natural baddeleyite as starting material

In this work, instead of chemical pure zirconia, natural baddeleyite was used as starting material to prepare partially stabilized zirconia (PSZ) with magnesia as stabilizer. Response surface methodology (RSM) involving central composite design (CCD) was employed to optimize the sintering process for the preparation of magnesia partially stabilized zirconia (MgO-PSZ) with the aim of improving the relative density and bending strength of the materials. The interaction between three variables i.e. sintering temperature, holding time and heating rate was studied and modeled. The statistical analysis of the results showed that in the range studied, sintering temperature had a significant effect on relative density and bending strength. The optimum combination predicted by RSM was experimentally confirmed, whereby almost complete densification with the relative density 99.44% was obtained at a 3 °C/min cooling rate.     

微波干燥过程中氯化钠电磁特性数值模拟研究

多模微波腔体是最为常见的加热腔体,然而在加热过程中待加热的物料常会表现出选择性加热的特点,这是由于微波加热的效果与物料的电磁特性参数密切相关。针对氯化钠在微波腔体中加热效果呈现出的差异性造成腔体内电磁场分布以及加热不均匀等问题,建立电磁热模型对氯化钠在加热过程中的电磁敏感性对温度变化的影响进行研究。通过时域有限差分法(Finite Difference Time Domain ,FDTD)耦合求解电磁场及热场方程,对微波加热氯化钠的升温速率随着电磁特性参数以及氯化钠含水率变化的规律进行实时的仿真计算。结果表明:随着氯化钠相对介电常数的增大,其腔体内的电场分布越均匀,介质对电磁波的吸附作用越明显。随着氯化钠损耗角和含水率的增大,腔体内氯化钠的升温速率以及稳态温度增大。     

辉钼精矿在微波场中的升温行为研究*

考察了辉钼精矿在微波场中的升温行为,研究了物料厚度、微波功率及物料量对辉钼精矿升温行为的影响。研究结果表明,辉钼精矿具有良好的微波吸收性能,物料在微波场中升温与微波功率呈正比关系,而与物料 厚度和物料量成反比。在微波功率为2.6 kW,物料厚度为2 mm条件下,微波加热13 min后,辉钼精矿可升温至 600 ℃。采用微波氧化焙烧辉钼精矿是可行的。