Comparison of the mechanisms of microwave roasting and conventional roasting and of their effects on vanadium extraction from stone coal

Experiments comparing microwave blank roasting and conventional blank roasting for typical vanadium-bearing stone coal from Hubei Province in central China, in which vanadium is present in muscovite, were conducted to investigate the effects of roasting temperature, roasting time, H₂SO₄ concentration, and leaching time on vanadium extraction. The results show that the vanadium leaching efficiency is 84% when the sample is roasted at 800℃ for 30 min by microwave irradiation and the H₂SO₄ concentration, liquid/solid ratio, leaching temperature, and leaching time are set as 20vol%, 1.5:1 mL·g-1, 95℃, and 8 h, respectively. However, the vanadium leaching efficiency achieved for the sample subjected to conventional roasting at 900℃ for 60 min is just 71% under the same leaching conditions. Scanning electron microscopy (SEM) analysis shows that the microwave roasted samples contain more cracks and that the particles are more porous compared to the conventionally roasted samples. According to the results of X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) analyses, neither of these roasting methods could completely destroy the mica lattice structure under the experimental conditions; however, both methods deformed the muscovite structure and facilitated the leaching process. Comparing with conventional roasting, microwave roasting causes a greater deformation of the mineral structure at a lower temperature for a shorter roasting time.     

EC9841型氮氧化物监测仪臭氧发生器故障的维护要点

阐述了EC9841型氮氧化物监测仪臭氧发生器故障的维护要点。     

铜锰复合氧化物低温催化氧化甲醛的性能研究

 采用简单的氧化还原方法,通过控制Cu和Mn物质的量之比及煅烧温度等条件合成了一系列铜锰复合氧化物。通过考察合成条件对催化剂的晶相、形貌以及催化活性的影响,从而确定最佳的工艺条件,结合X射线衍射（XRD）、扫描电镜（SEM）和透射电镜（TEM）等多种表征手段揭示催化剂结构和活性的关系。研究结果表明,在单一锰氧化物中,铜的掺杂促进氧物种移动,使得铜锰复合氧化物具有较低的还原温度和较强氧化还原能力,且结晶度差的无定型态同样有利于氧空穴的增加,从而有利于甲醛的催化氧化。当Cu/Mn物质的量之比为1：2、煅烧温度为300℃时制得的铜锰复合催化剂催化性能最佳,能够在90℃下完全降解甲醛。     

Microbial dissolution and stabilization of toxic metals and radionuclides in mixed wastes

Summary Microbial activity in mixed wastes can have an appreciable effect on the dissolution or precipitation of toxic metals and radionuclides. Fundamental information on microbial dissolution and stabilization (immobilization) of toxic metals and radionuclides, in particular actinides and fission products, in nuclear wastes under various microbial process conditions, e.g., aerobic, denitrifying, iron-reducing, fermentative, sulfate-reducing, and methanogenic conditions is very limited. Microbial transformations of typical waste components such as metal oxides, metal coprecipitates, naturally occurring minerals, and metal organic complexes are reviewed. Such information can be useful in the development of 1) predictive models on the fate and long-term transport of toxic metals and radionuclides from waste disposal sites, and 2) biotechnological applications of waste treatment leading to volume reduction and stabilization as wall as recovery and recycling of radionuclides and toxic metals.     

非调质钢中钛氧化物冶金行为

通过热力学计算及实验,研究了含钛汽车用非调质钢在液态和凝固过程中含钛夹杂物的析出规律.研究表明,通过调整非调质钢中O,Al和Ti的含量,可以控制夹杂的形态和尺寸,从而得到细小、弥散非金属夹杂物作为针状铁素体的形核核心,细化钢的组织,提高钢的强度和韧性.     

某些硫酸根活化氧化物的红外光谱研究

研究了硫酸铵－金属氧化物在不同温度下焙烧的ＦＴＩＲ．结果表明，经硫酸铵浸渍的ＴｉＯ２，Ｆｅ２Ｏ３和ＺｒＯ２样品，随焙烧温度的提高，硫酸根从游离状态转化为双齿键合状态，并配位至氧化物表面的金属原子，形成具有超强酸性的某种表面硫酸根对金属的配合物．而ＣａＯ，ＺｎＯ，Ｌａ２Ｏ３，ＭｎＯ２，Ｎｉ２Ｏ３和Ｍｇｏ等则没有这种现象发生，说明硫酸根不能与这类氧化物发生相互作用．     

Pillared layered transition metal oxides

This paper reviews the reecent progress in the synthesis and application of pillared transition metal oxides during the last decade ,mainly concerning the synthetic methods,structures ,physical properties and catalytic appli-cations of the laycred transition metal oxides pillared by inorganic oxides,The factors and their affecting regularity in the process of preparation,and some important results obtained in the catalytic application studies are summarized.Finally,a prospect on the potential new directions in this research area is presented.     

硝酸尾气中氮氧化物净化技术研究

介绍用酸性尿素溶液作吸收剂 ,吸收硝酸尾气中氮氧化物的净化方法。用正交试验法选择最佳工艺条件 ,并对其结果进行极差分析和方差分析。该法具有去除率高、没有第二次污染、成本低的特点     

稀土纳米复合氧化物的制备及应用

稀土纳米复合氧化物因其具有纳米材料和稀土元素的双重特性，引起了科学家的广泛关注．本文综述了稀土纳米复合氧化物的制备方法，如：高温固相反应法、共沉淀法、溶胶—凝胶法、水热合成法和燃烧合成法．总结了每种制备方法的优缺点，并对其应用前景进行了展望。