Regeneration of waste activated carbon after extracting gold with steam under microwave heating： Optimization using responsesurface methodology

The technology that waste activated carbon after extracting gold is regenerated with steam under microwave heating was studied. The influence of the activation temperature, activation duration and steam flow rate on iodine adsorption value and regeneration yield of activated carbon was investigated. The response surface methodology （RSM） technique was utilized to optimize the process conditions. The optimum conditions for the preparation of activated carbon are identified to be activation temperature of 831 ℃, activation duration of 40 min and steam flow rate of 2.67 mL/min. The optimum conditions result in an activated carbon with an iodine number of 1048 mg/g and a yield of 40%, and the BET surface area evaluated using nitrogen adsorption isotherm is 1493 m2/g, with total pore volume of 1.242 cm3/g. And the pore structure of activated carbon regenerated is mainly composed of micropores and a small amount of mesopores.     

低温一步制备氧化石墨烯及微波还原研究

以天然鳞片石墨为原料,通过低温一步氧化制备氧化石墨烯,经微波热还原得到低缺陷的还原氧化石墨烯。讨论了低温氧化过程中氧化剂用量、氧化时间对氧化石墨烯层间距、氧化程度的影响。结果表明:在高锰酸钾与天然鳞片石墨的质量比为1∶3,氧化温度为0℃,氧化时间为48h的条件下,制备出碳氧原子比为1.98、高C—O结构、低缺陷结构( I D∶ I G=0.63)的氧化石墨烯,避免了Hummers制备过程中由于CO 2的形成导致六元环断裂以及碳原子的缺失而使得氧化石墨烯的缺陷增加;经微波热还原后,得到的还原氧化石墨烯的两点平均缺陷距离 L D=12nm,缺陷密度 n D=2.21×10 11 cm -2 , I D∶ I G仅为0.85(Γ G=32.1cm -1 ),制备出低缺陷的还原氧化石墨烯。     

Al2O3基石油加氢脱硫催化剂研究现状与进展

综述了以三氧化二铝(Al_2O_3)为载体,负载Mo、Ni单一组元和Mo-Ni-W等复合组元,用于炼制石油加氢脱硫的催化剂的国内外研究现状与进展。全面总结了传统的浸渍法、混捏法、共沉淀法、离子交换法以及新型的微波-超声波法等催化剂合成方法,对Al_2O_3基催化剂的加氢脱硫性能进行了讨论,着重对催化剂合成过程中载体、活性组分、助剂(P、F、B等)和pH值对催化剂性能的影响进行了概述,在此基础上总结了Al_2O_3基加氢脱硫催化剂的不足之处,并展望了此类催化剂的发展方向与研究前景。     

拌酸熟化法从含锗渣中浸出锗的试验研究

含锗渣是锌湿法冶炼的中间产物,其主要物相为硫酸铅,并富集了大量的锗。为了最大限度的浸出锗,从含锗渣的组成和性质出发,利用锗的一些化合物能够溶于酸中,采用拌酸-熟化-洗涤工艺浸出锗,获得了含锗762 mg.L-1的浸出液。重点研究了加水量、拌酸量、熟化温度和熟化时间对锗浸出率的影响,实验结果表明:拌酸熟化最佳加水量和酸量都为渣重的50%,熟化温度80℃,熟化时间3 h,在此条件下锗浸出率为71.6%,此工艺具有浸出率高、流程短、易过滤等特点。     

微波加热钛精矿试验建模及温度控制器设计

微波加热物料是一个复杂的过程。在加热的过程中,物料温度会受到介质物理参量的温变等因素的影响。通过开展微波加热钛精矿试验,获取试验数据,并得到飞升曲线;结合Cohn Coon公式和温控对象的特点,建立微波加热钛精矿的对象模型。在此模型的基础上,分别采用经典PID和Smith预估两种控制策略,对微波加热过程中的温度进行控制;利用Matlab环境下的Simulink工具,对两种控制过程进行仿真分析研究,并对其结果进行比较分析。分析结果表明,经典PID策略有明显局限。它对具有大时滞、非线性、时变性,以及不确定性等复杂性特征的系统(微波加热等)的控制效果不理想。而采用具有鲁棒性的Smith预估策略,能够极大程度地减小微波加热过程中的超调量,使控制性能得到提升。     

Thermogravimetrically and differential scanning calorimetrically derived kinetics of oil shale pyrolysis

Thermogravimetry (TG) and differential scanning calorimetry (d.s.c.) were used to investigate the kinetics of non-isothermal pyrolysis of Aleksinac oil shale from Yugoslavia. The samples used included oil shale, demineralized oil shale and bitumen extracted from the original, as well as from the thermally treated oil shale.Kinetic parameters were determined by assuming a single first-order kinetic model, using the integral method for TG analysis, and ASTM procedure E-698 for d.s.c. analysis. The influence of cracking catalyst addition was examined with respect to the overall kinetics and to conversion in particular temperature regions.Higher values of kinetic parameters were obtained by d.s.c. analysis, and the reasons for the differences between those and the TG results are discussed.     

One and two electron transfer at low collision energy: Spectroscopic case studies

A comparative study of single and double electron transfer is made considering ions with an initial charge of 8 + (O⁸⁺, Ne⁺ , Ar⁸⁺) colliding with He at energies of a few keV/amu. It is shown that even though single capture populates n = 4, the dynamics of the process is different. Furthermore double capture being possible, mostly via a two step process in one collision, it appears that stabilization changes significantly in these three cases from mostly autoionizing to mostly radiative.     

微波加热技术在典型冶金工艺中的应用研究进展

阐述了微波加热的基本原理,讨论了矿物在微波场中的升温特性和吸波特性。微波在矿物处理方面的应用研究进展,主要包括微波预处理、微波干燥、微波焙烧、微波碳热还原、微波辅助浸出等典型冶金工艺的研究现状。分析了目前微波加热技术在典型冶金工艺中的应用与研究进展,并对微波加热技术在冶金工艺中的应用前景进行了展望。     

微波焙烧攀枝花钛渣实验研究

由于氯化法钛白工艺及电焊条产业的迅速发展,对高品位人造金红石的需求呈现快速增长的趋势。进行了攀枝花钛渣微波焙烧试验,考察了不同焙烧温度对钛渣样品的重量、二氧化钛品位、脱硫及脱碳效果的影响。结果表明,钛渣在微波焙烧条件下,低价钛逐渐氧化成高价钛,随着焙烧温度的提高,氧化效果越好,样品重量的增重先升高后降低,同时二氧化钛品位呈现先降低后升高的趋势,且硫、碳含量因为在焙烧过程中与氧气反应生成SO2、CO及CO2逸出而减少。     

湿法炼锌泥的微波干燥实验

目前回转窑干燥物料的方法主要存在干燥时间长、环境污染严重、效率低等缺点,为了解决这一问题,开展了微波干燥湿法炼锌泥的实验研究,采用实验室自制的微波干燥设备,考察微波功率、干燥时间以及物料质量对样品脱水率的影响。研究结果表明:在一定条件下,脱水率随干燥时间延长而增加,随着微波功率的增加而提高,随物料质量增加而降低。实验在微波功率600W、物料质量40g、微波加热时间3min时,湿法炼锌泥的脱水率达到99.57%;FT-IR分析可知,干燥后波数1625cm^-1和3300cm^-1附近水分子的伸缩振动峰基本消失,说明微波干燥后物料基本不含水分;与常规干燥进行比较,微波干燥湿法炼锌泥具有干燥时间短、脱水效率高、清洁无污染的优点,是一种高效节能的新型干燥方法。