Anodic dissolution of gold in alkaline solutions containing thiourea, thiosulfate and sulfite ions

Gld dissolves electrochemically in alkaline solutions containing ligands to form complex ions with gold ion.Therefore,selective leaching of noble metals is expected without dissolution of base metals such as steels,aluminum alloys in scrap treatment.Gold electrodes were investigated using linear sweep voltammetry,EQCM method and potentiostatic eclectrolysis in alkaline solutions containing thiourea,Na2SO3 and Na2S2O3.The solution composition,electrode potential affect gold dissolution rate and current efficiency.The gold dissolved from anode electrode forms complex ions,suspension particles as compound precipitates and deposits on cathode electrode as a metal.Anodic efficiency for gold dissolution is between 10% and 22%.This is caused by the oxidation decomposition of sulfite ions and thiourea.The statbility of the alkaline solution containing these elements was also estimated by capillary electrophoresis technique.     

Bioleaching of refractory gold ore （ Ⅲ ）——Fluid leaching Jinya refractory gold concentrate by Thiobacillus ferrooxidans

A novel fluidized-bed reactor was designed and installed for bloleaching in a semi-continuous way, by which a process for biuleaching-cyanidation of Jinya refractory gold arsenical concentrate was studied. The arsenic extraction rate reaches 82.5 % after 4-day batch biooxidation of the concentrate under the optimized condition of pH 2.0, ferric ion concentration 6.Sg/L and pulp concentration 10%. And leached rate of gold in the following cyanida.tion is over 90%. The parameters of three series fluidized-bed reactors exhibit stability during the semi-continuous bioleaching of the concentrate.Armmic in the concentrate can be got rid of 91% after 6-day leaching. Even after 4 days, 82% of arsenic extraction rate was still obtained. The recovery rates of gold are 92 % and 87.5 % respectively in cyaniding the above bioleached residues.The results will provide a base for further commercial production of gold development.     

圈数计在可逆可冷轧机上的应用

采用准确计圈方式可实现可逆式冷轧机的自动准确停车，介绍了此方法的硬件配置和基本控制原理，可作为同类型生产线的参考。     

增塑剂环己烷-1,2-二甲酸酯的绿色合成及性能研究

采用硫酸氢盐/金属单质复合催化剂,以环己烷-1,2-二甲酸酐(HHPA)和正丁醇为原料,合成了增塑剂环己烷-1,2-二甲酸二丁酯(DBCH).最佳工艺条件为:以NaHSO4·H2O/Fe为催化剂,醇酐物质的量比2.5:1,催化剂用量为醇酐总质量的3‰,催化剂粒径为150μm(100目),反应温度155～160℃,反应时间4 h,酯化率可达99.78％,纯度>99％.复合催化剂催化活性高,可回收,安全、经济且环境友好.考察了DBCH对聚氯乙烯制品脆化温度、力学性能、挥发性和耐迁移性能的影响,与纯的PVC树脂相比较,DBCH具有较好的增塑性能.     

筑炉方式对中频感应炉炉衬寿命的影响

采用了不同振动器在中频无芯感应电炉上打结干振料的工艺,分析了影响中频感应电炉炉衬寿命的因素,研究了不同筑炉方式对电炉炉衬寿命的影响。实践表明,采用Jolter振动器打结干振料工艺,使炉衬寿命从单炉160炉提高至180炉,平均增加12．50％。     

催化氧化含邻甲苯酚废水的研究

纳米级铁氧化合物(自制)用作催化剂催化H2O2对含邻甲苯酚废水进行催化氧化降解实验,通过单因素实验确定了处理含邻甲苯酚废水的最佳条件为:H2LO2浓度为20%,催化剂用量为0.8g,反应温度为80℃.处理模拟废水,邻甲苯酚(1000ppm)的去除率大于99%,农药行业废水中邻甲苯酚(1150ppm)的去除率大于95%.实验表明该催化剂可以进行多次循环使用.     

聚间苯二胺胺化改性及其对SO42-的吸附性能

采用化学氧化法制备聚间苯二胺,并采用环氧氯丙烷及三乙烯四胺等多胺为原料,制备一类新型改性聚间苯二胺。研究溶剂等不同因素对合成反应及其硫酸根离子吸附的影响,并利用FTIR、TG及溶解性测试等进行结构性能表征。结果表明:与未改性聚间苯二胺相比,胺化改性后的聚间苯二胺吸附硫酸根离子的性能得到大幅提升,在本研究吸附条件下,其吸附量达到了187.5 mg/g。胺化改性可以降低改性聚间苯二胺的溶剂溶解性,在40~250℃范围内,其热稳定性也有所提高。对聚间苯二胺合成改性的机理进行了初步探讨。     

流动注射化学发光法研究桔子皮提取液的抗氧化性

以桔子皮为原料,研究提取桔子皮活性物质的最佳工艺及其抗氧化性.采取超声辅助法对桔子皮中消除超氧阴离子的活性物质进行提取,通过单因素实验对提取工艺进行了优化,利用Luminol-邻苯三酚-Na2CO3化学发光体系评价了桔子皮提取液消除超氧阴离子的能力.结果表明,在温度为60℃、80％的乙醇为提取剂、料液比为1:20、超声...     

高职数控机床编程与操作实训教学手段的创新与实践

数控机床编程与操作实训教学手段在不断改革与创新中。我们运用数控加工的仿真软件让学生在虚拟加工中得到充分的训练,然后在真实的生产设备上进行加工,使学生数控编程与数控机床操作及运用软件的能力得到较大提高,获得了较好的教学效果。     

高沙电站坝顶门机及液压清污抓斗的使用情况

论述了我国第1台具有清污功能的门机的结构形式和国内第1套液压清污抓斗的结构形式和工作原理。介绍了液压清污抓斗的使用情况和存在的问题，以供解决电站清污问题的有关单位参考。