生物冶金技术的研究现状及发展趋势

低品位矿产资源的开发利用制约着全球绿色可持续发展,生物冶金技术是实现矿物加工和有色金属冶金领域绿色可持续发展的前沿性技术,同时在矿山重金属污染场地原位修复中发挥重要作用。综述了生物冶金技术的基本概念、微生物生理特征和作用机制,以及生物冶金在硫化铜矿浸出、难处理金矿氧化预处理、铀矿浸提、稀土提取等方面的应用和研究现状,提出未来应针对高效浸出微生物选育、生物浸出界面作用机制、高效节能装置和工程化技术等方面开展研究,并进一步拓展生物冶金技术研究及应用领域。

嗜酸铁氧化细菌生物矿化研究进展及其应用

重点介绍嗜酸铁氧化细菌的胞内胞外矿化研究进展,概述嗜酸铁氧化细菌胞内矿化产物性质和影响矿化产物合成的因素,整理现阶段磁性纳米颗粒的合成机制;对嗜酸铁氧化细菌胞外矿化产物的合成原理和影响因素进行汇总;最后总结嗜酸铁氧化细菌矿化产物的应用前景,并指出当下磁性纳米颗粒研究的不足。针对研究现状提出未来依赖分子生物学解析胞内矿化机制并拓展其应用范围的新思路,该研究有望为进一步研究嗜酸铁氧化细菌胞内胞外矿化及其应用提供理论指导。

可见光和银离子对p型和n型黄铜矿生物浸出的影响机理

研究可见光和银离子(Ag^(+))对嗜酸氧化亚铁硫杆菌浸出p型和n型黄铜矿(黄铜矿A和黄铜矿B)的不同影响及机理。通过霍尔效应试验、生物浸出试验、X射线衍射、扫描电子显微镜和X射线光电子能谱对黄铜矿的半导体性质、生物浸出行为、表面形貌、主要物相和表面物种进行分析。实验结果表明,黄铜矿A比黄铜矿B具有更高的载流子浓度和更大的载流子迁移率,因此其溶出速率更快。生物浸出24 d后,当光照和Ag^(+)同时存在时,黄铜矿A的铜浸出率为91.05%,比黄铜矿B的铜浸出率(73.19%)高17.86%。显然,可见光和Ag^(+)对黄铜矿A生物溶解过程的促进作用强于黄铜矿B,这主要归因于黄铜矿A具有更高的载流子迁移率。此外,在光照影响下,黄铜矿表面电荷转移加快,导致Ag2S积累增多(特别是黄铜矿A),从而导致钝化层致密结构被破坏,钝化效果降低,黄铜矿溶解加速。

四川菜用大豆产业发展现状及对策

经过十多年发展,四川菜用大豆种植面积位居全国前列,生产区域以成都为中心,扩大到德阳、绵阳、内江、自贡、宜宾等生产力和光热条件较好的地区。四川菜用大豆具有上市早、持续供应时间长、产量高的鲜明特点,其中80%外销,为国内消费者提供了优质高蛋白蔬菜,也是川内菜农的重要收入来源,菜农种植积极性高。通过对四川菜用大豆的产业现状进行充分调研,剖析了产业链中存在的品种单一、重茬连作严重、栽培技术不规范、采摘困难、保鲜期短等主要问题,提出了优化种植区域、加大品种选育力度、采摘机械化、保鲜技术研发、产品多元化开发等对策建议。

Catalytic effect of silver-bearing solid waste on chalcopyrite bioleaching:A kinetic study

Silver ion can be useful in improving chalcopyrite bioleaching efficiency.In this work,leaching kinetics of this process was investigated using silver-bearing solid waste under different chalcopyrite/solid waste ratios.Bioleaching behavior indicates that silver-bearing solid waste can enhance the bioleaching process,and the redox potential is much higher than the proposed appropriate range(380−480 mV vs Ag/AgCl)with the solid waste added.There is a positive correlation between temperature and copper extraction rate.The kinetics data fit well with the shrinking-core model.Under these leaching conditions,the bioleaching of chalcopyrite is controlled by internal diffusion with calculated apparent activation energy(Ea)of 28.24 kJ/mol.This work is possible benificial to promote the industrial application of silver catalyst in leaching of chalcopyrite.

Sulfide mineral bioleaching:Understanding of microbe-chemistry assisted hydrometallurgy technology and acid mine drainage environment protection

Bioleaching is regarded as an essential technology to treat low grade minerals,with the distinctive superiorities of lower-cost and environment-friendly compared with traditional pyrometallurgy method.However,the bioleaching efficiency is unsatisfactory owing to the passivation film formed on the minerals surface.It is of particular interest to know the dissolution and passivation mechanism of sulfide minerals in the presence of microorganism.Although bioleaching can be useful in extracting metals,it is a double-edged sword.Metallurgical activities have caused serious environmental problems such as acid mine drainage(AMD).The understanding of some common sulfide minerals bioleaching processes and protection of AMD environment is reviewed in this article.

财务管理理论与实践的风险管理研究

就在社会主义市场经济不断活跃的前提之下，企业面对的竞争压力越来越大，想增强企业的核心竞争力，就需增强企业的内部管理能力。企业的日常经营活动是为了获得经济效益，财务管理是企业管理的重组成部分，根据国家相关的企业管理指导政策，企业的财务管理应该注重风险管理的相关手段。本文简单介绍财务管理学习过程中理论与实践相结合的过程，以及关于风险管理的相关研究。

Synthesis of intracellular cobalt ferrite nanocrystals by extreme acidophilic archaea Ferroplasma thermophilum

Ferroplasma thermophilum,a sort of extreme acidophilic archaea,which can synthesize intracellular cobalt ferrite nanocrystals,is investigated in this study.The nanocrystals were analyzed with ultrathin sections and transmission electron microscope,with the size of 20−60 nm,the number of more than 30 in each cell at average,which indicated that F.thermophilum can synthesize intracellular nanocrystals and also belongs to high-yield nanocrystals-producing strain.Intriguingly,the nanocrystals contain ferrite and cobalt characterized by EDS X-ray analysis,suggesting that both cobalt and ferrite are potentially contributed to the formation of nanocrystals.Moreover,under the different energy source culture conditions of FeSO4 and CuFeS2,the size and the morphology of the nanocrystals are different.It was also found that the higher initial Fe availability leads to an induced synthesis of larger nanocrystals and the lower oxidation-reduction potential(ORP)leads to an induced effect on the synthesis of nanocrystals with abnormal unhomogeneous size,which suggested that the higher initial Fe availability and the lower oxidation-reduction potential lead to a higher uptake efficiency of iron ions of F.thermophilum by iron and ORP gradient culture.

Role and maintenance of redox potential on chalcopyrite biohydrometallurgy:An overview

Chalcopyrite is one of the most important copper minerals;however,the extracted efficiency of chalcopyrite is still not satisfactory in hydrometallurgy owing to its high lattice energy which leads to its low dissolution kinetics.To overcome the difficulties,many advanced technologies have been developed,including the selection of high effectively bacteria,the inhibition of the passivation film adhered onto the minerals surface,and the maintenance of solution redox potential under an optimum range.Up to date,considerable researches on the first two terms have been summarized,while the overview of the last term has been rarely reported.Based on corresponding works in recent years,key trends and roles of solution redox potential in copper hydrometallurgy,including its definition,effect and maintenance,have been introduced in this review.

以游戏为工具对低龄外语学习者进行词汇教学

在过去的几十年里,对于少年儿童来说,学外语成为一种现象。英语已经成为幼儿园和小学的主要科目之一,甚至沿海城市还开设了其他语种课程。本文通过研究使用游戏来进行词汇教学的实际含义,提出了教师在运用游戏教学词汇时面临的挑战,希望能够为低龄外语教学中游戏的运用提供参考。