紫外可见分光光度法对EPS与金属离子的相互作用的研究

生物冶金技术是一种针对贫、杂、细矿石十分有效的方法,具有传统选冶方法不可比拟的优点。胞外聚合物（Extracellular Polymeric Substances,EPS）对生物冶金过程中的金属硫化矿的溶解有着非常重要的作用。通过紫外分光光度计对硫酸法和甲醛-NaOH法提取的EPS及其与金属离子的作用进行了分析,结果表明胞外聚合物仅与Fe³⁺发生了络合,从而验证了胞外聚合物是通过与其络合的Fe³⁺的氧化作用来溶解金属硫化矿物的。     

二氧化硫对闪锌矿可浮性影响的研究

在多金属硫化矿优先浮选中,近年来国內外选矿工作者对“无氰浮选”进行了大量研究。用二氧化硫代替氰化物是国內外所进行的研究工作之一。二氧化硫作为多金属硫化矿优先浮选中的调整剂在苏联、日本及加拿大得到了应用,国內某些选矿厂亦曾进行过试验研究。     

壳聚糖及其衍生物在硫化矿浮选分离中的 研究进展

浮选是硫化矿物分离最常用的方法,抑制剂对浮选分离效果具有决定性的作用。壳聚糖作为一种高 效环保的新型抑制剂,国内外学者对其在浮选中的应用进行了大量研究,针对这些研究,梳理了壳聚糖及其衍生物 在硫化矿分离方面的应用,总结了壳聚糖及其衍生物在矿物浮选时的作用机理,指出矿物的化学性质、壳聚糖及其 衍生物分子结构上基团以及溶液 pH 的不同,其作用效果和作用机理也不尽相同。壳聚糖对金属硫化矿的抑制主 要通过形成 M-NHn基团使抑制剂吸附在矿物表面使其亲水,而对石英、蛇纹石等硅酸盐矿物则是通过分子间作用 力物理吸附在矿物表面。壳聚糖改性生成的衍生物种类众多,在未来硫化矿的浮选分离研究中发展前景广阔,大 部分金属能够与其进行络合作用,在金属硫化矿的浮选分离方面具有很好的研究空间。     

微生物胞外聚合物在浸矿过程中作用的研究进展

综述国内外学者对浸矿微生物的胞外聚合物的研究进展.胞外聚合物是革兰氏阳性菌和革兰氏阴性菌细胞分泌的不同种类的生物聚合物,是生物膜中围绕在细菌周围的高度含水的多聚大分子.不同细菌的胞外聚合物组成和物理化学属性不同,决定着生物膜的粘附、构型及生物学特性.     

金属氢氧化物与捕收剂对黄铜矿浮选的影响

在浮选厂矿浆中,以氢氧化物形式沉淀的金属会影响复合矿石中硫化矿的可浮性。本文研究了在控制良好的分批浮选试验中,黄药对铅、锌氢氧化物与黄铜矿发生的相互作用的影响,研究中尤其注意了捕收剂在硫化矿浮选中的作用。所得的结论是,黄药有时具有既能提高硫化矿表面疏水性,又能抵消氢氧化物亲水作用的双重作用。黄药与金属氢氧化物互相作用的机理迄今尚未弄清,但这种作用与金属类型确实存在着关系。     

多金属硫化矿浮选研究的新进展

论述了近几年来国内外多金属硫化矿浮选的进展，介绍了包括多金属硫化矿浮选理论研究、浮选药剂研究和浮选工艺研究三个方面的现状及其发展。着重阐述了多金属硫化矿浮选新药剂的开发和运用。     

有色金属矿尾矿微生物浸出技术研究进展

在开发利用我国大量堆存的有色金属矿尾矿中的有价金属矿物,溶出有毒金属元素,实现资源的充分利用与减少污染方面,微生物浸出技术是一项最有前途的技术。为了系统展示微生物浸矿技术的进展,从直接浸矿、间接浸矿、原电池效应和胞外聚合物（EPS）作用等方面介绍了微生物浸矿的作用机理;从浸矿菌种和外界因素（包括温度、pH、氧化还原电位、营养物质）方面总结了影响浸矿效果的关键技术;并对尾矿预处理、诱变育种、使用催化剂等措施在强化浸出效果方面的作用进行了介绍,最后对微生物浸出技术在有色金属矿尾矿无害化和资源化处理方面的发展方向和前景进行了展望。     

复杂多金属硫化矿浮选新技术研究现状

介绍了复杂多金属硫化矿浮选新技术的研究现状,并对电化学浮选、细粒浮选、磁力浮选、生物浮选等新工艺和新技术进行了讨论和分析,指出开发高效浮选新技术仍是多金属共生硫化矿选矿研究的重点和发展方向。     

复杂多金属硫化矿浮选新技术研究现状

介绍了复杂多金属硫化矿浮选新技术的研究现状,并对电化学浮选、细粒浮选、磁力浮选、生物浮选等新工艺和新技术进行了讨论和分析,指出开发高效浮选新技术仍是多金属共生硫化矿选矿研究的重点和发展方向。     

复杂多金属硫化矿浮选新技术研究现状

介绍了复杂多金属硫化矿浮选新技术研究现状,并对电化学浮选、细粒浮选、磁力浮选、生物浮选等新工艺和新技术进行了讨论和分析,指出开发高效浮选新技术仍是多金属共生硫化矿选矿研究的重点和发展方向。     

Some quantitative data on bacterial attachment to pyrite

Bacterial attachment and biofilm formation are important for microbial bioleaching of metal sulfides, however, many details of the role played by bacteria are still unknown. Attachment as the first step in biofilm formation is critical. Our investigations are focused on these processes to control bacterial bioleaching processes.In moderately thermophilic pure cultures of Acidithiobacilluscaldus and Leptospirillumferriphilum, only the latter one showed significant attachment and biofilm formation to metal sulfides. In pure cultures of the mesophilic strains Acidithiobacillusspp., Leptospirillumferrooxidans, Ferrimicrobiumacidiphilum and a novel undescribed leaching organism designated SPIII/3, attachment was significant by L. ferrooxidans, At. thiooxidans and SPIII/3.In general, interaction of different species in mixed cultures resulted in increased attachment, increased production of extracellular polymeric substances (EPS) and leaching. Bacteria like Leptospirillumspp. enhanced the attachment of other species in mixed biofilms. Another finding is that large areas of the surface of minerals remain uncolonized, whereas at some places bacteria attach in clusters.Based on these findings we conclude that attachment and thereby bacterial leaching can be improved by the production of EPS by several strains especially in combination with Leptospirillumspp.     

Visualization of initial attachment of bioleaching bacteria using combined atomic force and epifluorescence microscopy

Bioleaching is the dissolution of metal sulfides, such as pyrite and chalcopyrite, by bacterial oxidation processes. It has been found that attachment of leaching bacteria to the mineral surface enhances the metal sulfide dissolution. The interaction of mixed cultures with respect to initial attachment processes has not been investigated. Therefore in this study we quantified and visualized initial colonization on pyrite by pure and mixed cultures. Strains of the genera Acidithiobacillus and Leptospirillum were tested. Sessile and planktonic cells were visualized by fluorescence microscopy using DAPI, FISH, Syto? 9, lectin- and calcofluor-staining. Additionally, atomic force microscopy (AFM) was used for the investigations on cell morphology, spatial arrangement of cells on pyrite and mineral surface topography. The morphology of planktonic and sessile cells is different. Moreover, planktonic cells show differences in morphology due to the use of different substrata. By using different visualization methods it could be proven that colonization and biofilm formation on pyrite in mixed cultures is mostly dominated by Leptospirillum spp. Interactions of different species resulted in increased production of extracellular polymeric substances (EPS) or caused bacteria showing little tendency to attach when in monoculture to be incorporated into a biofilm by those that attach preferentially. Consequently, biofilm formation and metabolic diversity were furthered. One of the most important results is the finding that not all bioleaching bacteria are involved to the same extent in biofilm formation. Thus, further work shall allow us elucidate the important bacteria for biotechnological use, thereby leaching processes can be faster, more efficient and costs can be reduced.     

基于InSAR技术和SA-SVR算法的矿区沉降预测模型

为了解决矿区沉降预测模型精度低、预测模型与实际开采情形不符的问题,提出了一种基于合成孔径雷达干涉测量（Synthetic Aperture Radar Interferometry,InSAR）技术、支持向量回归算法 （Support Vector Regression,SVR）以及模拟退火算法（Simulated Annealing,SA）相结合的新型矿区沉降预测模型。首先,以InSAR技术获取矿区沉降监测数据,对数据进行处理得到测试点的累计沉降量,并将 其与GPS实际测量结果进行比较,发现二者吻合性较好。然后,进行矿区沉降预测模型构建,通过SVR算法得到静态沉降预计模型,再利用SA算法得到模型中的参数最优取值。为了使预测数据符合矿区开采实际情况, 引入嵌入维数公式,得到矿区沉降预测动态模型及精度评价指标。最后,将构建的沉降动态模型应用于陕西省大柳塔矿区,得到预测值和实际监测值之间绝对误差的最大值为9 mm,相对误差的最大值为3%;模型评价 指标通过计算得到试验区平均绝对误差的最大值为2.5%,最小的相关性指数为0.8,表明该模型预测精度较高。     

Sequential precipitation of Cu and Fe using a three-stage sulfidogenic fluidized-bed reactor system

The exposure of sulfides, such as pyrite (FeS₂) to water and air leads to the formation of acidic metal and sulfate containing waters, generally referred to as acid mine drainage (AMD). Under anaerobic conditions and in the presence of a suitable electron and carbon source, sulfate-reducing bacteria (SRB) can reduce sulfate to hydrogen sulfide which can precipitate metals as low-solubility sulfides. In the present study, a three-stage fluidized-bed reactor (FBR) system was operated at 35 °C with ethanol as an electron and carbon source for SRB to sequentially precipitate Cu and Fe from synthetic AMD. The system consisted of two pre-settling tanks before a sulfidogenic FBR for the sequential precipitation of Cu and Fe with biogenic H₂S gas and HS⁻ containing effluent, respectively. Cu and Fe precipitation efficiencies were over 99% and sulfate and COD removals 60-90%. Biologically produced alkalinity increased the initial pH of the AMD from 3.0 to neutral values.     

Phase distribution identification in the column leaching of low grade ores using MRI

Heap bioleaching is gaining importance as an approach for the recovery of valuable metals (e.g. Cu²⁺) from low grade ores. In this process iron and/or sulfur oxidising microorganisms are used to aid the oxidation of base metal sulfides in the ore, thereby liberating the metal ions into solution. Leach performance is strongly influenced by the contacting of the leach solution and the ore particles. In order to better understand the distribution of the leaching solution on the pore scale in these heaps, Magnetic Resonance Imaging (MRI) was used to acquire images non-invasively of a section of an irrigated ore bed. This was made possible by the use of specialist MRI acquisition sequences suited to the magnetically heterogeneous environment as presented by the ore material. From the images we were able to determine the pore-occupancy of the liquid and gas phases and to provide novel measurement of the interfacial area between air, leach solution and ore.     

有色金属矿山选矿废水中硫化物的治理新途径

有色金属选矿厂的选矿废水中硫化物的处理是国内、外矿山废水治理的难题。本研究采用清洁生产审计法,从源头到末端对选矿作业全过程进行调查,将得到的数据、信息分析研究,建立起矿石、工业用水、硫化物的投入和产出平衡,从上述平衡中寻求硫化物时有超标的原因,从而有针对性地提出了分步综合治理硫化物的方案,与传统的一步到位的治理方案比较,具有较大的经济效益和环境效益。本方法亦可以推广到其他矿山应用,这对探索解决矿山废水中硫化物治理这一难题,在理论上和方法上均是一次有益的实践。     

生物冶金中混合菌的作用

生物冶金环境中的微生物是多样的,至今已经报道有13个属的细菌能够氧化浸出金属硫化物。细菌浸出金属硫化物有间接浸出、接触浸出和协作浸出3种作用机制,其中间接浸出又有硫代硫酸盐和多硫化物2种作用途径。在生物冶金过程中使用混合菌较使用单一菌有很多优势,但使用混合菌也有一些不利因素。混合菌的浸矿机制还不是很明确,因此,为了更好地利用生物冶金技术,应加强有关混合菌的研究,以便能控制混合菌的组成和活性,使生物浸出过程达到最优化。     

The ability of static secondary ion mass spectrometry to discriminate submonolayer from multilayer adsorption of thiol collectors

Experiments have been carried out to establish whether static time-of-flight secondary ion mass spectrometry (ToF-SIMS) alone is able to differentiate monolayer and multilayer coverage of thiol collectors on sulfide minerals. The systems investigated were those for which X-ray photoelectron spectroscopy is able to provide an independent determination of the extent of coverage, and included diethyldithiophosphate (DTP) and 2-mercaptobenzothiazole (MBT) on chalcocite, DTP on Ag_2+∂S, and iso-butyl xanthate (BX) and MBT on galena. For adsorption of a thiol collector (TC) on copper and silver sulfides, TC and metal(TC)H ions were detected for both monolayer and multilayer coverage. For multilayer coverage only, metal(TC)₂ ions were evident, notwithstanding the fact that other spectroscopic measurements had revealed the stoichiometry of the principal multilayer species to be metal(TC). For adsorption on galena, TC and metal(TC) ions were observed for both monolayer and multilayer coverage, whereas for multilayer coverage only, fragment ions from Pb(TC)₂ and (TC)₂ species were evident. Indeed, for all the systems studied, static ToF-SIMS was able to distinguish monolayer from multilayer coverage. However, differentiation was reliable only when both positive and negative secondary ion spectra were determined, and possible only because the multilayer species on copper and silver sulfides included a low concentration of metal dithiolate. In light of those findings, unequivocal differentiation by means of static SIMS is expected to be possible for all thiol collector/sulfide systems.