Microwave-Assisted Au and Ag Nanoparticle Synthesis: An Energy Phase-Space Projection Analysis

Microwave-assisted synthesis of gold and silver nanoparticles, as a function of Green Chemistry, non Green Chemistry, and four applicator types are reported. The applicator types are Domestic microwave ovens, commercial temperature controlled microwave chemistry ovens (TCMC), digesters, and axial field helical antennae. For each of these microwave applicators the process energy budget where estimated (Watts multiplied by process time = kJ) and energy density (applied energy divided by suspension volume = kJ·ml-1) range between 180 ± 176.8 kJ, and 79.5 ± 79 kJ·ml-1, respectively. The axial field helical field an-tenna applicator is found to be the most energy efficient (0.253 kJ·m-1 per kJ, at 36 W). Followed by microwave ovens (4.47 ± 3.9 kJ·ml-1 per 76.83 ± 39 kJ), and TCMC ovens (2.86 ± 2.3 kJ·m-1 per 343 ± 321.5 kJ). The digester applicators have the least energy efficiency (36.2 ± 50.7 kJ·m-1 per 1010 ± 620 kJ). A comparison with reconstructed ‘non-thermal’ microwave oven inactivation microorganism experiments yields a power-law signature of n = 0.846 (R2 = 0.7923) four orders of magnitude. The paper provides a discussion on the Au and Ag nanoparticle chemistry and bio-chemistry synthesis aspects of the microwave applicator energy datasets and variation within each dataset. The visual and analytical approach within the energy phase-space projection enables a nanoparticle synthesis route to be systematically characterized, and where changes to the synthesis are to be mapped and compared directly with historical datasets. In order to help identify lower cost nanoparticle synthesis, in addition to potentially reduce synthesis energy to routes informed changes to potentially reduce synthesis energy budget, along with nanoparticle morphology and yield.

Gold and antimony metallogenic relations and ore-forming process of Qinglong Sb(Au) deposit in Youjiang basin, SW China: Sulfide trace elements and sulfur isotopes

In the northwestern margin of the Youjiang basin(NWYB)in SW China,many Carlin-like gold deposits are highly antimony(Sb)-rich,and many vein-type Sb deposits contain much Au.These deposits have similar ages,host rocks,ore-forming temperatures,ore-related alterations and ore mineral assemblages,but the Au and Sb metallogenic relations and their ore-forming process remain enigmatic.Here we investigate the large Qinglong Sb deposit in the NWYB,which has extensive sub-economic Au mineralization,and present a new metallogenic model based on in-situ trace elements(EPMA and LA-ICP-MS)and sulfur isotopes(NanoSIMS and fs-LA-MC-ICPMS)of the ore sulfides.At Qinglong,economic Sb ores contain coarse-grained stibnite,jasperoid quartz and fluorite,whilst the sub-economic Au–Sb ores comprise dominantly veined quartz,arsenian pyrite and fine-grained stibnite.Three generations of ore-related pyrite(Py1,Py2 and Py3)and two generations of stibnite(Stb1 and Stb2)are identified based on their texture,chemistry,and sulfur isotopes.The pre-ore Py1 is characterized by the lower ore element(Au,As,Sb,Cu and Ag)contents(mostly below the LA-ICP-MS detection limit)and Co/Ni ratios(average 0.31)than the ore-stage pyrites(Py2 and Py3),implying a sedimentary/diagenetic origin.The Py2 and Py3 have elevated ore element abundance(maximum As=6500 ppm,Au=22 ppm,Sb=6300 ppm,Cu=951 ppm,Ag=77 ppm)and Co/Ni ratios(average 1.84),and have positive As vs.Au–Sb–Cu–Ag correlations.Early-ore Stb1 has lower As(0.12–0.30 wt.%)than late-ore Stb2(0.91–1.20 wt.%).These features show that the progressive As enrichment in ore sulfides is accompanied by increasing Au,Sb,Cu and Ag with the hydrothermal evolution,thereby making As a good proxy for Au.As-rich,As-poor and As-free zones are identified via NanoSIMS mapping of the Au-bearing pyrite.The As-rich zones in the Qinglong Au-bearing pyrites(Py2 and Py3)and ore stibnites(Stb1 and Stb2)have narrowδ^(34)SH_(2)S ranges(-8.9‰to +4.1‰,average-3.1‰)and-2.9‰to +6.9‰,average + 1.3‰),respectively,indicating that the Au-rich and Sb-rich fluids may have had the same sulfur source.Published in-situ sulfur isotopic data of pyrite As-rich zones from other Carlin-like Au deposits(Shuiyindong,Taipingdong,Nayang,Getang and Lianhuashan)in the NWYB have similar ore-fluidδSH_(2)S values(-4.5‰to +6.7‰,average-0.6‰)to those of Qinglong.Therefore,we infer that the sulfur of both Au and Sb mineralization was derived from the same magmatic-related source(0±5‰)in the NWYB.Moreover,the core of pyrites(Py1)has variable S isotope fractionation(-18.9‰to +18.1‰,mostly +3‰to +12‰),suggesting that the higher-^(34)S H_(2)S was produced by bacterial sulfate reduction(BSR).The hydrothermal pyrite(Py2 and Py3)δ^(34)S values gradually decrease with increasing As concentrations,and ultimately,within the restricted range(-5‰to +5‰)in As-rich zones.This variation implies that the As-rich pyrite was formed through ongoing interactions of the magmatic-hydrothermal fluid with pre-existing sedimentary pyrites,causing the progressive decreasing δ^(34)S values with As content increase,Hence,the fluid/mineral interaction may have generated the observed variation in δ^(34)S and As contents.Overall,comparing the Au and Sb deposits in the NWYB,we favor a magmatic-related source for the Au–Sb–As-rich fluids,but the Au-and Sb-ore fluids were likely evolved at separate stages in the ore-forming system.

Analysis of Aging Mechanism of SBS Polymer Modified Asphalt based on Fourier Transform Infrared Spectrum

The aging mechanism of SBS modified asphalt during its aging process was studied.The characterizations of base asphalt,SBS polymer and its modified asphalt were determined in different aging time by Fourier transform infrared spectrum（FTIR）.FTIR shows that oxidative dehydrogenation reaction occurs in asphalt,and unsaturated carbon bond is generated under short-term thermal aging condition.Additionally,SBS polymer was aged significantly under that condition,the speed of which was faster than that of base asphalt.The aging laws of both asphalt and SBS polymer during the aging process of SBS modified asphalt were similar to their aging laws respectively.Due to the protective effect between asphalt and SBS polymer,the aging degrees of asphalt and SBS polymer were lower than those aged independently.

Thermal Oxidative Aging Characterization of SBS Modified Asphalt

Both macro and micro-methods were introduced to study the physical and chemical properties of thermal oxidative aging of SBS （styrene-butadiene-styrene） modified asphalt. The physical properties of SBS modified asphalt before and after aging were analyzed by normal tests. The structure and quality variation of SBS modified asphalt during the aging process was analyzed by FTIR （Fourier transform infrared spectrum）. FTIR result shows that the degeneration of SBS modified asphalt is mainly caused by oxidative reaction and rupture of C=C double bond. The molecular weight variations of asphalt function groups and SBS polymer were studied by GPC （Gel Permeation Chromatography）. GPC result shows that small molecules transform into larger one in asphalt and SBS polymer molecule degrade during the aging process. SBS polymer may lose its modifying function after long time aging.

柴北缘滩间山金矿区Au-As-Sb地球化学异常组合及其外围找矿预测应用

Au-As-Sb地球化学异常组合在中低温热液型金矿床中常指示着矿体前缘晕相或中浅部矿体的出露,对剥蚀较弱的金矿床而言,该组合化探异常有利于指引造山型金矿床浅部金矿体的发现。不同于传统化探需测试数十个元素、处理上万个数据而圈定异常的惯例,在柴北缘成矿带滩间山金矿区及外围水系沉积物研究中,采用Au-As-Sb元素组合特征分析方法圈定多个Au-As-Sb地球化学异常组合,大幅提高了水系沉积物勘查的工作效率。同时,R型聚类分析表明Au、As、Sb元素之间相关性强,与已发现的青龙沟、金龙沟大型造山型金矿床地质特征、主成矿期自然金+黄铁矿+毒砂+(黄铜矿+方铅矿+闪锌矿)矿石矿物组合、造山型金矿床连续成矿模型Au、As、Sb纵向变化规律等特点基本一致,表明该地区矿床赋存深度处于中浅成,预示着该矿床外围和深部具有较好找矿前景。

贵州开阳磷矿地区下寒武统牛蹄塘组地层层序及其As、Sb、Au、Ag丰度异常与赋存状态研究

贵州开阳磷矿地区出露较为完整的下寒武统黑色岩系层序,这套黑色岩系中富含多种金属元素,但目前对岩系中主要低温成矿元素As、Sb、Au、Ag的地球化学背景异常与分布规律了解极少,对其形成背景与赋存状态无法进行深入讨论。本文以开阳磷矿地区下寒武统牛蹄塘组黑色岩系剖面作为研究对象,通过详细的野外地质调查、系统采样并进行地球化学分析、全岩硫同位素分析及黄铁矿电子探针分析,划分了详细的牛蹄塘组地层层序,对主要低温成矿元素(As、Sb、Au、Ag)的丰度异常、富集特征及赋存状态进行了研究,结果表明,黑色岩系中普遍富集As、Sb、Ag三种主要低温成矿元素,Au也在大部分层位富集。四种元素具有层控性的特点,在牛蹄塘组下部有机质含量较高的黑色白云质粉砂质页岩和黑色页岩层位中具有较高的元素丰度异常,在泥岩和粉砂岩混合层位元素丰度异常较低,钙质成分含量较高的层位元素含量较低。黄铁矿是黑色页岩中金的主要赋存矿物,也是Sb的重要赋存矿物,同时是Ag和As的次要赋存矿物;不同类型的黄铁矿,元素富集规律也不相同:As、Ag更容易富集在不规则集合体和草莓状黄铁矿中,Sb和Au则在散布的单颗粒黄铁矿中富集系数最高。

黑龙江省滨东地区Cu-Pb-Zn-W-As-Sb-Bi-Au-Ag地球化学块体矿产资源潜力预测

黑龙江省滨东地区是著名的铜铅锌钼成矿带.以金属活动态测量法进行的超低密度地球化学调查圈定的滨东地球化学块体为基础,运用成矿可利用金属量定量评价模型与方法对该块体的Au、Ag、Pb、W等矿产资源潜力进行了预测,预测结果远远大于该区已发现矿床的总储量,说明预测结果是合理的.预测结果对进一步开展矿产勘查工作具有参考和指导作用.

Space-selective Precipitation and Dissolution of Ag and Au Nanoparticles in Silicate Glasses by Femtosecond Laser Irradiation

In Ag^＋ and Au^3＋ co-doped silicate glass sample, we realized controllable precipitation and dissolution of Ag and Au nanoparticles. A new method was proposed for separate precipitation of Ag and Au nanoparticles in different areas of the same sample through femtosecond laser irradiation and further annealing; different colors were obtained in the same glass. We also studied the laser dissolution of Ag and Au nanoparticles in the Ag^＋ and Au^3＋co-doped silicate glass. The mechanism of the phenomena we observed was discussed briefly.

Au和Ag修饰TNTAs阵列及光电催化甘油转化研究

通过阳极氧化法制备TiO_(2)纳米管阵列(TNTAs),管径是60 nm和管长是5.4μm。进一步利用电沉积法制备了Au和Ag修饰的TNTAs/Au和TNTAs/Ag纳米管阵列。评价了负载不同Au和Ag含量对光阳极光电催化转化甘油耦合产氢耦合的影响。结果表明,负载Au和Ag的TNTAs可将甘油光电催化转化为甘油醛(GLD)、二羟基丙酮(DHA)等高附加值产品并协同产氢。TNTAs/Au(0.08 mmol/L)和TNTAs/Ag(0.04 mmol/L)的催化性能最高,其产氢速率分别为213.8,198.1μmol•cm^(-2)•h^(-1),甘油转化率为4.6%、4.4%,DHA的选择性为15.4%、15.3%。样品的最佳性能归功于金属纳米颗粒的等离子共振效应,即金属作为电子陷阱有效地聚集了光激发的电子,TiO_(2)导带中的电子被转移到金属上,防止了光生电子-空穴对的复合,有效地提高了TiO_(2)纳米管阵列的催化性能。

Organic Gases in Fluid Inclusions of Ore Minerals and Their Constraints on Ore Genesis:A Case Study of the Changkeng Au-Ag Deposit,Guangdong,China

The newly discovered Changkeng Au-Ag deposit is a new type of sediment-hostedprecious metal deposit. Most of the previous researchers believed that the deposit was formed bymeteoric water convection. By using a high vacuum quadrupole gas mass spectrometric system, ninelight hydrocarbons have been recognized in the fluid inclusions in ore minerals collected from theChangkeng deposit. The hydrocarbons are composed mainly of saturated alkanes C_(1-4) and unsaturatedalkenes C_(2-4) and aromatic hydrocarbons, in which the alkanes are predominant, while the contentsof alkenes and aromatic hydrocarbons are very low. The sum alka/sum alke ratio of most samples ishigher than 100, suggesting that those hydrocarbons are mainly generated by pyrolysis of kerogens insedimentary rocks caused by water-rock interactions at medium-low temperatures, and themetallogenic processes might have not been affected by magmatic activity. A thermodynamiccalculation shows that the light hydrocarbons have reached chemical equilibrium at temperatureshigher than 200 deg C, and they may have been generated in the deep part of sedimentary basins(e.g., the Sanzhou basin) and then be transported by ore-forming fluids to a shallow position of thebasin via a long distance. Most of the organic gases are generated by pyrolysis of the type IIkerogens (kukersite) in sedimentary host rocks, only a few by microorganism activity. Thecompositions and various parameters of light hydrocarbons in gold ores are quite similar to those insilver ores, suggesting that the gold and silver ores may have similar metallogenic processes.Based on the compositions of organic gases in fluid inclusions, the authors infer that the Changkengdeposit may be of a tectonic setting of continental rift. The results of this study support fromone aspect the authors' opinion that the Changkeng deposit is not formed by meteoric waterconvection, and that its genesis has a close relationship with the evolution of the Sanzhou basin,so it belongs to the sedimentary hot brine transformed deposit.

Classification, Tectonic Setting, and Mineralization Potential of Ayetoro and Sasaro Syenitic Plutons in Igarra Schist Belt, Southwestern Nigeria

Petrographic and geochemical studies of syenite-looking Ayetoro and Sasaro plutons within Igarra Schist Belt were carried out in order to classify them and determine their tectonic setting and mineralization potential. Petrographic study and geochemical classification revealed that while Ayetoro boss is microgranite constituting an aggregate of medium grained muscovite, quartz and biotite minerals, Sasaro stock is micromonzonite made up of medium grained albite, orthoclase, biotite, hornblende and pyroxene. Geotectonic setting showed the boss and stock are orogenic, probably derived from the same upper mantle magma as Igarra batholith that got contaminated by crustal materials responsible for their difference in lithology. Their mineralization potential showed that the massive Ayetoro microgranite with no appreciable trace-element contents cannot serve as host of any metallic deposit, and should be suitable for industrial applications. Whereas, the silicified, highly sheared Sasaro monzonite, with elevated level of some trace elements contents as Ag, Au and Cu, could harbor Ag-Au-Cu deposit.

ICP-AES法测定纯铜中的Bi,Sb,As,Fe,Ni,Pb,Sn,Zn,Ag的方法

研究了ICP-AES法测定纯铜中的Bi,Sb,As,Fe,Ni,Pb,Sn、Zn和Ag等9个元素的分析方法。进行了基体元素铜对9个分析元素的光谱干扰研究,选择了合适的分析谱线,同时测定了分析方法的检出限。

Light Hydrocarbons in Fluid Inclusions and Their Constraints on Ore Genesis:A Case Study of the Songxi Ag(Sb)Deposit,Eastern Guangdong,China

The Songxi deposit is a newly discovered large Ag (Sb) deposit. By using a suite of high-vacuum quadrupole gas mass spectrometer systems, the authors have recognized many kinds of light hydrocarbons in fluid inclusions of minerals. These hydrocarbons are mainly composed of C1-C4 saturated alkanes, while the contents of C2-C4 unsaturated alkenes and aromatic hydrocarbons are quite low, suggesting that the metallogenic processes have not been affected by magmatic activities. Chemical equilibrium studies show that these hydrocarbons may be a mixture of organic gases generated by microorganism activity and those by thermal cracking of type-n kerogens (kukersite) in sedimentary host rocks, and the former may constitute more than two-thirds, implying that microorganism might have played an important role in the metallogenesis. The equilibrium temperature of the latter is about 300℃, which is much higher than the geothermal temperature at the estimated depth of metallogenesis. Thus, the light hydrocarbons generated by thermal cracking of kerogens probably originated in the deep part of the sedimentary basins and then migrated through a long distance to shallower horizons of the basin. Based on the composition of light hydrocarbons in fluid inclusions, the authors infer that the Songxi deposit was formed in a continental rift. The analytical data presented in this paper support from one aspect the genetic model that the Songxi deposit may be a sedimentary hot brine transformed deposit instead of a submarine basic volcanic exhalation and low-medium temperature volcanic hydrothermal fluid filling deposit proposed by most previous researchers.

Geochemistry and geochronology of Late Jurassic and Early Cretaceous intrusions related to some Au(Sb) deposits in southern Anhui: a case study and review

Some Au deposits in southern Anhui Province have recently been found to be closely associated with Late Mesozoic intrusions. Typical examples include the Huashan Au(Sb) deposit and Au deposits at Zhaojialing, Wuxi,and Liaojia. In order to understand the mechanisms that led the formation of these Au deposits, we make detailed reviews on the geological characteristics of these Au deposits. Specifically, we present new LA-ICP-MS zircon U–Pb dating, along with elemental and Hf isotopic data from the Huashan Au(Sb) deposit. Our data suggests that the Huashan ore-related intrusions were emplaced during the Late Jurassic and Early Cretaceous periods(144–148 Ma). They are characterized by arc-magma features and high oxygen fugacity and are rich in inherited zircons. Zircon U–Pb ages and Lu–Hf isotopes from intrusions suggest that Proterozoic juvenile lithosphere is the main source of these intrusions. The regional geological history implies that lithosphere beneath southern Anhui was produced during a Proterozoic subduction and was fertilized with Au(Cu) in the process. Integrated with theresults of previous studies, we inferred that Late Mesozoic intrusions formed by the remelting of the lithosphere could provide the metal endowment for the Au-rich deposits in southern Anhui.

扬子地块西南缘低温成矿域Au、Sb、Hg、As矿床区域分布上的共生分异及控制因素

扬子地块西南缘大面积低温成矿域的Au、Sb、Hg、As矿床,常出现共生分异的现象,在空间上形成Au、Sb、Hg、As矿床、矿带相伴出现而又相对独立的规律性分布。在详细研究Au、Sb、Hg、As矿床、矿带区域分布及其产出地质背景的基础上,从不同的角度,对制约Au、Sb、Hg、As矿床、矿带共生分异的因素进行了探讨。

Outdoor aging of road asphalt and SBS modified asphalt

The process of performance degradation of road asphalt(RA)is regarded as aging.At present,better understanding of the thermal-oxidative aging of asphalt is achieved and the corresponding method to evaluate this process is developed;meanwhile,photo-oxidative aging(aging in an atmospheric environment,which is referred to as“outdoor aging”in this paper)of asphalt remains at the initial stages of scientific exploration.The outdoor natural ultraviolet(UV)aging of RA and SBS modified asphalt(SBSMA)are investigated in this study.The experimental results show that the basic performances of RA and SBSMA present similar change tendencies.The softening point increased,while the penetration and ductility decreased as the outdoor aging time passed by,and the 5℃ ductility(ductility measured at 5℃)of SBSMA decreased very quickly.The group components of RA and SBSMA also change during UV aging.The content of asphaltene rose and that of aromatics and saturates decreased,while the content of resins changed insignificantly.Moreover,the Fourier transform infrared(FTIR)graphs show that the content of sulfoxide and carbonyl groups in RA and SBSMA increased significantly during the outdoor aging process.

滇东南地区Au-As-Sb-Hg地球化学异常及金矿地质条件

滇东南地区金矿床(点)及Au、As、Sb、Hg元素异常空间分布,受区域深大断裂、次级背斜、次级断裂构造控制明显。在此基础上初步总结了金矿成矿以背斜+断裂+有利岩性界面的有利地质条件。

Evaluation on Soil Heavy Metal Pollution around Tailing Areas: A Case Study of Ag-Sb Deposit in Northeastern Guangdong

In October 2012,an evaluation using potential ecological hazard risk index was carried out on soil heavy metal pollution around AgSb deposit tailing areas in northeastern Guangdong. Results indicate that( i) soil heavy metal pollution is mainly Cd-Ni compound pollution,including Cd content 0. 31- 2. 66 mg / kg( average content is 1. 11 mg / kg),the situation of exceeding standard is serious( the rate of exceeding standard is 100%); the total potential ecological hazard risk index( RI) is between 50 and 300,and it is moderate pollution;( ii) in soil heavy metal content,only Ni and Cu are positively correlated. Since there is certain degree of Ni pollution in this deposit,the synergetic effect of Cu and Ni may deteriorate Ni pollution.

Study of Corrosion Resistance of Laser Welded Au-Pd-Ag-In Alloy Using Electrochemical Techniques

The aim of this work was to evaluate the corrosion resistance of AuPdAgIn alloy, submitted to laser beam welding, in 0.9% NaCl solution, using electrochemical techniques. Measures of the open circuit potential (OCP) versus time were applied to electrochemical experiments, as well as potentiodynamic direct scanning (PDS) and electrochemical impedance spectroscopy (EIS) on AuPdAgIn alloy, submitted to laser beam welding in 0.9% NaCl solution. Some differences observed in the microstructure can explain the results obtained for corrosion potential, Ecorr, and corrosion resistance, Rp. EIS spectra have been characterized by distorted capacitive components, presenting linear impedance at low frequencies, including a non-uniform diffusion. The area of the laser weld presented corrosion potential slightly superior when compared to the one of the base metal. The impedance results suggest the best resistant corrosion behavior for laser weld than base metal region. This welding process is a promising alternative to dental prostheses casting.