Accelerating the decarbonization of carbonaceous gold ore by suspension oxidation roasting towards the improvement of gold leaching efficiency

Eliminating the gold preg-robbing effect of carbonaceous matter in carbonaceous gold ores is crucial for gold leaching. In this study, suspension oxidation roasting was proposed to accelerate the decarbonization of carbonaceous gold ore. The characteristics of oxidation reaction process and gas release were analyzed by TG-DTA-FTIR. The phase transformation and microstructure evolution of samples during roasting were analyzed by XRD, SEM and BET. The results show that the gold preg-robbing effect was eliminated after the gasification of carbonaceous matter, and the CaO generated by decomposition of carbonates can effectively capture the SO₂. After roasting for 75 min at 650 °C in a 20% O₂ atmosphere, the total carbon removal rate reached 99.42%, the distribution of exposed gold increased from 28.85% to 77.10% and the gold leaching efficiency increased from 4.55% to 84.83%. In addition, about 70% sulfur was mainly fixed in the roasted products in the form of sulfate. Therefore, the suspension oxidation roasting process is an efficient and clean pretreatment method for carbonaceous gold ores.     

Emerging Plasmonic Assemblies Triggered by DNA for Biomedical Applications

Plasmonic gold nanocrystal represents plasmonic metal nanomaterials, and has a variety of unique and beneficial properties, such as optical signal enhancement, catalytic activity, and photothermal properties tuned by local temperature, which are useful in physical, chemical, and biological applications. In addition, the inherent properties of predictable programmability, sequence specificity, and structural plasticity provide DNA nanostructures with precise controllability, spatial addressability, and targeting recognition, serving as ideal ligands to link or position building blocks during the self-assembly process. Self-assembly is a common technique for the organization of prefabricated and discrete nanoparticle blocks for the construction of extremely sophisticated nanocomposites. To this end, the integration of DNA nanotechnology with Au nanomaterials, followed by assembly of DNA-functionalized Au nanomaterials can form novel functional Au nanomaterials that are difficult to obtain through conventional methods. Here, recent progress in DNA-assembled Au nanostructures of various shapes is summarized, and their functions are discussed. The fabrication strategies that employ DNA for the self-assembly of Au nanostructures, including dimers, tetramers, satellites, nanochains, and other nanostructures with more complex geometric configurations are first described. Then, the characteristic optical properties and applications of biosensing, bioimaging, drug delivery, and therapy are discussed. Finally, the remaining challenges and prospects are elucidated.     

四川某低品位金矿非氰浸出试验研究

对金品位为1.55 g/t的氧化矿采用非氰药剂进行浸金的工艺流程,考察了磨矿细度、药剂DZC浓度和浸出时间对金浸出率的影响。确定该金矿适宜的非氰浸出条件:磨矿细度-74μm含量占69.90%、石灰用量4 000g/t、矿浆液固比为2∶1、浸出药剂DZC浓度0.08%、浸出时间8 h,可获得金的浸出率为93.33%的良好指标。表明该氧化金矿在常温常压下,采用非氰浸出工艺是可行的。     

基于MOOC技术的在线金课建设策略

金课是对网络在线M O O C 教育的继承和发展，不仅注重对学生专业理论知识的讲解，更强调对学生高级思维意 识、知识转化为实践能力的培养，具有创新性、高阶性、挑战性等特征。围绕在线金课课程的建设，从课程教学情境、知识结构 体系、教学内容、交互模式等方面入手，进行网络化精品金课的组织与设计，满足广大学生群体多样化的专业课程学习需求。     

胶体金免疫层析法定量检测鱼和虾中苯巴比妥残留

建立了一种快速定量检测水产品鱼和虾中苯巴比妥残留的胶体金免疫层析方法。采用胶体金纳米粒标记苯巴比妥单克隆抗体,研究了胶体金免疫层析条件如标记体系p H值、标记抗体浓度、检测T线包被原浓度、质控C线羊抗鼠Ig G浓度、样品前处理方法等对胶体金灵敏度的影响,并借助胶体金试纸条读数仪进行定量检测。结果表明:方法检出限为0.07 ng/mL,线性范围0.08～0.94ng/m L,裸眼消线值(cut-off值)为10.0 ng/mL。方法特异性良好,与巴比妥、戊巴比妥、异戊巴比妥三种结构类似物交叉反应率小于10%。选择罗非鱼、草鱼、鲈鱼和虾进行添加回收试验,样品回收率在73.50%～114.17%之间,相对标准偏差小于15%,且结果与UPLC-MS/MS法一致。该方法具有准确、灵敏、简便、快速等特点,非常适用于水产品鱼和虾中苯巴比妥残留现场快速筛查。     

Easy access to pharmaceutically relevant heterocycles by catalytic reactions involving α-imino gold carbene intermediates

This review summarizes recent advances in the field of gold-catalyzed synthesis of pharmaceutically relevant aza-heterocycles via in situ generated α-imino gold carbene complexes as intermediates.     

福建某低品位金矿新型浸金剂浸金试验

福建某斑岩型金矿品位低、规模大,金主要以自然金形式存在,可见金的粒度较粗,为高效利用该低品位金矿,开展新型浸金剂金蝉全泥浸出试验和柱浸试验,结果表明：全泥浸出在磨矿细度为-0.074 mm占80%、矿浆浓度25%、加石灰调pH 值11.0左右、初始金蝉浓度为500 mg/L和过程中控制金蝉浓度不小于300 mg/L条件下浸出20 h,金的浸出率为93.43%,金蝉耗量为1.02 kg/t；柱浸在矿石粒度为-30 mm条件下喷淋浸出23天,金累计浸出率和金蝉累计耗量分别为86.54%和1.22 kg/t。     

安徽某铜铅锌多金属矿中伴生金银的赋存状态研究

利用光学显微镜、X-射线衍射分析、扫描电镜、矿物自动分析仪(MLA)及X-射线能谱分析,结合化学分析及化学物相分析等综合手段,研究了安徽某铜铅锌多金属矿中金银的赋存状态及工艺特性。结果表明,金主要分布在银金矿中,分布率为76. 53%;银主要分布在碲银矿中,分布率为70. 46%。影响金银回收的主要因素是金银矿物与黄铁矿关系密切,分别有43. 52%的金和19. 32%的银以黄铁矿包裹体的形式存在,由于金银矿物嵌布粒度较细,其中20μm以下的金矿物和银矿物分别占46. 54%和83. 65%,因此这部分金银主要损失到硫精矿中。     

基于正交设计的某矿超细全尾砂膏体材料配比试验研究

针对我国膏体充填的技术现状,结合某铁矿的生产实践情况,以超细全尾砂、废石与水泥混合制成膏体,运用正交设计的试验方法确定了各影响因素对超细全尾砂膏体各性能指标的影响程度。结果表明:由于超细尾砂的强吸水性,质量浓度对控制膏体塌落度具有主导的控制作用;对于充填体的前期强度(3 d和7 d),抗压强度的影响程度从大到小依次为质量浓度、灰砂比、尾废比,而对于后期强度(28 d)来说,其影响程度从大到小依次为灰砂比、尾废比、质量浓度;确定质量浓度为78%,尾废比为9∶2,灰砂比为1∶25时,膏体的各项性能指标均能达到实际生产和成本控制的要求。此研究可以为同类型的铁矿膏体充填提供一定的理论与技术支持。     

The Photomontage Activity of Postmodernism

For decades now, Douglas Crimp’s landmark 1980 essay ‘The Photographic Activity of Postmodernism’ has shaped our understanding of modernism’s aftermath, at least as it unfolded in North America and Western Europe. Less remembered, however, is the degree to which the procedures of disjunction, copying, appropriation, and outright theft that he highlighted were epitomised not just by contemporary photography, but by photomontage in particular. This article recovers the debates that led critics such as Crimp, Abigail Solomon-Godeau, Christopher Phillips, Benjamin Buchloh and others to turn to photomontage as one of their principal objects of concern in what became known as the postmodern critique of photography. Why was montage tasked to perform this critical function, particularly by people around the journal October who had not otherwise devoted the balance of their writing to photography’s history? The article suggests that these men and women, along with the contemporary artists they foregrounded, manifested what Mary Anne Doane has called a ‘desire for signification’, a reaction in the late 1970s against the mute theatricality of minimalist and conceptual art. Photomontage reintroduced representation to contemporary art and to the canon of art history. But unlike the reemerging illusionism in painting that also manifested this desire, montage guarded against an uncomplicated realism by highlighting and critiquing operations of representation in a manner that painting no longer could.