Surface reconstruction of Se-doped NiS_(2) enables high-efficiency oxygen evolution reaction

Surface reconstruction of electrocatalysts has been widely witnessed during the electrochemical processes.Here,NiS_(2),NiSe_(2), and Se doped NiS_(2)(Se-NiS_(2)) are fabricated for oxygen evolution reaction(OER) through a mild sulfuration and/or selenylation process of Ni(OH)_(2) supported on carbon cloth(CC).Through careful in-situ Raman spectroscopy and ex-situ X-ray photoelectron spectroscopy,surface reconstruction of NiS_(2),NiSe_(2),and Se-NiS_(2) during the OER process has been revealed.A potentialdependent study shows that Se-NiS_(2) undergoes surface evolution at lower potentials and requires the lowest potential for conversion to NiOOH as a highly OER-active species,accompanied by the leaching of SO_(4)^(2-) and SeO_(4)^(2-) that can again be adsorbed on the catalyst surface to enhance the catalytic activity.Density functional theory(DFT) calculations confirm that Se-NiS_(2) is more susceptible to surface oxidation through the OER process.Therefore,Se-NiS_(2) exhibits outstanding OER activity and stability in alkaline conditions,requiring an overpotential of 343 mV at a current density of 50 mA cm^(-2).A novel insight is provided by our work in understanding the surface reconstruction and electrocatalytic mechanism of Ni-based chalcogenides.

Factors influencing in-situ leaching of uranium mining in a sandstone deposit in Shihongtan, Northwest China

The Shihongtan uranium deposit in northwest China is a sandstone-type deposit suitable for alkaline in-situ leaching exploitation of uranium. Alkaline leaching tends to result in CaCO3 precipitation there by affecting the porosity of the ore-bearing aquifer. CaCO3 deposits can also block pumping and injection holes if the formulation parameters of the leaching solution are not well controlled. However, controlling these parameters to operate the in-situ leaching process is challenging. Our study demonstrates that the dissolved uranium concentration in the leaching solution increases as HCO3-concentration increases. Therefore, the most suitable HCO3-concentration to use as leaching solution is defined by the boundary value of the HCO3-concentration that controls CaCO3 dissolution-precipitation. That is, the dissolution and precipitation of calcite is closely related to pH, Ca2+ and HCO3-concentration. The pH and Ca2+ concentration are the main factors limiting HCO3-concentration in the leaching solution. The higher the pH and Ca2+ concentration, the lower the boundary value of HCO3-concentration, and therefore the more unfavorable to in-situ leaching of uranium.

Quantifying the impact of mineralogical heterogeneity on reactive transport modeling of CO_(2)+O_(2) in-situ leaching of uranium

CO_(2)+O_(2) in-situ leaching(ISL)of sandstonetype uranium ore represents the third generation of solution mining in China.In this study,reactive transport modeling of the interaction between hydrodynamic and geochemical reactions is performed to enable better prediction and regulation of the CO_(2)+O_(2) in-situ leaching process of uranium.Geochemical reactions between mining solutions and rock,and the kinetic uranium dissolution controlled by O_(2)(aq)and bicarbonate(HCO_(3)-)are considered in the CO_(2)+O_(2) ISL reactive transport model of a typical sandstone-hosted uranium ore deposit in northern China.The reactive leaching of uranium is most sensitive to the spatial distribution of the mineralogical properties of the uranium deposit.Stochastic geostatistical models are used to represent the uncertainty on the spatial distribution of mineral grades.A Monte Carlo analysis was also performed to simulate the uranium production variability over an entire set of geostatistical realizations.The ISL stochastic simulation performed with the selected geostatistical realizations approximates the uranium production variability well.The simulation results of the ISL reactive transport model show that the extent of the uranium plume is highly dependent on mineralogical heterogeneity.The uncertainty analysis suggests the effect of uranium grade heterogeneity was found to be important to improve the accurate capture of the uncertainty.This study provides guidance for the accurate simulation and dynamic regulation of the CO_(2)+O_(2) leaching process of uranium at the scale of large mining areas.

Studies on the Construction Parameter of an Artificial Occluded Cell for In-situ Inspection of the Propagation Rate of Localized Corrosion

An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate. In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism. The localized corrosion current density was dependent on the area ratio R of the cathode to the occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.

Enhancing the electrocatalytic performance of nitrate reduction to ammonia by in-situ nitrogen leaching

Electrochemical nitrate reduction reaction (NITRR) is regarded as a “two birds-one stone” method for the treatment of nitrate contaminant in polluted water and the synthesis of valuable ammonia, which is retarded by the lack of highly reactive and selective electrocatalysts .Herein, for the first time, nickel foam supported Co_(4) N was designed as a high-performance NITRR catalyst by an in-situ nonmetal leaching-induced strategy.At the optimal potential, the Co_(4) N/NF catalyst achieves ultra-high Faraday efficiency and NH_(3) selectivity of 95.4% and 99.4%, respectively.Ex situ X-ray absorption spectroscopy (XAS), together with other experiments powerfully reveal that the nitrogen vacancies produced by nitrogen leaching are stable and play a key role in boosting nitrate reduction to ammonia.Theoretical calculations confirm that Co_(4) N with abundant nitrogen vacancies can optimize the adsorption energies of NO_(3)^(-) and intermediates, lower the free energy (Δ G ) of the potential-determining step (*NH_(3) to NH_(3) ) and inhibit the formation of N-containing byproducts.In addition, we also conclude that the nitrogen vacancies can stabilize the adsorbed hydrogen, making H_(2) quite difficult to produce, and lowering ΔG from *NO to *NOH, which facilitates the selective reduction of nitrate.This study reveals significant insights about the in-situ nonmetal leaching to enhance the NITRR activity.

某砂岩型铀矿床地浸工艺钻孔施工效率分析

地浸采铀技术是中国砂岩型铀矿开采所使用的重要技术。地浸工艺钻孔是地面连通地下矿层的唯一通道,在地浸采铀中发挥着重要作用,其施工效率影响整个铀矿山的建设和发展。以某铀矿山为研究对象,统计分析了2019—2020年地浸工艺钻孔施工效率及存在的问题。结果表明,与岩芯钻机相比,水井钻机在施工中优势明显;泥浆泵配置、钻孔深度、后勤管理和保障均对钻孔施工效率有影响。对施工效率的影响因素提出了相应改进建议,以达到降本增效的目的。

原地浸矿注液孔施工设备钻机FMECA分析

原地浸矿是一种满足资源和环境保护要求的绿色生产工艺,常用于南方离子型稀土矿山的开采。开采前,需要在山体顶部进行注液孔的施工布置,而钻机是完成这项工作的重要机械设备。由于矿山环境恶劣,设备在使用过程中容易出现腐蚀、变形甚至断裂等故障,会降低稀土矿山的开采效率。基于此,运用故障模式影响与危害性分析(Failure Mode,Effects and Criticality Analysis,FMECA)技术,分析设备各种故障模式及主要影响,为设计、工艺、生产等部门持续性改进设备提供参考,提高设备的安全性和可靠性,延长其使用寿命。

地浸采铀技术标准体系构建研究

为了不断提高科研和管理水平,促进地浸采铀行业标准化水平,更科学和有效地开发和建设地浸铀矿山,重点梳理和分析了国内地浸采铀相关标准和技术规程的应用现状和应用存在的问题,并编制了地浸采铀技术标准体系表。

Evaluating the fractionation of ion-adsorption rare earths for in-situ leaching and metallogenic mechanism

The fractionation of ion adsorption rare earths(IAREs) along the depth in a shaft of a deposit at Dajishan,Jiangxi, China was comparatively evaluated using the partition values(PVs) and relative fractionation values(RFVs) of the leached rare earths(REs). It is found that both PVs and RFVs can objectively reflect the migration and fractionation of REs, but RE content and abrasion pH could not. However, the RFVs can provide more information to quantitatively evaluating the migration and fractionation characteristics of REs along the selected direction and region than PVs could, which is of significance for designing the optimal procedures of in-situ leaching based on the determined flow direction of injecting solution. It is demonstrated that the migration of Ce, Pr, and Nd along the depth direction is inert, and that of REs post Sm and Y is active. Meanwhile, the migration of La shows region characteristics which is active in the upper and inert in lower region. More interesting, the dependence of RFVs on atomic number of REs displays a tetrad group variation trend. However, the fractionation of REs among clay minerals with different particle sizes is not evident, especially for the clay in the bottom region. These results indicate that the migration and fractionation of REs not only are dominated by the adsorption of their hydrated ions, but also rely on their hydrolysis tendency, which provide information for understanding the metallogenic mechanism of IAREs.

建筑垃圾重金属浸出特性及环境污染风险研究进展

调研了我国部分地区建筑垃圾中的重金属浓度含量,如Cd、Ni、Pb的浸出浓度范围分别为0.03~0.51,8.12~21.26,40.12~95.10 mg/kg;总结影响建筑垃圾重金属浸出浓度主要因素,如pH值、液固比、粒径大小等,并阐述了建筑垃圾在实际工程中应用途径;对我国典型地区的建筑垃圾重金属进行生态风险评价。潜在生态风险评估结果指出,研究区均为轻度生态风险,其中商丘地区Hg单项潜在生态危险指数73.35,成都和北京地区Cd单项潜在生态危险指数分别为90.91和100.84,是生态风险贡献最大的污染元素;内梅罗综合污染指数评价法与地累积污染指数法结果一致,商丘和西安处于轻度污染水平,北京和成都处于中度污染水平,主要污染因子为Pb、Cd,总体而言建筑垃圾重金属浸出风险与区域特征有较大的相关关系。

废弃混凝土中重金属浸出性研究

以我国现有废弃混凝土为原料,研究废弃混凝土中重金属含量,采用模拟德国水槽试验法,以不同粒径、不同pH值、不同重金属元素(Cd、Cr、Cu、Ni、Pb、Zn)为影响因素,研究废弃混凝土中重金属离子的浸出性,结果表明,废弃混凝土中不同重金属含量不同,以Zn含量最高,Cr含量最低;粒径在1 mm以上时随着粒径增加重金属浸出性减小,在0.15 mm以下时,粒径无明显影响;随着浸出液pH值的减小,废弃混凝土中重金属离子的浸出量不同程度的增加,粒径大于1 mm时这种效果更明显;不同重金属浸出性不同,Pb和Zn易浸出,总体表现为Zn>Pb>Cu>Cd>Cr≈Ni。

基于人工湿地的组合处理系统净化校园人工湖设计

对成都某高校人工湖现状进行调研,并对目前国内外人工湖、景观水的水处理方法进行了比较,结合校园人工湖具体情况,采用"动力循环+砂滤+跌水充氧+人工湿地+湖体"生态组合处理系统进行校园人工湖的净化,并加装二氧化氯发生器用于藻类多发期的除藻,运行效果良好。

地浸采铀工艺钻孔施工与成建井技术现状及改进建议

地浸法采铀是铀矿开采的重要方法,地浸工艺钻孔作为溶浸液进入与抽出矿层的通道,在地浸采铀工艺过程中发挥着重要作用。文章介绍了国内地浸采铀工艺钻孔施工与成建井技术现状,针对存在问题,对钻探设备、钻进工艺和成井工艺提出了改进建议。

高含泥氧化铜矿石分粒级筑堆技术及其应用

高含泥氧化矿石浸堆因渗透性差而影响堆浸的正常进行。渗透试验表明,高含泥氧化矿石矿堆的渗透性与矿石粒级组成密切相关,采取矿石堆浸粒级划分:-1 mm为泥质物,+5 mm为块状矿,5～1 mm之间为粉状矿。在此基础上,提出了分粒级筑堆技术,即先对矿石进行分级,然后按粒级分区筑堆,对不同粒级浸堆采用不同的布液强度。该项技术应用在云南某铜矿,消除了原堆浸生产中浸堆表面的径流与积液现象,产出铜离子浓度达到萃取要求的合格浸出液,铜浸出率达到了63.98%,使堆浸—萃取—电积生产恢复正常。

地浸施工中钻孔弯曲的危害及预防措施

地浸开采的成败很大程度上取决于钻孔工程质量。影响钻孔工程质量的因素很多,对其中的钻孔弯曲问题作了全面分析并提出了解决办法。

七四五矿就地破碎浸出试验研究

在七四五矿对常规方法开采无经济价值的一独立矿体进行了万吨级就地破碎浸出试验。试验中，采用了深孔爆破落矿筑堆，为了控制筑堆形状和矿石粒度，对深孔落矿方式和参数作了分析研究；根据试验矿体的具体开采技术条件，选择了适宜的采场底部结构，实现了多点集液，达到了防止浸出液漏失的目的。

某铀矿地浸采铀工艺钻孔施工监理的质量控制

针对某铀矿地浸采铀工艺钻孔施工特点,分析影响地浸采铀工艺钻孔施工质量的主要因素,根据工程监理质量控制的一般原理和技术方法,制定了钻孔施工监理的质量控制措施并予以实施。这些措施实施后,钻孔施工中关键工序的质量事故明显减少,钻孔施工质量达到预定的控制目标。

几种进度控制方法在某地浸铀矿山钻孔工程中的应用

以新疆某地浸采铀钻孔施工项目为研究对象,分析了目前工程在进度管理中存在的问题;在现有进度控制的基础上提出通过持续时间、实物工作量和投资量3种进度指标来评价项目进度;采用横道图法、S曲线法和赢得值法作为进度评价的手段和工具,对原先的进度控制系统进行了优化。

应用型高校物联网工程专业建设与实践教学研究

尽管我国物联网发展与全球同处于起步阶段,初步具备了一定的技术、产业和应用基础,但物联网的发展速度很快,社会需要基础扎实、实践能力强、具有创新意识的应用型人才,这就造成高校专业人才培养和社会需求的脱节。为了提高应用型高校物联网工程专业人才的能力,进行了专业理论课程体系的构建、实验和实践体系的建设以及实践教学方式方法的改革,以期所培养的毕业生具备创新意识和创业能力,满足物联网技术发展对人才的市场需求。

原地破碎浸出法开采低品位铀矿体的应用与实践

本文详细地介绍了用原地破碎浸出采矿法试验性开采某铀矿体的方法 ,具体地阐述了原地破碎浸出采矿法的矿体选择、落矿筑堆工艺、布液浸出工艺等内容。该方法取得的成功 ,为采用常规采矿法的铀矿山回收更多的低品位铀矿金属提供了成功方法 ,为大力发展原地破碎浸出溶浸采矿法提供了成功经验。