Progress in gold solvent extraction

Gold solvent extraction has been used to recover gold by analytical chemists for about one century. Due to the potential advantages of solvent extraction technology over present zinc-dust cementation and carbon-adsorption procedures in gold recovery, metallurgists have paid much attention to the study of gold solvent extraction in recent years . Some promising extraction systems were proposed and studied. Recently some new progress in gold solvent extraction have been achieved in our research group. In the mechanism study on quaternary amine extraction system, a supramolecular structure model based on hydrogen bonding between modifier and Au(CN)2~ was proposed. For the stripping of quaternary amine extraction system, a procedure based on NaCI04 solution and saturated KCl solution was reported.     

Review on aggregation of acid extractants in solvent extraction of metal ions: remark on the general model

The aggregation behavior of various acid extractants in the solvent extraction systems of metal ions is re-examined and explained according to knowledge obtained in recent work. The conclusions are as follows. (1) Complexes formed by the extractants and metal ions can form reversed micelles in organic diluents, depending on the microstructures of the complexes. The dimers of the acid extractant cannot percolate to the metal-extractant aggregates, and the acid-salt complexes are always formed in the aggregates. The reversed micelles or the W/O microemulsions formed by different species cannot be associated with each other to form a unified aggregate. (2) In solvent extraction systems, hydration of the extractants and metal ions can be considered as the driving force of forming reversed micelles. (3) Information of the first approach to the insight of the bicontinuous microemulsion of NaDEHP shows that various components in the aqueous phase behave confined and very similar to the typical AOT/n-heptane W/O microemulsions. (4) In the extraction of lanthanide ions by the W/O microemulsion of sodium naphthenate, the saponification is a process of forming reversed micelle or W/O microemulsion, while the extraction step is a process of destroying reversed micelles or W/O microemulsion droplets.     

Process development for the direct solvent extraction of nickel and cobalt from nitrate solution: aluminum,cobalt, and nickel separation using Cyanex 272

A direct solvent extraction(DSX) process for purifying nickel and cobalt from the nitric acid leach solution of nickel laterite ores was conceived and experimentally probed. The proposed process consists of two solvent extraction(SX) steps but with only one extractant — bis(2,4,4-trimethylpentyl)phosphinic acid(Cyanex? 272) — used in both steps. The first extraction step involved the removal of aluminum and zinc, whereas the second extraction step involved the separation of cobalt along with manganese from nickel. The experimental results showed essentially quantitative removal of aluminum(97%) and zinc(99%) in a single extraction stage using 20vol% Cyanex 272 at pH 2.1. Some cobalt(32%) and manganese(55%) were co-extracted but were easily scrubbed out completely from the loaded organic phase using dilute sulfuric acid at pH ≤ 1.38. Cobalt and manganese in the first extraction raffinate were extracted completely in four extraction stages at staggered pH values of 4.0, 4.4, 4.5, and 4.0 in the first, second, third, and fourth stages, respectively, using also 20vol% Cyanex 272. A small amount of nickel(up to 6.6%) was co-extracted but was easily scrubbed out completely with dilute sulfuric acid at pH 2.0. A flow diagram showing the input and output conditions and the metals separated under the deduced optimum conditions is presented.     

Process development for the direct solvent extraction of nickel and cobalt from nitrate solution: aluminum,cobalt, and nickel separation using Cyanex 272

A direct solvent extraction (DSX) process for purifying nickel and cobalt from the nitric acid leach solution of nickel laterite ores was conceived and experimentally probed. The proposed process consists of two solvent extraction (SX) steps but with only one extractant-bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex® 272)-used in both steps. The first extraction step involved the removal of aluminum and zinc, whereas the second extraction step involved the separation of cobalt along with manganese from nickel. The experimental results showed essentially quantitative removal of aluminum (>97%) and zinc (>99%) in a single extraction stage using 20vol% Cyanex 272 at pH 2.1. Some cobalt (32%) and manganese (55%) were co-extracted but were easily scrubbed out completely from the loaded organic phase using dilute sulfuric acid at pH ≤ 1.38. Cobalt and manganese in the first extraction raffinate were extracted completely in four extraction stages at staggered pH values of 4.0, 4.4, 4.5, and 4.0 in the first, second, third, and fourth stages, respectively, using also 20vol% Cyanex 272. A small amount of nickel (up to 6.6%) was co-extracted but was easily scrubbed out completely with dilute sulfuric acid at pH 2.0. A flow diagram showing the input and output conditions and the metals separated under the deduced optimum conditions is presented.     

Investigation of Phase Inversion of Liquid-Liquid Dispersions in Agitated Vessels

Introduction Liquid-liquid dispersions in agitated vessels are fre-quently used in the chemical industry for conducting operations such as solvent extraction and heterogene-ous reactions. In liquid-liquid two-phase flow systems, usually consisting of an a…     

The active commissioning process for a power reactor spent fuel reprocessing pilot plant in China

The process of a power reactor spent fuel reprocessing pilot plant (hereinafter referred to as the "pilot plant") had been completed through active commissioning. Operational and technological parameters, such as shearing, dissolution, feed clarification, co-decontamination cycle, uranium and plutonium purification cycle, and the uranium and plutonium finishing facility, were identified. In addition, technical devices including extraction and mechanical equipment, electrical installation as well as instrumentation, and auxiliary systems for safety and adaptability were also verified. The commissioning results indicated that the recovery rate and decontamination coefficients of each system satisfied the designed index requirements and the qualified productions, i.e. uranium trioxide and plutonium dioxide, were produced. Monitored values at various monitoring points in the radiological protection system were within the control range and the discharge of waste water and waste gas complied with the relevant standards. This shows that independent and innovative technology for power reactor spent fuel reprocessing had been developed by our country.     

Situation and Development Prospect of Uranium Resources Exploration in China

History of uranium exploration and the general situation of identified uranium resources in China are introduced briefly in the paper, and the feature of uranium resources is summarized as “a large number of deposits, good ore processing properties and centralized occurrence” which should be considered as the advantages. In accordance with the fact that the exploration level of uranium resources is quite low in China, it is pointed out that exploration investment must be intensified from now on to identify more uranium concentrated bases which occurring of middle to large size uranium deposit in order to meet the demand of natural uranium from nuclear power sector. Besides, major scientific and technological achievements on uranium exploration during the past fifty years are elaborated in the paper. According to the exploration ability and uranium resources potential in China, it is believed that uranium exploration can realize the goal of “getting break through both at home and abroad” and meet the requirement of nuclear industry to uranium resources in China by carrying out the uranium resources exploration strategy of “rooted in domestic and opening up abroad”.     

The relationship of differential expression of genes in GA biosynthesis and response pathways with heterosis of plant height in a wheat diallel cross

Heterosis in internode elongation and plant height is commonly observed in hybrid plants, but the molecular basis for the increased internode elongation in hybrids is unknown. In this study, midparent heterosis in plant height was determined in a wheat diallel cross involving 16 hybrids and 8 parents, and real-time PCR was used to analyze alterations in gene expression between hybrids and parents. Significant heterosis of plant height and the first internode in length were observed for all 16 hybrids, but the magnitude of heterosis was variable for different cross combinations. Analysis revealed that the heterosis of the first internode was significantly correlated to that of plant height （r = 0.56, P 〈 0.05）, suggesting that the increased elongation of the first internode is the major contributor to the heterosis in plant height. Real-time PCR analysis exhibited that significant difference in heterosis of gene ex- pression was observed among all cross combinations. Moreover, heterosis of the first internode in length was correlated significantly and positively with expression heterosis of KS, GA3ox2-1, GA20ox2, GA20ox1D, GA-MYB and GID1-1, but significantly and negatively with expression heterosis of GAI and GA2ox-1, which is consistent with our recently proposed model of GAs and heterosis in wheat plant height, suggesting the alteration of GA biosynthesis and response pathways might be responsible for the observed heterosis in plant height.     

Development of an analytical method to determine phenolic endocrine disrupting chemicals in sewage and sludge by GC/MS

An analytical method has been developed to determine hisphenoi A and five degradation products of alkyiphenoi ethoxylates in sewage and sludge. The parameters of accelerated solvent extraction （ASE） were optimized. C18 cartridge was used to clean up the sewage and the extract of sludge. The sensitivity of the mass detector was improved by adjusting the voltage of the lens manually. The instrumental detection limit was 3.2-17.8pg. The method detection limits were 2.5-11.4 ng/L and 0.3-2.1ng/g for sewage and sludge analysis respectively. The recovery and relative standard deviation for sewage analysis were 79.2%-111.4% and 6.9% - 12.6%; for sludge analysis were 68.5% - 114.0% and 8.9%-16.0%. Finally this method was applied to determining the phenolic endocrine disrupting chemicals in sewage and sludge from a sewage treatment plant in Beijing.     

Supercritical Fluid Carbon Dioxide in the Extraction of Lanolin and Its Alcohol

The use of supercritical fluid carbon dioxide (SF-CO_2) in extraction of lanolin and its alcohol issuperior to the conventional solvent extractionmethod. Its distinctive advantages include highextractive ratio, nontoxic and nonflammablesolvents, and minimal by-product pollution. The     

New advances in virtual plant research

Virtual plants are computer simulations of the growth, development and deployment of plants in a three-dimensional space. Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ecology, and remote sensing areas. In this review, we attempt to introduce the significance, modeling methodology, and main advances in virtual plant research and applications. The challenges associated with virtual plant modeling in agronomy applications, including the interaction mechanism between plant and environment and root system modeling, are also discussed. Insights into applications of virtual plants in agronomy are given in the areas of performing virtual experiments to accurately quantify the utilization of soil water and nutrients, to design crop ideotype on computers, and to improve crop planting.     

E-Navigation架构下船舶引航系统

为了提高引航调度效率,保证船舶操纵安全,应用E-Navigation系统架构研发了新型船舶引航系统.该系统采用多分辨率遥感影像、IHO-S57国际标准电子海图等地理空间数据,综合应用了AIS、公网3G及实时海流观测等技术.通过实例,证实该系统是可行的.     

煤粉仓内壁涂层的研究

火电厂煤粉仓的正常给粉是电厂安全运行的重要前提，为解决目前国内电厂煤仓普遍存在的“搭桥”现象，采用在仓内壁面涂上一层特种涂料，减少仓壁与煤粉间摩擦力以解决“搭桥”问题，运行表明方法可行效果也佳．     

福建东山岛野生黄色花系植物调查与分析

在野外调查、标本整理和文献查阅的基础上,分析了东山岛野生黄色花系植物的组成、与邻近地区的关系、生活型、叶级特征、叶质特征、观赏特性、绿化用途和经济用途.结果显示,东山岛野生黄色花系植物71科174属243种,与福建各地区共有种较多的城市集中福建南部沿海地区.东山岛野生黄色花系植物生活型以矮高位芽植物为主,矮高位芽植物有165种,占总种数的72.64%;叶型主要以中、小型为主,有197种,占总种数的84.69%;叶质以纸质、革质为主,有155种,占总种数的64.31%;花期集中在春、夏、秋三季,果期相对集中在夏秋季节.东山岛野生黄色花系植物经济用途广泛,其中以药用为主的有132种,占总种数的54.77%,用于园林绿化的有45种,种类不多,占总种数的18.52%.     

发电企业厂级生产管理监控信息系统设计研究

以某电厂2台300MW机组为对象,对其厂级生产管理监控信息系统的功能结构、数据库环境及网络结构进行了设计．该系统在功能上具有两个突出特点：一是提出了对单元机组设备分层次进行状态等级评价的方法,并提出通过状态评价指标向量实现对单个设备状态的评价,成功实现对全厂辅助设备状态的评价;二是考虑了设备状态对负荷分配的影响,使负荷分配兼顾了经济性和安全性因素．现场运行情况表明,本系统的设计是符合生产现场需求的．对其他电厂开发类似系统也具有一定的参考价值．     

基于浮动式核电站的严重事故源项分析评估技术体系研究

目前针对陆地核电站严重事故开展的源项分析不完全适用于浮动式核电站。以浮动核电站严重事故为研究领域,基于对国内外核电站、研究堆、船用堆源项分析方法和后果评价方法的相关研究,根据浮动核电站的特点,确定了严重事故源项分析计算软件和计算方法,构建出源项分析技术路线图,从而建立了基于浮动核电站严重事故的“MELCOR耦合FLUENT-MACCS”源项评估技术体系。为浮动式核电站的安全运行、安全审评及环境评价提供放射性源项方面的数据支持,为核应急决策提供进一步的理论基础。     

催化裂化动力学模型的建立及其应用

本文应用集总理论,建立了催化裂化十一集总动力学模型,开发了该模型的计算机软件(FCCLK)。利用该软件对工业催化裂化装置和掺炼渣油的中试装置进行了工业验证。结果表明,本模型能够很好地预测不同原料组成、不同操作条件下的催化裂化产物的产率,使工业催化裂化装置实现了优化操作,轻油和汽油收率提高,焦炭产率下降,取得了明显的经济效益。     

江西精油植物资源

江西的自然环境适合于多种植物的生长,境内蕴藏着丰富的精油植物资源。根据多次考察的资料表明,江西境内已发现并有记载的精油植物有98科,750种以上。其中包括自然野生、传统栽培和从境外引种成功的种类。本文详述了精油植物在江西境内不同地域的分布情况,对其中一些有开发价值的精油植物种类着重进行了介绍。为研究、开发、利用这些丰富的资源提供了基本依据。     

植物差异表达基因克隆技术及研究进展

随着分子生物学技术的深入发展,植物基因组研究已经由以全基因组测序为目标的结构基因组学转向以基因功能鉴定为目标的功能基因组学研究,目前分离并克隆差异表达基因已成为生命科学研究的热点.近些年来,国内外学者发展了多种分析差异表达基因的技术来研究植物在不同发育阶段、不同生理状态下的基因表达状况,掌握了生命活动过程中的重要信息.文章对建立在RNA水平上克隆植物未知差异表达基因的几种关键技术及其研究进展进行了综述,阐述了各技术的原理、技术路线、优缺点及相应的改进方法,并对它们在植物抗逆研究中的应用现状及前景作了展望.     

Quantitative evaluation of multi-process collaborative operation in steelmaking-continuous casting sections

The quantitative evaluation of multi-process collaborative operation is of great significance for the improvement of production plan-ning and scheduling in steelmaking-continuous casting sections (SCCSs). However, this evaluation is difficult since it relies on an in-depth un-derstanding of the operating mechanism of SCCSs, and few existing methods can be used to conduct the evaluation, due to the lack of full-scale consideration of the multiple factors related to the production operation. In this study, three quantitative models were developed, and the multi-process collaborative operation level was evaluated through the laminar-flow operation degree, the process matching degree, and the schedul-ing strategy availability degree. Based on the evaluation models for the laminar-flow operation and process matching levels, this study invest-igated the production status of two steelmaking plants, plants A and B, based on actual production data. The average laminar-flow operation (process matching) degrees of SCCSs were obtained as 0.638 (0.610) and 1.000 (0.759) for plants A and B, respectively, for the period of April to July 2019. Then, a scheduling strategy based on the optimization of the furnace-caster coordinating mode was suggested for plant A. Simu-lation experiments showed higher availability than the greedy-based and manual strategies. After the proposed scheduling strategy was applied, the average process matching degree of the SCCS of plant A increased by 4.6％ for the period of September to November 2019. The multi-pro-cess collaborative operation level was improved with fewer adjustments and interruptions in casting.