氧气底吹铜熔池熔炼过程的机理及产物的微观分析

对氧气底吹熔炼过程气体喷吹行为、造锍熔炼化学反应机理及熔炼炉内热工作状态进行理论分析及水模型实验和取样分析验证。结果表明,氧气底吹气流能使熔体形成均匀的扩散区,实现熔体的搅拌,在气体连续相区和液体连续相区,气液、液液之间的相互作用强烈,为炉内化学反应及传热传质提供了良好的动力学条件;氧气底吹熔炼过程在零配煤的情况下能达到自热熔炼,在节能减排方面,该工艺具有很强的优势;获得了铜渣、冰铜和蘑菇头中各组分的形貌,确定了铜渣、冰铜和蘑菇头的物相组成,渣样主要由冰铜相、磁铁矿相、铁橄榄石相和玻璃体相组成,熔炼内的氧势和硫势分布有利于反应的进行,能有效抑制Fe3O4的形成以及降低渣含铜。     

Characterisation of rare earth minerals with field emission scanning electron microscopy

Abstract

Rare earth elements are becoming increasingly in demand, due to their prevalence in both renewable energy devices and high end electronics. The characterisation of the composition and morphology of the various phases that have valuable rare earth elements in the ores are needed in conjunction with the study of their physicochemical properties to optimise industrial process to extract the minerals containing the rare earth elements. Rare earth bearing minerals contain many elements with overlapping X-ray peaks (L- and M-lines) with an energy dispersive spectrometry detector, requiring a high degree of X-ray energy resolution. A program was developed to obtain the intensity of each peak by deconvolution of the X-ray spectrum. Low accelerating voltage of less than 5 kV and small beam diameter of less than 10 nm of a cold field emission scanning electron microscope allow x-ray microanalysis on the nanometre scale. A 100 nm wide phase was observed at 4 kV on a backscattered electron micrograph. Furthermore, a small beam diameter of less than 10 nm was used for identification of small phases of a few micrometres.

Les éléments de terre rare sont de plus en plus en demande, grâce à leur prévalence tant dans les dispositifs d’énergie renouvelable que dans l’électronique de haute gamme. On a besoin de caractériser la composition et la morphologie des différentes phases qui contiennent des terres rares de valeur dans les minerais, en combinaison avec l’étude de leurs propriétés physico-chimiques, afin d’optimiser le procédé industriel d’extraction des minéraux contenant les terres rares. Les minéraux porteurs de terre rare contiennent plusieurs éléments ayant des pics de rayons x qui se chevauchent (lignes L et M) avec un détecteur de spectroscopie à dispersion d’énergie, nécessitant une haute résolution énergétique. On a développé un programme visant à obtenir l’intensité de chaque pic par déconvolution du spectre de rayons x. Un faible voltage d’accélération de moins que 5 kV et un faisceau à faible diamètre de moins que 10 nm d’un microscope électronique à balayage par cathode froide permettent la microanalyse des rayons x à l’échelle du nanomètre. On a observé une phase de 100 nm de largeur à 4 kV sur une micrographe d’électrons rétrodiffusés. De plus, on a utilisé un faisceau de faible diamètre de moins que 10 nm pour l’identification de petites phases de quelques μm.     

Cells on biomaterials – some aspects of elemental analysis by means of electron probes

Electron probe X‐ray microanalysis enables concomitant observation of specimens and analysis of their elemental composition. The method is attractive for engineers developing tissue‐compatible biomaterials. Either changes in element composition of cells or biomaterial can be defined according to well‐established preparation and quantification procedures. However, the qualitative and quantitative elemental analysis appears more complicated when cells or thin tissue sections are deposited on biomaterials. X‐ray spectra generated at the cell/tissue–biomaterial interface are modelled using a Monte Carlo simulation of a cell deposited on borosilicate glass. Enhanced electron backscattering from borosilicate glass was noted until the thickness of the biological layer deposited on the substrate reached 1.25 μm. It resulted in significant increase in X‐ray intensities typical for the elements present in the cellular part. In this case, the mean atomic number value of the biomaterial determines the strength of this effect. When elements are present in the cells only, the positive linear relationship appears between X‐ray intensities and cell thickness. Then, spatial dimensions of X‐ray emission for the particular elements are exclusively in the range of the biological part and the intensities of X‐rays become constant. When the elements are present in both the cell and the biomaterial, X‐ray intensities are registered for the biological part and the substrate simultaneously leading to a negative linear relationship of X‐ray intensities in the function of cell thickness. In the case of the analysis of an element typical for the biomaterial, strong decrease in X‐ray emission is observed in the function of cell thickness as the effect of X‐ray absorption and the limited excitation range to biological part rather than to the substrate. Correction procedures for calculations of element concentrations in thin films and coatings deposited on substrates are well established in materials science, but little is known about factors that have to be taken into account to accurately quantify bioelements in thin and semi‐thick biological samples. Thus thorough tests of currently available quantification procedures are required to verify their applicability to cells or tissues deposited on the biomaterials.     

城市污水中总砷测定

用氢化物发生 -原子荧光光谱法测定城市污水中总砷 ,确定了试验的最佳测定条件。结果表明 :砷的测定线性范围为 5～ 5 0 ng/ m L,回收率 10 0 %～ 10 3% ,测定 6条标准曲线的剩余标准差为 1.3,检出限为 0 .2 6 ng/ m L,该方法可用于测定其它不同水体中的总砷。     

Co-Cu-Zn三元系相平衡的实验研究

本实验通过采用电子探针显微分析和X-ray衍射分析方法实验研究了Co-Cu-Zn三元体系在800°C和1000°C时的相平衡。在这两个等温截面中均未发现三元化合物。在800°C等温截面,Co在β-CuZn相中的固溶度为32.36%,Cu在β1-CoZn相中的固溶度为5.28%。除此之外,γ-Co5Zn21和γ-Cu5Zn8具有相同的晶体结构,因此,它们之间形成了一个贯穿连续固溶体相。1000°C的等温截面中,β-CuZn相、β1-CoZn相、γ-Co5Zn21相、γ-Cu5Zn8相都消失了。随着温度从800°C上升到1000°C,液相区域增大。     

Study on M／A islands in pipeline steel X70

The free structure of M/A islands in pipeline steel X70 has been studied by transmission electron microscope (TEM). It is shown that the M/A islands are about 1-2 μm in size and distribute at the grain boundary of irregular massive ferrite or acicular ferrite in the microstructure of the steel undergoing TMCP (thermo-mechanical controlled processing). The analysis of diffraction contrast shows that the M/A islands consist of retained austenite and some martensite lamellae different in size and orientation. The microtwinning and midrib exist in the lamella of lenticular martensite, which exhibit the typical character of high-carbon martensite. The influences of TMCP parameters on M/A islands have been studied carefully. With the increase of the cooling speed, the amount of M/A islands decrease slightly and the morphology of M/A islands changes to thin dispersive short bars from thick irregular long strips.     

稠油油藏高温凝胶改善蒸汽驱开发效果可视化实验

针对稠油油藏蒸汽驱汽窜现象严重的问题,为了研究高温凝胶改善稠油注蒸汽开发的效果,利用二维可视化物理模拟设备,通过图像采集系统对比了注入高温凝胶前、后的图像,并全程跟踪了蒸汽驱开发稠油时汽窜产生的过程以及注高温凝胶后蒸汽驱油层的波及情况,据此研究了利用高温凝胶改善蒸汽驱开发效果的微观机理。实验结果表明:稠油蒸汽驱过程中,由于压力梯度的差异,注采井间容易形成窜流通道;蒸汽在油层中产生明显的指进现象,从而降低蒸汽的波及范围,窜流通道两侧存有大量的剩余油;凝胶溶液首先进入窜流通道,并占据颗粒间的大孔隙,成胶之后对高渗通道有良好的封堵作用;后续注入的蒸汽绕过主流通道,能够进一步驱出剩余油。驱油结果表明:注入凝胶之后的最终波及效率能够达到70.44%,最终驱油效率达到60.45%,分别比单纯蒸汽驱提高了22.35%和15.17%。     

盐及盐卤中微量铁铝钙镁的连续测定

介绍了用ＥＤＴＡ络合滴定法连续测定盐及盐卤中微量铁铝钙镁的原理和步骤。回收率在９８．５％～１０３．９％之间，方法简便，具有连续快速的特点。     

The influence of oxide surface layers on bulk electron probe microanalysis of oxygen—application to Ti-Si-O compounds

This paper discusses a generalized method to measure with the electron probe microanalyzer (EPMA) the oxygen in a material containing a surface oxide layer. The continuum background is the most difficult to measure, particularly for materials in which oxygen-free samples cannot be produced. The method depends on the preparation of either oxygen-free samples or well characterized oxygen-containing samples. Specific application of the method to the Ti-Si-O system is discussed. In addition, measurements of oxide surface-layer thickness of 3.6–8.0 nm on Ti and Ti-Si compounds were obtained using EPMA and a scanning Auger microprobe (SAM). The nature of the oxide surface layers was shown using x-ray photoelectron spectroscopy (XPS).