攀枝花钛铁矿的氢气还原动力学（英文）

采用TG、XRD和SEM等分析手段，系统研究了900~1050°C条件下攀枝花钛铁矿的氢气还原过程。结果表明：在900°C恒温还原过程中，还原产物为铁和金红石，当温度高于1000°C时，亚铁板钛矿开始形成。在还原过程中，元素镁会逐渐富集并影响金属化过程。同时，讨论了局部化学反应和相关的还原动力学过程，反应控速步骤为扩散过程。由计算可知，在所选实验条件下，氢气还原攀枝花钛铁矿的表观活化能为117.56kJ/mol，高于合成钛铁矿还原过程中的表观活化能。

黄铜矿在氨水-氯化铵溶液中的界面反应（英文）

对黄铜矿在氨水-氯化铵溶液中的反应界面进行研究。利用X射线光电子能谱分析(XPS)技术对黄铜矿反应界面进行表征。研究发现,覆盖在黄铜矿基底之上的反应界面钝化层由表层的铁氧化物以及被其覆盖的硫化铜组成。黄铜矿结构中的铁离子存在优先溶解现象,形成钝化层中的硫化铜或CuFe_(1-x)S_2。当表层铁氧化物层逐渐自发剥离后,硫化铜层成为新的钝化层。由硫化铜层表面S^(2-), S_2^(2-), S_n^(2-), S^0和SO_4^(2-)等组分含量推算硫化铜的组成。提出黄铜矿在不同p H和氧化电位条件下的氧化和钝化机理。最后,建立黄铜矿界面三步反应模型,剖析钝化层的形成及转化机理。

CaCl_2-NaCl熔盐中电解氧化物制备Ti-Ge金属间化合物（英文）

采用电解脱氧工艺,以不同比例的TiO2和GeO2混合物为前驱体,在电压为3.0 V、温度为800°C的电解条件下,制备Ti-Ge(TixGey)金属间化合物。在同样电解条件下,以5TiO2-3GeO2或5CaTiO3-3GeO2为前驱体时,均可电解得到Ti5Ge3金属间化合物。获得的电解产物表现出相对均匀的晶粒结构。此外,初始原料(TiO2/GeO2)的摩尔比对最终电解产物有非常大的影响。根据实验数据,详细阐述电解脱氧制备TixGey金属间化合物的相关反应机理。结果表明,电解脱氧工艺是一种环境友好的制备TixGey金属间化合物的方法。

Phase transformation and reduction kinetics during the hydrogen reduction of ilmenite concentrate

The reduction of ilmenite concentrate by hydrogen gas was investigated in the temperature range of 500 to 1200℃. The microstructure and phase transition of the reduction products were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and optical microscopy （OM）. It was found that the weight loss and iron metallization rate increased with the increase of reduction temperature and reaction time. The iron metallization rate could reach 87.5% when the sample was reduced at 1150℃ for 80 min. The final phase constituents mainly consist of Fe, M305 solid solution phase （M=Mg, Ti, and Fe）, and few titanium oxide. Microstructure analysis shows that the surfaces of the reduction products have many holes and cracks and the reactions take place from the exterior of the grain to its interior. The kinetics of reduction indicates that the rate-controlling step is diffusion process control with the activation energy of 89 kJ.mo1-1.

Extraction of metals from complex sulfide nickel concentrates by low-temperature chlorination roasting and water leaching

The recovery of valuable metals from complex sulfide concentrates was investigated via chlorination roasting followed by water leaching. A reaction process is proposed on the basis of previous studies and the results of our preliminary experiments. During the process,various process parameters were studied,including the roasting temperature,the addition of NH_4 Cl,the roasting time,the leaching time,and the liquid-to-solid ratio. The roasted products and leach residues were characterized by X-ray diffraction and vibrational spectroscopy. Under the optimum condition,95% of Ni,98% of Cu,and 88% of Co were recovered. In addition,the removal of iron was studied in the water leaching stage. The results demonstrate that this process provides an effective approach for extracting multiple metals from complex concentrates or ores.

钙化焙烧-酸浸工艺提取低冰镍中有价金属（英文）

利用钙化焙烧-酸浸工艺,以CaO为焙烧添加剂从低冰镍中高效提取有价金属。研究焙烧温度、焙烧时间、添加剂CaO、H2SO4浓度和浸出液固比对有价金属提取率的影响。研究结果表明:在最佳条件下,Ni、Cu、Co和Fe的提取率分别为94.2%、98.1%、92.2%和89.3%。在随后的针铁矿法除铁工艺中,99.6%的Fe从浸出液中以针铁矿的形式分离。阐明CaO的焙烧行为与机理,焙烧过程中CaO与Fe2O3优先反应,抑制有色金属铁氧体的形成,使得金属氧化物(Cu O和NixCu1-xO)在高温焙烧过程中能保持稳定,最终通过稀硫酸溶液浸出实现有价金属的高效提取。

Recovery of rare earth elements from permanent magnet scraps by pyrometallurgical process

In order to recover valuable rare earth elements from Nd-Fe-B permanent magnet scraps, a high-temperature pyrometallurgical process was developed in this work. The magnet scraps were first pulverized and oxidized at 1000℃ in normal atmosphere. The oxidized mixtures were then selectively reduced by carbon in the temperature range of 1400-1550℃. In this way, the rare earth elements were extracted to the form of oxides, whereas Fe and B were separated to metal phase. For improving the purity of rare earth oxides, the effects of temperature and reaction time on the reduction of B_(2)O_(3) in oxide phase were investigated. It is found that increasing reaction temperature and extending reaction time will help the reduction of B_(2)O_(3) contents in rare earth oxide phase. Almost all rare earth elements can be enriched in the oxide phase with the highest purity of 95 %.

Effect of controlled rolling/controlled cooling parameters on microstructure and mechanical properties of the novel pipeline steel

The study of controlled rolling/controlled cooling process parameters which affect the microstructure and mechanical properties of a novel pipeline steel has been optimized by the orthogonal experiment with four factors and three levels in this paper. However, the parameters of thermo-mechanical control process （TMCP） optimized by the Gleeble-3500 hot simulator could not satisfy performance requirements of the X100 pipeline steel. In order to improve the performance of this steel, the influence of finish cooling temperature （FCT） on the microstructure and property is studied in detail. It is found that, as this steel is thermo-mechanically treated by this set of parameters （the start heating temperature, finish rolling temperature （FRT）, FCT and cooling rate of 1,180 ℃, 810 ℃, 350 ℃ and 35 ℃/s, respectively）, the micro- structures are mainly composed of granular bainite （GB） and acicular ferrite （AF）. The effective grain sizes are below 20 μm; the steel reaches the optimal balance between the strength and the toughness; the yield strength is 695 MPa; the tensile strength is 768 MPa; the elongation is 16.6 %; the impact energy is 262 J at room temperature. All indexes could meet the requirements of X100 pipeline steel.

Multiple gaseous reduction of ilmenite: thermodynamic and experimental study

In this paper, the thermodynamics of the reduction of ilmenite using multiple gases (H2/CO) was calculated. It is found that the metallization rate of 20.1%–98.8%, H2 consumption rate of 43.0%–99.1%, and carbon deposition amount of 5.7×10?7?0.49mol can be obtained based on the conditions of hydrogen volume fraction of 10%–90% and temperature of 450–1200°C. Experimental study was also carried out using synthetic ilmenite as initial materials and reduced in a static bed reactor at 1100°C. The metallization rate reaches 97% when the multiple gas (70% H2/10% CO/20% Ar) flow rate is 120ml·min?1. A thermogravimetric analyzer was used to measure the variation of sample weight caused by the deposition of solid carbon. The amount of carbon deposited during experiments reaches its maximum while the original hydrogen volume content is 20%. The experimental results are well consistent with the thermodynamic analysis.

Calculation of phase equilibria in Al-Fe-Mn ternary system involving three new ternary intermetallic compounds

In this study, the Al-Fe-Mn ternary system is reassessed by the CALPHAD method. Three new ternary intermetallic compounds are initially described and a rea- sonable and self-consistent set of thermodynamic parameters are established to describe this system. The 973 K, 1 073K, 1 173K, 1 273K, 1 373K, and 1 473K isothermal sections and the 1 073 K, 1 013 K, 968 K and 913 K isothermal sections at the AI corner as well as the liquidus projection at the Al corner are calculated. It is shown that the calculated results are in good agreement with almost all of the experimental results previously reported.

Performance of Sm_(0.7)Sr_(0.3)CoO_(3-δ) dmembrane under CO_2-containing atmosphere

The permeability and stability of Sm_（0.7）Sr_（0.3）CoO_（3-δ）（SSCO） regarding the special requirements for carbon capture and storage（CCS） application were investigated.Pure CO_ was used as the sweep gas at 900 °C,leading to that the oxygen permeation flux decreases by about 34 %.Several cycles of changing the sweep gas between helium and CO_2 indicate the good reversibility of this degradation.Both carbonate formation and adsorption of CO_2 on the membrane surface are responsible for the degradation of the membrane performance.The better CO_2 resistance results from the substitution of Sm for Sr due to the higher acidity of Sm_2O_3（1.278） than that of Sr O（0.978） and a discontinuous layer of carbonate.