原镁及镁合金生产的环境影响分析

运用生命周期评价方法(Life Cycle Assessment,LCA),并结合镁工业在节能降耗方面的技术进展,定量评价了2009年我国原镁和镁合金生产过程的资源、能源消耗及其主要污染物的排放。研究表明,我国皮江法炼镁在提高能源利用效率和环保治理等方面取得了长足的进步,特别是还原过程节能技术的应用对于污染物减排起到了关键作用。与2005年相比较,2009年原镁过程的不可再生资源消耗和温室效应均有显著的降低。其中,温室效应的影响与2005年相比下降了约三分之一。通过系统边界的延伸,进一步研究了气体保护法生产AM60镁合金的环境负荷,并分析了原镁和原铝在镁合金生产过程中的环境负荷积累效应。结果表明,原镁生产过程的环境负荷在镁合金生产的积累环境负荷中起到了决定性的影响。     

工业硅生产能耗及节能分析

工业硅生产既消耗一次能源，又消耗二次能源，各厂还原剂选择不同，仅有交流电耗可比，为了进行综合能耗的计算，本文对工业硅生产的能耗项目、可比能源折算办法、折算率等进行了初步分析和节能讨论。建议采取考核综合能耗的办法．分析吨硅产品能耗和万元产值能耗等重要社会效益指标。     

工业硅生产中的节能技术

本文就我国工业硅生产能耗高的状况进行了分析，结合国外工业硅生产的先进技术和装备，指出我国目前工业硅生产能耗高的原因及改进的措施，并简述了我国工业硅生产中需要采取的节能技术及今后的发展方向。     

低碳经济和锻造行业的节能减排

据测算．实施节能减排改造后吨锻件消耗动能费用图比下降60%以上。年节能2．5万吨以上标煤。减少SO2排放量95t．减少水损70万吨．削减COD排放量350t。排污总量减少90％。     

铜加工节能减排途径探索

为了铜加工节能减排战略目标的实现,笔者总结了目前国内外先进的铜加工技术,并根据我国铜加工技术和政策现状,对铜加工节能减排的途径进行探索。进入新世纪以来,我国铜加工业迅速发展,铜材总产量从2001年的185.8万吨增加到2009年的890万吨,从2004年起,连续6年居世界第一位。我国已成为世界     

973计划项目“水泥低能耗制备与高效应用的基础研究”进展顺利

我国水泥产量白1985年以来一直位居世界第一,2009年产量高达16．4万吨。水泥行业具有能耗高、污染重、二氧化碳排放多等特点,尤其是生产过程中的烧、磨环节。如何降低水泥生产过程中的能量消耗,减少二氧化碳排放,对于节能减排具有重要意义。     

2011年全国铝及镁合金熔铸技术交流会通知

节能减排、推进低碳经济是我国经济发展的主要任务之一。2010年我国铝加工材产量超过了2000万吨。熔铸是铝加工过程中对产品质量具有决定性影响的首道工序。     

珠峰锌业冶炼装置完成20天维修

今年1-5月，株洲冶炼集团有限责任公司节能减排攻坚战取得重大进展，铅锌产品每吨综合能耗达到0．7327吨标准煤，同比降低11．24％；电解直流单耗等多项指标达到国际先进水平。节能总量提前实现了全年节能2万吨标准煤的目标。     

二氧化硅微粉用途正在扩大

挪威Elkem公司1985年向日本出口1500吨二氧化硅微粉,1986年的目标达3000吨,5年后将达10万吨。二氧化硅微粉是从硅铁、工业硅的生产过程中所产生的副产品中提炼出来的,粒度为0.2微米,适于做炉用材料、耐火砖用混合材料,还可用于玻璃丝、工程塑料、环氧树脂、陶瓷生产等方面,并正研究用于做各种混凝土。     

铝电解槽系统测试技术在企业节能减排中的应用

铝电解行业是我国的重点耗能行业,节能减排是电解铝生产管理和技术创新过程中的重中之重.铝电解槽系统测试技术包括电压平衡测试、能量平衡测试、工艺技术条件测试、电解质体系测试、流速场测试、磁场测试、电流效率测试技术和系统评价技术等.铝电解槽系统测试技术可针对电解槽物理场、工艺技术参数等进行全面评价,有效找出企业存在的节能潜力,开展全程对标,指导企业节能减排工作.本文论述了铝电解槽系统测试技术在铝电解企业节能减排中的实践.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.