柿竹园含铍含氟铋精矿冶金新工艺

采用氯化干馏法对柿竹园含铍含氟铋精矿进行了研究，结果表明：采用循环浸出和低酸度、高金属离子浓度体系，铋的浸出率达９９．２２％，浸出液含铋接近３００ｇ／Ｌ。在一定的干馏条件下，氯化铋的干馏率为９８％，其纯度达９９％以上。该工艺将铍和氟富集在浸出渣和干馏渣中，使其污染减小到最低限度。     

铂钯精矿湿法分离Bi、Fe富集贵金属工艺

以铜阳极泥分铜液还原所得铂钯精矿为原料,根据其矿物特性选择HCl作为浸出剂湿法脱除Bi、Fe等主要贱金属元素,富集Au、Ag、Pt、Pd等贵金属;通过热力学计算绘制Bi(Ⅲ)、Fe(Ⅲ)在盐酸体系的组分分布图,实验考察了HCl浓度、Cl-浓度、反应温度和时间等因素对Bi、Fe浸出率的影响.结果表明:在HCl浓度为2 m...     

纳米氧化铝粉体的绿色合成

以廉价的铝锭和异丙醇为起始原料,采用独特的分离提纯、回收再利用技术和溶胶凝胶工艺,合成高性能纳米氧化铝粉体,并利用TEM,XRD和石墨炉原子吸收法等对粉体的相组成、形貌和杂质含量进行分析研究.得出原料对粉体的形貌和组成没有影响,两种不同的Al源均制备出了粒径为10～20nm,球形γ-Al2O3粉体;而原料和蒸馏工艺对纳米氧化铝粉体的纯度有影响,随铝锭纯度的增加,所制备的纳米氧化铝所含的微量杂质含量明显下降.和一次蒸馏相比,二次蒸馏所得产物的主要微量杂质明显下降.利用重熔铝锭为原料,采用二次蒸馏工艺,制得了纯度高达99.99%的纳米氧化铝,且在制备过程中没有废液,废气排出,实现了高纯纳米氧化铝粉体的低成本、环保型生产.     

PHASE EQUILIBRIUM OF SBCL_3-HCL-H_2O SYSTEM

ＰＨＡＳＥＥＱＵＩＬＩＢＲＩＵＭＯＦＳｂＣｌ３－ＨＣｌ－Ｈ２ＯＳＹＳＴＥＭＤｕａｎ，Ｘｕｅｃｈｅｎ；Ｚｈａｎｇ，Ｄｕｏｍｏ；Ｚｈａｏ，Ｔｉａｎｃｈｏｎｇ（ＣｅｎｔｒａｌＳｏｕｔｈＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｃｈａｎｇｓｈａ４１００８...     

铑(Ⅲ)氯水配合物在水溶液中的热力学和动力学平衡行为研究

作者详细研究了各铑(Ⅲ)氯水配合物在水溶液中随时间、温度变化而变化的规律,获得的结果表明,CT浓度是影响铑(Ⅲ)在各种态中分布的主要因数,但是,对于阴离子种态,其放置的时间和温度也是不可忽略的。对于下面这个短的平衡反应链：fac-[RhCl3(H2O)3]→←K34^c cis-[RhCl4(H2O)2]^-→←K45^c [RhCl5(H2O)]^2-→←K56^c [RhCl6]^3-作者系统的研究了在不同温度下其各种态的分布,结果发现,fac-[RhCl3(H2O)3]的含量随温度的升高而增加,而cis-[RhCl4(H2O)2]^-、RhCl5(H2O)]^2-和[RhCl6]^3-却随温度的升高而降低。氯代和水合作为铑(Ⅲ)氯水配合物在溶液中的竞争反应,在放置开始,氯代占优势,但随时间的延长,水合逐渐趋于优势。     

Einflüsse von HCl und N2 auf die Hochtemperaturkorrosion in Atmosphären mit niedrigem Sauerstoffdruck

Influence of HCl and N₂ on high temperature corrosion in atmospheres with low oxygen pressures The effects of HCl and N₂ on the high temperature corrosion in atmospheres with low oxygen pressures were investigated. Investigations of the alloy Fe-20Cr in He-H₂-H₂-O-HCl atmospheres at 1173 K under conditions, where no condensed chlorides could be formed, show the simultaneous growth of Cr₂O₃ and evaporation of CrCl₂. The kinetics of the reactions can be described by growth of Cr₂O₃ according to the parabolic rate law and transport of CrCl₂ in the gas flow following a linear rate law. During heating of the samples in He-H₂-H₂O-HCl condensed chlorides are formed which decrease the adherence of the oxide layers and cause oxide spallation during cooling. This can be avoided either by preoxidation in H₂-H₂O or heating in dry hydrogen. The porosity of Cr₂O₃ layers is not enhanced when HCl is added to the gas atmosphere. The oxidation and evaporation is enhanced in N₂-H₂-H₂O-HCl atmospheres compared to He-H₂-H₂O-HCl atmospheres. The Cr₂O₃ scales are coarse grained and poros. The enhanced porosity is caused by the nucleation and growth of chromium nitrides in the transient state of oxidation.     

Evaporation behavior of low carbon ferromanganese alloy melt at reduced pressure

The distillation of an industrial Fe-Mn alloy at a high temperature and under a low pressure was suggested as an efficient method for manufacturing high purity manganese in our study. This study examined the evaporation behavior of a low carbon ferromanganese alloy melt at reduced pressure. The melt temperature, pressure, initial specific surface area of the melt and reaction time were considered as experimental variables. The evaporation ratio of manganese increased sharply in the initial reaction and remained relatively constant under various experimental conditions. The evaporation rate of manganese increased with an increasing temperature and the initial specific surface area of the melt and decreasing pressure. The activation energy of the manganese evaporation reaction decreased with a decreasing pressure. The initial specific surface area of the melt had a lesser effect than pressure. An empirical equation was derived for the rate of manganese evaporation from a low carbon ferromanganese alloy melt.     

Wear Properties of Plasma Nitrided H13 Steel at Room and Elevated Temperature

H13 steel was nitrided using a plasma surface alloying technique at the temperature of 570℃.The nitrided layers with different thicknesses and components were obtained by changing nitriding pressure.The microstructure and composition of the nitrided layers were evaluated by optical microscopy(OM)and X-ray diffraction(XRD).The wear properties of the nitrided layer against Al2O3 ball at room temperature using a ball-on-disc tribometer and against Si3N4 ball at elevated temperature using a HT-2001 abrasive wear test machine were investigated.The results show that the nitrided layers are composed of compound layer and diffusion layer at the pressure of 100 and 450 Pa.No obvious compound layer appears at pressure of 200 and 300 Pa.XRD analysis shows the nitrided layers are mainly composed ofε-Fe2-3N,γ’-Fe4N,α-Fe,Fe2O3 and Fe3O4 phases.The surface hardness of plasma nitrided H13 steel is about 1100HV0.050 doubled that of substrate.The room temperature friction coefficient of H13 steel is reduced and wear rate is decreased by nitriding at 200 and 300 Pa.Elevated temperature wear test indicates the nitrided H13 steel at the pressure of 100 Pa shows lower friction coefficient and wear rate which are reduced more than 6 times compared with that of H13 substrate.     

Influences of dehydrating process on properties of ATO nano-powders

1　INTRODUCTIONCrystallineSbdopedtinoxide (ATO) ,cassiteritestructure ,isawidebandgapn typesemiconductor.Be causeofitsopticalproperty (transparentforvisiblelightandreflectiveforIR )andelectroconductibility ,goodchemicalandmechanicalstability ,ithasmanyapplica tions,suchastransparentconductiveelectrodes ,photo voltaicdevices ,photosensors ,catalyst,antistaticcoatingsandelectrochromicmaterials[14 ] .AvarietyoftechniqueshavebeenusedtoprepareATOsuperfinepowders ,someinvolvedryprocesses ,ot…     

微乳法制备氧化锆纳米粉体

以可溶性锆盐溶液—环己烷—聚乙二醇辛基苯醚—正戊醇体系的微乳液反应为基础 ,以氨水为沉淀剂 ,在微乳液中发生化学反应产生凝胶状沉淀 ,经洗涤、焙烧得到超细分散 Zr O2 纳米粒子。本文在微乳液法的基础上加入了一种较新的脱水工艺—共沸蒸馏制备了纳米 Zr O2 粉末。通过比表面积 (BET)、透射电镜 (TEM)、X-射线衍射 (XRD)对样品进行了形态表征和物相分析 ,结果表明通过本方法制备的 Zr O2 纳米粉末尺寸可控制在小于 4 0 nm的范围内 ,并具有良好的分散性。共沸蒸馏能充分地脱去凝胶中残余的水分 ,防止因含水胶体干燥过程引起的粉末硬团聚 ,从而显著地提高了粉末的性能     

Recovery of cadmium by high-temperature vaccum evaporation from Ni-Cd batteries

1　INTRODUCTIONPortableelectricityhasbecomeapartofdailyliving .Batteriesempowermanykindsof portableelectricandelectronicdevicestobeused ,butonthecontraryattheirend of lifetheycanharmtous .Ev eryyear 4 0 0millionpiecesofspentNi CdbatteriesproducedinChina[1,2 ] .Ifthespentbatteriesaredis cardeddirectlyintotheenvironment,soilandwaterare potentially polluted .Atthesametime ,largequantitiesofusefulsubstancesaredisposedwithoutrecycling .Therefore ,therecoveryandtreatmenttechnologiesofNi Cdba…     

Solubility of ammonium paratungstate in the system NH_3·H_2O·H_2O

The equilibrium solubilities of 5(NH4)O·12WO3·5H2O (APT·5H2O) were determined at the terminal ammonia concentration of 2 mol/L at 87-95℃. Experimental data were regressed. The linear functional relation between the solubility of APT- 5H2O and the temperature (t /℃) is given as y = - 588.08 + 7.28t. The solubility of the species as a function of the terminal ammonia concentration (x / mol · L-1) is also achieved: y = 36.76 + 18.86x. The solubility of APT · 5H2O produced by ion-exchange method in China is much lower, which is due to much lower silica, much higher NH4Cl, and a small amount of APT · 7H2O with low solubility in the APT crystals. APT · 7H2O forms because of a large amount of NH4Cl and the low activity of water in the crystallization.     

Dissolution kinetics and thermodynamic analysis of vanadium trioxide during pressure oxidation

The dissolution kinetics of vanadium trioxide in sulphuric acid-oxygen medium was examined. It was determined that the concentration of sulphuric acid and stirring speed above 800 r min 1 did not significantly affect vanadium extraction. The dissolution rate increased with increasing temperature and oxygen partial pressure, but decreased with increasing particle size. The dissolution kinetics was controlled by the chemical reaction at the surface with the estimated activation energy of 43.46 kJ·mol-1. The l...     

铜电解液净化中铜砷的分离与回收(英文)

经二氧化硫还原、蒸发结晶,使铜电解液中铜、砷、锑和铋得到有效去除。结晶产物经过溶解、氧化、中和、沉淀、过滤和蒸发结晶,得到三氧化二砷和硫酸铜。当采用SO2将铜电解液中As(Ⅴ)充分还原为As(Ⅲ),并加热蒸发浓缩铜电解液中硫酸浓度至645g/L时,铜电解液中铜、砷、锑和铋的去除率分别为87.1 %,83.9 %,21.0 %和84.7%。在温度30℃,将65g结晶产物溶于200mL自来水时,砷的去除率为92.81%。将所得滤液在如下条件下净化:n(Fe):n(As)为1.2,双氧水为理论用量的19倍,氧化温度为45℃,氧化时间为40min,终点pH为3.7,净化后蒸发浓缩结晶,所得硫酸铜溶液中硫酸铜含量达到98.8%。     

NiAl-W共晶定向凝固组织控制与W介纳米丝形貌

在300 K/cm 的温度梯度条件下,实施不同抽拉速率下的NiAl-1.5at%W共晶合金定向凝固,分析研究抽拉速率对W纤维相相间距、纤维相尺寸的影响规律,并使用盐酸双氧水溶液对NiAl基体进行选择性溶解,制备出当量直径小于500nm的钨纤维丝束。研究结果表明：随着抽拉速率的增大,W纤维相截面形状圆度增加, W纤维相相间距和W纤维相截面当量直径均减小,两者的比值在6.12到7.54之间,经选择性溶解获得W纤维具有多样的三维形貌,呈现出薄带状、珍珠串状和搭接状,发现其形貌与抽拉速率有关。     

Y2O3掺杂ZrB2-SiC基超高温陶瓷的抗烧蚀性能

为改善ZrB2-SiC基超高温陶瓷的抗氧化和抗烧蚀性能,在制备过程中加入Y2O3。用氧乙炔火焰法来考察ZrB2-SiC-Y2O3的抗氧化和抗烧蚀性能。采用SEM和XRD分析烧蚀前后形貌及物相。材料在加热和冷却过程中没有出现开裂现象,说明其具有良好的抗热冲击性能。微观组织分析表明,氧化层主要由4层组成,且氧化层与基体层没有明显的剥离。结果表明:Y2O3的添加可以将氧化产物中的高温稳定相稳定到室温,减少由于相变发生的体积膨胀,改善氧化层与基体层的粘结性能。     

Einfluß von HCl und Cl2 auf die Hochtemperaturkorrosion des 2 1/4 Cr 1 Mo-Stahls in Atmosphären mit hohen Sauerstoffdrücken

Influence of HCl and Cl₂ on high temperature corrosion of 2 1/4Cr 1 Mo Steel in atmospheres with high oxygen pressures The oxidation of the 2 1/4 Cr 1 Mo steel was investigated at 773 K in oxidizing He-O₂-HCl atmospheres. The addition of HCl to He-O₂ atmospheres leads to accelerated oxidation rates. Below porous and cracked oxide scales condensed chlorides are formed. At low HCl pressures 0–1000 vppm the “active oxidation” is determining the corrosion process; i.e. oxidation of evaporating chlorides within the oxide scale. For higher HCl contents 1000–3000 vppm the corrosion behaviour changes to paralinear; i.e. simultaneous parabolic oxide growth and linear mass loss by chloride evaporation.     

化学分离法分析大型纸浆发电厂废渣中生物质底灰和飞灰成分(英文)

采用三步分离法,其中第一步用水,第二步用乙酸铵,第三步用盐酸,提取纸浆发电厂生物质飞灰和底灰的组分,以评估这些残渣的浸出行为。除了Mo、S、Na以及那些浓度低于检测范围的元素外,在这两种灰份中,对于其他元素这三种浸出剂的浸出能力从弱到强的顺序为:水、乙酸铵和盐酸。采用三步分离法处理的废渣中元素浓度比前期用BCR连续提取法得到的低。     

Synthesis of GdF3 from the Gd2O3-NH4HF2 system

GdF3 was synthesized with Gd2O3 and NH4HF2 under atmospheric pressure and vacuum. The effects of pressure,temperature,and reactant ratio on the reaction process were investigated. A new mechanism for the synthesis of GdF3 was proposed. Powdered Gd2O3 started to react with NH4HF2 at low temperature,and the products were GdNH4F4,NH4F,NH3,and H2O. GdNH4F4 decomposed to GdF3 and NH4F after further high-temperature treatment,accompanying the volatilization and decomposition of NH4F. The whole process could be divided into three steps： synthesis,decomposition,and deamination. The initial and final reaction temperatures decreased under vacuum condition. An optimized process for the preparation of GdF3 was obtained： synthesis under atmospheric pressure at low temperature and decomposition and deamination under vacuum at high temperature.     

镁合金微弧氧化层上低温化学镀镍研究

研究了在镁合金微弧氧化陶瓷层上进行低温化学镀镍的工艺,并对镀层的成分、结构和耐蚀耐磨性能进行了分析。实验确定,在40℃左右对陶瓷层进行有效化学镀镍的镀液配方为:NiSO4.6H2O 40g/L,NaH2PO2.H2O 40g/L,(CH2CH2OH)310mL/L,C6H8O7.H2O 7.5g/L,NH4HF 20g/L,用NH3.H2O调节pH值保持在9.5左右。采用上述镀液在40℃施镀,得到的镀镍层为低磷微晶结构,与陶瓷层结合紧密且对陶瓷层有封孔作用,耐蚀和耐磨性能良好。