NaCl对低温铝电解质密度影响的研究

根据阿基米德原理测量了低温铝电解质Na3AlF6-AlF3-Al2O3(3%)-CaF2(3%)-MgF2(3%)-NaCl体系的密度,通过回归正交设计计算得到了NaCl含量(B/%),冰晶石分子比(CR),电解温度(T/℃)与电解质密度(ρ)之间关系的回归:方程ρ=4.354-8.464×10-3T+1.983(CR)+2.023×10-2B-2.882×10-4T(CR)+4 707×10-5TB-1.628×10-2(CR)B+4.109×10-6T2-3.841×10-1(CR)2-2.014×10-3B2以及经简化方程:ρ=2.730 5-1.225×10-3T+2.204×10-1(CR)-2.014×10-3(B-8.292)2,并讨论了NaCl含量对低温铝电解质密度的影响,实验结果表明:氯化钠含量为12%、分子比为1.5时,电解质与铝液的相对密度差大于15%.     

王兆文

根据阿基米德原理测量了低温铝电解质Na3 AlF6-AlF3 -Al2 O3 (3% ) -CaF2 (3% ) -MgF2(3% ) -NaCl体系的密度 ,通过回归正交设计计算得到了NaCl含量 (B/ % ) ,冰晶石分子比(CR) ,电解温度 (T/℃ )与电解质密度 (ρ)之间关系的回归 :方程 ρ =4 .35 4 - 8.4 6 4× 10 -3 T+1.983(CR) +2 .0 2 3× 10 -2 B - 2 .882× 10 -4T(CR) +4.70 7× 10 -5TB - 1.6 2 8× 10 -2 (CR)B+4.10 9× 10 -6T2 - 3.84 1× 10 -1(CR) 2 - 2 .0 14× 10 -3 B2 以及经简化方程 :ρ =2 .730 5 - 1.2 2 5× 10 -3 T +2 .2 0 4× 10 -1(CR) - 2 .0 14× 10 -3 (B - 8.2 92 ) 2 ,并讨论了NaCl含量对低温铝电解质密度的影响 ,实验结果表明 :氯化钠含量为 12 %、分子比为 1.5时 ,电解质与铝液的相对密度差大于 15 %。     

Na_3AlF_6-AlF_3-LiF-MgF_2-La_2O_3-Al_2O_3熔盐体系密度的研究

采用阿基米德法研究温度、单一或混合添加La_2O_3与Al_2O_3对Na_3AlF_6-AlF_3-LiF-MgF_2熔盐体系密度的影响,并用最小二乘法建立了密度数学模型,确定了熔盐密度与温度、 La_2O_3与Al_2O_3加入量之间关系的回归方程,为了使熔盐与所制备的La-Al中间合金液的有效分离,从熔盐密度的角度分析了电解制备La-Al中间合金时的合理电解温度与氧化物加入量。研究结果表明:熔盐密度随温度的上升或Al_2O_3加入量的增加呈现线性降低的趋势,却随着La_2O_3加入量的递增而线性增加;当(质量分数)w_(La_2O_3)∶w_(Al_2O_3)=1∶9时,熔盐密度随La_2O_3-Al_2O_3混合氧化物加入量的增加而线性下降,当w_(La_2O_3)∶w_(Al_2O_3)=3∶7, 1∶1或7∶3时,密度却随La_2O_3-Al_2O_3混合氧化物加入量的增加而线性增加;在温度为905～1055℃, La_2O_3与Al_2O_3加入量分别为0%～5%, 0%～10%(质量分数)的研究范围内,熔盐密度(ρ)与温度(t), La_2O_3, Al_2O_3含量之间的关系为:ρ=3.0231-0.0011t+0.0260w_(La_2O_3)-0.0053w_(Al_2O_3),从而可以确定电解制取La-Al中间合金较为理想的Na_3AlF_6-AlF_3-LiF-MgF_2-La_2O_3-Al_2O_3熔融体系温度应控制在965～995℃之间,氧化物的加入量应满足条件w_(La_2O_3)+w_(Al_2O_3)9%,w_(La_2O_3)∶w_(Al_2O_3)1。     

金属陶瓷5Cu/(10NiO-NiFe2O4)在KF(K3AlF6)-AlF3-Al2O3 熔体中的电解腐蚀

采用粉末冶金技术,制备出组成为5Cu/(10NiO-NiFe-2O-4)的金属陶瓷惰性阳极,并对其在电解质KF(K-3AlF-6)-AlF-3-Al-2O-3熔体中的电解腐蚀行为进行了研究.实验结果表明,对于添加KF或K-3AlF-6的电解质组成,电解质中杂质元素浓度在电解初期相对稳定,而后呈上升趋势;由于铝热还原反应的加剧,电解后阳极腐蚀严重;与传统电解质组成相比,采用低温电解质有利于减缓NiFe-2O-4基金属陶瓷惰性阳极的腐蚀,但需提高熔体导电能力和解决电解过程阴极结壳等问题.     

LiF-DyF_3-Cu_2O-Dy_2O_3熔盐体系密度的影响因素研究

在探索出制取Dy-Cu中间合金方法的基础上,为了进一步优化电解过程的工艺参数,采用阿基米德法对LiF-DyF_3-Dy_2O_3-Cu_2O熔盐体系的密度进行了研究。考察了温度、单一氧化物(Dy_2O_3或Cu_2O)以及混合氧化物(Dy_2O_3与Cu_2O)对熔盐体系密度的影响,并通过最小二乘法对数据进行了拟合,建立了温度、 Dy_2O_3含量、 Cu_2O含量与熔盐密度之间的数学回归方程。研究结果表明,熔盐体系的密度随温度的升高而线性下降,而随单一氧化物加入量、混合氧化物加入量及混合氧化中w_(Dy_2O_3)与w_(Cu_2O)的比值增大而增大。在温度为910～1030℃,w_(Dy_2O_3)为0%～2.0%(质量分数),w_(Cu_2O)为0%～2.0%范围内,温度(t), Dy_2O_3加入量w_(Dy_2O_3), Cu_2O加入量w_(Cu_2O)与熔盐密度(ρ)的关系可以表示为:ρ=-7.01813-0.00163t+0.01832 w_(Dy_2O_3)+0.10289w_(Cu_2O)。从熔体密度角度来看,在氧化物的加入量满足2.0%≤w_(Dy_2O_3)+w_(Cu_2O)≤3.0%,w_(Dy_2O_3)∶w_(Cu_2O)3∶2,电解温度控制在960～980℃的条件下,电解LiF-DyF_3-Dy_2O_3-Cu_2O熔盐制取Dy-Cu合金较为理想。     

LaCl3-KCl熔盐体系物化性质研究

合理选择熔盐体系在电解法制备稀土金属工业生产过程中至关重要。文中采用阿基米德法、拉筒法和连续变电导池常数法（CVCC）测定了不同配比的LaCl₃-KCl熔盐在1 073~1 223 K下的密度、界面张力和电导率。结果表明,随着温度升高,相同成分的LaCl₃-KCl熔盐的密度（ρ）和界面张力（σ）均呈降低趋势,而电导率（κ）逐渐增大;在相同温度下,随着LaCl₃含量增加,LaCl₃-KCl熔盐的密度和界面张力均逐渐增大,而电导率逐渐减小。通过拟合获得密度、界面张力以及电导率的经验公式分别为ρ=a-b×T×10-3、σ=a-b×T×10-3、κ=A+B×T×10-3+C×T2×10-6,明晰了熔盐的物化性质随温度及组分的变化规律,为熔盐电解法制备镧及其镧合金提供科学依据。      

MgF_2—CaF_2—BaF_2—LiF系融盐密度和电导率的测定

测定了MgF_2—caF_2—BaF_2—LiF系融盐的密度和电导率。经回归得到920℃下分子比（MgF_2/CaF_2）为1.25时密度与电导率的回归方程如下:密度d=2.7196+1.192×10~(-2)X_1-3.1×10~(-4)(X_1)~2-2.192×10~(-2)X_2+4.69×10~(-4)(X_2)~2;电导率K=1.5387-2.667×10~(-2)X_1+8.3×10~(-5)(X_1)~2+0.1419X_2-1.854×10~(-3)(X_2)~2（式中X_1、X_2表示BaF_2、LiF质量百分含量。）给出了密度。电导率随温度及成份的变化曲线和等值图。 该体系融盐可以作为液态铝阴极电解氧化镁制取铝镁合金时的电解质。     

B2O3对高铝钢连铸保护渣理化性能的影响

高铝钢连铸过程中,为了避免或减轻钢液中Al与保护渣中SiO2发生反应,设计了低SiO2、高Al2O3含量的高铝钢连铸保护渣,通过添加适量的酸性氧化物B2O3协调熔渣酸碱性,利用实验分析了B2O3含量对高铝钢保护渣熔融特性、黏度特性及渣膜传热特性的影响.结果表明,B2O3含量在4%～10%时,随着B2O3含量增加,保护渣熔化温度、黏度、黏流活化能均降低,渣膜热流密度增加;保护渣的等温转变曲线(TTT曲线)向孕育时间增加的方向移动,晶体生长速率降低;实验条件下,增加B2O3含量可抑制保护渣中CaF2的析出.     

多种铝生产方式的碳核算与减碳潜力分析

依据不同氧化铝生产工艺和电力结构,构建了6种铝的生产方式,并基于生命周期理念,对这6种方式的CO₂排放量进行核算并分析产生差异的原因;同时,设置了不同的低碳路径,挖掘铝工业的减碳潜力.结果表明：生产1 t铝的CO₂排放量,拜耳-水电法最小,为1.86×10³ kg,烧结-火电法最大,为1.20×10⁴ kg;在同种电力结构下,化石燃料、电力和阳极等原料的输入量是影响氧化铝和电解铝生产工序中CO₂排放量的主要因素;在氧化铝生产工艺一致的情况下,用水电替代火电可使铝生产过程中的CO₂排放量降低34%～43%.由减碳路径分析结果可知,绿色电力-清洁工艺(EGP-CP)路径下CO₂减排效果最好,每生产1 t铝的CO₂排放量可降低至7.75×10³ kg,比基准路径(BAU)减少15.68%.     

210 t 复吹转炉-CAS 精炼-连铸流程生产低碳铝镇静钢的洁净度

洁净低碳铝镇静钢(%:0.05～0.06C、0.04Al)由210 t顶底复吹转炉-CAS精炼-连铸230 mm板坯流程冶炼.通过27～28 min CAS密封吹氩处理,钢液T[O]由CAS前(50～60)×10-6降至(19～24)×10-6,中间包钢水T[O]降至(17～20)×10-6,铸坯总氧含量为(11～15)×10-6.铸坯中主要为≤3 μm的球状、块状Al2O3和Al2O3-MnS复合夹杂.≥50μm的大型夹杂物最高含量为5.18 ms/10kg.     

Vitrification and Crystallization Behavior of CaO-SiO2-MgO-Al2O3-Fe2O3-Cr2O3 System

Metallurgical and Materials Transactions B - The effect of basicity and Cr2O3 content on vitrification of the CaO-MgO-SiO2-Al2O3-Fe2O3-Cr2O3 system during a melt-quenched process and the...     

Viscosity of CaO-SiO2-Al2O3-MgO-B2O3 slags

The viscosity of CaO-SiO₂-Al₂O₃ slags with 8% MgO and 4% B₂O₃ is investigated over a broad range of composition, by means of a simplex-lattice experiment design. For slag of basicity 6–8 in the upper left region of the local simplex, with 15–25% Al₂O₃, 8% MgO, and 4% B₂O₃, the viscosity is high: 9.4–26.4 P over the range 1500–1530°C. Displacement of the slags of basicity 5–8 to the lower region of the local simplex ensures high fluidity in the given range of Al₂O₃ concentration: the viscosity is 1.5–6.1 P over the range 1500–1530°C.     

Gd_2O_3-Yb_2O_3-Y_2O_3-ZrO_2热障涂层材料及涂层性能研究

使用化学共沉淀法合成了纳米Gd2O3-Yb2O3-Y2O3-ZrO（2GYYZO）粉末,并最终制备了超细晶团聚的多元稀土氧化物掺杂的GYYZO热喷涂粉末,系统的研究了材料及涂层的基本性能,重点研究了材料及涂层的高温稳定性,材料和涂层的高温相稳定性相对传统纳米8YSZ材料明显提高,对高温热处理过程中涂层孔隙收缩、晶粒长大...     

Research on Glass Forming Ability of Er2O3 -Al2O3 -B2O3 -SiO2 System

The glass forming range of Er2O3-Al2O3-B2O3-SiO2 system was explored, and the effect of the content of Al2 O3 and Er2 O3 on glass-forming region was experimentally examined. It is shown that the region of glass formation range expends when the content of Al2O3 is changed from 15% to 20%, while it shrinks when the content of Er2O3 is changed from 20% to 30%. At the same time, the glass forming ability of Er2O3-Al2O3-B2O3-SiO2 system was also discussed using a value of β, which is an indication of crystallization tendency of glasses, calculated from thermo-analysis data. It is found that the glass forming ability of Er2O3-Al2O3-B2O3- SiO2 glasses is poor, while the glasses network may be enhanced when Al2O3 is added to the system, the glass forming ability being heightened. In addition, the crystallization temperatures of the rare earth glasses were determined using differential thermal analysis technique. The Er2O3-Al2O;-B2O3-SiO2 glass samples were heat treated at 1000,1100 and 1260℃ respectively. The results show that it is the Er2O3 phase that separates out from the glasses after crystaline heat treatment, and it is tiered up in glasses, as detected through XRD and SEM. This indicates that the phase separation occurs when the glasses are heated, Er3 being mainly distributed in the boron rich phase, then separated out from glasses, while the silicate rich phase remaining glassy state.     

CaO-La2O3-B2O3-Eu2O3转光玻璃的合成及荧光性质

X射线衍射研究表明CaO-La2O3-B2O3-Eu2O3体系的玻璃化温度在1025℃附近。荧光光谱和ESR谱研究表明,在CaO-La2O3-B2O3-Eu2O3玻璃体系中存在着Eu2 和Eu3 两种价态离子。316,360,379,394,413,462和532nm锐线激发峰和592,616和650红区发射峰分别对应Eu3 的f-f激发跃迁和5D0-7FJ(J=1,2,3)跃迁发射;351nm和427nm宽带激发峰和蓝区发射分别对应Eu2 的5d-4f激发跃迁和发射。     

镁砂中Fe2O3、Al2O3、P2O5、TiO2的联合测定

镁砂产品检验中,采用碱熔融法共同预处理样品,在同一母液中,联合测定铁、铝、磷、钛的含量,缩短了检测时间。通过分别控制各元素的显色酸度,各元素线性良好,测得的Fe2O3、Al2O3、P2O5、TiO2的相对标准偏差分别小于1.11%、2.78%、4.84%、5.88%。实验结果表明,方法的准确度和精密度都较高。     

Wettability of silicon carbide ceramic by Al2O3/Dy2O3 and Al2O3/Yb2O3 systems

Wettability is an important phenomenon in the liquid phase sintering of silicon carbide (SiC) ceramics. This work involved a study of the wetting of SiC ceramics by two oxide systems, Al₂O₃ /Dy₂O₃ and Al₂O₃ /Yb₂O₃, which have so far not been studied for application in the sintering of SiC ceramics. Five mixtures of each system were prepared, with different compositions close to their respective eutectic ones. Samples of the mixtures were pressed into cylindrical specimens, which were placed on a SiC plate and subjected to temperatures above their melting points using a graphite resistance furnace. The behavior of the melted mixtures on the SiC plate was observed by means of an imaging system using a CCD camera and the sessile drop method was employed to determine the contact angle, the parameter that measures the degree of wettability. The results of variation in the contact angle as a function of temperature were plotted in graphic form which showed that the curves displayed a fast decline and good spreading. All the samples of the two systems presented final contact angles of 40° to 10° indicating their good wetting on SiC in the argon atmosphere. The melted/solidified area and interface between SiC and melted/solidified phase were evaluated by scanning electron microscopy (SEM) and their crystalline phases were identified by X-ray diffraction (DRX). The DRX analysis showed that Al₂O₃ and RE₂O₃ reacted and formed the Dy₃Al₅O₁₂ (DyAg) and Yb₃Al₅O₁₂ (YbAg) phases. The results indicated that the two systems had a promising potential as additives for the sintering of SiC ceramics.     

Optical Spectroscopy of Er^3＋ and Er^3＋/Yb^3＋ Co-doped Bi2O3-GeO2-B2O3-ZnO Glasses

The （60 - x）Bi2O3 - xGeO2-30B2O3-10ZnO （x = 5, 10, 20, 30 molar percent） glasses doped with Er^3＋ and Er^3＋/Yb^3＋ were fabricated using the melting method. The thermal stability of the glasses was studied with their DTA curves. The results show that the difference between the glass transition temperature and the crystallization onset temperature increases with the increase of GeO2 content, indicating that the thermal stability of the glass has become better. The absorption spectra were recorded and the stimulated emission cross sections were calculated using the McCumber theory. The Ω2, O4, and Ω6 parameters,the transition probability, the radiative lifetime, and the fluorescence branch ratio of Er^3＋ for optical transition were calculated from their absorption spectra in terms of reduced matrix U^（t）（λ = 2, 4, 6） character for optical transitions. The infrared emission of Er^3＋ was measured upon excitation with 970 nm light and the full width at half-maximum （FWHM） was estimated from the emission spectra. The pumping efficiency and the intensity of the emission at the 1.54 μm band of Er^3＋ were enhanced considerably by co-doping Yb^3＋ .