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1.
对低富集比钽铌产品及长石产品中的目的元素如何进行金属平衡作了全面论述, 以实例方式对(Ta, Nb)2O5与Fe2O3的金属平衡进行计算, 对其他类似实验数据及日常生产检测数据的处理具有参考价值。   相似文献   

2.
采用自制的相平衡研究装置,测定了Rb2CO3-PEG-H2O三元体系在25,35,45℃ 3个温度及PEG1000,4000,10000 3个分子量下的等温平衡溶解度。用四参数方程w1=a+bw2^0.5+cw2+dw2^2对体系的双液线进行了拟合,拟合结果较好。结果表明该体系的双液相区,随着体系温度的升高和聚乙二醇分子量的增加而增大。用Othmer-Tobias方程和Bancroft方程对体系结线的实验数据进行了关联,并给出了方程的参数,所有线性相关系数(R)均大于0.99;并用NRTL模型对其进行了拟合。论文给出的Rb2CO3-PEG-H2O三元体系的相平衡数据,不仅为溶液化学提供了基础热力学数据,而且为碳酸铷的分离纯化及生物物质的萃取提供了新的方法和依据。  相似文献   

3.
周勇 《四川冶金》2011,33(6):22-26
根据熔渣结构的分子离子共存理论建立了CaO-SiO2-Al2O3-V2O3四元系活度模型,应用该模型计算出的活度数据,对用钒氧化物矿代替钒铁直接合金化冶炼高速钢的工艺过程进行了热力学计算和分析.用此活度数据计算了Al作还原剂时渣的平衡成分,计算结果表明渣中V2O3的含量极低,直接合金化的热力学条件好,钒理论最大还原率高.通过该活度数据计算钢中或渣中的各种还原剂还原渣中V2O3的△G和Lv,计算结果表明Al是所有还原剂中还原能力最强的.  相似文献   

4.
本研究采用高温氧化的方法制备出纳米NiAl2O4/Al2O3粉体。在纳米Al2O3粉体表面包覆一层金属Ni,在1350℃高温下焙烧Ni/Al2O3复合粉体得到纳米NiAl204/Al2O3粉体。利用TEM对Ni/Al2O3复合粉体进行观察,发现Ni/Al2O3复合粉体颗粒成球形,大小为50~60nm;通过对Ni/Al2O3复合粉体的DTA析,显示Ni/Al2O3复合粉体在900℃和1300℃下有新相生成,经XRD检测,新相分别为NiO和NiAl2O4。  相似文献   

5.
应用有关热力学数据,对Ni-NH3-H2O系的水解平衡进行了理论计算,绘制了在不同总氨浓度下的Ni-NH3-H2O系热力学loga-pH状态图。loga-pH状态图揭示了氨浓度及pH对Ni(OH)2溶解度影响的热力学规律,随着氨浓度的增加,Ni(OH)2溶解度增加。研究结果为中和水解法处理镍氨废水提供了理论依据。  相似文献   

6.
In2S3-H2O系电位-pH图   总被引:1,自引:0,他引:1  
通过热力学计算,给出了In2S3-H2O系的反应平衡式及电位-pH的关系式,并绘制了25 ℃和150 ℃下In2S3-H2O系的电位-pH图,为含硫化铟的矿物高温氧化浸出提供了一定的热力学数据.  相似文献   

7.
应用同时平衡原理和质量平衡原理对SnCl4-NH4Cl-HCl-H2O体系进行了热力学分析和计算,对于无法收集的相关(NH4)2SnCl6的热力学数据进行了估算,在此基础上绘制了SnCl4-NH4Cl-HCl-H2O体系在标准状态下各相关物种和pH之间的关系曲线。结果表明,溶液中的总铵浓度和体系的pH值是影响(NH4)2SnCl6或Sn(OH)4存在的重要参数。在该体系中,增大体系的酸度到6nol/L以上,体系中的Sn^4 既以(NH4)2SnCl6形式沉淀出来,这就为直接由含锡原料提取纯(NH4)2SnCl6,并用以取代SnCl4来制备ATO或ITO粉体提供了理论依据。  相似文献   

8.
Ni、Cu-Al2O3纳米金属陶瓷粉末的热压   总被引:5,自引:0,他引:5  
将化学电镀法制备的纳米Ni、Cu包覆Al2O3粉末进行热压。研究了金属Ni、Cu及其含量对Al2O3粉末的烧结致密化、显微组织和性能的影响。在纳米Al2O3粉末表面镀覆适当的金属Ni、Cu可以较有效地提高致密化,降低烧结温度。金属相作为第二相可以大大细化Al2O3晶粒组织。但Ni、Cu的加入伴随着Al2O3硬度和强度下降。硬度变化可以由金属Ni、Cu是软相较好地解释。强度下降则主要归因于包覆粉末中Ni、Cu对Al2O3粉末的润湿性不好所致。  相似文献   

9.
Ta2O5直接制备金属钽的研究   总被引:1,自引:0,他引:1  
利用固体透氧膜(SOM)法对Ta2O5直接电解制备金属钽进行了研究。Ta2O5粉经压片烧结后制成阴极,氧化钇稳定氧化锫管内的碳饱和铜液为阳极,混合熔盐MgF2-CaF2为电解质,在1150℃不同电压下进行电解。经XRD,SEM等分析表明:在透氧膜稳定的条件下,电压越高,脱氧速度越快。该方法制备金属钽具有电解速度快、电流密度高等优点,发展前景良好。  相似文献   

10.
采用高温氧化的方法制备出纳米NiAl2O4圈层包覆Al2O3粉体.在纳米Al2O3粉体表面包覆一层金属Ni,在1 350℃高温下焙烧Ni/Al2O3复合粉体得到纳米NiAl2O4圈层包覆Al2O3粉体.利用TEM对Ni/Al2O3复合粉体进行观察,发现Ni/Al2O3复合粉体颗粒呈球形,大小为50~60 nm;Ni/Al2O3复合粉体的DTA分析结果表明,Ni/Al2O3复合粉体在900和1 300℃时有新相生成,经XRD检测,新相分别为NiO和NiAl2O4.  相似文献   

11.
Metallurgical and Materials Transactions B - B2O3 and Na2O are key components of fluorine-free mold fluxes for continuous casting, but both are highly volatile, which affects the flux stability....  相似文献   

12.
Conclusions Using the techniques of DTA and x-ray phase analysis, a study was made of the reactions between Ta2O5 and M2O3 (M = Ga or In), and the phase compositions of the relevant binary systems were determined. The existence was confirmed of stable compounds of composition MTaO4 and eutectoidally decomposing phases containing 7.5–12.5 mole % M2O3. MTaO4 are dielectrics, whose room-temperature v is of the order of 1010 -cm. The temperature dependence of v of MTaO4 was investigated in the range 293–873°K and their energies of activation for conductivity were calculated. The melting points, pyknometric densities, dielectric losses, and relative dielectric permeabilities of MTaO4 were determined.Translated from Poroshkovaya Metallurgiya, No. 2 (110), pp. 69–73, February, 1972.  相似文献   

13.
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...  相似文献   

14.
CaO-La2O3-B2O3-Eu2O3转光玻璃的合成及荧光性质   总被引:3,自引:2,他引:3  
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。  相似文献   

15.
The influences of Al2O3/CaO and Na2O/CaO ratios on viscosities of CaO-Al2O3-SiO2-Na2O melts are investigated by the rotating cylinder method in this study. It is indicated from the experimental results that viscosity first increases and then decreases as gradually increasing Na2O/CaO ratio. As increasing Na2O/CaO ratio while keeping the contents of Al2O3 and SiO2 constant, the transformation of bridging oxygen (from being bonded with Al3+ ion charge compensated by Ca2+ ion to that compensated by Na+ ion, for the higher priority of Na+ ion relative to Ca2+ ion) increases the viscosity, whereas the transformation of non-bridging oxygen decreases the viscosity. These two factors lead to the appearance of viscosity maximum. The viscosity model proposed in our previous papers could well describe the viscosity variation tendency.  相似文献   

16.
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.  相似文献   

17.
Metallurgical and Materials Transactions B - The present study investigated the influences of Na2O and K2O additions on electrical conductivity of blast furnace type CaO-MgO-Al2O3-SiO2 melts by the...  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
Li2O对CaO-SiO2-MgO-Fe2O3-MnO2-P2O5精炼渣系脱磷的影响   总被引:2,自引:1,他引:1  
李桂荣  王宏明 《特殊钢》2002,23(2):14-16
在Li2 O替代CaO SiO2 MgO Fe2 O3 MnO2 P2 O5精炼渣系中部分CaO的条件下 ,研究了Li2 O含量、碱度及氧化性对钢液磷含量的影响。结果表明 ,在Li2 O =15 % ,碱度 (CaO +Li2 O) /SiO2 为 2 .0~ 2 .5 ,(Fe2 O3 +MnO2 )为 7%的条件下 ,该渣系对钢液的脱磷率在 70 %以上 ,控制钢液磷含量在 0 .0 0 9%以下。  相似文献   

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