多向观测电感耦合等离子体原子发射光谱法同时测定碳酸盐中11种组分

采用盐酸、硝酸、高氯酸和氢氟酸溶解试样,在0.63 mol/L的硝酸介质中,选择信背比大,干扰少的光谱线作分析线,通过径向衰减观测方式测定Al,Fe,Ca,Mg,K,Na,P,Ti元素,轴向方式测定Si,Mn,S元素,实现了电感耦合等离子体原子发射光谱法测定碳酸盐中SiO2,Al2O3,Fe2O3,CaO,MgO,K2O,Na2O,P2O5,TiO2,MnO,SO311种组分。主量元素Ca对其他元素的测定有抑制作用,采用基体匹配方法可消除,其他元素间的相互干扰很小,对测定没有影响。用本法测定了石灰岩和白云     

反相色层分离电感耦合等离子体原子发射光谱法测定可燃毒物(Gd,U)O_2中12种微量元素

采用磷酸三丁酯-聚偏氟乙烯反相分配色层分离法使Al,Ca,Co,Cr,Fe,Mg,Mn,Mo,Ni,Sn,Ti,V,Gd与U分离,用电感耦合等离子体原子发射光谱法测定Al,Ca,Co,Cr,Fe,Mg,Mn,Mo,Ni,Sn,Ti和V 12种元素,大量Gd不干扰。取样100 mg时,测定范围为20~640μg/g。方法已用于可燃毒物(Gd,U)O2中上述12种微量元素测定。回收率在94%~110%之间,相对标准偏差(RSD)为4.6%~9.2%。     

低碳含铝钢20Mn2精炼渣系CaO-SiO2-Al2O3-MgO-CaF2的优化

通过对低碳含铝钢20Mn2精炼过程的取样分析,得出精炼渣的熔化温度偏高,渣中存在大量固相Ca O,并导致钢中含有Ca O类夹杂物,精炼渣吸附夹杂物能力差.利用Fact Sage热力学计算,从渣的低熔点区域控制和渣-钢反应这两个方面对渣系进行研究与优化.结果表明,Ca O/Al2O3质量比在1.5左右添加质量分数为3%Ca F2可以有效降低渣的熔化温度,渣的熔化温度随着Ca F2含量的升高呈现先降低后升高的趋势,Mg O的质量分数控制5%左右低熔点区域面积达到最大.在Si O2质量分数大于30%区域,钢中氧含量大体上随着Ca O/Al2O3质量比的增加而降低,在Si O2的质量分数低于30%区域随着Ca O含量的升高而降低,钢中酸溶铝含量在Si O2含量高的区域随着Al2O3/Si O2质量比的增加而升高,在Si O2含量低的区域随着Ca O/Si O2质量比的增加而增加.根据热力学分析结果得出合理的渣系范围:Ca O 50%~60%,Al2O320%~35%,Si O25%~10%,Mg O 5%~8%,Ca F20~5%.优化渣系的实验结果表明,优化后渣系熔化温度降低,钢中夹杂物数量、面积和平均尺寸均有明显下降.     

《原子吸收法测定硅酸盐岩石和铝钒土中的成岩元素》

本文目的是拟定硅酸盐矿石和铝钒土中测定 Si、Ti、Al、Fe、Ca、Mg 和 Mn 的原子吸收方法。原子吸收法使用日立207型单光束原子吸收光谱仪。该仪器的特点是光束两次通过火焰,光线几乎全部通过火焰中心部分。根据数据判断,Fe、Mg 和 Mn 的检出极限用 C_2H_2/Air 火焰比用 C_2H_2/N_2O 火焰要高1—9倍。这可解释为这些元素在 C_2H_2/Air 火焰中得到充分原子化,稳定性比较好。Si、Al 和 Ti 实际上只能应用 C_2H_2/N_2O 火焰进行测定。利用富燃的 C_2H_2/N_2O 火焰,     

电感耦合等离子体原子发射光谱法测定煤与焦炭中18种元素

采用电感耦合等离子体原子发射光谱(ICP-AES)法直接测定煤与焦炭中Si,P,Al,V,Cr,Cd,Pb,Cu,Co,Ni,Zn,K,Na,Fe,Ca,Mg,Mn,Ti 18种元素。样品被灰化后取一定量灰样,用氢氧化钠熔融,热水和盐酸浸取,溶液用于测定Si和P,得到煤或焦炭灰中Si,P含量。另取灰化后的全部灰样,用高氯酸和氢氟酸溶解并加热至赶尽高氯酸,用稀硝酸溶解,溶液用于测定Al,V,Cr,Cd,Pb,Cu,Co,Ni,Zn,K,Na,Fe,Ca,Mg,Mn和Ti,得到煤或焦炭中16个元素含量。Si和     

原位生成陶瓷相增强铝基复合材料物相组成和反应机制的研究

通过外加颗粒SiO2 采用粉末冶金法成功制备了原位生成陶瓷相增强Al基复合材料 ,定量研究了复合材料的物相组成和反应机制。主要反应方程式为颗粒内Al 1/ 2Mg SiO2 =1/ 2MgAl2 O4 Si和颗粒外 2Mg Si=Mg2 Si。最终物相由约为 16.5 %～ 18.4%MgAl2 O4 ,3 %～ 5 %Si,11.7%Mg2 Si,及大于 0 .5 2 %MgO ,其余为Al组成 ,约 7%Al参加了反应 ,Mg和SiO2 基本消耗尽。反应是以SiO2 颗粒为核心进行的。这种反应及元素的扩散可以用“逐层反应机制”和“元素微观通道扩散机制”来描述。     

X射线荧光光谱法直接测定茶叶中22种元素

拟定了采用粉末样品压片制样 ,利用X射线荧光光谱仪测定茶叶中 2 2种元素 (Al,As,Ba ,Ca,Cl,Co ,Cr,Cu ,Fe,K ,Mg ,Mn ,P ,S ,Si,Sr,Pb ,Ni,Ti,V ,Zn ,Rb)的方法。应用X40软件中的PHILIPS数学模式对基体效应、元素间的谱线重叠干扰等作了有效的校正。本方法可用于茶叶中多元素同时测定     

电感耦合等离子体原子发射光谱法测定钨产品中痕量杂质元素

采用在密闭塑料瓶中硝酸、氢氟酸常温常压分解样品,系统分析了样品中痕量杂质元素V、Ti、Mo、Fe、Sb、Pb、As、Co、Mg、Ca、Mn、Al、Sn、Na、K、Ni、Cr、Cd、Si、Cu、P、Bi的光谱干扰情况及钨酸沉淀分离基体后各元素的回收率情况,最终确立了电感耦合等离子体原子发射光谱(ICP-AES)法测定钨产品中痕量元素的方法。V、Ti由于基本不受基体干扰,钨酸沉淀分离基体后回收率较低,采用在校准曲线中补加基体的方法对其进行测定,其中V的测定下限为5.2μg/g,Ti的测定下限1.3μg/g：Co、Mg、Ca、Mn、Al、Na、K、Ni、Cr、Cd、Si、Cu、Pb、Sn、As、Sb、Bi等元素,受钨基体干扰比较严重,采用钨酸沉淀分离基体后,回收率均在90.0%以上,故采用沉淀分离基体,水标直接测定,各元素的测定下限均在0.10～6.7μg/g之间：而对于受钨基体严重干扰,而且钨酸沉淀分离基体后回收率较低的Fe、Mo、P3元素,目前没有很好的解决方案。此方法为解决钨产品中痕量杂质元素测定提供了一种有效可行的方法。     

Y对原位Mg2Si/Al基复合材料初生相Mg2Si的细化机制

选用稀土Y和采用普通重力铸造法制备原位自生Mg2Si/Al基复合材料,研究不同含量的稀土Y对初生相Mg2Si形貌、尺寸和力学性能的改变.结果表明:稀土Y对Mg2Si/Al复合材料的凝固组织有影响;添加Y处理的Mg2Si/Al基复合材料的Mg2Si颗粒变得更加细小;通过计算二维错配度,发现Y可以作为初生相Mg2Si的异质形核质点从而细化颗粒,同时Y与Al相互作用形成Al3Y相可阻止Mg2Si相长大;此时铸态Mg2Si/Al合金复合材料的力学性能得到改善,其最大抗拉强度和延伸率分别为144 MPa和4.19％.     

Effect of SiO2 substitution with Al2O3 during high-Al TRIP steel casting on crystallization and structure of low-basicity CaO–SiO2-based mold flux

The crystallization and structure of non-conventional lime-silica-based mold fluxes after undergoing slag-steel interaction in casting high-AI transformation induced plasticity(TRIP)steel were studied.The results showed that the crystallization temperatures of the mold fluxes decreased with decreasing the SiO2/Al2O3 ratio,and CaO/MnO2 ratio had an opposite effect on the crystallization temperatures.The crystalline phases precipitated in the mold flux were Ca4Si2O7F2 and NaAlSiO4.Decreasing SiO2/Al2O3 ratio and increasing CaO/MnO2 ratio in the mold fluxes have no influence on the types of crystalline phases.The dominant crystalline phase precipitated in each mold flux was Ca4Si2O7F2 with dendritic morphology,except for part of that with globular morphology in the mold flux without MnO2 addition.NaAlSiO4 crystals are distributed in the space among Ca4Si2O7F2 crystals.The size of Ca4Si2O7F2 crystals in the slag with higher S1O2/AI2O3 ratio is smaller,which is attributed to the polymerization degree of the mold flux with increasing SiO2/Al2O3 ratio.[SiO4]-tetrahedral,[AlO4]-tetrahedral and T-O-T bending(T denotes Si or Al)depolymerized gradually with decreasing SiO2/Al2O3 ratio,and an opposite trend was observed for the case with increasing CaO/MnO2 ratio.The polymerization degree of the mold fluxes decreased,which would result in the decrease in the viscosity of the mold fluxes.     

X射线荧光光谱法测定矾土中硅、铁、钾、钙、钛、锰、铝、镁、磷等氧化物含量

建立了X射线荧光光谱法测定矾土中硅、铁、钾、钙、钛、锰、铝、镁、磷等氧化物的方法。以四硼酸锂做熔剂、溴化锂做脱模剂制备玻璃熔片 ,以标准物质和高纯试剂制备标准片做校正曲线 ,并对吸收增强效应和光谱重叠做出校正。通过测定标准样品进行比较 ,本法没有显著性差异。回收率为 86.7%～ 10 6.2 %。     

Critical evaluation and optimization of the thermodynamic properties and phase diagrams of the MnO-TiO2, MgO-TiO2, FeO-TiO2, Ti2O3-TiO2, Na2O-TiO2, and K2O-TiO2 systems

All available thermodynamic and phase diagram data have been critically assessed for all phases in the MnO-TiO₂, MgO-TiO₂, FeO-TiO₂, Ti₂O₃-TiO₂, Na₂O-TiO₂, and K₂O-TiO₂ systems at 1 bar pressure from 298 K to above the liquidus temperatures. All reliable thermodynamic and phase diagram data have been simultaneously optimized to obtain, for each system, one set of model equations for the Gibbs energy of the liquid slag as a function of composition and temperature and equations for the Gibbs energies of all compounds as functions of temperature. The modified quasichemical model was used for the molten slag phases.     

Nitrogen solubility in CaO-SiO2, CaO-MgO-SiO2, and BaO-MgO-SiO2 melts

Nitrogen solubility in molten CaO-SiO₂, CaO-MgO-SiO₂, and BaO-MgO-SiO₂ silicate systems was measured as functions of nitrogen and oxygen partial pressures and composition at 1823 K. Experimental findings indicate that nitrogen exists as a free nitride ion or is associated with silicate networks, depending principally on the slag composition. A special analytical technique was developed to separately determine the two species. Its dissolution mechanism, which is similar to that for hydrogen, was proposed, being supported by the detection of a Si-N bond by infrared spectroscopy. Neither the content of free nor incorporated nitrogen was demonstrated to have a very good correlation with the CaO or SiO₂ activity in the melts, probably because the activity coefficient of nitrogen is affected by the slag composition. Formerly Graduate Student, Department of Metallurgy, The University of Tokyo.