141 resultados para 7038-507
Resumo:
溶剂分馏萃取是分离、提纯、富集物质的有效方法之一,由于它具有分离效果好,易于操作等优点。因此,在稀土萃取分离工艺中得到了广泛的应用。但是,每个分馏萃取工艺只能分离两个组份,若要分离所有稀土元素,流程较长。为改进生产,本工作提出了一种三出口萃取分离工艺流程。这种工艺流程可视为由两个萃取段和两个洗涤段组成,由于在两个洗涤段中,两相稀土浓度较高、稀土交换量较大,故可使级数减少。采用此工艺流程进行了P_(507)萃取分离Gd、Tb、Dy三组元素的串级模拟实验,得到了纯度大于99.99%的La-Gd,纯度大于99.8%的Dy-Lu和含量高于65%的Tb_4O_2富集物。Tb的收率大于95%。串级总级数为38级。通过对P_(507)萃取实际体系中稀土元素行为的研究,建立了多元体系中稀土在两相分配的经验模型。Z=C_1H~(C2)×T~(C_3)e~(c_4X(Tb)+C_5X(Dy))和具有一定物理意义的半热力学半经验模型。YT=(Z/H)~3[Σ from i=1 to m of CiXi + Co]根据氨化P_(507)萃取工艺中稀土总浓度在两相的分布规律,提出了一种适合氨化P_(507)萃取分离多元混合稀土工艺的串级计算方法,并用FORTRAN语言编写 了计算程序。使用自编的计算程序进行了氨化P_(507)萃取分离Gd、Tb、Dy三出口工艺的串级模拟计算,计算结果与实验值基本一致。同时,对文献中报导的中间某级开设出口的一分三工艺也进行了串级计算,根据计算结果讨论了两种工艺的优缺点。对恒定混合萃取比的多元稀土萃取分离工艺,进行了在不同串级条件下分界元素在各级的积累及易萃组份和难萃取份的有效分离系数在各级变化规律的计算。结果表明,有效分离系数在级体中出现一极小值β~*,并且β~*值的大小与其出现在级体中的位置随条件不同而改变。对同一萃取体系,当出口产品较纯时,用线性回归分析法关联计算数据得到了β~*与出口产品组成和总萃取比的经验关系式,在萃取段有(A、B与C分离的工艺)β~*/β_B~C=C1+C2EM+C_3ln (A1)/(B1)引入有效分离系数后,进行了环烷酸萃取分离钇与镧系元素的串级模拟计算,计算结果与实验值基本吻合。
Resumo:
The oxovanadium phosphonates (VO(P-204)(2) and VO(P-507)(2)) activated by various alkylaluminums (AlR3, R = Et, i-Bu, n-Oct; HAIR(2), R = Et, i-Bu) were examined in butadiene (Bd) polymerization. Both VO(P-204)(2) and VO(P-507)(2) showed higher activity than those of classical vanadium-based catalysts (e.g. VOCl3, V(acac)(3)). Among the examined catalysts, the VO(P-204)(2)/Al(Oct)(3) system (I) revealed the highest catalytic activity, giving the poly(Bd) bearing M-n of 3.76 x 10(4) g/mol, and M-w/M-n ratio of 2.9, when the [Al]/[V] molar ratio was 4.0 at 40 degrees C. The polymerization rate for I is of the first order with respect to the concentration of monomer. High thermal stability of I was found, since a fairly good catalytic activity was achieved even at 70 degrees C (polymer yield > 33%); the M-n value and M-w/M-n, ratio were independent of polymerization temperature in the range of 40-70 degrees C. By IR and DSC, the poly(Bd)s obtained had high 1,2-unit content (> 65%) with atactic configuration. The 1,2-unit content of the polymers obtained by I was nearly unchanged, regardless of variation of reaction conditions, i.e. [Al]/[V], ageing time, and reaction temperature, indicating the high stability of stereospecificity of the active sites.
Resumo:
The catalyst system neodymium phosphonate Nd(P-507)(3)/H2O/Al(i-Bu)(3) for the polymerization of styrene was examined. Effects of the addition order of the catalyst components, catalyst aging time and aging temperature on the catalyst activity and the polymer characteristics were investigated. The catalyst activity for isospecific polymerization of styrene increases with aging time and reaches the maximum with a catalyst aged for 45 min at 70 degrees C. The aging time that the catalyst needs to reach the highest activity for isospecific polymerization decreases with increasing aging temperature. The preformed catalyst and the in situ catalyst were compared with respect to the kinetic behavior of the styrene polymerization and the polymer characteristics.
Resumo:
通过实验,研究了2-乙基已基膦酸单(2-乙基已基)酯,在盐酸介质中萃取铅的规律和机理,为荧光级稀土生产提供了理论依据。
Resumo:
本采用萃取色谱法,以P507萃淋树脂为固定相,以HCl-NH4Cl体系为淋洗液,研究了高纯Nd2O3(99.999%~99.9999%)中稀土杂质与Nd基体的分离方法。选择螯合剂-活性碳柱富集淋洗液中痕量稀土,采用火花源质谱法分析,测定下限0.01μg/g。
Resumo:
本文采用萃取色谱法以P507萃淋树脂为固定相,以HCl-NH4Cl体系为淋洗液,研究了高纯Er2O3(99.999%~99.9999%)中稀土杂质和Er基体的分离方法,并选择了富集方法和火花源质谱测定条件,达到了纯度为99.9999%的超纯Er2O3的分析要求。
Resumo:
本文采用萃取色谱法,以P507萃淋树脂为固定相,以HCl-NH4Cl体系为洗脱液,研究了99.999%~99.9999%高纯Gd2O3中稀土杂质和Gd基体的分离方法,并选择了富集方法和火花源质谱测定条件,达到了纯度为99.9999%的高纯Gd2O3的分析测定要求
Resumo:
研究了P_(507)从HNO_3体系和HCl体系萃取重稀土Er、Tm、Yb、Lu的规律。从HNO_3体系中萃取,不论是单一组份或者多元混合组份,很快达到平衡。但从HCl体系中萃取,平衡缓慢,萃取单一稀土时温度、水相稀土浓度和酸度对平衡时间都有明显影响,萃取多元混合稀土时即使是在稀土浓度较高而酸度较低的情况下萃取平衡亦是相当缓慢的。HCl体系中Cl增加对平衡时间无明显影响,而加入少量NO_3~-离子不论是单一或者多元混合稀土体系,萃取平衡时间大大缩短。
Resumo:
证明了含任意切口、任意切口边界的多材料中厚扁壳问题的特征根等于相应的平面切口问题和平板弯曲切口问题两部分的特征根组合。进而证明了中厚扁壳切口问题的特征根等于相应反平面切口问题和平面切口问题的组合。中厚扁壳切口问题的特征根及其对应的0级特征函数均可直接按相应的两类基本问题(反平面切口问题和平面切口问题)进行求解。
Resumo:
本文介绍了3cm微波透射仪用来测量激波管中电子密度的工作原理,给出了φ800mm激波管中电子密度随M数的变化规律,测量数据与其他测量方法所得结果是一致的,与理论计算的预计也是一致的。
Resumo:
用高速干涉摄影诊断手段对激光作用在固体靶材上的表面效应,冲击波的传播、反射及绕射机制进行了实验观察,拍摄了各种现象的干涉及阴影照片,并进行了简要的分析。
Resumo:
用高速干涉摄影诊断手段对激光作用在固体靶材上的表面效应,冲击波的传播、反射及绕射机制进行了实验观察,拍摄了各种现象的干涉及阴影照片,并进行了简要的分析。
Resumo:
This paper deals with the interaction of solitary waves in a two-fluid system which consistsof two superimposed incompressible inviscid fluids with a free surface and a horizontal rigidbottom. Under the assumption of shallow water wave, we first derive the basic equationssuitable for the model considered, a generalized form of the Boussinesq equations, then usingthe PLK method and the reductive perturbation method, obtain the second-order approximatesolution for the head-on collision between two pairs of interface and surface solitary waves,and give their maximum amplitudes during the collision and the nonuniform phase shiftsafter the collision which lead to the distortion of the wave profiles.