还原硅钼酸盐分光光度法测定偏钒酸铵中硅的含量

介绍了还原硅钼酸盐分光光度法测定偏钒酸铵中的硅含量 ,讨论了吸收波长、还原剂、酸度及掩蔽剂加入量等因素对测定结果的影响。结果表明 ,还原硅钼酸盐分光光度法测定偏钒酸铵中的硅含量 ,数据准确     

钼-锑-抗分光光度法测定水中黄磷方法的改进

通过对目前使用的钼-锑-抗分光光度法测定水中黄磷的方法进行优化,将实验条件确定为:氧化剂溴水的用量为3 m L,将已经加入溴水并盛有环己烷相的比色管置于沸水浴中,加热20～30 min至无色时,才可使氧化反应基本完成,测量吸光度前利用分液漏斗将环己烷相从水相中分离并弃去。检测结果表明,在改进实验条件下,黄磷含量在0～82μg呈现良好的线性关系,相关系数0.999,相对标准偏差0.47%～1.7%,加标回收率92.6%～103.3%,实验结果更准确、实验过程更容易操作。该法可以用于地表水中黄磷的测定。     

分光光度法测定钴—钼废催化剂中钼的研究

研究了在还原剂存在下硫氰酸钾与钼的显色反应。发现硫脲存在下，钼与硫氰酸钾在１．５～２ｍｏｌ硫酸溶液中形成橙红色络合物，其最大吸收峰位于４６０ｎｍ处，表观摩尔吸收系数１８．５×１０３Ｌ·ｍｏｌ－１·ｃｍ－１。钼浓度与钼络合物的吸光度在０～２０ｍｇ／ｍｌ范围内有良好的线性关系。     

分光光度法测定钼精矿中磷

采用王水 氢氟酸 高氯酸溶矿,以5%的HCl浸取,用磷锑钼蓝分光光度法测定钼精矿中的磷。     

矿石中钼的测定方法的比较

结合几种对矿石中钼的测定方法的比较,给出了各个方法的适用范围,为钼的测定提供了理论依据,并对实际工作中存在的问题提供了积极的参考价值。     

盐酸联氨还原亮甲酚蓝催化光度法测定痕量钼

基于钼（Ⅵ）催化盐酸联氨还原亮甲酚蓝反应，拟定了测定痕量钼的新催化光度法。在不同温度条件下，可测钼含量范围为０．０２５～０．６０μｇ／ｍｌ，方法检出限为９．６×１０－９ｇ／ｍｌ，用于测定豆类中痕量钼。     

分光光度法测定钴—钼废催化剂中钼的研究

研究了在还原剂存在下硫氰酸钾与钼的显色反应。发现硫脲存在下，钼与硫氰酸钾在１．５－２ｍｏｌ硫酸溶液中中形成橙红色络合物，其最大吸收峰位于４６０ｎｍ处，表观摩尔吸收系数１８．５×１０＾３Ｌ．ｍｏｌ＾－１，ｃｍ＾－１。钼浓度与钼络俣物的吸光度在０－２０ｍｇ／ｍｌ范围内有良好的线性关系。     

硫氰酸盐光度法测定钼的影响因素探讨

对硫氰酸盐光度法测定钼时的误差和显色时间、显色温度等影响因素进行了分析和探讨。得到该方法准确测定的条件为:显色温度20℃,显色时间15 min,测定时间≤2 h。     

钼铁中钼的测定

本文介绍,评定测定钼铁合金中钼的光度法,认为该法操作简便,费时短,准确度高,而优于一般的重量法。     

利用钼矿尾砂制低温铁炻器

以钼矿尾砂为主体原料,以Fe2O3为主要复合低温熔剂研制成功了符合国标GB3532-94要求的日用铁炻器产品。     

磷化液中钼的分光光度法测定

采用硫氰酸盐为显色剂的分光光度法,直接测定在磷化液中以钼酸盐作为磷化加速剂里的钼,采用弱还原剂硫脲,用铜盐催化加快显色速度,用Fe2 为显色液的稳定剂,生成的橙红色配合物。经试验测定钼在50～300μg范围内,符合比耳定律。λmax=460 nm;摩尔吸光系数ε460=9.65×103;回归方程为:A=2.01×10-3.ρ 0.084;相关系数=0.999。方法具有操作简单、准确度高的优点。     

Separation of Phosphorus and Magnetic Mineral Fines from Siderite Reductive Ore by Applying Magnetic Flocculation

The characteristics of siderite reductive ore and the ultrafine grinding-magnetic flocculation separation (MFS) of this ore were investigated in the present work. The results indicated that the iron phase in the raw ore was predominantly metallic iron with an iron particle size below 30 μm, and the phosphorus compound was apatite. By applying MFS to siderite reductive ore containing 37.14% Fe and 0.52 P, a concentrate assaying 66.37% Fe and 0.19 P with 74.32% recovery was produced. The iron recovery increased by 5.77% compared with the results of the conventional magnetic separation. The high efficiency in phosphorus removal and iron recovery achieved by the MFS process may be attributed to the adequate liberation of iron particles and the increase in magnetic force on the iron mineral fines in the form of flocs in a magnetic field.     

提高重晶石还原率的方法

通过调整重晶石粒度、烧结温度、时间、进炉氧气量、回收尾气中的原料来提高重晶石的还原率。     

Reductive ethylation in ethereal solvents

Organic compounds, in particular anthracene and naphthalene, and two coals have been reductively ethylated in tetrahydrofuran (THF) and diglyme using alkali metals to form anions and ethyl iodide to produce ethylates. Product distributions were sensitive to experimental conditions. The rate of anion formation was controlled by their rate of desorption, probably as contact ion pairs, from the alkali metal surface. The enthalpy of formation of a solvated contact ion pair was ≈500 kJ mole^?1 mainly due to dipole-solvent interaction. 18-crown-6 ether was used to diagnose that, when treated with potassium in THF, anthracepe gave solvated contact ion pairs and probably di-anions whose reactions were characterized by the formation of ethyldihydroanthracene. Naphthalene under identical conditions gave loosely solvated mono-anions which reacted by electron transfer to give diethyldihydronaphthalene. With other alkali metals anthracene and naphthalene gave similar product distributions. The behaviour of other polynuclear aromatic hydrocarbons and of two coals was classified in the same way. It is suggested that when coals are readily solubilized by reductive alkylation mono-alkyldihydro products will predominate.     

新型环保防锈颜料磷钼酸铝锌中钼的测定

采用硫氰酸盐比色法测定新型环保防锈颜料磷钼酸铝锌中的钼,通过控制溶液的酸度和选择合适的还原剂,得到较好的实验结果:线性范围0～4.0μg· mL-1,相关系数R=0.9997,相对标准偏差RSD为3.60％～5.59％,回收率92.53％～105.20％,该方法的建立为防锈颜料中钼含量的测定提供了很好的方法.     

低品位钼矿制备钼酸铵的成品分析

本实验进行了低品位辉钼矿(8.37%)生产钼酸铵成品的纯度溶解试验、氯化物、硫化盐分析、及电感耦合离子体-质谱(ICP-MS)法对P、Ca、Fe、Na、Cu、Pb含量的测定。实验结果表明:钼酸铵成品最佳纯度为93.83%,钼总的回收率是83.55%。实验结果表明:此样品不溶于水,含有氯化物,不含有硫酸盐,Na=0.40 mg/g,Cu=8.57×10-3mg/g,Pb=0.81×10-3mg/g,不含有Ca、Mg。     

金属催化羰基化合物还原偶联反应的研究进展

羰基化合物还原偶联反应是形成碳一碳键最有效的方法之一,在有机合成中占有重要地位。羰基化合物还原偶联通常由羰基化合物与相应的金属试剂或金属络合物作用而实现,一般遵循单电子转移历程。本文综述了近年来金属钛、钐、铬等在羰基化合物还原偶联反应中应用的新进展。