镀铬溶液中铝的测定

１方法摘要在ｐＨ＝５．４的溶液中,加过量的ＥＤＴＡ并加热,使与铝完全络合,然后用标准锌溶液滴定过量的ＥＤＴＡ,加入氟化铵固体,使与铝络合所相当的ＥＤ－ＴＡ被释出,用标准锌溶液滴定之。２试剂１．六次甲基四胺缓冲液（ｐＨ＝５．４）配制：称４０ｇ六次甲基四...     

络合滴定法对EDTA和NTA混合体系中二者含量的分别测定

建立了ＥＤＴＡ、ＮＴＡ、混合体系中二者含量的络含滴定检验法。在ＰＨ＝３．５时,以钛铁试剂为指示剂,用铁离子滴定ＥＤＴＡ和ＮＴＡ的总和,在ＰＨ＝６时,用铁离子滴定ＥＤＴＡ的含量,二次滴定差值即为ＮＴＡ的含量。该方法快速简便,准确度高,是对ＧＢ１４１０的补充和完善,尤其适用于生产的现场控制分析。     

饲料级磷酸氢钙中钙的分析方法探讨

饲料级磷酸氢钙中钙含量的测定采用配位滴定法,按ＨＧ２６３６－９４标准进行：在试样中加入过量的ＥＤＴＡ与钙配位,加缓冲溶液（ｐＨ＝１０）１０ｍｌ,以Ｋ．Ｂ为指示剂,用锌标准溶液滴定过量的ＥＤＴＡ,以空白试验与试样溶液消耗锌标准溶液的体积差为钙消耗ＥＤＴ...     

选择性螯合滴定法测定铋

用ＭＳＡ为释放剂，选择性螯合滴定法测定镀层和镀液中铋。用ＥＤＴＡ螯合Ｂｉ＾３＋和其他阳离子，然后加入ＭＳＡ分解Ｂｉ－ＥＤＴＡ螯合物，释放出的ＥＤＴＡ用锌标准溶液返滴定。实验结果表明，各种阳离子都不干扰。该方法已成功地用于测定锡铋铈合金镀层和镀液中的含量。     

涂料用稀土催干剂中稀土金属含量分析研究

在一定条件下，以ＥＤＴＡ为络合剂，以二甲酚橙为指示剂，用络合滴定法测定了涂料用稀土催干剂中稀土金属的含量。     

涂料用稀土催干剂中稀土金属含量分析研究

在一定条件下，以ＥＤＴＡ为络合剂，以二甲酚橙为指示剂，用络合滴定法测定了涂料用稀土催干剂中稀土金属的含量。     

分光光度法快速测定硅酸盐中镁的含量

目前水泥厂硅酸盐试样中镁的测定常采用ＥＤＴＡ滴定法,即在ｐＨ＝１０时用ＥＤＴＡ滴定钙、镁的合量,在ｐＨ＞１２时用ＥＤＴＡ滴定钙离子,然后用差减法求出镁的含量。该方法准确度低,操作麻烦。利用光度法测定镁时由于钙、镁性质相似,硅酸盐试样中大量存在的钙严重...     

3,5-diBr-PADAP作为铁和铜配位滴定指示剂的研究

研究了３,５ｄｉＢｒＰＡＤＡＰ作配位滴定的指示剂,在ｐＨ１．８～２．０时用ＥＤＴＡ标准溶液滴定铁（Ⅲ）;在滴定铁（Ⅲ）后的溶液中,加入对Ａｌ３＋过量的ＥＤＴＡ标准溶液,在ｐＨ３．８～４．０时与Ａｌ３＋生成稳定的络合物,调至ｐＨ５．０,用氟化铵置换出Ａｌ－ＥＤＴＡ配合物中的ＥＤＴＡ,用硫酸铜标准溶液滴定,测定铝     

选择性螯合滴定法测定镍含量

选择性螯合滴定法测定镍是采用过量ＥＤＴＡ螯合镍离子及其它金属离子，然后用ＳＣＮ＾－，Ｃ５Ｈ５Ｎ选择分解Ｎｉ－ＥＤＴＡ，释放出ＥＤＴＡ，用Ｐｂ（ＮＯ３）２标准溶液滴定，从而计算镍的含量。以ＸＯ－ＭＴＢ－ＣＰＢ为混合指示剂，终点变化敏锐。本法操作简便，结果准确，可用于测定电镀液和镍基合金镀层中的镍。     

用TGA作释放剂选择性螯合滴定法测定锡

叙述了选择性螯合滴定法测定锡。在含有锡（Ⅳ）和其它阳离子的溶液中，加入过量ＥＤＴＡ，在ｐＨ５～６，以ＸＯ－ＣＰＢ为混合指示剂，用Ｐｂ（ＮＯ３）２标准溶液返滴过量的ＥＤＴＡ。然后加巯基乙酸（ＴＧＡ）分解Ｓｎ（Ⅳ）－ＥＤＴＡ螯合物，释放出的ＥＤＴＡ，用Ｐｂ（ＮＯ３）２返滴定。研究了各种阳、阴离子的干扰。此法用于测定镀铅锡合金溶液、无氰铅基合金镀层中锡的含量。     

锌精粉中锌、铁含量的连续测定

以硝酸-氯酸钾体系分解样品,以二甲酚橙作指示剂,用EDTA标准溶液作滴定剂测定锌精粉中锌含量;沉淀用盐酸分解,以二苯胺磺酸钠作指示剂,用重铬酸钾标准溶液作滴定剂测定锌精粉中铁含量,实现锌精粉样品中锌、铁含量的连续测定,且RSD均小于3%,试验测定值与标准推荐值相吻合,能满足日常生产要求.     

硫酸铵-氨水溶样测定氧化锌含量

研究采用硫酸铵-氨水溶解氧化锌试样,EDTA滴定法测定氧化锌含量.结果表明,用200 g·L<'-1>硫酸铵溶液10 mL,5 mL氨水溶解分析试样,搅拌5 min后试样中氧化锌溶解完全,金属锌、氧化铁等杂质不溶,氧化锌的测定不受这些杂质的干扰,测定结果与传统溶样方法的测定结果相吻合,相对标准偏差小于0.1%.     

Rare-earth silicates

Binary systems of the type Ln₂O₃SiO₂ were studied. Three types of compounds were established for them: Ln₂O, SiO₄ (1:1) diorthosilicate, Ln₂Si₂O₇ (1:2), and the apatite-like silicate, Ln_4.67O [SiO₄]₃ (7:9), the latter being stable for the large cations. Systematization of the physical-chemical properties of rare-earth silicates was made. Based on the model of ideal solutions the liquidus curves were calculated for several Ln₂O₃  Ln₂O₃SiO₂ systems. The solid solution limits were determined for complex systems formed by rare-earth and alkaline-earth silicates. A series of rare-earth single crystals of simple and complex composition were grown by crystallization from molten solutions. Classification of the same type compounds into structural groups (morphotropic series) was made and partecipation of the 4f-orbitals in bondings was considered. The spectral-luminiscence characteristics of the rare-earth silicates are given.     

酸性锌镍合金镀液中镍、锌和硼酸的分析方法

制定了酸性锌镍合金镀液中镍、锌和硼酸的分析方法。用EDTA光度法测定镍;用EDTA容量法测定锌和镍的总量,用差减法计算锌的质量浓度;用甘露醇与硼酸反应生成酸性较强的络合酸,用亚铁氰化钾掩蔽锌和镍离子,以酚酞作指示剂用氢氧化钠滴定硼酸。这三种方法的准确度都较高,能够满足镀液中锌、镍和硼酸的监控要求。     

酸性镀铜溶液中硫酸铜和锌杂质的分析方法

酸性镀铜溶液中的锌杂质严重影响硫酸铜的测定结果。介绍了硫酸铜和锌杂质的分析方法。用三乙醇胺光度法测定硫酸铜,用EDTA容量法测定硫酸铜和锌杂质的总量,从总量中减去硫酸铜的量得到锌杂质的质量浓度。方法简单,快速而准确,能够满足监控酸性镀铜溶液的要求。     

Amino Acids as Retaining Agents in Displacement Chromatography of the Rare-Earth Elements

Abstract

The feasibility of using amino acids as retaining agents with ethylene-diaminetetraacetic acid (EDTA) eluents in displacement chromatography of the rare-earth elements was studied at 85° to 90°C. Hydroxyethyl-ethylenediaminetriacetic acid (HEDTA) and diethylenetriaminepeuta-acetic acid (DTPA) were the most effective retaining agents investigated. Elements of atomic numbers 39 and 57 through 68 were effectively retained, whereas elements of atomic numbers 69 through 71 passed through the retaining-agent band. Utilization of HEDTA or DTPA as retaining agents permits the use of 7 to 10 g/liter EDTA eluting solutions, whereas eluting solution concentrations in the 4–4,5 g/liter range are maximum when using hydrogen or copper as retaining agents. Eighty-five per cent recovery of the EDTA eluent collected before rare-earth breakthrough and during elution of lutetium, ytterbium, and thulium, and essentially complete recovery of the HEDTA or DTPA retaining agents, are possible without extensive processing.     

缩二脲锌配合物的合成与表征

以硝酸锌、乙酸锌及硫酸锌和缩二脲为原料,在甲醇溶液中反应合成了3种含有不同阴离子和结晶水的缩二脲锌配合物[Zn(bi)2](NO3)2·2H2O、[Zn(bi)2](Ac)2·1.5H2O和[Zn(bi)2]SO4·0.25H2O(bi=NH2CONHCONH2),用EDTA配位滴定、元素分析、X射线粉末衍射、红外光谱对产物进行组成和结构表征,并研究了配合物的热分解过程。实验结果表明,锌离子与缩二脲中的羰基氧原子配位,形成了配位数为4的配合物。配合物的热分解过程包括失水、配体及阴离子的氧化分解过程,最后完全分解形成氧化锌。     

EDTA容量法测定氧化锌锡粉末材料中的锌

采用 EDTA容量法测定氧化锌锡粉末中的锌含量.以酒石酸为掩蔽剂掩蔽锡,用氨水调节pH值并加入六亚甲基四胺-HCl缓冲溶液,将pH值控制在 5.10,以二甲酚橙为指示剂直接滴定锌.锌的回收率在97.6%～100.5%之间,标准偏差和相对标准偏差都符合分析要求.     

Liquid-Liquid Extraction of Zinc with Aliquat 336-S-Br from Aqueous Bromide Solutions

Abstract

A new solvent extraction system has been developed for zinc in aqueous bromide solution using Aliquat 336-S-Br-xylene solution as an extractant. A 1 mg/ml zinc solution is extracted essentially quantitatively with an equal volume of 5% Aliquat 336-S-Br-xylene solution in 15 sec. The extracted zinc can be stripped from the nonaqueous layer with a series of aqueous solutions including Na₂SO₃ (≥m 1.0 M) NaOH (≥m 0.5 M), NH₃ (≥m 0.5 M), ethylenediamine (≥m 0.3%), and EDTA (≥m0.5%). The extraction is quantitative only from acidic solutions. High aqueous to organic phase ratios can be utilized without loss of extraction efficiency.