间接光度法测定水中硫酸根

硫酸根离子的测定是水质分析主要项目之一。常见分析方法包括硫酸钡比浊法和铬酸钡光度法。但前者不稳定,分析条件较为严格,分析结果重现性和准确度不理想;而后者铬酸钡悬浊液配制麻烦,硫酸盐与铬酸钡交换反应缓慢,过滤除去硫酸钡和过量铬酸钡也费时。也有用二甲基磺基偶氮肿Ⅲ光度法,但必须采用阳离子交换树脂消除某些阳离子的干扰。本文利用氯化钡和铬酸钾等摩尔反应生成铬酸钡,加入等摩尔氯化钡和铬酸钾以代替铬酸钡悬浊液,溶液中存在的铬酸根与溴邻苯三酚红反应生成黄色产物,溴邻苯三酚红与反应产物的对比度达90nm,建立了测定硫酸根较为快速且结果可靠的方法。     

硅钡合金中钡的测定

硅钡合金是球铁生产中常用的高效长效孕育剂和炼钢强脱氧剂 ,其钡的质量分数为 0 .6%～ 40 % ,硅的质量分数为 40 %～ 70 %。报道过的测定钡的分析方法很多[1,2 ] ,通常采用硫酸钡重量法测定或以硫酸钡沉淀的形式与干扰元素分离 ,继续以 EDTA配合滴定法测定钡。试验了在乙酸 -乙酸钠缓冲溶液中 ,以氨三乙酸为掩蔽剂与铁生成稳定的 NTA- Fe配合物 ,铬酸铵沉淀钡为铬酸钡 ,与共存的干扰元素分离。用稀盐酸溶解铬酸钡沉淀 ,以硫酸亚铁铵标准溶液滴定铬酸根 ,间接求出钡的含量。方法重现性较好 ,回收率大于 99% ,相对标准偏差为 0 .2 7%。1…     

火焰发射法测定铝硅钡铁中高含量钡

铝硅钡铁是新型的脱氧剂之一,由于价格较便宜,使用效果好而广泛应用于炼钢工艺中.有关钡的分析方法通常采用硫酸钡沉淀重量法或铬酸钡容量法,但分析步骤冗长,费工费时.氧化亚氮-乙炔火焰原子吸收法比较合适,但未能普及.此外,曾有火焰发射法测定玻璃中氧化钡的报道,此方法主体硅被除去,其它引起干扰的金属元素含量甚少.本文建立了用空气-乙炔火焰原子发射法,样品不经分离直接测定钡的灵敏而简便快速的分析方法;研究了基体的影响及消除方法.试验结果表明,本方法简便、快速、精密度和准确度均好,能满足生产的要求.1 试验部分1.1 仪器与试剂日立180-80型塞曼偏振原子吸收分光光度计     

硫酸沉淀分离-电感耦合等离子体质谱法测定钡矿石中微量锌

建立电感耦合等离子体质谱(ICP–MS)仪测定钡矿石中锌的方法。研究了Ba++对66Zn的干扰及干扰消除方法。在酸性介质中,硫酸与钡离子形成稳定的硫酸钡沉淀,通过过滤分离沉淀,锌保留在溶液中。在碰撞池模式下,利用铑(Rh)作为内标校正仪器漂移和基体效应,用ICP–MS法测定过滤后的溶液。锌的质量浓度在0.1～200μg/L范围内具有良好的线性关系,线性相关系数为0.999 9,方法检出限为6.9μg/g。测定结果的相对标准偏差均小于5%(n=5)。用该方法测定国家标准物质,测定值与推荐值相符。该法操作简便,测定结果可靠,适于钡矿石中微量锌的测定。     

应用氨三乙酸络合大量铁测定矿石中钡

铬酸钡容量法测定钡是经典方法,由于该法行之有效,仍在日常生产分析中使用。但对铁矿石中钡的测定,因存在大量铁,于pH5.7～6.1沉淀铬酸钡时发生水解,使测定结果偏高。曾有人用柠檬酸掩蔽铁以消除干扰。经试验表明,由于柠檬酸的缓冲作用,溶液的沉淀酸度不易调节,掩蔽铁的效果也不理想。本文采用氨三乙酸(NTA)掩蔽铁(Ⅲ)效果较好,1克NTA可掩蔽100毫克铁(Ⅲ),並可借助铁-氨三乙酸络合物,在不同pH下显不同颜色,来指示和调节溶液的沉淀酸度。方法简便,可用于铁矿石中含量在0.x～xx%钡的测定。分析步骤称取0.1000～0.5000克试样于刚玉坩     

氧化亚氮-乙炔火焰原子吸收法测定矿石中的钡

钡在空气-乙炔火焰中因受到多种因素干扰,直接测定钡难以得到正确结果並且灵敏度低,但在氧化亚氮-乙炔火焰中却有较高灵敏度且几乎消除了干扰。本文着重对氧化亚氮-乙炔火焰原子吸收法测定钡时的最佳原子化区的选择、共存元素的干扰、电离干扰、分子光谱干扰等进行了研究。方法简便、快速,准确度与精密度令人满意。一、主要仪器与试剂日立508型原子吸收分光光度计;氧化亚氮(钢瓶装)。钡标准溶液称取1.437克经110℃烘干的光谱纯碳酸钡,溶於20毫升硝酸(1+1)中,移入1升容量瓶并定容。此溶液为1毫克钡/毫升。钾盐溶液将5.18克硝酸钾(分析纯)溶於100     

测定重晶石中硫酸钡时分离铅的研究

本文提出了用乙酸-溴水冷浸和2％乙酸铵热洗涤分离重晶石中的方铅矿(PbS)和它的次生氧化物硫酸铅以及毒重石(BaCO_3)的方法。本法不仅能定量分离铅和碳酸钡,而且使硫酸钡在分离中的损失由原来的2—3％减少至1％以下,从而提高了方法的准确度,操作简便易行。试验表明,冷浸热洗涤分离铅时硫酸钡损失的绝对量只有2毫克左右;在pH为5.7—6.1的乙酸-乙酸钠介质中用重铬酸铵分离锶时硫酸钡损失的绝对量为1毫克左右。     

原子吸收光谱法间接测定生活饮用水中硫酸盐

硫酸盐在自然界中广泛存在，一般地下水及地面水均含有硫酸盐。硫酸盐是生活饮用水水质常规检验项目之一。《生活饮用水卫生规范》中测试方法有硫酸钡灼烧称量法、铬酸钡比色法、硫酸钡比浊法及离子色谱法，且操作繁杂，条件控制要求严格。本文以火焰原子吸收光谱法测定中间钡离子而间接测定水中硫酸盐，具有操作简单、准确度好、精密度高，能满足生活饮用水中硫酸盐的测定要求。     

原子吸收分光光度法测定钡冕光学玻璃中的氧化钙

玻璃中氧化钙的测定,通常采用EDTA络合滴定法,由于终点不灵敏,误差较大。当玻璃中存在大量氧化钡时,为了消除钡的干扰,需以硫酸盐的形式进行过滤分离,手续繁琐冗长。本工作拟定一个原子吸收测定高钡光学玻璃中氧化钙的简易方法,选用镧作释放剂消除铝的干扰,在标准溶液中加入与分析溶液相同浓度的钡控制钡的影响。分析过程简单、快速、准确度高。并适用一般光学玻璃中氧化钙的测定。干扰情况:钡冕光学玻璃组成复杂,在用原子吸收测定钙时,不仅铝的干扰十分严重,而且同族钡离子的电离干扰也是不可忽视的,特别是     

碳酸钡单晶微米锥阵列在方解石(104)面上的外延生长

通过液固界面上的溶解-沉淀耦合反应在Ba(NO₃)₂乙醇-水溶液中实现了毒重石晶型的碳酸钡在方解石(CaCO₃)晶体基底上的外延生长, 得到碳酸钡的单晶微米锥阵列. 碳酸钡微米锥的长轴平行于毒重石晶体的[001]方向,同时也与方解石基底[001]晶向相同, 其俯视图为六边形, 具有近似的六方对称性. 随反应时间的增加, 外延生长形成的碳酸钡微米锥的尺寸增加, 但其轴径比逐渐减小. 通过改变乙醇-水混合溶剂中的乙醇含量或者Ba(NO₃)₂浓度也能调控碳酸钡晶体的尺寸和形貌. 随着混合溶剂中乙醇含量与Ba(NO₃)₂浓度的提高, 溶液中BaCO₃的过饱和度增加, 通过外延生长在方解石的(104)表面形成的BaCO₃阵列结构的密集程度逐渐增加, 尺寸逐渐减小, 形貌从微米锥逐渐转变为微米柱状结构. 经过对晶化过程及毒重石和方解石晶体结构分析,提出了在方解石表面外延生长形成的毒重石微米锥单晶阵列结构的形成过程机理: 该过程为界面溶解-沉淀耦合反应的过程,方解石的溶解和毒重石的外延生长过程同时进行, 由于两种晶体在方解石基底的(104)晶面与(001)晶面上具有中高度错配值, 毒重石晶体在方解石的这两个晶面上发生Volmer-Weber型的外延生长, 逐渐形成在靠近基底处包覆有方解石台阶的毒重石微米锥单晶阵列结构.     

分光光度法测定三氧化铀中的硫酸根

采用TBP-萃淋树脂吸附三氧化铀样品中的铀,硫酸根与铬酸钡进行交换反应后,直接比色法测定硫酸根的含量。实验中研究了三氧化铀样品中硫酸根含量测定的样品制备、分离、反应酸度,煮沸时间,铬酸钡用量等影响因素。优化条件下,采用硝酸(5mol/L)淋洗、1mL HCl溶液(2.5mol/L)调节溶液中酸浓度、使用2mL BaCrO_4进行交换反应、煮沸3min,得到方法相对标准偏差小于10%,加标回收率为92.9%～110%。实验结果表明,直接显色的测定方法灵敏、快速、准确度高。方法测定条件易于获得,适于推广应用。     

The kinetics of the crystallization of barium chromate in presence of polyphosphate and phosphonates

Summary The inhibiting effect of polyphosphate and phosphonates on the crystallization of barium chromate for both seeded and unseeded systems has been investigated using the changes in ionic conductivity of the lattice ions in supersaturated solutions containing stoichiometric concentrations of barium and chromate at 298 K. The inhibitors studied are sodium tripolyphosphate (STP), ethylenediaminetetramethylenephosphonic acid (ENTMP), and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). The effect of these inhibitors on the growth of crystals has been studied at several inhibitor concentrations. The influence of these additives on barium chromate crystallization could be interpreted in terms of aLangmuir type adsorption isotherm. The crystallization retarding effect due to inhibitors is in the orderHEDP>STP>ENTMP. The inhibitors studied can be used as effective compounds for scale formation control.Deceased     

Indirect Determination of Sulfate by Atomic Absorption Spectrophotometry

With a flow injection technique, the content of sulfate in solution was determined indirectly from the concentration of partially equilibrated barium ion in solution. To obtain improved sensitivity, atomic absorption spectrophotometry of a flame was used to determine barium. With these procedures combined with a linear calibration graph, superior sensitivity and detection limit of sulfate determination were obtained compared with those from other indirect methods.     

天然水中硫酸根的交流示波极谱滴定

在NH_4Ac溶液中加入标准Ba~(2+)溶液沉淀SO_4~(2-)用标准K_2CrO_4溶液滴定过量Ba~(2+)。过量的CrO_4~(2-)在交流示波极谱图上出现切口指示终点,间接求出天然水中SO_4~(2-)含量。     

人工活性膜模板制备铅钡铬酸盐纳米棒及其光学性能

利用胶棉人工活性膜模板与乙二胺的协同作用，成功制备了铬酸铅、铬酸钡纳米棒.前者直径范围为28～55 nm，最大长径比为25，结构为单斜单晶；后者直径范围为24～38 nm，最大长径比为28，结构为正交单晶.产物相对于其体材料而言，红外光谱峰值仅有少量蓝移，而紫外-可见光谱最大吸收峰则分别蓝移了30 nm和35 nm，荧光发射峰也分别蓝移了9 nm和15 nm，这均是纳米材料量子尺寸效应的体现.还对产物的形成机理作了初步探讨.     

The flame photometric determination of calcium in phosphate,carbonate, and silicate rocks

A flame photometric method of determining calcium in phosphate, carbonate, and silicate locks has been developed Aluminum and phosphate interference was overcome by the addition of a large excess of magnesium. The method is rapid and suitable for routine analysis Results obtained are within ± 2% of the calcium oxide content.     

Analytische auswertung von austauschreaktionen zwischen löslichen und wenig löslichen elektrolyten

After an explanation of the theoretical basis of exchange reactions between soluble and difficultly soluble electrolytes, their advantages and disadvantages as analytical test reactions were illustrated by the following examples: 1. identification of oxalatc and fluoride by their reaction with calcium carbonate; 2. identification of sulfate and chromatc with barium carbonate; 3. identification of phosphate and chromate with lead carbonate; 4. identification of the halogens with silver carbonate; 5. identification of bromide and iodide with .silver thiocyanatc; 6. identification of bromide with silver thiocyanatc and photodecomposition; 7. identification of phosphate and oxalate with lead iodate; 8. identification of the halogens with silver iodate.The mechanism of these reactions is discussed and a hypothesis formulated to explain why ion exchange ensues, even if the concentration of the reagents is smaller than would be necessary for mass precipitation. Many of the reactions described arc not listed in jacouson's Encyclopedia of Chemical Reactions.     

Solubility and solubility constant of barium sulfate in aqueous sodium sulfate solutions between 0 and 80°C

The solubilities of barium sulfate in aqueous solutions of sodium sulfate were studied at ionic strengths from 0.0005 to 0.02 mol-kg^–1 and at 0, 20, 40, 60, and 80°C. The solubility data were used to calculate the solubility constants using an extrapolation method. The solubility constant obtained were in good agreement with literature data. The mean activity coefficients of barium sulfate in aqueous solutions of sodium sulfate were also studied.     

Precipitation of barium chromate from homogeneous solution using complexation and replacement A separation of barium from relatively large amounts of strontium and lead

A new procedure is presented that efficiently separates barium from relatively large amounts of strontium and lead. The barium is precipitated as the chromate from a solution in which the multivalent cations are complexed with EDTA. The barium ions are homogeneously released in solution when magnesium ions are slowly introduced into the solution. The magnesium ions gradually replace the barium ions from their EDTA complexes, bringing about a precipitation of barium chromate from homogeneous solution.

This slow formation of barium chromate crystals holds co-precipitation to a minimum and produces crystals that are easily filtered and washed. More than 99.7% of the barium can be precipitated as the chromate, with less than 0.6% of the strontium, when the two ions are in equal molar concentration.     

原位诱导生长法制备单分散M型钡铁氧体亚微空心球

提出了一种制备单分散M型钡铁氧体空心球的新方法,即以碳酸胍表面改性的单分散聚(苯乙烯-共-丙烯酸)P(St-co-AA)乳胶粒子为模板,在其表面原位诱导钡铁氧体前驱物的定位并生长,以此获得壳层均匀致密的P(St-co-AA)/钡铁氧体前驱物核壳复合粒子,再经过热处理得到结构完整、成分单一的M型钡铁氧体空心球.