硅钼蓝分光光度法测定铝钛硼合金中硅  

Determination of silicon in aluminum-titanium-boron alloy by silicon molybdenum blue spectrophotometry

作　　者：唐清 黄葡英 李雨 TANG Qing;HUANG Puying;LI Yu(Center for Industrial Analysis and Testing,Guangdong Academy of Sciences,Guangzhou 510650,China)

机构地区：[1]广东省科学院工业分析检测中心,广东广州510650

出　　处：《冶金分析》2022年第5期43-47,共5页Metallurgical Analysis

基　　金：国家自然科学基金青年基金项目(52001074);2021年广东省省属科研机构改革创新领域稳定支持项目;广州市科技计划项目(202102020626);广东省科学院建设国内一流研究机构行动专项资金项目(2021GDASYL20210103086)。

摘　　要：在采用硅钼蓝分光光度法对铝钛硼合金中硅进行测定时,样品中的钛会与钼酸铵反应生成钼酸钛沉淀,使溶液中钼酸根浓度降低,影响硅钼酸发色,同时钼酸钛沉淀也会因散射作用使吸光度发生变化,从而对测定结果产生影响。实验采用氢氧化钠和过氧化氢溶解样品,于微酸性条件下,在硅钼黄显色阶段加入两倍于普通硅钼蓝分光光度法中钼酸铵的量,可以实现硅钼黄显色完全。在将硅钼黄还原为硅钼蓝前,加入草酸-硫酸混合酸,因草酸对钛有络合作用,能加速钼酸钛的溶解,故而消除了钼酸钛沉淀对测定的干扰。用抗坏血酸还原硅钼黄为硅钼蓝,稳定30 min后,于分光光度计上在波长660 nm处进行测定,建立了不分离钛直接用分光光度法测定铝钛硼合金中硅的方法。结果表明,在优化的实验条件下,硅质量在50~250μg范围内与其对应的吸光度呈现良好的线性关系,相关系数不小于0.999。检出限为0.002 8%(质量分数),定量限为0.009 3%(质量分数)。共存离子的干扰试验表明,铝钛硼合金中钛、硼、铝、铁、钒在其含量上限时,不干扰硅的测定。将实验方法用于测定铝钛硼合金样品中硅,结果与电感耦合等离子体原子发射光谱法(ICP-AES)或重量法测定结果吻合,相对标准偏差(RSD,n=11)小于1%。During the determination of silicon in aluminum-titanium-boron alloy by silicon molybdenum blue spectrophotometry,titanium in sample can reaction with ammonium molybdate to form titanium molybdate precipitation,which reduces the concentration of molybdate in solution and have an influence on the coloring of silicomolybdic acid.Meanwhile,the titanium molybdate precipitation can also change the absorbance due to the scattering effect,thus affecting the determination results.The sample was decomposed by sodium hydroxide and hydrogen peroxide in experiments.Under slightly acidic conditions,the addition of ammonium molybdate in the coloring stage of silicon molybdenum yellow with two-fold dosage of that in traditional silicon molybdenum blue spectrophotometry could realize the complete coloring of silicon molybdenum yellow.Before reducing silicon molybdenum yellow to silicon molybdenum blue,the mixture of oxalic acid and sulfuric acid were added to accelerate the dissolution of titanium molybdate due to the complexation between oxalic acid and titanium,thus eliminating the interference of titanium molybdate precipitation with the determination.The ascorbic acid was used to reduce silicon molybdenum yellow to silicon molybdenum blue.After stable for 30 min,the absorbance of solution was measured on spectrophotometer at wavelength of 660 nm.The method for direct determination of silicon in aluminum-titanium-boron alloy by spectrophotometry without separation of titanium was established.The result showed that the mass concentration of silicon in range of 50-250 μg had a good linear relationship with the corresponding absorbance under the optimized experimental conditions.The correlation coefficient was not less than 0.999.The limit of detection and limit of quantification was 0.002 8%(mass fraction) and 0.009 3%(mass fraction),respectively.The interference test of coexisting ions showed that when the contents of titanium,boron,aluminum,iron and vanadium in aluminum-titanium-boron alloy was at the upper limit,these eleme

关 键 词：硅钼蓝分光光度法 铝钛硼合金 硅 钛 

分 类 号：O657.32[理学—分析化学] TF125.22[理学—化学]