分光光度法分步测定高纯硅铁中铝钛磷

Determination of aluminum,titanium and phosphorus in high-purity ferrosilicon by spectrophotometry

快速准确测定高纯硅铁中铝、钛、磷含量,对于炉前产品判类入库,保证出厂产品质量以及指导冶炼工艺生产操作具有重要意义。试验采用硝酸和氢氟酸溶样,用高氯酸二次冒烟除硅和氟,有效控制第二次冒烟后剩余高氯酸量,以高氯酸为介质制成母液。分取同一母液采用铬天青S光度法测定铝,以Zn-EDTA掩蔽铁、锰、铜、镍等离子,甘露醇掩蔽钛离子,用六次甲基四胺-盐酸缓冲溶液控制pH值约为5.7时显色,取定量显色液用NH4F-EDTA溶液褪色为空白,测定高纯硅铁中0.010%~0.35%(质量分数,下同)的铝;采用变色酸光度法测定钛,用抗坏血酸消除铁(Ⅲ)等的干扰,使用乙酸铵控制pH值约为3,取定量显色液用NH4F-EDTA溶液褪色为空白,测定高纯硅铁中0.010%~0.30%的钛;采用国家标准GB/T4333.2—1988《硅铁化学分析方法铋磷钼蓝光度法测定磷量》测定高纯硅铁中0.008%~0.060%的磷量。方法中各元素的检出限为0.00049%~0.0023%。按照实验方法对3个硅铁标准样品中铝、钛、磷进行分析,测定值与标准值的结果相一致,相对标准偏差(RSD,n=6)为0.022%~0.073%。

The rapid and accurate determination of aluminum,titanium and phosphorus in high-purity ferrosilicon has important significance for the classification and warehousing of matter products to guarantee the quality of outgoing products and guide the smelting process and operation.Sample was dissolved with nitric acid and hydrofluoric acid.The silicon and fluorine were removed by secondary fuming of perchloric acid.The residual amount of perchloric acid after secondary fuming was effectively controlled.The mother solution was prepared in the medium of perchloric acid.The content of aluminum in mother solution was determined by chromazurine S spectrophotometry.The ions such as iron,manganese,copper and nickel were masked with Zn-EDTA.The titanium ions were masked with mannitol.The pH was controlled at about 5.7 with hexamethylenetetramine-hydrochloric acid buffer solution for coloring.The coloring solution with certain volume was treated with NH 4F-EDTA solution for fading and used as blank.Then the content of aluminum(0.01%-0.35%,mass fraction)in high-purity ferrosilicon was determined.The content of titanium was determined by chromotropic acid spectrophotometry.The interference of iron(Ⅲ)was eliminated with ascorbic acid.The pH was controlled at about 3 with ammonium acetate.The coloring solution with certain volume was treated with NH 4F-EDTA solution for fading and used as blank.Then the content of titanium(0.010%-0.30%)in high-purity ferrosilicon was determined.The content of phosphorus(0.008%-0.060%)in high-purity ferrosilicon was determined according to national standard GB/T 4333.2-1988 Methods for chemical analysis of ferrosilicon-The reduced molybdobismuthylphosphoric acid photometric method for the determination of phosphorus content.The detection limits of elements were in range of 0.000 49%-0.002 3%.The content of aluminum,titanium and phosphorus in three standard samples of ferrosilicon was analyzed according to the experimental method,and the found results were consistent with the certified values.The relative standard deviations(RSD,n=6)were between 0.022%and 0.073%.