摘要
建立分光光度法测定锰矿石和锰精矿中铝含量。试样经盐酸和硝酸分解并用碳酸钠熔融处理残渣,在氯化锌和硼酸存在下,用强氢氧化钾溶液沉淀分离铁锰等,铝以铝酸盐的形式存在溶液中。定量分取10 mL试液,用盐酸和稀氢氧化钾溶液调整溶液pH值为1.5左右,加入聚乙烯醇作为稳定剂,在乙酸盐缓冲溶液(pH值为6~7)中,铝与铬天青S生成铬天青铝的络合物,在620 nm处以水作为参比溶液测定吸光度,以铝质量浓度和吸光度绘制标准曲线。测定11次空白溶液的吸光度,求得方法检出限为0.0039%(以称样量0.5 g计),以5倍检出限计算定量限为0.0195%。选取3个锰矿石成分分析标准物质GBW 07262、GBW 07265和58A Mn Ore 9-03,分别测定5次进行准确度和精密度验证,其平均值与认证值比较均能满足标准物质量值不确定度要求,相对标准偏差为1.76%~6.32%。所设计的试样分解方式、建立的校准曲线、分析条件的设置、称样量的选择和各种试剂的配比和用量能充分保证铝的释放和检测。
A spectrophotometry method for the determination of aluminum content in manganese ores and manganese concentrates was established.The samples were decomposed by hydrochloric acid and nitric acid and the residue was melted with sodium carbonate.In the presence of zinc chloride and boric acid,iron and manganese are separated by precipitation with strong potassium hydroxide solution.Aluminum existed in the solution in the form of aluminate.10 mL solution was transferred,the pH value was adjusted with hydrochloric acid and potassium hydroxide solution to about 1.5,and polyvinyl alcohol was added as stabilizer.In the acetate buffer solution(pH value was 6-7),aluminum and chromazure S formed a complex of chromium azurine-aluminum.The absorbance was determined with water reference at 620 nm.Plot a standard curve with aluminum concentration and absorbance.By measuring the absorbance of 11 blanks,the detection limit of the method was 0.0039%(calculated as the sample of 0.5 g),and the quantitation limit was 0.0195%(as 5 times of detection limit).Three manganese ore reference materials,GBW 07262,GBW 07265 and 58A Mn Ore 9-03 were determined for five times.Compared with the certified values,the average values could meet the uncertainties,and the relative standard deviation were 1.76%-6.32%.The method of sample decomposition,the calibration curve,the analysis conditions,the selection of test portion weight and the usage of various reagents could fully ensure the release and detection of aluminum.
作者
宋飞
丁仕兵
范玉
管嵩
冯丽丽
吴雅俊
李菲
SONG Fei;DING Shibing;FAN Yu;GUAN Song;FENG Lili;WU Yajun;LI Fei(Technology Center of Qingdao Customs,Qingdao 266500,China;Qingdao Bo Zheng Inspection Technology Co.,Ltd.,Qingdao 266500,China)
出处
《化学分析计量》
CAS
2024年第10期63-67,共5页
Chemical Analysis And Meterage
关键词
分光光度法
锰矿石
锰精矿
铝含量
铬天青S
spectrophotometry
manganese ores
manganese concentrates
aluminum content
chromazure S
