三氯化钛还原-重铬酸钾滴定法测定铜冶炼烟尘中铁  

Determination of iron in copper smelting dust by titanium trichloride reduction-potassium dichromate titration method

作　　者：苗晓焕 MIAO Xiaohuan(BGRIMM MTC Technology Co.,Ltd.,Beijing 102628,China;Beijing Key Laboratory for Evaluation and Testing of Metallic Mineral Resources,Beijing 102628,China)

机构地区：[1]北矿检测技术股份有限公司,北京102628 [2]金属矿产资源评价与分析检测北京市重点实验室,北京102628

出　　处：《冶金分析》2024年第6期86-93,共8页Metallurgical Analysis

基　　金：国家重点研发计划(2021YFC2903101)。

摘　　要：铜冶炼烟尘基体复杂,在采用重铬酸钾滴定法测定铁含量时样品中高含量的铜、砷、锑、碳、硫、硅等元素会对测定产生干扰。实验采用氟化铵、盐酸、硝酸、硫酸、高氯酸溶解试样,用氢溴酸除去砷、锑的干扰,加入过量氨水生成氢氧化铁沉淀与铜、镍等分离,沉淀用盐酸溶解后,用氯化亚锡还原至溶液呈浅黄色,实现了重铬酸钾滴定法对铜冶炼烟尘中铁含量的测定。实验探讨了溶样方法、冒硫酸烟后保持的时间、砷或锑对测定的干扰、氯化铵用量、加入氨水后煮沸时间以及滤纸种类对测定结果的影响。优化后的条件如下:试样采用混合酸溶解后冒硫酸烟后保持15~30 min;当试样中砷含量大于1 mg或锑含量大于2 mg时需加入5 mL氢溴酸消除干扰;氯化铵用量为3~4 g;加入氨水后加热微沸1~2 min使沉淀完全;沉淀采用中速滤纸过滤。选取两个铜冶炼烟尘试样进行加标回收试验,加标回收率为99.00%~101.37%。按照实验方法测定4个铜冶炼烟尘试样,测定结果与电感耦合等离子体原子发射光谱法(ICP-AES)基本一致,相对标准偏差(RSD,n=11)为0.32%~0.56%。方法适用于铜冶炼过程中各个阶段烟尘中铁的测定,且不受试样基体差异性的影响。The matrix of copper smelting dust is complex,which contains high content elements such as copper,arsenic,antimony,carbon,sulfur and silicon,which could interfere with the determination of iron in sample by potassium dichromate titration.The sample was dissolved with ammonium fluoride,hydrochloric acid,nitric acid,sulfuric acid and perchloric acid.The interferences of arsenic and antimony were eliminated by hydrobromic acid.The excessive ammonia was added to form ferric hydroxide precipitate,realizing the separation from other elements such as copper and nickel.The precipitate was dissolved with hydrochloric acid,and the solution was reduced with stannous chloride to pale yellow.Thus,the determination of iron in copper smelting dust was realized by potassium dichromate titration method.The influence of some factors on the determination was discussed,including the method of sample dissolution,the duration of sulfuric acid smoke,and the interferences of arsenic or antimony,the dosage of ammonium chloride,the boiling time after adding ammonia and the type of filter paper.The optimized conditions are as follows:the duration of sulfuric acid smoke was 15-30 min after the sample was dissolved with mixed acid;When the content of arsenic in sample was higher than 1 mg or the content of antimony content was higher than 2 mg,5 mL of hydrobromic acid should be added to eliminate their interference.The dosage of ammonium chloride was 3-4 g.The boiling time after adding ammonia was 1-2 min for complete precipitation.The precipitates were filtered with medium speed filter paper.Two copper smelting dust samples were selected for recovery tests,and the recoveries were between 99.00% and 101.37%.Four copper smelting dust samples were determined according to the proposed method,and the results were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES).The relative standard deviations(RSD,n=11)were between 0.32% and 0.56%.The proposed method was applicable for the determination

关 键 词：铜冶炼烟尘 重铬酸钾滴定法 铁 砷 锑 

分 类 号：O655.2[理学—分析化学] TF801.3[理学—化学]