由于氯离子的存在会对不锈钢产生危害,因此及时准确地测定加入到不锈钢焊条药皮中的脱硫剂镁粉中的氯离子含量非常必要.试样经硝酸溶解,加入酚酞指示剂,用氢氧化钠溶液调节pH值至6～8,定容至100 mL后将溶液转移至150 mL烧杯内,加入2 mL硝酸钠溶液,搅拌均匀后直接采用离子选择电极测定镁粉中氯离子含量.实验表明,氯离子质量浓度在0.01～100mg/L范围内与其电位值呈良好的线性关系,检出限为0.005 mg/L.实验方法用于生产用镁粉样品中氯离子含量的测定,相对标准偏差(RSD,n=9)为1.2％;按照实验方法对镁粉样品进行加标回收,回收率在94％～104％之间.与国家轻金属质量监督检测中心采用国家标准方法检测进行对比,测定结果基本一致.%The presence of chlorine ion will cause harm to the stainless steel,so it is quite necessary to timely and accurately determine the chlorine ion content added into desulfurizer magnesium powder in electrode covering of stainless steel.The sample was dissolved in nitric acid.After adding phenolphthalein indicator,the pH was adjusted to 6-8 with sodium hydroxide solution.The solution was then diluted to 100 mL and transferred into 150 mL beaker.After adding 2 mL of sodium nitrate solution and uniformly mixing,the content of chlorine ion in magnesium powder was directly determined by ion selective electrode method.The experimental results showed that the mass concentration of chlorine ion in range of 0.01-100 mg/L had good linear relationship to the corresponding potential value.The detection limit was 0.005 mg/L.The proposed method was applied for the determination of chlorine ion content in magnesium powder sample.The relative standard deviation (RSD,n=9) was 1.2％.The recovery tests of magnesium powder sample were conducted according to the experimental method.The recoveries were between 94％ and 104％.The found results were consistent with those obtained by standard method in National Light Metal Quality Supervision and Inspection Center.
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