草酸盐法测定锰矿石中有效氧的误差分析

草酸盐法是测定锰矿石有效氧的常用方法之一，易产生系统误差。在分析产生误差的原因及影响因素的基础上，测定酸度、Mn^2 浓度、加热时间、光照时间、Fe^3 阻滞剂和隔绝空气等因素对草酸盐容量法测定有效氧的影响。实验结果表明：Mn^2 是其产生误差的主要因素。通过对比实验，改进后的草酸盐法优于经典草酸盐法，与亚铁法测定结果一致，能有效地减少因Mn^2 的催化作用而造成测定结果偏高的倾向。该实验方法的重现性好，测定结果准确。

ANALYSIS ON THE ERRORS IN THE DETERMINATION OF PYOLUSITE WITH OXALATE METHOD

The pyolusite in the manganese minerals was usually determined by the oxalate method,which would cause systematic errors.The reasons and influence factors for producing the error were analyzed in this paper.Experiments involving in theanalyses of acidity,the concentration of Mn~(2+),the heating time,the light time,the Fe~(3+) retardarce and the insolating air,were made to elucidate the influence on the determination of pyolusite.The results showed that Mn~(2+) was mainly responsible for the appearance of error.The oxalate method was proved to be better than the traditional oxalate method was in accordance to the recommended Ferro-method.This method can effectively restrict and decrease the upward tendency of the result duo to the catalysis of Mn~(2+),and therefore,was of good reproducibility and accuracy.