高温硝解EDTA容量法快速测定铅精粉中的铅

试样经NH4HF2助溶,HNO3-KClO3溶解后,在冒SO3白烟时（340℃）,高温硝解残渣。在1mol/L的H2SO4介质中沉淀铅,生成PbSO4沉淀,过滤除去溶解于溶液的干扰元素,用pH=5.5～5.9的HAC-NAC缓冲溶液溶解PbSO4沉淀,以二甲酚橙作指示剂,EDTA容量法测定铅。本方法克服了国标方法测定流程长,多点测定（残渣、滤液、溶液中的铅）,溶解矿样过程繁杂,费时费力等缺点。建立的方法可一次性测定铅量,经用铅精粉国家一级标准物质GBW07167验证,结果与标准值吻合,方法的精密度RSD%（n=11）在0.1%～0.3%之间,方法简便、快速。适合于钡含量低（〈2%）的铅精粉中铅的测定。

Determination of Lead Content in Lead Powder by High Temperature Nitrolysis Edta Volumetric Method

The samples are dissolved in HNO3-KClO3 solution assistant by NH4HF2,and then the black slag is processed by high temperature nitrolysis when white smoke of SO3 is released（when the temperature is 340℃）.The dissolved lead is deposited by adding of 1 mol/L H2SO4 solution in form of PbSO4,where the interfering element can be removal by filtrate.The PbSO4 powder is dissolved in HAC-NAC buffer solution（pH=5.5～5.9）,while the Pb content can be quick measured by EDTA volumetric method with the indicator of xylenol orange.The degree of precision of high temperature nitrolysis EDTA volumetric is tested by national primary standard material of GBW07167 to reach the RSD% of 0.1%～0.3%（n=12）.This new method are more simple and quicker than national standard method,because the latter is contain the longer and complex sample dissolution process,and the more complex Pb content measure process which need measure the draff,filtrate,and solution at the same time.For barium content is low（ 2%） of the determination of lead content in lead powder.