电感耦合等离子体发射光谱法测定石灰岩中游离二氧化硅

Determination of free silica in limestone by inductively coupled plasma atomic emission spectrometry

建立电感耦合等离子体发射光谱(ICP-AES)法和粉末压片制样-X射线荧光光谱(XRF)法联合测定石灰岩中游离二氧化硅含量。准确称取经105℃烘干2 h的石灰岩样品0.1000 g,置于30 mL聚四氟乙烯坩埚中,加入8m L浓磷酸,置于300℃电热板上沸腾20 min,冷却后定容在100 mL容量瓶中,静置12 h。采用ICP-AES测定溶解在溶液中的二氧化硅含量,采用XRF测定石灰岩中二氧化硅总含量,用总的二氧化硅含量减去溶液中二氧化硅的含量就得出了游离二氧化硅的含量。经4种标准物质验证,游离二氧化硅含量分析结果与标准值满足规范中相对误差允许限的要求。该方法操作步骤更为简便,分析速度快,低含量游离二氧化硅结果准确度高,适用于批量石灰岩样品中游离二氧化硅含量分析。

A method for the determination of free silica in limestone by inductively coupled plasma atomic emission spectrometry(ICP-AES)and powder pellet sample preparation-X-ray fluorescence spectrometry(XRF)was established.The limestone samples(0.1000 g)dried at 105℃for 2 h were placed in a 30 mL polytetrafluoroethylene crucible,added with 8 mL concentrated phosphoric acid,and placed on a 300℃electric heating plate for boiling for 20 min.After cooling,the samples were fixed in a 100 mL volumetric flask and stood for 12 h.The content of silicon dioxide dissolved in the solution was determined by ICP-AES,and the total content of silicon dioxide in limestone was determined by XRF.The content of free silicon dioxide was obtained by subtracting the content of silicon dioxide in the solution from the total silicon dioxide content.After verification by four standard substances,the analysis of free silica content analysis and standard values meet the requirements of the relative error allowable limit.The method is more simple in operation,fast in analysis speed,and high in accuracy of low content free silica results,which is suitable for the analysis of free silica content in batch limestone samples.