Na₂O, K₂O, SiO₂ and Al₂O₃ release from potassic and calcic–sodic feldspars into alkaline solutions

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• 作者：Francisco Locati ; Silvina Marfil ; Edgardo Baldo ; Pedro Maiza
• 关键词：C. Alkali release ; D. Feldspars ; B. Microstructure ; D. Alkalis ; C. Alkali– ; aggregate reaction
• 刊名：Cement and Concrete Research
• 出版年：2010
• 出版时间：August 2010
• 年：2010
• 卷：40
• 期：8
• 页码：1189-1196
• 全文大小：1944 K

文摘

The potential release of elements from potassic and calcic–sodic feldspars into the concrete pore solution was evaluated by ICP-MS using 1 N NaOH and KOH solutions at 80 °C in accordance with the conditions set in the chemical test method. Materials were characterized by petrography, XRD and by XRF analysis. The influence of textural and microstructural characteristics on the leaching process was also analyzed by immersing polished plates of each mineral in 1 N NaOH at 80 °C for 7 days. Optical microscope and SEM observations indicate that microstructural characteristics, such as cleavage zones, twins, grain–grain contact and the finer and less abundant phases in perthites, play a key role in the leaching process under alkaline conditions. Na₂O, K₂O, SiO₂ and Al₂O₃ are supplied by hydrolysis, although the participation of other processes cannot be ruled out.