Deepening of hydration chemistry of silicates by in-situ analysis under wet conditions

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02487
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26060:Metals production and resources production-related
• Research Institution: Tohoku University
• Principal Investigator: Shibata Hiroyuki 東北大学, 多元物質科学研究所, 教授 (50250824)
• Co-Investigator(Kenkyū-buntansha): 助永 壮平 東北大学, 多元物質科学研究所, 准教授 (20432859) ; 川西 咲子 東北大学, 多元物質科学研究所, 助教 (80726985)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: シリケート構造 / 重合度 / 溶出 / ケイ酸塩物質 / 蛍光イメージング

Outline of Final Research Achievements

This research was performed with the aim of elucidating the elution mechanism of the constituent elements of silicate substances. Elution tests were conducted on a total of 15 types of samples in the CaO-SiO2 binary system and the ternary system in which MgO, FeO, CaF2 or Al2O3 was added to the binary system, and the samples were analyzed by various spectroscopic analyses. As a result, it was found that the silicate skeleton structure and network structure have a great influence on the Ca elution, which leads to an increase in pH. It was also clarified that the rate-determining step of Ca elution is the diffusion of Ca ions in the Ca-depleted layer near the surface. As described above, the elution behavior of the silicate substance into water was elucidated, and the effectiveness of the addition of the third component for suppressing the elution was shown.

Free Research Field

高温物理化学

Academic Significance and Societal Importance of the Research Achievements

国内外の溶出挙動に関する研究の多くは、スラグを想定した複合相を用いた溶出挙動の評価であるのに対し、本研究では高温合成により得られた鉱物単相を試料とした。これにより、シリケートの骨格構造やネットワーク構造とCaおよびSi溶出量との関係の解明や、添加成分の溶出抑制への有効性の理解に至った。ケイ酸塩物質の有効活用を実現するためには、利用環境下での化学耐久性や反応性への多様化するニーズに応える必要があり、本研究を通じて得られた基礎知見は材料設計への指針のひとつになりうる。