Effect of calcination temperature for magnesite on interaction of MgO-rich phases with boric acid

Keiko Sasaki, Sayo Moriyama

研究成果: ジャーナルへの寄稿学術誌査読

28 被引用数 (Scopus)

抄録

Magnesia (MgO), which can be obtained by calcination of natural magnesite, is one of the most effective known sorbents for borate in aqueous solutions. Here we examine the effect of calcination temperature on sorption of borate for MgO-rich phases produced by calcination of magnesite at 873-1373 K. Calcination at or above 1273 K produced a single magnesium oxide phase, whereas basic magnesium carbonates (mMgCO3·nMg(OH)2· xH2O) formed in association with magnesium oxide at or below 1073 K. Calcination temperature directly affected the efficiency of decarbonation of magnesium carbonate, and the solubility and basicity of magnesium oxide in the resultant calcined products. These factors (along with the boron concentration) essentially control the immobilization mechanism of borate on the calcined MgO-rich phases. After sorption of borate on products calcined at lower temperatures, different types of basic magnesium carbonates were formed that are less effective at immobilizing borate. At low borate concentrations, under saturation for magnesium borate hydrate (Mg7B4O 13·7H2O), co-precipitation of borate with Mg(OH)2 predominates. However, as magnesium borate hydrate becomes supersaturated, both precipitation of Mg7B4O 13·7H2O and co-precipitation with Mg(OH) 2 contribute significantly to borate immobilization. Calcination temperature is a key practical factor affecting the borate sorption efficiency by changing the immobilization mechanism.

本文言語英語
ページ(範囲)1651-1660
ページ数10
ジャーナルCeramics International
40
1 PART B
DOI
出版ステータス出版済み - 1月 2014

!!!All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • セラミックおよび複合材料
  • プロセス化学およびプロセス工学
  • 表面、皮膜および薄膜
  • 材料化学

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