NEUTRALIZATION AND REMOVAL OF COMPOUNDS CONTAINING FLUORIDE IONS FROM WASTE SILICA GEL

作者：Iljina Aliona^*; Baltakys Kestutis; Baltakys Marius; Siauciunas Raimundas

来源：Romanian Journal of Materials, 2014, 44(3): 265-271.

• silica gel
• waste
• fluoride
• aluminum fluoride trihydrate
• neutralization

In this work the possibility of neutralizing or removing compounds containing fluoride ions from waste silica gel was investigated. The elution of F ions from waste silica gel to the liquid medium was performed under static and hydrothermal conditions. It was determined that waste silica gel consists of silicon dioxide (77.77%) and other compounds containing 8.64% F and 4.03% Al3+ ions, which are stable during the drying process (50 degrees C; 48 h). It was determined that under static elution conditions it is possible to remove only 6-7 wt. % F ions into a liquid medium from waste silica gel. It was found that CaO additive has a positive influence on the decomposition of AIF(3)center dot 3H(2)O and the formation of CaF2. It was found that silica gel is a prospective raw material for synthesis of Z-phase because the kinetics of compound formation is faster than in pure mixtures. A principal technological scheme has been designed for waste silica gel neutralization and utilization by using Ca(OH)(2) under static or hydrothermal conditions.

• 出版日期2014