葡萄糖酸钠对镁渣碳化行为的影响机理

Mechanism of Sodium Gluconate on Carbonation Behavior of Magnesium Slag

摘要:

通过开展温度变化、pH值演变、CO₂吸收量及抗压强度测试，并结合X射线衍射（XRD）、热重分析（TG-DTG）、傅里叶变换红外光谱（FTIR）、扫描电镜（SEM）和低场核磁共振（LF-NMR）等分析手段，系统探究了葡萄糖酸钠（SG）掺量对镁渣（MS）碳化过程的作用机理。结果表明：适量SG可促进MS中钙、镁离子的溶出，进而促进碳化反应进行。MS抗压强度的提升得益于SG对于碳化产物晶体形貌的改善以及孔隙率的降低。当SG掺量为1%时，MS碳化24 h后的抗压强度较空白组提升47.1 MPa，孔隙率降至6.47%；当SG掺量增至3%和5%时，MS碳化产物减少，孔隙率增大，抗压强度显著下降。

Abstract:

Temperature variation， pH value evolution， CO₂ absorption amount， and compressive strength tests were carried out， and analytical techniques including X-ray diffraction （XRD）， thermogravimetric analysis （TG-DTG）， Fourier transform infrared spectroscopy （FTIR）， scanning electron microscopy （SEM）， and low-field nuclear magnetic resonance （LF-NMR） were employed to systematically investigate the effect of varied sodium gluconate （SG） dosages on the carbonation process of magnesium slag （MS）. The results show that an appropriate amount of SG can promote the dissolution of calcium and magnesium ions from MS， thereby facilitating the carbonation reaction. The increase in the compressive strength of MS by SG is attributed to the improvement in the crystal morphology of the carbonation products and the reduction in porosity. When the SG dosage is 1%， the compressive strength of MS after 24 h of carbonation increases by 47.1 MPa compared to the blank group， and the porosity decreases to 6.47%. When the SG dosage is increased to 3% and 5%， the formed amount of carbonation products in MS are decreased， and the porosity is increased. Consequently， the compressive strength is significantly dropped.