石英砂表面铁胶膜的形成——温度和老化时间的影响

摘要

Iron cutans coated on the surface of quartz sand were synthetized at initial pH 7 and iron mole ratio R [Fe( II )/Fe( Ⅲ) ] 0.1 to investigate the influence of the temperature and the aging time of the synthetic systems on the formation of iron oxides in the cutans and further providing the formation mechanism of iron cutans. The compositions and morphologies of the minerals in the synthesized cutans were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results showed that when the quartz sand amount was 10 g and the aging time was 25 d, the peak intensity of goethite in XRD patterns increased successively and the crystalline shape of iron oxide in the cutans analyzed by SEM became increasingly bigger with the increase of temperature from 30℃ to 90℃ . When the quartz sand amount was 10 g and the aging temperature was 60℃, the peak intensity of goethite in XRD patterns increased successively during the first 18 days, and then decreased and tended to become stable. The crystalline shape of goethite in the cutans analyzed by SEM increased during the first 18 days and reached the maximum on the 18th day, and then decreased gradually along with the increase of aging time.%以石英砂为载体,在pH值为7和铁摩尔比R为0.1的条件下合成了石英砂表面针铁矿胶膜,并探讨了不同温度和老化时间对针铁矿胶膜形成的影响,以揭示铁胶膜的形成机理.利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对合成胶膜样品分别进行矿物成分和形态的分析.研究结果表明:当石英砂添加量为10 g、老化时间为25 d时,随着温度由30、50、70增加到90℃,胶膜中针铁矿的XRD蜂强度明显增强,SEM图像中针铁矿的结晶程度逐渐增强,品形逐渐变大；当石英砂添加量为10 g、老化温度为60℃时,随着老化时间的延长,胶膜中针铁矿的XRD峰强度先逐渐增强,矿物品形也先逐渐增大(前18 d),18d左右时矿物的晶形较大且较均一,18 d之后XRD峰强度逐渐减弱并趋于稳定,晶形又逐渐变小.