蒙脱石向海绿石转变的“海绿石化”模拟研究

发布时间：2018-03-24 04:02

本文选题：海绿石　切入点：蒙脱石　出处：《地质论评》2017年02期

【摘要】：海绿石是一种浅海相沉积指示矿物,形成成熟的海绿石需1Ma。本文以含铁量很低的蒙脱石和0.1mol/LFe~(3+)、0.2mol/LK~+的离子溶液分别为初始物质在50℃恒温环境和不同的pH、Eh条件下,模拟海绿石化过程,并通过XRD、FTIR、SEM、ESR等检测反应产物。研究发现,在SEM下观察到球形纳米颗粒的海绿石出现;同时XRD谱图上除出现云母类矿物的001衍射峰外,还出现d值为0.1520nm和0.1498nm的代表海绿石和铁伊利石的060特征衍射峰。pH和氧化还原条件对产物的影响比较显著,pH为酸性时出现海绿石和铁伊利石的组合,其红外吸收谱中出现AlFe~(2+)OH或Mg~(2+)Fe~(3+)OH(3547~3562cm~(-1))、Fe~(3+)Fe~(3+)OH的伸缩振动峰,与之相应的ESR中出现g=1.978的八面体位Fe~(3+)的共振峰;当pH介于中性的时候,红外光谱谱图上出现明显的AlFe~(2+)OH、Mg~(2+)Fe~(3+)OH(3550~3562cm~(-1))和Al~(3+)Fe~(3+)OH(870cm~(-1))振动;pH为碱性时,出现Fe~(3+)Mg~(2+)OH(3560cm~(-1))振动;上述红外吸收振动的出现表明Fe~(3+)已经进入了蒙脱石结构的八面体位。蒙脱石在上述条件下发生明显的改变,发生海绿石化或铁伊利石化,pH和氧化还原条件对结果的影响比较显著,酸性的环境中海绿石化显著,而中性至碱性的环境则发生铁伊利石化。
[Abstract]:Glauconite is a neritic sedimentary mineral indicating, mature glauconite the iron content of 1Ma. in the very low montmorillonite and 0.1mol/LFe~ (3+), 0.2mol/LK~+ ion solution were the initial material in constant temperature of 50 DEG C environment and different pH conditions, Eh, simulation of glauconite process, and through XRD, FTIR. SEM, ESR and other products was detected. The study found that the spherical nano particles were observed by SEM in the glauconite; at the same time XRD spectrum in addition to the 001 diffraction peak of mica minerals, also appeared D value for 0.1520nm and 0.1498nm on behalf of glauconite and illite iron 060 characteristic diffraction peaks of.PH and oxidation reduction the conditions on the product significantly, pH is a combination of glauconite and illite occurs when acid iron absorption, AlFe~ in the infrared spectrum (2+) or OH Mg~ (2+) Fe~ (3+) OH (3547~3562cm~ (-1)), Fe~ (3+) Fe~ (3+) stretching vibration peak of OH, and the the corresponding G=1.978 ESR in the eight position of Fe~ (3+) of the resonance peak; when pH is neutral, infrared spectrum was AlFe~ of (2+) OH, Mg~ (2+) Fe~ (3+) OH (3550~3562cm~ (-1)) and Al~ (3+) Fe~ (3+ (OH) 870cm~ (-1)) vibration; pH is the basic, Fe~ (3+) Mg~ (2+) OH (3560cm~ (-1)) of the infrared absorption of vibration; vibration show that Fe~ (3+) has entered the eight tetrahedral structure of montmorillonite. The montmorillonite changed obviously under the above conditions, occurrence of glauconitization iron or illite, effects of pH and redox conditions on the results of the more significant, acidic environment in Green Petrochemical is significant, and neutral to alkaline environment to have iron illite.

【作者单位】：南京大学内生金属成矿机制研究国家重点实验室南京大学地球科学与工程学院;
【基金】：国家重点基础研究发展计划(编号:2012CB822001) 国家自然科学基金项目(编号:41672037)的成果~~
【分类号】：P578.963

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