Interlayer Cations Distribution Models for Hydrothermal K-NH4 Dioctahedral Mica Series : Verification and Application

正如Drits等人所指出的，K-NH_4双八面体云母系列的层间阳离子分布模式以及由此产生的I-T(伊利石-托贝利特)层间体系是一个有趣的话题。(1997年)。为了更好地区分这种层间体系，本研究基于随机(无序)、规则(有序)和分离等不同的I-T层间模型进行了X射线衍射计算剖面模拟。结果表明，这些层间结构分别具有005反射峰展宽的特征，并由005(2Å)和002(5Å)反射峰宽与层间NH4比(或I/T比)的比值所决定。随着层间NH_4含量的增加，峰宽比逐渐增大，并在NH_4=0.5时出现极大值，但在层间NH_4=0.5时，分离层间的展宽效应是陡峭的，并成倍放大。对于有序的中间层，…但加宽效应不明显，在中间I/T比(NH_4=0.2-0.3和NH_4=0.7-0.8)附近出现双峰。为了验证I-T层间体系的X射线衍射分析判据，对天然和合成K-NH4云母系列样品进行了研究。与叶蜡石矿床(荷洛矿)和锡脉矿床(圣何塞矿)伴生的天然样品介于随机I-T间层和有序I-T间层之间。相反，合成云母系列更接近于有序的I-T层理。通过前处理将蒙皂石组分层转化为类云母组分层(伊利石或托贝利石)，也可将I-T-S层间体系分析为I-T层间体系。将这些I-T-S中间层用1N氯化钾或氯化铵溶液在150℃下浸泡6h，然后在相对湿度为0%的控制条件下进行大气X射线衍射，结果令人满意。较少

Interlayer cations distribution modes of K-NH_4 dioctahedral mica series and resulting I-T (illite-tobelite) interstratified system are an interesting topic as noted by Drits et al. (1997). In order to discriminate such interstratified system more closely, XRD calculated profile simulation has been made on the basis of different I-T interstratified models such as random (disordered), regular (ordered) and segregated in the present study. The results indicate that these interstratified structures are individually most characteristic of broadening of the 005 reflection and are determinative by the reflection peak width ratio of the both 005 (2Å) and 002 (5Å) reflections against the interlayer NH_4 ratio (or I/T ratio). The peak width ratio is enlarged gradually with the interlayer NH_4 ratio and show a maxima at NH_4=0.5 for the both random and segregated interstratifications although the broadening effect is steep and doubly magnified in the latter. For the ordered interstratification, … More however, the broadening effect is less pronounced and shows bimodal maxima around intermediate I/T ratio (NH_4=0.2-0.3 and NH_4=0.7-0.8).Natural and synthetic K-NH_4 mica series samples have been investigated to test and verify the XRD analytical criteria for I-T interstratified system. Natural samples associated with pyrophyllite deposit (Horo mine) and tin-vein deposit (San Jose mine) are of intermediate character between random and ordered I-T interstratifications. In contrast, synthetic mica series are rather closer to ordered I-T interstratification. The I-T-S interstratified system can also be analyzed as I-T interstratified system when the smectite component layer is converted to mica-like component layer (illite or tobelite) through pretreatment procedure. When these I-T-S interstratified ones are to be soaked with 1N KC1 or NH_4Cl solution at 150℃ for 6 hours; then x-rayed in atmosphere under controlled condition of relative humidity of 0%, the results are excellently satisfied. Less