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广泛分布于我国南方泥盆纪地层的“宁乡式”铁矿储量巨大,然而含磷高严重制约了该类型铁矿的开发利用.铁矿石中磷的赋存状态是设计该类型铁矿“提铁降磷”方案的理论基础,是开发该铁矿首先要了解的问题.充分利用湿化学全岩分析、电感耦合等离子体质谱分析等全岩元素分析,扫描电子显微镜、X射线衍射等物相分析,电子探针微分析、激光剥蚀电感耦合等离子体质谱分析等微区分析技术,对鄂西晚泥盆世含磷鲕状铁矿石中磷的赋存状态、物质来源与磷矿物形成过程进行了初步探讨.铁矿石中的含磷矿物主要为碳氟磷灰石,分别以短柱状磷灰石晶体颗粒(65%以上粒径小于20μm)、磷灰石内碎屑(粗砂至极粗砂级,集中形成透镜状或带状层理)以及鲕粒中与赤铁矿相互包裹的凝胶状磷灰石(层厚度10~50μm)3种形式存在.磷灰石晶体是在孔隙水中重结晶而生成,磷质可能来源于晚震旦世地层的磷块岩;磷灰石内碎屑是古海水体中原位化学沉积的产物,磷质可能来源于古海周边的大陆;鲕粒中凝胶状磷灰石也是原位化学沉积的产物,但与铁质沉积位置相同,并与富铁的鲕绿泥石混合或相互包裹形成鲕粒.
Widely distributed in the Devonian strata in southern China “Ningxiang type ” iron ore reserves are huge, however, the high phosphorus content restricts the development and utilization of this type of iron ore. The occurrence of phosphorus in iron ore is the design of this type Iron ore “iron lifting ” scheme is the theoretical basis for the development of the iron ore to understand the first thing.Taking full advantage of wet chemical rock analysis, inductively coupled plasma mass spectrometry and other rock analysis, scanning electron microscopy, X-ray diffraction and other phase analysis, electron probe microanalysis, laser ablation inductively coupled plasma mass spectrometry and other micro-area analysis technology, the late Ordovician phosphorus ore oolitic iron ore phosphorus state, material Source and phosphorus mineral formation.Phosphorus and fluorine apatite is the main phosphorus-bearing minerals in iron ore, which are respectively composed of short columnar apatite crystal particles (65% particle size less than 20μm), apatite There are three forms of intragranular detritus (grit to gritty, concentrated lenticular or ribbon bedding), and gelatinous apatite (layer thickness 10 ~ 50μm) that are mutually encased with hematite in oolites Apatite crystals are formed by recrystallization in pore water, and phosphorus is possible Phosphorite from Late Sinian strata. Apatite debris is the product of in-situ chemical deposition in ancient seawater. Phosphorus may originate from the continent around the ancient sea. Gel-like apatite in ooids is also in situ The product of chemical deposition, however, is in the same location as the iron deposits and is mixed or co-encased with the iron-rich alcula chlorite to form ooids.