菱铁矿热转变过程中岩石磁学性质基本特征

ROCK-MAGNETIC PROPERTIES RELATED TO THERMAL MINERAL ALTERATIONS IN SIDERITE SAMPLES

利用吉林大栗子铁矿纯菱铁矿样品，系统测量了菱铁矿在空气环境下热处理产物的磁化特征．揭示出其饱和等温剩磁（ＳＩＲＭ）、剩磁矫顽力（Ｈ(ｃｒ)）和居里温度（Ｔｃ）随加热温度升高而发生的系列变化，美铁矿氧化过程中准稳定态磁性矿物磁赤铁矿（ｒ－Ｆｅ２Ｏ３）是中间产物之一，并且具有较高的热稳定性．Ｘ射线衍射和穆斯堡尔（Ｍｏｓｓｂａｕｅｒ）效应等分析结果证实了岩石磁学研究所揭示的菱铁矿氧化中磁性矿物转变过程．菱铁矿氧化过程中结晶结构的转变可能会影响其氧化产物的磁性特征．

Rock-magnetic properties were systematically measured on thermal oxidationproducts of siderite samples that were collected from Dalizi iron deposit Jinn province.It was revealed that the isothermal remanent magnetization (IRM), remanencecoercivity (Her) and Curie temperature (TC) of siderite samples varied with differentthermal treatment temperatures. Maghemite (r-Fe2O3) was found to be one of theintermediate Products during siderite oxidation in air atmosphere, and with relativelyhigh thermal stability. The mineral transformations indicated by rock-magnetic methodswere proved by the X-ray diffraction (XRD)and Mossbauer effect experiments. Thecrystalline structure transitions during the siderite oxidation processes might affect themagnetic properties of oxidized siderite samples.