逐步加热κ-T实验的磁性矿物学应用  

Magnetic mineralogical applications of stepwise heatingκ-T experiments

作　　者：谌微微 张灵敏 刘沛瑜 邬睿童 CHEN Weiwei;ZHANG Lingmin;LIU Peiyu;WU Ruitong(School of Ocean and Earth Science,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学海洋与地球科学学院,上海200092

出　　处：《中国矿业》2024年第8期238-246,共9页China Mining Magazine

基　　金：同济大学实验教改项目资助(编号:1350104103);国家自然科学基金面上项目“西太平洋采薇海山及周边海域深海沉积的环境磁学研究与第四纪底层水演化”资助(编号:42177422)。

摘　　要：磁性矿物鉴定在矿产预普查及研究成矿模式中发挥了重要作用。常规磁性矿物鉴定实验(磁化率随温度变化磁学实验,简称κ-T实验)通常采用室温至700℃的单循环加热-降温模式,对于中间温度循环磁化率的变化特征缺乏捕捉点。针对该缺陷,本文设计了逐步加热κ-T实验,以检测磁性矿物在不同加热阶段的转化过程,为准确鉴别磁性矿物种类提供可靠依据。本文同时结合等温剩磁获得曲线(IRM)实验、退磁强度衰减(J/J_(max))实验等岩石磁学实验和扫描电镜(SEM)、能谱分析(EDS)实验,对逐步加热κ-T实验鉴定结果进行验证和补充。实验结果表明:逐步加热κ-T实验可提供传统κ-T实验缺失的磁性矿物转化细节,结合矫顽力特征、解阻温度和SEM与EDS结果,可明确鉴定出地质样品的磁性矿物类型。Magnetic mineral identification plays an important role in mineral pre-census as well as in the study of mineralization patterns.Conventional magnetic mineral identification experiments(magnetization versus temperature,calledκ-T experiment)usually use a single-cycle heating-cooling mode from room temperature to 700℃,which lacks a capture point for the characteristics of the magnetic susceptibility changes in the intermediate temperature cycles.To address this deficiency,a stepwise heatingκ-T experiment is designed in this paper to detect the transformation process of magnetic minerals in different heating stages,providing a reliable basis for the accurate identification of magnetic mineral species.In this paper,the results of the stepwise heatingκ-T experiments are validated and supplemented with the rock magnetism experiments,such as isothermal remanent magnetization(IRM)and demagnetization(J/J_(max)),as well as scanning electron microscopy(SEM)and energy spectrum analysis(EDS)experiments.The experimental results show that the stepwise heatingκ-T experiments can provide the details of magnetic mineral transformation that are missing in the traditionalκ-T experiments,and combined with the coercivity characteristics,the blocking temperature,and the SEM and EDS results,the magnetic mineral types of the geological samples can be clearly identified.

关 键 词：κ-T实验 磁性矿物 磁学实验 扫描电镜 能谱分析 

分 类 号：TD91[矿业工程—选矿] P575.9[天文地球—矿物学]