海南新生代玄武岩熔融及析晶性能研究

STUDY ON MELTING AND CRYSTALLIZATION PROPERTIES OF CENOZOIC BASALT IN HAINAN PROVINCE

玄武岩纤维是玄武岩矿石经熔融、拉丝形成的连续纤维,是中国重点发展的四大纤维之一,其原料的熔融及析晶性能对玄武岩纤维制备工艺至关重要。海南北部玄武岩资源丰富,但利用率不高,本次研究采用ICP-OES,XRD,SEM,EDS,DSC方法分析研究了海南新生代玄武岩的化学组成、物相、晶体形貌及熔融特征和析晶性能,为海南玄武岩纤维的研究提供有利参考。研究结果表明:海南新生代玄武岩熔融温度为1317~1356℃,与SiO_(2)含量呈正相关,与CaO含量呈负相关;与拉斑玄武岩相比,碱性玄武岩在较低温度下即可产生液相;玄武岩中橄榄石等高熔点矿物,使其完全熔融温度更高。随玄武岩中MgO含量增高,熔融体中矿物的结晶度和晶粒尺寸均呈下降的趋势。当w(MgO)高于7.66%时,主要析出透辉石;当w(MgO)低于7.66%时,主要析出普通辉石;Fe_(2)O_(3)含量越高,析晶后晶粒尺寸越大。

The basalt fiber,a kind of continuous fiber,formed by melting and drawing is one of the four major fibers developed in China.The melting and crystallization properties of its raw materials are very important to the preparation process of basalt fiber.This paper studies the abundant basalt resources in northern Hainan and put an emphasis on the promotion of utilization rate of basalt fiber resources.Therefore,ICP-OES,XRD,SEM,EDS and DSC are used to analyze the chemical composition,phases,crystal morphology,melting characteristics and crystallization properties of the Cenozoic basalt from Hainan in an attempt to provide a favorable reference for the study of Hainan basalt fiber.The results show that the melting temperature of Cenozoic basalt in Hainan is 1317 to 1356℃,which is positively correlated with the content of SiO_(2) and negatively correlated with the content of CaO.Compared with tholeiite,alkaline basalt can produce liquid phase at lower temperature,while the presence of high melting point minerals such as olivine in basalt make it a higher melting temperature.With the increase of MgO content in the basalt,the crystallinity and grain size of the minerals in the molten body tend to decrease.When the content of w(MgO)is higher than 7.66%,diopside is mainly precipitated;when the w(MgO)was lower than 7.66%,common pyroxene is mainly precipitated.Furthermore,the content of Fe_(2)O_(3) in the basalt also plays a role in the crystallinity and grain size of the minerals-the higher the Fe_(2)O_(3) content is,the larger the grain size is.