氮气保护下热处理胶状黄铁矿的矿物特性演化  

Effect of Heat Treatment in Nitrogen on Mineralogy Characteristics of Colloidal Pyrite

作　　者：李平[1] 陈天虎[1] 杨燕[1] 谢巧勤[1] 谢晶晶[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009

出　　处：《硅酸盐学报》2013年第11期1564-1570,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(41130206;41072035;41172048)项目

摘　　要：长江中下游尤其铜陵地区普遍产出沉积块状硫化物,表现为胶体沉积特征,主要组成为纳米–亚微米的黄铁矿,即胶状黄铁矿,这是一种重要的纳米矿物资源。利用X射线粉末衍射、扫描电子显微镜、热分析仪、磁化率分析仪、原子荧光光谱等,对采自铜陵新桥胶状黄铁矿和普通黄铁矿在氮气保护下不同温度热处理物相、微观形貌、磁化率、砷含量演变规律进行了对比研究。结果表明:胶状黄铁矿在450℃开始相变为单斜磁黄铁矿,起始相变温度比普通黄铁矿低50℃;胶状黄铁矿完全相变温度为500℃,比普通黄铁矿的完全相变温度低100℃;胶状黄铁矿的热分解峰值温度在597℃左右,比普通黄铁矿的热分解峰值低37℃左右;胶状黄铁矿完全相变为磁黄铁矿后磁化率峰值为3180×10–8m3/kg,比普通黄铁矿完全相变为磁黄铁矿的磁化率峰值高1 400×10–8m3/kg;胶状黄铁矿中砷含量为466.5 mg/kg,普通黄铁矿中砷含量为3 086.0 mg/kg,两者相差6.6倍,热处理温度超过700℃时两者都变成为基本无砷的铁硫化物。热处理过程中胶状黄铁矿与普通黄铁矿在相变温度和特性方面的差异表明,纳米到亚微米晶体大小的胶状黄铁矿在煅烧过程中呈现出明显的纳米效应。Colloidal pyrite abundant in the middle and downstream of the Yangzi river especially in Tongling is a sedimentary massive sulfide with colloidal deposition character. Colloidal pyrite mainly composed of nano-sized and submicron-sized particles of pyrite is a nano-geomineral resource. The properties （i.e., phase, micro-appearance, magnetic susceptibility and arsenic content） for colloidal pyrite and common pyrite after heat treatment in nitrogen at various elevated temperatures were investigated by X-ray diffraction, field-emission scanning electron microscopy, thermal analysis, arsenic analysis and atomic force spectroscopy, respectively. The results show that the transformation of colloidal pyrite to pyrrhotite begins at 450 ℃, which is 50 ℃ lower than that of common pyrite. The thorough transformation of colloidal pyrite to pyrrhotite occurs at 〉 500 ℃, which is 100 ℃ lower than that of common pyrite. The temperature of colloidal pyrite decomposition is 〉 597 ℃, which is 37 ℃ lower than that of common pyrite decomposition. The maximum magnetic susceptibility of pyrrhotite derived from colloidal pyrite is 3180×10-8 m3/kg, which is 1 400 × 10-8 m3/kg greater than that of pyrrhotite derived from common pyrite. The arsenic content in colloidal pyrite is 466.5 mg/kg, which is 6.6 times lower than that in common pyrite （3 086.0 mg/kg）. The arsenic content can be ignored when heat treatment temperature is 〉 700 ℃ The relevant difference between colloidal pyrite and common pyrite after heat treatment indicate that the colloidal pyrite crystals could have a nano-sized effect during heating.

关 键 词：黄铁矿 热处理 纳米矿物 纳米效应 

分 类 号：P575[天文地球—矿物学]