利用X射线衍射、傅里叶变换红外光谱和扫描电镜等分析测试手段对铜渣在煅烧过程中的多相转变进行研究。结果表明:铜渣原渣从800℃开始发生物相转变,由Fe2SiO4转变为Fe3O4和非晶SiO2,Fe2SiO4向Fe3O4的转变在1 000℃结束。850℃时开始发生Fe3O4向α-Fe2O3的转变,1 050℃时转变基本完成,1 000~1 050℃是Fe3O4向α-Fe2O3转变的主要温度区间。Fe2SiO4向Fe3O4的转变和Fe3O4向α-Fe2O3的转变在850~1 050℃同时发生。Fe2SiO4煅烧生成的非晶SiO2从900℃开始析晶,析晶产物为石英晶体,1 000℃时开始发生石英向方石英的转变。与煅烧时间的延长相比,煅烧温度的升高对Fe3O4转变为α-Fe2O3更有利,但煅烧时间的延长使生成的α-Fe2O3颗粒大小更均匀,颗粒形状更接近于球形。
Multiphase transformation during the process of copper slag calcination was studied by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope. The results show that the transformation of Fe2SiO4 into Fe304 and amorphous SiO2 in the initial copper slag takes place when the temperature is about 800 ~C. The transformation of FeaSiO4 into Fe304 is completed at about 1 000 ~C. The transformation of Fe304 into ct-Fe203 occurs within a wide temperature range from 850 to 1 050 ~C. The transformation of Fe2SiO4 into Fe304 and Fe304 into a-Fe203 occurs simultaneously over temperatures between 850-1 050 ~C. Amorphous SiO2 generated from Fe2SiO4 decomposition begins to crystallize at 900 ~C. The product of amorphous SiO2 crystallization is identified as quzrtz. The transformation of quartz into cristobalite takes place at 1 000 ~C. Compared with the prolonging of calcination time, the increase in calcination temperature is benefitial for the transformation of Fe304 to ~t-Fe203. The prolonging of calcination time makes the grains of ct-Fe203 more uniform in size and spherical in shape.