基于磁化焙烧处理的高岭土磁选除铁增白工艺的研究

Improvement of Magnetic Iron Removal and Whitening of Kaolin based on Magnetizing Roasting

以贵州某地高岭土为研究对象,采用湿法球磨对磁化焙烧强化高岭土磁选除铁增白工艺进行了研究。在湿法球磨浆料体系中,以0.2%无水碳酸钠和0.2%六偏磷酸钠为助磨剂,研究了浆料体系的不同pH值及不同球磨时间对磁选精矿产率的影响。结果表明,当浆料体系在pH值为9,球磨时间为30min时,磁选精矿磁选产率可达84.4%,煅烧白度为87.4%,通过XRD图谱及化学组成综合分析可知,磁选精矿中矿物形式以高岭石的为主,含少量的偏高岭石;磁选铁杂质矿物存在形式以石英、磁铁矿为主,二者以胶结的形式存在,湿法球磨不易将其剥离而以胶结的形式一同磁选出。

Effects of wet milling on the magnetizing roasting-based iron removal and whitening of kaolin were studied using Guizhou kaolin as raw material. The slurry system for wet milling contained 0.2% anhydrous sodium carbonate and 0.2% sodium hexametahposphate as grinding aids. The effects of different pH value of the slurry system and different milling time on the productive rate of magnetic concentrate were observed. The results showed： when the pH value of the slurry system was about 9 and the milling time was about 30 minutes, the productive rate of magnetic concentrate was up to 84.4%, and the calcined whiteness was about 87.4%. Analysis of the XRD spectrum and the chemical composition revealed the main component of the magnetic concentrate was kaolinite with a small amount of metakaolinite; the removed iron impurities were mainly quartz and magnetite in cementation, which were difficult to be separated by wet milling but only to be magnetically picked out in cementation.