河北某高岭土矿除铁工艺比较研究

Comparative Study on Iron Removal Process of a Kaolin Mine in Hebei Province

河北某高岭土矿SiO2为33.78%~61.69%,Al2O3为22.27%~35.27%,TFe为1.91%~18.70%,属于硅铝酸盐矿。铁含量较高使得矿物不能直接利用,需要进行除铁增白。通过比较草酸和硫酸两种酸浸去除法,发现硫酸酸浸效果更好。硫酸酸浸试验条件优化为:硫酸质量分数为32%,酸浸时间3 h,温度60℃,液固质量比5∶1。该条件下高岭土的除铁率高达97.6%。除铁后样品的综合指标满足QB/T 1635-2017《日用陶瓷用高岭土》中的合格品标准。

The main mineral composition of the Hebei kaolin is SiO2(33.78%-61.69%),Al2O3(22.27%-35.27%),and TFe(1.91%-18.70%),belonging to a aluminosilicate ore.The mineral can't be directly used because of the high content of iron,so that it is necessary to carry out iron removal and whitening.After comparing oxalic acid and sulfuric acid,the experimental optimization conditions were:H2SO4 concentration of 32%,leaching time of 3 h,temperature of 60℃,and liquid-solid mass ratio of 5∶1.Under this condition,the iron removal rate can be as high as 97.6%.The comprehensive index of the samples after iron removal can meet the qualified product standard of the QB/T 1635-2017 kaolin for daily ceramics.