腐植酸改性膨润土在铁矿球团中的应用效果

Application effect of humic acid modified bentonite binder in iron ore pellets

课题组在前期研究中,以腐植酸和钙基膨润土为原料采用半干法制备了腐植酸改性膨润土复合粘结剂。本文通过造球试验、红外光谱分析、接触角测定等方法研究了该复合粘结剂在铁矿球团中的应用效果,探讨了复合粘结剂提高生球强度的内在原因。造球试验表明,相对于单一使用膨润土或腐植酸,使用腐植酸改性膨润土可以显著提高生球强度,在复合粘结剂用量0.5%的条件下,生球落下强度达到3.5次/(0.5 m)。红外分析表明,腐植酸通过羟基、羧基等官能团吸附在膨润土表面,粘结剂中的有机组分使铁矿表面接触角减小,亲水性增强,并且改善了粘结剂在铁矿颗粒间的分散性,有利于生球强度的提高。

In preliminary study,the humic acid modified bentonite composite binder was prepared by using a semi-dry method with humic acids and calcium-based bentonite as raw materials. In this study,the application effects of the composite binder in iron ore pelletizing were investigated by pelletizing test,infrared spectroscopic analysis and measurements of contact angle,and the underlying causes of the composite binder to improve green ball strength were discussed. The pelletizing test shows that,the humic acid modified bentonite can significantly improve the drop strength of green balls compared with the single use of bentonite or humic acid. The drop strength of green pellets with use of 0. 5% composite binder could reach 3. 5 times/（ 0. 5 m）. FTIR analysis illustrates that the humic acid can be adsorbed onto the bentonite surface by such functional groups as carboxyl group and hydroxyl group. The organic component in the binder reduces the contact angle,enhances the hydrophilicity of magnetite concentrate and improves the dispersibility of binder distributed among the iron ore particles,which contributes to the strength of green balls.