焙烧活化对煤矸石中硅元素浸出的影响

摘要

The coal gangue is a kind of solid waste from coal mining and separating, which is harmful to the environment. It contains a large number of silicon and silica which account over 45% content. If managed and utilized properly, it will be still a useful resource. In this paper, the coal gangue collected from a coal mine was selected as raw materials for leaching silica. Calcination will greatly affect the activity of coal gangue. Effects of particle size of coal gangue, mix ratio of raw materials, calcination temperature, treatment time on activity of product were discussed. The results showed when coal gangue powder was grind to 180~250μm, the coal gangue and composite alkali were uniformly mixed (mcoal:malkali= 4 : 1) and roasted for 120 mins at 700 ℃, white carbon black was obtained by acid soaking, alkali treatment, secondary acidification, drying, high-temperature roasting, the productivity could reach 88%, and the purity was over 99%.%煤矸石是采煤和洗煤过程中排出的固体废物，会对环境造成危害，但是煤矸石中含有大量硅元素，其质量分数在45%以上，如果加以适当的处理和利用，仍是一种有用的资源。以煤矸石为硅源焙烧活化制备白炭黑，焙烧过程对煤矸石的活性影响较大，对焙烧过程中的粒度、配料比、温度和时间等影响因素进行讨论，实验结果表明：将煤矸石粉磨至180～250μm，煤矸石与复合碱按照m（煤矸石）：m（复合碱）=4∶1的比例混匀，700℃下焙烧120 min，经酸浸、碱溶、二次酸化后，再烘干、焙烧即得纯度在99%以上，SiO2的浸出率达88%以上。