盐酸浸出自然冷却含钛高炉渣

Leaching behavior of air cooled Ti-bearing blast-furnace slag in hydrochloric acid

对盐酸浸出自然冷却的含钛高炉渣的行为进行了研究。结果表明:高炉渣中镁铝尖晶石最先浸出,其次是攀钛透辉石和富钛透辉石,钙钛矿的浸出速度最慢。镁铝尖晶石和透辉石的溶解导致高炉渣破碎成细小颗粒,其主要物相是钙钛矿。透辉石溶解形成的硅酸析出并包裹在未反应的高炉渣表面。当钛的浸出率超过22%以后,浸出速度显著下降,这是钙钛矿的反应活性差以及硅酸的包裹所致,而钙钛矿的反应活性差可能是浸出速度显著下降的主要原因。在20%盐酸溶液中于100℃下经8h浸出,钛的浸出率仅为44%。机械球磨可以显著强化高炉渣中钛的浸出,采用边磨边浸的方法,钛的浸出率可达72%。行星球磨强化浸出的主要原因是富钛透辉石与攀钛透辉石的选择性机械活化以及高炉渣的细化作用;边磨边浸具有更好的细化效果,加速了钙钛矿的溶解,因而对钛浸出的强化效果更好。

The leaching behavior of air cooled Ti-bearing blast-furnace slag in hydrochloric acid was investigated. The results show that the dissolution rate of various minerals in the slag decrease in the following order of spinel, diopside and perovskite. Along with the rapid dissolution of spinel and diopside, the slag break into quantities of small particles, in which the perovskite is the dominant species, The silicic acid dissoluted by diopside precipitate out and coat upon the surface of the un-reacted slag. The dissolution remarkedly slows down when the dissolved percentage of Ti is in excess of 22% due to lower reactivity of the perovskite and the coverage from silicic acid, of which the former may be the primary reason, In 20% hydrochloric acid solution at 100 ~C, the dissolved percentage of titanium atter 8 h is only 44%. Milling operation considerably accelerates the leaching processs. With a combined milling and leaching, the maximum Ti extraction rate reaches 72%. The enhanced dissolution produced by planetary ball milling is mainly due to selectively mechanical activation of diopside, The simultaneous milling and leaching have a better comminution effect, which accelerate the dissolution of the perovskite, thus exhibit a higher enhancement effect.