Extraction of Valuable Components from Alkali Fused Blast Furnace Slag Containing High Concentration of Titanium by Two Leaching Methods

Aiming at the problems of high energy consumption and high economic cost for the extraction of TiO₂ from blast furnace slag containing high concentration of titanium by alkali fusion,the slag was roasted with sodium hydroxide at a lower temperature to extract Si and Al components firstly making TiO₂ enriched in the slag,then the TiO₂ component was abstracted by dilute sulfuric acid.The effects of alkali fusion conditions on the extraction rate of SiO₂ and Al₂O₃ from blast furnace slag containing high concentration of titanium respectively by two leaching processes,air cooling-water leaching and water quenching were investigated.Furthermore,the influence of acidolysis conditions on TiO₂ extraction was also studied in this paper.Under the optimum conditions of alkali fusion at 500℃ for 150 min with 1.5 of alkali addition coefficient,the extraction rate of SiO₂ and Al₂O₃ were separately 56.41% and 89.00% by air cooling-water leaching while respectively 63.45% and 86.25% by water quenching.The acidolysis rate of TiO₂ was 91.21% at the conditions of 50% for mass fraction of sulfuric acid,1.25~1.5:1 for mass ratio of acid to slag,160~170℃ and 2.0 h respectively for temperature and time of acidolysis process.