含钛高炉渣在碱熔过程中Ti、Si、Al元素赋存状态的变化

以攀枝花含钛高炉渣为原料,采用氢氧化钠碱熔法分离炉渣中的有价组分,通过对碱熔过程中不同反应阶段所形成的碱熔渣及水浸渣的结构和谱学特征进行分析和表征,研究不同温度条件下原始矿物相及中间产物的化学反应过程,揭示含钛高炉渣碱熔过程中各有价组分赋存状态的变化。结果表明:在碱熔过程中,283℃时,含钛高炉渣中透辉石相结构被破坏,Si~(4+)离子形成Na_2SiO_3可溶性盐和中间产物CaMgSiO_4,随着反应的进行,CaMgSiO_4进一步与NaOH发生反应生成难溶物Na_2CaSiO_4;当碱熔温度升高到296℃时,镁铝尖晶石中Si~(4+)与NaOH反应生成可溶性盐Na_2SiO_3;当碱熔温度为320℃时,钙钛矿晶体结构开始被破坏,Ti~(4+)离子与NaOH作用生成难溶物Na_2TiO_3,经水浸后Na_2TiO_3晶形被破坏,变为无定型结构残留于水浸渣中。

Changes in Occurrence State of Ti,Si and Al Elements in Ti-bearing Blast Furnace Slag during Alkali Melting Process

By sodium hydroxide melting process,separation of components from Ti-bearing blast furnace slag in Panzhihua was conducted in this paper.The chemical reaction processes of the original mineral phase and intermediate products at different temperatures were investigated by analyzing the structure and spectroscopic characteristics of the alkali melting slag and water leaching slag formed at different reaction stages,revealing the changes in occurrence state of the components in Ti-bearing blast furnace slag during the alkali melting process.The results show that at 283 ℃ the diopside phase in the slag is damaged,and the soluble salt Na2SiO3 and intermediate product CaMgSiO4 can be formed due to the reactions between Si4+ and NaOH.With the reactions progressing,CaMgSiO4 further reacts with NaOH to generate insoluble Na2CaSiO4.When the reaction temperature is up to 296 ℃,the Si4+ in magnesia-alumina spinel reacts with NaOH to form Na2SiO3.When the alkali fusion temperature is 320 ℃,perovskite phase begins to decompose,and Ti4+ reacts with NaOH to generate insoluble Na2TiO3,which remains in the leaching slag as amorphous structure after Na2TiO3 structure is destructed by water leaching.