Recovery of titanium from undissolved residue(tionite) in titanium oxide industry via NaOH hydrothermal conversion and H_2SO_4 leaching

To recover titanium from tionite, a new process consisting of NaOH hydrothermal conversion, water washing, and H2SO4 leaching for TiO2 preparation was developed. The experimental results show that under the optimum hydrothermal conversion conditions, i.e., 50% NaOH （mass fraction） solution, NaOH/tionite mass ratio of 4：1, reaction temperature of 240 ℃reaction time of 1 h and oxygen partial pressure of 0.25 MPa, the titanium was mainly converted into Na2TiO3, and the conversion was 97.2%. The unwanted product Na2TiSiO5 remained stable in water washing, and its formation was prevented by improving NaOH concentration. In water washing process, about 97.6% of Na＋ could be recycled by washing the hydrothermal product. The NaOH solutions could be reused after concentration. 96.7% of titanium in the washed product was easily leached in H2SO4 solution at low temperatures, forming titanyl sulfate solution to further prepare TiO2.

钛渣消解过程中的不溶残渣在黏土砖中的回收应用

Tionite是在生产TiO2的钛渣消解过程中产生的不溶残渣。它是由金红石、锐钛矿、非晶相和烧石膏组成的细粒度的泥浆,Tionite用作着色剂(高达9%)与成品的Tionite或与经过中和处理后的Tionite混合加入到4种工业黏土坯体中。通过对工业制砖过程进行实验室模拟评定其对技术参数的影响,并测定工作水分、干燥敏感性、收缩和弯曲强度、吸水率、体积密度、风化度和颜色。使用Tionite在技术上是可行的,其对砖性能的影响明显取决于黏土坯体的组成和性能。