提出一种从黑泥中回收利用钛的新工艺,该工艺包括NaOH水热转化、水洗和H2SO4浸出制备TiO2。在优化的反应条件下,即NaOH溶液浓度为50%(质量分数)、NaOH/黑泥质量比为4:1、反应温度为240°C、反应时间为1 h和氧气分压为0.25 MPa,钛转化率可达97.2%,主要含钛产物是Na2TiO3。非目标产物Na2TiSiO5在水洗中保持稳定,在水热反应中提高NaOH浓度可以抑制Na2TiSiO5的生成。水热产物经过水洗后,97.6%的Na^+可以回收。含有NaOH的溶液经过浓缩之后可以回用。在较低温度下,水洗物料中96.7%的钛能被较低浓度的硫酸浸出得到钛液。利用所得钛液进一步制备合格TiO2产品。
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.