Abstract:

The rule of hydrothermal hydrolysis of impurity-bearing titanyl sulfate solution containing [1.0 mol/L TiOSO₄+0.5 mol/L MgSO₄+0.25 mol/L Al₂（SO₄）₃+2.4 mol/L H₂SO₄] was studied.Thermodynamic analysis indicated that the presence of MgSO₄ and Al₂（SO₄）₃ （Mg/Al impurities mainly as MgSO_4（aq） and Al（OH）²⁺ at 110~150 ℃） led to the slight decrease of the theoretical hydrolysis ratios of titanium-bearing spices（150 ℃,99.8%→99.7%）,while the increase of temperature favored the hydrolysis of Ti-bearing spices,from 110 ℃ to 150 ℃ leading to the increase of the theoretical hydrolysis ratio of titanium-bearing spices from 99.1% up to 99.7%.The experimental research indicated that the presence of MgSO₄ and Al₂（SO₄）₃ led to the slight decrease of the hydrolysis of Ti-bearing spices（150 ℃,99.2%→98.3%）,and the increase of temperature favored the hydrolysis of Ti-bearing spices（110→150 ℃,68.6%→98.3%）,which was in good agreement with the thermodynamic analysis results.The agglomerated metatitanic acid particles（with a particle size of 1~3 μm） composed of the small primary particles（with a particle size of 100~300 nm） formed and the corresponding hydrolysis ratio of Ti-bearing spices reached up to 98.3% after treating the impurity-bearing titanyl sulfate solution at 150 ℃ for 10 h.

Key words: titanyl sulfate, hydrothermal hydrolysis, magnesium sulfate, aluminum sulfate, metatitanic acid