【摘要】 为了解决硫酸法生产钛白存在严重的大量硫酸废水污染问题,提出了NaOH水热法分解钛铁矿以浸出钛的全新工艺,研究了钛铁矿在NaOH水热体系中的分解行为及动力学。确定最佳的反应条件为:反应温度240℃,NaOH浓度400 g·L^-1,液固比3.5:1,氧分压0.5 MPa,反应时间2 h,搅拌速度600 r/min,粒度<75μm,钛的浸出率可达到95%以上。通过XRD和SEM表征,确定了钛铁矿的分解行为及钛酸钠的物相组成。宏观动力学研究表明,钛铁矿中的钛在NaOH水热体系中的氧化分解过程符合未反应收缩核模型,过程速度受产物层扩散控制,计算得到浸出过程的表观活化能为47.39 kJ/mol;钛铁矿在NaOH水热体系中浸出动力学方程为:1-2X/3-（1-X）^2/3=[735.09exp（-47389.8/RT）]t。更多还原

【Abstract】 The leaching behavior and kinetics of ilmenite ore in NaOH hydrothermal system were researched, and an innovative metallurgical process of leaching titanium from ilmenite ore by NaOH hydrothermal method was proposed to overcome the severe dilute H₂SO₄ waste water pollution of current titanium extraction process in industry. Results that the optimal reaction conditions are as follows: the reaction temperature 240℃, NaOH concentration 400 g·L^-1, the mass ratio of alkali to ore 3.5:1, partial oxygen pressure 0.5 MPa, reaction time 2 h, agitation speed 600 r/min, and ore particle size <75μm, and the leaching degree of titanium can reach 95%. Based on XRD analyses and SEM microstructure observation, the decomposition behavior of ilmenite ore was investigated and the generating of sodium titanium particles was observed. The producing phenomenon of the product layer is not found during leaching. The leaching kinetics study shows that the leaching rate of ilmenite ore in NaOH hydrothermal system is controlled by the solid product layer diffusion with the apparent activation energy of 47.39 kJ/mol, and the empirical rate equation is "1-2 X/3-（1-X）^2/3=[735.09 exp（-47389.8/RT）]t".更多还原