电炉钛渣碱浸除硅、铝与碱浸渣的预氧化焙烧动力学

采用碱浸除杂-预氧化焙烧-活化改性-高压酸浸工艺处理云南地区电炉钛渣，制备高品位人造金红石. 研究了电炉钛渣碱浸除硅、铝的机理，考察了搅拌速率、粒度、温度、NaOH浓度、液固质量比、浸出碱试剂单因素对浸出率的影响，SiO2与Al2O3浸出率高达75%和50%；正交实验结果表明，NaOH浓度为1.5 mol/L、液固质量比为8、温度为沸腾温度(92.7℃)、浸出时间为1 h的条件下，浸出效果较理想；通过碱浸渣预氧化，有60%的TiO2以金红石形态析出，且在低于700℃下过程受界面化学反应控制，扩散较快，表观活化能为31 kJ/mol/, 850℃下过程受扩散控制，随空气流量增大氧化率提高.

Removal of Silicon and Aluminum from EAF Titanium-containing Slag and Pre-oxidization Roasting Kinetics of the Leached Slag

The process route of alkali leaching-oxidative modification at high temperature-high pressure acid leaching for preparing high grade synthetic rutile was proposed for treatment of electric-titanium slag of Yunnan. The removal mechanism of silicon and aluminum from EAF titanium-containing slag was studied. The effects of single-factors including stirring speed, particle size, temperature, NaOH concentration, mass ratio of liquid to solid, alkaline reagent on the leaching rate were examined. The leaching rates of SiO2 and Al2O3 reached up to 75% and 50%. The effective sequence of temperature, NaOH concentration, mass ratio of liquid to solid, and time was investigated by orthogonal experiments. The results show that the leaching effect is well under the conditions of NaOH concentration of 1.5 mol/L, mass ratio of liquid to solid of 8, the boiling temperature, and leaching time of 1 h. There are 60% of the rutile TiO2 crystallized from the slag after alkaline leaching by pre-oxidation, the process was controlled by the interfacial chemical reactions under 800℃, the diffusion rate is faster, and the apparent activation energy 12 kJ/mol.