浓硫酸焙烧钛渣提钛后的滤渣提硅实验研究

Experimental Research on Silicon Extraction from the Filter Residue in the Process of Titanium Extraction of Roasted Titanium Slag with Concentrated Sulfuric Acid

研究了从钛渣经浓硫酸焙烧提钛后的滤渣中提硅制备硅酸钙产品的工艺条件,主要工序包括碱溶和钙化。碱溶过程考察了NaOH与滤渣质量比、碱溶温度、碱溶时间以及液固质量比对滤渣中SiO_2提取率的影响,得到的最佳工艺条件为:碱溶温度190℃、NaOH与渣质量比3∶1、液固比4.5∶1、碱溶时间60 min;此条件下滤渣中SiO_2提取率可达74.09%;钙化过程考察了反应温度和反应时间对硅酸钠钙化率的影响,得到的最佳工艺条件为:反应温度100℃、反应时间45min,此条件下硅酸钠的钙化率可达94%。产品硅酸钙粉末含44.36%CaO,主要物相为CaSiO_3,粉末形貌疏松多孔,粒度为微米级。

The process conditions were investigated of silicon extraction and calcium silicate preparation from the filter residue in the process of titanium extraction of roasted titanium slag with concentrated sulfuric acid. The main process steps include alkali-solution and calcification. The effects were investigated of NaOH-residue mass ratio, reaction temperature, reaction time and liquid-solid mass ratio on SiO2 extraction rate from the filter residue during alkali-solution. The optimum operating conditions of alkali-solution are obtained as follows： reaction temperature of 190 ℃ ,NaOH-residue mass ratio of 3 ： 1 ,liquid-solid mass ratio of 4.5 ： 1 and reaction time of 60 min. And SiO2 extraction rate is 74.09 % under the above conditions. The effects were investigated of reaction temperature and reaction time on calcification rate of sodium silicate solution during calcification. The optimum operating conditions of calcification are obtained as follows： reaction temperature of 100 ℃ and reaction time of 45 min. And the calcification rate of sodium silicate solution is 94% under the above conditions. Calcium silicate powder product contains 44.36% CaO and its main phase is CaSiO3 ,having loose and porous morphology and micron-level particle size.