由钛铁矿制备SCR催化剂载体TiO_2的优化试验

Optimization Experiments on Preparation of TiO_2 as a SCR Catalyst Carrier from Ilmenite

以钛铁矿为原料,通过硫酸法固相酸解制取二氧化钛(TiO2)具有较高的酸解率。在钛液水解过程中,添加适量乙二胺四乙酸可促进钛铁分离。超声波的机械作用和空化效应有助于进一步除去微量的杂质离子。采用X射线荧光能谱分析、BET比表面积与孔隙度分析、及扫描电子显微镜分析研究了EDTA及超声波对TiO2颗粒的优化作用,并制备以不同TiO2为载体的SCR催化剂进行脱硝活性测试。结果表明:EDTA在钛液水解阶段可以起到很好的除铁效果,从而缩短工艺流程,提高TiO2纯度。超声波在提高除杂效果的同时可降低TiO2的粒度,优化其分散性能,进而使SCR催化剂具备更优的脱硝催化活性。

Preparation of titanium dioxide （ TiO2 ） by solid-phase digestion of ilmenite in sulfuric acid has a high acidolysis rate. Since Ethylene Diamine Tetraacetie Acid（EDTA） is a widely used complexing agent, appropriate amount of EDTA added during hydrolysis of titaniferous solution can be beneficial to the separation of titanium and iron. The mechanical and cavitation effects of ultrasound can contribute to further remove a trace amount of impurity ions. The effects of EDTA and ultrasound on TiO2 are analyzed by carriers are tested. The results show that the addition of EDTA can restrain the hydrolysis of Fe3＋ , thus shorten the whole process and improve TiO2 purity; uhrasound is helpful to remove impurity ions, and can reduce the particle sizes of TiO2 and optimize their dispersion properties at the same time. The SCR catalyst utilizing the optimized TiO2 as a carrier presents better catalytic activity.