钒钛磁铁精矿冷固球团催化还原机理

Catalyzing the direct reduction of cold-bound pellets from titanomagnetite concentrate

对添加剂催化钒钛磁铁精矿冷固球团直接还原行为进行了详细的研究 ,包括添加剂种类和用量及催化剂催化还原机理 .研究结果表明 :在 1 0 50～ 1 1 0 0℃ ,m(C)∶m(Fe)为 0 .5～ 0 .6 ,还原时间 3h的条件下 ,添加DA 2催化剂与常规的Na2 SO4或Na2 CO3相比 ,钒钛磁铁精矿冷固球团煤基直接还原所得产品的金属化率提高 3 .1 %～ 4 .6 % ;该金属化球团经磨矿磁选进行铁和钒钛分离时 ,所得磁性产品 (直接还原铁粉 )中铁的品位提高 5 .30 %～ 5 .43 % ,非磁性物中TiO2 ,V2 O5 的品位分别提高 2 .76 %～ 3 .87%和 0 .2 7%～ 0 .45 % ,TiO2 ,V2 O5 的回收率分别提高 1 4 .68%～1 3 .0 8%和 4.1 3 %～ 6 .97% .SEM及XPS等微观测试结果表明 :添加剂DA 2的作用机理为加速铁氧化物还原 ,促进铁晶粒的长大 ,降低还原球团中MFe与TiO2 晶粒嵌布的紧密程度 。

The catalyzing effect of additives on the direct reduction of cold bound pellets from titanomagnetite concentrate was studied in detail, which covered the dosage of four kinds of additives and the corresponding catalyzing mechanism. It is shown that the percent metallization of reduced pellets is improved by 3.1%～4.6% when DA 2 is added, compared with addition of Na 2SO 4 or Na 2CO 3 and under the conditions of reduction temperature 1 080 ℃, m (C)∶ m (Fe) 0.58 and reduction duration 3 h. The separation of iron from vanadium and titanium was carried out successfully through magnetic concentration of finely ground metallized pellets, and the results have been achieved as follows: the grade of iron in magnetic concentrate is increased by 5.30%～5.43%, the grade of vanadium and titanium increased by 2.76%～3.87% and 0.27%～0.45%, and the recovery increased by 14.68%～13.08% and 4.13%～6.97% in the non magnetic tailings, respectively. The results of SEM and XPS determination have proved that the function of additive DA 2 lies in accelerating iron oxide reduction and enhancing the growth of metal iron crystal, the tightness of paragenesis among metal iron, vanadium and titanium oxide being loosened, and the separation of iron from vanadium and titanium being improved.