铁酸锌气体还原的热力学分析

Thermodynamic analysis of the reduction of zinc ferrite with CO-CO_2

根据热力学原理,计算并分析了含锌冶金粉尘中的重要成分Zn Fe2O4在CO-CO2气体还原过程中的热力学行为.Zn Fe2O4的气体还原遵循逐级还原规律,且Zn Fe2O4很容易被CO还原到Zn O和Fe3O4.较高温度条件下,Zn O的气体还原易于Fe O的还原.随着反应温度升高,锌完全反应和挥发所需要的CO含量不断降低,当反应温度从1100 K升高到1400 K时所需的CO体积分数由0.4降低到0.01以下.要达到还原分离金属锌的目的,不必将铁氧化物还原到金属铁,而只需将铁氧化物还原到Fe3O4或Fe O,同时满足锌的还原条件即可.在高炉炉身中上部,由于发生锌的还原反应和内部循环,给高炉生产带来危害,因此应减少和控制高炉的锌负荷.

The reduction behavior of zinc ferrite, an important constituent of zinc-bearing metallurgical dust, with CO- CO2 gas was calculated and analyzed according to the thermodynamic principles. The reduction of ZnFe204 obeys a stepwise mechanism. ZnFe204 is easy to be reduced to ZnO and Fe3 04. ZnO is easier to be reduced than FeO, and a lower volume fraction of CO gas is needed to reduce ZnO at a higher temperature. If the reaction temperature increases from 1100 K to 1400 K, the reducing potential expressed by the volume fraction of CO decreases from 0.4 to 0. 01. Aiming to the reduction and separation of metallic zinc from zinc- bearing dust, it is not necessary to reduce iron oxides to metallic iron, but Fe3 04 or FeO, while zinc oxide should be reduced to metal- lic zinc. In the upper of the blast furnace, zinc reduction and internal circulation occur and bring harms to blast furnace production, and therefore the zinc load of the blast furnace should be reduced and controlled strictly.