Study on the New Melting Process of Iron-and Steel-making Dust

巴西合作研究人员研究了高炉炼铁和电弧炉过程中产生的粉尘的物理化学性质。对于不含锌的电炉粉尘，用含碳材料制成的冷结球团具有足够的强度和还原能力，而且不会发生膨胀和爆裂，是气体还原和熔融还原工艺的理想原料。对于含有相当数量的复合尖晶石(锌、铁、锰)Fe_2O_4的电炉粉尘，研究了其强度和还原性能。结果表明，当加热到1060℃时出现异常膨胀，当加热到1200℃以上时，95%的锌被脱除，约70%的锌在熔融还原过程中蒸发成氧化锌并集中在粉尘中。得到的粗锌可作为锌冶炼的原料。日方合作研究人员正在开发一种分离ZI…的焦炭过滤工艺更多的NC来自铁。在该方法中，电炉烟尘中复杂的尖晶石结构的锌可以在1000℃以上的移动焦床中蒸发，并在冷凝器中以液态锌的形式回收。另一方面，铁在焦床中以固体状态还原，与焦炭一起排放，在常规或熔融还原炼铁工艺中回收。从而通过使用焦炭填充床实现高效分离。然而，电弧炉粉尘中含有大量的亚微米颗粒。在这项研究中，我们利用焦炭过滤过程的冷态模型来研究这种亚微米颗粒的过滤。此外，还对利用化学反应从熔渣中回收热能和均匀粒度的细渣颗粒进行了基础性研究。利用转杯雾化器的准热态模型对石蜡雾化进行了研究，并对高温熔渣进行了雾化试验。石蜡雾化得到的细小颗粒均匀(约0.7 mm)，矿渣粉化也得到细小颗粒，为开发实用工艺提供了积极的依据。较少

Brazilian cooperative researchers studied physico-chemical properties of dusts generated in both BF ironmaking and EAF processes. For the former which does not contain zinc, cold bonded pellets having carbonaceous materials, produced from the dust are reported to have enough strength and reducibility as well as no swelling and broken out therefore being proved as sound raw materials for both gas reduction and smelting reduction processes.For the EAF dust which contains considerable quantity of the complex spinel of (Zn, Fe, Mn)Fe_2O_4, strength and reducibility have been studied. As the results, abnormal swelling was found to occurs when it was heated to 1060C, 95%Zn was removed when it was heated over 1200C, and about 70% Zn was vaporized as ZnO and concentrated in dust when it was processed in smelting reduction. The crude zinc obtained can be used as raw materials for zinc smelting.Cooperative researchers in Japanese side are developing a coke filter process for the separation of zi … More nc from iron. In this method, zinc contained in the EAF dust as complex spinel structure can be evaporated in coke moving bed heated over 1000 C and recovered as liquid zinc in a condenser. On the other hand iron is reduced in the coke bed in solid state and discharged together with coke and recovered in conventional or smelting reduction ironmaking processes.Behavior of over micron particles has been studied in our lab. resulting in high efficiency separation by using a coke packed bed. However, EAF dust contains high quantity of sub micron particles. In this study, we investigated filtration of such sub micron particles by using a cold model of the coke filter process. However, complete result has not yet obtained.In addition, a fundamental study has been made on the recovery of thermal energy from molten slag together with uniformly sized fine slag particles applying chemical reaction. Atomization of wax was studied by using a quasi-hot model of a rotating cup-atomizer and atomization of high temperature molten slag has also tested. Fine particles of considerably uniform size (about 0.7mm) were obtained for wax atomization and fine particles were also obtained for slag pulverization, which provided a positive basis for developing a practical process. Less