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炉过程中产生的粉尘的物理化学性质。对于前者不含锌，据报道，由粉尘生产的含碳材料的冷粘结球团具有足够的强度和还原性，并且没有膨胀和破裂，因此被证明是气体还原和冶炼还原工艺的良好原料。对含有大量（Zn, Fe, Mn）Fe_2O_4复尖晶石的电炉粉尘进行了强度和还原性研究。结果表明：加热至1060C时出现异常膨胀，加热至1200C以上时脱除95%Zn，冶炼还原时约70% Zn汽化为ZnO并浓缩在粉尘中。所得粗锌可作为锌冶炼的原料。日本的合作研究人员正在开发一种焦炭过滤工艺，用于从铁中分离出锌。该方法可使电炉粉尘中锌以复杂尖晶石结构在1000℃以上的焦炭移动床中蒸发，并在冷凝器中以液态锌的形式回收。另一方面，铁在焦炭床中以固态形式还原，与焦炭一起排出，在常规或冶炼还原炼铁工艺中回收。我们在实验室研究了超微米粒子的行为。实现了焦炭填料床的高效分离。然而，电炉粉尘中含有大量的亚微米颗粒。在这项研究中，我们使用焦炭过滤过程的冷模型来研究这种亚微米颗粒的过滤。然而，完整的结果尚未得到。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研究。采用旋转杯式雾化器的准热模型对蜡的雾化进行了研究，并对高温熔渣的雾化进行了试验。在蜡雾化过程中获得了粒径相当均匀的细颗粒（约0.7mm），在渣粉化过程中也获得了细颗粒，为开发实用工艺提供了积极的基础。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