高炉排锌及其回收利用之探讨

Discussion on the Zinc recovery and utilization of blast furnace

锌在高炉炼铁中属有害杂质,高炉锌负荷应小于150g/t。锌对高炉运行的影响主要表现在破坏原燃料性能、降低煤气利用率、加速风口中小套损坏、损坏炉缸砖衬等方面。高炉内的锌是由入炉的原燃料带入的,并通过炉内、炉外两个循环富集加大了高炉的锌负荷。锌主要由高炉煤气带出炉外,积存在瓦斯灰和除尘灰等固废中。如要降低高炉的锌负荷,充分利用高炉煤气除尘净化后的固体废弃物,实施炉外循环进行回配,就必须回收利用瓦斯灰、除尘灰中的ZnO。介绍了从瓦斯灰和除尘灰中提取ZnO的工艺技术,锌的总提取率可达85%以上。提锌后的瓦斯灰和除尘灰,ZnO含量大幅度降低,对实现炉外固废的循环利用,降低锌负荷,稳定高炉冶炼操作起到促进作用。

Zinc is a kind of harmful inclusion in blast furnace iron smelting, and the zinc load for blast furnace should be smaller than 150g/t. Its influence on blast furnace operation is mainly represented in the aspects of damaging raw and fuel materials performance, reducing gas utilization rate, speeding up the destroy of the small sleeve in tuyere and damaging brick lining in furnace hearth. The zinc in blast furnace is brought in by coming-in-furnace raw and fuel materials, and the zinc load is increased by the two circular enrichments both in and out of furnace. Zinc is mainly brought out of furnace by blast furnace gas and accumulated in solid waste such as gas ash and dust-collecting ash. ZnO in gas ash or dust-collecting ash must be recovered and utilized if we want to reduce the zinc load of blast furnace, fully utilize the solid waste in blast furnace gas after dust removal and realize back proportion through out-of-fur- nace circulation. It is introduced the technology to extract ZnO from gas ash and dust-collec- tion ash, the total extract rate can reach over 85 percent. The content of ZnO in gas ash and dust-collection ash has been reduced to a large extent. And that plays a promote role in reali- zing circular out-of-furnace solid waste utilization, reducing zinc load, steadying operation of blast furnace.