Removal of zinc from basic oxygen steelmaking (BOS) dusts by leaching with organic acids

To alleviate the environmental contamination and utilise the iron resource of basic oxygen steelmaking (BOS) dusts, the recycling of the wastes has to be addressed. Zinc in the wastes is harmful to the operation of steelmaking processes and needs to be removed before they are recycled. Leaching with an organic acid can be the most economical and environmentally friendly hydrometallurgical method for treating the steelmaking wastes, because organic acids are widely available, can be recycled, and can be biodegraded in environment. The aim of the project was to identify an organic acid which was highly efficient in selectively removing zinc over iron from BOS dusts so that the waste materials can be recycled to substitute a part of raw materials for steelmaking in iron and steelmaking processes. The effects of leaching conditions on the zinc leaching behaviour were investigated to gain better understanding of leaching mechanism. Lixiviate reuse was studied to maximize the leaching rate of zinc.