Publication Details

Hamano, T., Shen, R., Zhang, G., Brown, P. & Ostrovski, O. (2010). Processing of manganese furnace dust: Drying and zinc oxide reduction. INFACON XII (pp. 143-154). Finland: Outotec Research Center.


Manganese furnace dust collected in smelting of manganese alloys is in the form of a slurry containing oxides of manganese, iron, zinc and other metals, and organics. The water content of the sludge is in the range of 55-60 wt%. Average carbon content, measured by LECO analysis, which includes carbon in the organics and carbonates is 20 wt%. The dust contains (average) 33.4 wt% Mn and 1.3 wt% Zn (dry basis). Currently, manganese furnace dust is accumulated in large ‘settling ponds’. Major factors preventing recycling of the manganese furnace dust to the ferroalloy furnace are handling, due to its high water and organics contents, and the long term accumulation of zinc in the furnaces, which can cause irregularities in their operation. Drying of manganese furnace dust and removing zinc from the dust are important steps to recycle the dust to the smelting furnaces. This paper presents results of drying tests of manganese dust under different conditions and zinc removal from dried dust in sintering experiments. The drying tests were conducted in a muffle furnace at 423 to 973 K in air. On the basis of drying tests, an empirical relationship correlating the moisture content and drying time with temperature and sample thickness was derived. Zinc oxide was reduced by organics in the furnace dust above 1073 K. The reduction rate increased with increasing temperature with almost complete zinc removal at 1373 K. The effects of sintering time, temperature, moisture content, gas atmosphere, gas flow rate, thickness of a sample, and addition of manganese ore to the dust on zinc removal in sintering experiments have been established.

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