Production of Zinc Oxide from Willemite Containing Ore from Kabwe Town in Zambia

High-purity zinc oxide (> 99 weight %) was obtained from complex zinc silicate ore of Kabwe town of the Central province of ZambiaZambia. The material was leached with sulphuric acid at varying pH to form zinc sulphate. There was partial dissolution of silica during leachingLeaching. The following parameters were studied; leachingLeaching temperature, pH, and solid to liquid ratio. Leach efficiency of 97% was obtained. Zinc was recovered from solution via precipitationPrecipitation with sodium hydroxide, magnesium oxide, and oxalic acid. Low-grade zinc oxide was obtained during precipitationPrecipitation with sodium hydroxide and magnesium oxide owing to co-precipitationPrecipitation of SiO2. On the other hand, there was no co-precipitationPrecipitation of SiO2 during precipitationPrecipitation with oxalic acid such that high-purity zinc oxalate was obtained. The precipitated zinc oxalate was heated up at 500 °C to obtain zinc oxide with purity of more than 99%.