Leaching of low grade zinc oxide ore bearing iron

Alkaline leaching and sulfuric acid leaching of low grade zinc oxide ore bearing iron were studied in this work.The effecting factors,such as leaching time in different leaching agents and leaching temperature using ammonia-ammonium chloride as leaching agent,on zinc and iron leaching rates were investigated in alkaline leaching.The effecting factors,such as the initial sulfuric acid concentration,liquid-solid ratio,leaching temperature in different initial sulfuric acid concentrations and leaching time in different leaching temperatures,on zinc and iron leaching rates were studied in sulfuric acid leaching.The results showed that the leaching rates of zinc and iron were less than 50% and zero in alkaline leaching,respectively,while their leaching rates were greater than 87% and 45% in sulfuric acid leaching.The results of XRD analysis indicated that smithsonite was leached from the ore in alkaline leaching or in sulfuric acid leaching with low initial concentration such as less than 60 g/L or shorter time such as less than 10 min,and smithsonite and siderite were leached from the ore in sulfuric acid leaching with high initial concentration such as greater than 60 g/L or longer time such as more than 10 min.