Leaching of rare earths from fine-grained zirconosilicate ore

Abstract Leaching of rare earths Y, La and Ce by sulphuric acid from fine-grained zirconosilicate ore was investigated using Taguchi method of experimental design. An orthogonal array of L 8 , 2 7 which denotes 7 factors at 2 levels was chosen to consider the various factors relevant to the leaching process: baking time, baking temperature, acid dosage, leaching time, leaching temperature, grind size and dilution. Statistical analysis showed that sulphation baking was a significant step for the leaching of rare earths from the whole-of-ore and optimized leaching of rare earths involved the following condition: baking for 3 h at 320 °C at 3.2 g acid/g ore acid dosage followed by water leaching at 20 °C for 1 h and dilution of 20 mL water/g ore using 300 um grind size. The effect of each leaching factor was also discussed.