Leaching of rare earths from fine-grained zirconosilicate ore

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;,2;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.