Optimization of tungsten leaching from low manganese wolframite concentrate using Response Surface Methodology (RSM)

In the present work, the pressure leaching of low-grade wolframite concentrate (33.61 wt% WO3) with average particle size of 62 μm obtained from Chahpalang mine located in the Yazd province of Iran was studied. The Effects of temperature, time and Na2CO3/WO3 weight ratio on tungsten leaching efficiency were evaluated by Response Surface Method (RSM) and Central Composite Design (CCD). The predictions of statistical model showed that the leaching temperature has the major effect on tungsten leaching efficiency with respect to other leaching factors. Increasing the temperature up to 210 °C lead to the increase of tungsten leaching efficiency while resulted in decreasing of leaching efficiency from 210 °C to 230 °C. Optimum conditions by utilizing desirability function follows: 202-208 °C temperature, 3.0-3.7 h, 3.68-4.27 Na2CO3/WO3 weight ratios. The experimental results showed that a leaching efficiency of > 95% under these optimum leaching conditions can be obtained.