Application of Taguchi method in the optimization of dissolution of ulexite in NH4Cl solutions

The Taguchi method was used to determine optimum conditions for the dissolution of ulexite in NH4Cl solutions. The ranges of experimental parameters were between 50-87°C for reaction temperature, 0.05-0.20 g·mL-1 for solid-to-liquid ratio, 1-4 M for NH4Cl concentration, 5-25 min for reaction time, and (-850+600)-(-90) μm for particle size. The optimum conditions for these parameters were found to be 87°C, 0.05 g·mL-1, 4 M, (-300+212) μm, and 18 minutes, respectively. Under these conditions, the dissolution percentage of ulexite in NH4Cl solution was 98.37. Reaction products were found to be boric acid, ammonium tetraborates, sodium tetraborate decahydrate, calcium chloride, and sodium chloride.