Abstract: In order to make full use of serpentine tailings resources,microwave pretreatment method was used to carry out an experimental study on the enhanced leaching of serpentine tailings. The influence of microwave pretreatment time,power,reaction time,reaction temperature,sulfuric acid concentration and liquid-solid ratio on the leaching effect was investigated,and the enhancement mechanism was analyzed by XRD,SEM,specific surface area and pore structure. The optimum processing parameters were determined by single factor test as microwave pretreatment time of 3 min,microwave power of 400 W,reaction temperature of 90 ℃ ,reaction time of 30 min,sulfuric acid concentration of 4. 0 mol / L,liquid-solid ratio of 4 mL / g. Under these conditions,the leaching rates of MgO and TFe in serpentine can reach 97. 19% and 70. 57%,respectively. Compared with traditional mechanical stirring leaching,microwave pretreatment can shorten the reaction time from 90 min to 30 min without reducing the leaching rate. The mechanism analysis shows that microwave heating removes the hydroxyl group in serpentine,reduces the structure order and crystallinity of magnesium hydroxide octahedron,and increases the dissolution rate and dissolution rate of magnesium and iron in acid. The results provide a new idea for efficient recovery of valuable components in serpentine.

Key words: serpentine,microwave pretreatment,leaching,recycling and ultilization