Desiliconisation of alkaline leaching solution of roasted stone coal with carbonation method

The effects of reaction time, reaction temperature, stirring speed and flowrate of CO2 gas on desilication rate and loss rate of vanadium were studied. The results indicated that desilication rate increases with the increase of flowrate of CO2 gas and reaction time. Reaction temperature and stirring speed have little effect on desilication rate, while influence the loss rate of vanadium significantly. Under the condition of reaction time of 2 h, reaction temperature of 95 °C, stirring speed of 180 r/min, flowrate of CO2 gas of 60 mL/min and aging time of 2 h, desilication rate is more than 96% and the loss rate of vanadium is about 4.24%. The residue of desilication process can be processed for silicon materials, such as high-grade hydrated silica, which commonly known as white carbon black. In addition, with this carbonation method, leaching regents NaOH can be recycled by simple treatments.