Response surface methodology was used to optimize the defluorination process of steam-enhanced microwave roasting waste cathode carbon

Abstract

As a typical hazardous solid waste, improper treatment of waste cathode carbon (WCC) will cause great harm to animals and plants and their living environment. In order to make the treatment of WCC more simple, efficient and clean, this paper mainly adopts the method of microwave roasting and introducing water vapor to make the fluoride in WCC melt at high temperature and be absorbed by water vapor. The effects of water flow rate, reaction temperature, reaction time, material particle size and other important factors on the defluorination efficiency of WCC were studied by single factor experiment. In this paper, the response surface method (RSM) was used to obtain and verify the best results of the experiment, and the optimum process conditions of water vapor enhanced microwave roasting WCC defluorination were determined: the reaction temperature was 1100 °C, the reaction time was 2.8 h, and the water flow rate was 3.2 mL·min⁻¹. Under this condition, the defluorination effect of WCC is the best. The predicted value of defluorination efficiency of WCC is 99.85 %, and the actual value is 99.8 %.