<p>A new process for the extraction of SiO₂ by low-temperature roasting with potassium feldspar as raw material and sodium hydroxide and sodium carbonate (NaOH-Na₂CO₃) as auxiliaries was investigated. Under the optimal conditions, the silica extraction rate reached 99.59%. Through the design of alkali ore ratio, NaOH-Na₂CO₃ molar ratio, roasting temperature, roasting time four factors and three levels of orthogonal experiment. The primary and secondary relationships of the effects of various factors on SiO₂ extraction were obtained. The kinetics of SiO₂ extraction from potassium feldspar in NaOH-Na₂CO₃ mixed alkali system was systematically studied. According to the Arrhenius formula, the apparent activation energy of the two reaction stages was calculated, and the reaction equation was determined. It was determined that the front section of the reaction was controlled by the diffusion of the liquid boundary layer and the combination of surface chemistry. As the reaction proceeds, the chemical reaction rate is transformed into surface chemical reaction control. Finally, the chemical composition, phase structure and micro-morphological characterization of the slag showed that the original ore structure was almost destroyed and small holes were formed on the surface of the slag. It is proved again that the SiO₂ in the ore is extracted.</p>