Method for preparing SBA-15 molecular sieve and recovering fluorine by using fluorine-containing silicon slag

The invention discloses a method for preparing an SBA-15 molecular sieve and recovering fluorine by using fluorine-containing silicon slag. The method comprises the following steps: 1) dissolving the fluorine-containing silicon slag in a sodium hydroxide solution to obtain a solution A; 2) uniformly mixing a template agent, concentrated hydrochloric acid and water according to a certain proportion to obtain a solution B; (3) adding the solution A into the solution B under a stirring condition, continuously stirring, and then transferring into a hydrothermal reaction kettle for crystallization; 4) performing liquid-solid separation after crystallization to obtain a solid C and a filtrate D, washing and drying the solid C, and roasting for a certain time to obtain the SBA-15 molecular sieve; and 5) adding metal salt into the filtrate D for reaction, and performing liquid-solid separation to obtain metal fluoride and a sodium salt solution. The method has the characteristics that the SBA-15 molecular sieve is lo