Saltpetering treatment liquid and application thereof

The invention provides saltpetering treatment liquid and application thereof. The treatment liquid is prepared from the following raw materials: metal soluble salt, acidic silica sol and a solvent, the metal soluble salt comprises at least one of soluble magnesium salt, soluble aluminum salt, soluble copper salt, soluble zinc salt, soluble titanium salt, soluble tin salt and soluble nickel salt. According to the method, the metal soluble salt and the acidic silica sol are matched for saltpetering treatment, and the metal soluble salt and free alkali react to generate insoluble alkali, so that the content of the free alkali is reduced; meanwhile, due to the generation of insoluble alkali, surface pores of concrete stone can be effectively blocked, and the content of free alkali is further reduced; the acidic silica sol is small in particle size and high in activity, and can react with free alkali, so that the content of the free alkali is reduced; the acidic silica sol forms a hydrophobic protective film on th