Preparation method of composite inorganic coagulant for tobacco wastewater treatment

The invention provides a preparation method of a composite inorganic coagulant for tobacco wastewater treatment, which comprises the following steps: putting a reducing agent ferrous salt into a container, and adding a proper amount of concentrated sulfuric acid to prepare a ferrous sulfate solution; adding an alkali metal salt stabilizer into the ferrous sulfate solution, and continuously stirring; slowly adding an oxidizing agent while continuously stirring the solution to obtain a polyphosphate ferric sulfate coagulant; and carrying out room temperature polymerization on a sodium silicate solution, adding the prepared polymeric phosphorus ferric sulfate coagulant into the sodium silicate solution, curing, continuously stirring, and curing to obtain the polymeric silicon phosphorus ferric sulfate coagulant. The polysilicon phosphorus ferric sulfate coagulant provided by the invention has relatively high removal rates on COD, chroma, ammonia nitrogen and phosphate in raw wastewater and biochemical effluent o