Method for preparing ceramsite by using municipal sludge as raw material

A method for preparing ceramsite by using municipal sludge as a raw material, comprising:

• (1) drying:
• concentrating, digesting, mechanically dehydrating and drying the municipal sludge to obtain a raw sludge;
• wherein the step of the digesting comprises:
• removing a biodegradable organic matter in the municipal sludge by a common anaerobic process;
• (2) preparing ingredients:
• taking the ingredients according to the following parts by weight:
• 80-120 parts of the raw sludge, 10-20 parts of fly ash, 1-5 parts of kaolinite, 10-20 parts of steelmaking slag, 5-15 parts of zeolite, 1-5 parts of hematite, 5-15 parts of calcareous shale, 5-20 parts of waste incineration fly ash, 0.5-2 parts of Fe2O3, 1-4 parts of waste glass, 0.1-2 parts of calcium carbonate, 0.1-2 parts of sodium lauryl sulfate, 0.1-1.5 parts of sodium benzoate, 0.1-0.5 part of nano zirconia, 1-5 parts of kaolinite porcelain clay;
• 2-4 parts of silicon nitride;
• and 1-4 parts of calcium oxide;
• (3) mixing and stirring the ingredients uniformly to obtain stirred materials, putting the stirred materials into a granulating machine for a granulation to obtain material pellets, and controlling a particle size of the material pellets to range from 15 mm to 20 mm;
• (4) drying the material pellets after the granulation at 90-110° C. for 1-2 hours to obtain dried material pellets, then preheating the dried material pellets at 220-280° C. for 10-20 minutes to obtain preheated material pellets, then transferring the preheated material pellets to a sintering device for a sintering to obtain sintered material pellets, and then cooling the sintered material pellets to obtain cooled materials;
• (5) discharging the cooled materials, and crushing large chunks of the cooled materials into crushed materials with a maximum particle size of 20-26 mm;
• and
• (6) separating and screening the crushed materials to obtain a first ceramsite having a particle size of 5-15 mm, a second ceramsite having a particle size of 15-26 mm, a ceramic sand having a particle size of 0.5-5 mm, and a fine powder having a particle size of less than 0.5 mm.