Method for preparing non-sintered shell-wrapped ceramsite using solid waste meanwhile immobilizing heavy metal in river sediment, and non-sintered river-sediment-based ceramsite

A method for preparing a non-sintered river-sediment-based shell-wrapped ceramsite using solid waste meanwhile immobilizing a heavy metal in river sediment, comprising the steps of:

• (1) dehydrating the river sediment and compacting to obtain a dry cake-shaped residual soil, and grinding the dry cake-shaped residual soil, to obtain a dry powdery residual soil;
• (2) mixing the dry powdery residual soil with a solid waste powder and an alkali activating powder material, to obtain a mixture;
• (3) subjecting the mixture to a first granulation, to obtain first grade cold-bonded ceramsites;
• (4) sieving the first grade cold-bonded ceramsites to obtain first grade cold-bonded ceramsites having a particle size of not less than 1 mm and not more than 3 mm, and first grade cold-bonded ceramsites having a particle size of larger than 3 mm but not more than 5 mm, and performing a second granulation on the first grade cold-bonded ceramsites having a particle size of not less than 1 mm and not more than 3 mm, and the first grade cold-bonded ceramsites having a particle size of larger than 3 mm but not more than 5 mm, to obtain second grade cold-bonded ceramsites, wherein a mass ratio of the first grade cold-bonded ceramsites having a particle size of not less than 1 mm and not more than 3 mm to the first grade cold-bonded ceramsites having a particle size of larger than 3 mm but not more than 5 mm is in a range of (2-1):(1-2);
• and
• (5) mixing the second grade cold-bonded ceramsites with a sulfoaluminate cement and a Portland cement, and subjecting a resulting mixture to a third granulation, to obtain the non-sintered river-sediment-based shell-wrapped ceramsite,
• wherein based on a total mass of the dry powdery residual soil, the solid waste powder, and the alkali activating powder material being 100%, a mass content of the dry powdery residual soil is in a range of 70-80%, a mass content of the solid waste powder is in a range of 15-25%, and a mass content of the alkali activating powder material is in a range of 5-10%;
• an adhesive is added during the first granulation and the second granulation;
• a mass ratio of the sulfoaluminate cement to the Portland cement is in a range of (7-9):(3-1);
• and
• a mass ratio of the second grade cold-bonded ceramsites to the sulfoaluminate cement is in a range of 3:1 to 3:2.