Composite conditioner for cadmium pollution remediation of soil , and preparation method and application thereof

The invention belongs to the technical field of soil composite conditioners, and particularly relates to a preparation method and application of a composite conditioner for cadmium pollution remediation of soil in a stone coal mine area. The composite soil conditioner is prepared from granite polished stone powder, municipal sludge, carbide slag, magnesium slag and montmorillonite. The preparation method comprises the following steps: preparing materials according to a mass ratio, crushing, thermally activating, modifying, granulating, and drying to obtain the soil composite conditioner. Solid wastes are used as raw materials, defective crystals and surface porous structures are generated by a thermal activation process, meanwhile, silicon, calcium, potassium and magnesium in the raw materials are partially converted into a citric acid-soluble or water-soluble state, and after modification and granulation, the obtained composite conditioner can significantly reduce available cadmium in soil, reduce accumulati