Immobilized combination agent and method for immobilizing As (III) and heavy metal-containing waste residues by using immobilized combination agent

Abstract

The invention provides an immobilized combination agent and a method for immobilizing As (III) and heavy metal-containing waste residues by using the same. The immobilized combination agent comprises an oxidizing agent, a stabilizing agent, a curing agent and a pH value regulator, and the stabilizing agent is composed of ferric salt, ferrous salt, sulfide, sodium bentonite, light calcined magnesia, rock phosphate powder and calcium carbide sludge. The immobilization method comprises the following steps: crushing and screening original waste residues, and fully mixing and stirring with an oxidizing agent to obtain primary waste residues; adding ferrous salt or ferric salt and sulfide aqueous solution into the first-stage waste residue, and uniformly stirring and mixing to obtain second-stage waste residue; sodium bentonite, calcium carbide sludge, light calcined magnesia, rock phosphate powder and water are added into the second-stage waste residues, and third-stage waste residues are obtained; and adding a curing agent and water into the third-stage waste residue, forcibly stirring, discharging and curing. By means of the method, high-content arsenic and heavy metal (cadmium, lead, copper, zinc, chromium, mercury and the like) in the waste residues can be efficiently fixed, the toxic leaching concentration of the arsenic and the heavy metal is obviously reduced, and the requirement for safe disposal is met.

Description

technical field [0001] The invention belongs to the field of comprehensive treatment of heavy metal pollution, and particularly relates to an immobilization composition suitable for As(III) and heavy metal waste residues and a method for immobilizing the immobilization composition to treat waste residues containing high concentrations of heavy metals. Background technique [0002] With the continuous development of the chemical industry, non-ferrous metal mining, smelting industry and electronics industry, the hazardous waste residues of heavy metals enter the environment and become an important source of pollution. Under the action of erosion and soil erosion, it will cause serious environmental risks to soil and water bodies, and directly threaten the health of the population. At present, the commonly used treatment methods mainly include physical and chemical remediation and bioremediation methods, such as landfill method, leaching (washing) method, foreign soil method, l...

AI Technical Summary

Problems solved by technology

[0006] The traditional curing and stabilizing agents mainly use cement and lime as the main body, but the addition of too much cement will easily lead to an excessively high volumetric ratio, and the strong alkaline environment is not conducive to the fixation of arsenic. As(V) and As(III ) anion exists in the waste residue, most of the immobilization materials are only effective for As(V), but it is difficult to form a stable compound with As(III), often ineffective for As(III), and are effective for cationic heavy metals such as lead and cadmium. Most materials with immobilization effects are ineffective for arsenic, and different iron salts have different arsenic fixation effects. The research on the screening and combination technology system of various materials with long-term immobilization effects on arsenic and heavy metals is still relatively lacking.