Curing-stabilization chemical for restoring arsenic-polluted soil and preparation method and application of curing-stabilization chemical

Abstract

The invention provides a curing-stabilization chemical for restoring arsenic-polluted soil. The curing-stabilization chemical comprises, by weight percentage, 10-15% of an oxidizing agent, 20-40% of a curing agent, 22-45% of a stabilizing agent, 10-35% of additives and 3-8% of a synergist. By means of the curing-stabilization chemical, the existing form of arsenic is changed, the arsenic is fixed into the soil through the oxidoreduction effect, the precipitation effect and the adsorption effect, and chemical properties of the arsenic are stabilized; mobility and bio-availability of the arsenic are lowered; and through five types of synergistic interaction effects, the restoration effect is good. The arsenic-polluted soil is treated and restored with the chemical; the total arsenic concentration of arsenic slag sample leachate is 294 mg / L, and the pH value is 7.5; after treatment, the total arsenic concentration of the leachate is 2.3 mg / L, the pH value is 5.0, and the arsenic fixing rate is as high as 99.86%; and meanwhile, the restoration standard, namely 2.5 mg / L, specified in 'Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes' is reached.

Description

technical field [0001] The invention belongs to the technical field of soil remediation, and in particular relates to a curing-stabilizing agent for arsenic-contaminated soil remediation, a preparation method and application thereof. Background technique [0002] Soil arsenic pollution is ubiquitous in the world. For example, in natural minerals, common arsenic-containing minerals are: arsenopyrite / arsenopyrite (FeAsS), orthosiderite arsenite (FeAs 2 ), realgar (As 2 S 3 ), orpiment (As 2 S 3 ), arsenite (Cu 3 AsS 4 ), cobalt arsenite (CoAsS), nickel arsenite (NiAsS), etc. These arsenic-containing minerals are often associated with metal sulfide ores, and a large amount of arsenic remains in the soil during the mining and processing of minerals. Most antimony ores in my country contain arsenic, and the arsenic-removing scum produced when adding soda ash to remove arsenic during the antimony smelting and refining process and the secondary arsenic-alkali slag produced b...

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Problems solved by technology

However, although the above scheme removes heavy metals in the soil, it increases the content of heavy metals in the atmosphere, causing air pollution, and does not solve the fundamental problem

[0004] The soil amendment method is currently a relatively common method of soil restoration, but commercial restoration agents imported from abroad are usually expensive and not suitable for large-scale promotion; while domestic soil restoration agent products are few, and the restoration effect is remarkable. For example, the public No. CN106190163 discloses a remediation agent for arsenic-contaminated soil, the fixation rate of soil arsenic after contaminated soil treatment reaches 75% to 86.6%. It is unknown whether the remediation ability of arsenic-contaminated soil is significant

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