Immobilizing and insolubilizing material for heavy metal polluted soil based on magnesium oxide

Abstract

The invention discloses an immobilizing and insolubilizing material for heavy metal polluted soil based on magnesium oxide. The immobilizing and insolubilizing material is composed of a magnesium oxide main agent and a heavy metal immobilizing and insolubilizing aid. The magnesium oxide is obtained by performing high-temperature firing on lightly fired dolomite, the addition amount is 1-30% of polluted soil, the magnesium oxide has a favorable heavy metal insolubilizing effect and a high heavy metal insolubilizing speed because of the low alkalinity, and the immobilized product is high in strength and is suitable for utilization in buildings and the like; and the heavy metal immobilizing and insolubilizing aid is composed of an immobilizing accelerator, a reinforcing agent and an organic coagulant, the insolubilizing strength can be improved, the insolubilizing speed can be increased, the heavy metal insolubilized product is stable for a long time, and the addition amount of the heavy metal immobilizing and insolubilizing aid is 0.1-10% of the polluted soil. The material disclosed by the invention can quickly, efficiently and persistently immobilize and insolubilize heavy metal ions (mainly water-soluble and exchangeable) in the soil, thereby reducing the toxicity of the heavy metal ions to the ecological environment. The material has the advantage of favorable persistence, and especially has a favorable treatment effect on high-concentration lead (Pb), mercury (Hg), cadmium (Cd), chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag), metalloid arsenic (As) and the like.

Description

technical field [0001] The invention relates to a treatment material for heavy metal polluted soil, in particular to a solidified and insoluble material for heavy metal polluted soil based on magnesium oxide. Background technique [0002] In recent years, when urban factories are relocated and the original site is used for the construction of densely populated apartments or commercial blocks, the soil pollution has attracted much attention due to the long-term accumulation of a large amount of harmful substances in the soil. Excavation, foreign soil replacement and original Bit manipulation techniques are commonly used methods. Excavation and foreign soil replacement are rarely used because of the large amount of engineering and high input costs; in-situ treatment needs to inject chemicals into the polluted soil, which will cause the strength of the site to decrease. Some people have proposed methods such as directly mixing ordinary cement and blast furnace cement into the s...

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Problems solved by technology

Excavation and foreign soil replacement are rarely used because of the large amount of engineering and high input costs; in-situ treatment needs to inject chemicals into the polluted soil, which will cause the strength of the site to decrease. Some people have proposed methods such as directly mixing ordinary cement and blast furnace cement into the soil Increase the intensity of soil treatment, but this method will cause the soil to become strongly alkaline, resulting in a decline in the effect of soil treatment

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