Slow-release alkali particles for long-acting fixation of soil heavy metals and preparation method thereof

Abstract

The invention relates to the field of soil remediation, and discloses slow-release alkali particles for long-acting fixation of soil heavy metals and a preparation method thereof. The preparation method comprises the following steps: (1) uniformly mixing and grinding sodium sulfide, iron sulfide and colloid, and then spraying water to aggregate, so as to obtain sulfide slow-release particles; and (2) crushing artemisia selengensis, uniformly mixing the crushed artemisia selengensis with fly ash, expanded perlite, kaolin, stone powder, phosphate and cement, adding the sulfide sustained-release particles, spraying water to aggregate, and drying to obtain the sustained-release alkali particles for long-acting fixation of soil heavy metals. The prepared soil heavy metal immobilizing particles have a good slow-release alkaline effect, an alkaline environment is only formed inside and outside the particles during heavy metal stabilization, soil alkalinization is not needed, the effect of long-acting heavy metal immobilizing and stabilizing is achieved, heavy metal is in a stable state for a long time, the defect that soil needs to be alkalized when sulfide is directly adopted for fixing heavy metal in the prior art is effectively overcome, and meanwhile large particles can be removed at any time.

Description

technical field [0001] The invention relates to the field of soil restoration, and discloses a slow-release alkali granule for long-term fixation of heavy metals in soil and a preparation method thereof. Background technique [0002] Soil is an important part of the ecological environment and one of the main resources for human survival. In recent years, with the large-scale discharge of industrial waste residues, the irrigation of farmland with wastewater, and the extensive application of pesticides and phosphate fertilizers, more and more pollutants, including heavy metals, have entered the soil. Inorganic heavy metal pollutants, such as: Cd, Hg, As, Cu, Pb, Cr, Zn, Ni, etc., have poor mobility in the soil, long residence time, cannot be degraded by microorganisms, seriously deteriorate the quality of the soil environment, and can pass through water, plants, etc. And other media into the human body, and ultimately seriously affect human health. Heavy metal pollution is h...

AI Technical Summary

Problems solved by technology

[0007] According to the above, in-situ chemical immobilization repair technology for heavy metal-contaminated soil in the existing scheme, in actual operation, due to the use of chemical fertilizers in farmland, the soil properties are easy to change, which will affect the passivation of heavy metals repaired; for example, direct use of sulfide The heavy metals precipitated by the sediment need to be in a good alkaline environment, and it is difficult to effectively solidify when the soil is acidic

Therefore, the existing heavy metal solidification technology is difficult to solidify for a long time, and there is a greater risk of secondary pollution, which also causes an increase in the cost of heavy metal restoration. The present invention proposes a slow-release alkali particle and a preparation method for long-term fixation of heavy metals in soil. Can effectively solve the above technical problems

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