A method, system and control method for high-efficiency pressure filtration and leaching of polluted soil

Abstract

The invention discloses a method, system and control method for high-efficiency pressure filtration and leaching polluted soil. The method for repairing heavy metal-contaminated soil comprises the following steps: S1, pulping, acidifying reaction; S2, filtering the above-mentioned fully reacted slurry to obtain soil filter cake and filtrate; S3, pre-washing, so that the filter cake The remaining heavy metals in the capillary pores are replaced and washed out; S4, after the pre-washing, inject the eluent step by step into the washing reaction type diaphragm filter press to perform a multi-stage leaching reaction; S5, after the rinsing reaction, the Stabilize the free heavy metals remaining in the soil filter cake, and at the same time make the tiny heavy metal particles formed during the stabilization process migrate out of the soil, the input pressure is 0.22‑0.35 MPa, and the amount of sulfide leaching water is 50‑80 of the total water content in the soil %; S6, stabilized soil. The invention solves the problem in the prior art that the leaching solution remains in the soil during the leaching process and the index of toxic heavy metals leached from the soil exceeds the standard.

Description

technical field [0001] The invention relates to a method, system and control method for high-efficiency pressure filtration and leaching of polluted soil, belonging to the field of environmental restoration. Background technique [0002] With the rapid development of my country's economy, resource-based minerals have been exploited rapidly, and mining, metallurgy, and chemical companies have launched one after another. Due to relatively backward environmental protection measures and inadequate supervision, the pollution of industrial sites and surrounding soil and groundwater has become increasingly serious. A series of environmental pollution incidents; at the same time, with the acceleration of urbanization and people's increasing sensitivity to environmental pollution, the restoration and reuse of heavy metal-contaminated soil has become one of the most urgent environmental issues. Due to the characteristics of long-term, concealment and irreversibility of heavy metal poll...

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Problems solved by technology

[0007] Aiming at the defects existing in the existing soil leaching repair technology, the present invention aims to provide a method and system for high-efficiency pressure filtration leaching contaminated soil, which can effectively solve the problem of leaching in the prior art leaching process. The residual liquid in the soil leads to the problem that the index of soil leaching toxic heavy metals exceeds the standard and the problem of secondary pollution of the soil by the residual leaching agent in the soil. Further, the present invention can solve the problem of freeing the residual soil with a stabilizer after leaching. When heavy metals are converted into solid phases, tiny particles will enter the liquid phase during leaching toxicity detection, resulting in excessive heavy metal indicators. Furthermore, the present invention can also control the amount of rinsing water from the source to reduce the waste of rinsing agents and recycle the rinsing agents. cost issue

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