Ex-situ sorting, cleaning and repairing device for chromium-polluted soil and cleaning and repairing technology using ex-situ sorting, cleaning and repairing device

Abstract

The invention relates to an ex-situ sorting, cleaning and repairing device for chromium-polluted soil and a cleaning and repairing technology using the ex-situ sorting, cleaning and repairing device. The ex-situ sorting, cleaning and repairing device comprises a raw material treatment unit, a first-level oversize particle treatment unit, a first-level undersize liquid treatment unit, a second-level undersize liquid treatment unit, a waste liquid collecting unit, a waste liquid treatment unit, a cleaning liquid adding unit and a chemical adding unit. The cleaning and repairing technology for conducting ex-situ sorting and cleaning on the chromium-polluted soil through the device comprises the steps of pulping, soil particle classification, cleaning of soil particles different in level and waste liquid treatment. The whole technology process is simple, equipment is easy to machine, the publicly known equipment can be adopted, the cost is low, the occupied space is small, continuous operation can be conducted, and energy consumption is low. The removal rate for hexavalent chromium in the soil can reach 95% or above, the residue concentration of the hexavalent chromium is lower than 50 mg / kg, and influences of the chromium on the soil, underground water and the surrounding environment are removed.

Description

technical field [0001] The invention belongs to the technical field of soil pollution control and repair, and in particular relates to a device for cleaning and repairing chromium-contaminated soil in situ sorting and a cleaning and repair process thereof. Background technique [0002] Since the country issued the "Comprehensive Treatment Plan for Chromium Slag Pollution" in 2005, my country has completed the harmless disposal of all historical stockpiled chromium residues, but the remaining chromium-contaminated soil and groundwater have not been treated. Because chromium (Ⅵ), the main pollutant in chromium-contaminated soil, is soluble in water and highly toxic, it poses a great threat to the soil, rivers and polluted groundwater around the long-term storage site. The object of treatment, my country is in urgent need of key technologies for remediating the soil of chromium slag-contaminated sites. [0003] According to the characteristics of chromium-contaminated sites and...

AI Technical Summary

Problems solved by technology

However, this technology mainly has the following shortcomings: ①The volume increase ratio is large, and the volume of the mixture formed after the disposal of contaminated soil increases; ②The solidified / stabilized mixture needs to be disposed of safely, and the mixture needs long-term monitoring and monitoring in the later stage. Tracking; ③ organic pollutants and moisture content, chemical adsorption and aging process can all affect its effect, and this technology cannot fundamentally remove heavy metals

Among them, Wang Xingrun et al. (patent application number: 200910241688.1) adopted a two-stage countercurrent washing plus chemical stabilization combination process. Although water is used as the leaching agent, the treatment cost and risk are greatly reduced, but the soil after treatment will continue to turn yellow. phenomenon, which shows that the disposal of hexavalent chromium in soil is not complete, and secondary or multiple disposals are required; Zhai Yonghong et al. (patent application number: 201510494866.7) used an alkaline aqueous solution of sodium edetate as There are no specific steps and methods and solid-liquid separation measures and equipment, which cannot meet the requirements of project implementation; Zheng Hao et al. (patent application number: 201520566384.3) adopt two-stage cleaning, the method steps are specific, and the equipment and process can be used. Strong operability, but this method is only suitable for sandy soil, the application range is too narrow, and this technology only separates sand particles with a particle size greater than 75 μm, and the volume reduction of contaminated soil is limited

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