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Remedying method for removing chrome in contaminated soil of chromium slag site in situ

A technology of chromium-contaminated soil and remediation method is applied in the field of in-situ removal of chromium in contaminated soil from chromium slag sites, and can solve problems such as poor remediation effect of chromium-contaminated soil, achieve significant removal effect, facilitate unified treatment, and reduce unit energy. consumption effect

Active Publication Date: 2015-11-18
CHINESE RES ACAD OF ENVIRONMENTAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The present invention aims at the shortcomings of the prior art that the restoration effect of chromium-contaminated soil in chromium slag sites is poor, and proposes a new electric intensified repair method for in-situ removal of chromium in chromium-contaminated soil in chromium slag sites

Method used

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  • Remedying method for removing chrome in contaminated soil of chromium slag site in situ

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] A restoration method for removing chromium in soil in situ, comprising:

[0032] (1) Get the naturally air-dried chromium-contaminated soil, remove foreign matter therein, use a pulverizer to pulverize, cross a standard sieve with a particle size of 0.50 mm, and set aside;

[0033] (2) Mix the above-mentioned soil to be used with a citric acid solution with a concentration of 0.6-1.2mol / L to make the water content 25%-45%, stir well and then balance for one day;

[0034] (3) Take the above-mentioned balanced soil in the soil sample chamber of the electric restoration device, add 400-650 mesh filter cloths at both ends of the soil sample to prevent the soil from migrating to the cathode and anode chambers during the restoration process, and fill the cathode and anode chambers with electrolyte, The electrolyte is 0.05-0.15mol / L KCl solution;

[0035] (4) Insert the graphite electrode into the middle of the cathode and anode chamber, insert it to the bottom, connect the p...

Embodiment 2

[0040]In order to verify the effect of the remediation method in Example 1 on the removal of chromium in the actual chromium slag contaminated soil, the following experiments were carried out.

[0041] (1) Get the chromium-contaminated soil after natural air-drying (wherein, the total chromium content in the soil is 6612~16898mg / kg, the hexavalent chromium content is 944~2654mg / kg, pH=8.6~10.3), remove the impurities After pulverizing with a pulverizer, pass through a 0.50mm sieve for use;

[0042] (2) Mix 5.6Kg of the above-mentioned soil to be used with 2.4L of citric acid solution of 0.9mol / L, stir evenly with a stainless steel shovel, and let stand for one day;

[0043] (3) Get 7Kg of above-mentioned equalized soil in the soil sample room of the electric repair device, (the structure of the electric repair device is shown in embodiment 3), wherein, the soil sample room size is 30cm * 20cm * 10cm, the size of the negative and positive electrode chambers at both ends 10cm×2...

Embodiment 3

[0049] Embodiment 3 electric restoration device

[0050] The electric restoration device that the present invention adopts, as figure 1 As shown, it includes: soil sample chamber (1), anode chamber (2), cathode chamber (3), DC power supply (4), ammeter (5), filter screen (6), pH adjustment system (7), electrode ( 8), overflow hole (9), acid solution tank (10), alkali solution tank (11), collection tank (12).

[0051] Among them, the soil sample chamber (1) is used to fill the soil for testing, and its size ratio is length: width: height = 3:2:1. The anode chamber (2) is adjacent to the left and right sides of the soil sample chamber (1). 1. The dimensions of the cathode chamber (3), the anode chamber (2), and the cathode chamber (3) are length: width: height = 1:2:1. A strainer is pasted on the inner wall adjacent to the anode and cathode chambers of the soil sample chamber, an electrode 8 is arranged in the middle of the anode chamber and the cathode chamber, and the two el...

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Abstract

The invention discloses a remedying method for removing chrome in contaminated soil of a chromium slag site in situ. The method comprises the following steps of: (1) smashing the air-dried chromium-contaminated soil of the chromium slag site, and sieving the smashed soil; (2) mixing the soil sieved in the step (1) and a citric acid solution to ensure that the moisture content of the soil reaches a set value, carrying out uniform stirring and then carrying out balancing for one day; (3) putting the soil balanced in the step (2) in a soil sample chamber of an electrokinetic remediation device, wherein the two ends of the soil sample chamber of the electrokinetic remediation device are respectively a cathode chamber and an anode chamber; and (4) adding an electrolyte to the cathode chamber and the anode chamber, respectively inserting graphite electrodes in the cathode chamber and the anode chamber, and connecting a power source to ensure that electric currents pass through the soil chamber to carry out electrokinetic remediation, wherein the electrolyte is a KCI solution. For the high-chromium-content alkaline contaminated soil of the chromium slag site, the remedying method is simple in technology, higher in removal efficiency of chrome in comparison with a common electrokinetic remediation method, low in unit energy consumption and lowered in cost, and can effectively reduce the bioavailability of residual chromium in the soil.

Description

technical field [0001] The invention belongs to the technical field of soil pollution remediation, and in particular relates to a remediation method for in-situ removal of chromium in soil contaminated by chromium slag sites. Background technique [0002] Chromium slag is a highly toxic solid waste, the main source of which is the discharge from chromium salt production plants and ferrochrome alloy plants. In my country, more than 20 cities including Shanghai, Qingdao, Changsha, Suzhou, Wuhan, and Shenyang have nearly 6 million tons of leftover chromium slag. Chromium slag contains a large amount of water-soluble hexavalent chromium. Hexavalent chromium has strong "three-to-one" properties. At the same time, chromium slag also has a high content of calcium chromate, which has strong carcinogenicity. [0003] At present, a large amount of chromium slag is directly piled up in the open air without any harmless treatment after collection. In this stacking environment, the chr...

Claims

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Application Information

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IPC IPC(8): B09C1/08
Inventor 孟凡生王业耀薛浩
Owner CHINESE RES ACAD OF ENVIRONMENTAL SCI
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