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Leaching method for remediating hexavalent chromium contaminated soil

A technology of polluting soil and hexavalent chromium, applied in the field of environmental engineering, can solve the problems of secondary water pollution and large water consumption, and achieve the effect of low cost, easy operation and avoiding secondary pollution

Inactive Publication Date: 2017-04-26
ELION SHOUJIAN ECOLOGICAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the defects of large water consumption and easy to cause secondary water pollution in the existing chemical leaching repair method for hexavalent chromium-contaminated soil, and to provide a method with low water consumption, easy operation, good safety and low cost. A method for remediating hexavalent chromium-contaminated soil with high removal efficiency and no secondary pollution

Method used

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  • Leaching method for remediating hexavalent chromium contaminated soil

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Embodiment 1

[0038] Taking a chromium salt factory in Gansu as an example, the chromium-contaminated soil is subjected to ex-situ leaching treatment. The specific process and restoration effects are as follows:

[0039] According to field testing, the soil pH is about 7.2 to 8.8, and the hexavalent chromium pollution concentration range is 534.70 to 17883.2 mg / kg. For this kind of chromium-containing slag polluted soil with high content of acid-soluble hexavalent chromium, only providing reducing agent and neutralizer can not completely detoxify the soil. Wet grinding must be performed to destroy the physical structure of the slag particles to make the acid soluble state. , The oxidizable state, the reducible state and the residue state are leached by the agent to more fully react with the reducing agent.

[0040] Transport the contaminated soil to the ex-situ treatment area, fill the contaminated soil to the receiving hopper (1), drop from the discharge port to the rod-type vibrating feeder (2...

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Abstract

The invention discloses a leaching method for remediating hexavalent chromium contaminated soil. The method comprises the following steps: (1) slurrying the contaminated soil; (2) fully acidizing materials; (3) adding a reducing agent which is a mixture of calcium polysulfide and ferrite to reduce hexavalent chromium; (4) adding a neutralizing precipitant to precipitate trivalent chromium; and (5) separating solid and liquid, and preparing slurry through supernate. According to the method, a leaching agent and the leaching step are correspondingly simple and convenient to operate, high in safety, low in cost, high in hexavalent chromium recovering efficiency, and hard to cause secondary contamination; meanwhile, wastewater can be recycled, so that the requirement on water for leaching can be met, and as a result, the water resource can be greatly saved, and the secondary contamination caused by drained sewage can be avoided.

Description

Technical field [0001] The invention relates to the field of environmental engineering, in particular to a leaching method for repairing soil contaminated by hexavalent chromium. Background technique [0002] Chromium is a silver-white hard metal, mainly in three forms: metallic chromium, trivalent chromium and hexavalent chromium. All chromium compounds are toxic, of which hexavalent chromium is the most toxic. Hexavalent chromium is a toxic substance that is swallowed / inhaled, and it may cause allergies in contact with the skin; it is more likely to cause hereditary genetic defects. Inhalation may cause cancer and has a lasting risk to the environment. Hexavalent chromium is easily absorbed by the human body. It can invade the human body through digestion, respiratory tract, skin and mucous membranes. The most harmful is the risk of cancer in long-term or short-term contact or inhalation. [0003] At present, domestic and foreign remediation technologies for hexavalent chromiu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/02B01D36/04
CPCB01D36/04B09C1/02
Inventor 李琼董小龙王宝驹甘平张海欧和利钊郑子健黄锦孙
Owner ELION SHOUJIAN ECOLOGICAL TECH CO LTD
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