KR101247224B1 - Method for remediating soil contaminated with zinc using solvent extraction and thereof system - Google Patents

Abstract

PURPOSE: A purification method of zinc polluted soil using a solvent extraction and a system thereof are provided to improve the zinc removal efficiency out of the zinc polluted soil and to prevent the second environmental contamination as an extraction agent is able to be recycled. CONSTITUTION: A purification method of zinc polluted soil comprises a step of mixing an extracting solution in which D2EHPA(Di-2-ethylhexylphosphoric acid) is dissolved in water, to zinc polluted soil. The zinc concentration of the zinc polluted soil is 1000-5000 mg/kg. The mixing ratio of the extracting solution to the zinc polluted soil is a weight ratio of 1:1. In case the zinc concentration in the zinc polluted soil is less than 1500 mg/kg, the extracting solution and the zinc polluted soil are reacted for 0.5-0.6 hours in a first stage extractor to extract zinc from the polluted soil and separate purified soil simultaneously. In case the zinc concentration in the zinc polluted soil is more than 1500 mg/kg and under 4000 mg/kg, the extracting solution is supplied to a second stage extractor and reacted with the polluted soil in which zinc is firstly extracted in the first stage extractor, for 0.5-0.6 hours to separate purified soil by re-extracting zinc from the polluted soil and to send the extracting solution used in the second stage extractor to the first stage extractor again in order to be recycled. In case the zinc concentration in the zinc polluted soil is more than 4000 mg/kg and under 5000 mg/kg, the extracting solution is supplied to a third stage extractor and reacted with the polluted soil in which zinc is firstly and secondly extracted in the first and second stage extractors, for 0.5-0.6 hours to separate purified soil by re-extracting zinc from the polluted soil and to send the extracting solution used in the third stage extractor to the second and first stage extractors consecutively in order to be recycled. [Reference numerals] (AA) Solvent after extracting contaminated soil; (BB) Purified soil; (CC) Supplying solvent

Description

METHODS FOR REMEDIATING SOIL CONTAMINATED WITH ZINC USING SOLVENT EXTRACTION AND THEREOF SYSTEM.}

The present invention relates to a method for purifying soil contaminated with zinc using a solvent extraction method and a system thereof, and more particularly, to a system for purifying soil contaminated with zinc using an extractant having excellent zinc extraction efficiency.

Recently, there are frequent cases of soil contamination in areas such as oil tankers, storage facilities, organic solvent storage facilities in industrial complexes, military units, and waste and abandoned mines, but effective treatment technologies have not been secured yet.

Soil and groundwater contamination is less directly noticeable than other environmentally contaminated areas, and since such contamination is very slow, the discovery of contamination is often delayed, and the range of damage from pollution is extensive. Placenta is the case of contamination.

In addition, in the severely polluted state, a large purification cost is required for purification and a considerable time is required for the purification, and thus, there is an urgent need for strengthening environmental standards and developing practical, high-efficiency, low-cost purification technologies that meet industrial requirements. .

Recently, the development of technology for the treatment of heavy metal-contaminated soil is urgently needed than the euro-contaminated soil, but to date, there are absolutely no cases of technology development and heavy metal treatment in Korea.

In particular, in Korea, the use of solidification / stabilization technology, which is the most widely used treatment technology for heavy metals in the Soil Groundwater Environment Conservation Act, is not legally mandated. Most of it uses soil washing and coin techniques. To treat heavy metals.

Soil washing is a technique that uses a cleaning agent such as hydrochloric acid or sulfuric acid to reduce the surface tension of harmful organic pollutants bound to soil particles or to change heavy metals into liquid phase. This soil washing method aims to elute the pollutants that are not chemically strongly bound with the cleaning agent, and has the advantage of quickly processing hazardous chemicals or heavy metals that are difficult to biodegrade. Depending on the type of detergent, a wide range of inorganic contaminants can be removed, but when contaminants are present in combination, it is difficult to select an appropriate detergent, and there is a disadvantage that it is difficult to apply to contaminants that are chemically strongly bound.

On the other hand, the coin technique is a method of treating contaminated soils in saturated areas by promoting the movement speed of ionic contaminants in the saturated soil with low permeability coefficient by the electric field of the anode and cathode.

This method is an underground soil treatment technology that removes contaminants from soils, clays, sludges and dredged soils with low permeability coefficients by connecting electrodes to the contaminated area and flowing current.

In general, in the case of soil with a low permeability coefficient mixed with a large amount of fine soil, it is not easy to apply the soil pollution treatment technology, the coin method has the advantage that can obtain a high treatment efficiency even in a soil with a low permeability coefficient.

However, the coin technique requires a lot of electricity and requires a lot of operating costs, and can produce unnecessary by-products by oxidation / reduction reactions. When the moisture content in the soil is less than 10%, the purification efficiency is drastically reduced to supply water again. It has a disadvantage to be given.

In addition, in the case of soil washing, there is a disadvantage in that it can be treated depending on the nature of the soil and the form of heavy metals, as well as a secondary environmental pollution caused by washing water and sludge. In addition, there is a disadvantage that the treatment is possible only when the heavy metal is present in the ionic state, and there is a problem in that the heavy metal existing in various forms cannot be completely processed.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as adhering to the prior art already known to those skilled in the art.

Korean Patent Publication No. 10-2004-0058505 (2004.07.05.)

In order to solve the above problems, the present invention selectively extracts zinc present in the soil by using water and extractant in soil contaminated with zinc to remove zinc in the soil, and recycles the used extractant. An object of the present invention is to provide a method for purifying contaminated zinc soil using a solvent extraction method and a system thereof.

Zinc contaminated soil purification method according to the present invention for achieving this object, to clean the soil contaminated with zinc by mixing the extract liquid dissolved in water with D-2-EHPA (Di-2-ethylhexylphosphoric acid) extractant in the soil contaminated with zinc However, the zinc concentration of the soil contaminated with zinc is 1000 to 5000mg / kg, and when the extract is used by dissolving D-2-EHPA (Di-2-ethylhexylphosphoric acid) in water, the extract is used for the soil contaminated with zinc. When the zinc concentration of the soil contaminated with zinc is less than 1500 mg / kg, the extract is reacted with the extract-contaminated soil for 0.5 to 0.6 hours in a single-stage extractor. At the same time as the extraction, the purified soil is separated, and when the zinc concentration of the soil contaminated with zinc is 1500 mg / kg or more and less than 4000 mg / kg, the extract is supplied with a two-stage extractor. The first stage extractor reacts with the contaminated soil from which zinc was first extracted for 0.5 to 0.6 hours to re-extract zinc from the contaminated soil to separate the purified soil, and simultaneously extracts the extract used in the second stage extractor. If the zinc concentration of the soil contaminated with zinc is 4000mg / kg or more and 5000mg / kg or less, the extractant is supplied to the three-stage extractor, and the first and second stage extractors are used in the first and second stage extractors. Reacting zinc with contaminated soil extracted with zinc for 0.5 to 0.6 hours to separate the purified soil by re-extracting zinc from the contaminated soil and simultaneously extracting the extract used in the three-stage extractor to the two-stage extractor and the first-stage extractor. It is characterized by recycling the extract by sending continuously.

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Zinc contaminated soil purification system according to the present invention for achieving this object, the first stage extractor, the second stage extractor and the three stage extractor to sequentially move according to the degree of contamination of the contaminated soil with zinc concentration of 1000 ~ 5000mg / kg Including extractor containing, D2EHPA (Di-2-ethylhexylphosphoric acid) dissolved in water extracts are sequentially supplied to the three-stage extractor, two-stage extractor and one-stage extractor, but with a 1: 1 ratio of zinc contaminated soil and its weight ratio When the zinc concentration of the soil contaminated with zinc is less than 1500 mg / kg, the extract and the soil contaminated with zinc are reacted in the first stage extractor for 0.5 to 0.6 hours to separate the purified soil and contaminated with zinc. When the zinc concentration in the soil is 1500 mg / kg or more and less than 4000 mg / kg, the purified soil is separated by reacting the extract and the zinc-contaminated soil in the first and second stage extractors for 0.5 to 0.6 hours, respectively. If the zinc concentration of the soil contaminated with zinc is 4000 mg / kg or more and 5000 mg / kg or less, the extract and the zinc-contaminated soil are reacted for 0.5 to 0.6 hours in the single-stage extractor, the two-stage extractor, and the three-stage extractor, respectively. Separation of the purified soil, and through the three-stage extractor, two-stage extractor and the first-stage extractor continuously mixed with the discharged solvent and the stripping liquid to selectively extract the heavy metal in the solvent, the purified solvent to the three-stage extractor And a heavy metal concentration tank for receiving and storing the heavy metal extracted from the stripping tank and re-supplying the furnace.

The sensor unit for measuring the zinc concentration of the extract liquid discharged from the first stage extractor, the second stage extractor and the three stage extractor in real time, and receiving information on the real-time concentration of the extract from the sensor unit can visually recognize the information. Monitor to output; And a control unit for receiving the increase and decrease signal from the monitor to increase and decrease the flow rate of the solvent to the three-stage extractor to adjust the supply flow rate of the solvent in accordance with the increase and decrease of the zinc content of the extract.

The present invention has the advantage that the secondary environmental pollution can be prevented because of the improvement of the zinc removal efficiency of the zinc-contaminated soil due to the above-described technical configuration, as well as recycling the extractant.

1 is a conceptual diagram for explaining the multi-stage countercurrent extraction method used in the present invention,
2 is a view showing a zinc contaminated soil purification system using the solvent extraction method of the present invention.

Hereinafter, a zinc contaminated soil purification method and a system using a solvent extraction method according to a preferred embodiment of the present invention with reference to the accompanying drawings.

Zinc contaminated soil purification method using the solvent extraction method of the present invention, the soil contaminated with zinc, D2EHPA (Di-2-ethylhexylphosphoric acid), Versatic acid-10, TBP (Tri-butyl-phosphate), TOP (Tri-octyl) It is characterized in that to extract zinc from the soil contaminated with zinc by mixing the extract solution dissolved in water any one extractant selected from -phosphate).

The present inventors are extractant, D2EHPA (Di-2-ethylhexylphosphoric acid) and Versatic acid-10, TBP (Tri-butyl-phosphate), TBP (Tri-butyl-phosphate) and TOP (Tri-octyl) -phosphate), the zinc extraction efficiency analysis experiment.

Acidic extractants are acids such as alkylphosphoric acid and carboxylic acid, which are combined and extracted by exchanging cations with heavy metals present as cations. For example, alkylphosphoric acid may be used for heavy metals such as copper, cobalt, nickel, and the like which exist as divalent ions in an aqueous solution.

Cu ^{2 +} + 2R ₂ HPO _4- > Cu (R ₂ PO ₄ ) ₂ + 2H ⁺

In addition, a neutral extractant means an electrically neutral extractant, and such extractants include ethers, alcohols and neutral phosphoric acid esters having an oxygen atom together with a pair of electrons.

Neutral extractants are mainly used for acid extraction, such as hydrofluoric acid, or for extraction of heavy metals in the form of acid-bound forms, for example uranium extraction from UO ₂ (NO ₃ ) ₂ solution by TBP (Tributyl phosphate). Can be.

_{^{UO 2 2 + + 2NO 3 -}} + 2 [TBP] -> [UO 2 (NO 3) 2 (TBP) 2]

As the extraction method of the present invention, a multistage countercurrent extraction method was used, and a total of three steps were extracted.

The multi-stage countercurrent extraction method is for continuous operation of solvent extraction, and has an advantage of improving the recovery rate and separability of the target component compared to the batch type method.

The multistage countercurrent extraction process is a process of extracting the target components into the liquid phase by contacting two liquid phases which are physicochemically different in the countercurrent direction. The multistage countercurrent extraction method of the present invention was treated by the multistage countercurrent extraction method by contacting the soil of 2 mm or less in the countercurrent direction with the solvent.

The conceptual diagram of the multistage countercurrent extraction method of the present invention is shown in FIG.

As shown in FIG. 1, the supplied solvent is introduced into reactor n and discharged through reactor 1. The discharged solvent is recycled to reactor n through a solvent regeneration facility. Soil less than 2mm is supplied to reactor 1 and discharged through reactor n while being mixed with the supplied solvent. The discharged soil is separated through the filter press and separated into solids and transferred to the discharge facility. Through this method, the continuous process by multi-stage extraction is possible, and the treatment efficiency by the extractant is maximized.

As extraction conditions, the weight ratio of the soil contaminated with zinc to the soil contaminated with zinc was adjusted to 1: 1, and mixed and stirred at a stirring speed of 500 rpm, but the reaction time was 30 for each step. Adjusted to minutes.

After the reaction, the liquid phase and the soil were sampled, and the concentrations of zinc after pretreatment by the respective water quality and soil process test methods were analyzed using an inductively coupled plasma emission spectrometer. The results are shown in Table 1 below.

As shown in Table 1, the zinc concentration of the soil contaminated with zinc before the treatment was 2587.4 mg / kg. When extracted using D2EHPA, the zinc concentration of the soil after the treatment was 17.4 mg / kg, indicating a very high extraction efficiency. It was.

In addition, when extracted using Versatic acid-10, TBP, TOP showed 382.7 mg / kg, 482.7 mg / kg, 397.2 mg / kg, respectively.

In general, in relation to heavy metal contaminated soils, the soil environmental conservation method provides the heavy metal standards as shown in Table 2 below.

Pollution Concern Standard 1 includes, for example, fields, answers, orchards, ranch land, school land, fish farms, and parks, and Contamination Concern 2 includes forests, salt fields, rivers, etc. Areas include factory sites, parking lots, etc., and the allowance for heavy metals is raised from one region to three regions.

heavy metal As CD Cu Pb Zn Pollution concern standard 1 area 25 4 150 200 300 Pollution Concern Standard 2 50 10 500 400 600 Pollution Concern 3 Areas 200 60 2000 700 2000

As shown in Table 1 and Table 2, the D2EHPA satisfies the 300 mg / kg condition for pollution 1 area, while Versatic acid-10, TBP, and TOP exceeded the 1 area for pollution concern. It was found that the standard value of 600 mg / kg was satisfied.

In particular, the zinc removal efficiency of D2EHPA was about 99.3%, showing the highest zinc removal efficiency among the extractants.

According to the zinc contaminated soil purification method using the solvent extraction method of the present invention, the zinc removal effect can be obtained as described above, the present inventors, in particular, even in the case of using D2EHPA, in order to satisfy the contamination area 1 standard value The experiment was performed to adjust the results, the results are shown in Table 3 below.

As shown in Table 3, in order to set the extraction stage to satisfy the pollution concern 1 zone standard value, the zinc concentration after treatment according to the extraction stage by the contaminated soil zinc concentration was measured.

Extraction was performed using a mixer setler apparatus to improve recovery and separation, and was performed by a multistage countercurrent extraction method.

10kg / hr of contaminated soil, and the ratio of extract and soil were 1: 1 as weight ratio, and the reaction time of each stage was performed for 30 minutes each.

The concentration range of contaminated soil was adjusted to 1000mg / kg ~ 5000mg / kg, with a maximum concentration of 5000mg / kg, which is 2.5 times the 2000mg / kg, which is the standard of three soil pollution concerns.

The dotted line in Table 3 indicates the zinc concentration of 300 mg / kg, which is the standard for soil contamination 1 region. As a result of observing the number of extracted extracts for each concentration satisfying this criterion, when the zinc concentration is less than 1500 mg / kg, One step treatment of the zinc-contaminated soil was found to satisfy the regional standards for concern about soil contamination. First reaction,

When the zinc concentration of zinc-contaminated soil is more than 1500mg / kg and less than 4000mg / kg, two-stage treatment is required. If the zinc concentration of zinc-contaminated soil is more than 4000mg / kg and 5000mg / kg, three-stage treatment meets the criteria for one area of concern about soil pollution. I could see.

On the other hand, the inventor performed a separate experiment to determine the zinc removal rate according to the extract and the soil ratio.

D2EHPA was selected as the extract to set the optimum condition of the extract and soil ratio. The polluted soil was 10kg / hr, the reaction time of each stage was 30 minutes, and the extraction stage was set to 3 stages.

When the initial zinc concentration is 2587.4 mg / kg, the concentration of soil after treatment and its treatment efficiency are shown in Table 4 below.

As shown in Table 4, the extraction efficiency increased as the weight ratio of the extract to soil increased. In particular, it was confirmed that the zinc removal efficiency reached 98.87% when the weight ratio of the soil to the extract was 1: 1. At higher ratios, the treatment efficiency satisfies a certain level. When D2EHPA was used, the optimum solid ratio was found to be 1: 1.

The inventors have tested the zinc removal efficiency over the reaction time.

In order to measure the zinc removal efficiency according to the reaction time, D2EHPA was applied as the extract with the extract and soil ratio set to 1: 1, and the reaction residence of each stage at 10 kg / hr of contaminated soil in total extraction stage. Treatment efficiency was measured while adjusting the time in the range of 5 to 30 minutes, and the results are shown in Table 5 below.

As shown in Table 5, the zinc removal amount was low at 881.5 mg / kg soil at 5 minutes of reaction time, but the zinc throughput increased as the reaction time increased.

In 30 minutes of reaction time, the amount of zinc removed was 3297.4mg / kg of soil, and there was no significant change in the reaction time.

Therefore, the reaction time to maximize the zinc removal efficiency was found to be 30 minutes based on each stage.

The zinc treatment efficiencies of the experimental example and the comparative example according to the zinc contaminated soil purification method using the solvent extraction method of the present invention are shown in Table 6 below.

Experimental Examples 1 to 3 show experimental examples according to the present invention, Comparative Examples 1 to 5, Comparative Example 1 is a case of experiments with different extraction ratios, Comparative Example 2 was tested by varying the extraction time Comparative Example 3 is HCL, Comparative Example 4 is EDTA, Comparative Example 5 uses Texapon N-40 as the extractant.

Extractant Extraction cost
(Extract: soil w / w) Extraction time
(hr) Zinc concentration before treatment
(mg / kg) Zinc concentration after treatment
(mg / kg) Processing efficiency
(%) Comparative Example 1 D2EPHA 1: 0.8 0.5 2587.4 151.0 94.2 Comparative Example 2 D2EPHA 1: 1 0.4 3297.4 161.2 95.1 Experimental Example 1 D2EPHA 1: 1 0.5 2587.4 29.0 98.9 Experimental Example 2 D2EPHA 1: 1 0.6 3297.4 15.6 99.5 Experimental Example 3 D2EPHA 1: 1 0.5 627 5.6 99.1 Comparative Example 3 ¹⁾ HCl 5: 1 One 273 180.2 34 Comparative Example 4 ²⁾ EDTA 1: 1 2 800 496 38 Comparative Example 5 ³⁾ Texapon N-40 3.3: 1 23 261 34.9 86.6

※ 1) Excerpts from "A study on the feasibility study of zinc-contaminated railroad soils using detergent" Vol.14 (1), p78 ~ 82, 2009,

※ 2) Excerpt from Journal of Hazardous materials, Vol. 215-216, p32 ~ 39, 2012, "Pilot-scale washing of metal contaminated garden soil using EDTA."

※ 3) Physics and chemistry of the Earth, Vol. 37-39, p30-36, 2012, "Removal of As, Cd, Cu, Ni, Pb and Zn fro, a highly contaminated industrial soil using surfactant enhanced soil washing."

As shown in Table 6, it was found that the residual zinc concentration was less than 1/5 when the extraction ratio was set to 1: 1 compared to the case where the extraction ratio was set to 1: 0.8.

In addition, when the reaction time was set to 0.6 hours in Experimental Example 2 than when the reaction time was set to 0.4 hours, it was found that the residual zinc concentration decreased by about 10 times.

With reference to Figure 2, it will be described a zinc contaminated soil purification system using the solvent extraction method of the present invention.

Zinc contaminated soil purification system using the solvent extraction method of the present invention includes an extractor, stripping tank, heavy metal concentration tank and filter press.

The extractor includes a single stage extractor, a two stage extractor, and a three stage extractor, and the zinc contaminated soil passes through the first stage extractor, the two stage extractor and the three stage extractor according to its pollution degree. On the other hand, the extract flows in the reverse direction with the zinc contaminated soil, and passes continuously through the three-stage extractor, the two-stage extractor, and the first-stage extractor.

For example, when the zinc contamination is severe, the zinc-contaminated soil is first purified by the circulating extract, and the zinc-contaminated soil that is purified first is purified by the second-stage extractor and the third-stage extractor. At this time, the extract is recycled while flowing backward with the zinc-contaminated soil. The purest extract supplied to the three-stage extractor is used to finally clean up the first and second purified zinc contaminated soils, and then the two-stage extractor and the first-stage extractor. It is supplied to and recycled.

One-stage extractor is supplied with 1: 1 contaminated soil with zinc concentration of 1000 to 5000 mg / kg and extracts dissolved in water with D2EHPA (Di-2-ethylhexylphosphoric acid) in a weight ratio of 1: 1. If the concentration is less than 1500 mg / kg, it functions to react the extract and the soil contaminated with zinc for 0.5 to 0.6 hours. The soil purified by reaction in the first stage extractor is discharged separately from the extract.

If the zinc concentration of the soil contaminated with zinc is 1500 mg / kg or more and less than 4000 mg / kg, the two-stage reaction occurs in the single stage extractor and the two stage extractor.

That is, the zinc-contaminated soil is first purified in the first stage extractor and secondly purified in the second stage extractor. The extract is first supplied to the second stage extractor, and is supplied to the first stage extractor for recycling. At this time, the first stage extractor and the second stage extractor are reacted for 0.5 to 0.6 hours.

When the zinc concentration of the soil contaminated with zinc is 4000 mg / kg or more and 5000 mg / kg or less, three-stage reactions occur in the single-stage extractor, the two-stage extractor, and the three-stage extractor.

That is, the zinc-contaminated soil is first purified in the first stage extractor, secondly purified in the second stage extractor, and thirdly purified in the third stage extractor. The extract is first supplied to the third stage extractor, and used in the second stage extractor and It is continuously supplied to a single-stage extractor and recycled. In this case, the first stage extractor, the second stage extractor, and the third stage extractor are reacted for 0.5 to 0.6 hours.

The stripping tank functions to selectively extract heavy metals in the solvent by mixing a stripping solution such as ammonium hydroxide with a solvent and water after extraction. The purified solvent is supplied to a three-stage extractor and continuously fed to a two-stage extractor and a single-stage extractor. And the stripping liquid is sent to a heavy metal concentrator.

On the other hand, zinc contaminated soil purification system using the solvent extraction method of the present invention, the sensor unit for measuring the zinc concentration of the extract liquid discharged from the first stage extractor, the second stage extractor and the three stage extractor in real time, and the real time of the extract liquid from the sensor unit Monitor that receives information about the concentration and outputs the information visually, and receives the increase and decrease signal from the monitor so that the flow rate of the solvent can be adjusted according to the increase or decrease of zinc content of the extract, It is preferable to include the control part which increases or decreases a flow volume.

Therefore, by detecting the zinc content of the extract in real time, the solvent supply amount can be increased before the concentration of the heavy metal content of the extract reaches the saturation value, thereby improving the heavy metal treatment efficiency.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims It will be apparent to those of ordinary skill in the art.

Claims (4)

In order to clean the soil contaminated with zinc, mix the extract dissolved in D2EHPA (Di-2-ethylhexylphosphoric acid) extract in water.
Sodium contaminated with zinc has a zinc concentration of 1000 to 5000 mg / kg,
When D2EHPA (Di-2-ethylhexylphosphoric acid) is used as the extract in water, the extract is mixed in a weight ratio of 1: 1 with respect to the soil contaminated with zinc.
If the zinc concentration of the soil contaminated with zinc is less than 1500 mg / kg, the extractor reacts with the soil contaminated with zinc for 0.5 to 0.6 hours in a single stage extractor to extract zinc from the contaminated soil and to separate the purified soil. Betting,
When the zinc concentration of the soil contaminated with zinc is 1500 mg / kg or more and less than 4000 mg / kg, the extract is supplied to the two-stage extractor and reacted with the contaminated soil in which the zinc is first extracted from the first-stage extractor for 0.5 to 0.6 hours. Re-extract zinc from the contaminated soil to separate the purified soil, and at the same time send the extract used in the two-stage extractor to the first-stage extractor to recycle the extract,
When the zinc concentration of the soil contaminated with zinc is 4000 mg / kg or more and 5000 mg / kg or less, the extractive liquid is supplied to the three-stage extractor, and the contaminated soil in which zinc is extracted first and second in the first and second stage extractors. And 0.5 to 0.6 hours to re-extract zinc from the contaminated soil to separate the purified soil, and at the same time, the extract used in the three-stage extractor is continuously sent to the two-stage extractor and the first-stage extractor to recycle the extract. Characterized in that the zinc contaminated soil purification method using a solvent extraction method.
delete Including extractor including one-stage extractor, two-stage extractor and three-stage extractor, which sequentially move according to the degree of contamination of contaminated soil with zinc concentration of 1000 to 5000mg / kg, and contains D2EHPA (Di-2-ethylhexylphosphoric acid). Extracts dissolved in water are sequentially supplied to the three-stage extractor, the two-stage extractor, and the first-stage extractor, but are supplied at a ratio of 1: 1 by weight of zinc-contaminated soil and its weight, and when the zinc concentration of the soil contaminated with zinc is less than 1500 mg / kg. In order to separate the purified soil by reacting the soil contaminated with the extract with zinc in the first stage extractor for 0.5 to 0.6 hours, and when the zinc concentration of the soil contaminated with zinc is 1500 mg / kg or more and less than 4000 mg / kg, In the first stage extractor and the second stage extractor, the extract and the zinc-contaminated soil are reacted for 0.5 to 0.6 hours to separate the purified soil, and when the zinc concentration of the soil contaminated with zinc is 4000 mg / kg or more and 5000 mg / kg or less. There, by 0.5 ~ 0.6 hours of reaction, respectively the extract and zinc contaminated soil from the first-stage extractor, two-stage and three-stage extractor extractor being done to remove the purified soil,
A stripping tank for selectively extracting heavy metals in the solvent by mixing the solvent and the stripping liquid discharged through the three-stage extractor, the two-stage extractor and the first-stage extractor continuously, and resupplying the purified solvent to the three-stage extractor; Zinc contaminated soil purification system using a solvent extraction method further comprises a heavy metal concentration tank for receiving and storing the heavy metal extracted from the stripping tank.
The method according to claim 3,
A sensor unit for measuring the zinc concentration of the extract liquid discharged from the first stage extractor, the second stage extractor, and the three stage extractor in real time;
A monitor for receiving information on the real-time concentration of the extract from the sensor unit and outputting the information visually recognizable; And
Receiving the increase and decrease signal from the monitor to adjust the flow rate of the solvent in accordance with the increase and decrease of the zinc content of the extract liquid comprising a control unit for increasing or decreasing the flow rate of the solvent to the three-stage extractor, zinc contaminated soil purification using a solvent extraction method system.

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