TWI537067B - A method for decontamination of brick and concrete contaminated by radionuclide - Google Patents

Description

Method for decontamination of bricks and concrete blocks

The invention relates to a method for decontaminating bricks and concrete blocks, in particular to a method for treating radioactive metal cores in bricks or concrete blocks, reducing the content of radioactive metal species in bricks or concrete blocks, and making bricks Or the concrete block can be reused or settled.

With the advancement of domestic industry and the continuous development of science and technology, human demand for electricity is increasing. Although the world's energy consumption is dominated by petroleum, coal, natural gas and other fossil fuels, as fossil fuels emit a large amount of waste gas, pollute the environment, and emit a large amount of carbon dioxide, causing the global warming effect, countries began to develop nuclear power to meet the demand for electricity. . Although nuclear power is said to be clean and safe, there are still examples of nuclear power accidents around the world, such as the Chernobyl incident and the Fukushima nuclear disaster. The 2011 311 earthquake in Japan caused the Fukushima nuclear power plant to be hit hard, and the surrounding soil and buildings were seriously polluted. In the future, a large amount of topsoil and building rubble needed to be removed and disposed of. In addition, the decommissioning work of China's nuclear power plants is imperative. When the nuclear power plants are decommissioned, some of the concrete surfaces of the buildings need to be treated. Most of them contain radioactive metal species such as plutonium. The degree of concrete pollution is related to the location of the pollution and the type of material. The depth of contamination can range from a few millimeters to several centimeters.

Conventional concrete surface decontamination techniques include mechanical scooping, shaving, cutting/sawing, grinding and sand blasting (wet abrasive). Demolition techniques include jackhammer, drilling/breaking and blasting.

Although the prior art has provided activated carbon regeneration technology and soil remediation methods, it has not achieved the goals of simple process, low cost, low waste liquid and low energy consumption. Accordingly, it is necessary to provide a method for decontaminating bricks and concrete blocks capable of treating metal radioactive metal species in bricks or concrete blocks such as activated carbon, soil, and building rubble, and capable of reducing energy and water consumption.

The main object of the present invention is to provide a method for decontaminating bricks and concrete blocks, which is capable of effectively removing radioactive metal cores in bricks or concrete blocks.

A second object of the present invention is to provide a method for decontaminating bricks and concrete blocks, which is capable of reducing the consumption of organic solvents and water resources.

In order to achieve the foregoing object, the method for decontaminating bricks and concrete blocks according to the present invention comprises the following steps: a pulverizing step: pulverizing bricks or concrete blocks with a pulverizing device; and a flow washing step: locating bricks Or the concrete block is placed in a chamber, and a remover is introduced into the chamber to wash the brick or the concrete block, wherein the pressure in the chamber is 74 bar or more, and the temperature in the chamber is 32 ° C or more, the removal The agent comprises a supercritical carbon dioxide fluid, a co-solvent and a metal complex; the displacement separation step is: introducing a replacement fluid into the chamber to replace the remover in the chamber, and then replacing the replacement fluid with the brick or Separation of concrete blocks; and The pickling step: the auxiliary solvent and the metal complex are washed with an acid solution to separate the metal core species.

In the method for decontaminating bricks and concrete blocks of the present invention, the metal complexing agent may be selected from Bis-trifluoroethyldithiocarbamate (bis-trifluorodithiocarbamate, FDDC for short) and Diethyldithiocarbamate (diethyldisulfide). Aminocarbamic acid (DDC), Dipropyl-dithiocarbamate (dipropyldithiocarbamate, P3DC for short), Dibutyldithiocarbamate (dibutyldithiocarbamate, BDC for short), Dipentyldithiocarbamate (dipentyl) Thiocarbamate, abbreviated as P5DC), Dihexyldithiocarbamate (dihexyldithiocarbamate, abbreviated as P6DC) or Pyrrolidine-dithiocarbamate (Pyrrolidine Dithiocarbamate, PDC for short), Acetylacetone (2,4- Pentanedione (AA), Trifluoroacetylacetone (1,1,1-trifluoro-2,4-pentanedione, abbreviated as TFA), Hexafluoroacetyl-acetone (hexafluoroacetone, HFA for short), Thenoyltrifluoroacetone (2-thiophene) Formazan trifluoroacetone (TTA) or Heptafluorobutanoyl-pivaroylmethane (2,2-dimethyl-6,6,7,7,8,8,8,-heptafluoro-3,5-octanedione, abbreviated as FOD ), Tributylphosphate (tributyl phosphate, TBP for short), Tribut Yylphosphine oxide (TBPO), Trioctylphosphine oxide (TOPO), Triphenyl-phosphine oxide (TPPO), Bis (2,4,4,- Trimethylpentyl)phosphinic acid (bis(2,4,4-trimethylpentyl)phosphonic acid, referred to as Cyanex 272), Bis(2,4,4,-trimethyl-pentyl)dithiophosphinic acid (two (2,4,4) -trimethylpentyl)dithiophosphinic acid, abbreviated as Cyanex 301), Bis(2,4,4,-trimethylpentyl)monothiophosphinic acid (bis(2,4,4-trimethylpentyl)thiophosphinic acid , referred to as Cyanex 302), Di(2-ethylhexyl)phosphoric acid (di(2-ethylhexyl)phosphoric acid, abbreviated as D ₂ EHPA) or Crown ether (crown ether).

In the method for decontaminating bricks and concrete blocks of the present invention, the metal composite agent is more preferably Di(2-ethylhexyl)phosphoric acid.

In the method for decontaminating bricks and concrete blocks of the present invention, the auxiliary solvent is preferably a low carbon number alkane or an alcohol having a carbon number of from 1 to 6, more preferably selected from methanol or n-hexane.

In the method for decontaminating bricks and concrete blocks of the present invention, the pressure in the chamber is 74 bar or more, preferably between 100 bar and 350 bar.

In the method for decontaminating bricks and concrete blocks of the present invention, the temperature in the chamber is 32 ° C or higher, preferably between 35 ° C and 140 ° C.

In the method for removing bricks and concrete blocks of the present invention, the weight percentage of the auxiliary solvent to the remover is preferably 1.0 to 20.0%, and the weight ratio of the metal complex to the remover is preferably 0.1 to 9.0%. The weight percentage of the supercritical carbon dioxide fluid to the remover is preferably from 79.9 to 98.9%.

1‧‧‧Smashing step

2‧‧·flow washing steps

3‧‧‧ Displacement separation step

4‧‧‧ pickling step

5‧‧‧Mixed components

51‧‧‧CO2 tank

52‧‧‧Secondary solvent and metal complex tank

53‧‧ ‧ room

6‧‧‧ Pressure components

61‧‧‧First back pressure valve

62‧‧‧Second back pressure valve

7‧‧‧Separation tank

71‧‧‧First exit

72‧‧‧second exit

H‧‧‧heater

C‧‧‧cooler

P‧‧‧Infusion pump

F‧‧‧Flow Regulator

First Figure: Step block diagram of the present invention.

Second figure: Schematic diagram of the configuration of the supercritical fluid device provided in this embodiment.

Fig. 3 is a graph showing the removal rate of bismuth metal on the pulverized brick of this embodiment.

Fig. 4 is a graph showing the removal rate of bismuth metal on the pulverized concrete block of this embodiment.

The above and other objects, features and advantages of the present invention will become more apparent and understood. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention, together with the drawings, are described in detail as follows: Referring to the first figure, the method for decontaminating bricks and concrete blocks of the present invention comprises: a pulverizing step 1, first class Washing step 2, a displacement separation step 3, and a pickling step 4.

Crushing step 1: The brick or concrete block is pulverized by a pulverizing device to increase the loading amount and the contact area.

Flow washing step 2: placing a metal-contaminated brick or concrete block in a chamber, and passing a remover into the chamber to wash the brick or concrete block, the remover comprising a supercritical carbon dioxide fluid, A co-solvent and a metal complex. Wherein, the pressure and temperature in the chamber are defined by the working pressure and temperature of the supercritical carbon dioxide fluid, which is understood by those of ordinary skill in the art, and as shown in this embodiment, the pressure in the chamber is 74 bar. In particular, it is preferable to maintain the pressure in the chamber at about 100 bar to 350 bar; the temperature in the chamber is 32 ° C or higher, and it is preferable to maintain the temperature in the chamber at about 35 ° C to 120 ° C. More specifically, the auxiliary solvent contained in the remover helps to dissolve the metal composite agent, and helps the metal composite agent to radioactive metal in bricks or concrete blocks by temperature and pressure conditions in the chamber. The nucleus is dissolved in the remover, thereby desorbing the radioactive metal species in the brick or concrete block, thereby reducing the content of the radioactive metal species adsorbed on the brick or concrete block.

For example, the auxiliary solvent is used as a diluted solution of the metal complexing agent, and the auxiliary solvent is preferably a low carbon number (C1~C6) alkane or alcohol, especially methanol or n-hexane as a metal complexing agent. The solution not only helps to improve the adsorption of the metal complexing agent, but also helps to change the polar characteristics of the supercritical carbon dioxide fluid; the metal complexing agent can be selected as a metal chelate or coordinated organic compound, and the metal complexing agent can be substantially Divided into four categories: (1) dithiocarbamate metal complex Mixture, (2) diketone metal compounding agent, (3) organophosphorus metal compounding agent, and (4) macrocyclic metal compounding agent.

Dithiocarbamate metal complexing agents include, for example, Bis-trifluoroethyldithiocarbamate (bis-trifluorodithiocarbamate, FDDC for short), Diethyl-dithiocarbamate (diethyldithiocarbamate, DDC for short) ), Dipropyldithiocarbamate (dipropyldithiocarbamate, P3DC for short), Dibutyldithiocarbamate (dibutyldithiocarbamate, BDC for short), Dipentyl-dithiocarbamate (dipentyldithiocarbamate) , referred to as P5DC), Dihexyldithiocarbamate (dihexyldithiocarbamate, abbreviated as P6DC) or Pyrrolidinedithiocarbamate (pyrrolidine dithiocarbamate, abbreviated as PDC).

Diketone metal complexing agents include, for example, Acetylacetone (2,4-pentanedione, AA for short), Trifluoroacetylacetone (1,1,1-trifluoro-2,4-pentanedione, abbreviated as TFA), Hexafluoroacetylacetone (hexafluoroethyl)醯Acetone, abbreviated as HFA), Thenoyltrifluoroacetone (2-thiophene guanidine trifluoroacetone, abbreviated as TTA) or Heptafluorobutanoyl-pivaroylmethane (2,2-dimethyl-6,6,7,7,8,8,8,-seven Fluorin-3,5-octanedione, abbreviated as FOD).

Organophosphorus metal complexing agents include, for example, Tributylphosphate (tributyl phosphate, TBP for short), Tributylphosphine oxide (TBPO), Trioctylphosphine oxide (TOPO), Triphenylphosphine oxide (oxidized three) Phenylphosphine (TPPO), Bis(2,4,4,-trimethylpentyl)phosphinic acid (bis(2,4,4-trimethylpentyl)phosphonic acid, Cyanex 272 for short), Bis (2,4, 4,-trimethylpentyl)dithio-phosphinic acid (bis(2,4,4-trimethylpentyl)dithiophosphinic acid, referred to as Cyanex 301), Bis(2,4,4,-trimethyl-pentyl)monothiophosphinic acid (bis(2,4,4-trimethylpentyl)phosphinic acid, referred to as Cyanex 302) or Di(2-ethylhexyl)phosphoric acid (abbreviated as D ₂ EHPA).

Macrocyclic metal complexes such as Crown ether.

This embodiment was selected as D ₂ EHPA and can be used in conjunction with supercritical carbon dioxide fluid and the co-solvent for base metals on bricks or concrete blocks. Since carbon dioxide is easy to obtain, and it is colorless, odorless, non-toxic, non-explosive, non-flammable, and non-corrosive, it has high safety.

In addition, the supercritical carbon dioxide fluid helps to uniformly contact the brick or concrete block, and the radioactive metal nucleus is released by the polarity of the supercritical carbon dioxide fluid, which grabs the brick or concrete block. The radioactive metal species is dissolved in the remover. Thus, the method for decontaminating bricks and concrete blocks of the present invention can improve the compounding efficiency of base metals in bricks or concrete blocks by the action of the metal compounding agent and the supercritical carbon dioxide fluid.

Displacement separation step 3: a replacement fluid is introduced into the chamber to replace the remover in the chamber, and the replacement fluid is separated from the brick or concrete block. More specifically, the replacement fluid may be selected as a supercritical fluid. In this embodiment, the supercritical carbon dioxide fluid is selected as a replacement fluid to displace the remover in the chamber, and the pressure in the chamber is decreased. The supercritical carbon dioxide fluid as the replacement fluid and the supercritical carbon dioxide fluid in the remover become the gas phase, and the carbon dioxide gas can be directly discharged into the external environment or recovered and reused; in this embodiment, the chamber is used. The pressure is reduced to the same temperature as the outside of the chamber and will be oxidized The carbon gas is directly discharged to the outside of the chamber, and the brick or concrete block in the chamber has completed the removal of the radioactive metal species.

Pickling step 4: mixing the acid solution with the auxiliary solvent containing the radioactive metal and the metal complexing agent, dissolving the radioactive metal in the acid solution, and removing the acid solution containing the radioactive metal, thereby recovering the auxiliary solvent and the metal. Compounding agent. Further, the acid solution may be repeatedly subjected to a recovery procedure of the auxiliary solvent and the metal complex until the radioactive metal in the acid solution is saturated.

Thus, the method for decontaminating bricks and concrete blocks of the present invention can reduce the use of organic solvents, and does not require excessive energy to heat the bricks or concrete blocks and the remover, nor does it require a large amount of aqueous solution. The brick or concrete block is cleaned. In addition, the organic solvent is not left in the recycled brick or concrete block, and the radioactive metal species in the brick or concrete block can be reliably reduced.

In order to confirm the method for decontaminating bricks and concrete blocks of the present invention, it is possible to effectively reduce the radioactive metal species in bricks or concrete blocks. In this embodiment, 3 kg of crushed bricks and crushed concrete blocks and the like are used. They were immersed in a 5 liter aqueous solution of cerium nitrate (30 g/L) for 48 hr, and dried to form a brick or concrete block sample simulating metal contamination, and the following tests were carried out: (A) Brick or concrete block samples Analysis of base metal content, (B) analysis of base metal content of auxiliary solvent and metal composite, (C) removal of base metal test in crushed brick samples, and (D) removal of base metal test in crushed concrete block samples.

(A) Analysis of bismuth metal content in brick or concrete block samples

The method for detecting the bismuth metal content of the brick or concrete block sample in the present embodiment is analyzed by an inductively coupled plasma atomic emission spectrometer (ICP-OES), and the analysis method is as follows:

1. Place about 0.1g (W _S ) brick or concrete block in the microwave digestion tank;

2. Add 4.5 mL of concentrated nitric acid and 1.5 mL of concentrated hydrochloric acid in sequence;

3. Place for 20 minutes to complete the reaction, and place the digestion tank in the microwave digester;

4. The microwave digestion temperature is set to 220 ° C, the heating time is set to 20 min, and the holding time is 50 min;

5. The digester is placed in a water bath for 20 minutes to be cooled, and the digested solution is quantified to 25 mL with deionized water;

6. Filter the above digestive juice, place it in an empty test tube, and seal it with a parafilm for analysis.

7. The obtained barium metal concentration C _{S is} multiplied by the volume of 0.025L and the weight of the cleaning block or concrete block W _ST (the crushed brick is loaded with 280g, the crushed concrete block is loaded with 370g), and then removed. With the weight of the brick or concrete block W _S placed in the digestion tank, the weight of the base metal W _{SSr which is} not washed out on the brick or concrete block is _known . For example, the following relation W _SSr = C _S × 0.025 × W _ST / W _S .

The content of base metal in each gram sample of the metal-contaminated crushed brick of the present embodiment is about 2.08 mg, and the content of base metal in each gram sample of the pulverized concrete block is about 8.33 mg.

(B) Analysis of base metal content of auxiliary solvent and metal composite agent

The detection method of the ruthenium metal content of the auxiliary solvent and the metal composite agent in the present embodiment is analyzed by an inductively coupled plasma atomic emission spectrometer (ICP-OES), and the analysis method is as follows: 1. Collecting at different time points The auxiliary solvent and the metal compound are weighed and deducted from the empty bottle weight to obtain W _E ; 2. The solution is quantified to 25 mL and weighed to obtain the extract density D _E , and the liquid volume V _{E is} W _E to D _E The ratio, such as the relationship V _E = W _E / D _E ; 3. Take 1 mL of the extract in a test tube, placed in an oven at 60 ° C to remove the co-solvent, then add 0.5 mL of n-hexane, followed by 10 mL of 10% aqueous nitric acid After ultrasonic shock for 10 min, let stand for 16 hr, remove the upper layer liquid to retain the lower layer stripping solution, and obtain the concentration of base metal C _E by ICP analysis; 4. Obtain the concentration of base metal C _E by analysis, multiply by the volume of the stripping solution 0.01 The weight of the base metal in the extract can be obtained by L and V _E . For example, the following relationship W _ESr = C _E × 0.01 × V _E .

(C) Removal of base metal test in crushed brick samples

The present embodiment provides a supercritical fluid device as shown in the second figure, comprising a mixing assembly 5, a pressure component 6 and a separation tank 7, and the mixing assembly 5 and the separation tank 7 are connected to each other, and The internal pressure of the mixing unit 5 and the separation tank 7 is controlled by the pressure unit 6.

The mixing assembly 5 is provided with a carbon dioxide tank 51, a solvent and metal complex tank 52, and a chamber 53. The carbon dioxide tank 51 and the auxiliary solvent and metal compound tank 52 are in communication with the chamber 53. The tank 51 is for accommodating carbon dioxide, and the auxiliary solvent and the metal compound tank 52 are used for accommodating the auxiliary solvent (such as methanol or n-hexane) and the metal compounding agent (such as D ₂ EHPA), and the chamber 53 is For accommodating a sample to be processed, the carbon dioxide tank 51 and the auxiliary solvent and metal compound tank 52 have the function of adjusting the internal temperature and pressure of the tank (the heater H or the cooler C as shown in the figure), each of which is An infusion pump P and a flow rate regulator F are connected to the internal solution to the chamber 53.

The pressure component 6 includes a first back pressure valve 61 and a second back pressure valve 62, wherein the first back pressure valve 61 controls the internal pressure of the chamber 53, and the second back pressure valve 62 controls the The internal pressure of the separation tank 7 is separated.

The separation slot 7 includes a first outlet 71 and a second outlet 72. The first outlet 71 is for gas to escape into the environment or a collection tank (not shown), and the second outlet 72 can The auxiliary solvent mixed with the base metal and the metal composite agent flow out.

The operation of the supercritical fluid device of the present embodiment is as follows: a brick or concrete block sample is placed in the chamber 53, the temperature and pressure conditions of the chamber 53 are brought to a preset value, and the operating fluid is adjusted to flow into the chamber. The volume flow rate of the chamber 53 is 4.5 mL/min (in which the auxiliary solvent is mixed with the metal complexing agent), and is set to flow at a carbon dioxide flow rate of 30 g/min for a period of time (for example, 3 to 6 hours) to start removing the radioactive metal of the sample. a nuclear species; the operating fluid flows from the chamber 53 to the separation tank 7, and the pressure of the separation tank 7 is lowered to 40 bar to vaporize the supercritical carbon dioxide gas, which can be recycled for reuse or directly discharged to the environment. In the interior of the separation tank 7, there is left a solution of a co-solvent and a metal complex, which comprises a metal compounding agent and a metal compounding agent which has been combined with cerium, and the brick or concrete in the chamber 53 The block sample has removed the base metal therein. Finally, the acid solution is uniformly mixed with the auxiliary solvent and the metal complex extract, so that the base metal is dissolved in the acid solution, and the acid solution containing the base metal is removed, thereby recovering the auxiliary solvent and the metal complex.

For example, in the first embodiment, the pulverized brick sample (about 280 g) is first placed in the chamber 53, and at 140 ° C, the auxiliary solvent (methanol), the metal composite agent (D _{2 )} EHPA) is mixed with the supercritical carbon dioxide fluid at a preferred weight percentage of 5.3%, 6.4%, and 88.3%, respectively, with a carbon dioxide flow rate of 30 g/min, and a flow rate of the auxiliary solvent and metal complex flow rate of 4.5 mL/min. Through the chamber 53, the sample of the crushed brick is taken out at the end of the washing time, and the total content of the metal ruthenium of the processed and untreated crushed brick samples is 195.9 mg and 581.4 mg, respectively, and the metal cerium removal rate can be calculated. Up to 66.3%, the extraction curve is shown in the third figure.

(D) Removal of base metal test in samples of crushed concrete blocks

The second embodiment then placed a sample of pulverized concrete block (about 370 grams) in the chamber 53, and at 60 ° C, the auxiliary solvent (methanol), the metal compounding agent (D ₂ EHPA) and the super The critical carbon dioxide fluid is mixed at 4.4%, 6.5%, and 89.1%, respectively, at a flow rate of 30 g/min, and the flow rate of the auxiliary solvent and the metal complex at a flow rate of 4.5 mL/min flows through the chamber 53. At the end of the washing time, the brick or concrete block sample was taken out, and the bismuth metal contents of the treated and untreated brick or concrete block samples were 1927.1 mg and 3080.7 mg, respectively, and the bismuth metal removal rate was calculated to be 37.4. %, the extraction curve is shown in the fourth figure.

The brick or concrete block samples processed in the first and second embodiments were analyzed for the removal rate of the base metal in the manner of tests (A) and (B); thus, it was known that methanol, D ₂ EHPA and supercritical carbon dioxide fluid were used. It is indeed possible to remove the ruined bricks and crush the bismuth metal in the concrete block.

It can be seen from the above results that the present invention can simultaneously reduce the radioactive metal species content in the brick or concrete block, and according to the radioactive gold contained in the brick or concrete block. The nucleus content, with methanol as the auxiliary solvent, can improve the efficiency of processing the base metal. It can be seen from the above that the method for decontaminating bricks and concrete blocks of the present invention can effectively improve the treatment efficiency of radioactive metal species in bricks or concrete blocks.

Accordingly, the method for decontaminating bricks and concrete blocks of the present invention is capable of providing bricks or concrete at a lower temperature and pressure under the conditions of lower energy consumption by using the supercritical carbon dioxide fluid, the auxiliary solvent and the metal compounding agent. The radioactive metal nucleus in the block has the effect of improving the processing efficiency of the radioactive metal nucleus.

The method for decontaminating bricks and concrete blocks of the invention can reduce the consumption of organic solvents and water resources, so as to achieve environmentally friendly and resource-saving effects.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

1‧‧‧Smashing step

2‧‧·flow washing steps

3‧‧‧ Displacement separation step

4‧‧‧ pickling step

Claims (10)

A method for decontaminating bricks and concrete blocks comprises the following steps: a pulverizing step: pulverizing bricks or concrete blocks contaminated with metal by a pulverizing device; and washing step: pulverizing and contaminating with metal a brick or concrete block is placed in a chamber, and a remover is introduced into the chamber to wash the brick or the concrete block, and the remover comprises a supercritical carbon dioxide fluid, a co-solvent and a metal composite agent, wherein The auxiliary solvent contained in the remover helps dissolve the metal composite agent, and helps the metal composite agent dissolve the radioactive metal nucleus in the brick or concrete block in the remover, thereby making the brick or concrete block The radioactive metal species is desorbed to reduce the content of radioactive metal species adsorbed on the brick or concrete block; the displacement separation step is to pass a replacement fluid into the chamber to replace the remover in the chamber, and then The replacement fluid is separated from the brick or concrete block to complete the removal of the radioactive metal species from the brick or concrete block in the chamber; and the pickling step: the radioactive gold is contained Auxiliary solvents and metal complexing agent rinsed with acid. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the metal compounding agent is Bis-trifluoroethyldithiocarbamate (bis-trifluorodithiocarbamate, FDDC for short), Diethyldithiocarbamate ( Diethyldithiocarbamic acid (DDC), Dipropyl-dithiocarbamate (dipropyldithiocarbamate, P3DC for short), Dibutyldithiocarbamate (dibutyldithiocarbamate, BDC for short), Dipentyldithiocarbamate (dipentyldithiocarbamate, abbreviated as P5DC), Dihexyldithiocarbamate (dihexyldithiocarbamate, P6DC for short) or Pyrrolidine-dithiocarbamate (Pyrrolidine dithiocarbamate, PDC for short), Acetylacetone (2,4-pentanedione, abbreviated as AA), Trifluoroacetylacetone (1,1,1-trifluoro-2,4-pentanedione, abbreviated as TFA), Hexafluoroacetyl-acetone (hexafluoroacetone, HFA for short), Thenoyltrifluoroacetone (2-thiophene guanidine trifluoroacetone, abbreviated as TTA) or Heptafluorobutanoyl-pivaroylmethane (2,2-dimethyl-6,6,7,7,8,8,8,-heptafluoro-3,5-octyl) Diketone, abbreviated as FOD), Tributylphosphate (tributyl phosphate, TBP), Tributylphosphine oxide (TBPO), Trioctylphosphine oxide (TOPO), Triphenylphosphine oxide (TPPO), Bis (2,4,4 ,-trimethylpentyl)phosphinic acid (bis(2,4,4-trimethylpentyl)phosphonic acid, referred to as Cyanex 272), Bis(2,4,4,-trimethylpentyl)dithiophosphinic acid (two (2,4,4) -trimethylpentyl)dithiophosphinic acid, abbreviated as Cyanex 301), Bis(2,4,4,-trimethylpentyl)monothio-phosphinic acid (bis(2,4,4-trimethylpentyl)thio Phosphonic acid, referred to as Cyanex 302), Di(2-ethylhexyl)phosphoric acid (abbreviated as D ₂ EHPA) or Crown ether (crown ether). The method for decontaminating bricks and concrete blocks according to claim 1, wherein the metal composite agent is Di(2-ethylhexyl)phosphoric acid. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the auxiliary solvent is a low carbon number alkane or an alcohol having a carbon number of 1 to 6. A method for decontaminating bricks and concrete blocks according to claim 4, wherein the auxiliary solvent is methanol or n-hexane. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the pressure in the chamber is 74 bar or more. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the pressure in the chamber is between 100 bar and 350 bar. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the temperature in the chamber is 32 ° C or higher. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the temperature in the chamber is between 35 ° C and 140 ° C. The method for decontaminating bricks and concrete blocks according to claim 1, wherein the auxiliary solvent accounts for 1.0-20.0% by weight of the remover, and the metal composite agent accounts for 0.1% by weight of the remover. ~9.0%, the supercritical carbon dioxide fluid accounts for 79.9~98.9% by weight of the remover.