CN110369471A - A kind of method of chromium-polluted soil reparation - Google Patents
A kind of method of chromium-polluted soil reparation Download PDFInfo
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- CN110369471A CN110369471A CN201910836932.2A CN201910836932A CN110369471A CN 110369471 A CN110369471 A CN 110369471A CN 201910836932 A CN201910836932 A CN 201910836932A CN 110369471 A CN110369471 A CN 110369471A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/08—Reclamation of contaminated soil chemically
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/10—Reclamation of contaminated soil microbiologically, biologically or by using enzymes
- B09C1/105—Reclamation of contaminated soil microbiologically, biologically or by using enzymes using fungi or plants
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Abstract
The present invention relates to a kind of methods of chromium-polluted soil reparation, the method releases chromium by using acidification, chemistry and biomass reduction, the mode that phytoremediation combines, acid soluble hexavalent chromium in soil and water soluble hexavalent chromium are first discharged into slurry, slurry is separated by solid-liquid separation, it is transferred to Cr VI in filtrate, it is effectively separated with soil, the hexavalent chrome reduction in filtrate is precipitated into chromium hydroxide again, carry out resource recycling, remaining Cr VI uses electronation and the long-acting reduction of biomass and phytoremediation again in soil after separating and filtering, " brightness reversion " after solving the problems, such as chromium-polluted soil reparation.
Description
Technical field
The present invention relates to technical field of soil remediation more particularly to a kind of methods of chromium-polluted soil reparation.
Background technique
The chromium-polluted soil in China is mainly that the chromium slag stockpiling discharged by chrome salt production enterprise and resettlement enterprise leave place
It is caused.After the founding of the state, China successively has chromium salt factory 63, is 2 times of external chrome salt production enterprise quantity summation, due to chromic salts
Traditional processing technology falls behind, and 1 ton of chromic salts product of every production about generates 1.5~3 tons of chromium slags.According to statistics, China in 2005 adds up heap
It deposits and leaves more than 600 ten thousand tons of chromium slag, all removing toxic substances was completed by 2012.But during chromium slag is stored up for a long time, do not take mostly anti-
Seep, flood control, anti-rain and it is anti-fly upward measure, the chromium slag dust of weathering is flown upward with the wind to be deposited to nearby soil, the chromium slag that drenches with rain and causes
Cr (VI) penetrates into the pollution of chromium that the factors such as soil cause soil.
Currently, the method for repairing hexavalent chromium polluted soil is summed up that there are two main classes both at home and abroad: first is that migration is strong,
The high hexavalent chrome reduction of toxicity strong, small toxicity trivalent chromium at stability；Second is that chromium is removed from contaminated soil.Electrodynamics
Recovery technique can realize the separation of chromium in soil, but project amount is big, and cost is high, and there are certain requirements to soil, using having
Limitation.Chemical leaching technology is mainly used in sand soil property, and for silt, clay soil property, the separation of chromium is difficult.Therefore,
Stabilisation/curing technology of electronation is most common technology in most engineering since repair time is short, effect is good, low energy consumption,
But soil often will appear " brightness reversion " phenomenon after repairing, it would be highly desirable to research and develop a kind of effective reparation control for severe chromium-polluted soil
Key technology processed is to solve this outstanding problem.
Summary of the invention
In view of problems of the prior art, the present invention provides a kind of method of chromium-polluted soil reparation, the method
By to Cr VI and soil efficiently separate and soil in the remaining long-acting reduction of Cr VI, thoroughly solve pollution of chromium
" brightness reversion " problem after soil remediation, had not only realized the Long term control and ecological recovery of chromium-polluted soil, but also realized in soil
The recycling of chromium resource, has a good application prospect.
To achieve this purpose, the present invention adopts the following technical scheme:
The present invention provides a kind of method of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil and ore grinding solution are mixed and carries out ore grinding, obtain slurry；
(2) slurry and sulfuric acid and the rework solution mixing obtained step (1) carries out acidification, obtains acidification slurry
Material, is separated by solid-liquid separation, and is obtained processing extraction raffinate and is pre-processed soil；
(3) to the resulting pretreatment soil of step (2) and reducing agent mixing carry out reduction treatment, later be added neutralizer into
Row neutralisation treatment obtains removing toxic substances soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation and plants plant
Object is repaired；
Wherein, in the resulting processing extraction raffinate of step (2) be added reduzate carry out reduction treatment, later be added precipitating reagent into
Row precipitating operation, obtains filtrate and filter cake containing chromium through being separated by solid-liquid separation, and filtrate distinguishes return step (1) and is used as ore grinding solution and step
(2) it is used as rework solution, filter cake containing chromium carries out resource and changes utilization.
A kind of method of chromium-polluted soil reparation provided by the invention, releases chromium, chemistry and biomass also by using acidification
The mode that former, phytoremediation combines, first discharges into slurry for acid soluble hexavalent chromium in soil and water soluble hexavalent chromium, to slurry
Material is separated by solid-liquid separation, and is transferred to Cr VI in filtrate, is effectively separated with soil, then by the hexavalent chrome reduction in filtrate
Precipitate into chromium hydroxide, carry out resource recycling, after separating and filtering in soil remaining Cr VI use again electronation and
The long-acting reduction of biomass and phytoremediation, " brightness reversion " after solving the problems, such as chromium-polluted soil reparation.
As currently preferred technical solution, the content of Cr VI is 300- in step (1) described chromium-polluted soil
20000mg/kg, for example, 300mg/kg, 500mg/kg, 800mg/kg, 1000mg/kg, 2000mg/kg, 3000mg/kg,
4000mg/kg, 5000mg/kg, 8000mg/kg, 10000mg/kg, 15000mg/kg or 20000mg/kg etc., but simultaneously not only limit
Equally applicable, the preferably 5000-20000mg/kg in other unlisted numerical value in cited numerical value, the numberical range.
It, will using wet-milling in order to guarantee capable of thoroughly dissolving out from chromium-polluted soil for acid soluble hexavalent chromium in the present invention
The soil of containing chromium slag is levigate.
As currently preferred technical solution, step (1) ore grinding is wet-milling.
Preferably, in step (1) described slurry chromium-polluted soil particle granularity be 20-200 mesh, such as 20 mesh, 50 mesh,
80 mesh, 100 mesh, 120 mesh, 150 mesh, 180 mesh or 200 mesh etc., it is not limited to cited numerical value, in the numberical range its
His unlisted numerical value is equally applicable, preferably 50-200 mesh.
Preferably, the content of chromium-polluted soil described in step (1) described slurry be 10-90%, such as 10%, 20%,
30%, 40%, 50%, 60%, 70%, 80% or 90% etc., it is not limited to cited numerical value, in the numberical range its
His unlisted numerical value is equally applicable, preferably 20-70%.
In the present invention, the Cr VI in severe chromium-polluted soil is divided into acid soluble hexavalent chromium and water soluble hexavalent chromium, this two
The different Cr VI of kind has very big difference on difficulty of governance.Water soluble hexavalent chromium is adsorbed on soil, is easy to be flooded out, can
To carry out removing toxic substances improvement with reducing agent.And acid soluble hexavalent chromium derives from dicalcium silicate-chromium that chromium salt production calcine technology is formed
Sour calcium (2CaOSiO2-CaCrO4) and calcium aluminoferrite-calcium chromate (4CaOAl2O3·Fe2O3-CaCrO4) etc. solid solutions, due to
These CaCrO4It is present in dicalcium silicate, calcium aluminoferrite or calcium aluminate intracell, usually destroys solid solution lattice with strong acid
It could be by CaCrO4It releases, water soluble hexavalent chromium is formed, to quickly be administered.Using the sulfuric acid of sufficient amount by chromium slag
In dicalcium silicate, calcium aluminate, calcium aluminoferrite decompose acid-soluble CaCrO completely4Be converted to water soluble hexavalent chromium, react as
Shown in lower:
Ca2SiO4-CaCrO4+2H2SO4+(x-2)H2O=SiO2.xH2O+2CaSO4+CaCrO4
5CaO·3Al2O3-CaCrO4+5H2SO4+(3y-5)H2O=3 (Al2O3·yH2O)+5CaSO4+CaCrO4
4CaO·3Al2O3·Fe2O3-CaCrO4+4H2SO4+(y+z-4)H2O=Al2O3·yH2O+Fe2O3·zH2O+
4CaSO4+CaCrO4
As currently preferred technical solution, the concentration of step (2) described sulfuric acid is 50-98%, such as 50%,
55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 98% etc., it is not limited to cited numerical value, the number
It is equally applicable to be worth other unlisted numerical value in range, preferably 80-98%.
Preferably, the additional amount of step (2) described sulfuric acid is with H2SO4Meter and chromium-polluted soil quality described in the slurry
Ratio be 0.01:1-0.8:1, such as 0.01:1,0.02:1,0.03:1,0.04:1,0.05:1,0.06:1,0.07:1,
0.08:1,0.09:1,0.1:1,0.2:1,0.3:1,0.4:1,0.5:1,0.6:1,0.7:1 or 0.8:1 etc., it is not limited to
Cited numerical value, other interior unlisted numerical value of the numberical range are equally applicable, preferably 0.1:1-0.5:1.
Preferably, the time of step (2) described acidification be 0.5-12h, such as 0.5h, 1h, 1.5h, 2h, 2.5h,
3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, 10.5h, 11h, 11.5h or
12h etc., it is not limited to cited numerical value, other interior unlisted numerical value of the numberical range are equally applicable, preferably 1-
6h。
, can be by hexavalent chrome reduction at trivalent chromic ion using reducing agent in acid medium in the present invention, then add alkali
PH value is adjusted, so that trivalent chromic ion is formed chromium hydroxide precipitation, achievees the purpose that removing toxic substances, specific reaction equation is as follows:
2CaCrO4+4H2SO4+2FeSO4=Cr2(SO4)3+Fe2(SO4)3+4H2O
Cr2(SO4)3+Ca(OH)2=Cr (OH)3↓+CaSO4↓
As currently preferred technical solution, step (3) reducing agent is ferrous sulfate, vulcanized sodium, calcium sulfide, two
One of sulfur oxide, sodium thiosulfate or sodium sulfite or at least two combination, for example, the group of ferrous sulfate and vulcanized sodium
It closes, the combination of vulcanized sodium and calcium sulfide, the combination of calcium sulfide and sulfur dioxide, the combination of sulfur dioxide and sodium thiosulfate or sulphur
Sodium thiosulfate and the combination of sodium sulfite etc., but it is not limited only to cited combination, other unlisted combinations in combination range
It is equally applicable, preferably one of ferrous sulfate, vulcanized sodium or calcium sulfide or at least two combination.
Preferably, in the additive amount of step (3) described reducing agent and the pretreatment soil needed for remnants hexavalent chrome reduction
The ratio of theoretical amount is 1:1-8:1, such as 1:1,2:1,3:1,4:1,5:1,6:1,7:1 or 8:1 etc., it is not limited to listed
The numerical value of act, other interior unlisted numerical value of the numberical range are equally applicable, preferably 2:1-4:1.
Preferably, the initial pH value of step (3) described reduction treatment be 0.5-5, such as 0.5,1,1.5,2,2.5,3,
3.5,4,4.5 or 5 etc., it is not limited to cited numerical value, other interior unlisted numerical value of the numberical range are equally applicable,
Preferably 1-5.
Preferably, the time of step (3) described reduction treatment be 0.5-24h, such as 0.5h, 1h, 2h, 3h, 4h, 5h, 6h,
7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h or for 24 hours etc., but simultaneously
It is not limited only to cited numerical value, other unlisted numerical value are equally applicable in the numberical range, preferably 6-18h.
Preferably, step (3) neutralizer is in calcium oxide, calcium carbonate, calcium hydroxide, sodium carbonate or sodium hydroxide
It is a kind of or at least two combination, for example, the combination of the combination of calcium oxide and calcium carbonate, calcium carbonate and calcium hydroxide, hydroxide
The combination of calcium and sodium carbonate or the combination of sodium carbonate and sodium oxide molybdena etc., but be not limited only to cited combination, in combination range its
His unlisted combination is equally applicable, preferably one kind of calcium oxide, calcium carbonate or calcium hydroxide or at least two combination.
Preferably, the time of step (3) described neutralisation treatment be 0.5-8h, such as 0.5h, 1h, 1.5h, 2h, 2.5h, 3h,
3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h or 8h etc., it is not limited to cited numerical value, the numerical value model
Other unlisted numerical value are equally applicable in enclosing, preferably 1-3h.
Preferably, the pH value of step (3) the removing toxic substances soil is 6-8, such as 6,6.5,7,7.5 or 8 etc., but simultaneously not only limit
Equally applicable, the preferably 6.5-7.5 in other unlisted numerical value in cited numerical value, the numberical range.
In the present invention, be separated by solid-liquid separation it is resulting it is filtered removing toxic substances soil in remain Cr VI reduction and neutralize principle with
Hexavalent chromium-treatments are identical in filtrate.
As currently preferred technical solution, step (4) biomass reductant be municipal sludge, rubbish from cooking or
In the composting production of feces of livestock and poultry any one or at least two combination, such as the compost and rubbish from cooking of municipal sludge
The combination of compost, the combination of compost of the compost and feces of livestock and poultry of rubbish from cooking or the heap of the compost of feces of livestock and poultry and municipal sludge
The combination etc. of fertilizer, but it is not limited only to cited combination, other unlisted combinations are equally applicable in combination range.
Preferably, the content of organic matter and institute in biomass reductant described in step (4) the biomass reduction operation
The ratio for stating Cr VI quality in removing toxic substances soil is 10:1-500:1, such as 10:1,50:1,100:1,150:1,200:1,250:
1,300:1,350:1,400:1,450:1 or 500:1 etc., it is not limited to cited numerical value, in the numberical range other
Unlisted numerical value is equally applicable, preferably 10:1-200:1；Wherein, have in the mixture of biomass reductant reconciliation pesticide-clay mixture earth
The final mass content of machine matter is 5% or more.
Preferably, the time of step (4) described biomass reduction be 2-360d, such as 2d, 5d, 10d, 15d, 20d, 25d,
30d, 40d, 50d, 80d, 100d, 120d, 150d, 180d, 200d, 250d, 300d or 360d etc., it is not limited to cited
Numerical value, other unlisted numerical value are equally applicable in the numberical range, preferably 7-180d.
Preferably, step (4) plant is Festuca Arundinacea, Bermuda grass, Conyza canadensis, emarginate amaranth herb or seed, chenopodium glaucum linn, herba eleusines indicae, Han
In dish or Amaranthus retroflexus any one or at least two combination, such as the combination of Festuca Arundinacea and wolf's fang root, Conyza canadensis and wild amaranth
The combination of Zu the He Huo indian rorippa herb and Amaranthus retroflexus of the combination of dish, chenopodium glaucum linn and herba eleusines indicae, but it is not limited only to cited combination, combination
Other unlisted combinations are equally applicable in range.
In the present invention, " brightness reversion " problem may occur after repairing chromium-polluted soil for electronation, it is long using biomass
Effect reduction and phytoremediation further restore stabilization.Compared to FeSO4Equal inorganic reductions medicament, biomass reductant include phenol hydroxyl
The groups such as base, hydroxyl, amino, carboxyl, sulfonic group, can be used as electron-donating group, provide reducing environment for Cr VI, the used time also has
There is certain adsorption capacity and can be a kind of green, stable, long-acting repair materials with reduction of hexavalent chromium ion, it can be effective
Ground carries out continued reduction to the residual acid soluble hexavalent chromium of slow release.Plant to a small amount of Cr VI remaining in soil carry out into
The transfer enrichment of one step to thoroughly solve the problems, such as " brightness reversion " after soil remediation, while being realized and using function to contaminated site
It can be with the recovery of ecological environment.
As currently preferred technical solution, the reduzate is sodium sulfite, potassium sulfite, sulfur dioxide, vulcanization
One of sodium or sulphur or at least two combination, such as the combination of sodium sulfite and potassium sulfite, potassium sulfite and dioxy
Change the combination of sulphur, the combination of sulfur dioxide and vulcanized sodium or vulcanized sodium and the combination of sulphur etc., but is not limited only to cited group
It closes, other unlisted combinations are equally applicable in combination range, preferably one of sulfur dioxide, vulcanized sodium or sulphur or extremely
Few two kinds of combination.
Preferably, theoretical amount needed for the additive amount of the reduzate is all restored with Cr VI in the processing extraction raffinate
Ratio is 1:1-8:1, such as 1:1,2:1,3:1,4:1,5:1,6:1,7:1 or 8:1 etc., it is not limited to cited number
Value, other interior unlisted numerical value of the numberical range are equally applicable, preferably 2:1-5:1.
As currently preferred technical solution, the initial pH value of the reduction treatment is 0.5-5, for example, 0.5,1,1.5,
2,2.5,3,3.5,4,4.5 or 5 etc., it is not limited to cited numerical value, other interior unlisted numerical value of the numberical range
It is equally applicable, preferably 2-4.
Preferably, the time of the reduction treatment be 10-120min, such as 10min, 20min, 30min, 40min,
50min, 60min, 70min, 80min, 90min, 100min, 110min or 120min etc., it is not limited to cited number
Value, other interior unlisted numerical value of the numberical range are equally applicable, preferably 20-40min.
As currently preferred technical solution, the precipitating reagent is sodium oxide molybdena, sodium hydroxide, calcium oxide, calcium hydroxide
One of sodium carbonate or at least two combination, such as the combination of sodium oxide molybdena and sodium hydroxide, sodium hydroxide and calcium oxide
Combination, the combination of calcium oxide and calcium hydroxide or calcium hydroxide and the combination of sodium carbonate etc., but be not limited only to cited group
It closes, other unlisted combinations are equally applicable in combination range, preferably one kind of sodium hydroxide or sodium carbonate or at least two
Combination.
Preferably, the initial pH value of the precipitating operation is 5.5-10, such as 5.5,6,6.5,7,7.5,8,8.5,9,9.5
Or 10 etc., it is not limited to cited numerical value, other interior unlisted numerical value of the numberical range are equally applicable, preferably 7-
9。
Preferably, the time of the precipitating operation is 10-60min, such as 10min, 20min, 30min, 40min, 50min
Or 60min etc., it is not limited to cited numerical value, other interior unlisted numerical value of the numberical range are equally applicable, preferably
For 20-40min.
Preferably, the filtrate of 50-95% returns and is used as step (1) described ore grinding solution in the filtrate, in the filtrate
Remaining filtrate, which returns, is used as step (2) described rework solution.
In the present invention, first by hexavalent chrome reduction in filtrate at trivalent chromic ion, then plus precipitating reagent adjust pH, make trivalent chromium
Chromium hydroxide precipitation is formed, reaction equation is as follows:
As currently preferred technical solution, the described method comprises the following steps:
(1) chromium-polluted soil of the 300-20000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain grain
Degree is the slurry of 20-200 mesh；Wherein, the granularity of chromium-polluted soil particle is 20-200 mesh, chromium in the slurry in the slurry
The content of contaminated soil is 10-90%；
(2) sulfuric acid and rework solution mixing that the slurry and concentration obtained step (1) is 50-98%, carry out acidification
0.5-12h obtains acidification slurry, is separated by solid-liquid separation, and obtains processing extraction raffinate and pre-processes soil；Wherein, the addition of sulfuric acid
Amount is with H2SO4Meter and the ratio of chromium-polluted soil quality in slurry are 0.01:1-0.8:1；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, under conditions of initial pH value is 0.5-5 into
Neutralizer is added later and is neutralized 0.5-8h, obtains the removing toxic substances soil that pH value is 6-8 by row reduction treatment 0.5-24h；Its
In, the reducing agent be one of ferrous sulfate, vulcanized sodium, calcium sulfide, sulfur dioxide, sodium thiosulfate or sodium sulfite or
One of at least two combination, preferably ferrous sulfate, vulcanized sodium or calcium sulfide or at least two combination；The reduction
The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 1:1-8:1 in the additive amount and pretreatment soil of agent；The neutralizer is
One of calcium oxide, calcium carbonate, calcium hydroxide, sodium carbonate or sodium hydroxide or at least two combination, preferably calcium oxide,
One kind of calcium carbonate or calcium hydroxide or at least two combination；
(4) the removing toxic substances Soil Utilization biomass reductant for obtaining step (3) carries out biomass reduction operation 2-360d simultaneously
Planting plants are repaired；Wherein, the biomass reductant is the composting production of municipal sludge, rubbish from cooking or feces of livestock and poultry
In any one or at least two combination；In the biomass reduction in biomass reductant organic matter content and removing toxic substances
The ratio of Cr VI quality is 10:1-500:1 in soil；The plant is Festuca Arundinacea, Bermuda grass, Conyza canadensis, emarginate amaranth herb or seed, grayish green
In Chenopodiaceae, herba eleusines indicae, indian rorippa herb or Amaranthus retroflexus any one or at least two combination；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), initial pH value be 0.5-5 under conditions of into
Precipitating reagent is added later and carries out precipitating operation 10- under conditions of initial pH value is 5.5-10 by row reduction operation 10-120min
60min obtains filtrate and filter cake containing chromium through being separated by solid-liquid separation, and filtrate return step (1) is used as ore grinding solution and step (2) and returns
Liquid is returned, filter cake containing chromium carries out resource and changes utilization；Wherein, the reducing agent is sodium sulfite, potassium sulfite, sulfur dioxide, vulcanization
One of sodium or sulphur or at least two combination, preferably one of sulfur dioxide, vulcanized sodium or sulphur or at least two
The combination of kind；The ratio of theoretical amount needed for Cr VI all restores in the additive amount and processing extraction raffinate of the reducing agent is 1:1-
8:1；The precipitating reagent is the group of one of sodium oxide molybdena, sodium hydroxide, calcium oxide, calcium hydroxide or sodium carbonate or at least two
Close, preferably one kind of sodium hydroxide or sodium carbonate or at least two combination.
Compared with prior art, the invention has the following advantages:
(1) the long-acting reduction COMBINED PROCESS that Cr VI is remained in the separation and recovery of Cr VI and soil solves pollution of chromium
" brightness reversion " problem after soil remediation；
(2) Cr VI and soil are effectively separated, and carry out Resource recovery, create economic benefit；
(3) filtrate cycle uses, and resource utilization can be improved and reduce rehabilitation cost；
(4) by biomass and phytoremediation, long-acting reduction of hexavalent chromium is not only realized, but also also achieve contaminated site
Ecological recovery.
Detailed description of the invention
Fig. 1 is a kind of method and process flow chart of chromium-polluted soil reparation provided by the invention.
The present invention is described in more detail below.But following examples is only simple example of the invention, not generation
Table or limitation the scope of the present invention, protection scope of the present invention are subject to claims.
Specific embodiment
To further illustrate the technical scheme of the present invention below with reference to the accompanying drawings and specific embodiments.
As shown in Figure 1, the method and process process of chromium-polluted soil reparation provided by the invention are as follows: first by chromium-polluted soil
It is mixed with ore grinding solution and carries out ore grinding processing, slurry is obtained after the completion of ore grinding；Then obtained slurry and rework solution are mixed
Merge and sulfuric acid progress acidification is added, after the completion of acidification, obtain acidification slurry, be separated by solid-liquid separation, obtains processing extraction raffinate
With pretreatment soil；Then resulting pretreatment soil and reducing agent are mixed and are carried out reduction treatment, reduction adds after completing
Enter neutralizer to be neutralized, removing toxic substances soil is obtained after the completion of neutralisation treatment；Finally, using biomass reductant to obtaining
Removing toxic substances soil carries out biomass reduction operation and planting plants are repaired；Wherein, through being separated by solid-liquid separation obtained processing after acidification
Reduzate progress reduction treatment is added in extraction raffinate, precipitating reagent is added after the completion of reduction and carries out precipitating operation, precipitating passes through solid after terminating
The isolated filtrate of liquid and filter cake containing chromium, filtrate, which returns, is used as ore grinding solution and rework solution, and filter cake containing chromium carries out resource and changes utilization.
In order to better illustrate the present invention, it is easy to understand technical solution of the present invention, of the invention is typical but non-limiting
Embodiment is as follows:
Embodiment 1
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 8000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain slurry；Its
In, the granularity of chromium-polluted soil particle is 160 mesh in the slurry, and the content of chromium-polluted soil is 50% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 80%, carry out acidification 2h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.2:1；Wherein, in soil 99.2% acid soluble hexavalent chromium and water solubility
Cr VI is discharged into slurry, and 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 3
12h is managed in original place, and neutralizer is added later and is neutralized 2h, obtains the removing toxic substances soil that pH value is 7；Wherein, the reducing agent
For ferrous sulfate；The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 2 in the additive amount and pretreatment soil of the reducing agent:
1；The neutralizer is sodium hydroxide, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but examines again after 30 days
When survey, content of 6-valence Cr ions is about 80mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 15d and planted
Plant is repaired；Wherein, the biomass reductant is the composting production of cow dung；Biomass reduction in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 80:1 in agent；The plant is Bermuda grass, plantation
Bermuda grass phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is gone back under conditions of initial pH value is 3
30min is managed in original place, and precipitating reagent is added later and carries out precipitating operation 30min under conditions of initial pH value is 8, through being separated by solid-liquid separation
To filtrate and filter cake containing chromium, filtrate return step (1) is used as rework solution as ore grinding solution and step (2), and filter cake containing chromium carries out
Resource changes utilization；Wherein, the reduzate is sodium sulfite；Cr VI is whole in the additive amount and processing extraction raffinate of the reduzate
The ratio of theoretical amount needed for restoring is 2:1；The precipitating reagent is sodium hydroxide, and the content of Cr VI is lower than 0.5mg/ in filtrate
L, 50% filtrate, which returns, in the filtrate is used as ore grinding solution, and 50% filtrate, which returns, in the filtrate is used as rework solution.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 2mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Embodiment 2
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 16000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain slurry；Its
In, the granularity of chromium-polluted soil particle is 200 mesh in the slurry, and the content of chromium-polluted soil is 60% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 95%, carry out acidification 2h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.3:1；Wherein, in soil 99.3% acid soluble hexavalent chromium and water solubility
Cr VI is discharged into slurry, and 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 3
12h is managed in original place, and neutralizer is added later and is neutralized 2h, obtains the removing toxic substances soil that pH value is 7；Wherein, the reducing agent
For ferrous sulfate；The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 2 in the additive amount and pretreatment soil of the reducing agent:
1；The neutralizer is calcium carbonate, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but detects again after 30 days
When, content of 6-valence Cr ions is about 100mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 20d and planted
Plant is repaired；Wherein, the biomass reductant is the composting production of chicken manure；Biomass reduction in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 100:1 in agent；The plant is Bermuda grass, plantation
Bermuda grass phytoremediation 80d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is carried out under conditions of initial pH value is 2.5
Reduction treatment 30min is added precipitating reagent and carries out precipitating operation 30min under conditions of initial pH value is 8, later through being separated by solid-liquid separation
Obtain filtrate and filter cake containing chromium, filtrate return step (1) is used as rework solution as ore grinding solution and step (2), filter cake containing chromium into
Row resource changes utilization；Wherein, the reduzate is sulfur dioxide；The additive amount of the reduzate and Cr VI in processing extraction raffinate are complete
The ratio of theoretical amount needed for portion restores is 4:1；The precipitating reagent is sodium hydroxide, and the content of Cr VI is lower than in filtrate
0.5mg/L, 60% filtrate, which returns, in the filtrate is used as ore grinding solution, and 40% filtrate returns as returning in the filtrate
Liquid.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 3mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Embodiment 3
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 5000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain slurry；Its
In, the granularity of chromium-polluted soil particle is 120 mesh in the slurry, and the content of chromium-polluted soil is 50% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 80%, carry out acidification 2h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.15:1；Wherein, 99.1% acid soluble hexavalent chromium and water-soluble in soil
Property Cr VI be discharged into slurry, 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 3
12h is managed in original place, and neutralizer is added later and is neutralized 2h, obtains the removing toxic substances soil that pH value is 7；Wherein, the reducing agent
For calcium sulfide；The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 3:1 in the additive amount and pretreatment soil of the reducing agent；
The neutralizer is calcium oxide, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but detects again after 30 days
When, content of 6-valence Cr ions is about 70mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 15d and planted
Plant is repaired；Wherein, the biomass reductant is the composting production of sheep dung；Biomass reduction in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 80:1 in agent；The plant is Bermuda grass, plantation
Bermuda grass phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is gone back under conditions of initial pH value is 3
30min is managed in original place, and precipitating reagent is added later and carries out precipitating operation 30min under conditions of initial pH value is 8, through being separated by solid-liquid separation
To filtrate and filter cake containing chromium, filtrate return step (1) is used as rework solution as ore grinding solution and step (2), and filter cake containing chromium carries out
Resource changes utilization；Wherein, the reduzate is vulcanized sodium；Cr VI is all gone back in the additive amount and processing extraction raffinate of the reducing agent
The ratio of theoretical amount needed for original is 3:1；The precipitating reagent is sodium hydroxide, and the content of Cr VI is lower than 0.5mg/L in filtrate,
95% filtrate, which returns, in the filtrate is used as ore grinding solution, and 5% filtrate, which returns, in the filtrate is used as rework solution.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 2.5mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Embodiment 4
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 10000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain slurry；Its
In, the granularity of chromium-polluted soil particle is 160 mesh in the slurry, and the content of chromium-polluted soil is 50% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 85%, carry out acidification 2h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.25:1；Wherein, 99.2% acid soluble hexavalent chromium and water-soluble in soil
Property Cr VI be discharged into slurry, 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 3
12h is managed in original place, and neutralizer is added later and is neutralized 2h, obtains the removing toxic substances soil that pH value is 7；Wherein, the reducing agent
For ferrous sulfate；The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 3 in the additive amount and pretreatment soil of the reducing agent:
1；The neutralizer is calcium oxide, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but detects again after 30 days
When, content of 6-valence Cr ions is about 60mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 18d and planted
Plant is repaired；Wherein, the biomass reductant is the composting production of cow dung；Biomass reduction in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 120:1 in agent；The plant is Bermuda grass, plantation
Bermuda grass phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2) and carries out reduction treatment under conditions of pH value is 3
Precipitating reagent is added later and carries out precipitating operation 30min under conditions of pH value is 8, is separated by solid-liquid separation and obtains filtrate and contain by 30min
Chromium filter cake, filtrate return step (1) are used as rework solution as ore grinding solution and step (2), and filter cake containing chromium carries out resource and changes utilization；
Wherein, the reduzate is sulphur；Theoretical amount needed for Cr VI all restores in the additive amount and processing extraction raffinate of the reduzate
Ratio be 3:1；The precipitating reagent is sodium hydroxide, and the content of Cr VI is lower than 0.5mg/L in filtrate, in the filtrate
80% filtrate, which returns, is used as ore grinding solution, and 20% filtrate, which returns, in the filtrate is used as rework solution.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 1.5mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Embodiment 5
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 20000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain slurry；Its
In, it is 50% that the granularity of chromium-polluted soil particle, which is the content of chromium-polluted soil in slurry described in 200 mesh, in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 98%, carry out acidification 2h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.35:1；Wherein, 99.2% acid soluble hexavalent chromium and water-soluble in soil
Property Cr VI be discharged into slurry, 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 3
12h is managed in original place, and neutralizer is added later and is neutralized 2h, obtains the removing toxic substances soil that pH value is 7；Wherein, the reducing agent
For ferrous sulfate；The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 5 in the additive amount and pretreatment soil of the reducing agent:
1；The neutralizer is calcium hydroxide, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but examines again after 30 days
When survey, content of 6-valence Cr ions is about 120mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 20d and planted
Plant is repaired；Wherein, the biomass reductant is the composting production of chicken manure；Biomass reduction in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 150:1 in agent；The plant is Bermuda grass, plantation
Bermuda grass phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2) in (3), carries out under conditions of initial pH value is 3
Reduction treatment 30min is added precipitating reagent and carries out precipitating operation 30min under conditions of initial pH value is 8, later through being separated by solid-liquid separation
Obtain filtrate and filter cake containing chromium, filtrate return step (1) is used as rework solution as ore grinding solution and step (2), filter cake containing chromium into
Row resource changes utilization；Wherein, the reduzate is sodium sulfite；The additive amount of the reduzate and Cr VI in processing extraction raffinate are complete
The ratio of theoretical amount needed for portion restores is 3:1；The precipitating reagent is sodium hydroxide, and the content of Cr VI is lower than in filtrate
0.5mg/L, 70% filtrate, which returns, in the filtrate is used as ore grinding solution, and 30% filtrate returns as returning in the filtrate
Liquid.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 3mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Comparative example 1
Without being separated by solid-liquid separation after sulfuric acid acidification, all Cr VIs all stay carries out subsequent electronation in the soil
Outside, remaining is same as Example 5.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 60mg/kg in soil after reparation, there is " brightness reversion " phenomenon.
Comparative example 2
In addition to not using biomass and long-effect plant to restore, remaining is same as Example 5.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 80mg/kg in soil after reparation, there is " brightness reversion " phenomenon.
Embodiment 6
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 300mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtaining granularity is 20
Purpose slurry；Wherein, the content of chromium-polluted soil is 90% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 50%, carry out acidification
0.5h obtains acidification slurry, is separated by solid-liquid separation, and obtains processing extraction raffinate and pre-processes soil；Wherein, the additional amount of sulfuric acid with
H2SO4Meter and the ratio of chromium-polluted soil quality in slurry are 0.01:1；Wherein, in soil 99.2% acid soluble hexavalent chromium and
Water soluble hexavalent chromium is discharged into slurry, and 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is carried out under conditions of initial pH value is 0.5
Neutralizer is added later and is neutralized 0.5h, obtains the removing toxic substances soil that pH value is 6 by reduction treatment 0.5h；Wherein, described to go back
Former agent is sodium thiosulfate；The ratio of theoretical amount needed for remaining hexavalent chrome reduction in the additive amount and pretreatment soil of the reducing agent
Value is 8:1；The neutralizer is sodium carbonate, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but the weight after 30 days
When new detection, content of 6-valence Cr ions is about 120mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 2d and planted
Plant is repaired；Wherein, the biomass reductant is the composting production of aerobic sludge；Biomass in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 350:1 in reducing agent；The plant is emarginate amaranth herb or seed,
Plant emarginate amaranth herb or seed phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is carried out under conditions of initial pH value is 0.5
Reduction treatment 80min is added precipitating reagent and carries out precipitating operation 10min under conditions of initial pH value is 6, later through being separated by solid-liquid separation
Obtain filtrate and filter cake containing chromium, filtrate return step (1) is used as rework solution as ore grinding solution and step (2), filter cake containing chromium into
Row resource changes utilization；Wherein, the reduzate is sodium sulfite；The additive amount of the reduzate and Cr VI in processing extraction raffinate are complete
The ratio of theoretical amount needed for portion restores is 8:1；The precipitating reagent is calcium hydroxide, and the content of Cr VI is lower than in filtrate
0.5mg/L, 55% filtrate, which returns, in the filtrate is used as ore grinding solution, and 45% filtrate returns as returning in the filtrate
Liquid.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 3mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Embodiment 7
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 1000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtaining granularity is 80
Purpose slurry；Wherein, the content of chromium-polluted soil is 10% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 50%, carry out acidification 6h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.8:1；Wherein, in soil 99.2% acid soluble hexavalent chromium and water solubility
Cr VI is discharged into slurry, and 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 5
Original place is managed for 24 hours, and neutralizer is added later and is neutralized 8h, obtains the removing toxic substances soil that pH value is 6.5；Wherein, the reduction
Agent is vulcanized sodium；The ratio of theoretical amount needed for remaining hexavalent chrome reduction is 5 in the additive amount and pretreatment soil of the reducing agent:
1；The neutralizer is calcium hydroxide, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but examines again after 30 days
When survey, content of 6-valence Cr ions is about 120mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 120d and planted
Plant is planted to be repaired；Wherein, the biomass reductant is the composting production of cow dung；Biomass is also in the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 10:1 in former agent；The plant is herba eleusines indicae, kind
Plant herba eleusines indicae phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is gone back under conditions of initial pH value is 6
10min is managed in original place, and precipitating reagent is added later and carries out precipitating operation 60min under conditions of initial pH value is 10, through being separated by solid-liquid separation
Obtain filtrate and filter cake containing chromium, filtrate return step (1) is used as rework solution as ore grinding solution and step (2), filter cake containing chromium into
Row resource changes utilization；Wherein, the reduzate is potassium sulfite；The additive amount of the reduzate and Cr VI in processing extraction raffinate are complete
The ratio of theoretical amount needed for portion restores is 6:1；The precipitating reagent is sodium carbonate, and the content of Cr VI is lower than 0.5mg/ in filtrate
L, 65% filtrate, which returns, in the filtrate is used as ore grinding solution, and 35% filtrate, which returns, in the filtrate is used as rework solution.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 3mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Embodiment 8
The present invention provides a kind of this methods of chromium-polluted soil reparation, the described method comprises the following steps:
(1) chromium-polluted soil of the 3000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtaining granularity is 60
Purpose slurry；Wherein, the content of chromium-polluted soil is 30% in the slurry；
(2) sulfuric acid and the rework solution mixing that the slurry and concentration obtained step (1) is 55%, carry out acidification 12h,
Acidification slurry is obtained, is separated by solid-liquid separation, processing extraction raffinate is obtained and pre-processes soil；Wherein, the additional amount of sulfuric acid is with H2SO4
Meter and the ratio of chromium-polluted soil quality in slurry are 0.04:1；Wherein, 99.2% acid soluble hexavalent chromium and water-soluble in soil
Property Cr VI be discharged into slurry, 90% Cr VI enters filtrate in soil, and 10% Cr VI residual is in the soil；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is carried out under conditions of initial pH value is 4.5
Neutralizer is added later and is neutralized 5h, obtains the removing toxic substances soil that pH value is 6.5 by reduction treatment 7h；Wherein, the reduction
Agent is sulfur dioxide；The additive amount of the reducing agent and the ratio of theoretical amount needed for remaining hexavalent chrome reduction in pretreatment soil are
1:1；The neutralizer is sodium hydroxide, detects content of 6-valence Cr ions in soil at that time and is lower than 30mg/kg, but after 30 days again
When detection, content of 6-valence Cr ions is about 120mg/kg in soil；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 360d and planted
Plant is planted to be repaired；Wherein, the biomass reductant is the composting production of mineralising house refuse；In the biomass reduction
The content of organic matter and the ratio of Cr VI quality in the removing toxic substances soil are 500:1 in biomass reductant；The plant is
Amaranthus retroflexus plants Amaranthus retroflexus phytoremediation 60d；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is carried out under conditions of initial pH value is 4.5
Reduction treatment 120min is added precipitating reagent and carries out precipitating operation 45min under conditions of initial pH value is 6.5, later through solid-liquid
Isolated filtrate and filter cake containing chromium, filtrate return step (1) are used as rework solution as ore grinding solution and step (2), filter containing chromium
Cake carries out resource and changes utilization；Wherein, the reduzate is potassium sulfite；Sexavalence in the additive amount and processing extraction raffinate of the reduzate
The ratio of theoretical amount needed for chromium all restores is 1:1；The precipitating reagent is sodium oxide molybdena, and the content of Cr VI is lower than in filtrate
0.5mg/L, 80% filtrate, which returns, in the filtrate is used as ore grinding solution, and 20% filtrate returns as returning in the filtrate
Liquid.
The total amount of Cr VI in after regular sampling analysis soil remediation.
Testing result is shown: the total amount of Cr VI is 3mg/kg in soil after reparation, always without " brightness reversion " phenomenon.
Based on the above embodiments with the result of comparative example it is found that the present invention is separated by the middle Cr VI to chromium-polluted soil
And solve the problems, such as " brightness reversion " after chromium-polluted soil reparation by the long-acting reduction group technology of biomass and plant, while
Also achieve contaminated site ecological recovery.
The preferred embodiment of the present invention has been described above in detail, still, during present invention is not limited to the embodiments described above
Detail within the scope of the technical concept of the present invention can be with various simple variants of the technical solution of the present invention are made, this
A little simple variants all belong to the scope of protection of the present invention.
It is further to note that specific technical features described in the above specific embodiments, in not lance
In the case where shield, can be combined in any appropriate way, in order to avoid unnecessary repetition, the present invention to it is various can
No further explanation will be given for the combination of energy.
In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally
The thought of invention, it should also be regarded as the disclosure of the present invention.
Claims (10)
1. a kind of method of chromium-polluted soil reparation, which is characterized in that the described method comprises the following steps:
(1) chromium-polluted soil and ore grinding solution are mixed and carries out ore grinding processing, obtain slurry；
(2) slurry and sulfuric acid and the rework solution mixing obtained step (1) carries out acidification, obtains acidification slurry, passes through
It is separated by solid-liquid separation, obtains processing extraction raffinate and pre-processes soil；
(3) reduction treatment is carried out to the resulting pretreatment soil of step (2) and reducing agent mixing, is added in neutralizer progress later
And processing, obtain removing toxic substances soil；
(4) the removing toxic substances Soil Utilization biomass reductant for obtaining step (3) carries out biomass reduction operation, then planting plants
It is repaired；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2) and carries out reduction treatment, precipitating reagent is added later and is sunk
Shallow lake operation obtains filtrate and filter cake containing chromium through being separated by solid-liquid separation, and filtrate distinguishes return step (1) and is used as ore grinding solution and step (2)
As rework solution, filter cake containing chromium carries out resource utilization.
2. the method as described in claim 1, which is characterized in that the content of Cr VI is in step (1) described chromium-polluted soil
300-20000mg/kg, preferably 5000-20000mg/kg.
3. method according to claim 1 or 2, which is characterized in that step (1) ore grinding is wet-milling；
Preferably, the granularity of chromium-polluted soil particle is 20-200 mesh, preferably 50-200 mesh in step (1) described slurry；
Preferably, the content of chromium-polluted soil described in step (1) described slurry is 10-90%, preferably 20-70%.
4. the method according to claim 1, which is characterized in that the concentration of step (2) described sulfuric acid is 50-
98%, preferably 80-98%；
Preferably, the additional amount of step (2) described sulfuric acid is with H2SO4The ratio of chromium-polluted soil quality described in meter and the slurry
Value is 0.01:1-0.8:1, preferably 0.1:1-0.5:1；
Preferably, the time of step (2) described acidification is 0.5-12h, preferably 1-6h.
5. method according to any of claims 1-4, which is characterized in that step (3) reducing agent is ferrous sulfate, sulphur
Change the combination of one of sodium, calcium sulfide, sulfur dioxide, sodium thiosulfate or sodium sulfite or at least two, preferably sulfuric acid
One of ferrous, vulcanized sodium or calcium sulfide or at least two combination；
Preferably, the additive amount of step (3) described reducing agent and theory needed for hexavalent chrome reduction remaining in the pretreatment soil
The ratio of amount is 1:1-8:1, preferably 2:1-4:1；
Preferably, the initial pH value of step (3) described reduction treatment is 0.5-5, preferably 1-4；
Preferably, the time of step (3) described reduction treatment is 0.5-24h, preferably 6-18h；
Preferably, step (3) neutralizer is one of calcium oxide, calcium carbonate, calcium hydroxide, sodium carbonate or sodium hydroxide
Or at least two combination, preferably one kind of calcium oxide, calcium carbonate or calcium hydroxide or at least two combination；
Preferably, the time of step (3) described neutralisation treatment is 0.5-8h, preferably 1-3h；
Preferably, the pH value of step (3) the removing toxic substances soil is 6-8, preferably 6.5-7.5.
6. the method according to claim 1 to 5, which is characterized in that step (4) biomass reductant is city
In the composting production of sludge, rubbish from cooking or feces of livestock and poultry any one or at least two combination；
Preferably, in biomass reductant described in step (4) the biomass reduction operation organic matter content Yu the solution
The ratio of Cr VI quality is 10:1-500:1, preferably 10:1-200:1 in pesticide-clay mixture earth；
Preferably, the time of step (4) described biomass reduction is 2-360d, preferably 7-180d；
Preferably, step (4) plant be Festuca Arundinacea, Bermuda grass, Conyza canadensis, emarginate amaranth herb or seed, chenopodium glaucum linn, herba eleusines indicae, indian rorippa herb or
In Amaranthus retroflexus any one or at least two combination.
7. as the method according to claim 1 to 6, which is characterized in that the reduzate be sodium sulfite, potassium sulfite,
One of sulfur dioxide, vulcanized sodium or sulphur or at least two combination, preferably in sulfur dioxide, vulcanized sodium or sulphur
It is a kind of or at least two combination；
Preferably, the additive amount of the reduzate and the ratio for handling Cr VI in extraction raffinate and all restoring required theoretical amount
For 1:1-8:1, preferably 2:1-5:1.
8. the method according to claim 1 to 7, which is characterized in that the initial pH value of the reduction treatment is 0.5-5,
Preferably 2-4；
It is preferred that bottom, the time of the reduction treatment is 10-120min, preferably 20-40min.
9. the method according to claim 1, which is characterized in that the precipitating reagent is sodium oxide molybdena, sodium hydroxide, oxygen
Change the combination of one of calcium, calcium hydroxide or sodium carbonate or at least two, preferably one kind of sodium hydroxide or sodium carbonate or
At least two combination；
Preferably, the initial pH value of the precipitating operation is 5.5-10, preferably 7-9；
Preferably, the time of the precipitating operation is 10-60min, preferably 20-40min；
Preferably, the filtrate of 50-95% returns and is used as step (1) described ore grinding solution in the filtrate, remaining in the filtrate
Filtrate return be used as step (2) described rework solution.
10. such as the described in any item methods of claim 1-9, which is characterized in that the described method comprises the following steps:
(1) chromium-polluted soil of the 300-20000mg/kg containing Cr VI and ore grinding solution are subjected to wet ground, obtain slurry；Its
In, the granularity of chromium-polluted soil particle is 20-200 mesh in the slurry, and the content of chromium-polluted soil is 10- in the slurry
90%；
(2) sulfuric acid and rework solution mixing that the slurry and concentration obtained step (1) is 50-98%, carry out acidification 0.5-
12h obtains acidification slurry, is separated by solid-liquid separation, and obtains processing extraction raffinate and pre-processes soil；Wherein, the additional amount of sulfuric acid with
H2SO4Meter and the ratio of chromium-polluted soil quality in slurry are 0.01:1-0.8:1；
(3) the resulting pretreatment soil of step (2) and reducing agent are mixed, is gone back under conditions of initial pH value is 0.5-5
0.5-24h is managed in original place, and neutralizer is added later and is neutralized 0.5-8h, obtains the removing toxic substances soil that pH value is 6-8；Wherein,
The reducing agent is for one of ferrous sulfate, vulcanized sodium, calcium sulfide, sulfur dioxide, sodium thiosulfate or sodium sulfite or extremely
Few two kinds of combination, preferably one of ferrous sulfate, vulcanized sodium or calcium sulfide or at least two combination；The reducing agent
Additive amount and the pretreatment soil in the ratio of theoretical amount needed for remaining hexavalent chrome reduction be 1:1-8:1；The neutralizer
For one of calcium oxide, calcium carbonate, calcium hydroxide, sodium carbonate or sodium hydroxide or at least two combination, preferably aoxidize
Calcium, one kind of calcium carbonate or calcium hydroxide or at least two combination；
(4) the removing toxic substances Soil Utilization biomass reductant that step (3) obtains is subjected to biomass reduction operation 2-360d and planted
Plant is repaired；Wherein, the biomass reductant is in the composting production of municipal sludge, rubbish from cooking or feces of livestock and poultry
Any one or at least two combination；In the biomass reduction in biomass reductant the content of organic matter and removing toxic substances soil
The ratio of middle Cr VI quality is 10:1-500:1；The plant be Festuca Arundinacea, Bermuda grass, Conyza canadensis, emarginate amaranth herb or seed, chenopodium glaucum linn,
In herba eleusines indicae, indian rorippa herb or Amaranthus retroflexus any one or at least two combination；
Wherein, reduzate is added in the resulting processing extraction raffinate of step (2), is gone back under conditions of initial pH value is 0.5-5
10-120min is managed in original place, and precipitating reagent is added later and carries out precipitating operation 10-60min under conditions of initial pH value is 5.5-10,
Filtrate and filter cake containing chromium are obtained through being separated by solid-liquid separation, the filtrate of 50-95% returns molten as step (1) described ore grinding in the filtrate
Liquid, remaining filtrate, which returns, in the filtrate is used as step (2) described rework solution, and filter cake containing chromium carries out resource and changes utilization；Wherein,
The reducing agent is the combination of one of sodium sulfite, potassium sulfite, sulfur dioxide, vulcanized sodium or sulphur or at least two,
Preferably one of sulfur dioxide, vulcanized sodium or sulphur or at least two combination；The additive amount of the reducing agent and processing
The ratio of theoretical amount needed for Cr VI all restores in extraction raffinate is 1:1-8:1；The precipitating reagent be sodium oxide molybdena, sodium hydroxide,
One of calcium oxide, calcium hydroxide or sodium carbonate or at least two combination, preferably one kind of sodium hydroxide or sodium carbonate
Or at least two combination.
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| CN116174464A (en) * | 2023-03-06 | 2023-05-30 | 核工业北京化工冶金研究院 | Secondary restoration stable solidification method for 'yellowing' chromium-polluted soil |
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