Background technology
The chromium slag that China's chromium salt factory is discharged in early days is deposited in the slag field without " four prevent " (antiseepage, flood control, anti-rain, anti-ly to fly upward) mostly, effectively do not disposed for many years and strict control, the chromium slag dust of weathering disperses with the wind and is settled down to neighbouring ground, water soluble hexavalent chromium is with surface water cross flow and infiltrate soil and underground water, causes the severe contamination of soil and underground water.Acid-soluble Cr VI simultaneously in chromium slag is under rainwater and carbon dioxide long term, also water soluble hexavalent chromium will be transferred to slowly, can say that chromium slag muck deposits place inherently huge pollution sources, constitute a serious threat to around human health and Environmental security, therefore removing acid-soluble state Cr VI in containing chromium slag contaminated soil is the key of soil restoring technology.
China started to carry out a series of research work to technology of repairing chromium contaminated soil in late 1990s, at present existing many sections of public technology bibliographical informations.In the prior art disclosed, the utility model patent of " chromium-polluted soil two-stage countercurrent washing medicament addition stabilization combined restoration method " (publication number: CN 101708501A) adopts two-stage washing equipment to wash chromium-polluted soil, because the method is only washed with clear water, so only better to state chromium clean result water-soluble in contaminated soil, when being applied to containing chromium slag contaminated soil remediation, the chromium of acid-soluble state and other forms is difficult to leach out, and clear water washing causes ferrous sulfate dosage in the method to be 15 ~ 30 times of theoretical dosage, dosage is larger, repairing effect is difficult to ensure.Cr VI acid-soluble in chromium-polluted soil is reduced adding acid medicine in the slip after chromium slag contaminated soil grinding with reduction medicament in utility model patent " a kind of method and apparatus for chromium slag contaminated soil Detoxified treatment " (publication number: CN 103071670A), but this patent cannot ensure that the trivalent chromium after reducing is in alkali condition, need to investigate to the effect of chromic stabilisation; Utility model patent " thermal decomposition repairing method containing chromium soil " (application number: mention a kind of containing chromium soil thermal decomposition repairing method 200810035563.9), this technology needs adiabatic pyrolysis 1 hour at 800 DEG C, therefore very high to the requirement of equipment, and energy consumption and processing cost are also very high, not easily carry out large-scale application.
Chromium salt factory is mixed with the mechanical mixture soil such as chromium slag, sand and building waste, this type of soil, because being mixed with chromium slag, except containing except water-soluble state Cr VI, also contains a large amount of acid-soluble Cr VI that chromium slag brings, therefore hexavalent chromium concentration is very high, is difficult to utilize conventional, traditional soil restoring technology to be administered.
The utility model is intended to overcome the deficiencies in the prior art, provides a kind of for high chromium concentration contaminated soil remediation system adopting recirculating, acidulant, reducing agent and stabilizing and curing agent is added chromium-polluted soil to eliminate its toxicity, soil can normally be utilized.Environmental capacity index limits when total chromium content in soil and chromic leaching concentration are used as roadbed material and aggregate lower than chromium slag in " chromium slag contaminated Environment control resist technology specification " (provisional) (HJ/T 301-2007) after removing toxic substances; i.e. Cr6+≤0.5mg/L; total chromium≤1.5mg/L; reduction is stablized rate and is reached more than 99%, and after process, soil has long-time stability.This technological operation is easy, cost is low, mechanization degree is high, efficiently fast, and non-secondary pollution, there are good market prospects.
Summary of the invention
The technical problems to be solved in the utility model is to provide a kind of detachable adjustment, is easy to carrying, and can carries out independent adjustment according to place concrete condition, can continuously, effective process chromium-polluted soil of fully automatic operation the repair system of non-secondary pollution.
For reaching above-mentioned purpose, a kind of modular of the utility model optimizes integrated-type high chromium concentration contaminated soil remediation system adopting recirculating, described repair system comprises feeding module, Mechanical Crushing module, medicament preparation module, reaction module, Separation of Solid and Liquid module and recirculated water module, described feeding module leads to described Mechanical Crushing module, described Mechanical Crushing module and described medicament configuration module lead to described reaction module respectively, described reaction module leads to described Separation of Solid and Liquid module, described Separation of Solid and Liquid module comprises discharging opening and liquid outlet, described Separation of Solid and Liquid module liquid outlet leads to described recirculated water module, described recirculated water module leads to described Mechanical Crushing module and described medicament configuration module respectively.
Wherein said medicament configuration module comprises sour dispensing system, reducing agent dispensing system and stabilizing and curing agent dispensing system, described sour dispensing system, described reducing agent dispensing system and described stabilizing and curing agent dispensing system lead to described reaction module respectively, and described recirculated water module leads to described sour dispensing system, described reducing agent dispensing system and described stabilizing and curing agent dispensing system respectively.
Wherein said feeding module comprises mechanical feeder, vibratory sieve and belt conveyor, described Mechanical Crushing module comprises ball mill and slurry storage tank, described sour dispensing system comprises sour storage tank, sour dispensing canister, the first acid-proof pump and acid solution metering device, described reducing agent dispensing system comprises reducing agent storage tank, reducing agent dispensing canister, the second acid-proof pump and reductant metering device, described stabilizing and curing agent dispensing system comprises powder frequency conversion batcher, conveying worm, stirring and dissolving tank and is furnished with the screw pump of metering device, described reaction module comprises acidproof slush pump, anticorrosion retort, motor reducer and anticorrosion paddle, described Separation of Solid and Liquid module comprises Pneumatic mud pump, plate and frame filter press and blowpit, described recirculated water module comprises liquid storage tank and water pump, described hanging vibratory sieve is installed in described mechanical feeder bottom, described hanging vibratory sieve discharge end connects the afterbody of described belt conveyor, the head of described belt conveyor is connected with the head inlet of described ball mill, the afterbody port of export of described ball mill connects described slurry storage tank, described slurry storage tank is connected with described anticorrosion retort by described acidproof slush pump, in described anticorrosion retort, top is described motor reducer, described motor reducer connects the described anticorrosion paddle below it, described sour storage tank connects described sour dispensing canister, described sour dispensing canister connects described anticorrosion retort by described first acid-proof pump and described acid solution flowermeter successively, described reducing agent storage tank connects described reducing agent dispensing canister, described reducing agent dispensing canister connects described anticorrosion retort by described second acid-proof pump and described reductant metering device successively, described powder frequency conversion batcher is successively by described conveying worm, described stirring and dissolving pump, the described screw pump being furnished with metering device connects described anticorrosion retort, described anticorrosion retort is connected with described plate and frame filter press by Pneumatic mud pump, it is described blowpit below described plate and frame filter press, top connects described liquid storage tank, described liquid storage tank by water pump respectively with described sour dispensing canister, described reducing agent dispensing canister, described stirring and dissolving tank and described ball mill are connected.
Wherein said vibratory sieve is hanging vibratory sieve.
The wherein said higher side of hanging vibratory sieve is provided with vibrations motor, and surrounding has support spring.
Wherein said ball mill is overflow ball mill.
Wherein said overflow ball mill comprises rotating cylinder and motor gear reducer, described rotating cylinder is provided with revolution gear wheel, studs with anticorrosion antiwear liner plate in cylindrical shell; The gear reduction unit of described motor gear reducer is provided with can pinion, the bull gear of drive ball grinding machine; The inner surface of cylindrical shell hollow journal bush is equipped with anticorrosion backpitch blade, and can return in described ball mill by the bead overflowed in ore pulp and rough piece, material freely overflows through the hollow axle journal of exhaust end.
Wherein said stirring and dissolving tank is stainless steel stirring and dissolving tank.
Wherein said plate and frame filter press adopts diaphragm pressing technology, and two-way squeezing filter cake, can make filter cake fully dewater.Be provided with filter cloth between pressing plate, blowpit is in below pressing plate, and pressing plate is fixed by the mechanical plate thick stick being located at pressure filter rack both sides.
The utility model system is divided into multiple module, directly can freely connect between module, and individual module freely can dismantle adjustment, and be easy to carrying, and module can carry out independent adjustment according to place concrete condition, can continuously, fully automatic operation.The utility model system can be used in the dystopy improvement of pollution of chromium place.Can thoroughly be detoxified by chromium-polluted soil, after process, soil there will not be " brightness reversion " phenomenon.
The utility model difference from prior art is that the utility model achieves following technique effect:
1, the utility model system can process the soil of the containing chromium slag contaminated site that alkalescence is comparatively strong, hexavalent chromium concentration is higher of left over by history, particularly high chromium concentration pollution;
2, the utility model system achieves chromic removing toxic substances and chromic stable by adding acidulant, reducing agent and stabilizing and curing agent, and after process, soil produces without " brightness reversion " phenomenon;
3, the utility model system equipment is comparatively perfect, for integrated module, comprise feeding module, Mechanical Crushing module, medicament preparation module, reaction module, Separation of Solid and Liquid module and recirculated water module, easy and simple to handle, stability is strong, be easy to strange land transport and install.
4, the utility model system achieves the recycling of technique waste water, non-secondary pollution.
Detailed description of the invention
Below in conjunction with drawings and Examples, to above-mentioned being described in more detail with other technical characteristic and advantage of the utility model.
As shown in Figure 1, the utility model provides a kind of modular to optimize integrated-type high chromium concentration contaminated soil remediation system adopting recirculating, this system comprises: the preparation of feeding module, Mechanical Crushing module, medicament module, reaction module, Separation of Solid and Liquid module, recirculated water module, medicament configuration module comprises sour dispensing system, reducing agent dispensing system and stabilizing and curing agent dispensing system.
Described feeding module comprises mechanical feeder 1, hanging vibratory sieve 2 and belt conveyor 3, described Mechanical Crushing module comprises overflow ball mill 4 and slurry storage tank 5, described sour dispensing system comprises sour storage tank 17, sour dispensing canister 18, first acid-proof pump 19 and acid solution metering device 20, described reducing agent dispensing system comprises reducing agent storage tank 22, reducing agent dispensing canister 23, second acid-proof pump 24 and reductant metering device 25, described stabilizing and curing agent dispensing system comprises powder frequency conversion batcher 27, conveying worm 28, stainless steel stirring and dissolving tank 29 and is furnished with the screw pump 30 of metering device, described reaction module comprises acidproof slush pump 6, anticorrosion retort 7, motor reducer 8 and anticorrosion paddle 9, described Separation of Solid and Liquid module comprises Pneumatic mud pump 10, plate and frame filter press 11 and blowpit 12, described recirculated water module comprises liquid storage tank 14 and water pump 15, hanging vibratory sieve 2 is installed in machinery feeder 1 bottom, hanging vibratory sieve 2 discharge end connects the afterbody of belt conveyor 3, the head of belt conveyor 3 is connected with the head inlet of overflow ball mill 4, the afterbody port of export of overflow ball mill 4 connects slurry storage tank 5, slurry storage tank 5 is connected with anticorrosion retort 7 by acidproof slush pump 6, in anticorrosion retort 7, top is motor reducer 8, motor reducer 8 connects the anticorrosion paddle 9 below it by power transmission shaft, acid storage tank 17 connects sour dispensing canister 18, acid dispensing canister 18 connects anticorrosion retort 7 by the first acid-proof pump 19 and acid solution flowermeter 20 through acid liquor delivery pipe net 21 successively, reducing agent storage tank 22 connects reducing agent dispensing canister 23, reducing agent dispensing canister 23 connects anticorrosion retort 7 by the second acid-proof pump 24 and reductant metering device 25 through reducing agent transmission pipeline network 26 successively, powder frequency conversion batcher 27 is successively by conveying worm 28, stirring and dissolving pump 29, the screw pump 30 being furnished with metering device connects anticorrosion retort 7, anticorrosion retort 7 is connected with plate and frame filter press 11 by Pneumatic mud pump 10, it is blowpit 12 below plate and frame filter press 11, top connects liquid storage tank 14 by outlet pipe 13, liquid storage tank 14 by water pump 15 and through hydraulic pipeline 16 respectively with sour dispensing canister 18, reducing agent dispensing canister 23, stainless steel stirring and dissolving tank 29 and overflow ball mill 4 are connected.
As shown in Figure 2, this is used for the system of chromium-polluted soil showering, is made up of following processing step:
1. by mechanical feeder material loading to hanging vibratory sieve, remove particle diameter and be greater than the bulky grain thing of 1cm, screenings delivers into overflow ball mill head inlet by belt conveyor, and during screening, soil moisture content must not more than 20%.This technique relies on feeding module to carry out practical operation;
2. the soil after screening is transported to overflow ball mill, its rotating speed controls at 15 ~ 20r/min, add the sulfuric acid solution wet-milling that concentration is 10-20%, need continue during wet-milling to add soil, when to overflow the solid-to-liquid ratio of slurries be 1:2.5 ~ 1:4, keep stable enter soil amount and inflow, the mud after levigate from the overflow of overflow ball mill afterbody to slurry storage tank.The hexavalent chromium concentration of solid phase, liquid phase in Simultaneously test slurry tank, according to mass conservation law determination sequential reduction agent 7H
2oFeSO
4consumption.This technique relies on Mechanical Crushing module and medicament preparation module to carry out practical operation;
3. the mud after acid being ground is squeezed in anticorrosion retort with acidproof slush pump, continuing to add water regulates solid-to-liquid ratio to be 1:5 ~ 1:6, the commercial sulphuric acid adding soil quality 12 ~ 15% regulates material pH in retort to be down to 4 ~ 6, ensure the abundant stripping of acid-soluble state Cr VI, and providing good sour environment for chromic reduction, acidization is 40 ~ 120min.This technique relies on reaction module to carry out practical operation;
4. the middle Cr VI that continues to add materials in anticorrosion retort fully reduces required medicament 7H
2oFeSO
4, addition is theoretical value 3 ~ 6 times, stirring reaction time 40 ~ 120min, ensures that in material, Cr VI is by medicament 7H
2oFeSO
4in reproducibility ferrous ion fully reduce.This technique relies on reaction module to carry out practical operation;
5. in material, add lime/flyash mixed stability curing agent, addition is 5 ~ 30% of quality of material, and pH value is neutralized to 8 ~ 9, stirring reaction time 40 ~ 120min.This technique relies on reaction module to carry out practical operation;
6. deliver to plate and frame filter press by Pneumatic mud pump and carry out Separation of Solid and Liquid, through be separated after water can be passed through circulation process up to standard after deliver to medicament preparation module and reaction module carry out reuse, final soil moisture content after reparation is less than 10%, and after repairing, soil directly need backfill after the maintenance of 5 ~ 30 days.This technique relies on Separation of Solid and Liquid module to carry out practical operation;
Wherein, in described step 1, need manual sorting to go out bulky grain stone etc., then by mechanical feeder material loading to hanging vibratory sieve, screenings deliver to overflow ball mill by belt conveyor.
Wherein, in described step 2, manually determine optimal wet time consuming when discharging particle diameter reaches 100 order, size abrading-ball injected volume.
Wherein, in described step 2, soil ratio during wet-milling is 1:2.5 ~ 1:4.
Wherein, in described step 3, the mud after overflow ball mill acid mill is squeezed into after in anticorrosion retort and is needed to add water adjustment solid-to-liquid ratio to 1:5 ~ 1:6.
Wherein, in described step 3, the commercial sulphuric acid adding soil quality 12 ~ 15% regulates material pH value 4 ~ 6 in retort, and acidization is 40 ~ 120min.
Wherein, in described step 4, in soil, Cr VI is all reduced the amount of required ferrous ion is theoretical value, 7H
2oFeSO
4actual addition be 3 ~ 6 times of theoretical value, stirring reaction time 40 ~ 120min.
Wherein, in described step 5, white lime adds water and is stirred to emulsus, ensure its can by soil can with reduction after trivalent chromium and ferric iron fully precipitate, add milk of lime and regulate material pH value 8 ~ 9, the reaction time is 40 ~ 120min.
Wherein, before step 1, measure initial chromic concentration in containing chromium slag contaminated soil, calculate for sequential reduction course of reaction reduction added amount of chemical.Meanwhile, processing procedure needs Real-Time Monitoring material Cr VI removing toxic substances situation, ensures treatment effect.
The utility model tool has the following advantages:
1. the utility model system can process exchangeable species, carbonate in conjunction with state, iron and manganese oxides in conjunction with the containing chromium slag contaminated soil in the higher left over by history pollution of chromium place of the form content of 6-valence Cr ions such as state, and its hexavalent chromium concentration is mostly at 4000 ~ 8000mg/kg.
2. the containing chromium slag contaminated soil Treatment process of the utility model system proposition, for left over by history pollution of chromium place chromium-polluted soil dystopy reduction-stabilisation/curing technology, it uses commercial sulphuric acid as acidulant, ferrous sulfate heptahydrate and lime/mixture of fly ash are as reducing agent, stabilizing and curing agent, make the Cr VI in soil generate stable Cr (OH) 3 to precipitate, Environmental capacity index limits when total chromium content in soil after removing toxic substances and chromic leaching concentration are used as roadbed material and aggregate lower than chromium slag in " chromium slag contaminated Environment control resist technology specification " (provisional) (HJ/T 301-2007), i.e. Cr6+≤0.5mg/L, total chromium≤1.5mg/L, reduction is stablized rate and is reached more than 99%, after process, soil has long-time stability.
3. the utility model system can make the containing chromium slag contaminated soil in left over by history pollution of chromium place be repaired, the dystopy that can be applied to place is administered, its efficient, economic, practical property is strong, simple to operate, compare the recovery techniques such as chemical leaching and greatly reduce water resources consumption, be particularly useful for exchange state, carbonate in conjunction with state, iron and manganese oxides in conjunction with form content of 6-valence Cr ions higher chromium contaminated soils such as states." brightness reversion " phenomenon of soil after this technology effective solves and repairs.
Above-described embodiment is only be described preferred embodiment of the present utility model; not scope of the present utility model is limited; under the prerequisite not departing from the utility model design spirit; the various distortion that those of ordinary skill in the art make the technical solution of the utility model and improvement, all should fall in protection domain that the utility model claims determine.
Embodiment 1: adopting EPA3060a alkali resolution method to measure chromic concentration in chromium-polluted soil is 7270mg/kg, machinery feeder material loading is to hanging vibratory sieve, sulfuric acid acidation is added to pH value 4 ~ 6 after overflow ball mill wet-milling, add the green vitriol of 3 ~ 6 times carrying out the theoretical value of chemical reaction with Cr VI in soil again, abundant stirring 40 ~ 120min, adds emulsus Ca (OH) in material
2, reaction 40 ~ 120min, is neutralized to 8 ~ 9 by pH value, delivers to plate and frame filter press carry out Separation of Solid and Liquid by Pneumatic mud pump.
Test result; after repairing, in soil extract, hexavalent chromium concentration is 0.31mg/L; total chromium concn is 1.03mg/L; lower than chromium slag in " chromium slag contaminated Environment control resist technology specification " (provisional) (HJ/T 301-2007) as Environmental capacity index limits when roadbed material and aggregate; namely total chromium≤1.5mg/L, Cr6+≤0.5mg/L in the leachate prepared according to " solid waste Leaching leaching method-sulfonitric method " (HJ/T 299-2007).
Embodiment 2:
Adopting EPA3060a alkali resolution method to measure chromic concentration in chromium-polluted soil is 4820mg/kg, machinery feeder material loading is to hanging vibratory sieve, sulfuric acid acidation is added to pH value 4 ~ 6 after overflow ball mill wet-milling, add the green vitriol of 3 ~ 6 times carrying out the theoretical value of chemical reaction with Cr VI in soil again, abundant stirring 40 ~ 120min, adds emulsus Ca (OH) in material
2, reaction 40 ~ 120min, is neutralized to 8 ~ 9 by pH value, delivers to plate and frame filter press carry out Separation of Solid and Liquid by Pneumatic mud pump.
Test result; in rehabilitating soil leachate, hexavalent chromium concentration is 0.47mg/L; total chromium concn is 1.37mg/L; lower than chromium slag in " chromium slag contaminated Environment control resist technology specification " (provisional) (HJ/T 301-2007) as Environmental capacity index limits when roadbed material and aggregate; namely total chromium≤1.5mg/L, Cr6+≤0.5mg/L in the leachate prepared according to " solid waste Leaching leaching method-sulfonitric method " (HJ/T 299-2007).
Above-described embodiment is only be described preferred embodiment of the present utility model; not scope of the present utility model is limited; under the prerequisite not departing from the utility model design spirit; the various distortion that those of ordinary skill in the art make the technical solution of the utility model and improvement, all should fall in protection domain that the utility model claims determine.