WO2019037562A1 - 土壤、固体废物中污染物的化学淋洗分离方法及其分离系统 - Google Patents

土壤、固体废物中污染物的化学淋洗分离方法及其分离系统 Download PDF

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WO2019037562A1
WO2019037562A1 PCT/CN2018/096200 CN2018096200W WO2019037562A1 WO 2019037562 A1 WO2019037562 A1 WO 2019037562A1 CN 2018096200 W CN2018096200 W CN 2018096200W WO 2019037562 A1 WO2019037562 A1 WO 2019037562A1
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rinsing
liquid
concentration
soil
eluent
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PCT/CN2018/096200
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English (en)
French (fr)
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张晨
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张晨
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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
    • B09C1/02—Extraction using liquids, e.g. washing, leaching, flotation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/26—Treatment of water, waste water, or sewage by extraction
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds

Definitions

  • the invention relates to the technical field of soil and solid waste pollution control, in particular to a chemical leaching separation method and a separation system for high concentration and full circulation soil pollutants.
  • the method mainly comprises contacting the eluent containing the eluent with the soil or solid waste to be treated, so that the contaminant in the material interacts with the eluent in the eluent, and desorbs, sequesters and complexes. Physical and chemical processes such as dissolution or extraction to transfer contaminants to the eluent to purify soil or solid waste.
  • the existing chemical leaching method generally has problems such as serious secondary pollution load and high operating cost when conducting soil and solid waste pollution control, which leads to its large-scale promotion and application in the engineering field.
  • a soil with a dry weight of 10t has a lead content of 1000mg/kg, and the target of repair is to reduce the lead content in the soil to less than 150mg/kg; the actual moisture content of the soil is 21% (dry basis water)
  • the saturated water content of the soil is 52%, and the water content of the saturated aqueous soil can be reduced to 30% after economically feasible dewatering measures.
  • the existing chemical leaching method is adopted for the treatment of pollution, specifically: chemical leaching is carried out using an EDTA-disodium solution having a concentration of 0.01 to 0.1 mol/L, and after a chelation reaction of about 1 h, The lead originally present in the solid phase in the soil is eluted with an efficiency of up to 90% and enters the liquid phase in the form of a solute of the lead chelate.
  • the liquid-solid ratio parameter (the ratio of eluent quality to soil quality) has a decisive influence on the final treatment effect and wastewater yield.
  • the existing chemical leaching process is usually selected.
  • the liquid-solid ratio is 2-10 (liquid to solid mass ratio). Therefore, we analyze the production of wastewater in the existing chemical leaching process by taking the liquid-solid ratio of 2.0, 2.85 and 5.4 as examples. :
  • the EDTA-disodium solution with a volume of 20 m 3 and a concentration of 0.01-0.1 mol/L was added to the soil for chemical leaching. After 1 h of chelation reaction, the lead in the soil was eluted with an efficiency of 90%. The total amount of lead entering the eluent is 9kg and the concentration is 450mg/L.
  • the soil after chemical leaching is subjected to solid-liquid separation. After separation, the soil moisture content is 30%, the water content is 3m 3 , and the lead content is 7.65.
  • Kg concentration 450mg/L eluate 17m 3 ; after solid-liquid separation, the residual solid phase and uneluted lead in the soil is 1kg, and the mass of chelated lead in the 3m 3 eluent in the soil is 1.35.
  • Kg the total lead mass in the solid phase and liquid phase is 2.35kg, and the total lead content is 235mg/kg based on the dry weight of soil, which does not reach the repair target of 150mg/kg, so it must be at least after chemical leaching. Reintroduced in the soil The water is rinsed, rinsed and then solid-liquid separated to a soil moisture content of 30%.
  • the lead quality in the soil liquid phase is reduced to 0.5 kg, and the total lead quality in the solid phase and liquid phase is reduced to 1.5 kg, reaching 150 mg. /kg repair target, while 0.85kg of chelated lead enters the eluate of the rinsing process, forming a leaching solution of lead concentration of 166.67mg / L 5.1m 3 .
  • lead concentration 166.67mg / L eluate 5.1m 3 the total amount of wash liquid waste 22.1m 3.
  • the EDTA-disodium solution with a volume of 40 m 3 and a concentration of 0.01-0.1 mol/L was added to the soil for chemical leaching. After 1 h of chelation reaction, the lead in the soil was eluted with an efficiency of 90%. The total amount of lead entering the eluent is 9kg and the concentration is 225mg/L.
  • the soil after chemical leaching is subjected to solid-liquid separation. After separation, the soil moisture content is 30%, the water content is 3m 3 , and the lead content is 8.325.
  • Kg concentration 225mg/L eluate 37m 3 ; after solid-liquid separation, the residual solid phase and uneluted lead in the soil is 1kg, and the mass of chelated lead in the 3m 3 eluent in the soil is 0.675.
  • Kg the total lead mass in the solid phase and liquid phase is 1.675kg, and the total lead content is 167.5mg/kg based on the dry weight of soil, which does not reach the repair target of 150mg/kg, so it must be at least chemically rinsed. After the soil was re-introduced with 1.05m 3 of water, it was rinsed. After rinsing, the solid-liquid separation was carried out until the soil moisture content was 30%.
  • the lead quality in the soil liquid phase was reduced to 0.5 kg, and the total in the solid phase and the liquid phase.
  • the lead quality was reduced to 1.5kg, reaching the repair target of 150mg/kg, while 0.175kg of chelated lead was introduced into the rinse.
  • the eluate formed 166.67mg / L wash the lead concentration was 1.05m 3.
  • lead concentration 166.67mg / L eluate 1.05m 3
  • the EDTA-disodium solution with a volume of 54 m 3 and a concentration of 0.01 to 0.1 mol/L was added to the soil for chemical leaching. After 1 h of chelation reaction, the lead in the soil was eluted with an efficiency of 90%. The total amount of lead entering the eluent was 9kg and the concentration was 166.667mg/L.
  • the soil after chemical leaching was subjected to solid-liquid separation. After separation, the soil moisture content was 30%, the water content was 3m 3 , and the lead content was formed during the separation process.
  • the present invention provides a chemical leaching separation method and a separation system for pollutants in high-concentration, full-circulation soil and solid waste to solve the problem of chemical leaching of soil and solid waste during the previous chemical leaching treatment.
  • the ubiquitous secondary pollution load is serious and the operating costs are too high.
  • One aspect of the invention provides a chemical leaching separation method for contaminants in high concentration, full circulation soil and solid waste, the separation method comprising the following steps:
  • Chemical leaching the soil and solid waste to be treated are placed in the eluent for chemical leaching, and then solid and liquid are separated to obtain soil and solid waste after leaching, wherein the eluent has a constant volume
  • the eluent contains a leaching agent and a contaminant, and the concentration of the contaminant in the eluent is constant, and the constant concentration value of the contaminant is N times the inclusion of the solution in the soil or solid waste.
  • Countercurrent rinsing the above-mentioned leached soil and solid waste are subjected to countercurrent rinsing until the concentration of the pollutant in the soil and solid waste is equal to the concentration of the treatment target, and the soil and solid waste after the reverse rinsing are discharged, and at the same time
  • Regeneration cycle when the concentration of the pollutant in the eluent is greater than the set constant concentration, the eluent is partially output for contaminant extraction, and the eluent after extracting the contaminant is returned to the chemical leaching step In the eluent or after the countercurrent rinsing eluate is subjected to pollutant extraction, the eluate after extracting the contaminant is returned to the eluent of the chemical leaching step until the eluent
  • the concentration of the pollutant is equal to the set constant concentration; when the volume of the eluent is greater than the set constant volume, the eluent portion is outputted for reverse osmosis to obtain a permeate and a concentrated solution or to rinse the countercurrent
  • the subsequent eluate is subjected to reverse osmosis to obtain a permeate and a concentrated solution, and the concentrated solution is returned to the eluent of the chemical elution step until the elu
  • the contaminant is an organic substance
  • the eluent is an organic solution capable of dissolving the organic substance or the contaminant is a heavy metal compound which is poorly soluble in water, and the eluent is a chelating agent, an acid or a base;
  • the contaminant is a heavy metal compound that is readily soluble in water and the eluent is water.
  • a plurality of rinsing tanks are sequentially disposed, and the leached soil and solid waste are delivered to the first rinsing tank in batches, and rinsed by the rinsing liquid in the first rinsing tank.
  • the rinsed soil and solid waste are transferred to a second rinsing tank, rinsed by the rinsing liquid in the second rinsing tank, and so on, until the soil and solid waste pass through the rinsing liquid in the last rinsing tank.
  • the rinsing liquid in the first rinsing tank is discharged as a washing liquid when the concentration of the pollutant in the rinsing liquid reaches the concentration of the pollutant treatment target in the last rinsing tank, and the second rinsing tank is discharged.
  • the rinsing liquid is moved to the first rinsing tank as a rinsing liquid, and so on, until the rinsing liquid in the last rinsing tank is moved to the upper rinsing tank as a rinsing liquid, and then added in the last rinsing tank. Fresh rinse solution.
  • the countercurrent rinsing step is provided with a plurality of countercurrent rinsing branches, and each countercurrent rinsing branch is provided with a countercurrent rinsing unit;
  • the soil and the solid waste are sequentially input into different countercurrent rinsing branches, and the rinsing of the mixed solution in the soil and the solid waste is performed through the countercurrent rinsing unit of each of the countercurrent rinsing branches.
  • the concentration of the substance is equal to the concentration of the treatment target, and the volume of the rinse liquid in each of the countercurrent rinsing units is the same;
  • the washing liquid after the first rinsing in the rinsing unit of each countercurrent rinsing branch is input into the leaching liquid of the chemical rinsing step, and the Wth rinsing in the rinsing unit of the Mth countercurrent rinsing branch
  • the eluate is input to the rinsing unit of the M+1th countercurrent rinsing branch rinsing unit as the W-1 rinsing rinsing liquid of the rinsing unit
  • the M is a natural number greater than or equal to 1
  • the W is greater than or equal to 2 Natural number.
  • each of the periodic rinses comprises, in order, agitation rinsing and solid-liquid separation.
  • the permeate is supplied to the countercurrent rinsing step as a rinsing liquid.
  • Another aspect of the invention also provides a chemical leaching separation system for high concentration, full circulation soil contaminants, the system being suitable for the above chemical leaching separation method, the system comprising: conveying device 2, solid liquid Separating device 3, countercurrent rinsing device 4, reverse osmosis device 5, pollutant extraction device 6 and chemical rinsing device 1 for containing eluent;
  • the chemical rinsing device 1 is respectively provided with a concentration detector 11 for detecting the concentration of pollutants in the eluent and a volume detector 12 for detecting the volume of the eluent, the chemical rinsing device 1 Solid output is connected to the input end of the conveying device 2;
  • An output end of the conveying device 2 is connected to an input end of the solid-liquid separating device 3;
  • the solid output end of the solid-liquid separation device 3 is connected to the solid input end of the countercurrent rinsing device 4 through a pipeline 7, and the pipeline 7 is provided with a valve 71, and the liquid output of the solid-liquid separation device 3 The end is connected to the liquid input end of the chemical elution device 1;
  • the liquid input end of the countercurrent rinsing device 4 is respectively connected to a fresh water source and a permeate output end of the reverse osmosis device 5, the liquid output end of the countercurrent rinsing device 4 and the liquid input end of the chemical leaching device 1 connection;
  • An input end of the reverse osmosis device 5 is connected to a liquid output end of the chemical leaching device 1, and a concentrated solution output end of the reverse osmosis device 5 is connected to a liquid input end of the chemical leaching device 1;
  • An input end of the pollutant extraction device 6 is connected to a liquid output end of the chemical elution device 1, and a liquid output end of the pollutant extraction device 6 is connected to a liquid input end of the chemical elution device 1;
  • the output end of the concentration detector 11 is connected to the control end of the pollutant extraction device 6, and the output end of the volume detector 12 is connected to the control end of the reverse osmosis device 5.
  • the countercurrent rinsing device 4 is composed of a plurality of countercurrent rinsing branches 41 arranged in parallel, and each of the countercurrent rinsing branches 41 is provided with a rinsing device 411 and an eluate temporary storage tank 412;
  • the solid input end of the rinsing device 411 is connected to the solid output end of the solid-liquid separating device 3 through the pipeline 7, and the pipeline 7 is provided with a valve 71, and the liquid input ends of the rinsing device 411 are respectively a fresh water source and a permeate output end of the reverse osmosis device 5 are connected, and a liquid output end of the rinsing device 411 is connected to an input end of the eluate temporary storage tank 412;
  • the output end of the eluate temporary storage tank 412 is respectively connected to the liquid input end of the chemical elution device 1 and the liquid input end of the rinsing device 411 in the next countercurrent rinsing branch 41;
  • the rinsing device 411 is a pressure filter device
  • the rinsing device 411 includes a housing 4111, a rotating chamber 4112, a first motor 4113, a stirring rod 4114, and a second motor 4115;
  • the rotating bin 4112 is spaced apart from the through hole, and the rotating bin 4112 is rotatably mounted inside the casing 4111;
  • the output end of the first motor 4113 is drivingly connected to the upper end of the stirring rod 4114, and the lower end of the stirring rod 4114 is inserted inside the rotating chamber 4112;
  • the driving end of the second motor 4115 is drivingly coupled to the rotating bin 4112.
  • the output end of the eluate storage tank 412 is also connected to the input end of the reverse osmosis device 5 and the input end of the contaminant extraction device 6, respectively.
  • the concentrated solution output of the reverse osmosis device 5 is also connected to the input of the contaminant extraction device 6.
  • the contaminant extraction device 6 is an electrodialysis device or an extraction device.
  • the chemical leaching separation method for high-concentration, full-circulation soil and solid waste in the present invention is mainly divided into a chemical leaching step, a counter-current rinsing step and a regeneration cycle step, wherein first, in the chemical leaching step The high-concentration eluent reacts with the pollutants in the soil and solid waste, so that the pollutants in the soil and solid waste are dissolved as solute in the eluent, and then the soil and solid waste are washed by the countercurrent rinsing step. The pollutants in the inclusion solution as solute are partially replaced by the rinsing liquid until the pollutant concentration of the inclusion solution in the soil and solid waste is equal to the target concentration of the treatment, and the discharge is achieved to meet the treatment requirements.
  • the regeneration cycle step is dynamically started during the chemical rinsing step and the countercurrent rinsing step, and the start of the regeneration cycle step enables the soil and solid waste to maintain the volume of the leaching solution and the leaching solution during the entire pollutant treatment process.
  • the concentration of contaminants in the wash solution is constant to achieve a stable cycle.
  • the chemical elution separation method provided by the invention can convert the pollutants in the soil and the solid waste into the solute and dissolve in the eluent by the setting of the high-concentration eluent, so as to facilitate the subsequent countercurrent rinsing step;
  • the total mass of pollutants removed per unit time is a constant value, and therefore, the solution for extracting pollutants through the regeneration cycle step.
  • the product of pollutant concentration, solution flow rate, and pollutant removal rate is a constant value. If the difference in removal efficiency is not considered, the solution concentration is inversely proportional to the solution flow rate.
  • the invention requires a chemical eluent and a reverse osmosis concentrated solution which are transported to the pollutant extraction site, and the pollutant concentration thereof is at least N times of the pollutant concentration of the inclusion solution in the soil and solid waste after the treatment, and N ⁇ 2, the principle is to greatly increase the concentration of pollutants in the solution delivered to the pollutant extraction to a certain high concentration value, so that the amount of solution to be treated for pollutant extraction is correspondingly reduced.
  • increasing the concentration of the contaminant in the solution generally has a positive effect on improving the efficiency of the treatment of the contaminant extraction, and correspondingly, the amount of the solution to be treated for contaminant extraction is further reduced.
  • the present invention makes the amount of the solution requiring the pollutant extraction treatment drastically reduced, it is possible to avoid a large amount of efflux of the low-concentration wastewater, and accordingly, the amount of loss of the chemical eluent is greatly reduced.
  • the chemical leaching separation system for the high concentration and full circulation soil contaminants provided by the invention is suitable for the above chemical leaching separation method, and has the advantages of simple structure, reasonable design and convenient use.
  • FIG. 1 is a schematic flow chart of a chemical leaching separation method for pollutants in a high-concentration, full-circulation soil and solid waste according to an embodiment of the present disclosure
  • FIG. 2 is a schematic structural view of a chemical leaching separation system for high-concentration, full-circulation soil contaminants according to an embodiment of the present invention, wherein 8 represents slag, soil material bucket, and 9 represents a supplementary leaching agent;
  • FIG. 3 is a schematic structural view of a chemical leaching separation system for high-concentration, full-circulation soil contaminants according to an embodiment of the present invention, wherein 8 represents slag, soil material hopper, and 9 represents a supplementary leaching agent.
  • the chemical leaching separation method for the high-concentration, full-circulation soil and solid wastes provided by the embodiment is intended to solve the above-mentioned related problems simultaneously by substantially reducing the amount of process wastewater generated, and to regenerate the soil or solid The economic costs of waste disposal have been significantly reduced.
  • Chemical leaching the soil and solid waste to be treated are placed in the eluent for chemical leaching, and then solid and liquid are separated to obtain soil and solid waste after leaching.
  • the volume of the eluent is constant.
  • the washing liquid contains eluent and contaminant, and the concentration of the contaminant in the eluent is constant, and the constant concentration of the contaminant is N times the target concentration of the contaminant in the soil and the solid waste;
  • Countercurrent rinsing the above-mentioned leaching soil and solid waste are subjected to countercurrent rinsing until the pollutant concentration of the inclusion solution in the soil and solid waste is equal to the target concentration of the treatment, and the soil and solid waste after the reverse rinsing are discharged, and the countercurrent rinsing is performed.
  • N the concentration of pollutants in the inclusions in the waste
  • N ⁇ 2 it should be noted that the rinsing efficiency N of any one of the set rinsing systems is a fixed parameter value during stable operation;
  • Regeneration cycle When the concentration of pollutants in the eluent is greater than the set constant concentration, the eluent is partially output for contaminant extraction, and the eluent after the contaminant is returned to the eluent of the chemical leaching step. After the pollutants are extracted from the washing liquid after the countercurrent rinsing, the eluate after the contaminant is extracted is returned to the eluent of the chemical leaching step until the concentration of the contaminant in the eluent is equal to the set constant.
  • Concentration when the volume of the eluent is larger than the set constant volume, the eluent is partially output for reverse osmosis, and the permeate and the concentrated solution are obtained or the eluate after the countercurrent rinsing is subjected to reverse osmosis to obtain a permeate and a concentrated solution.
  • the solution is returned to the eluent of the chemical rinsing step until the eluent volume is equal to the set constant volume, wherein the concentration of the contaminant in the concentrated solution is greater than or equal to the constant concentration set in the chemical rinsing step value.
  • the constant concentration value set in the regeneration cycle step is the same as the constant concentration concentration of the pollutant in the eluent in the chemical rinsing step; the constant volume value set in the regeneration cycle step and the chemical leaching step The eluent has the same constant volume.
  • a sorting step may be added before the chemical leaching step to remove stones, gravel or other materials that need not be treated. To reduce the operational load of the various process steps at the back end.
  • the eluent when the pollutant is an organic substance, the eluent is an organic solution capable of dissolving the organic substance; when the contaminant is a heavy metal compound which is insoluble in water, the eluent is a chelating agent, an acid or a base; when the contaminant is easily soluble In the case of heavy metal compounds in water, the eluent is water.
  • poorly soluble in water means that the amount dissolved in 100 g of water is less than 0.1 g at 20 ° C
  • soluble in water means that the amount dissolved in 100 g of water is greater than 10 g at 20 ° C.
  • the eluent when the pollutant is organic matter such as DDT or hexachlorocyclohexane, the eluent may be an organic solvent capable of dissolving the above organic substance such as n-hexane; when the pollutant is a heavy metal compound which is hardly soluble in water such as chromium oxide or lead oxide.
  • a chelating agent such as EDTA disodium or oxalic acid or an acid or a base such as sulfuric acid or sodium hydroxide may be used; when the contaminant is a heavy metal compound which is easily soluble in water such as copper sulfate, the eluent may be selected from water.
  • 1 is a process flow diagram of a chemical leaching separation method provided by the present invention, wherein: 1 chemical rinsing step (corresponding to a high concentration chemical leaching system), and a high concentration chemical leaching system receiving externally sent processing needs to be processed Soil, solid waste and other materials (stream S), the eluent in the high-concentration chemical leaching system contains eluents and contaminants, and the so-called high concentration mainly refers to the higher concentration of pollutants, which is N
  • the target concentration of the pollutants in the mixed solution of soil and solid waste which is derived from the fresh eluent stream C and the repellent eluent from other steps, so that the soil and solids to be treated are required.
  • the waste and other materials interact with the eluent, and the pollutants in the soil, solid waste and other materials to be treated are dissolved as solute and eluent, and then the chemically leached material is solid-liquid separated.
  • the material after removing part of the liquid is removed in the form of stream A and sent to the countercurrent rinsing system; 2 the countercurrent rinsing step (corresponding to the countercurrent rinsing system), and the countercurrent rinsing system receives the high concentration
  • the stream A output from the rinsing system and the rinsing liquid stream U input from the outside interact with each other, and then the rinsed material is solid-liquid separated, and the material after removing the liquid is discharged.
  • the flow G (as a process product) is removed, and the eluate produced by the rinsing is removed to form an eluate stream H, which is partially or completely sent as a stream E directly to the high concentration chemical leaching system.
  • the eluent is reused, the remainder is the liquid stream J, and sent to the regeneration cycle system; 3 the regeneration cycle step (corresponding to the regeneration cycle system), the startup of the regeneration cycle system is mainly based on the high concentration chemical elution system
  • the volume of the liquid and the concentration of contaminants in the eluent are determined by the high concentration chemical leaching system when the concentration of contaminants in the eluent exceeds the set constant concentration or the eluent volume exceeds the set constant volume.
  • the eluent stream B or the countercurrent rinsing system outputs the eluate stream J, and the contaminant-containing stream is chemically or physically treated by the regeneration cycle system to reduce or reduce the concentration of the contaminant.
  • the product forms a regenerating eluent, a regenerating rinsing liquid, and a contaminant separated from the solution.
  • the regenerating eluent is transported as a liquid stream D to the high-concentration chemical leaching system for reuse as a leaching solution, and the regenerating rinsing liquid is regenerated.
  • the form of stream R is removed from the regeneration cycle system and sent in whole or in part to the countercurrent rinsing system for reuse as a rinsing liquid. Contaminants separated from the solution are removed to the outside of the system to form a contaminant stream P.
  • high-concentration chemical leaching system in a certain stable production time period T, the stream S entering the high-concentration chemical leaching system has a mass X S pollutant X After chemical leaching and eluent reaction, it is dissolved as solute in the eluent. For the solid phase and liquid phase mixture formed during the rinsing process, it is required to control the mass concentration C X of the pollutant X in the liquid phase of the system.
  • N N * C 0
  • N N * C 0
  • C A The concentration of contaminant X in the solution carried by stream A
  • C G the contaminant X degree of the solution carried by stream G
  • C 0 the pollutant treatment of the inclusion solution in the set soil and solid waste.
  • target concentration it should be noted that the rinsing efficiency N of any one of the set rinsing systems is a fixed parameter value during stable operation.
  • the volume of the solution entering and discharging the high-concentration chemical leaching system per unit time is controlled by the process flow, so that the total solution volume in the system is stabilized at a certain fixed value V T .
  • the volume of solution entering the system includes: the amount of solution volume V S in the stream S, the volume of the regenerated eluent stream D delivered by the regeneration cycle system, V D , and the washing out from the countercurrent rinsing system.
  • the volume of the liquid stream E is V E ; the volume of the solution removed from the system includes: the volume of the eluate stream B output from the chemical leaching system V B , and the solution in the stream A output from the chemical leaching system
  • the amount of pollutant X entering and discharging the liquid phase of the high-concentration chemical leaching system per unit time is controlled by the process flow, that is, can.
  • the amount of entry per unit time is greater than the amount of outflow, the pollutant X is continuously enriched in the eluent and the C X value is increased; when the amount per unit time is less than the outflow, the total amount of contaminant X in the eluent Continuously decreasing, the C X value is decreased; when the amount of entry per unit time is equal to the outflow amount, the concentration C X of the pollutant X in the solution remains stable.
  • Contaminant X mass M IN entering the solution in the system includes: the amount of contaminant X in the stream S is eluted M S , the contaminant X mass M D of the regenerating eluent stream D delivered by the regenerative circulation system
  • the pollutant X mass M E of the eluate stream E delivered by the countercurrent rinsing system, ie, M IN M S +M D +M E
  • the pollutant X entering and discharging the high concentration chemical leaching system solution per unit time is controlled by the process flow.
  • the C X value fluctuates and exceeds N*C 0 , by increasing the volume flow of the liquid flow B or the liquid flow J or increasing the removal rate ⁇ of the regeneration cycle system, the pollution is more per unit time.
  • the substance X is removed by the regeneration circulatory system, correspondingly reducing the C X value in the M IN ⁇ M OUT , high concentration chemical leaching system to N*C 0 ; the C X value is decreasing and appearing or may appear below N*C In the case of 0 , the flow rate of the liquid flow B, the liquid flow J is reduced or the removal rate ⁇ of the regeneration cycle system is reduced, so that less pollutant X per unit time is removed by the regeneration cycle system, correspondingly The C X value in M IN >M OUT , high concentration chemical elution system is increased to N*C 0 .
  • M G is the final product of the process flow, that is, the output of the rinsing system
  • the concentration of pollutant X in the solution carried by the flow G) so by setting the concentration C X of the high concentration chemical leaching system in the stable operation stage to a higher concentration of N*C 0 to reduce the need for the regeneration cycle system to be treated The volume flow of the eluate.
  • V B *C 0 * ⁇ B +V J *C J * ⁇ J M S , (wherein ⁇ B and ⁇ J are the removal of pollutant X in liquid flow B and liquid flow J by the regeneration cycle system, respectively) Rate, C J is the concentration of the pollutant X in the liquid stream J).
  • a multi-stage intermittent countercurrent rinsing may be selected, in particular, a plurality of rinsing tanks are sequentially disposed in the countercurrent rinsing step, and the soil and the solid waste are delivered to the first rinsing tank in batches after rinsing, by the first After the rinsing liquid in a rinsing tank is rinsed, the rinsed soil and solid waste are transferred to the second rinsing tank, rinsed by the rinsing liquid in the second rinsing tank, and so on, until the soil and the solid are solid. The waste is removed after being rinsed by the rinse liquid in the last rinse tank.
  • the rinse liquid in the first rinse tank is used as the eluate Discharge, and move the rinse liquid in the second rinse tank to the first rinse tank as a rinse liquid, and so on, until the rinse liquid in the last rinse tank is moved to the previous rinse tank as a rinse liquid. Thereafter, fresh rinsing liquid is replenished in the last rinsing tank, wherein the amount of soil and solid waste conveyed in each batch is equal.
  • the content of the contaminant in the inclusion solution in the soil and solid waste after the rinsing step using the above-described countercurrent rinsing step is always fluctuating from low to high, resulting in a problem that the rinsing effect is unstable.
  • a countercurrent rinsing system (countercurrent rinsing step): a preferred countercurrent rinsing method in the chemical leaching method provided by the present embodiment, which requires the eluent stream H produced by the countercurrent rinsing system to have a pollutant X concentration C.
  • the rinsing liquid stream U accepted by the system includes the fresh rinsing liquid flow F input from the outside of the process flow, R regeneration regeneration rinse liquid flow circulation system output, stable production in a certain period of time T, if the high concentration of the chemical leaching solution volume V lOSS losses in the system and the recycling system or chemical reaction caused by physical evaporation material is greater than
  • the amount of solution volume in the flow S is V S , and the eluate produced by the countercurrent rinsing system is compensated to a solution of V COMP in a high-concentration chemical leaching system and a regenerative circulation system [V COMP ⁇ (V LOSS -V S )], the fresh rinsing liquid flow F input from the outside of the process flow should be controlled.
  • the liquid volume amount V F is equal to the sum of the liquid volume amounts V G and V COMP carried by the stream G output by the system. That V F V G + V COMP; in other cases except the aforementioned case, the control should be V F ⁇ V G; and the object of the above process parameters are selected: ensuring high concentration of the chemical leaching system, the total volume of solution in the regeneration cycle will not be Due to the excessive volume of V F input externally to the process flow, there is a growing instability.
  • the countercurrent rinsing step is preferably provided with a plurality of countercurrent rinsing branches, and each countercurrent rinsing branch is provided with a countercurrent rinsing unit, and the soil and solid waste after rinsing are sequentially input into different countercurrent rinsing branches in batches.
  • the liquid is input into the rinsing unit of the M+1 countercurrent rinsing branch as the rinsing liquid of the W-1 rinsing of the rinsing unit, and M is a natural number greater than or equal to 1, and W is a natural number greater than or equal to 2, wherein the countercurrent
  • the number of rinsing branches is equal to the number of rinsings required for each rinsing unit to rinse a batch of soil and solid waste to the desired level of treatment.
  • the material A to be rinsed enters the countercurrent rinsing system in batches, and the countercurrent rinsing system includes Q countercurrent rinsing branches (Q is a natural number greater than or equal to 2), and each batch of materials
  • Q is a natural number greater than or equal to 2
  • each batch of materials The quality of A is equal, and after rinsing, it is removed from the system and becomes a product of the process.
  • Each batch of materials is named A 1 , A 2 , A 3 ... A X ... (X is a positive integer) in the order in which they are processed through the process flow, and each batch of materials is sequentially input to each rinse.
  • Q times (Q is the set of any natural number greater than or equal to 2) rinsing process, called Q-stage countercurrent rinsing system, in the rinsing system, in which the countercurrent rinsing system is used
  • the number of rinsing branches is equal to the number of rinsing times of a batch of materials in each rinsing section of the countercurrent rinsing branch, and any grading of the material A X (a is a positive integer, 1 ⁇ a ⁇ Q) is:
  • the rinsing liquid used in the process is mixed with the rinsing material to form a mixture.
  • the pollutant X in the rinsing material is uniformly dispersed into the mixture in the form of dissolved matter by dissolution, diffusion, dilution or chemical reaction.
  • the eluate containing the contaminating substance X is separated from the mixture, and the remainder after separating the eluate is the washed material of the material A X in the a-stage rinsing process.
  • the backing is the final product of the countercurrent rinsing system and the whole process, and is removed from the system;
  • the rinsing liquid used in the rinsing process of the material A X in the ath (a is a positive integer and 1 ⁇ a ⁇ Q) is the material A X-1
  • the rinsing liquid used for the material A X in the Qth rinsing process is the rinsing liquid stream F input from the outside of the countercurrent rinsing system;
  • the material A X is at the first the eluate views generated during rinsing, the system formed is removed eluate stream H;
  • N Q C A /C G
  • N 2 (K+1) 2 -K
  • N 3 (K+1)*N 2 -K*(K+1)
  • Q >3, N Q (K+1)*N Q-1 -K*N Q-2 .
  • C A is the concentration of contaminant X in the solution carried by material stream A
  • C G is the concentration of contaminant X in the solution of the countercurrent rinsing system output stream G
  • Q is the number of rinsing times set by the system
  • M A is the mass of contaminant X in the solution of material stream A
  • M G is the mass of contaminant X in the solution of the countercurrent rinsing system output stream G
  • M H The mass of the pollutant X in the eluate stream H output for the countercurrent rinsing system
  • V U In order to input the volume of the rinsing liquid flow U of the countercurrent rinsing system; V H is the volume of the eluate flow H output by the countercurrent rinsing system);
  • the treated eluate generated in each countercurrent rinsing step is only the eluate produced by the first rinsing of each batch of the rinsing material, and the second and even the Qth rinsing
  • the subsequent eluate can be reused multiple times, which can greatly reduce the amount of eluate produced, reduce the amount of sewage to be treated, and reduce the composition of sewage treatment.
  • the batches are rinsed first.
  • the eluate produced by the secondary rinsing is discharged after repeated use, so the concentration of the pollutants in the ejected liquid discharged is high, and if processed by the reverse osmosis device, a thicker concentration containing the higher concentration of pollutants is obtained.
  • the solution is sent to the pollutant extraction device for treatment. Due to the high concentration of the pollutant, the volume of the solution to be treated can be greatly reduced, and the difficulty of treatment and the treatment cost can be reduced, and the existing technology can be better solved. problem.
  • each rinsing unit performs a solid-liquid separation step after performing the usual stirring rinsing step, which can significantly improve the rinsing efficiency of the rinsing unit.
  • the number of rinsing needs to be reduced, and the cost is reduced.
  • the permeate is input to the countercurrent rinsing step as a rinsing liquid.
  • the preferred rinsing mode is divided into a plurality of rinsing branches, one rinsing unit is set in each branch, and any rinsing unit can independently complete the rinsing of a batch of materials, and the concentration of the pollutants after rinsing reaches the target value of the treatment.
  • multi-stage intermittent countercurrent rinsing is divided into multiple units, but any batch of materials must pass through several units in series to make the concentration of pollutants after rinsing reach the target value, that is, only one unit is externally output. The soil and solid waste after the final rinsing.
  • the concentration of the inclusion solution of each batch of the output material is stable, and the multi-stage intermittent countercurrent rinsing, the concentration of the inclusion solution of each batch of the output material is fluctuating. That is, the concentration continues to rise until the upper limit is reached, the final rinse is replaced with clean water, and then the concentration is steeped to a minimum, and then the concentration is continuously increased until the final rinse is replaced next time.
  • the regeneration cycle system has the following characteristics:
  • the system receives stream B, stream J, chemically or physically treats it to reduce the concentration of pollutants, and outputs regenerated eluent stream D, regenerating rinsing liquid stream R, and solution phase to the outside of the system.
  • the chemical leaching separation method for the high concentration, full circulation soil and solid waste in the solid waste provided by the embodiment has the following beneficial effects:
  • the mass of pollutants to be removed per unit time is a fixed value. Due to the high concentration of pollutants in the eluate produced in the process of the present invention, it is necessary to remove the pollutants through the regeneration cycle system. The liquid flow rate is greatly reduced, and the higher concentration of pollutants is also generally beneficial to improve the removal efficiency of the pollutants.
  • the countercurrent rinsing process system of the invention has a high concentration of the eluate and a small volume, and all of them enter the regenerative circulation system, thereby avoiding the phenomenon of secondary pollution caused by the discharge of the low concentration rinsing wastewater, and the environmental benefits are good.
  • the present embodiment provides a separation system suitable for the chemical leaching separation method of the above-mentioned high-concentration, full-circulation soil and solid waste pollutants, which is mainly composed of a conveying device 2, a solid-liquid separation device 3, The reverse rinsing device 4, the reverse osmosis device 5, the pollutant extracting device 6 and the chemical leaching device 1 for containing the eluent; wherein the chemical leaching device 1 is respectively provided for detecting the pollutant in the eluent a concentration detector 11 for concentration and a volume detector 12 for detecting the volume of the eluent, the solid output end of the chemical eluent device 1 is connected to the input end of the transport device 2, and the output end of the transport device 2 and the solid-liquid separation device 3 The input end is connected, the solid output end of the solid-liquid separation device 3 is connected to the solid input end of the countercurrent rinsing device 4 through the pipeline 7, and the pipeline 7 is provided with a valve 71, the
  • the input end of the pollutant extraction device 6 is connected to the liquid output end of the chemical elution device 1, and the liquid output end of the pollutant extraction device 6 is connected to the liquid input end of the chemical elution device 1, and the output end of the concentration detector 11 is The control end of the contaminant extraction device 6 is connected, and the output of the volume detector 12 is connected to the control end of the reverse osmosis device 5.
  • the specific working process of the above separation system is as follows: the soil or solid waste to be treated is input into the chemical leaching device 1 for chemical leaching, and the pollutants in the soil or solid waste are reacted with the eluent in the eluent to dissolve In the eluent, some of the contaminants remain in the eluent, and some of the contaminants are present in the solution mixed with the soil or solid waste, and then the washed soil or solid waste is transported through the conveying device 2 to In the solid-liquid separation device 3, the soil or solid waste after leaching is subjected to solid-liquid separation to reduce the content of the solution contained in the soil or solid waste, thereby reducing the content of pollutants in the soil or solid waste, and the solid-liquid separation The liquid is returned to the chemical leaching device 1, and the solid-liquid separated solids are sent to the countercurrent rinsing device 4 for countercurrent rinsing to remove residual contaminants in the soil or solid waste until the doping solution in the soil or solid waste
  • the pollutants contained in the solution reach the
  • Part of the eluent output in the eluent device 1 is subjected to contamination extraction by the contaminant extraction device 6, and the eluent after extracting the contaminant is returned to the chemical eluent device 1 to achieve a reduction in the concentration of the contaminant.
  • the detector 12 detects that the volume of the eluent in the chemical eluent device 1 exceeds the set constant value, the reverse osmosis device 5 is activated to output a part of the eluent in the chemical eluent device 1 to perform reverse osmosis to form reverse osmosis.
  • the concentrated solution is returned to the chemical leaching device 1 to reduce the volume of the eluent in the chemical leaching device 1, and the permeate formed by the reverse osmosis is clean water and sent to the countercurrent rinsing device 4 as a fresh rinsing liquid.
  • the countercurrent rinsing device 4 is composed of a plurality of countercurrent rinsing branches 41 arranged in parallel, and each of the countercurrent rinsing branches 41 is provided with a rinsing device.
  • the solid input end of the rinsing device 411 is connected to the solid output end of the solid-liquid separation device 3 through the pipeline 7, and the pipeline 7 is provided with a valve 71, and the rinsing device 411
  • the liquid input ends are respectively connected to the fresh water source and the permeate output end of the reverse osmosis device 5, and the liquid output end of the rinsing device 411 is connected to the input end of the eluate temporary storage tank 412; the output end of the eluate temporary storage tank 412 They are respectively connected to the liquid input end of the chemical rinsing device 1 and the liquid input end of the rinsing device 411 in the next countercurrent rinsing branch 41.
  • the rinsing device 411 can be a pressure filter device, which can be a mechanical pressure filter or an air pressure filter.
  • the rinsing device 411 can also be selected from the following structural design, wherein the rinsing device 411 is mainly composed of a housing 4111, a rotating chamber 4112, a first motor 4113, a stirring rod 4114, and a second motor 4115, wherein the rotating chamber 4112 is The through hole is disposed at intervals, the rotating chamber 4112 is rotatably mounted inside the housing 4111, the output end of the first motor 4113 is drivingly connected to the upper end of the stirring rod 4114, and the lower end of the stirring rod 4114 is inserted inside the rotating chamber 4112, the second motor The drive end of the 4115 is drivingly coupled to the rotating bin 4112.
  • the working process of the countercurrent rinsing device 4 is: the solid-liquid separation device 3 sequentially feeds the output soil or solid waste into different countercurrent rinsing branches 41 in batches, and enters the soil or solid waste in each countercurrent rinsing branch 41. Entering the rinsing device 411 for rinsing, when the rinsing device 411 selects the pressure filter device, the soil or solid waste is put into the pressure filter device, and the rinsing liquid is introduced for rinsing once. After the rinsing is finished, the washing liquid is filtered by the pressure filter device.
  • the liquid discharge is input into the filter press device in the next countercurrent rinsing branch 41 as a multiplexed rinsing liquid or returned to the chemical leaching device 1 as a multiplexed eluent according to the setting; when rinsing
  • the device 411 is in the configuration shown in FIG. 3, the soil or solid waste entering the respective countercurrent rinsing branches 41 first enters into the rotating chamber 4112 of the rinsing device 411, and after the rinsing liquid is introduced into the rotating chamber, the first A motor 4113 drives the stirring rod 4114 to perform one stirring and rinsing.
  • the second motor 4413 is started to drive the rotating chamber 4112 to rotate relative to the housing 4111, and the solid-liquid separation is performed to complete a rinsing process.
  • the rinsing liquid is introduced into the secondary rotating chamber to carry out the above-mentioned stirring rinsing and solid-liquid separation process until the concentration of the pollutants in the soil or solid waste inclusion solution in the rotating bin reaches the target of the treatment, and the rinsed soil or solid waste is input into the finished product.
  • the rinse liquid is returned to the chemical rinse device 1 as a multiplexed eluent.
  • the output end of the eluate temporary storage tank 412 is also respectively connected to the input end of the reverse osmosis device 5 and the input end of the pollutant extraction device 6, and the eluate in the eluate temporary storage tank 412 is designed by the structure. Not only can it be directly returned to the chemical leaching device 1, but it can also be processed by the reverse osmosis device 5 and the pollutant extraction device 6 and then returned to the eluent as a multiplexed eluent.
  • the concentrated solution output end of the reverse osmosis device 5 can also be connected to the input end of the contaminant extraction device 6, that is, the concentrated solution treated by the reverse osmosis device 5 is subjected to contaminant extraction by the contaminant extract extraction device 6.
  • the pollutant extraction device 6 can select unused devices respectively.
  • an electrodialysis device can be selected as the pollutant extraction device, and when the pollutant is organic, the pollutant can be used as a pollutant extraction device.
  • An extraction device is selected as the extraction device for the pollutants.
  • the pollutant extraction device shown in the figure is an anion diaphragm electrolysis device (note: the anion diaphragm electrolysis device is a kind of electrodialysis device), that is, an anion diaphragm is arranged in the middle of the electrolytic cell to divide the electrolytic cell.
  • electrolysis is performed, in which heavy metal ions are reduced and precipitated at the cathode, and the chelating agent anion in the cathode chamber is not blocked by the anion membrane and does not enter the anode chamber. It is destroyed by oxidation and decomposition, and the chelating agent anion is returned to the chemical leaching device 1 together with the aqueous solution for multiplexing to avoid the loss of the chelating agent.
  • the chemical leaching separation method and the separation system of the high-concentration and full-circulation soil pollutants provided by the present invention are used for the treatment of lead pollution.
  • the total lead content is 1000mg/kg (based on the dry soil mass, the same below)
  • the soil moisture content is 21% (the dry water content, that is, the mass ratio of water to dry soil, the same below
  • the saturated water content of the soil is 52%.
  • the treatment target is: the rate of soil treatment by 10t/h (dry basis) Continuous and stable operation, the total lead content in the treated soil is less than 150mg/kg.
  • the rinsing process of material stream A is controlled.
  • the following parameters are set for the stable operation phase of the chemical elution device (high-concentration chemical elution system): 1
  • the high concentration target value of lead in system solution C 0 is 8000 mg / L, and the chemical eluent is 0.1 mol / L concentration of EDTA - disodium solution; 2 soil in a high concentration chemical leaching system by chemical leaching, dehydration to a water content of 30%, in the form of stream A output to the countercurrent rinsing process system; 3 soil in the system has sufficient reaction time, With sufficient agitation, the total lead elution rate into the solution in the soil is guaranteed to reach 90%.
  • the regeneration cycle system is set as follows: 1
  • the system uses an anion diaphragm electrolysis method to treat the lead-containing eluent liquid stream B outputted by the high-concentration chemical elution system, and the eluate enters the cathode chamber of the anion diaphragm electrolysis cell, and the lead
  • the chelate formed with the EDTA molecule is destroyed, and the metal lead is precipitated at the cathode and removed from the system to form a pollutant stream P.
  • the EDTA molecule is blocked by the anion membrane without entering the anode chamber, being destroyed, and the EDTA-regenerated after the lead is removed.
  • the disodium solution is passed from the cathode chamber and removed from the system for use as a regenerative eluent.
  • 2 system uses reverse osmosis method to treat the eluate liquid stream, after treatment, the water without lead and chemical eluent,
  • the system is removed from the system to form a regenerating rinsing liquid stream R, used as a rinsing liquid for the rinsing system, and the concentrated solution is removed from the system;
  • 3 the regenerative eluent from the cathode chamber of the anion diaphragm electrolyzer and the concentrated solution output from the reverse osmosis unit are output together.
  • a regenerating eluent stream D is formed and reused as a eluent for a high concentration chemical leaching system.
  • the soil dry mass input into the high-concentration chemical leaching system is 10t, and the volume of the enthalpy water in the input soil is 2.1m 3 (the moisture content before treatment is 21%), which is in contact with the eluent.
  • the lead elution rate in the soil is 90%, and the lead mass M S eluted into the eluent is 9 kg; since the lead concentration of the solution set by the high concentration chemical leaching system is 8000 mg/L, the concentration is high.
  • the above total 7.2m 3 solution is reverse osmosis.
  • the rinsing liquid flow into the countercurrent rinsing system has a U volume of 4.5 m 3 , including a regenerating rinsing liquid flow V R of a volume of 3.6 m 3 , and a fresh rinsing liquid supplemented by the external process flow.
  • the flow F volume amount V F was 0.9 m 3 .
  • EDTA-disodium ie, stream C having a molar amount of 6.090405 mol was input into the system from the outside of the process, and the converted mass was 2.267092 kg.
  • the dry material flow G (ie, the final product of the process) output by the rinsing system is 10 t, and the amount of the entrained solution is 3 m 3 (water content 30%). Since the high-concentration chemical leaching system has a 90% elution efficiency for lead in the soil, the flow G contains 100 mg/kg of lead (mass 1 kg) in the solid phase; and the lead concentration C in the solution of the stream G The G value is 162.4108 mg/L, so the lead mass in the liquid phase of the stream G ⁇ is 0.48723 kg. The total mass of lead carried by stream G is 1.4873kg, and the lead content in the dry soil is 148.723mg/kg, which is less than 150mg/kg.
  • the material consumed in the process includes only 0.9m 3 fresh rinsing liquid, 2.267092kg of EDTA-disodium; the electrodialysis unit of the regeneration cycle system processes only 1.118795 m 3 , the amount of solution treated by reverse osmosis unit is 7.2m 3 ; the amount of soil treated in the process is 10t (dry basis), the lead removal rate is 85.13%, the quality of recovered metal lead is 1.48733kg, and zero discharge of waste water is realized, avoiding two The possibility of secondary pollution.

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Abstract

一种土壤、固体废物中污染物的化学淋洗分离方法及其分离系统，其中，该分离方法首先由化学淋洗步骤中的高浓度淋洗液与土壤、固体废物中的污染物发生反应，使土壤、固体废物中的污染物作为溶质溶解于淋洗液中，然后再由逆流漂洗步骤将淋洗后土壤、固体废物中夹杂溶液内作为溶质的污染物通过漂洗液部分置换出来，直至土壤、固体废物中夹杂溶液的污染物浓度等于治理目标浓度后进行排放，达到治理要求。而再生循环步骤在化学淋洗步骤以及逆流漂洗步骤的进行过程中动态启动，使土壤、固体废物在整个污染物处理过程中，保持淋洗液的体积以及淋洗液中污染物的浓度恒定，以实现稳定循环，该分离系统可实现上述的淋洗分离方法。

Description

[根据细则37.2由ISA制定的发明名称]　土壤、固体废物中污染物的化学淋洗分离方法及其分离系统
本申请要求于2017年8月21日提交中国专利局、申请号为201710719568.2、发明名称为“高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法及其分离系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明公开涉及土壤、固体废物污染治理的技术领域，尤其涉及一种高浓度、全循环式土壤污染物的化学淋洗分离方法及其分离系统。
背景技术
目前，在进行土壤污染物治理时，通常采用化学淋洗法。该方法主要是将含有淋洗剂的淋洗液与待处理的土壤或固体废物相接触，使物料中的污染物与淋洗液中的淋洗剂相互作用，通过解吸、螯合、络合、溶解或萃取等物理、化学过程，使污染物转移到淋洗液中，以实现土壤或固体废物等物料的净化。
然而，现有的化学淋洗方法在进行土壤、固体废物污染治理时，普遍存在二次污染负荷严重以及运行费用过高等问题，导致其在工程领域中不能得到大规模的推广和运用。例如：某种干重质量为10t的土壤，其污染物铅含量为1000mg/kg，修复目标是使土壤中铅含量减少至150mg/kg以下；该土壤实际含水率为21％(为干基含水率，即水与干燥土的质量比，下同)，该种土壤的饱和含水率为52％，饱和含水的土壤采用经济可行的脱水措施后，其含水率可下降至30％。为实现该修复目标，采取现有化学淋洗法进行污染的治理，具体为：采用浓度为0.01～0.1mol/L的EDTA-二钠溶液进行化学淋洗，经过1h左右的螯合反应后，土壤中原存在于固相中的铅被洗脱的效率可达90％，并以铅螯合物的溶质形态进入液相。现有化学淋洗工艺中，液固比参数(淋洗液质量与土壤质量的比值)，对于最终处理效果及废水产量具有决定性的影响，为保障处理效果，现有化学淋洗工艺通常所选择的液固比为2～10(液体与固体质量比)，因此，我们分别按照液固比为2.0、2.85以及5.4三种情况为例，来分析现有化学淋洗法工艺中废水的产生情况：
1)当选择的液固比为2.0时：
向土壤中加入体积量为20m 3、浓度为0.01～0.1mol/L的EDTA-二钠溶液进行化学淋洗，经过1h的螯合反应后，土壤中的铅被洗脱的效率为90％，进入淋洗液的铅总量为9kg、浓度为450mg/L；对化学淋洗后的土壤进行固液分离，分离后土壤含水率为30％，含水量为3m 3，分离过程形成铅含量7.65kg、浓度450mg/L的洗出液17m 3；固液分离后，土壤中残留的固相、未洗脱铅质量为1kg，土壤中残留3m 3的淋洗液中螯合态铅质量为1.35kg，固相、液相中总的铅质量为2.35kg，以土壤干重10t计，其总的铅含量为235mg/kg，未达到150mg/kg的修复目标，因此必须至少向化学淋洗后的土壤中再次引入
Figure PCTCN2018096200-appb-000001
的清水对其漂洗，漂洗后再次固液分离至土壤含水率为30％，此时土壤液相中铅质量降至0.5kg，固相、液相中总的铅质量降至1.5kg，达到150mg/kg的修复目标，同时有0.85kg的螯合态铅进入漂洗过程的洗出液中，形成铅浓度166.67mg/L的洗出液5.1m 3。综上，当采用液固比为2.0时，将产生铅浓度450mg/L的洗出液17m 3、铅浓度166.67mg/L的洗出液5.1m 3，总计洗出液废水量22.1m 3。上述废水如果再次用于其它批次的同类土壤化学淋洗，则淋洗后土壤中所残留的溶液污染物浓度将进一步升高，为实现治理目标必须引入更多的清水进行漂洗，并由此而产生更多的洗出液，因此，上述废水的复用难以实现显著减少废水量的目的。
2)当选择的液固比为4.0时：
向土壤中加入体积量为40m 3、浓度为0.01～0.1mol/L的EDTA-二钠溶液进行化学淋洗，经过1h的螯合反应后，土壤中的铅被洗脱的效率为90％，进入淋洗液的铅总量为9kg、浓度为225mg/L；对化学淋洗后的土壤进行固液分离，分离后土壤含水率为30％，含水量为3m 3，分离过程形成铅含量8.325kg、浓度225mg/L的洗出液37m 3；固液分离后，土壤中残留的固相、未洗脱铅质量为1kg，土壤中残留3m 3的淋洗液中螯合态铅质量为0.675kg，固相、液相中总的铅质量为1.675kg，以土壤干重10t计，其总的铅含量为167.5mg/kg，未达到150mg/kg的修复目标，因此必须至少向化学淋洗后的土壤中再次引入1.05m 3的清水对其漂洗，漂洗后再次固液分离至土壤含水率为30％，此时土壤液相中铅质量降至0.5kg，固相、液相中总的铅质量降至1.5kg，达到150mg/kg的修复目标，同时有0.175kg的螯合态铅进入漂洗过程的洗出液中，形成铅浓度166.67mg/L的洗出液1.05m 3。综上，当采用液固比为4.0时，将产生铅浓度225mg/L的洗出液37m 3、铅浓度166.67mg/L的洗出液1.05m 3，总计洗出液废水量38.05m 3。
3)当选择的液固比为5.4时：
向土壤中加入体积量为54m 3、浓度为0.01～0.1mol/L的EDTA-二钠溶液进行化学淋洗，经过1h的螯合反应后，土壤中的铅被洗脱的效率为90％，进入淋洗液的铅总量为9kg、浓度为166.667mg/L；对化学淋洗后的土壤进行固液分离，分离后土壤含水率为30％，含水量为3m 3，分离过程形成铅含量8.5kg、浓度166.667mg/L的洗出液51m 3；固液分离后，土壤中残留的固相、未洗脱铅质量为1kg，土壤中残留3m 3的淋洗液中螯合态铅质量为0.5kg，固相、液相中总的铅质量为1.5kg，以土壤干重10t计，其总的铅含量为150mg/kg，达到150mg/kg的修复目标。综上，当采用液固比为5.4时，总计将产生铅浓度166.667mg/L的洗出液废水量51m 3。
综上，现有化学淋洗法虽然可以实现土壤中污染物的治理，但治理过程中会产生大量含低浓度污染物的废水，如果将这些废水予以排放，势必造成严重的二次污染；如果将这些大量的低浓度废水予以治理，则会产生高昂的运行费用，在经济上又将难以承受。
因此，如何研发一种新型土壤污染物的化学淋洗分离方法，以解决上述问题，成为人们亟待解决的问题。
发明内容
鉴于此，本发明公开提供了一种高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法及其分离系统，以解决以往化学淋洗方法在进行土壤、固体废物污染治理时，普遍存在的二次污染负荷严重以及运行费用过高等问题。
本发明一方面提供了一种高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，该分离方法包括如下步骤：
化学淋洗：将待处理的土壤、固体废物放入淋洗液中进行化学淋洗后，再进行固、液分离，得淋洗后土壤、固体废物，其中，所述淋洗液的体积恒定，所述淋洗液中含有淋洗剂以及污染物，且所述淋洗液中污染物的浓度恒定，所述污染物的恒定浓度值为N倍的所述土壤、固体废物中夹杂溶液的污染物治理目标浓度；
逆流漂洗：将上述淋洗后土壤、固体废物进行逆流漂洗，直至所述土壤、固体废物中夹杂溶液的污染物浓度等于所述治理目标浓度，将逆流漂洗后的土壤、 固体废物排出，同时将逆流漂洗后的洗出液输入到化学淋洗步骤的淋洗液中，其中，所述逆流漂洗的漂洗效率为N，所述N＝逆流漂洗前土壤、固体废物中夹杂溶液的污染物浓度/逆流漂洗后土壤、固体废物中夹杂溶液的污染物浓度，且N≥2；
再生循环：当所述淋洗液中污染物的浓度大于设定的恒定浓度时，将所述淋洗液部分输出进行污染物提取，将提取污染物后的淋洗液返回到化学淋洗步骤的淋洗液中或将所述逆流漂洗后的洗出液进行污染物提取后，将提取污染物后的洗出液返回到化学淋洗步骤的淋洗液中，直至所述淋洗液中污染物浓度等于设定的恒定浓度；当所述淋洗液的体积大于设定的恒定体积时，将所述淋洗液部分输出进行反渗透，得渗透液和浓溶液或将所述逆流漂洗后的洗出液进行反渗透，得渗透液和浓溶液，并将所述浓溶液返回到化学淋洗步骤的淋洗液中，直至所述淋洗液体积等于设定的恒定体积。
优选，所述污染物为有机物，所述淋洗剂为可溶解所述有机物的有机溶液或所述污染物为难溶于水的重金属化合物，所述淋洗剂为螯合剂、酸或碱；或所述污染物为易溶于水的重金属化合物，所述淋洗剂为水。
进一步优选，所述逆流漂洗步骤中依次设置有多个漂洗槽，所述淋洗后土壤、固体废物分批次输送到第一个漂洗槽中，由第一个漂洗槽中的漂洗液进行漂洗后，将漂洗后的土壤、固体废物移送至第二个漂洗槽中，由第二个漂洗槽中的漂洗液进行漂洗，以此类推，直至土壤、固体废物经过最后一个漂洗槽中的漂洗液漂洗后移出，其中，当最后一个漂洗槽中漂洗液内污染物浓度达到污染物治理目标浓度时，将第一个漂洗槽内的漂洗液作为洗出液排出，并将第二个漂洗槽内的漂洗液移到第一个漂洗槽内作为漂洗液，以此类推，直至将最后一个漂洗槽内的漂洗液移到其上一个漂洗槽内作为漂洗液后，在最后一个漂洗槽内补入新鲜的漂洗液。
进一步优选，所述逆流漂洗步骤中设置有多条逆流漂洗支路，每条逆流漂洗支路中均设置有逆流漂洗单元；
所述淋洗后土壤、固体废物依次输入不同的逆流漂洗支路上，分别经由各所述逆流漂洗支路上的逆流漂洗单元进行多次阶段性漂洗，直至所述土壤、固体废物中夹杂溶液的污染物浓度等于治理目标浓度，所述逆流漂洗单元中每次的漂洗液体积相同；
其中，每条逆流漂洗支路上漂洗单元中第一次漂洗后的洗出液均输入到化学淋洗步骤的淋洗液中，而第M条逆流漂洗支路上漂洗单元中第W次漂洗后的洗出液均输入到第M+1条逆流漂洗支路上漂洗单元中作为该漂洗单元第W-1次漂洗的漂洗液，且所述M为大于等于1的自然数，所述W为大于等于2的自然数。
进一步优选，每次所述阶段性漂洗均依次包括：搅拌漂洗和固液分离。
进一步优选，所述再生循环步骤中，将所述渗透液输入到逆流漂洗步骤中作为漂洗液。
本发明另一方面还提供了一种高浓度、全循环式土壤中污染物的化学淋洗分离系统，所述系统适用于上述的化学淋洗分离方法，该系统包括：输送装置2、固液分离装置3、逆流漂洗装置4、反渗透装置5、污染物提取装置6以及用于盛放淋洗液的化学淋洗装置1；
所述化学淋洗装置1中分别设置有用于检测所述淋洗液中污染物浓度的浓度检测器11和用于检测所述淋洗液体积的体积检测器12，所述化学淋洗装置1的固体输出端与所述输送装置2的输入端连接；
所述输送装置2的输出端与所述固液分离装置3的输入端连接；
所述固液分离装置3的固体输出端通过管路7与所述逆流漂洗装置4的固体输入端连接，且所述管路7上设置有阀门71，所述固液分离装置3的液体输出端与所述化学淋洗装置1的液体输入端连接；
所述逆流漂洗装置4的液体输入端分别与新鲜水源以及所述反渗透装置5的渗透液输出端连接，所述逆流漂洗装置4的液体输出端与所述化学淋洗装置1的液体输入端连接；
所述反渗透装置5的输入端与所述化学淋洗装置1的液体输出端连接，所述反渗透装置5的浓溶液输出端与所述化学淋洗装置1的液体输入端连接；
所述污染物提取装置6的输入端与所述化学淋洗装置1的液体输出端连接，所述污染物提取装置6的液体输出端与所述化学淋洗装置1的液体输入端连接；
其中，所述浓度检测器11的输出端与所述污染物提取装置6的控制端连接，所述体积检测器12的输出端与所述反渗透装置5的控制端连接。
优选，所述逆流漂洗装置4由多个依次并联设置的逆流漂洗支路41构成， 且每个逆流漂洗支路41中分别设置有漂洗装置411以及洗出液暂储罐412；
其中，所述漂洗装置411的固体输入端通过管路7与固液分离装置3的固体输出端连接，且所述管路7上设置有阀门71，所述漂洗装置411的液体输入端分别与新鲜水源以及所述反渗透装置5的渗透液输出端连接，所述漂洗装置411的液体输出端与所述洗出液暂储罐412的输入端连接；
所述洗出液暂储罐412的输出端分别与所述化学淋洗装置1的液体输入端以及下一逆流漂洗支路41中漂洗装置411的液体输入端连接；
其中，所述漂洗装置411为压滤装置；
或所述漂洗装置411包括壳体4111、旋转仓4112、第一电机4113、搅拌杆4114以及第二电机4115；
所述旋转仓4112上间隔设置有通孔，所述旋转仓4112旋转安装于所述壳体4111内部；
所述第一电机4113的输出端与所述搅拌杆4114的上端驱动连接，所述搅拌杆4114的下端插设于所述旋转仓4112的内部；
所述第二电机4115的驱动端与所述旋转仓4112驱动连接。
进一步优选，所述洗出液暂储罐412的输出端还分别与所述反渗透装置5的输入端和所述污染物提取装置6的输入端连接。
进一步优选，所述反渗透装置5的浓溶液输出端还与所述污染物提取装置6的输入端连接。
进一步优选，所述污染物提取装置6为电渗析装置或萃取装置。
本发明提供的高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，主要分为化学淋洗步骤、逆流漂洗步骤以及再生循环步骤，其中，首先由化学淋洗步骤中的高浓度淋洗液与土壤、固体废物中的污染物发生反应，使土壤、固体废物中的污染物作为溶质溶解于淋洗液中，然后再由逆流漂洗步骤将淋洗后土壤、固体废物中夹杂溶液内作为溶质的污染物通过漂洗液部分置换出来，直至土壤、固体废物中夹杂溶液的污染物浓度等于治理目标浓度后进行排放，达到治理要求。而再生循环步骤在化学淋洗步骤以及逆流漂洗步骤的进行过程中动态启动，通过该再生循环步骤的启动，可使土壤、固体废物在整个污染物处理过程中， 保持淋洗液的体积以及淋洗液中污染物的浓度恒定，以实现稳定循环。本发明提供的化学淋洗分离方法，通过高浓度淋洗液的设置，一方面可将土壤、固体废物中的污染物转化为溶质溶解于淋洗液中，方便后续逆流漂洗步骤的进行；另一方面，对于任何稳定运行的去除土壤、固体废物中污染物的方法而言，其单位时间内所去除的污染物总质量为恒定值，因此，流经再生循环步骤中进行污染物提取的溶液污染物浓度、溶液流量、污染物去除率三者的乘积为恒定值，如果不考虑去除效率的差别，则溶液浓度与溶液流量呈反比例关系。本发明要求输送至污染物提取处的化学淋洗液、反渗透的浓溶液，其污染物浓度至少为治理后的所述土壤、固体废物中夹杂溶液的污染物浓度的N倍，且N≥2，其原理即是通过大幅度提升输送至污染物提取处的溶液中污染物浓度至某一高浓度值，使得污染物提取需要处理的溶液量相应大幅度减少。此外，提高溶液中污染物浓度值对于提高污染物提取的处理效率而言，通常具有积极的效应，相应地会使得污染物提取需要处理的溶液量进一步减少。此外，由于本发明使得需要污染物提取处理的溶液量大幅减少，因此，能够避免低浓度废水大量外排，相应的使得化学淋洗剂的损失量大幅减少。
本发明提供的高浓度、全循环式土壤中污染物的化学淋洗分离系统，适用于上述的化学淋洗分离方法，具有结构简单，设计合理，使用方便等优点。
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此处的附图被并入说明书中并构成本说明书的一部分，示出了符合本发明的实施例，并与说明书一起用于解释本发明的原理。
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，对于本领域普通技术人员而言，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本发明公开实施例提供的一种高浓度、全循环式土壤、固体废物中污染物化学淋洗分离方法的流程示意图；
图2为本发明公开实施例提供的一种高浓度、全循环式土壤中污染物的化学淋洗分离系统的结构示意图，其中，8表示渣、土物料斗、9表示补充淋洗剂；
图3为本发明公开实施例提供的一种高浓度、全循环式土壤中污染物的化学 淋洗分离系统的结构示意图，其中，8表示渣、土物料斗、9表示补充淋洗剂。
具体实施方式
这里将详细地对示例性实施例进行说明，其示例表示在附图中。下面的描述涉及附图时，除非另有表示，不同附图中的相同数字表示相同或相似的要素。以下示例性实施例中所描述的实施方式并不代表与本发明相一致的所有实施方式。相反，它们仅是与如所附权利要求书中所详述的、本发明的一些方面相一致的装置和方法的例子。
由于现有技术中采用的化学淋洗方法，在土壤再生或固体废物处理过程中，普遍存在产生废水量大的现象，因此会产生以下问题：1)大量废水、废液的产生将增加二次环境污染的风险；2)如果对所产生的大量废水、废液进行净化治理，其高昂的废水治理成本在经济上可能是难以承受的；3)由于废水、废液量较大，而其中所含淋洗剂浓度通常较低，因此使得回收利用淋洗剂的目标在技术上难以实现，而如果不回收淋洗剂，又将增加运行成本；4)由于废水、废液量较大，而其中所含污染物浓度通常较低，因此使得污染物的资源化回收利用在技术上难以实现；5)工艺过程导致水资源消耗过大，对于干旱地区难以承受。
本实施方案提供的高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，拟通过大幅削减工艺废水产生量，使上述相关联的问题同时得到解决，且使土壤再生或固体废物处理的经济成本得到大幅削减。
本实施方案提供的化学淋洗分离方法，包括如下步骤：
化学淋洗：将待处理的土壤、固体废物放入淋洗液中进行化学淋洗后，再进行固、液分离，得淋洗后土壤、固体废物，其中，淋洗液的体积恒定，淋洗液中含有淋洗剂以及污染物，且淋洗液中污染物的浓度恒定，污染物的恒定浓度值为N倍的土壤、固体废物中夹杂溶液的污染物治理目标浓度；
逆流漂洗：将上述淋洗后土壤、固体废物进行逆流漂洗，直至土壤、固体废物中夹杂溶液的污染物浓度等于治理目标浓度，将逆流漂洗后的土壤、固体废物排出，同时将逆流漂洗后的洗出液输入到化学淋洗步骤的淋洗液中，其中，逆流漂洗的漂洗效率为N，所述N＝逆流漂洗前土壤、固体废物中夹杂溶液的污染物浓度/逆流漂洗后土壤、固体废物中夹杂溶液的污染物浓度，且N≥2，需要指出的是，任何一个设定的漂洗系统，在稳定运行时，其漂洗效率N均为一个固定的参 数值；
再生循环：当淋洗液中污染物的浓度大于设定的恒定浓度时，将淋洗液部分输出进行污染物提取，将提取污染物后的淋洗液返回到化学淋洗步骤的淋洗液中或将逆流漂洗后的洗出液进行污染物提取后，将提取污染物后的洗出液返回到化学淋洗步骤的淋洗液中，直至淋洗液中污染物浓度等于设定的恒定浓度；当淋洗液的体积大于设定的恒定体积时，将淋洗液部分输出进行反渗透，得渗透液和浓溶液或将逆流漂洗后的洗出液进行反渗透，得渗透液和浓溶液，并将浓溶液返回到化学淋洗步骤的淋洗液中，直至淋洗液体积等于设定的恒定体积，其中，浓溶液中污染物浓度大于等于化学淋洗步骤中设定的恒定浓度值。
其中，再生循环步骤中所述设定的恒定浓度值与化学淋洗步骤中淋洗液中污染物的浓度恒定值相同；再生循环步骤中所述设定的恒定体积值与化学淋洗步骤中淋洗液的体积恒定值相同。
当待处理的土壤、固体废物中夹杂有无需要处理的石块、砾石或其他物料时，可以在化学淋洗步骤之前增加分选步骤，将无需处理的石块、砾石或其他物料予以去除，以减少后端各工艺步骤的运行负荷。
其中，当污染物为有机物时，淋洗剂为可溶解该有机物的有机溶液；当污染物为难溶于水的重金属化合物时，淋洗剂为螯合剂、酸或碱；当污染物为易溶于水的重金属化合物时，淋洗剂为水。其中，难溶于水是指在20℃条件下，100g水中溶解量小于0.1g，易溶于水是指在20℃条件下，100g水中溶解量大于10g。例如：当污染物为滴滴涕、六六六等有机物时，淋洗剂可选用正己烷等可溶解上述有机物的有机溶剂；当污染物为三氧化二铬、氧化铅等难溶于水的重金属化合物时，淋洗剂可选用EDTA二钠、草酸等螯合剂或硫酸、氢氧化钠等酸、碱；当污染物为硫酸铜等易溶于水的重金属化合物时，淋洗剂可选用水。
参见图1为本发明提供的化学淋洗分离方法的工艺流程图，其中，①化学淋洗步骤(对应于高浓度化学淋洗系统)，高浓度化学淋洗系统接收由外部送来的需要处理的土壤、固体废物等物料(料流S)，该高浓度化学淋洗系统中的淋洗液含有淋洗剂和污染物，而所谓高浓度主要是指污染物的浓度含量较高，为N倍的土壤、固体废物中夹杂溶液的污染物治理目标浓度，该高浓度淋洗液来源于新鲜淋洗液料流C以及来自其他步骤中的复用淋洗液，使需要处理的土壤、固体废物等物料与淋洗液发生相互作用，将需要处理的土壤、固体废物等物料中的污染物 作为溶质溶解与淋洗液中，然后将经过化学淋洗后的物料进行固、液分离后，将脱除部分液体后的物料以料流A的形式移出并送至逆流漂洗系统中；②逆流漂洗步骤(对应于逆流漂洗系统)，逆流漂洗系统接收高浓度化学淋洗系统输出的料流A、由外部输入的漂洗液液流U，使二者发生相互作用，然后将经过漂洗后的物料进行固、液分离后，将脱除部分液体后的物料以料流G(为工艺流程产物)的形式移出，漂洗产生的洗出液被移出形成洗出液液流H，该液流部分或全部以液流E的形式直接送至高浓度化学淋洗系统中作为复用淋洗液，剩余部分为液流J，送至再生循环系统中；③再生循环步骤(对应于再生循环系统)，该再生循环系统的启动，主要根据高浓度化学淋洗系统中淋洗液的体积以及淋洗液中污染物的浓度所决定，当淋洗液中污染物浓度超过设定的恒定浓度或淋洗液体积超过设定的恒定体积时，高浓度化学淋洗系统将输出淋洗液液流B或逆流漂洗系统输出洗出液液流J，通过再生循环系统对上述含有污染物的料流进行化学或物理的处理使其污染物浓度降低或降低料流的体积，形成再生淋洗液、再生漂洗液、与溶液相分离的污染物，再生淋洗液以液流D的形式输送至高浓度化学淋洗系统中作为淋洗液回用，再生漂洗液以液流R的形式移出再生循环系统后全部或部分输送至逆流漂洗系统作为漂洗液回用，与溶液相分离的污染物被移出至系统外形成污染物料流P。
其中，参见图1，高浓度化学淋洗系统(化学淋洗步骤)：在一定的稳定生产时间段T内，进入高浓度化学淋洗系统的料流S中有质量为M S的污染物X经过化学淋洗与淋洗剂反应，作为溶质溶解于淋洗液中，对于淋洗过程所形成的固相、液相混合物，要求控制本系统内液相中污染物X的质量浓度C X维持在一个较高的范围内，具体要求为：C X＝N*C 0，前式中：N为漂洗系统的漂洗效率，N＝C A/C G，且要求N≥2，其中C A为料流A所挟带的溶液中污染物X的浓度，C G为料流G所挟带的溶液中污染物X荣度，C 0为设定的土壤、固体废物中夹杂溶液的污染物治理目标浓度，需要指出的是，任何一个设定的漂洗系统，在稳定运行时，其漂洗效率N均为一个固定的参数值。
若要保持淋洗液体积V T恒定，具体控制方式如下：
在一定的稳定生产的时间段T内，通过工艺流程控制单位时间内进入及流出高浓度化学淋洗系统的溶液体积量相等，使得该系统内总溶液量体积稳定在某一个固定值V T。进入系统的溶液体积量包括：料流S中挟带的溶液体积量V S、由再生循环系统输送来的再生淋洗液液流D的体积量V D、由逆流漂洗系统输送来的洗 出液液流E的体积量V E；移出系统的溶液体积量包括：化学淋洗系统输出的洗出液液流B的体积量V B、化学淋洗系统输出的料流A中所挟带溶液的体积量V A，工艺流程通过控制使得：V S+V D+V E＝V B+V A，则此时高浓度化学淋洗系统内溶液体积量为某一不变的固定值V T，其中，V T的维持稳定是采用反渗透系统的启动、渗透液产生量的大小保持的。
若要保持淋洗液中污染物的浓度C X恒定，具体控制方式如下：
在高浓度化学淋洗系统中淋洗液体积为某一稳定值V T的条件下，通过工艺流程控制单位时间内进入及流出高浓度化学淋洗系统液相中的污染物X量相等，即可。当单位时间内进入量大于流出量时，污染物X在淋洗液中不断富集、C X值增高；当单位时间内进入量小于流出量时，污染物X在淋洗液中的总量不断减少、C X值降低；当单位时间内进入量等于流出量时，污染物X在溶液中的浓度C X值保持稳定。进入系统内溶液中的污染物X质量M IN包括：料流S中的污染物X被洗脱量M S、由再生循环系统输送来的再生淋洗液液流D的污染物X质量M D、由逆流漂洗系统输送来的洗出液液流E的污染物X质量M E，即M IN＝M S+M D+M E；移出系统的溶液中的污染物X质量M OUT包括：化学淋洗系统输出的洗出液液流B中的污染物X质量M B、化学淋洗系统输出的料流A中所挟带溶液中的污染物X质量M A，即M OUT＝M B+M A。系统在稳定运行期，由于此时在化学淋洗系统内淋洗液体积量为某一稳定值V T，通过工艺流程控制单位时间内进入及流出高浓度化学淋洗系统溶液中的污染物X量相等，即通过控制M IN＝M OUT，使得高浓度化学淋洗系统内溶液中的污染物X的浓度C X值稳定在N*C 0。当C X值出现波动而超过N*C 0时，通过增大液流B、液流J的体积流量或增大再生循环系统对污染物的去除率δ，使得单位时间内有更多的污染物X被再生循环系统去除，相应地使得M IN＜M OUT、高浓度化学淋洗系统内C X值降低至N*C 0；在C X值不断减少并出现或可能出现低于N*C 0的情况下，减少液流B、液流J的体积流量或减小再生循环系统对污染物的去除率δ，使得单位时间内有更少的污染物X被再生循环系统去除，相应地使得M IN＞M OUT、高浓度化学淋洗系统内C X值增加至N*C 0。
在稳定运行阶段，由于单位时间T内经由再生循环系统去除的污染物X质量是定值M DEL(M DEL＝M S-M G，式中M G为工艺流程最终产物即漂洗系统输出的料流G所挟带的溶液中污染物X质量)，故通过设定稳定运行阶段高浓度化学淋洗系统中污染物浓度C X为较高浓度的N*C 0，以减少再生循环系统需要处理的洗出液体积流量。当再生循环系统仅接受来自高浓度化学淋洗系统的淋洗液液流B时，控制 单位时间T内淋洗液液流B的体积V B＝M S/(N*C 0*δ)；当再生循环系统同时接受来自高浓度化学淋洗系统的淋洗液液流B、来自逆流漂洗系统的洗出液液流J时，按下式控制单位时间T内液流B、液流J的体积：V B*C 0*δ B+V J*C J*δ J＝M S，(式中δ B、δ J分别为再生循环系统对液流B、液流J中的污染物X去除率，C J为液流J中的污染物X质量浓度)。
对于逆流漂洗步骤，可选用多级间歇式逆流漂洗，具体为在逆流漂洗步骤中依次设置有多个漂洗槽，淋洗后土壤、固体废物分批次输送到第一个漂洗槽中，由第一个漂洗槽中的漂洗液进行漂洗后，将漂洗后的土壤、固体废物移送至第二个漂洗槽中，由第二个漂洗槽中的漂洗液进行漂洗，以此类推，直至土壤、固体废物经过最后一个漂洗槽中的漂洗液漂洗后移出，其中，当最后一个漂洗槽中漂洗液内污染物浓度达到污染物治理目标浓度时，将第一个漂洗槽内的漂洗液作为洗出液排出，并将第二个漂洗槽内的漂洗液移到第一个漂洗槽内作为漂洗液，以此类推，直至将最后一个漂洗槽内的漂洗液移到其上一个漂洗槽内作为漂洗液后，在最后一个漂洗槽内补入新鲜的漂洗液，其中，每批次中的土壤、固体废物输送量是相等的。
然而，使用上述逆流漂洗步骤漂洗后的土壤、固体废物中夹杂溶液内污染物的含量总是由低到高不断波动的情况，造成漂洗效果不稳定的问题。
参见图1，逆流漂洗系统(逆流漂洗步骤)：本实施方案提供的化学淋洗方法中优选的一种逆流漂洗方式，要求逆流漂洗系统所产生的洗出液料流H其污染物X浓度C H大于等于系统输出的料流G所挟带液体中的污染物浓度C G，即C H≥C G；系统接受的漂洗液液流U包括由工艺流程外部输入的新鲜漂洗液液流F、再生循环系统输出的再生漂洗液液流R，在一定的稳定生产时间段T内，如果高浓度化学淋洗系统和再生循环系统内由于化学反应或物理蒸发导致的溶液体积损失量V LOSS大于料流S中挟带的溶液体积量V S、且拟通过逆流漂洗系统所产生的洗出液向高浓度化学淋洗系统、再生循环系统内补偿体积量为V COMP的溶液[V COMP≤﹙V LOSS-V S﹚]时，应控制由工艺流程外部输入的新鲜漂洗液液流F其液体体积量V F等于系统输出的料流G所挟带的液体体积量V G与V COMP的和，即V F＝V G+V COMP；除前述情形外的其他情况下，应控制V F≤V G；上述工艺及参数选择的目的是：确保高浓度化学淋洗系统、再生循环系统内溶液总体积量不会由于工艺流程外部输入的V F体积量过大而出现不断增长的失稳现象。
上述实施方案中逆流漂洗步骤优选设置有多条逆流漂洗支路，每条逆流漂洗支路中均设置有逆流漂洗单元，且淋洗后土壤、固体废物分批次依次输入不同的逆流漂洗支路上，分别经由逆流漂洗支路上的逆流漂洗单元进行多次阶段性漂洗，直至土壤、固体废物中夹杂溶液的污染物浓度等于治理目标浓度，且逆流漂洗单元中每次的漂洗液体积相同；其中，每条逆流漂洗支路上漂洗单元中第一次漂洗后的洗出液均输入到化学淋洗步骤的淋洗液中，而第M条逆流漂洗支路上漂洗单元中第W次漂洗后的洗出液均输入到第M+1条逆流漂洗支路上漂洗单元中作为该漂洗单元第W-1次漂洗的漂洗液，且M为大于等于1的自然数，W为大于等于2的自然数，其中，逆流漂洗支路的个数与每一漂洗单元对一批土壤、固体废物的漂洗至达到治理目标要求的漂洗次数相等。
具体来说，参见图1，待漂洗的物料A分批次、先后分别进入逆流漂洗系统，该逆流漂洗系统包含的Q个逆流漂洗支路(Q为大于等于2的自然数)，每批次物料A的质量相等，经过漂洗后由系统移出，成为工艺流程的产物。各批次物料，按其经过工艺流程完成处理的先后顺序，依次命名为A 1、A 2、A 3……A X……(X为正整数)，每批物料按顺序依次输入到各漂洗支路上，对于任何一批次物料A X，均在漂洗系统中先后实施Q次(Q为设定的任意大于等于2的自然数)漂洗过程，称为Q级逆流漂洗系统，其中逆流漂洗系统中漂洗支路的个数与每条逆流漂洗支路上漂洗单元对一批物料的漂洗次数相等，物料A X的任意第a次(a为正整数，1＜a≤Q)漂洗过程是：将该过程所使用的漂洗液与待漂洗物料混合形成混合物，在混合过程中，待漂洗物料中的污染物质X通过溶解、扩散、稀释或化学反应等作用，以溶解物的形式均匀地分散进入混合物所含的液体中，由混合物中分离出含有污染物质X的洗出液，分离洗出液后的剩余物为物料A X第a次漂洗过程的洗后物。当a＜Q时，第a次漂洗过程的洗后物作为待漂洗物料进入物料A X的第a+1次漂洗过程；当a＝Q时，物料A X第Q次漂洗过程所产生的洗后物为逆流漂洗系统及整个工艺流程的最终产物，移出系统；物料A X在第a次(a为正整数，且1≤a＜Q)漂洗过程所使用的漂洗液为物料A X-1在第a+1次漂洗过程中所产生的洗出液；物料A X在第Q次漂洗过程所使用的漂洗液为由逆流漂洗系统外部输入的漂洗液液流F；物料A X在第1次漂洗过程中所产生的洗出液，被移出系统形成洗出液液流H；物料A X的第Q次漂洗过程所产生的洗后物被移出系统后，物料A X+Q进入物料A X原所在的漂洗单元中进行第1次清洗。
上述逆流漂洗步骤优选方案所用的逆流漂洗系统可命名为Q级差步异位换 流漂洗系统，采用上述优选方案的漂洗系统，对于所挟带溶液中含有污染物X的物料流A的漂洗过程，如果按照以下参数控制对物料流A的漂洗过程：①待漂洗的物料流A以等量均分的不同批次先后进入系统；②由外部输入的漂洗液液流U中不含污染物X；③在各批次物料的各次漂洗过程中其漂洗液体积用量均为V G的K倍，且各次漂洗过程，均分离出相同体积量的洗出液，使洗后物溶液含量均与物料流A相同(即V G＝V A)。按照以上参数控制对物料流A的漂洗过程，在稳定生产阶段，其漂洗效果如下：
①以C A与C G的比值N的值的大小表示Q级逆流漂洗系统的漂洗效果，即N Q＝C A/C G；当Q＝2(即系统为2级逆流漂洗系统)时，N 2＝(K+1) 2-K；当Q＝3(即系统为3级逆流漂洗系统)时，N 3＝(K+1)*N 2-K*(K+1)；当Q＞3时，N Q＝(K+1)*N Q-1-K*N Q-2。(式中：C A为物料流A所挟带溶液中污染物X浓度，C G为逆流漂洗系统输出料流G所挟带溶液中污染物X浓度，Q为系统设定的漂洗次数)；
②M A＝M G+M H(式中：M A为物料流A所挟带溶液中污染物X质量，M G为逆流漂洗系统输出料流G所挟带溶液中污染物X质量，M H为逆流漂洗系统输出的洗出液液流H中污染物X质量)；
③C G＝C A/N Q，C H＝C A*(N Q-1)/(K*N Q)，V H＝V U＝K*V G＝K*V A(式中：V U为输入逆流漂洗系统的漂洗液液流U体积量；V H为逆流漂洗系统输出的洗出液液流H体积量)；
通过上述逆流漂洗优选步骤的设计，每次逆流漂洗步骤中生成的需处理洗出液仅为各批次被漂洗物料第一次漂洗所产生的洗出液，而第二次乃至第Q次漂洗后的洗出液都可以重复多次利用，可大大减少产生的洗出液量，减少需处理的污水量，降低污水治理的成分，同时由于该优选方案的设计各批次被漂洗物料第一次漂洗所产生的洗出液均经过多次使用后才排出，因此其排出的洗出液中污染物浓度较高，如果再由反渗透装置进行处理，会得到含有更高浓度污染物的浓溶液，此时再送往污染物提取装置进行处理，由于污染物浓度较高，可大大减少需要处理的溶液体积量且能降低处理的难度和处理成本，更好的解决现有技术中存在的问题。
为减少每条逆流漂洗支路上漂洗单元进行的漂洗次数，作为方案的改进，每个漂洗单元在进行通常搅拌漂洗步骤之后，再进行固液分离步骤，可显著提高漂 洗单元每次漂洗的效率，进而实现达到治理目标的技术上，减少需要进行的漂洗次数，降低成本消耗。
为了节约用水，作为技术方案的改进在再生循环步骤中，将渗透液输入到逆流漂洗步骤中作为漂洗液。
上述的逆流漂洗步骤，虽然可以采用多级间歇式逆流漂洗，但最好是采用上述优选的高效逆流漂洗方法，主要原因在于，上述优选的漂洗方式与多级间歇式逆流漂洗之间有两个显著的直观的区别：
1)优选的漂洗方式分为多个漂洗支路，每个支路设置一个漂洗单元，任一漂洗单元均能够独立完成某一批次物料的漂洗，漂洗后污染物浓度达到治理目标值的要求，而多级间歇式逆流漂洗虽然也分为多个单元，但是任一批次物料都必须经过串联的若干个单元之后方使得漂洗后污染物浓度达到目标值，即仅有一个单元是对外输出最终漂洗后土壤、固体废物。
2)优选的漂洗方式在稳定运行期间，其输出的每一批物料其夹杂溶液的浓度是稳定的，而多级间歇式逆流漂洗，其输出的每批次物料其夹杂溶液的浓度是波动的，即浓度不断上升，直至达到上限后，更换末级漂洗液为清水，然后浓度陡降至最低，其后浓度又不断上升，直至下次更换末级漂洗液。
参见图1，再生循环系统具有如下特点：
①该系统接收料流B、料流J，对其进行化学或物理的处理使其污染物浓度降低，并向系统外输出再生淋洗液液流D、再生漂洗液液流R、与溶液相分离的污染物料流P；②在一定的稳定生产时间段T内，通过控制进入系统的液流(或料流)量、污染物X的去除率，使得从该系统内溶液中分离出来的污染物料流P中污染物X的质量M DEL为M S与M G的差值，即M DEL＝M S-M G(式中M G为工艺流程最终产物即漂洗系统输出的料流G所挟带的溶液中污染物X质量)；③在一定的稳定生产时间段T内，通过控制使得系统输出的再生漂洗液液流R体积量V R符合以下要求，即V R＝V S+V H-V A-V LOSS-V P。
本实施方案提供的高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，具有如下的有益效果：
1、在稳定生产阶段，单位时间内需要去除的污染物质量为固定值，由于本发明工艺流程中产生的洗出液中污染物浓度较高，使得需经由再生循环系统去除 污染物的洗出液流量大幅减少，且较高的污染物浓度通常也有利于提高污染物的去除效率。
2、本发明逆流漂洗工艺系统产生的洗出液浓度高、体积量少，且全部进入再生循环系统，避免了低浓度漂洗废水排放造成二次污染的现象，环境效益良好。
3、由于本发明工艺流程不对外排放废水，相应使得溶液中的淋洗剂流失量降至最低，能够有效的减少运行费用。
参见图2，本实施方案提供的为适用于上述高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法的分离系统，该系统主要由输送装置2、固液分离装置3、逆流漂洗装置4、反渗透装置5、污染物提取装置6以及用于盛放淋洗液的化学淋洗装置1组成；其中，化学淋洗装置1中分别设置有用于检测淋洗液中污染物浓度的浓度检测器11和用于检测淋洗液体积的体积检测器12，化学淋洗装置1的固体输出端与输送装置2的输入端连接，输送装置2的输出端与固液分离装置3的输入端连接，固液分离装置3的固体输出端通过管路7与逆流漂洗装置4的固体输入端连接，且管路7上设置有阀门71，固液分离装置3的液体输出端与化学淋洗装置1的液体输入端连接，逆流漂洗装置4的液体输入端分别与新鲜水源以及反渗透装置5的渗透液输出端连接，逆流漂洗装置4的液体输出端与化学淋洗装置1的液体输入端连接，反渗透装置5的输入端与化学淋洗装置1的液体输出端连接，反渗透装置5的浓溶液输出端与化学淋洗装置1的液体输入端连接，污染物提取装置6的输入端与化学淋洗装置1的液体输出端连接，污染物提取装置6的液体输出端与化学淋洗装置1的液体输入端连接，浓度检测器11的输出端与污染物提取装置6的控制端连接，体积检测器12的输出端与反渗透装置5的控制端连接。
上述分离系统的具体工作过程如下：待处理的土壤或固体废物输入到化学淋洗装置1中进行化学淋洗，使土壤或固体废物中的污染物与淋洗液中的淋洗剂反应，溶解于淋洗液中，部分污染物留存在淋洗液中，而部分污染物以溶质存在于夹杂在土壤或固体废物的溶液中，然后将淋洗后的土壤或固体废物通过输送装置2输送到固液分离装置3中，将淋洗后的土壤或固体废物进行固液分离，以降低土壤或固体废物中夹杂的溶液含量，进而降低土壤或固体废物中的污染物含量，固液分离后的液体返回到化学淋洗装置1中，而固液分离后的固体被输送到逆流漂洗装置4中进行逆流漂洗，以去除土壤或固体废物中残留的污染物，直至土壤 或固体废物中掺杂溶液中所含污染物达到治理目标，其中，逆流漂洗后的漂洗液会返回到化学淋洗装置1中作为复用淋洗液，而在化学淋洗装置1中分别设置有浓度检测器11和体积检测器12，当浓度检测器11检测化学淋洗装置1中的污染物浓度超过设定的恒定值时，启动污染物提取装置6将化学淋洗装置1中的部分淋洗液输出，通过污染物提取装置6进行污染提取，将提取污染物后的淋洗液返回到化学淋洗装置1中，以实现污染物浓度的降低，当体积检测器12检测化学淋洗装置1中的淋洗液体积超过设定的恒定值时，启动反渗透装置5将化学淋洗装置1中的部分淋洗液输出，进行反渗透，将反渗透形成的浓溶液返回到化学淋洗装置1中，实现化学淋洗装置1中淋洗液体积的减小，反渗透形成的渗透液为清水，送往逆流漂洗装置4作为新鲜漂洗液使用。
参见图3，上述分离系统中优选的逆流漂洗装置4的结构设计，该逆流漂洗装置4由多个依次并联设置的逆流漂洗支路41构成，且每个逆流漂洗支路41分别设置有漂洗装置411以及洗出液暂储罐412；其中，漂洗装置411的固体输入端通过管路7与固液分离装置3的固体输出端连接，且所述管路7上设置有阀门71，漂洗装置411的液体输入端分别与新鲜水源以及反渗透装置5的渗透液输出端连接，漂洗装置411的液体输出端与洗出液暂储罐412的输入端连接；洗出液暂储罐412的输出端分别与化学淋洗装置1的液体输入端以及下一逆流漂洗支路41中漂洗装置411的液体输入端连接。
其中，漂洗装置411可以选用压滤装置，可以是机械压滤，也可以是空气压滤。
参见图3，漂洗装置411还可以选用如下结构设计，其中，漂洗装置411主要由壳体4111、旋转仓4112、第一电机4113、搅拌杆4114以及第二电机4115构成，其中，旋转仓4112上间隔设置有通孔，旋转仓4112旋转安装于壳体4111内部，第一电机4113的输出端与搅拌杆4114的上端驱动连接，搅拌杆4114的下端插设于旋转仓4112的内部，第二电机4115的驱动端与旋转仓4112驱动连接。
逆流漂洗装置4的工作过程为：固液分离装置3将输出的土壤或固体废物分批次依次进入不同的逆流漂洗支路41中，进入各条逆流漂洗支路41中的土壤或固体废物首先进入到漂洗装置411进行漂洗，当漂洗装置411选用压滤装置时，土壤或固体废物放入压滤装置内，通入漂洗液进行一次漂洗，漂洗结束后，洗出 液被压滤装置压滤出来，完成一次漂洗，然后再向压滤装置内第二次通入漂洗液进行二次漂洗，漂洗结束后，洗出液被压滤装置压滤出来，完成二次漂洗，直至压滤装置中土壤或固体废物夹杂溶液的污染物浓度达到治理目标要求，将漂洗后的土壤或固体废物输入到成品盛放装置中，而每次从压滤装置输入到洗出液暂储罐412中的洗出液会根据设定输入到下一逆流漂洗支路41中的压滤装置中作为复用漂洗液或返回到化学淋洗装置1中作为复用淋洗液；当漂洗装置411为图3所示的结构时，进入各条逆流漂洗支路41中的土壤或固体废物首先进入到漂洗装置411的旋转仓4112内，并在旋转仓内通入漂洗液后，启动第一电机4113驱动搅拌杆4114进行一次搅拌漂洗，漂洗搅拌漂洗结束后，启动第二电机4413驱动旋转仓4112相对壳体4111进行旋转，进行固液分离，完成一次漂洗过程，根据治理要求，可多次向旋转仓内通入漂洗液进行上述搅拌漂洗以及固液分离过程，直至旋转仓中土壤或固体废物夹杂溶液的污染物浓度达到治理目标要求，将漂洗后的土壤或固体废物输入到成品盛放装置中，而每次从漂洗装置的壳体4111输入到洗出液暂储罐412中的洗出液会根据设定输入到下一逆流漂洗支路41中的压滤装置中作为复用漂洗液或返回到化学淋洗装置1中作为复用淋洗液。
其中，洗出液暂储罐412的输出端还分别与反渗透装置5的输入端和污染物提取装置6的输入端连接，通过该结构设计，洗出液暂储罐412中的洗出液不仅可以直接返回到化学淋洗装置1中，而且还开可以通过反渗透装置5和污染物提取装置6处理后再返回淋洗液中，作为复用淋洗液。
反渗透装置5的浓溶液输出端还可以与污染物提取装置6的输入端连接，即经过反渗透装置5处理后的浓溶液再经过污染物提取物提取装置6进行污染物的提取。
由于污染物的处理对象不同，污染物提取装置6可以分别选用不用的装置，例如：当污染物为重金属元素时，可选用电渗析装置作为污染物提取装置，而当污染物为有机物时，可选用萃取装置作为污染物的提取装置。参见图2，该图中所示的污染物提取装置为阴离子隔膜电解装置(注：阴离子隔膜电解装置是电渗析装置的一种)，即在电解池的中部设置有阴离子隔膜，将电解池划分为阴极池和阳极池，淋洗液输入到该电渗析装置中后，进行电解，其中重金属离子会在阴极被还原析出，阴极室内的螯合剂阴离子由于受到阴离子隔膜的阻隔而不会进入阳极室被氧化、分解破坏，螯合剂阴离子会连同水溶液一同返回到化学淋洗装置1中进行复用，以避免螯合剂的损失。
下面以一个具体的实施案例对本发明进行进一步的详细解释说明。
实施例1
同样以背景技术中受重金属铅污染的土壤治理为例，采用本发明提供的高浓度、全循环式土壤污染物的化学淋洗分离方法以及分离系统进行铅污染的治理。其中，该土壤处理前，其总铅含量为1000mg/kg(以干燥土壤质量计，下同)，土壤含水率为21％(为干基含水率，即水与干燥土的质量比，下同)，该土壤的饱和含水率为52％，饱和含水的土壤采用经济可行的脱水措施后，其含水率可下降至30％；治理目标是：按土壤处理量10t/h(干基)的速率连续稳定运行，使处理后的土壤中总铅含量小于150mg/kg。
对漂洗系统设定如下参数：①采用7级差步异位换流漂洗系统(Q＝7)；②化学淋洗装置输出的待漂洗的物料流A含水率为30％，以等量均分的不同批次先后进入系统；③在各批次物料的各次漂洗过程中其漂洗液体积用量均为V G的K倍(K取值1.5)，且各次漂洗过程，均分离出相同体积量的洗出液，使洗后物中溶液含量均与物料流A相同，为30％；④由系统外部输入的漂洗液液流U体积量为4.5m 3/h，其中不含污染物X。按照以上参数控制对物料流A的漂洗过程，在稳定生产阶段，其漂洗效果如下：N 7＝C A/C G＝49.25781，(式中：C A为物料流A所挟带溶液中污染物X浓度，C G为逆流漂洗系统输出料流G所挟带溶液中污染物X浓度)。
对化学淋洗装置(高浓度化学淋洗系统)稳定运行阶段设定如下参数：①系统溶液中铅的高浓度目标值C 0为8000mg/L，化学淋洗剂采用0.1mol/L浓度的EDTA-二钠溶液；②土壤在高浓度化学淋洗系统内经化学淋洗、脱水至含水率30％，以料流A的形式输出至逆流漂洗工艺系统；③土壤在系统内有足够的反应时间，并进行充分的搅拌，确保土壤中进入溶液的总铅洗脱率达到90％。
对再生循环系统作如下设定：①系统采用阴离子隔膜电解法对由高浓度化学淋洗系统输出的含铅洗出液液流B进行治理，洗出液进入阴离子隔膜电解槽阴极室后，铅与EDTA分子形成的螯合物被破坏，金属铅在阴极析出并被移出系统形成污染物料流P，EDTA分子被阴离子隔膜阻隔而不会进入阳极室、被破坏，脱除铅后再生的EDTA-二钠溶液由阴极室流出、移出系统作为再生淋洗液利用。合适的选择电极参数、电压参数，使得溶液中铅的去除率达到75％；②系统采用反渗透法对由洗出液液流进行处理，处理后的不含铅及化学淋洗剂的清水，移出系统形成再生漂洗液液流R、作为漂洗液复用于漂洗系统，浓溶液移出系统；③阴离 子隔膜电解槽阴极室输出的再生淋洗液、反渗透装置输出的浓溶液一并输出系统，形成再生淋洗液液流D，作为淋洗液复用于高浓度化学淋洗系统。
在1h时长的稳定生产阶段，输入高浓度化学淋洗系统的土壤干基质量为10t，输入土壤中挟带水的体积量为2.1m 3(处理前含水率21％)，与淋洗液接触后，土壤中的铅洗脱率90％，被洗脱进入淋洗液的铅质量M S为9kg；由于高浓度化学淋洗系统设定的溶液铅浓度值为8000mg/L，故由高浓度化学淋洗系统输出的料流A其挟带的溶液中铅浓度C A值为8000mg/L，溶液体积量为V A＝3m 3(含水率30％)，溶液中铅质量M A值为24kg；采用7级差步异位换流漂洗系统对料流A进行漂洗，由于C A/C G＝49.25781，故输出的洗后物料流G其挟带的溶液中铅浓度C G值为162.4108mg/L、溶液体积量为V G＝3m 3、溶液中铅质量为0.48723kg，漂洗系统输出的洗出液液流H中铅浓度C H值为5225.059mg/L、溶液体积量为V H＝4.5m 3、铅质量M H值为23.51277kg。
在1h时长的稳定生产阶段：输入高浓度化学淋洗系统及液再生循环系统的液体体积量包括：V S(为输入土壤中挟带水的体积量，V S＝2.1m 3)、V H(为由逆流漂洗系统输出的洗出液液流H体积量，V H＝4.5m 3)；高浓度化学淋洗系统及再生循环系统输出的液体体积量包括：V A(为高浓度化学淋洗系统输出的料流A其挟带的溶液体积量，V A＝3.0m 3)、V R(由再生循环系统反渗透装置输出的再生漂洗液液流R体积量)。为确保高浓度化学淋洗系统及再生循环系统内液体体积恒定，必须使得输入输出液体体积量相同，即V R＝V S+V H-V A＝3.6m 3，为实现以上目的：将V H(4.5m 3)全部输入再生循环系统反渗透装置，并由高浓度化学淋洗系统移出2.7m 3的洗出液输入至再生循环系统的反渗透装置，以上共计7.2m 3溶液经反渗透装置处理，控制其产水率为50％，形成体积量3.6m 3的再生漂洗液液流V R输出至漂洗系统，形成体积量3.6m 3的浓溶液返回至高浓度化学淋洗系统。
在1h时长的稳定生产阶段：输入高浓度化学淋洗系统及再生循环系统内溶液中的铅质量包括：M S(为输入土壤中被洗脱的铅质量，M S＝9kg)、M H(为由漂洗系统输出的洗出液液流H中的铅质量，M H＝23.51277kg)；高浓度化学淋洗系统及再生循环系统输出的溶液中的铅质量包括：M A(为高浓度化学淋洗系统输出的料流A其挟带的溶液中的铅质量，M A＝24kg)、M P(金属铅在电解槽阴极析出并被移出系统的质量)。为确保高浓度化学淋洗系统内溶液中铅维持高浓度目标值C 0(8000mg/L)，必须使得高浓度化学淋洗系统及再生循环系统溶液中铅的输入、输出量相同，即M P＝M S+M H-M A＝8.51277kg，为实现以上目的：由高浓度化学淋洗 系统移出1.418795m 3的洗出液输入至再生循环系统电渗析装置，控制其铅的去除率达到75％，此时在电解槽阴极析出并被移出系统的金属铅质量M P为8.51277kg。
在1h时长的稳定生产阶段：输入逆流漂洗系统的漂洗液液流U体积量为4.5m 3，其中包括体积量3.6m 3的再生漂洗液液流V R，由工艺流程外部补充的新鲜漂洗液液流F体积量V F为0.9m 3。
在1h时长的稳定生产阶段，由高浓度化学淋洗系统输出的料流A其挟带的溶液中EDTA摩尔浓度值CAE为0.1mol/L，溶液体积量为V A＝3m 3(含水率30％)，漂洗系统对料流A进行漂洗后，漂洗效果值N 7＝49.25781，故输出的洗后物料流G其挟带的溶液中EDTA摩尔浓度值CGE为0.00203mol/L、溶液体积量为V G＝3m 3、溶液中EDTA摩尔量为6.090405mol。为维持高浓度化学淋洗系统内淋洗药剂的浓度值，由工艺流程外部向该系统内输入摩尔量为6.090405mol的EDTA-二钠(即料流C)，其折算质量为2.267092kg。
在1h时长的稳定生产阶段，漂洗系统输出的洗后物料流G(即工艺流程最终产物)干基质量为10t，挟带溶液量为3m 3(含水率30％)。由于高浓度化学淋洗系统对土壤中铅的洗脱效率为90％，故料流G其固相中含有100mg/kg的铅(质量1kg)；料流G其挟带的溶液中铅浓度C G值为162.4108mg/L，故料流G挟带的液相中铅质量为0.48723kg。料流G所挟带的铅的总质量为1.48723kg，折算干基土壤中的铅含量为148.723mg/kg，达到小于150mg/kg的治理目标。
综上，在1h时长的稳定生产阶段：工艺流程所消耗的物料仅包括0.9m 3新鲜漂洗液、2.267092kg的EDTA-二钠；再生循环系统电渗析装置所处理的洗出液量仅为1.418795m 3，反渗透装置处理溶液量为7.2m 3；工艺流程处理土壤量10t(干基)，铅去除率达到85.13％，回收金属铅质量为1.48723kg，且实现了废水零排放，避免了二次污染的可能。
本领域技术人员在考虑说明书及实践这里公开的发明后，将容易想到本发明的其它实施方案。本申请旨在涵盖本发明的任何变型、用途或者适应性变化，这些变型、用途或者适应性变化遵循本发明的一般性原理并包括本发明未公开的本技术领域中的公知常识或惯用技术手段。说明书和实施例仅被视为示例性的，本发明的真正范围和精神由权利要求指出。
应当理解的是，本发明并不局限于上面已经描述并在附图中示出的精确结构，并且可以在不脱离其范围进行各种修改和改变。本发明的范围仅由所附的权 利要求来限制。

Claims (10)

  1. 一种高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，其特征在于，包括如下步骤：
    化学淋洗：将待处理的土壤、固体废物放入淋洗液中进行化学淋洗后，再进行固、液分离，得淋洗后土壤、固体废物，其中，所述淋洗液的体积恒定，所述淋洗液中含有淋洗剂以及污染物，且所述淋洗液中污染物的浓度恒定，所述污染物的恒定浓度值为N倍的所述土壤、固体废物中夹杂溶液的污染物治理目标浓度；
    逆流漂洗：将上述淋洗后土壤、固体废物进行逆流漂洗，直至所述土壤、固体废物中夹杂溶液的污染物浓度等于所述治理目标浓度，将逆流漂洗后的土壤、固体废物排出，同时将逆流漂洗后的洗出液输入到化学淋洗步骤的淋洗液中，其中，所述逆流漂洗的漂洗效率为N，所述N＝逆流漂洗前土壤、固体废物中夹杂溶液的污染物浓度/逆流漂洗后土壤、固体废物中夹杂溶液的污染物浓度，且N≥2；
    再生循环：当所述淋洗液中污染物的浓度大于设定的恒定浓度时，将所述淋洗液部分输出进行污染物提取，将提取污染物后的淋洗液返回到化学淋洗步骤的淋洗液中或将所述逆流漂洗后的洗出液进行污染物提取后，将提取污染物后的洗出液返回到化学淋洗步骤的淋洗液中，直至所述淋洗液中污染物浓度等于设定的恒定浓度；当所述淋洗液的体积大于设定的恒定体积时，将所述淋洗液部分输出进行反渗透，得渗透液和浓溶液或将所述逆流漂洗后的洗出液进行反渗透，得渗透液和浓溶液，并将所述浓溶液返回到化学淋洗步骤的淋洗液中，直至所述淋洗液体积等于设定的恒定体积。
  2. 根据权利要求1所述高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，其特征在于，所述污染物为有机物，所述淋洗剂为可溶解所述有机物的有机溶液或所述污染物为难溶于水的重金属化合物，所述淋洗剂为螯合剂、酸或碱；或所述污染物为易溶于水的重金属化合物，所述淋洗剂为水。
  3. 根据权利要求1所述高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，其特征在于，所述逆流漂洗步骤中依次设置有多个漂洗槽，所述淋洗后土壤、固体废物分批次输送到第一个漂洗槽中，由第一个漂 洗槽中的漂洗液进行漂洗后，将漂洗后的土壤、固体废物移送至第二个漂洗槽中，由第二个漂洗槽中的漂洗液进行漂洗，以此类推，直至土壤、固体废物经过最后一个漂洗槽中的漂洗液漂洗后移出，其中，当最后一个漂洗槽中漂洗液内污染物浓度达到污染物治理目标浓度时，将第一个漂洗槽内的漂洗液作为洗出液排出，并将第二个漂洗槽内的漂洗液移到第一个漂洗槽内作为漂洗液，以此类推，直至将最后一个漂洗槽内的漂洗液移到其上一个漂洗槽内作为漂洗液后，在最后一个漂洗槽内补入新鲜的漂洗液。
  4. 根据权利要求1所述高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，其特征在于，所述逆流漂洗步骤中设置有多条逆流漂洗支路，每条逆流漂洗支路中均设置有逆流漂洗单元；
    所述淋洗后土壤、固体废物依次输入不同的逆流漂洗支路上，分别经由各所述逆流漂洗支路上的逆流漂洗单元进行多次阶段性漂洗，直至所述土壤、固体废物中夹杂溶液的污染物浓度等于治理目标浓度，所述逆流漂洗单元中每次的漂洗液体积相同；
    其中，每条逆流漂洗支路上漂洗单元中第一次漂洗后的洗出液均输入到化学淋洗步骤的淋洗液中，而第M条逆流漂洗支路上漂洗单元中第W次漂洗后的洗出液均输入到第M+1条逆流漂洗支路上漂洗单元中作为该漂洗单元第W-1次漂洗的漂洗液，且所述M为大于等于1的自然数，所述W为大于等于2的自然数。
  5. 根据权利要求4所述高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，其特征在于，每次所述阶段性漂洗均依次包括：搅拌漂洗和固液分离。
  6. 根据权利要求1所述高浓度、全循环式土壤、固体废物中污染物的化学淋洗分离方法，其特征在于，所述再生循环步骤中，将所述渗透液输入到逆流漂洗步骤中作为漂洗液。
  7. 一种高浓度、全循环式土壤中污染物的化学淋洗分离系统，所述系统适用于权利要求1～6所述的化学淋洗分离方法，其特征在于，所述系统包括：输送装置(2)、固液分离装置(3)、逆流漂洗装置(4)、反渗透装置(5)、污染物提取装置(6)以及用于盛放淋洗液的化学淋洗装置(1)；
    所述化学淋洗装置(1)中分别设置有用于检测所述淋洗液中污染物浓度的浓度检测器(11)和用于检测所述淋洗液体积的体积检测器(12)，所 述化学淋洗装置(1)的固体输出端与所述输送装置(2)的输入端连接；
    所述输送装置(2)的输出端与所述固液分离装置(3)的输入端连接；
    所述固液分离装置(3)的固体输出端通过管路(7)与所述逆流漂洗装置(4)的固体输入端连接，且所述管路(7)上设置有阀门(71)，所述固液分离装置(3)的液体输出端与所述化学淋洗装置(1)的液体输入端连接；
    所述逆流漂洗装置(4)的液体输入端分别与新鲜水源以及所述反渗透装置(5)的渗透液输出端连接，所述逆流漂洗装置(4)的液体输出端与所述化学淋洗装置(1)的液体输入端连接；
    所述反渗透装置(5)的输入端与所述化学淋洗装置(1)的液体输出端连接，所述反渗透装置(5)的浓溶液输出端与所述化学淋洗装置(1)的液体输入端连接；
    所述污染物提取装置(6)的输入端与所述化学淋洗装置(1)的液体输出端连接，所述污染物提取装置(6)的液体输出端与所述化学淋洗装置(1)的液体输入端连接；
    其中，所述浓度检测器(11)的输出端与所述污染物提取装置(6)的控制端连接，所述体积检测器(12)的输出端与所述反渗透装置(5)的控制端连接。
  8. 根据权利要求6所述高浓度、全循环式土壤中污染物的化学淋洗分离系统，其特征在于，所述逆流漂洗装置(4)由多个依次并联设置的逆流漂洗支路(41)构成，且每个逆流漂洗支路(41)中分别设置有漂洗装置(411)以及洗出液暂储罐(412)；
    其中，所述漂洗装置(411)的固体输入端通过管路(7)与固液分离装置(3)的固体输出端连接，且所述管路(7)上设置有阀门(71)，所述漂洗装置(411)的液体输入端分别与新鲜水源以及所述反渗透装置(5)的渗透液输出端连接，所述漂洗装置(411)的液体输出端与所述洗出液暂储罐(412)的输入端连接；
    所述洗出液暂储罐(412)的输出端分别与所述化学淋洗装置(1)的液体输入端以及下一逆流漂洗支路(41)中漂洗装置(411)的液体输入端连接；
    其中，所述漂洗装置(411)为压滤装置；
    或所述漂洗装置(411)包括壳体(4111)、旋转仓(4112)、第一电机(4113)、搅拌杆(4114)以及第二电机(4115)；
    所述旋转仓(4112)上间隔设置有通孔，所述旋转仓(4112)旋转安装于所述壳体(4111)内部；
    所述第一电机(4113)的输出端与所述搅拌杆(4114)的上端驱动连接，所述搅拌杆(4114)的下端插设于所述旋转仓(4112)的内部；
    所述第二电机(4115)的驱动端与所述旋转仓(4112)驱动连接。
  9. 根据权利要求8所述高浓度、全循环式土壤中污染物的化学淋洗分离系统，其特征在于，所述洗出液暂储罐(412)的输出端还分别与所述反渗透装置(5)的输入端和所述污染物提取装置(6)的输入端连接。
  10. 根据权利要求7所述高浓度、全循环式土壤中污染物的化学淋洗分离系统，其特征在于，所述反渗透装置(5)的浓溶液输出端还与所述污染物提取装置(6)的输入端连接。
PCT/CN2018/096200 2017-08-21 2018-07-19 土壤、固体废物中污染物的化学淋洗分离方法及其分离系统 WO2019037562A1 (zh)

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