CN115006776B - Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization - Google Patents

Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization Download PDF

Info

Publication number
CN115006776B
CN115006776B CN202210798573.8A CN202210798573A CN115006776B CN 115006776 B CN115006776 B CN 115006776B CN 202210798573 A CN202210798573 A CN 202210798573A CN 115006776 B CN115006776 B CN 115006776B
Authority
CN
China
Prior art keywords
chromium
leaching
agent
combined treatment
acid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210798573.8A
Other languages
Chinese (zh)
Other versions
CN115006776A (en
Inventor
梁彦杰
林璋
刘炜珍
伍智仁
高会芹
刘学明
李筱琴
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Central South University
Original Assignee
Central South University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Central South University filed Critical Central South University
Priority to CN202210798573.8A priority Critical patent/CN115006776B/en
Publication of CN115006776A publication Critical patent/CN115006776A/en
Application granted granted Critical
Publication of CN115006776B publication Critical patent/CN115006776B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/33—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by chemical fixing the harmful substance, e.g. by chelation or complexation
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/37—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by reduction, e.g. hydrogenation
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
    • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
    • A62D3/38—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidation; by combustion
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G37/00—Compounds of chromium
    • A—HUMAN NECESSITIES
    • A62—LIFE-SAVING; FIRE-FIGHTING
    • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
    • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
    • A62D2101/40—Inorganic substances
    • A62D2101/43—Inorganic substances containing heavy metals, in the bonded or free state
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Abstract

The invention provides a chromium-containing hazardous waste leaching detoxification and mineralization stabilization combined treatment method, which comprises the following steps: s1: adding an oxidant into the chromium slag to obtain an oxidation product, wherein the valence state of chromium in the oxidation product is hexavalent; s2: adding a leaching agent into the oxidation product, and collecting leaching solution; wherein the leaching agent comprises one or more of iminodisuccinic acid, methylglycine diacetic acid, glutamic acid N, N-diacetic acid, ethylenediamine-N, N' -disuccinic acid and disodium aspartate; s3: and adding a reducing agent and a precipitating agent into the leaching solution to obtain a chromium-containing precipitate, wherein the valence state of the chromium-containing precipitate is positive trivalent. According to the invention, hexavalent chromium is leached from the chromium slag through the leaching agent after the chromium slag is oxidized, and meanwhile, the chromium in the chromium slag is subjected to stable treatment, so that subsequent yellowing is avoided. The invention has simple operation and obvious effect, and is worth popularizing.

Description

Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization
Technical Field
The invention belongs to the field of environmental engineering, and particularly relates to a combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization.
Background
The chromium slag is industrial dangerous solid waste generated in the process of producing chromium salt and metallic chromium, 3 tons of chromium slag can be discharged when 1 ton of chromium salt is produced on average, and 7 tons of chromium slag can be discharged when 1 ton of metallic chromium is produced. The conventional chromium slag innocent treatment process is a wet detoxification process, mainly comprises water-soluble wet detoxification, salt-soluble wet detoxification, alkali-soluble wet detoxification and acid-soluble wet detoxification, and is characterized in that the reducing agent is used for reducing easily-migrated hexavalent chromium into indissolvable and difficultly-migrated trivalent chromium, so that the toxicity of the chromium slag is reduced, the general process comprises crushing, wet ball milling, acidification or alkalization treatment, reduction, neutralization and landfill of the detoxified chromium slag.
However, the existing traditional method for treating chromium slag has certain limitations:
1. the traditional wet detoxification requires a large amount of acid, alkali liquor and neutralizing agent, which is easy to cause human health damage and environmental damage, for example, the use of a large amount of concentrated sulfuric acid during the acid dissolution wet detoxification is easy to cause overhigh concentration of acid mist in workshops, thereby causing human health damage; for example, the acid and alkali liquor added in the traditional wet detoxification method have great damage to the texture structure of the soil.
In addition, the addition of a large amount of neutralizing agents easily causes a large increase in the capacity of chromium slag.
2. The traditional wet detoxification process only aims at reducing and fixing chromium, and other heavy metal elements are usually accompanied in chromium slag, so that comprehensive consideration is needed.
3. The chromium slag subjected to reduction detoxification treatment can turn yellow under the action of natural environment, trivalent chromium is oxidized into high-concentration and strong-mobility carcinogen hexavalent chromium through landfill, rain and weathering, and long-term stability of the chromium slag cannot be maintained.
4. Chelating agents are commonly used in chromium slag remediation processes to be harmful to the environment. If oxalic acid has strong irritation and strong corrosiveness, the oxalic acid has great harm to the environment and human body; EDTA heavy metal chelate is easy to dissolve in water, and is easy to cause heavy metal enrichment to cause environmental pollution.
Based on the method, a combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization is needed to be provided, so that the problems that the total chromium content in the treated chromium slag is high, unstable and easy yellowing of medium chromium ions exists, the secondary pollution of the treatment process is serious and the like are solved.
Disclosure of Invention
The invention aims to solve the problems that the total chromium content in the treated chromium slag is high, unstable and easy to turn yellow, serious secondary pollution of a treatment process and the like exist in medium chromium ions, and provides a combined treatment method for leaching and detoxifying and mineralizing chromium-containing hazardous waste, which comprises the following steps:
s1: adding an oxidant into the chromium slag to obtain an oxidation product, wherein the valence state of chromium in the oxidation product is positive hexavalent;
s2: adding a leaching agent into the oxidation product, and collecting leaching solution;
wherein the leaching agent comprises one or more of iminodisuccinic acid, methylglycine diacetic acid, glutamic acid N, N-diacetic acid, ethylenediamine-N, N' -disuccinic acid and tetrasodium diacetate;
s3: and adding a reducing agent and a precipitating agent into the leaching solution to obtain a chromium-containing precipitate, wherein the valence state of the chromium-containing precipitate is trivalent.
Further, the step S1 further comprises the steps of crushing and screening the chromium slag and stacking the crushed and screened chromium slag before the operation of adding the oxidant, wherein the particle size of the chromium slag is 30-100 mm.
Further, the oxidizing agent includes one or more of manganese dioxide, potassium permanganate, hydrous manganese oxide, and oxygen.
Further, the molar concentration of the oxidant is 0.2-0.5 mol/L, and the solid-liquid ratio of the chromium slag to the oxidant is 1: 5-10 g/mL.
Further, the oxidation step is performed under ventilation air and light conditions.
Further, the volume ratio of the tetrasodium aspartate diacetate, the methylglycine diacetate and the iminodisuccinic acid in the leaching agent is 1: 1-2: 1-2; the volume ratio of the tetrasodium aspartate diacetate to the glutamic acid N, N-diacetic iminodisuccinic acid is 1: 1-1.5: 2-2.5.
Further, the mass concentration of the eluent is 30-40 g/L, and the solid-liquid ratio of the oxidation product to the eluent is 1: 5-10 g/mL.
Further, the reducing agent comprises one or more of ferrous chloride and ferrous sulfate, the molar concentration of the reducing agent is 2.5-3.5 mmol/L, and the volume ratio of the reducing agent to the leachate is 1: 1-2.
Further, the precipitant is one or more of lime, sodium hydroxide and potassium hydroxide, the molar concentration of the precipitant is 1-3 mmol/L, and the volumes of the precipitant and the leaching solution are 1: 1-2.
Further, step S3 further includes separating the chromium-containing precipitate from the leachate after adding the reducing agent and the precipitating agent to obtain a supernatant, and recycling the supernatant as a eluent.
Compared with the prior art, the invention at least comprises the following advantages:
1. the process is efficient and harmless, firstly, the leaching agent has strong biodegradability and is environment-friendly, and the problems of insufficient contact between the agent and soil, difficult water-soil separation, large leaching solution residual quantity, large water consumption, difficult control of secondary pollution and the like in the in-situ chemical leaching process can be effectively solved by adopting an ectopic leaching mode.
And secondly, the use amount of acid and alkali liquor in the leaching process is reduced, so that the influence on the physicochemical properties of the chromium slag is minimized while the soil damage is minimized, the treated chromium slag can be further utilized, and the treated chromium slag is matched with limestone, clay and the like to fire cement, thereby generating economic benefit.
Finally, the chromium slag is first oxidized to make chromium exist in the form of chromium (VI) with stronger mobility so as to be desorbed and leached and chelated later.
2. The effect of the eluent used in the invention is as follows: on one hand, the surface tension between chromium ions and other heavy metals and chromium slag is reduced, so that the chromium ions and other heavy metals are desorbed and dissolved, and are efficiently leached out of the chromium slag, thereby reducing the heavy metal content in the soil and achieving the effect of leaching and detoxifying.
On the other hand, chromium ions in the chromium slag can be chelated in the leaching process, one part of the chelated product is leached out from the chromium slag, and the other part of the chelated product is fixed in the treated chromium slag, so that the stabilization of chromium in the chromium slag is synchronously realized, the soil is prevented from yellowing after long-term storage, and the chromium leaching toxicity of the treated chromium slag is far lower than the critical waste standard.
Finally, the pH value of the leaching solution after leaching is alkaline, which is favorable for subsequent reduction and precipitation.
3. The oxidant used in the invention has the following benefits: firstly, because the chromium slag is alkaline, a small amount of manganese-containing oxidant efficiently oxidizes the chromium slag under the catalysis of air and sunlight, and the operation is simple and the cost is low;
and secondly, manganese element can form ferrochrome manganese mineral with iron element in soil, and oxidation conditions required by mineralization are provided, so that the mineralization of the chromium slag after treatment is stable.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully, and it is apparent that the described embodiments are only some, but not all, embodiments of the present invention. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.
Moreover, the technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the embodiments, and when the technical solutions are contradictory or cannot be implemented, it should be considered that the combination of the technical solutions does not exist, and is not within the scope of protection claimed by the present invention.
Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs and to which this invention belongs, and any method, apparatus, or material of the prior art similar or identical to the methods, apparatus, or materials of the embodiments of the invention may be used to practice the invention.
The invention provides a chromium-containing hazardous waste leaching detoxification and mineralization stabilization combined treatment method, which comprises the following steps:
s1: adding an oxidant into the chromium slag to obtain an oxidation product, wherein the valence state of chromium in the oxidation product is positive hexavalent; wherein the oxidation step converts chromium (III) to highly mobile chromium (VI) for subsequent leaching.
Preferably, the step S1 further comprises the steps of crushing and screening the chromium slag and stacking the crushed and screened chromium slag before the operation of adding the oxidant, wherein the particle size of the chromium slag is 30-100 mm.
Illustratively, in a specific treatment process, chromium slag can be placed in a leaching tank, naturally piled up, piled up on the surface, a leaching guide and drainage system is arranged at the bottom, and a leaching agent spraying system is arranged at the top; wherein, leaching guide-discharge system mainly includes collecting vat and pipeline, and collecting vat and pipeline pass through the valve and connect, collect the leaching liquor through leaching guide-discharge structure and leaching agent spraying structure and discharge circulation integration for solid-liquid quick separation improves treatment effeciency.
Besides, the leaching agent spraying system can uniformly spray the leaching agent on the surface of the pile body, so that the leaching efficiency is improved.
Preferably, the oxidizing agent comprises one or more of manganese dioxide, potassium permanganate, hydrated manganese oxide and air.
The oxidizing agent may be classified into a manganese-containing oxidizing agent (e.g., manganese dioxide, potassium permanganate, hydrous manganese oxide) and a non-manganese oxidizing agent (e.g., oxygen, particularly, an oxygen-containing gas such as air) depending on whether or not the composition contains manganese element.
In some embodiments, the oxidizing agent may be a manganese-containing oxidizing agent, i.e., the oxidizing agent may be one or more of manganese dioxide, potassium permanganate, and hydrous manganese oxide.
Because the chromium slag is alkaline, a small amount of manganese-containing oxidant reacts rapidly under alkaline conditions to complete the oxidation process.
The manganese-containing oxidant also has the effect of mineralization stabilization, which means that heavy metals form stable mineral components, and compared with the action forms of adsorption, chelation, encapsulation and the like, the mineralized heavy metals are more stable and have smaller long-term release amount. However, the mineralization process has strict control on conditions and high requirements on mineralizing agents, mineralizing temperatures and the like.
The manganese can form ferromanganese minerals with iron elements in the soil, and oxidation conditions required by mineralization are provided, so that the treated chromium slag maintains a stable mineral state after landfill, and secondary pollution is avoided.
When the chromium slag is rich in manganese, the mineralization stabilizing effect can be achieved by adding a small amount of manganese-containing oxidant.
Illustratively, when the chromium slag is rich in manganese, in other embodiments, the oxidizing agent may be a non-manganese oxidizing agent, i.e., the oxidizing agent may be oxygen in air. Therefore, the chromium slag can be oxidized naturally, and an additional manganese-containing oxidant is not needed, so that the cost is saved.
Illustratively, when the chromium slag contains a level of manganese, in other embodiments, the oxidizing agent may be a mixture of a non-manganese oxidizing agent (e.g., air) and a manganese-containing oxidizing agent. Thus, the consumption of the manganese-containing oxidant is reduced, and the cost is saved.
Because the chromium slag is alkaline, a small amount of manganese-containing oxidant reacts rapidly under alkaline conditions to complete the oxidation process.
Preferably, the molar concentration of the oxidant is 0.2-0.5 mol/L, and the solid-to-liquid ratio of the chromium slag to the oxidant is 1: 5-1: 10g/mL; so that the chromium slag is completely oxidized and mineralized, and meanwhile, excessive manganese element is not doped.
Preferably, the oxidation step is performed under ventilation air and natural light conditions.
When the oxidation process is carried out under the conditions of ventilation air and natural light, the air and sunlight have direct oxidation and catalytic oxidation effects on chromium in the presence of the manganese-containing oxidant, and the oxidation process is further promoted.
S2: adding a leaching agent to the oxidation product, and collecting leaching solution. Wherein the leaching agent comprises one or more of iminodisuccinic acid, methylglycine diacetic acid, glutamic acid N, N-diacetic acid, ethylenediamine-N, N' -disuccinic acid and disodium aspartate.
Preferably, the volume ratio of the tetra sodium aspartate diacetate, the methylglycine diacetate and the iminodisuccinic acid in the leaching agent is 1: 1-2: 1-2; the volume ratio of the tetrasodium aspartate diacetate to the glutamic acid N, N-diacetic iminodisuccinic acid is 1: 1-1.5: 2-2.5.
Preferably, the mass concentration of the eluent is 30-40 g/L, and the solid-liquid ratio of the oxidation product to the eluent is 1: 5-10 g/mL.
The eluting agent can play a role in eluting and chelating fixation in the invention, and the specific mechanism is as follows:
first,: the eluting agent can chelate chromium ions and other heavy metal ions and reduce the surface tension of the chromium ions and other heavy metal ions and chromium slag, on one hand, most of chromium in the chromium slag exists in a form of chromium (VI) under the oxidation action, and the chromium (VI) is efficiently leached out of the chromium slag due to the nature and the desorption action of the eluting agent, so that the total chromium amount in the treated chromium slag is reduced; on the other hand, chromium (III) which is not oxidized in the chromium slag and chromium (VI) which is not leached out are chelated with the leaching agent, part of the chromium (III) enters the leaching solution under the action of the leaching agent, and the other part of the chromium (VI) is fixed in the treated chromium slag, so that the yellowing caused by long-term landfill in the later stage is avoided;
secondly, the leaching agent in the invention adopts environment-friendly reagents, has biodegradability, and avoids secondary pollution to soil after landfill; and the chelate product between the leaching agent and chromium ions in the treated chromium slag is stable, so that groundwater pollution and soil yellowing are prevented. It is worth mentioning that, because the chromium (III) is chelated and has stable morphology, the chromium (III) can not be separated out in the form of hexavalent chromium under the actions of long-term landfill and environmental oxidation, namely, the restoration effect of preventing the soil from yellowing is achieved.
After the leaching agent is uniformly sprayed on the surface of the chromium slag, the leaching agent can be sprayed according to the following formula 1: and adding deionized water into the chromium slag according to a solid-liquid ratio of 5-10, so that the same leaching effect is achieved and the cost is reduced.
The deionized water can be used in the process treatment after the temperature of the deionized water is raised to 80 ℃ so as to improve the chelation and leaching effects of the leaching agent.
S3: and adding a reducing agent and a precipitating agent into the leaching solution to obtain a chromium-containing precipitate, wherein the valence state of the chromium-containing precipitate is trivalent.
Preferably, the reducing agent comprises one or more of ferrous chloride and ferrous sulfate, the molar concentration of the reducing agent is 2.5-3.5 mmol/L, and the volume ratio of the reducing agent to the leachate is 1: 1-2.
The reducing agent not only can reduce hexavalent chromium into trivalent chromium which is not easy to transfer and has poor migration, but also can adjust pH value, and improves the precipitation efficiency of the subsequent precipitant.
Preferably, the precipitant is one or more of lime, sodium hydroxide and potassium hydroxide, the molar concentration of the precipitant is 1-3 mmol/L, and the volume ratio of the precipitant to the leachate is 1: 1-2.
Preferably, the step S3 further comprises separating chromium-containing precipitate from the leachate after adding the reducing agent and the precipitating agent to obtain supernatant, and recycling the supernatant as the eluent, thereby saving cost.
The detection of the combined removal stabilizing effect can be carried out regularly in a specific treatment process, and if the dangerous waste treatment standard is met, a leaching liquid discharge pipeline can be opened, and the chromium slag can be naturally drained; if the dangerous waste disposal standard is not met, the step S2 and the step S3 are continued, and the leaching is circulated until the dangerous waste disposal standard is met.
Wherein, the chromium slag can be buried back into soil after natural draining treatment or reused as building material raw material.
For a further understanding of the invention, an illustration is now given: it should also be noted that in the examples of the present invention, IDHA refers to iminodisuccinic acid, MGDA refers to methylglycine diacetic acid, GLDA refers to glutamic acid N, N-diacetic acid, EDDS refers to ethylenediamine-N, N' -disuccinic acid, ASDA-Na 4 Refers to tetrasodium aspartate diacetate.
Example 1
Taking 5g of calcium carbonate chromium slag, crushing and screening to about 30mm, adding 25ml of manganese dioxide with the mass concentration of 0.5mol/L to the slag for oxidation treatment, and according to the solid-to-liquid ratio of 1:5, adding a composite eluent (ASDA-Na) with the mass concentration of 40g/L and the volume of 25ml 4 : GLDA: idha=1: 1: 2) Spreading on the surface of the sample, and leaching the chromium slag. Collecting the leaching solution after leaching, sequentially adding 3mmol/L and 25ml FeSO into the leaching solution 4 And 1.5mmol/L NaOH, 25ml to obtain trivalent chromium precipitate and supernatant, and recycling the supernatant as eluent.
The leacheate has a chromium concentration of 47.11mg/L as measured by ICP, a total chromium concentration of 1.21 mg/L < 15 mg/L as measured by solid leaching toxicity, and a Cr (VI) concentration of 0.35 mg/L, which is far less than the toxicity leaching standard of 5 mg/L (hazardous waste identification standard leaching toxicity identification GB 5085.3-2007).
Example 2
Taking 5g of calcium carbonate chromium slag, crushing and screening to 3About 0mm, 25ml of manganese dioxide with a mass concentration of 0.5mol/L was added thereto to oxidize the solution, and a composite eluent (ASDA-Na 4: MGDA: IDHA=1:1:2) with a mass concentration of 40g/L and a volume of 25ml was sprinkled on the surface of the sample at a solid-to-liquid ratio of 1:5 to carry out elution. Collecting the leaching solution after leaching, sequentially adding 3mmol/L and 30ml FeSO into the leaching solution 4 And 1.5mmol/L,40ml Ca (OH) 2 And obtaining trivalent chromium precipitate and supernatant, and recycling the supernatant as a eluent.
The leaching rate liquid is determined by ICP, wherein the chromium concentration is 60.89mg/L, the total chromium concentration of solid leaching toxicity determination is 4.06 mg/L < 15 mg/L, the Cr (VI) concentration is 2.27mg/L, and is less than the toxicity leaching standard of 5 mg/L (the hazardous waste identification standard leaching toxicity identification GB 5085.3-2007).
Example 3
Taking 5g of calcium carbonate chromium slag, crushing and screening to about 30mm, adding 25ml of manganese dioxide with the mass concentration of 0.5mol/L into the slag to perform oxidation treatment, and mixing the manganese dioxide with the mass concentration of 40g/L and the volume of 25ml of composite eluent (ASDA-Na) according to the solid-to-liquid ratio of 1:5 4 : MGDA: idha=1: 1: 1) Sprinkling on the surface of the sample for rinsing. Collecting the leaching solution after leaching, sequentially adding 3mmol/L and 25ml FeCl into the leaching solution 2 And 1.5mol/L,40ml Ca (OH) 2 And obtaining trivalent chromium precipitate and supernatant, and recycling the supernatant as a eluent.
The leached filtrate was measured by ICP with a chromium concentration of 42.69mg/L, a total chromium concentration of 1.41 mg/L < 15 mg/L, a Cr (VI) concentration of 0.59mg/L, less than the toxic leaching standard of 5 mg/L (hazardous waste identification standard leaching toxicity identification GB 5085.3-2007) as measured by solid leaching toxicity.
Comparative example 1
Taking 5g of calcium carbonate chromium slag, crushing and screening to about 30mm, adding 25ml of manganese dioxide with the mass concentration of 0.5mol/L into the slag to perform oxidation treatment, and mixing the manganese dioxide with the mass concentration of 40g/L and the volume of 25ml of composite eluent (ASDA-Na) with the mass concentration of 1:5 and the temperature of 80 DEG C 4 : MGDA: idha=1: 1: 2) Sprinkling on the surface of the sample for rinsing. Collecting the leaching solution after leaching, and directing toAdding 3mmol/L and 30ml FeSO into the leaching solution in turn 4 And 1.5mmol/L,40ml Ca (OH) 2 To obtain trivalent chromium precipitate and supernatant.
The concentration of chromium in the leachate is measured by ICP to be 47.11mg/L, the total chromium concentration of the treated chromium slag is measured by leaching toxicity to be 1.21 mg/L and less than 15 mg/L, and the concentration of Cr (VI) is 0.35 mg/L and is far less than the toxicity leaching standard of 5 mg/L (hazardous waste identification standard leaching toxicity identification GB 5085.3-2007).
It can be seen that the other operations in example 2 are unchanged, and the chromium concentration in the leaching solution is reduced when the temperature of the composite leaching agent is changed to 80 ℃, and the total chromium content and hexavalent chromium content of the leached solid are reduced, which indicates that the high temperature is favorable for leaching detoxification and stabilization of the chromium slag by the leaching agent.
Comparative example 2
Taking 5g of calcium carbonate chromium slag, crushing and screening to about 30mm, adding 25ml of manganese dioxide with mass concentration of 0.5mol/L into the slag to perform oxidation treatment, and adding normal-temperature deionized water according to a solid-to-liquid ratio of 1:10 (g/ml) to perform leaching. Collecting the leaching solution after leaching, sequentially adding 3mmol/L and 30ml FeSO into the leaching solution 4 And 1.5mmol/L,40ml Ca (OH) 2 To obtain trivalent chromium precipitate and supernatant.
The concentration of chromium in the leachate is measured by ICP to be 78.37mg/L, the total chromium concentration of the treated chromium slag is measured by leaching toxicity to be 11.36 mg/L and less than 15 mg/L, and the concentration of Cr (VI) is 11.36 mg/L and is more than 5 mg/L of toxicity leaching standard (hazardous waste identification standard leaching toxicity identification GB 5085.3-2007).
It can be seen that the other operations in the embodiment 2 are unchanged, the total chromium content in the leaching solution and the treated chromium slag is greatly improved without adding the composite leaching agent, and besides, the hexavalent chromium content in the treated chromium slag is far higher than national standard, thus belonging to dangerous waste and not meeting the landfill requirement; the above description shows that the eluting agent can migrate hexavalent chromium from the treated chromium slag, which is beneficial to eluting and detoxifying chromium; meanwhile, the leaching agent can reduce the leaching of chromium, and further illustrates the chelating and fixing effects of the leaching agent on the chromium.
Comparative example 3
Taking 5g of calcium carbonate chromium slag, crushing and screening to about 30mm, and mixing the composite eluent (ASDA-Na) with the mass concentration of 40g/L and the volume of 25ml according to the solid-liquid ratio of 1:5 4 : MGDA: idha=1: 1: 1). Collecting the leaching solution after leaching, sequentially adding 3mmol/L and 25ml FeSO into the leaching solution 4 And 1.5mmol/L NaOH, 25ml, to give a trivalent chromium precipitate and a supernatant.
The total chromium content of the leachate is 90.34 mg/L by ICP measurement, the total chromium concentration of the treated chromium slag is 9.88 mg/L < 15 mg/L, and the Cr (VI) concentration is 9.87 mg/L & gt 5 mg/L (hazardous waste identification standard leaching toxicity identification GB 5085.3-2007).
It can be seen that the other operations in the embodiment 3 are unchanged, the manganese-containing oxidizing agent is not added, the total chromium concentration and hexavalent chromium concentration in the leaching solution and the treated chromium slag are greatly improved, which proves that the manganese-containing oxidizing agent is beneficial to leaching detoxification of chromium, and meanwhile, the leached total chromium concentration and hexavalent chromium concentration in the treated chromium slag are greatly reduced, and further shows that the mineralization stabilizing effect of the manganese-containing oxidizing agent.
In the above technical solution of the present invention, the above is only a preferred embodiment of the present invention, and therefore, the patent scope of the present invention is not limited thereto, and all the equivalent structural changes made by the content of the present invention under the technical concept of the present invention, or the direct/indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims (9)

1. The combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization is characterized by comprising the following steps of:
s1: under the illumination condition, adding an oxidant into the chromium slag to obtain an oxidation product, wherein the valence state of chromium in the oxidation product is hexavalent; wherein the oxidant comprises one or more of manganese dioxide, potassium permanganate and hydrated manganese oxide;
s2: adding a leaching agent into the oxidation product, and collecting leaching solution;
wherein the leaching agent comprises one or more of iminodisuccinic acid, methylglycine diacetic acid, glutamic acid N, N-diacetic acid, ethylenediamine-N, N' -disuccinic acid and disodium aspartate;
s3: and adding a reducing agent and a precipitating agent into the leaching solution to obtain a chromium-containing precipitate, wherein the valence state of the chromium-containing precipitate is positive trivalent.
2. The combined treatment method according to claim 1, wherein the step S1 further comprises crushing, sieving and stacking the chromium slag before the operation of adding the oxidizing agent, wherein the particle size of the chromium slag is 30-100 mm.
3. The combined treatment method according to claim 1, wherein the molar concentration of the oxidizing agent is 0.2 to 0.5mol/L, and the solid-to-liquid ratio of the chromium slag to the oxidizing agent is 1: 5-10 g/mL.
4. The combined treatment process according to claim 1, wherein the oxidation step is carried out under ventilation air conditions.
5. The combined treatment method according to claim 1, wherein the volume ratio of tetra sodium aspartate diacetate, methylglycine diacetate and iminodisuccinic acid in the leaching agent is 1: 1-2: 1-2; the volume ratio of the disodium aspartate to the glutamic acid N, N-diacetic acid to the iminodisuccinic acid is 1: 1-1.5: 2-2.5.
6. The combined treatment method according to claim 1, wherein the mass concentration of the leaching agent is 30-40 g/L, and the solid-to-liquid ratio of the oxidation product to the leaching agent is 1: 5-10 g/mL.
7. The combined treatment method according to claim 1, wherein the reducing agent comprises one or more of ferrous chloride and ferrous sulfate, the molar concentration of the reducing agent is 2.5-3.5 mmol/L, and the volume ratio of the reducing agent to the leachate is 1: 1-2.
8. The combined treatment method according to claim 1, wherein the precipitant is one or more of lime, sodium hydroxide and potassium hydroxide, the molar concentration of the precipitant is 1-3 m mol/L, and the volume ratio of the precipitant to the leachate is 1: 1-2.
9. The combined treatment process according to claim 1, wherein step S3 further comprises separating the chromium-containing precipitate from the leachate after the addition of the reducing agent and the precipitating agent to obtain a supernatant, and recycling the supernatant as a eluent.
CN202210798573.8A 2022-07-06 2022-07-06 Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization Active CN115006776B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210798573.8A CN115006776B (en) 2022-07-06 2022-07-06 Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210798573.8A CN115006776B (en) 2022-07-06 2022-07-06 Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization

Publications (2)

Publication Number Publication Date
CN115006776A CN115006776A (en) 2022-09-06
CN115006776B true CN115006776B (en) 2023-05-26

Family

ID=83077996

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210798573.8A Active CN115006776B (en) 2022-07-06 2022-07-06 Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization

Country Status (1)

Country Link
CN (1) CN115006776B (en)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102249330B (en) * 2011-04-28 2013-02-06 武汉纺织大学 Method for industrially eliminating toxic ingredients in chromium slag
GB2543076A (en) * 2015-10-07 2017-04-12 Envit Env Tech And Eng Ltd Soil and sediment remediation
CN106583436A (en) * 2016-12-16 2017-04-26 亿利首建生态科技有限公司 Leaching method for remediating hexavalent chromium contaminated soil
CN110170511B (en) * 2019-06-28 2021-03-16 招商局生态环保科技有限公司 Thermal elution method suitable for ex-situ remediation of chromium-contaminated soil
CN110846042A (en) * 2019-11-15 2020-02-28 中国科学院南京土壤研究所 Chromium slag leaving site composite heavy metal contaminated soil synergistic leacheate and application thereof
CN111215441B (en) * 2020-01-22 2022-02-22 湖南金旅环保股份有限公司 Heavy metal chromium contaminated soil remediation step-by-step leaching method

Also Published As

Publication number Publication date
CN115006776A (en) 2022-09-06

Similar Documents

Publication Publication Date Title
CN105417767A (en) Method for removing arsenic from sulfate acidic wastewater
WO1994019121A1 (en) Method of detoxification and stabilization of soils contaminated with chromium ore waste
KR101128020B1 (en) Remediation method for cyanide contaminated soil
CN102259993A (en) Water treatment method utilizing complex-ferrous-activated persulfate oxidation
CN105293775A (en) Method adopting combined technology of pre-oxidation and coagulating sedimentation to process wastewater containing thallium and ammonia-nitrogen
Akinwekomi et al. Integrated acid mine drainage treatment using Mg (OH) 2 or Mg (HCO3) 2 and Ca (OH) 2: Implications for separate removal of metals and sulphate
CN102614620A (en) Wet detoxification method of hexavalent chromium contained alkali waste residues
Devi et al. A review on spent pickling liquor
AU2014320230A1 (en) A method for the treatment of metals
CN115006776B (en) Combined treatment method for chromium-containing hazardous waste leaching detoxification and mineralization stabilization
CN101708882A (en) Treating process of waste water containing antimony
CN107265690A (en) A kind of processing method of high arsenic waste acid
CN110526311B (en) Agent for repairing organic polluted water by using green tea nano iron activated persulfate system
CN111847702B (en) Method for treating cyanide-containing high-concentration ammonium sulfite wastewater
CN114702117B (en) Method for simultaneously removing mine heavy metals and organic pollutants by utilizing iron-containing solid wastes
CN1401800A (en) Six valence chromium ion-contg. waste slag comprehensive utilization and harmless treatment method
EP3108023B1 (en) Process for reducing the amounts of zinc (zn) and lead (pb) in materials containing iron (fe)
JP5135552B2 (en) Method for producing steelmaking slag for water injection
KR100741529B1 (en) Method for treating acidic wastewater
CN114516655A (en) Method for producing copper hydroxide from circuit board waste
CN100390077C (en) Reclaiming and utilizing method of sulfuric acid production wastewater
CN113233439A (en) Composition for harmlessly treating electrolytic manganese slag and using method thereof
CN110272146A (en) The method that landfill leachate is administered into the high ferro-aluminum sludge of water factory, industrial waste coupling
CN102851504A (en) Application of caustic calcined magnesite powder to recovery of nickel and cobalt
CN103305692A (en) Leaching method of zinc sulfide concentrate

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant