CN111825302B - Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching - Google Patents

Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching Download PDF

Info

Publication number
CN111825302B
CN111825302B CN202010651061.XA CN202010651061A CN111825302B CN 111825302 B CN111825302 B CN 111825302B CN 202010651061 A CN202010651061 A CN 202010651061A CN 111825302 B CN111825302 B CN 111825302B
Authority
CN
China
Prior art keywords
sludge
bioleaching
pyrolysis
plastic processing
heavy metals
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
CN202010651061.XA
Other languages
Chinese (zh)
Other versions
CN111825302A (en
Inventor
顾卫华
白建峰
董滨
郭江山
杨敏
庄绪宁
赵静
宋小龙
苑文仪
张承龙
王景伟
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.)
Shanghai Polytechnic University
Original Assignee
Shanghai Polytechnic 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 Shanghai Polytechnic University filed Critical Shanghai Polytechnic University
Priority to CN202010651061.XA priority Critical patent/CN111825302B/en
Publication of CN111825302A publication Critical patent/CN111825302A/en
Application granted granted Critical
Publication of CN111825302B publication Critical patent/CN111825302B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/13—Treatment of sludge; Devices therefor by de-watering, drying or thickening by heating
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/02—Biological treatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/10—Treatment of sludge; Devices therefor by pyrolysis
    • 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
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W10/00—Technologies for wastewater treatment
    • Y02W10/40—Valorisation of by-products of wastewater, sewage or sludge processing

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Mechanical Engineering (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

The invention discloses a method for treating heavy metals in regenerated plastic processing sludge by combining pyrolysis and bioleaching, which comprises the following steps: firstly, pretreating collected recycled plastic processing sludge; then placing the pretreated sludge particles in a tubular furnace with a front plasma generating device, carrying out pyrolysis under the plasma generating intensity and under the protection of inert atmosphere, continuously introducing nitrogen or argon until the sludge pyrolysis slag is cooled to room temperature, and collecting the sludge pyrolysis slag for later use; adding the obtained sludge pyrolysis residue into an improved 9K culture medium in proportion, inoculating bioleaching strains, culturing for several days, filtering, washing and carrying out solid-liquid separation to obtain bioleaching residues with stable heavy metals and reaching the standard. The invention is green, efficient, stable and low in cost, and can realize the purposes of recycling heavy metals in the sludge produced by processing the recycled plastics and harmlessness of the sludge.

Description

Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching
Technical Field
The invention belongs to the technical field of recycling and harmless treatment of solid wastes, and particularly relates to a method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching.
Background
The rapid increase in demand for plastic products has led to a rapid development of the recycled plastic industry, thereby resulting in an increase in wastewater discharge during the production of recycled plastics. Therefore, the amount of sludge produced by the recycled plastic processing as a byproduct of the recycled plastic processing wastewater treatment is also exponentially increased. Because a large amount of additives, flame retardants and colorants are added in the production process of the recycled plastics, and the additives contain a large amount of heavy metals, such as zinc, copper, nickel, cadmium, chromium, lead and the like, the waste water from the processing of the recycled plastics contains high-concentration heavy metals, and finally flows into the sludge from the processing of the recycled plastics. Therefore, from the two principles of metal resource recovery and environmental protection, a green, efficient and stable technology for recycling and harmless treatment of recycled plastic processing sludge is urgently needed.
Because the recycled plastic processing sludge contains high-concentration heavy metals, the prior art means mainly considers the aspects of sludge heavy metal reduction and sludge harmlessness, and the final disposal mode comprises sludge incineration and landfill. Research shows that a large amount of fly ash is generated by sludge incineration, and the fly ash containing high-concentration heavy metals belongs to dangerous waste and has extremely strong risk to the surrounding environment. Sludge landfill causes waste of land resources and pollution of surrounding soil, underground water and surface water. In recent years, research on recycling and harmless disposal of sludge has focused on finding new alternative technologies, such as pyrolysis of sludge, which exhibit good disposal effects. Researches show that the pyrolysis of the sludge can stabilize heavy metals in the sludge, completely decompose organic matters in the sludge (no carcinogens such as dioxin is generated), and finally reduce the sludge. However, although pyrolysis can stabilize heavy metals in the recycled plastic processing sludge containing high-concentration heavy metals, the concentration of heavy metals due to decomposition of organic matters during pyrolysis causes strong environmental risk to pyrolysis residues, which brings trouble to subsequent harmless treatment (landfill).
For the treatment of heavy metals in sludge, the existing research mainly focuses on seeking co-pyrolysis substances (chemical agents or biomass or other solid wastes) with the aim of strengthening the further stabilization of heavy metals in sludge. For example, Chinese patent (CN 110092553A) reports that waste plastic particles and sludge are pyrolyzed together to solidify heavy metals in the sludge, but the problems are that the waste plastic particles may bring heavy metal impurities, and the heavy metals in the co-pyrolysis slag are eluted. Chinese patent (CN 108905965A) reports a method for preparing a heavy metal adsorbent by sludge bioleaching-pyrolysis combined treatment, but the direct bioleaching effect of sludge can be influenced by the competitive relationship between the original flora and the added strain in the sludge, and the heavy metal in the sludge can be activated by the reaction of chloride ions in a culture medium and the heavy metal in the sludge under the high-temperature condition.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a method for treating heavy metals in the recycled plastic processing sludge by combining pyrolysis and bioleaching, which is green, efficient, stable, mild in reaction condition and low in cost, and can achieve the aim of harmlessness of the recycled plastic processing sludge containing high-concentration heavy metals.
The purpose of the invention is realized by the following technical scheme:
a method for treating heavy metals in regenerated plastic processing sludge by combining pyrolysis and bioleaching comprises the following steps:
step 1: pretreating the collected recycled plastic processing sludge, including the processes of low-temperature treatment, crushing, sieving and high-temperature drying, to obtain dried base sludge particles with uniform particle size for later use;
step 2: placing the dried sludge particles obtained in the step 1 in a tubular furnace with a front plasma generating device, pyrolyzing at high temperature under certain plasma generating intensity, certain flow of inert atmosphere protection and certain heating rate and retention time, continuously introducing inert gas until sludge pyrolysis slag is cooled to room temperature, and collecting sludge pyrolysis slag for later use;
and 3, step 3: and (3) adding the sludge pyrolysis residue obtained in the step (2) into an improved 9K culture medium according to a certain solid-liquid ratio, inoculating bioleaching strains, culturing for a period of time, filtering, washing and carrying out solid-liquid separation, respectively collecting bioleaching solution and bioleaching residue, and drying the bioleaching residue to obtain recyclable bioleaching solution and heavy metal stable and up-to-standard bioleaching residue.
Further, in the step 1, the plastic processing sludge comes from sludge generated by processing recycled plastic wastewater in a plastic processing plant, and the sludge contains 4000-12000 mg/kg of zinc, 1500-3000 mg/kg of copper, 200-800 mg/kg of nickel, 1000-5000 mg/kg of lead, 20-60 mg/kg of cadmium and 500-1000 mg/kg of chromium, and the water content is 55-70%.
Further, in the step 1, the low-temperature treatment process is carried out at the temperature of 70-90 ℃, the treatment is carried out until the water content is 10-20%, the sieving is carried out by a 20-40 mesh nylon sieve, the high-temperature drying process is carried out at the temperature of 105-110 ℃, and finally the water content of the drying base sludge particles is below 5%.
Further, in the step 2, inert gas firstly passes through the action of a plasma generating device and then enters the tubular furnace, the plasma generating strength is 1000-1800 w, the inert gas is argon or nitrogen, the flow rate is 0.3-0.5L/min, the high temperature is 400-600 ℃, the heating rate is 10-20 ℃/min, and the retention time is 60-90 min.
Further, in the step 3, the solid-to-liquid ratio (w/v) is 1: 50-1: 10 g/mL.
Still further, in step 3, the modified 9K medium composition is (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O20-80 g/L, using concentrated H2SO4The pH value is adjusted.
Further, with concentrated H2SO4Adjusting the pH value of the culture medium to be 1.5-2.0.
Further, in the step 3, the bioleaching strain is acidithiobacillus ferrooxidans domesticated by pyrolysis slag with high heavy metal concentration, and the culturing period refers to bioleaching for 5-7 days.
Further, in step 3, the washing process is carried out without FeSO4·7H2O in 9K liquid medium.
Further, in step 3, the drying treatment of the biological leaching residue is carried out in an oven at the temperature of 105-.
And further, in the step 3, the biological leachate can be recycled for 3-4 times.
Further, in step 3, the heavy metal reaching the standard is within the requirements of the hazardous waste identification standard (GB 5085.3-2007).
Compared with the prior art, the invention has the following beneficial effects:
(1) the problem of stability of high-concentration heavy metal in the recycled plastic processing sludge is solved, and the recycled plastic processing sludge is converted into general industrial solid waste from the original dangerous waste.
(2) The problems of dioxin pollution caused by incineration of sludge produced by processing recycled plastics and occupation of a large amount of land resources in landfill are avoided.
(3) The method adopts a process route of low-temperature treatment, crushing, sieving and high-temperature drying for pretreating the recycled plastic processing sludge, thereby avoiding the phenomenon of difficult crushing after direct high-temperature drying.
(4) The tubular furnace with the front-mounted plasma generating device is adopted for pyrolysis, the inert gas is ionized, the reconstruction phenomenon of the heavy metal combination mode in the regenerated plastic processing sludge is accelerated, and the pyrolysis effect is improved.
(5) The sludge is firstly pyrolyzed to kill pathogens and indigenous microorganisms contained in the sludge, and in addition, organic pollutants are also decomposed in the high-temperature process, so that adverse factors (the pathogens, the indigenous microorganisms and the organic pollutants) which subsequently influence bioleaching are eliminated.
(6) Will not contain FeSO4·7H2The O9K liquid culture medium is used for the flushing process, and fresh culture solution does not need to be supplemented in the subsequent recycling process of the biological leachate.
(7) Reagent consumption is saved, and biological leachate can be recycled for 3-4 times.
Drawings
Fig. 1 is a technical route diagram of the present invention.
FIG. 2 shows a pyrolysis apparatus with a pre-plasma generator used in the present invention.
Reference numbers in the figures: 1-an inert gas; 2-a gas flow meter; 3-vacuum meter; 4-a plasma generating device; 5-a tube furnace; 6-a plasma controller; 7-a mixed gas controller; 8-tube furnace controller; 9-a vacuum cabinet; 10-tube furnace power switch; 11-a pyrolysis gas purification device; 12-pyrolysis gas vent.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, belong to the scope of protection of the invention.
Fig. 1 is a technical route diagram of the present invention.
In the embodiment, the recycled plastic processing sludge is collected from Ningbo certain plastic processing plant and is determined to have the following components: 1549.33 mg/kg of copper, 8642.94 mg/kg of zinc, 385.17 mg/kg of nickel, 47.61 mg/kg of cadmium, 175.39 mg/kg of chromium and 2518 mg/kg of lead.
In the embodiment, the pyrolysis equipment with the front-mounted plasma generating device shown in fig. 2 is used for pyrolyzing the regenerated plastic processing sludge and comprises the plasma generating device and a tubular furnace, wherein the plasma generating device is arranged in front of the tubular furnace, and during pyrolysis, atmosphere firstly passes through the plasma generating device and then enters the tubular furnace.
Example 1
Treating collected recycled plastic processing sludge at 70 ℃, crushing, sieving by a 20-mesh nylon sieve, and drying at 105 ℃ for later use; pyrolyzing in a tubular furnace with a plasma generating device under the atmosphere of 0.3L/min pure nitrogen, and adjusting the plasma generationThe green strength is 1000 w, and the pyrolysis conditions are set as follows: the final temperature is 400 ℃, the heating rate is 10 ℃/min, the retention time is 60 min, and the nitrogen is continuously introduced to cool to the room temperature to obtain sludge pyrolysis slag; adding the sludge pyrolytic residue into a modified 9K liquid culture medium at a ratio of 1 g: 50 ml, wherein the 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O20 g/L, initial pH of the culture solution of 1.5, inoculating 10% Acidithiobacillus ferrooxidans (S.) (A. f) Performing bioleaching reaction for 7 days, filtering, and respectively collecting bioleaching liquid and bioleaching residues, wherein the bioleaching liquid is recycled; solid waste leaching toxicity leaching method (HJ/T299) experiments show that: the copper leaching concentration of 15 mg/kg, the zinc leaching concentration of 28 mg/kg, the nickel leaching concentration of 3 mg/kg, the cadmium leaching concentration of 0.3 mg/kg, the chromium leaching concentration of 0.2 mg/kg and the lead leaching concentration of 1 mg/kg in the bioleaching residues do not exceed the identification standard of hazardous wastes (GB 5085.3-2007), and the fact that the regenerated plastic industrial sludge is converted into general industrial solid wastes after pyrolysis and bioleaching combined treatment is shown.
Comparative example 1
Treating collected recycled plastic processing sludge at 70 ℃, crushing, sieving by a 20-mesh nylon sieve, and drying at 105 ℃ for later use; pyrolyzing in a tubular furnace without a plasma generating device under the atmosphere of 0.3L/min pure nitrogen, and setting pyrolysis conditions as follows: the final temperature is 400 ℃, the heating rate is 10 ℃/min, the retention time is 60 min, and the nitrogen is continuously introduced to cool to the room temperature to obtain sludge pyrolysis slag; adding the sludge pyrolytic residue into a modified 9K liquid culture medium at a ratio of 1 g: 50 ml, wherein the 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O20 g/L, initial pH of the culture solution of 1.5, inoculating 10% Acidithiobacillus ferrooxidans (S.) (A. f) Bioleaching for 7 days, and filtering. Leaching the collected bioleaching residues with solid wasteToxicity (HJ/T299) test, the results show that: the copper leaching concentration of the bioleaching residue is 84 mg/kg, the zinc leaching concentration is 116 mg/kg, the nickel leaching concentration is 11 mg/kg, the cadmium leaching concentration is 0.8 mg/kg, the chromium leaching concentration is 0.9 mg/kg and the lead leaching concentration is 8 mg/kg, which exceed the identification standard of hazardous wastes (GB 5085.3-2007).
The experimental results of example 1 and comparative example 1 show that firstly, heavy metals in the recycled plastic processing sludge can be stabilized through the combined treatment of pyrolysis and bioleaching; secondly, the preposed plasma generating device is arranged in the tubular furnace, which is beneficial to the stabilization of heavy metal in the recycled plastic processing sludge.
Example 2
Treating collected recycled plastic processing sludge at 80 ℃, crushing, sieving by a 30-mesh nylon sieve, and drying at 105 ℃ for later use; pyrolyzing in a tubular furnace with a plasma generating device under the atmosphere of pure argon of 0.4L/min, adjusting the plasma generating intensity to 1400 w, and setting the pyrolysis conditions as follows: the final temperature is 500 ℃, the heating rate is 15 ℃/min, the retention time is 90 min, and the nitrogen is continuously introduced to cool to the room temperature to obtain sludge pyrolysis slag; adding the sludge pyrolytic residue into a modified 9K liquid culture medium at a ratio of 3 g to 50 ml, wherein the 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O50 g/L, the initial pH of the culture solution is 1.8, inoculating 10% acidithiobacillus ferrooxidans, performing bioleaching reaction for 6 days, filtering, and respectively collecting bioleaching solution and bioleaching residue, wherein the bioleaching solution is recycled; solid waste leaching toxicity leaching method (HJ/T299) experiments show that: the copper leaching concentration of 12 mg/kg, the zinc leaching concentration of 23 mg/kg, the nickel leaching concentration of 2.5 mg/kg, the cadmium leaching concentration of 0.2 mg/kg, the chromium leaching concentration of 0.15 mg/kg and the lead leaching concentration of 0.8 mg/kg in the bioleaching residues do not exceed the identification standard of dangerous wastes (GB 5085.3-2007), and the fact that the regenerated plastic industrial sludge is converted into general industrial solid wastes after the pyrolysis and bioleaching combined treatment is shown.
Comparative example 2
Treating collected recycled plastic processing sludge at 80 ℃, crushing, sieving by a 30-mesh nylon sieve, and drying at 105 ℃ for later use; the sludge is directly added into a modified 9K liquid culture medium in a ratio of 3 g to 50 ml, wherein the 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O50 g/L, the initial pH of the culture solution is 1.8, 10% of acidithiobacillus ferrooxidans is inoculated, bioleaching is carried out for 6 days, and filtering is carried out. Solid waste leaching toxicity leaching method (HJ/T299) experiments show that: the copper leaching concentration of 216 mg/kg, the zinc leaching concentration of 628 mg/kg, the nickel leaching concentration of 37 mg/kg, the cadmium leaching concentration of 29 mg/kg, the chromium leaching concentration of 34 mg/kg and the lead leaching concentration of 273 mg/kg in the bioleaching residue exceed the identification standard of hazardous wastes (GB 5085.3-2007).
The experimental results of example 2 and comparative example 2 show that firstly, heavy metals in the recycled plastic processing sludge can be stabilized through the combined treatment of pyrolysis and bioleaching; ② after the recycled plastic processing sludge is treated by independent bioleaching, the heavy metal dissolution risk in the bioleaching residue is larger.
Example 3
Treating collected recycled plastic processing sludge at 90 ℃, crushing, sieving by a 40-mesh nylon sieve, and drying at 105 ℃ for later use; pyrolyzing in a tubular furnace with a plasma generating device under the atmosphere of 0.5L/min pure nitrogen, adjusting the plasma generating intensity to 1800 w, and setting the pyrolysis conditions as follows: the final temperature is 600 ℃, the heating rate is 20 ℃/min, the retention time is 80 min, and the nitrogen is continuously introduced to cool to the room temperature to obtain sludge pyrolysis slag; adding the sludge pyrolytic residue into a modified 9K liquid culture medium at a ratio of 5 g: 50 ml, wherein the 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O80 g/L, initial pH of the culture solution is 2.0, 10% acidithiobacillus ferrooxidans is inoculated, and bioleaching reaction is carried out for 5 daysFiltering, and respectively collecting biological leachate and biological leachate residue, wherein the biological leachate is recycled; solid waste leaching toxicity leaching method (HJ/T299) experiments show that: the copper leaching concentration of 9 mg/kg, the zinc leaching concentration of 16 mg/kg, the nickel leaching concentration of 1.5 mg.kg, the cadmium leaching concentration of 0.15 mg.kg, the chromium leaching concentration of 0.1 mg/kg and the lead leaching concentration of 0.6 mg/kg in the bioleaching filter residues do not exceed the identification standard of hazardous wastes (GB 5085.3-2007), and the result shows that the regenerated plastic industrial sludge is converted into general industrial solid waste after the pyrolysis and bioleaching combined treatment.
Comparative example 3
Treating collected recycled plastic processing sludge at 90 ℃, crushing, sieving by a 40-mesh nylon sieve, and drying at 105 ℃ for later use; the recycled plastic processing sludge is added into a modified 9K liquid culture medium in a ratio of 5 g to 50 ml, wherein the 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O80 g/L, the initial pH of the culture solution is 2.0, 10% of acidithiobacillus ferrooxidans is inoculated, bioleaching is carried out for 5 days, and filtering and drying are carried out; and pyrolyzing the collected bioleaching residues in a tubular furnace with a plasma generating device under the pure nitrogen atmosphere of 0.5L/min, adjusting the plasma generating intensity to 1800 w, and setting the pyrolysis conditions as follows: the final temperature is 600 ℃, the heating rate is 20 ℃/min, the retention time is 80 min, and the nitrogen is continuously introduced to cool to the room temperature to obtain sludge pyrolysis slag; solid waste leaching toxicity leaching method (HJ/T299) experiments show that: the copper leaching concentration of the pyrolysis slag is 112 mg/kg, the zinc leaching concentration is 131 mg/kg, the nickel leaching concentration is 7.6 mg.kg, the cadmium leaching concentration is 0.7 mg.kg, the chromium leaching concentration is 0.6 mg/kg and the lead leaching concentration is 8.5 mg/kg, which exceed the identification standard of hazardous wastes (GB 5085.3-2007).
The experimental results of example 3 and comparative example 3 show that firstly, heavy metals in the recycled plastic processing sludge can be stabilized through the combined treatment of pyrolysis and bioleaching; secondly, the stabilization effect of the combined process of leaching the regenerated plastic on the heavy metal in the sludge produced by processing the regenerated plastic is better than that of the combined process of leaching and pyrolyzing the regenerated plastic.

Claims (6)

1. A method for treating heavy metals in regenerated plastic processing sludge by combining pyrolysis and bioleaching is characterized by comprising the following steps:
step 1: pretreating collected recycled plastic processing sludge containing high-concentration heavy metals, wherein the pretreatment comprises the processes of low-temperature treatment, crushing, sieving and high-temperature drying to obtain dried base sludge particles with uniform particle size for later use;
and 2, step: placing the dried sludge particles obtained in the step 1 in a tubular furnace with a front plasma generating device, pyrolyzing at high temperature under the protection of inert atmosphere with certain flow and certain heating rate and retention time, continuously introducing inert gas until the sludge pyrolysis slag is cooled to room temperature, and collecting sludge pyrolysis slag;
and step 3: adding the sludge pyrolysis residue obtained in the step 2 into an improved 9K culture medium according to a certain solid-to-liquid ratio, inoculating bioleaching strains, culturing for a period of time, filtering, washing, performing solid-liquid separation, respectively collecting bioleaching solution and bioleaching residue, and drying the bioleaching residue to obtain recyclable bioleaching solution and bioleaching residue which is stable in heavy metal and reaches the standard; wherein:
in the step 1, the low-temperature treatment process is carried out at the temperature of 70-90 ℃, the treatment is carried out until the water content is 10-20%, the sieving is carried out by a 20-40 mesh nylon sieve, the high-temperature drying process is carried out at the temperature of 105-110 ℃, and finally the water content of the dried sludge particles is below 5%;
in the step 2, inert gas firstly passes through the action of a plasma generating device and then enters the tubular furnace, the plasma generating intensity is 1000-1800 w, the inert gas is argon or nitrogen, the flow is 0.3-0.5L/min, the high temperature is 400-600 ℃, the heating rate is 10-20 ℃/min, and the retention time is 60-90 min;
in step 3, the improved 9K culture medium consists of (NH)4)2SO4 3 g/L、K2HPO4 0.5 g/L、KCl 0.1 g/L、MgSO4·7H2O 0.5 g/L、Ca(NO3)20.01 g/L and FeSO4·7H2O20-80 g/L, using concentrated H2SO4Adjusting the pH value;
in step 3, the washing process is carried out by using a non-FeSO solution4·7H2O9K liquid medium.
2. The method for treating heavy metals in recycled plastic processing sludge through combination of pyrolysis and bioleaching as claimed in claim 1, wherein in step 1, the recycled plastic processing sludge is sludge generated from a plastic processing plant for treating recycled plastic wastewater, and the sludge contains 4000-12000 mg/kg of zinc, 1500-3000 mg/kg of copper, 200-800 mg/kg of nickel, 1000-5000 mg/kg of lead, 20-60 mg/kg of cadmium and 500-1000 mg/kg of chromium, and has a water content of 55-70%.
3. The method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching according to claim 1, wherein in the step 3, the solid-to-liquid ratio (w/v) is 1: 50-1: 10 g/ml.
4. The method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching as claimed in claim 1, wherein in step 3, the improved 9K culture medium composition is concentrated H2SO4Adjusting the pH value of the culture medium to be 1.5-2.0.
5. The method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching as claimed in claim 1, wherein in step 3, the bioleaching strain is acidithiobacillus ferrooxidans domesticated from pyrolysis residue with high heavy metal concentration (S.) (Acidithiobacillus ferrooxidans，A. f) The culture time is 5-7 days.
6. The method for treating heavy metals in the recycled plastic processing sludge by combining pyrolysis and bioleaching as claimed in claim 1, wherein in the step 3, the drying treatment of the bioleaching residue is carried out for 5-7 h in a drying oven with the temperature of 105-110 ℃, and the heavy metals reaching the standard are within the requirements of the hazardous waste identification standard GB 5085.3-2007.
CN202010651061.XA 2020-07-08 2020-07-08 Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching Active CN111825302B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010651061.XA CN111825302B (en) 2020-07-08 2020-07-08 Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010651061.XA CN111825302B (en) 2020-07-08 2020-07-08 Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching

Publications (2)

Publication Number Publication Date
CN111825302A CN111825302A (en) 2020-10-27
CN111825302B true CN111825302B (en) 2022-06-24

Family

ID=72901303

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010651061.XA Active CN111825302B (en) 2020-07-08 2020-07-08 Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching

Country Status (1)

Country Link
CN (1) CN111825302B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6027543A (en) * 1996-06-07 2000-02-22 Shiro Yoshizaki Method for removing a heavy metal from sludge
CN101475259A (en) * 2008-10-31 2009-07-08 南开大学 Method for removing heavy metal in excess activated sludge
CN110092559A (en) * 2019-04-10 2019-08-06 浙江清风源环保科技有限公司 A kind of processing method of sludge containing heavy metal
CN110092553A (en) * 2019-04-10 2019-08-06 浙江清风源环保科技有限公司 A method of based on pyrolyzing sludge curing heavy metal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6027543A (en) * 1996-06-07 2000-02-22 Shiro Yoshizaki Method for removing a heavy metal from sludge
CN101475259A (en) * 2008-10-31 2009-07-08 南开大学 Method for removing heavy metal in excess activated sludge
CN110092559A (en) * 2019-04-10 2019-08-06 浙江清风源环保科技有限公司 A kind of processing method of sludge containing heavy metal
CN110092553A (en) * 2019-04-10 2019-08-06 浙江清风源环保科技有限公司 A method of based on pyrolyzing sludge curing heavy metal

Also Published As

Publication number Publication date
CN111825302A (en) 2020-10-27

Similar Documents

Publication Publication Date Title
CN105712733B (en) Porous biological ceramsite prepared from waste incineration fly ash and biomass pyrolysis gasification residues and preparation method thereof
CN104923153A (en) Preparation method for Canna biological carbon capable of simultaneously adsorbing ammonia nitrogen and cadmium
Hanumanthakari et al. Biomining Method to Extract Metal Components Using Computer-Printed Circuit Board E-Waste
CN111921536B (en) Novel catalytic adsorption material prepared based on natural minerals and biomass
CN109457113B (en) Method for cooperatively disposing hazardous waste in metallurgical furnace
CN111939874A (en) Method for removing tetracycline in water by using sludge-based biochar activated persulfate in synergistic manner
CN108706802B (en) Treatment method and treatment system for pollutants generated by household garbage incineration
CN111288472A (en) Controlled step pyrolysis recovery and dioxin prevention and control method for waste salt in chemical industry
CN111533125A (en) Preparation method of nitrogen-doped hierarchical pore carbon material
CN105537245A (en) Resource utilization system for rubbish fly ash
CN110983057A (en) Soot treatment method capable of realizing UPOPs synthesis retardation and low-temperature decomposition
CN113117681A (en) Method for treating industrial wastewater by enhanced Fenton
CN113751476B (en) Method for cooperative treatment and cyclic utilization of metallurgical solid waste and municipal waste incineration fly ash
CN111825302B (en) Method for treating heavy metals in recycled plastic processing sludge by combining pyrolysis and bioleaching
CN110586616A (en) Efficient inhibition method for dioxin regeneration in fly ash high-temperature thermal treatment process
CN106744952A (en) The method that sewage sludge prepares modified active coke
CN110407207B (en) High-temperature co-carbonizing agent and application thereof in recarburization and impurity solidification in carbonization process of plastic wastes
CN111495349A (en) Modified biomass charcoal catalyst based on activated sludge and preparation method thereof
CN115106058B (en) Phosphorus modified biomass charcoal, preparation method thereof and application thereof in absorbing rare earth ions in solution system
US20070231073A1 (en) Method of utilizing high-temp steam and recirculated heat source to separate mercury and crack dioxin and organic substances contained in soil
CN116078797A (en) Method for recycling biogas residues
CN201288106Y (en) Coking industry industrial wastewater comprehensive wastewater treatment system
CN114082767A (en) Method for promoting chlorination volatilization of heavy metals in fly ash generated by burning household garbage
CN110368917B (en) Method for preparing efficient adsorption material from paraffin oil decoloration waste soil and application thereof
CN109385527B (en) Method for comprehensively recovering nickel-chromium alloy

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