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CN-121992207-A - Synergistic recycling method of bromine-containing heavy metal-containing soot

CN121992207ACN 121992207 ACN121992207 ACN 121992207ACN-121992207-A

Abstract

The invention discloses a synergistic recycling method of bromine-containing and heavy metal-containing soot, and belongs to the technical field of bromine-containing and heavy metal-containing hazardous waste treatment. The method comprises the steps of S1, coordination leaching, two-stage countercurrent leaching of soot by adopting NH 4 Br solution, S2, reduction precipitation, step-by-step addition of a reducing agent to convert copper into CuBr precipitate, S3, oxidation leaching, step-by-step addition of an oxidizing agent to convert CuBr into CuBr 2 solution, S4, extraction back extraction, recovery of zinc-containing ammonia solution by using an amine extractant, S5, transformation circulation, conversion of lead into PbCO 3 slag by using carbonate, and recycling concentrated water of transformed liquid and raffinate film as NH 4 Br leaching agent. The invention realizes the in-situ recycling of bromine and the synergistic high-valued recovery of copper, zinc, lead and bromine, and has the advantages of mild process conditions, less medicament consumption, no secondary pollution, high product purity and the like.

Inventors

  • ZHAN QI
  • Luo Feihang
  • JIANG KE
  • DONG MINHUI
  • XU ZENGHUI
  • LUO YUANLING
  • WANG ZHENZHEN
  • WANG FAN

Assignees

  • 长沙环境保护职业技术学院
  • 湖南现代环境科技股份有限公司

Dates

Publication Date
20260508
Application Date
20260224

Claims (10)

  1. 1. The synergistic recycling method of the bromine-containing and heavy metal-containing soot is characterized by comprising the following steps of: S1, coordinate leaching, namely carrying out primary leaching on soot, filtering to obtain primary leaching solution and primary leaching slag, adding NH 4 Br solution into the primary leaching slag to carry out secondary leaching, controlling the liquid-solid ratio of the NH 4 Br solution to the soot to be 3-6:1, leaching pH to be 4.5-5.2, filtering to obtain secondary leaching solution and secondary leaching slag, and returning the secondary leaching solution to the primary leaching; S2, reducing and precipitating, namely adding a reducing agent I and pure water into the first-stage leaching solution, stirring and reacting, controlling the adding and reacting time to be 1-2 hours, controlling the reacting temperature to be 5-15 ℃, and the volume ratio of the pure water to the first-stage leaching solution to be 1-2:1; S3, oxidizing leaching, namely continuously adding an oxidant I into the reducing slag, stirring and reacting, and controlling the adding and reacting time to be 1-2 hours, continuously adding an oxidant II after the reaction is finished, stirring and reacting, and controlling the adding and reacting time to be 0.5-1 hour to obtain a CuBr 2 solution; S4, extraction back extraction, namely adding an amine extractant into the reduced liquid, stirring and reacting to obtain raffinate and extract, and carrying out back extraction on the extract by using an ammonia water solution to obtain a zinc-containing ammonia solution and a back extraction liquid, wherein the back extraction liquid is used as the extractant for recycling; And S5, transformation circulation, namely adding a transformation agent into the second-stage leaching slag, stirring and reacting, controlling the liquid-solid ratio of the transformation agent to the second-stage leaching slag to be 1-2:1, obtaining transformed liquid and lead slag, concentrating the raffinate through a membrane to obtain fresh water and concentrated water, recycling the fresh water as pure water to the step S2, and recycling the transformed liquid and the concentrated water as NH 4 Br solution to the step S1.
  2. 2. The synergistic recycling method of the bromine-containing heavy metal-containing soot according to claim 1, wherein the mass percentage of Cu in the soot is 15% -30%, the mass percentage of Zn is 5% -15%, the mass percentage of Br is 22% -38%, and the mass percentage of Pb is 5% -10%.
  3. 3. The method for synergistically recycling bromine-containing heavy metal-containing soot according to claim 1, wherein the molar concentration of the second leached NH 4 Br in the step S1 is 3.6-5.2 mol/L.
  4. 4. The method for the synergistic recycling of bromine-containing and heavy metal-containing soot according to claim 1, wherein the first leaching temperature in the step S1 is 35-50 ℃ and the second leaching temperature is 10-25 ℃.
  5. 5. The method for synergic recycling of bromine-containing and heavy metal-containing soot according to claim 1, wherein the reducing agent I in the step S2 is copper powder, the particle size of the copper powder is 80-250 μm, and the molar ratio of the copper powder to copper in the first-stage leaching solution is 0.5-0.7:1.
  6. 6. The method for the synergistic recycling of bromine-containing and heavy metal-containing soot according to claim 1, wherein the reducing agent II in the step S2 is ascorbic acid, and the molar ratio of the ascorbic acid to copper in the first-stage leaching solution is 0.15-0.25:1.
  7. 7. The method for synergic recycling of bromine-containing and heavy metal-containing soot according to claim 1, wherein in the step S3, the oxidant I is one or more of HBr and Br 2 , and the molar ratio of Br in the oxidant I to Cu in the reducing slag is 1-1.1:1.
  8. 8. The method for the synergistic recycling of the bromine-containing and heavy metal-containing soot according to claim 1, wherein in the step S3, the oxidant II is one or more of H 2 O 2 、O 3 , and the molar ratio of the oxidant II to Cu in the reducing slag is 0.2-0.5:1.
  9. 9. The method for synergic recycling of bromine-containing and heavy metal-containing soot according to claim 1, wherein in the step S4, the amine extractant is one of trialkyl tertiary amine and methyltrialkylammonium chloride, the extraction pH is 2.7-3.5, and the concentration of the ammonia water solution is 0.5-1 mol/L.
  10. 10. The method for synergic recycling of bromine-containing and heavy metal-containing soot according to claim 1, wherein the transforming agent in the step S5 is one or more of NH 4 HCO 3 、(NH 4 ) 2 CO 3 , and the molar ratio of C in the transforming agent to Pb in the two-stage leaching residue is 1.1-1.3:1.

Description

Synergistic recycling method of bromine-containing heavy metal-containing soot Technical Field The invention relates to a recycling method of bromine-containing and heavy metal-containing soot, and belongs to the technical field of treatment of hazardous waste containing bromine and heavy metal. Background With the rapid development of electronic information technology, the annual production of waste electronic devices (such as waste circuit boards) is continuously rising, and a great amount of bromine-containing heavy metal soot is inevitably produced in the incineration treatment process. The main components of the ash comprise high-concentration copper, zinc, lead and bromine, wherein the bromine element is mainly derived from Brominated Flame Retardant (BFRs) added in a circuit board. If the ash is improperly disposed, not only is the valuable metal resources such as copper, zinc, lead and the like seriously wasted, but also the composite pollution of soil, water and atmosphere is caused by the volatility of bromine element (such as forming HBr gas) and the biotoxicity of heavy metal, and the serious threat to the ecological environment and the human health is formed. At present, the treatment technology for bromine-containing heavy metal soot mainly depends on the traditional acid leaching or high-temperature incineration process, the existing patent multi-focus single metal recovery does not establish a cooperative circulation system of bromine elements and heavy metals, bromine resources are difficult to recycle and carry out closed-loop management, in-situ resource cooperative mechanism is lacking, a recovery path of the bromine resources and the metal resources is cracked, and the cooperative elevation of 'bromine-metal' cannot be realized. Therefore, development of a new process capable of realizing in-situ recycling of bromine (avoiding bromine resource loss) and co-high-valued recovery of heavy metals (synchronous and efficient extraction of copper, zinc and lead), construction of a closed loop circulation path of bromine, and solving of the technical problem of co-recycling of dangerous waste containing bromine and heavy metals is needed. Disclosure of Invention Aiming at the problems in the prior art, the invention aims to provide a synergic recycling method of bromine-containing and heavy metal-containing soot, which has the advantages of no need of high temperature and high pressure, mild process conditions, no secondary pollution and low medicament consumption, and can realize in-situ circulation of bromine resources and synergic high-value recovery of bromine and heavy metal. In order to achieve the above object, a first aspect of the present invention provides a method for the synergistic recycling of bromine-containing heavy metal-containing soot, comprising the steps of: S1, coordinate leaching, namely carrying out primary leaching on soot, filtering to obtain primary leaching solution and primary leaching slag, adding NH 4 Br solution into the primary leaching slag to carry out secondary leaching, controlling the liquid-solid ratio of the NH 4 Br solution to the soot to be 3-6:1, leaching pH to be 4.5-5.2, filtering to obtain secondary leaching solution and secondary leaching slag, and returning the secondary leaching solution to the primary leaching; The purpose of the coordination leaching is to realize the separation of Cu, zn and Pb by utilizing the selective leaching of NH 4 Br solution to Cu and Zn. By adopting a two-stage countercurrent leaching mode, the medicament consumption can be effectively reduced, and the leaching rates of Cu and Zn can be improved. The liquid-solid ratio of NH 4 Br solution to ash is controlled to be 3-6:1, and the treatment capacity of the subsequent leaching solution is reduced while the leaching rate of Cu and Zn is ensured. The pH is controlled to be 4.5-5.2, and volatilization of NH 4 Br solution is avoided while Cu and Zn leaching rates are ensured. S2, reducing and precipitating, namely adding a reducing agent I and pure water into the first-stage leaching solution, stirring and reacting, controlling the adding and reacting time to be 1-2 hours, controlling the reacting temperature to be 5-15 ℃, and the volume ratio of the pure water to the first-stage leaching solution to be 1-2:1; The purpose of the reduction precipitation is to convert Cu 2+, cuBr 43- and other copper-bromine complexes in the first-stage leaching solution into CuBr precipitates (reducing slag) so as to realize the separation of Cu and Zn. The reducing agent I and the reducing agent II are added step by step, so that the effects of improving the reduction precipitation efficiency and reducing the consumption of the reducing agent are achieved. Pure water is added into the first-stage leaching solution, the volume ratio of the pure water to the first-stage leaching solution is controlled to be 1-2:1, the Br concentration of the solution can be reduced, the stability of the coppe