Search

CN-120442941-B - Method for recovering valuable elements through reduction smelting of NdFeB waste and electronic waste

CN120442941BCN 120442941 BCN120442941 BCN 120442941BCN-120442941-B

Abstract

The invention provides a method for recovering valuable elements by combining neodymium iron boron waste with electronic waste through reduction smelting, which comprises the steps of preparing powdery neodymium iron boron waste and fine particle electronic waste, a slag forming agent and a solid reducing agent, reducing and smelting the mixture by using a top-blown smelting furnace, reducing oxides of copper and iron in the mixture into metallic copper and metallic iron by controlling the conditions of a reduction process, and converging the metallic copper and the metallic iron with rare noble metals such as gold, silver and the like in the electronic waste into copper-iron noble metal alloy, wherein rare earth oxides are not reduced and remain in a slag layer, copper-iron noble metal alloy particles have higher density than rare earth slag, quickly descend into a furnace bottom in the slag layer, and respectively discharging copper-iron noble metal alloy melt and rare earth slag from a metal port and the slag port after standing and layering.

Inventors

  • HE WENCHENG

Assignees

  • 国瑞科创稀土功能材料(赣州)有限公司

Dates

Publication Date
20260505
Application Date
20250517

Claims (7)

  1. 1. The method for recovering valuable elements by reduction smelting of neodymium iron boron waste and electronic waste is characterized by comprising the following steps: S1, disassembling, sorting, crushing and ball milling pretreatment are carried out on neodymium iron boron waste and electronic waste, the pretreated powdery neodymium iron boron waste and fine granular electronic waste are mixed with a slag former and a solid reducing agent for proportioning, and a feeding system is used for feeding the mixture into a top-blown smelting furnace from a charging port at the top of the furnace; S2, introducing reducing gas and process air into the smelting furnace by using a smelting spray gun, controlling the temperature in the smelting furnace to 1300-1600 ℃, enabling the mixed material to float from the top to the bottom in a highly dispersed floating state, controlling the reducing atmosphere in the process to enable the oxygen partial pressure of a smelting system in the furnace to be lower than 10 -20 atm, enabling the oxides of copper and iron to be reduced into metallic copper and metallic iron in the falling process of the material, enabling the metallic copper and the metallic iron to form copper-iron noble metal alloy with gold and silver in electronic waste, enabling rare earth oxide not to be reduced, and forming rare earth slag phase with a slag former; S3, stopping adding materials and reducing agents after the reduction process is finished, lifting the smelting spray gun out of a molten pool for heat preservation, enabling slag to stand still and layer, and discharging copper-iron noble metal alloy melt and rare earth slag from a metal port and a slag port respectively; the granularity of the NdFeB waste is 50 meshes and below, and the granularity of the electronic waste is 10 mm-50 mm; the reducing atmosphere is that the ratio of reducing gas to process air quantity is 1:10-1:15, and the residual oxygen concentration of flue gas is 1% -4%; the reduced smelting flue gas is discharged after passing through a flue gas secondary combustion system, a waste heat recovery system, a flue gas quenching system, an active carbon injection system, a dust removal system and a desulfurization system in sequence.
  2. 2. The method of claim 1, wherein the electronic waste is discarded electronic or electrical equipment and components thereof.
  3. 3. The method according to claim 1, wherein the slag former is at least one of SiO 2 and CaO, and has a particle size of 1mm to 10mm.
  4. 4. The method according to claim 3, wherein the mass fraction w (Fe) of iron in the mixture is 15% -30%, the mass fraction w (SiO 2 ) of silicon dioxide is 25% -40%, the mass fraction w (CaO) of calcium oxide is 15% -25%, and the speed of adding the mixture from a charging port at the top of the furnace is 2 t/h-6 t/h.
  5. 5. The method of claim 1, wherein the reducing gas and the solid reducing agent are used as fuel.
  6. 6. The method of claim 5, wherein the reducing gas is one or more of carbon monoxide, hydrogen, natural gas, shale gas.
  7. 7. The method of claim 5, wherein the solid reducing agent is at least one of coke and coal.

Description

Method for recovering valuable elements through reduction smelting of NdFeB waste and electronic waste Technical Field The invention relates to the technical field of recycling of neodymium iron boron and electronic waste, in particular to a method for recycling valuable elements by combining neodymium iron boron waste with electronic waste reduction smelting. Background Rare earth is an important resource, called industrial monosodium glutamate, wherein neodymium iron boron materials are widely applied to industries such as motors, national defense, aviation, wind power and the like due to excellent performance. However, due to the reasons of process and equipment life, a large amount of NdFeB waste materials are generated, and the NdFeB waste materials contain a large amount of rare earth and iron, so that the NdFeB waste materials have great potential utilization value. Along with the rapid development of science and technology, the updating and iteration of electronic products are accelerated, the waste electronic products are increased, the core components in the electronic waste are circuit boards, the waste circuit boards not only contain valuable metals such as copper, gold, silver and the like, but also contain harmful heavy metal elements, and the waste circuit boards are listed in the national hazardous waste directory (number 900-045-49), and if the waste circuit boards are not utilized, the valuable metals are wasted, and the environment is polluted. At present, most of the treatment modes of neodymium iron boron waste adopt a fire method and a wet method to separate rare earth and iron, but the method does not fully utilize the separated iron, and the single-furnace treatment has high energy consumption and can generate a large amount of wastewater. The existing fire processes mainly comprise a closed blast furnace smelting process, an Osmanthi furnace smelting process, a flash furnace smelting process, a Kaldo furnace smelting process, a side-blown furnace smelting process, a bottom-blown furnace smelting process and the like, and due to the limitations of the smelting processes, the problems of low recovery rate, long flow, high energy consumption, low raw material adaptability, serious secondary pollution and the like still exist in the comprehensive recovery of valuable metals from the electronic waste by adopting the processes. In view of the foregoing, there is a need for an improved method for recovering rare earth and valuable metals from NdFeB scrap and electronic scrap. Disclosure of Invention The invention aims to provide a method for recovering valuable elements by reducing and smelting neodymium iron boron waste in cooperation with electronic waste. In order to achieve the aim of the invention, the invention provides a method for recovering valuable elements by reducing and smelting neodymium iron boron waste and electronic waste, which comprises the following steps: S1, carrying out pretreatment such as disassembly, sorting, crushing, ball milling and the like on neodymium iron boron waste and electronic waste, mixing the pretreated powder neodymium iron boron waste and fine granular electronic waste with a slag former and a solid reducing agent, and adding the mixture into a top-blown smelting furnace from a charging hole at the top of the furnace by using a feeding system. S2, introducing reducing gas and process air into the smelting furnace by utilizing a smelting spray gun, controlling the temperature in the smelting furnace to be 1300-1600 ℃, enabling the mixed material to float from the top to the lower end in a highly dispersed floating state, controlling the reducing atmosphere in the process to enable the oxygen partial pressure of a smelting system in the furnace to be lower than 10 -20 atm, enabling the oxides of copper and iron to be reduced into metallic copper and metallic iron in the falling process of the material, forming copper-iron noble metal alloy with gold and silver in the electronic waste, enabling the rare earth oxide not to be reduced, and forming a rare earth slag phase with a slag former. When the high-temperature melt obtained by reduction in the smelting furnace falls to the bottom of the smelting furnace, the melt is rapidly involved into a molten pool under the strong stirring of the airflow at the outlet of a smelting spray gun, the melt is fully and uniformly mixed with a solid reducing agent in the molten pool, bubbles are generated in the reduced slag by controlling the solid reducing agent amount and the ratio of reducing gas to process air, the kinetic conditions of the reduction reaction are further enhanced, a small part of unreduced copper and iron oxides are further reduced into metallic copper and metallic iron, and noble metals such as gold, silver and the like in the slag are trapped to form copper-iron noble metal alloy. And S3, stopping adding materials and reducing agents after the reduction process is finished, lifting the smeltin