A physical recycling method of MLCC multi-metal complex waste

Abstract

The application discloses a physical recycling method for MLCC multi-metal complex waste, and belongs to the technical field of electronic waste resource utilization. MLCC multi-metal waste is crushed and dissolved in a solvent, and the slurry is maintained in stirring and synchronous magnetic separation, flushing and grinding to separate magnetic nickel. The slurry is further separated by centrifuge active reselection to separate silver and copper non-magnetic noble metals. Different materials are separately subjected to fractional reduced-pressure distillation, and the solvent is classified and recycled. The whole process is a pure physical process without adding acid, alkali and medicament. The problems of traditional process, such as metal particle agglomeration wrapping, low recovery rate of nickel, silver and copper noble metals, single metal and single solvent, are solved. The process has good synergy, high recovery rate of valuable metals, and the solvent can be classified and recycled, and is suitable for industrialized recycling of MLCC multi-metal complex waste.

Description

Technical Field

[0001] This invention belongs to the field of electronic waste resource recycling technology, specifically relating to a physical recycling method for MLCC multi-metal complex waste. Background Technology

[0002] The production and disposal of MLCC (Multilayer Ceramic Capacitor) chips generate a large amount of industrial waste. This type of waste has mixed components, containing precious metals such as nickel, copper, and silver, as well as various organic additives such as binders and solvents. Due to the frequent mixing and accumulation of factory waste, the composition is even more complex.

[0003] Existing MLCC recycling technologies are divided into chemical leaching and physical sorting. Chemical leaching requires the use of large amounts of acids and alkalis, generating a large amount of wastewater and easily introducing impurities. Most existing physical recycling schemes are only for ordinary MLCC waste, recovering only nickel and barium titanate, lacking efficient recovery of non-magnetic precious metals such as silver and copper, as well as valuable organic matter. Traditional processes generally involve first dissolving the material into a slurry, allowing it to settle, and then performing magnetic separation. This process easily leads to material agglomeration, with valuable metals being encapsulated, resulting in low metal recovery rates and low single-metal content. Solvent recovery mostly only recovers the single added solvent, failing to recover the solvent and valuable organic components in the raw material, leading to resource waste and high production costs.

[0004] Existing technologies disclose crushing, drying, magnetic separation, ultrasonic cleaning, and distillation unit operations, but their feasibility is low, and they have not yet been implemented. Furthermore, a complete set of synergistic processes for this type of multi-metal mixed MLCC waste is lacking. Therefore, developing a purely physical process that simultaneously recovers magnetic nickel, copper, and silver, as well as graded recovery of various organic additives, has practical application value. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art and provide a physical recycling method for complex multi-metal waste of MLCCs. The entire process is purely physical and does not use acid or alkali reagents. Synchronous stirring and magnetic separation scouring reduces metal encapsulation loss, centrifugation actively separates and recovers precious metals such as copper and silver, and vacuum fractional distillation recovers various organic additives. The solvent can be classified and recycled, resulting in a high recovery rate of valuable metals without introducing new impurities.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A physical recycling method for MLCC multimetallic complex waste, wherein the MLCC multimetallic complex waste contains two or more of magnetic nickel, silver and copper non-magnetic precious metals, as well as high-boiling solvents, binders, barium titanate, etc., comprising the following steps: (1) Crushing pretreatment: Crushing the complex multi-metal waste of MLCC to 10-200 mesh; adding it to the mixed solvent system, controlling the temperature at 25-100℃, the liquid-to-solid ratio at 3-6mL / s, the stirring speed at 1000-3000r / min, stirring for 1-6h, so that the binder and thickener in the waste are fully dissolved to form a uniform slurry; the mixed solvent is selected from one or more of water, ether, ester, hydrocarbon, ketone, and sulfoxide; (2) Synchronous stirring-magnetic separation-washing-grinding separation: The slurry is kept in a continuous stirring state, and magnetic separation, adsorption, washing and grinding are carried out simultaneously; magnetic nickel is adsorbed and retained by magnetic separation; the slurry that has been washed off enters the next process; (3) Active gravity separation of non-magnetic precious metals: After magnetic separation, the slurry is supplemented with solvent and sent to a centrifugal concentrator. Active gravity separation is carried out based on the density difference of the material to separate the non-magnetic precious metal solid phases of silver and copper. The remaining slurry enters the next process. (4) Staged vacuum distillation to recover multi-component solvents: The magnetic metal solid phase obtained by magnetic separation, the silver-copper precious metal solid phase obtained by gravity separation, and the slurry are subjected to vacuum distillation respectively; different distillation temperature ranges are controlled to recover solvents with different boiling points and other valuable components in turn; the various solvents recovered are returned to step (1) for recycling. (5) Product disposal: Magnetic metals and precious metals such as silver and copper after solvent removal by distillation are treated as metal products; compounds and residues are sold as resources or disposed of by qualified units according to their value and risk.

[0007] Furthermore, in step (2), the magnetic field strength of the magnetic separation is controlled to be 3000-9500 Gs.

[0008] Furthermore, in step (4), the vacuum degree of vacuum distillation is controlled to be -0.04~-0.095MPa, and the temperature is increased in stages. In the first stage, the low-boiling-point solvent is recovered at 45-65℃, and in the second stage, the high-boiling-point solvent and other valuable components are recovered at 70-160℃.

[0009] Furthermore, in step (3), the separation factor of the centrifugal concentrator is 40-200, preferably 80-200, and the slurry mass concentration is 14-25%.

[0010] Furthermore, the entire recycling process does not involve the addition of acidic or alkaline chemical reagents; it is a purely physical separation process. Beneficial effects

[0011] 1. This invention targets complex MLCC waste containing nickel, cobalt, silver, copper, and various organic additives. It employs a process of simultaneous stirring, magnetic separation, and scouring and grinding, keeping the material in a state of constant agitation to prevent valuable metal particles from agglomerating and clogging. It eliminates the need for ultrasonic equipment, simplifies the equipment, and improves the metal recovery rate. 2. Centrifugal active gravity separation is used to specifically recover non-magnetic precious metals such as silver and copper, which is different from ordinary static sedimentation solid-liquid separation and can achieve effective enrichment and recovery of precious metals. 3. By adopting segmented vacuum distillation, the added solvent, the solvent in the waste and other valuable organic components can be recovered separately and recycled, which greatly reduces the consumption of organic solvents; 4. The entire process is purely physical, without the addition of acids or alkalis, and will not introduce new impurities, resulting in high-quality metal products and low levels of waste. 5. The entire process is continuously matched, and magnetic metals, non-magnetic metals, valuable organic matter, and solvents are recovered simultaneously, resulting in high overall economic benefits. Detailed Implementation Example

[0012] Take 1000 grams of complex MLCC waste: (1): Pulverize to 120 mesh; use dimethyl sulfoxide-diethylene glycol monobutyl ether-water mixed solvent, liquid-solid ratio 4:1L / s, temperature 60℃, stirring speed 1500r / min, stir for 1h to fully dissolve organic matter to obtain slurry; (2): The slurry is continuously stirred, and the magnetic field strength is 8000Gs. Synchronous magnetic separation, scouring and grinding are performed to retain nickel magnetic metal. The slurry then enters the next process. (3): Add solvent, the slurry enters the centrifuge, the separation factor of the centrifugal concentrator is 100, and silver metal solid phase is enriched; (4): Vacuum distillation of magnetic metal nickel solid phase and silver metal solid phase respectively; vacuum degree -0.085MPa; first stage 60℃ to recover low boiling point solvent; second stage 115℃, 134℃ and 148℃ to recover different high boiling point solvents respectively; the solvent is prepared and reused in process (1). (5): Obtain nickel metal products and silver metal products; compliant disposal of compounds and residues.

[0013] Test results: Nickel recovery rate 99.6% (nickel content greater than 99.3%), silver recovery rate 91.5%; total recovery rate of terpineol (valuable component in waste) and added solvents 96%.

[0014] Using the same raw materials, the slurry is allowed to settle and then magnetically separated, ultrasonically cleaned, and without synchronous rinsing; simple sedimentation separation is performed, and atmospheric distillation is used to recover only the ethanol solvent.

[0015] Results: Nickel content was less than 97.3% (a prerequisite for ultrasonic cleaning); no silver was recovered; the total utilization rate of low-boiling-point solvents was less than 90%; and no high-boiling-point solvents and organic matter were recovered.

[0016] The comparison shows that the recovery rate and content of valuable metals, as well as the recovery efficiency of solvents and valuable organic matter, of the process in this application are significantly better than those of traditional processes, and it does not require energy-consuming drying and ultrasonic cleaning.

Claims

1. Claims A physical recycling method for complex multimetallic waste from MLCCs, characterized in that, The MLCC waste contains two or more of the following non-magnetic precious metals: magnetic nickel, silver, and copper, as well as high-boiling solvents, binders, barium titanate, etc., and includes the following steps: (1) Crushing pretreatment: Crush the complex MLCC multi-metal waste to 10-200 mesh; put it into a mixed solvent system, control the temperature at 25-100℃, the liquid-to-solid ratio at 3-6L / S, the stirring speed at 1000-3000r / min, and stir for 1-6h to fully dissolve the binder and thickener in the waste and form a uniform slurry; the mixed solvent is selected from one or more of water, ether, ester, hydrocarbon, ketone, and sulfoxide; (2) Synchronous stirring-magnetic separation-washing-grinding separation: The slurry is kept in a continuous stirring state, and magnetic separation, adsorption, washing and grinding are carried out simultaneously; magnetic nickel is adsorbed and retained by magnetic separation; The slurry that has been washed away and stripped away enters the next process; (3) Active gravity separation of non-magnetic precious metals: After magnetic separation, the slurry is supplemented with solvent and sent to a centrifugal concentrator. Active gravity separation is carried out based on the density difference of the material to separate the non-magnetic precious metal solid phases of silver and copper. The remaining slurry enters the next process. (4) Staged vacuum distillation to recover multi-component solvents: The magnetic metal solid phase obtained by magnetic separation, the silver-copper precious metal solid phase obtained by gravity separation, and the slurry are subjected to vacuum distillation respectively; different distillation temperature ranges are controlled to recover solvents with different boiling points and other valuable components in turn; the various solvents recovered are returned to step (1) for recycling. (5) Product disposal: Nickel, silver and copper precious metals after distillation to remove solvent are used as metal products; compounds and residues are sold as resources or disposed of by qualified units according to their value and risk.

2. The recycling method according to claim 1, characterized in that: In step (2), the magnetic field strength of the magnetic separation is controlled to be 3000-9500 Gs.

3. The recycling method according to claim 1, characterized in that: Step (4) The vacuum degree of vacuum distillation is controlled at -0.04~-0.095MPa. The temperature is increased in stages. In the first stage, the low boiling point solvent is recovered at 45-65℃. In the second stage, the high boiling point solvent and valuable components are recovered at 70-160℃.

4. The recycling method according to claim 1, characterized in that: Step (3) The separation factor of the centrifugal concentrator is 40-200, preferably 80-200, and the slurry mass concentration is 14-25%.

5. The recycling method according to claim 1, characterized in that, The entire recycling process does not involve the addition of acidic or alkaline chemical reagents; it is a purely physical separation process.