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Aerosol-assisted extraction of silicon nanoparticles from wafer slicing waste for lithium ion batteries.

Jang HD, Kim H, Chang H, Kim J, Roh KM, Choi JH, Cho BG, Park E, Kim H, Luo J, Huang J - Sci Rep (2015)

Bottom Line: This results in a significant loss of valuable materials at about 40% of the mass of ingots.Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals.The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing.

View Article: PubMed Central - PubMed

Affiliation: 1] Rare Metals Research Center, Korea Institute of Geoscience &Mineral Resources, Deajeon. 305-350, Korea [2] Department of Nanomaterials Science and Engineering, University of Science &Technology, Deajeon. 305-350, Korea.

ABSTRACT
A large amount of silicon debris particles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing.

No MeSH data available.


Related in: MedlinePlus

Schematic drawings illustrating the ultrasonic aerosol assisted Si extraction process.
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f1: Schematic drawings illustrating the ultrasonic aerosol assisted Si extraction process.

Mentions: Figure 1 shows schematic illustration of the aerosol-assisted Si recovery process. First, dried sludge containing a mixture of Si and SiC was redispersed in water and subject to ultrasonic atomization to disperse the particles and nebulize water droplets at the same time. Since the SiC particles have much larger size, higher density and much higher hardness, they can effectively grind the Si debris during ultrasonication, resulting in smaller and lighter Si particles that can also better disperse in water. Therefore, when the nebulized droplets leave water surface, Si particles are more likely to be captured and depart from the solution. As the carrier gas (Ar) is introduced into the reservoir, the droplets fly through a pre-heated tube furnace. During the flight, capillary force generated from solvent evaporation rapidly assembles the Si nanoparticles into clusters of submicron diameters. The dried product is then collected in a filter under vacuum, and analyzed with scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The particle size distribution was determined by a particle size analyzer (PSA) and counting more than 200 particles from the SEM images of corresponding samples as well. As shown in Figures 2a-1 and 2a-3, particles in the dried sludge have diverse size distribution from 0.2 to 15 μm in diameter. Most of the larger particles are SiC while the smaller ones are composed of mainly Si with a minor portion of SiC. The XRD result shows that the sludge consists of mainly Si and SiC and a small amount of Fe impurity (Fig. 2a-2). The Fe impurities can be easily removed by acid treatment as indicated by the XRD pattern (Fig. 2b-2)9. The SEM images and the size distribution of the sludge after acid treatment show that the initial particle morphology and size did not change greatly compared to those of the as-dried sludge (Figs. 2b-1 and 2b-3). Figure 2c-1 shows SEM and TEM images of the Si nanoparticle clusters obtained after aerosol extraction. SEM and TEM observations (Fig. 2c-1) show that the as-recovered particles are uniformly sized agglomerates of nanosized particles, resulting from the self-assembly of small nanoparticles due to the capillary force which arises during the evaporation of the solvent in the sprayed droplets. It was found that 80 wt% of Si was recovered from the silicon sludge by the aerosol process. Corresponding XRD pattern indicates the recovered material was mainly composed of Si with much reduced content of SiC (Fig. 2c-2). The mass fraction of SiC in the recovered material was measured to be 3.8 wt%, according to a chemical measurement method4. The sample shown in Figure 2 was collected from a sludge suspension with starting solid concentration of 0.5 wt%. The particle size of the as-prepared Si agglomerates ranged from 0.1 to 1.5 μm and centered at around 0.4 μm (Fig. 2c-3). With higher initial solid concentration, larger agglomerates can be obtained without significantly increasing the amount of SiC in the final product (supplementary materials Figure S1). The SEM image, XRD pattern, and particle size distribution of the residue in the reservoir of ultrasonic atomizer are shown in Figure S2. It is exhibited that the residue was mainly composed of SiC particles ranged from 2 to 20 μm after Si particles were recovered from the Si sludge powder. It is considered that the existence of remaining Si particles in the residue was due to strong agglomeration between Si and SiC particles. These results demonstrate that ultrasonic aerosol spray-drying method is promising process for recovering Si nanoparticles from waste sludge.


Aerosol-assisted extraction of silicon nanoparticles from wafer slicing waste for lithium ion batteries.

Jang HD, Kim H, Chang H, Kim J, Roh KM, Choi JH, Cho BG, Park E, Kim H, Luo J, Huang J - Sci Rep (2015)

Schematic drawings illustrating the ultrasonic aerosol assisted Si extraction process.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4377548&req=5

f1: Schematic drawings illustrating the ultrasonic aerosol assisted Si extraction process.
Mentions: Figure 1 shows schematic illustration of the aerosol-assisted Si recovery process. First, dried sludge containing a mixture of Si and SiC was redispersed in water and subject to ultrasonic atomization to disperse the particles and nebulize water droplets at the same time. Since the SiC particles have much larger size, higher density and much higher hardness, they can effectively grind the Si debris during ultrasonication, resulting in smaller and lighter Si particles that can also better disperse in water. Therefore, when the nebulized droplets leave water surface, Si particles are more likely to be captured and depart from the solution. As the carrier gas (Ar) is introduced into the reservoir, the droplets fly through a pre-heated tube furnace. During the flight, capillary force generated from solvent evaporation rapidly assembles the Si nanoparticles into clusters of submicron diameters. The dried product is then collected in a filter under vacuum, and analyzed with scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The particle size distribution was determined by a particle size analyzer (PSA) and counting more than 200 particles from the SEM images of corresponding samples as well. As shown in Figures 2a-1 and 2a-3, particles in the dried sludge have diverse size distribution from 0.2 to 15 μm in diameter. Most of the larger particles are SiC while the smaller ones are composed of mainly Si with a minor portion of SiC. The XRD result shows that the sludge consists of mainly Si and SiC and a small amount of Fe impurity (Fig. 2a-2). The Fe impurities can be easily removed by acid treatment as indicated by the XRD pattern (Fig. 2b-2)9. The SEM images and the size distribution of the sludge after acid treatment show that the initial particle morphology and size did not change greatly compared to those of the as-dried sludge (Figs. 2b-1 and 2b-3). Figure 2c-1 shows SEM and TEM images of the Si nanoparticle clusters obtained after aerosol extraction. SEM and TEM observations (Fig. 2c-1) show that the as-recovered particles are uniformly sized agglomerates of nanosized particles, resulting from the self-assembly of small nanoparticles due to the capillary force which arises during the evaporation of the solvent in the sprayed droplets. It was found that 80 wt% of Si was recovered from the silicon sludge by the aerosol process. Corresponding XRD pattern indicates the recovered material was mainly composed of Si with much reduced content of SiC (Fig. 2c-2). The mass fraction of SiC in the recovered material was measured to be 3.8 wt%, according to a chemical measurement method4. The sample shown in Figure 2 was collected from a sludge suspension with starting solid concentration of 0.5 wt%. The particle size of the as-prepared Si agglomerates ranged from 0.1 to 1.5 μm and centered at around 0.4 μm (Fig. 2c-3). With higher initial solid concentration, larger agglomerates can be obtained without significantly increasing the amount of SiC in the final product (supplementary materials Figure S1). The SEM image, XRD pattern, and particle size distribution of the residue in the reservoir of ultrasonic atomizer are shown in Figure S2. It is exhibited that the residue was mainly composed of SiC particles ranged from 2 to 20 μm after Si particles were recovered from the Si sludge powder. It is considered that the existence of remaining Si particles in the residue was due to strong agglomeration between Si and SiC particles. These results demonstrate that ultrasonic aerosol spray-drying method is promising process for recovering Si nanoparticles from waste sludge.

Bottom Line: This results in a significant loss of valuable materials at about 40% of the mass of ingots.Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals.The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing.

View Article: PubMed Central - PubMed

Affiliation: 1] Rare Metals Research Center, Korea Institute of Geoscience &Mineral Resources, Deajeon. 305-350, Korea [2] Department of Nanomaterials Science and Engineering, University of Science &Technology, Deajeon. 305-350, Korea.

ABSTRACT
A large amount of silicon debris particles are generated during the slicing of silicon ingots into thin wafers for the fabrication of integrated-circuit chips and solar cells. This results in a significant loss of valuable materials at about 40% of the mass of ingots. In addition, a hazardous silicon sludge waste is produced containing largely debris of silicon, and silicon carbide, which is a common cutting material on the slicing saw. Efforts in material recovery from the sludge and recycling have been largely directed towards converting silicon or silicon carbide into other chemicals. Here, we report an aerosol-assisted method to extract silicon nanoparticles from such sludge wastes and their use in lithium ion battery applications. Using an ultrasonic spray-drying method, silicon nanoparticles can be directly recovered from the mixture with high efficiency and high purity for making lithium ion battery anode. The work here demonstrated a relatively low cost approach to turn wafer slicing wastes into much higher value-added materials for energy applications, which also helps to increase the sustainability of semiconductor material and device manufacturing.

No MeSH data available.


Related in: MedlinePlus