• Resources Recycling
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• v.16 no.1 s.75
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• pp.28-36
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• 2007

Nano-sized ITO powders with the average particle size below 50 nm were synthesized from complex acid solution dissolved the ITO target into hydrochloric acid by a spray pyrolysis process, and the influences of reaction factors as reaction temperature and concentration of raw material solution were investigated. As the reaction temperature increases from 800 to $1000^{\circ}C$, the average particle size of the ITO powder increases from 40 nm to 100 nm, the microstructure gradually becomes solid, individual particles independently appear with the shape of polygon, the particle size distribution becomes increasingly irregular, the XRD peak intensity gradually increases and the specific surface area decreases. As the concentration of the raw material solution increases from 50g/l to 400g/l, the average particle size of ITO powder gradually increases, yet the particle size distribution appears more irregular. When the concentration is at 50 g/l, the average particle size of ITO powder is below 30 nm and the particle size distribution appears comparatively uniform. Nevertheless, when the concentration reaches 400 g/l, which is close to e saturated concentration, the particle size distribution appears extremely irregular, and the particles with the size ranging from 20 nm to 100 nm coexist. Along with the concentration rise, the XRD peak intensity gradually increases, yet the specific surface area decreases.

• Resources Recycling
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• v.27 no.2
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• pp.24-31
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• 2018

In this study, waste ITO target is dissolved into hydrochloric acid to generate a complex indium-tin chloride solution. Nano sized ITO powder with an average particle size below 30 nm are generated from these raw material solutions by spray pyrolysis process. Also, in this study, thermodynamic equations for the formation of indium-tin oxide (ITO) are established. As the reaction temperature increased from $800^{\circ}C$ to $900^{\circ}C$, the proportion and size of the spherical droplet shape in which nano sized particles aggregated gradually decreased, and the surface structure gradually became densified. When the reaction temperature was $800^{\circ}C$, the average particle size of the generated powder was about 20 nm, and no significant sintering was observed. At a reaction temperature of $900^{\circ}C$, the split of the droplet was more severe than at $800^{\circ}C$, and the rate of maintenance of the initial atomized droplet shape decreased sharply. The average particle size of the powder formed was about 25 nm. The ITO particles were composed of single solid crystals, regardless of reaction temperature. XRD analysis showed that only the ITO phase was formed. Remarkably, the specific surface area decreased by about 30% as the reaction temperature increased from $800^{\circ}C$ to $900^{\circ}C$.