Abstract
Nanostructured materials are widely used to improve the properties of consumer products such as tires, cosmetics, light weight equipment etc. Due to their complex composition these products are hardly recycled and thermal treatment is preferred. In this study we investigated the thermal stability and material balance of nanostructured metal oxides in flames and in an industrial waste incinerator. We studied the size distribution of nanostructured metal oxides (CeO2, TiO2, SiO2) in a flame reactor and in a heated reaction tube. In the premixed ethylene/air flame, nano-structured CeO2 partly evaporates forming a new particle mode. This is probably due to chemical reactions in the flame. In addition sintering of agglomerates takes place in the flame. In the electrically heated reaction tube however only sintering of the agglomerated nanomaterials is observed. Ceria has a low background in waste incinerators and is therefore a suitable tracer for investigating the fate of nanostructured materials. Low concentrations of Ceria were introduced by a two-phase nozzle into the post-combustion zone of a waste incinerator. By the incineration of coal dust in a burning chamber the Ceria nanoparticles are mainly found in the size range of the fly ash (1 – 10 µm) because of agglomeration. With gas as a fuel less agglomeration was observed and the Ceria nanoparticles were in the particle size range below 1 µm.
Highlights
The amount of consumer products containing engineered nanomaterials is constantly growing
The melting temperature of the bulk material is around 2000 °C and the density is 7.3 g/cm[3]
With increasing cold gas velocity and flame temperature a new particle mode around 10 nm starts to form. This experiment was executed with a few metal oxides (CeO2, TiO2, SiO2) and the same effect was observed
Summary
The amount of consumer products containing engineered nanomaterials is constantly growing As these products reach their end of life they often end up in the waste incineration. In the Institute for Technical Chemistry at the Karlsruhe Institute of Technology (KIT) this topic is analysed in fundamental investigations of NP behaviour in lab-scale flames (Lang et al 2015; Teuscher et al 2016), in technical investigations at a 3 MW combustion chamber at the KIT (Scherrmann et al 2016) and in large-scale investigations at an industrial hazardous waste incineration plant in the chemical industry. These can be the exhaust gas, the waste water or the solid residues. The melting temperature of the bulk material is around 2000 °C and the density is 7.3 g/cm[3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
