High temperature aerosol processing Overview

High temperature aerosol processing • • • Overview Example of Ti. O 2 Vapor phase generators Spray pyrolysis Spray generation Jung Hyeun Kim’s presentation

Aerosol Reactors • Vapor Phase Reactors - Titania, Fumed Silica, Nitrides, etc. - Hot Wall, Flame, Plasma, Laser Ablation, Laser Pyrolysis • Spray Pyrolysis - Ferrites, Single and Multicomponent oxides, metals and alloys - Spray Nozzles - single and two fluid, Acoustic Sprayers and Nebulizers

Problem Particles • Process Effluents - Power Plant Fly Ash, Smelter Emissions, Sintering Plants • Contaminants - Contamination in Pharmaceutical, Semiconductor Industries (Mr. Doug Kremer on Thursday) • Occupational Exposure

Process Players • Solid/gas reactors - Reactant Feeding • Size Classification - Powder Dispersion in Gases • Coatings on Surfaces - Condensation

PRODUCTS • Titania pigment, Carbon blacks, Fumed silica, Alumina etc. • Metals and alloys - Ni, Ag, Au, Pd electronics circuits • Multicomponent Oxides - Ferrites, Superconductors, Dielectrics • Nanoscale Materials

Vapor Phase Reactors • Precursor is in vapor phase • Chemical reaction to condensable species or condensation of vapor happens to make products (can have combination of both) • Chemically reactive environment can be: flame, plasma, thermal with resistive heating, thermal via laser etc… • Condensation induced by mixing, expansion (big pressure gradients!) or both

Titania Process Oxygen Agglomerates Flame Fuel Fabric Filter Molecular Clusters Thermophoresis Wall Deposits Ti. Cl 4 Product

Titania Process • • Nucleation - Particle Formation Coagulation and Aggregate Formation Thermophoresis and Wall Losses Solid/Gas Separation - Fabric Filter(Bag House Collectors)

Agglomeration and Aggregation

Spray Pyrolysis • Very common method for making particles • Here precursor starts as droplets or solid particles • Thermal, plasma, flame also used as reaction environment but reaction is in liquid or solid phase (tiny microreactors!) • Mr. JH Kim will discuss this…

Droplet Drying and Conversion • Drying and conversion rates affect morphology of the particles • Can have hollow particles or can shatter particles • Mr. Kim will talk about effect of solvent on chemistry of particles • How to make spray? Some examples…

Video Images of Drying Droplet Time: 0 sec Time: 71 sec Time: 95 sec Time: 117 sec Time: 145 sec Time: 188 sec

Condensation Aerosol Generator Gas Condenser Vaporizer Heater

Nebulizer Aerosol Impaction Target

Nebulizer/Condensation Generator Condenser Evaporator Nebulizer Aerosol