VITREOUS CARBON SPHERES AND PELLETS

Vitreous carbon in the form of microspheres or pellets has a number of applications, especially in the field of catalytic supports. 

A typical process for the production of vitreous-carbon spheres is represented schematicctlly in Fig. 6.9.1 The precursor is a partially polymerized polymer such as furfuryl alcohol, catalyzed with p-toiuene sulfonic acid and mixed with acetone to obtain the proper viscosity for atomization.l l A pore former is added which can be an organic material with a high boiling point or sub-micron solid particles such as carbon black. Atomization occurs in the thermal reactor shown schematically in Fig. 6.10.1 The curing time is very brief because of the small size of the particles ( 45jum). 

The microspheres are then heat-treated from 530to 1330°C. If required, they can be partially oxidized to create micro- and transitional-pores. 

Catalytic Support. Vitreous carbon spheres are being considered as catalyst supports for iron and other metals. The material may offer some important advantages over other forms of carbon, such as lower inorganic impurities (which may poison the catalyst) and a more uniform pore structure. The activation mechanism and the properties and characteristics of catalytic materials are reviewed in greater detail in Ch. 10, Sec. 4.0. 

Other Applications Other applications include foams, low density fillers for plastics and high-temperature thermal insulation. 

---