Highly activated carbon from caustic digestion of rice hull ash and method
AssigneeAgritec, Inc.
InventorDouglas K. Stephens
Life of this patent
Estimating the term…
Abstract
Disclosed are highly activated carbon particles derived from caustic digestion of rice hull ash obtained from thermal pyrolysis of rice hulls having an iodine number of at least 650 to 1000. The activated carbon pores are free of silicate residue from the caustic digestion. Also disclosed are methods of removing the silicate residue from the caustic silicate solution during digestion effective to substantially improve the activation of the carbon particles to commercial grade.
Claims10
In a method for producing activated carbon particles which are separated, by filtration, from a caustic silicate solution produced from caustic digestion of rice hull ash, the ash being obtained from thermal pyrolysis of rice hulls and contains activated carbon particles and pores which contain a silicate residue, the improvement comprising,
- (a) washing the filtered activated carbon particles with hot water at temperatures of about 140.degree. F. to about 160.degree. F.,
- (b) washing the resulting damp activated carbon particles from step (a) with an aqueous mineral acid solution effective to dissolve and remove the silicate residue from the pores of the activated carbon particles, and
- (c) drying the activated carbon particles from step (b).
Activated carbon particles having an iodine number of at least 650 and a particle size of not more than 25 microns derived from a caustic digestion of rice hull ash, the ash being obtained by thermal pyrolysis of rice hulls.
Activated carbon particles having an iodine number of at least 650 and a particle size of not more than 25 microns derived from a caustic digestion of rice hull ash, the ash being obtained from thermal pyrolysis of rice hulls, said activated carbon particles contain pores which are free of silicate residue.
Dependencies are inferred from the claim text.