US 5,057,334 A · Process for recovery of cellulose

Abstract

The present invention is directed to a process for the production of an improved purified short fiber cellulose suitable for human consumption from agricultural by-product materials, such as legume hulls, preferably soybean hulls. The legume hulls are comminuted into a particulate feed which is admixed with water to form a slurry. The slurried particulate legume hulls are oxidized, hydrolyzed and extracted with a caustic oxidizing agent utilizing an initial pH of about 12 to effect solubilization of the greater portion of non-cellulose material in the feed. A solid cellulose containing material is thereafter removed from the slurry, for example, by filtration or centrifugation. The recovered solid mass is slurried in water and the resulting slurry if pH adjusted to about 7 by the addition of phosphoric acid. The resulting suspension is agitated and H.sub.2 O.sub.2 is added, and the mixture is heated to promote bleaching and breakdown of the non-cellulose components. The resulting mixture is subjected to a separation operation and a residue is recovered which consists primarily of microcrystalline alpha-cellulose fibers.

Claims8

Dependent claims

A process for the production of purified short fiber cellulose suitable for human consumption, from the hulls of edible legumes, comprising the steps of:

(a) forming a slurry of particulate legume hulls in water,
(b) adding caustic oxidizing agent to the slurry to raise the pH to about 12,
(c) maintaining a highly alkaline pH in said slurry for 61/2 to 23 hours during which the temperature of the slurry is maintained at 190.degree. F. to 210.degree. F. for at least 30 minutes, to oxidize, hydrolyze and extract the particulate legume hulls, thereby to solubilize the greater portion of the non-cellulose material present therein and form a pulp which consists predominantly of cellulose, in the slurry,
(d) separating the pulp from the slurry,
(e) redispersing the separated pulp in water to form a further slurry,
(f) adjusting the pH of the further slurry to be in the range of from about 6.5 to 7.5 by the addition of phosphoric acid,
(g) adding to the pH adjusted slurry resulting from (f) a bleaching effective amount of aqueous hydrogen peroxide solution, and mixing, and heating the resulting admixture to a below boiling temperature to promote breakdown of any non-cellulose material present and bleaching of the pulp, and
(h) separating from the resulting admixture a bleached pulp composition consisting predominantly of short fiber cellulose.

5 more elements

Dependencies are inferred from the claim text.

Process for recovery of cellulose

Life of this patent

Process for recovery of cellulose

Life of this patent

Abstract

Claims8