http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-516515-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_23ad52b925a88b0bd88a04c658e1e658 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/D21C1-02 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/D21C3-26 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/D21C1-02 http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/D21C3-26 |
| filingDate | 1938-03-29-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1940-01-04-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-516515-A |
| titleOfInvention | Process for the extraction of cellulose from lignified fibrous material |
| abstract | 516,515. Refining cellulosic materials. KERR, W. T. March 29, 1938, No. 9586. [Class 2 (ii)] Cellulose fibres suitable for producing paper pulp are obtained from lignified material in divided state, by freeing the material from dust and other adherent matter, subjecting it to the action of a weak solution of an alkali hydroxide or carbonate at a temperature not above its boiling point at atmospheric pressure, then subjecting it while in movement to the action of a weak neutral or alkaline aqueous solution containing chlorine, the solution being maintained neutral or alkaline throughout the treatment, then subjecting it to a further treatment with a weak solution of an alkali hydroxide or carbonate at a temperature not above its boiling point, and then separating remaining undissolved impurities from the fibres. Sisal waste, jute waste, hemp, linseed flax straw, cotton linters, wood, e.g., black wattle, and eucalyptus, may be used as starting material. Wood is preferably used in the state of wood wool. Adherent matter and dust may be removed mechanically or by retting. The material may be packed into a metal cage which is immersed in a tank containing hot dilute alkali. The cage may be moved about in the alkali solution so as to ensure a thorough treatment of the fibrous material. The material is washed and then introduced into a long trough containing a warm neutral or alkaline solution of chlorine. It is continuously moved round the trough by means of a paddle-wheel. The solution is circulated and constantly replenished with fresh chlorine water. The solution is kept neutral or alkaline, e.g., by periodic additions of milk of lime. The solution is preferably maintained at a concentration of 1 per cent. available chlorine. The material is washed and then treated with a hot weak solution of caustic soda to remove lignin chloride and remaining chlorine. It is again washed, preferably with a powerful jet of water. If desired the chemical treatments and intermediate washings may be carried out as a continuous process by passing the material and the treating liquids along zig-zag channels of considerable length. At the end of each treatment the material is passed to a separator from which it is washed into a washing channel. After the final alkali treatment extraneous matter such as epidermal tissue, and thickened ends of leaf, is removed by a refiner screen. A preliminary separation may be effected by floating an oil such as cotton-seed oil on the surface of the treating liquid. The epidermal tissue collects in the oil layer and is removed by skimming. The effluents from the three stages may be mixed together to produce precipitation of dissolved substances and to produce an effluent which may be discharged without further treatment. |
| priorityDate | 1938-03-29-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 36.