http://rdf.ncbi.nlm.nih.gov/pubchem/patent/GB-475937-A
Outgoing Links
| Predicate | Object |
|---|---|
| assignee | http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_3a8d91abf7d60ad24b44327a9065a261 http://rdf.ncbi.nlm.nih.gov/pubchem/patentassignee/MD5_73ee0bacab5a7576a6a3244747f6ea99 |
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C01D1-32 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C01D1-32 |
| filingDate | 1936-05-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 1937-11-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | GB-475937-A |
| titleOfInvention | Process for the purification of solutions of alkali metal hydroxides |
| abstract | Silicon compounds are removed from aqueous solutions of alkali metal hydroxides containing up to 45--50 per cent alkali metal hydroxide, by digesting the solution with a mixture of two or more reagents at least one reagent being selected from each of the following groups: (a) the group consisting of the hydrated oxides, hydroxides and salts of trivalent iron, including the salts of acids derived from ferric oxide, e.g. sodium ferrite; (b) the group consisting of the oxide, hydroxide, and salts of calcium, the reagents being added in either order or simultaneously and in sufficient quantity to precipitate a substantial proportion of the silica, the quantity of iron compound (reckoned as Fe2O3) being about 1--3 mols. or more for each mol. of silica which it is desired to remove. Suitable iron salts are ferric chloride or sulphate. The trivalent iron compound may be formed in situ by the oxidation of a divalent iron compound. The calcium compound may be calcium hydroxide or carbonate and may be initially present in the alkali hydroxide solution as a slurry obtained in a previous lime causticizing process. Calcium sulphate, chloride, nitrate or nitrite are also suitable. The digestion is preferably conducted at elevated temperature, e.g. 100 DEG C., and the solution treated is preferably relatively dilute, e.g. a ten per cent solution. Aluminium and manganese compounds are also removed by the treatment to some extent, the removal of aluminium depending on the presence of silica. Specification 393,962 is referred to. |
| priorityDate | 1936-05-26-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 41.