Title:
PRODUCTION OF HIGH-PURITY SULFURIC ACID
Document Type and Number:
Japanese Patent JP3198575
Kind Code:
B2
Abstract:
PURPOSE: To obtain a high-purity sulfuric acid with reduced metallic impurities by making SO3 gas absorb into a liquid consisting of ultrapure water and/or high-purity sulfuric acid in an absorption column packed with a material consisting of synthetic silica glass.
CONSTITUTION: A specified quantity/time of liquid SO3 is introduced via a liquid SO3 introduction tube 1 into a vaporizer 2 kept at 45°C where it is vaporized, and the residual SO3 is drawn via a purge tube 4. The resulting SO3 gas is introduced via a tube 3 into the bottom of an absorption column 5 packed with Raschig rings consisting of synthetic silica glass. Concentrated sulfuric acid ≥90wt.% in concentration is introduced via a circulating sulfuric acid conductor 7 into the top of the absorption column and ultrapure water via the corresponding conductor 7 into the column to absorb the SO3 gas. Then the concentrated sulfuric acid after SO3 gas absorption is drawn off the bottom of the column 5, and, as necessary, is brought into contact with air in a packing column-type sulfurous acid-removing column to eliminate the contained SO2 gas, and the resultant concentrated sulfuric acid is passed through a filter 11 filtering the produced sulfuric acid to reduce the metal content (such as of Na, K and Ca) to ≤1ppb, thus obtaining the objective high-purity sulfuric acid.
Inventors:
Kawabata Kei
Application Number:
JP333492A
Publication Date:
August 13, 2001
Filing Date:
January 10, 1992
Export Citation:
Assignee:
Mitsubishi Chemical Corporation
International Classes:
C01B17/74; C01B17/90; (IPC1-7): C01B17/74
Domestic Patent References:
| JP60180905A | ||||
| JP627608A | ||||
| JP62138311A | ||||
| JP62167207A |
Attorney, Agent or Firm:
Koji Hasegawa