초록 ▼

A continuous process and apparatus for the repurification of ultrapure liquids. An oxidant solution comprising ultrapure sulfuric acid, peroxydisulfuric acid, and ultrapure water is continuously withdrawn from a process after use. The withdrawn oxidant is reprocessed continuously by contacting with

A continuous process and apparatus for the repurification of ultrapure liquids. An oxidant solution comprising ultrapure sulfuric acid, peroxydisulfuric acid, and ultrapure water is continuously withdrawn from a process after use. The withdrawn oxidant is reprocessed continuously by contacting with alumina to remove fluoride ions. Water is continuously separated or stripped from the oxidant solution by heating the solution and bubbling an inert gas therethrough causing the water to vaporize from the solution. The separated oxidant is continuously distilled and condensed to form a purified stream of sulfuric acid. The major portion of this stream is continuously returned to the process. The remaining minor portion is continuously cooled, subjected to analysis for purity, and diluted with ultrapure water. The diluted sulfuric acid is further cooled prior to electrochemical treatment in the anode compartment of an electrochemical cell. This converts at least a portion of the dilute sulfuric acid to peroxydisulfuric acid. The resulting solution is continuously returned to the process to be mixed with the major portion of the purified sulfuric acid. A system of apparatus to conduct the processes is provided which also includes means for continuously analyzing the minor portion for purity and trace elements.

대표청구항 ▼

A process for the regeneration and repurification of ultrapure oxidant solution comprising ultrapure sulfuric acid, ultrapure peroxydisulfuric acid, and ultrapure water which is used in a chemical process utilizing said ultrapure oxidant solution comprising: withdrawing at least a portion of said ox

A process for the regeneration and repurification of ultrapure oxidant solution comprising ultrapure sulfuric acid, ultrapure peroxydisulfuric acid, and ultrapure water which is used in a chemical process utilizing said ultrapure oxidant solution comprising: withdrawing at least a portion of said oxidant solution used in said chemical process; distilling said withdrawn oxidant solution to remove particles and dissolved impurities to form ultrapurified sulfuric acid; dividing said ultrapurified sulfuric acid into a major portion and a minor portion; returning said major portion of said ultrapurified sulfuric acid to said chemical process; diluting said remaining minor portion of said ultrapurified sulfuric acid with ultrapure water to produce a stream of diluted ultrapure sulfuric acid; introducing said diluted ultrapure sulfuric acid into the anode compartment of an electrochemical cell where at least a portion of said diluted ultrapure sulfuric acid is converted into ultrapure peroxydisulfuric acid; adding at least a portion of said resulting solution of ultrapure sulfuric acid, ultrapure peroxydisulfuric acid, and ultrapure water to said chemical process where it is admixed with said major portion of said ultrapure sulfuric acid to reform said ultrapure oxidant solution.