US2017088971A1PendingUtilityA1

Treatment of Etch Baths

41
Assignee: MACDERMID ACUMEN INCPriority: Sep 30, 2015Filed: Sep 30, 2015Published: Mar 30, 2017
Est. expirySep 30, 2035(~9.2 yrs left)· nominal 20-yr term from priority
Inventors:Roderick D. HerdmanTrevor PearsonRoshan V. Chapaneri
C23C 18/24C25D 5/56C25B 15/08C25D 21/18C09K 13/04
41
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Claims

Abstract

A method of maintaining a concentration of sulfuric acid in an electrolyte comprising manganese(III) ions in a solution of sulfuric acid. The method includes the steps of a) removing a portion of the electrolyte from the electrolytic cell to an annex tank; b) treating the removed portion of the electrolyte in the annex tank to remove moisture from the portion of the electrolyte; and c) returning the treated portion of the electrolyte to the electrolytic cell. The removed portion of the electrolyte is treated by passing a dry gas over the surface of the electrolyte in the annex tank to absorb moisture from the electrolyte and restore the concentration of sulfuric acid in the electrolyte.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A method of maintaining a concentration of sulfuric acid in an electrolyte comprising manganese(III) ions in a solution of sulfuric acid, the method comprising the steps of:
 a) removing a portion of the electrolyte from the electrolytic cell to an annex tank;   b) treating the removed portion of the electrolyte in the annex tank to remove moisture from the portion of the electrolyte; and   c) returning the treated portion of the electrolyte to the electrolytic cell;   wherein moisture in the treated portion of the electrolyte is removed or reduced.   
     
     
         2 . The method according to  claim 1 , wherein the annex tank is enclosed. 
     
     
         3 . The method according to  claim 1 , wherein the removed portion of the electrolyte is treated by passing a dry gas over the surface of the electrolyte in the annex tank. 
     
     
         4 . The method according to  claim 3 , wherein the dry gas is fed over the surface through a dry gas inlet. 
     
     
         5 . The method according to  claim 3 , wherein the annex tank further comprises a gas outlet, whereby, as the dry pass passes over the surface of the electrolyte and absorbs moisture, the moisture-filled gas can be removed from the annex tank. 
     
     
         6 . The method according to  claim 5 , wherein the dry gas is dry air. 
     
     
         7 . The method according to  claim 3 , wherein the temperature of the dry gas is between about 15 and about 30° C. 
     
     
         8 . The method according to  claim 3 , wherein the dry gas has a humidity at a point where it enters the enclosed annex tank of less than about 15%. 
     
     
         9 . The method according to  claim 8 , wherein the dry gas has a humidity at a point where it enters the enclosed annex tank of less than about 10%. 
     
     
         10 . The method according to  claim 1 , wherein step b) is performed on a continuous basis. 
     
     
         11 . The method according to  claim 1 , wherein step b) is performed on a batch basis. 
     
     
         12 . The method according to  claim 1 , wherein the electrolyte comprising manganese(III) ions is prepared by oxidizing an electrolyte comprising a solution of manganese(II) ions in at least one acid in an electrolytic cell wherein the electrolytic cell comprises an anode and a cathode; applying a current between the anode and the cathode; and oxidizing the electrolyte to form manganese(III) ions. 
     
     
         13 . The method according to  claim 1 , further comprising the step of monitoring the concentration of the at least one acid in the electrolyte prior to step a). 
     
     
         14 . The method according to  claim 1 , wherein step b) is performed for a period of time to remove moisture from the electrolyte and restore the concentration of sulfuric acid in the electrolyte. 
     
     
         15 . The method according to  claim 14 , wherein the period of time is in the range of about 1 to about 30 minutes. 
     
     
         16 . The method according to  claim 14 , wherein the concentration of sulfuric acid is restored to a concentration of at least about 8 molar. 
     
     
         17 . The method according to  claim 16 , wherein the concentration of sulfuric acid is restored to a concentration of between about 12 and about 13 molar. 
     
     
         18 . The method according to  claim 9 , wherein the dry gas is passed through a desiccant chamber prior to entering the enclosed annex tank.

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