Reverse ion exchange process for lithium containing glass

Abstract

A method of reworking lithium containing ion exchanged glass-based articles is provided. The method includes a reverse ion exchange process that returns the glass-based article to approximately the composition of the glass from which the glass-based article was produced, before being subjected to ion exchange.

1 - 14 . (canceled) 
     
     
         15 . A method, comprising:
 reverse ion exchanging an ion exchanged glass-based article in a first reverse ion exchange medium; and   reverse ion exchanging the ion exchanged glass-based article in a second reverse ion exchange medium to produce a reverse ion exchanged glass-based article,   wherein the first reverse ion exchange medium comprises a sodium salt, and the second reverse ion exchange medium comprises a sodium salt and a lithium salt.   
     
     
         16 . The method of  claim 15 , wherein the second reverse ion exchange medium further comprises a non-ion exchangeable multivalent metal salt. 
     
     
         17 . The method of  claim 16 , wherein the non-ion exchangeable multivalent metal salt comprises at least one of a nitrate, sulfate, and a chloride. 
     
     
         18 . The method of  claim 16 , wherein the non-ion exchangeable multivalent metal salt comprises at least one of calcium nitrate, magnesium nitrate, and strontium nitrate. 
     
     
         19 . The method of  claim 16 , wherein the second reverse ion exchange medium comprises the non-ion exchangeable multivalent metal salt in an amount of greater than or equal to 5 wt %. 
     
     
         20 . The method of  claim 15 , wherein the sodium salt in the first reverse ion exchange medium is sodium nitrate. 
     
     
         21 . The method of  claim 15 , wherein the lithium salt in the second reverse ion exchange medium is lithium nitrate. 
     
     
         22 . The method of  claim 15 , wherein the sodium salt in the second reverse ion exchange medium is sodium nitrate. 
     
     
         23 . The method of  claim 15 , wherein the first reverse ion exchange medium is at a temperature of greater than or equal to 400° C. to less than or equal to 420° C. 
     
     
         24 . The method of  claim 15 , wherein the reverse ion exchange in the first reverse ion exchange medium extends for a period of greater than or equal to 5 minutes to less than or equal to 24 hours. 
     
     
         25 . The method of  claim 15 , wherein the reverse ion exchange in the first reverse ion exchange medium extends for a period less than half of the total ion exchange time in the first and second reverse ion exchange mediums. 
     
     
         26 . The method of  claim 15 , wherein the reverse ion exchange in the second ion exchange medium is at a temperature of greater than or equal to 380° C. to less than or equal to 400° C. 
     
     
         27 . The method of  claim 15 , wherein the reverse ion exchange in the second reverse ion exchange medium extends for a period greater than or equal to half of the total ion exchange time in the first and second reverse ion exchange mediums. 
     
     
         28 . The method of  claim 15 , wherein the first reverse ion exchange medium further comprises potassium. 
     
     
         29 . The method of  claim 15 , wherein the first reverse ion exchange medium further comprises KNO 3  in an amount greater than or equal to 6 wt %. 
     
     
         30 . The method of  claim 15 , wherein the first reverse ion exchange medium has a Na/Li ratio greater than a Na/Li ratio of the second reverse ion exchange medium. 
     
     
         31 . The method of  claim 15 , further comprising removing between 1 μm and 10 μm from the surface of the reverse ion exchanged glass-based article. 
     
     
         32 . The method of  claim 15 , further comprising re-ion exchanging the reverse ion exchanged glass-based article in a re-ion exchange medium to form a re-ion exchanged glass-based article. 
     
     
         33 . The method of  claim 15 , further comprising ion exchanging a glass-based article in an ion exchange medium to form the ion exchanged glass-based article. 
     
     
         34 . A reverse ion exchanged glass-based article produced by the method of  claim 15 .