Importance

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Abstract

The electronics industry demands that hydrogen peroxide for use therein be purified to very low levels of impurities, currently at the level of a few ppb for some impurities, or even lower. However, existing methods are either inherently unsafe because they bring concentrated hydrogen peroxide into contact with a concentrate of transition metal decomposition agents for peroxide and a purification resin which acts as a source of carbon, or are unable to attain the desired impurity level. The instant purification process first makes a concentrated suspension of stannic oxide particles in an aqueous medium, which can include aqueous hydrogen peroxide, by subjecting the mixture to high shear mixing, introducing an effective amount of the dispersion into the peroxide solution and filtering the mixture so as to remove the stannic oxide particles that now are loaded with ionic impurities, and particularly with transition metal ions. Purification to very low impurity levels can accordingly be made with improved safety.

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First Claim