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|1. (WO2017153298) METHOD FOR RECOVERING PHOSPHORIC ACID FROM A SPENT PHOSPHORIC ACID / ALKALI METAL PERMANGANATE SALT ETCHING SOLUTION|
|Applicants:||ATOTECH DEUTSCHLAND GMBH
|Title:||METHOD FOR RECOVERING PHOSPHORIC ACID FROM A SPENT PHOSPHORIC ACID / ALKALI METAL PERMANGANATE SALT ETCHING SOLUTION|
This invention pertains to a method for recovering phosphoric acid from a spent phosphoric acid / alkali metal permanganate salt etching solution containing at least one manganese oxide, characterized in that said process comprises the following successive steps: (a) heating the etching solution to a temperature between 90°C and 200°C so as to coalesce said at least one manganese oxide, (b) cooling down the resulting suspension, (c) centrifuging the cooled suspension so as to separate a liquid phase from a solid phase, and (d) recovering said liquid phase which contains phosphoric acid. It also pertains to a process for metallizing a non-conductive substrate, comprising an oxidation step with an etching solution, in which said etching solution is treated according to the above method.