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1. (WO2017153298) METHOD FOR RECOVERING PHOSPHORIC ACID FROM A SPENT PHOSPHORIC ACID / ALKALI METAL PERMANGANATE SALT ETCHING SOLUTION

Pub. No.:    WO/2017/153298    International Application No.:    PCT/EP2017/055086
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Sat Mar 04 00:59:59 CET 2017
IPC: C01B 25/234
C25D 5/56
C23C 18/16
C23C 18/18
C23C 18/20
C23C 18/24
C23C 18/54
H05K 3/18
C23F 1/46
C23C 18/22
Applicants: ATOTECH DEUTSCHLAND GMBH
Inventors: BROUZES, Alexandre
LAURENT, Matthieu
Title: METHOD FOR RECOVERING PHOSPHORIC ACID FROM A SPENT PHOSPHORIC ACID / ALKALI METAL PERMANGANATE SALT ETCHING SOLUTION
Abstract:
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.