Treatment method of wastewater containing ferricyanide complex and oxalate

A treatment method of wastewater containing ferricyanide complex and oxalate, comprising the following steps:

• S1:
• adjusting the pH of the wastewater to 5-9, then adding divalent manganese salt A to the wastewater, stirring for reaction, and adding flocculant A cationic polyacrylamide to obtain a first mixture, and leaving the first mixture to stand for settling, and performing solid-liquid separation to obtain a first filtrate and a manganese (II) hexacyanoferrate (II)-based mixed residue;
• wherein the wastewater contains ferricyanide complex and oxalate, and the mass of the divalent manganese ions in the added divalent manganese salt A is 5-30 times of the mass of total cyanide in the wastewater;
• S2:
• adding divalent manganese salt B to the first filtrate, stirring for reaction, and adding flocculant A cationic polyacrylamide to obtain a second mixture, and leaving the second mixture to stand for settling, and performing solid-liquid separation to obtain a second filtrate and a first filter residue, and performing a rinsing process on the first filter residue to recover manganese oxalate;
• wherein the mass of the divalent manganese ions in the added divalent manganese salt B per liter of the wastewater is 1.4-7 times of COD in the wastewater;
• S3:
• adding alkali to the second filtrate to adjust the pH of the second filtrate to 11-13, stirring for reaction, and adding flocculant B anionic polyacrylamide to obtain a third mixture, and leaving the third mixture to stand for settling, and performing solid-liquid separation to obtain a third filtrate and a second filter residue, and performing a rinsing process on the second filter residue to recover manganese residue;
• S4:
• adjusting the pH of the third filtrate to 5-8, then adding ferrous salt, stirring for reaction, and adding flocculant A cationic polyacrylamide to obtain a fourth mixture, and leaving the fourth mixture to stand for settling, and performing solid-liquid separation to obtain a fourth filtrate;
• wherein the addition amount of the ferrous salt is 5-30 g/L of the third filtrate;
• and,
• S5:
• adding alkali to the fourth filtrate to adjust the pH of the fourth filtrate to 11-13, stirring for reaction, and adding flocculant B anionic polyacrylamide, and performing solid-liquid separation to obtain a fifth filtrate.