Treatment method of wastewater containing ferricyanide complex and oxalate

Patent metadata

Field	Value
Publication number	US-2024270613-A1
Application number	US-202318557963-A
Country	US
Kind code	A1
Filing date	Mar 15, 2023
Priority date	May 31, 2022
Publication date	Aug 15, 2024
Grant date	—

Abstract

Provided is a treatment method of waste water containing ferricyanide complex and oxalate, comprising under the condition of weak acidity to weak alkalinity, firstly adding an appropriate amount of divalent manganese ions to make the divalent manganese ions combined with ferrocyanide ions and part of oxalate ions in wastewater to form a mixed slag mainly composed of manganese ferrocyanide to achieve the purpose of removing most of the cyanide and a small amount of organic substance; adding excess divalent manganese ions to the first filtrate to make the divalent manganese ions fully combined with the oxalate in the wastewater to achieve the purpose of removing organic substance, and then adding an appropriate amount of alkali to the second filtrate to form precipitation to achieve the purpose of recovering manganese; then adding an appropriate amount of ferrous salt to achieve the purpose of removing the remaining cyanide and organic substance.

First claim

1 . 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, and leaving the 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 the total cyanide in the wastewater; S2: adding divalent manganese salt B to the first filtrate, stirring for reaction, and adding flocculant A cationic polyacrylamide, and leaving the mixture to stand for settling, and performing solid-liquid separation to obtain a second filtrate and a filter residue, and performing a rinsing process on the filter residue to recover manganese oxalate; wherein the mass of the divalent manganese ions in the added divalent manganese salt B 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, and leaving the mixture to stand for settling, and performing solid-liquid separation to obtain a third filtrate and a filter residue, and performing a rinsing process on the filter residue to recover manganese resources; S4: adjusting the pH of the third filtrate to 5-8, then adding ferrous salt, stirring for reaction, and adding flocculant A cationic polyacrylamide, and leaving the 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; 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.

2 . The treatment method according to claim 1 , wherein in step S1, the content of total cyanide in the wastewater is 100-2000 mg/L, and the content of COD is 2000-10000 mg/L.

3 . The treatment method according to claim 1 , wherein the divalent manganese salt A and the divalent manganese salt B are independently at least one of manganese sulfate, manganese chloride or manganese nitrate.

4 . The treatment method according to claim 1 , wherein the flocculant A is a cationic polyacrylamide solution with a mass concentration of 0.5‰-1.5‰; the flocculant B is an anionic polyacrylamide solution with a mass concentration of 0.5‰-1.5‰.

5 . (canceled)

6 . (canceled)

7 . (canceled)

8 . (canceled)

9 . (canceled)

10 . The treatment method according to claim 1 , wherein in step S5, the content of total cyanide in the fifth filtrate is ≤0.5 mg/L, the content of COD is ≤500 mg/L, and the content of Mn 2+ ≤0.5 mg/L.

Assignees

• Guangdong Brunp Recycling Technology Co Ltd
• Hunan Brunp Recycling Tech Co Ltd

Inventors

• Yuan Qi
• Qiu Yali
• Liu Yongqi
• Liu Genghao
• Gong Qinxue
• Li Changdong

Classifications

• C02F1/5236

  using inorganic agents · CPC title

• C02F1/001 Primary

  Processes for the treatment of water whereby the filtration technique is of importance (C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00) · CPC title

• C02F2301/08

  Multistage treatments, e.g. repetition of the same process step under different conditions · CPC title

• C02F2101/34

  containing oxygen · CPC title

• C02F2101/203

  Iron or iron compound · CPC title