Sludge composite conditioner based on iron-containing sludge pyrolysis residue as well as preparation method and use thereof

Patent metadata

Field	Value
Publication number	US-11858836-B2
Application number	US-201916446037-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Sep 18, 2017
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

The present disclosure discloses a sludge composite conditioner based on iron-containing sludge pyrolysis residue as well as a preparation method and use thereof. The sludge composite conditioner comprises iron-containing sludge pyrolysis residue and an oxidant used in combination with the iron-containing sludge pyrolysis residue, in which the iron-containing sludge pyrolysis residue is pyrolysis residue obtained by dewatering iron-containing sludge to obtain an iron-containing sludge cake and then pyrolyzing the iron-containing sludge cake, the iron-containing sludge being obtained from an advanced oxidation technology involving an iron-containing reagent. In the present disclosure, through improvements of the subsequent overall treatment process, the reuse mode and specific reaction condition parameters of the respective subsequent treatment process steps of the iron-containing sludge cake, the problem of sludge cake treatment and disposal at the end of the existing sludge treatment and disposal technology can be effectively solved compared with the prior art, and then the iron-containing sludge cake is utilized to form a composite conditioner for deep dewatering of sludge, which is recycled as a sludge conditioner for sludge treatment, thereby realizing the full utilization of resources.

First claim

What is claimed is:

1. A method, comprising:
dewatering an iron-containing sludge, that includes organic matter, to obtain an iron-containing sludge cake;
performing a pyrolysis treatment by pyrolyzing the iron-containing sludge cake, under an atmosphere of a protective gas at 600 to 1000° C. for 30 to 90 minutes, and the protective gas comprises at least one of nitrogen gas and argon gas, to obtain an iron-containing sludge pyrolysis residue that includes zero-valent iron, divalent iron compounds, trivalent iron compounds, and biochar;
adjusting a pH of a first sludge to be 1 to 6.5 to obtain a first treated sludge;
adding the iron-containing sludge pyrolysis residue to the first treated sludge, and stirring for 2 to 8 minutes to obtain a second treated sludge; and
adding a first oxidant to the second treated sludge, and stirring for 15 to 50 minutes, to obtain a conditioned sludge.

2. The method according to claim 1 , wherein the first sludge has a moisture content of 90 to 99%;
the pH is adjusted by adding an acid to the first sludge; and
the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, citric acid, and combinations thereof.

3. The method according to claim 1 , wherein the iron-containing sludge pyrolysis residue is added at an amount of 20 to 80% of a dry mass of the first sludge; and
the first oxidant is added at an amount of 3 to 10% of the dry mass of the first sludge.

4. The method according to claim 1 , wherein the iron-containing sludge is obtained by treating a sewage or a second sludge with an iron-containing reagent and a second oxidant.

5. The method according to claim 1 , wherein the iron-containing sludge is obtained by treating a sewage or a second sludge with a Fenton reagent or a reagent containing persulfate and ferrous salt.

6. The method according to claim 1 , wherein, before pyrolysis, the iron-containing sludge cake has a moisture content of 0 to 60% and an iron content of 8% to 30% relative to a dry mass of the iron-containing sludge cake.

7. The method according to claim 1 , wherein the first oxidant is selected from the group consisting of peroxide, persulfide, ozone, and a combination thereof, and a mass ratio of the iron-containing sludge pyrolysis residue to the first oxidant is 20 to 80:3 to 10.

8. The method according to claim 1 , wherein the protective gas is provided at a flow rate of 0.1 to 0.3 L/min.

Assignees

• Univ Huazhong Science Tech

Inventors

• Yang Jiakuan
• Tao Shuangyi
• Liang Sha
• Xiao Keke
• Yu Wenbo
• Qiu Jingjing
• Gan Quan
• Guan Ruonan
• Hou Huijie
• Liu Bingchuan
• Hu Jingping

Classifications

• C02F11/143 Primary

  using inorganic substances (C02F11/148 takes precedence) · CPC title

• C02F11/06

  by oxidation (incinerators for burning waste liquors, e.g. sulfite liquor from paper-making plant F23G7/04) · CPC title

• C02F11/10 Primary

  by pyrolysis · CPC title

• C02F2209/02

  Temperature · CPC title

• C02F2209/38

  Gas flow rate · CPC title