Method for the treatment of iron-containing sludge

Patent metadata

Field	Value
Publication number	US-12054804-B2
Application number	US-201816755789-A
Country	US
Kind code	B2
Filing date	Dec 13, 2018
Priority date	Dec 22, 2017
Publication date	Aug 6, 2024
Grant date	Aug 6, 2024

Abstract

A method for the treatment of sludge containing iron, the method including a leaching step wherein the sludge containing iron is mixed with an acid and an oxidation agent so as to create an oxidized leachate, and a step of precipitation of iron wherein the oxidized leachate is mixed with a neutralizing agent so as to create a mixture composed of a solid part including precipitated iron and of a liquid part, the neutralizing agent including at least 30% in weight of dust recovered from a bag filter treatment of ironmaking, steelmaking, coke making or sintering gas.

First claim

What is claimed is:

1. A method for the treatment of sludge containing iron, the method comprising:
leaching the sludge containing iron by mixing the sludge containing iron with an acid and an oxidation agent so as to create an oxidized leachate; and
precipitating the iron by mixing the oxidized leachate with a neutralizing agent so as to create a mixture composed of a solid part including precipitated iron and a liquid part, the neutralizing agent including at least 30% in weight of dust recovered from a bag filter treatment of sintering gas.

2. The method as recited in claim 1 wherein the neutralizing agent includes less than 65% in weight of lime.

3. The method as recited in claim 1 further comprising, after the precipitation of the iron, separating the mixture so as to recover separately the solid part including the precipitated iron and the liquid part, the solid part further including carbon.

4. The method as recited in claim 3 wherein the solid part includes at least 8% in weight of iron, at least 15% in weight of carbon, less than 0.4% in weight of zinc and less than 0.1% in weight of lead.

5. The method as recited in claim 1 wherein the solid part includes at least 8% in weight of iron, at least 15% in weight of carbon, less than 0.4% in weight of zinc and less than 0.1% in weight of lead.

6. The method as recited in claim 1 wherein the dust includes less than 0.1% w of zinc, less than 1% w of lead, between 0.5% w and 2.5% w of silica SiO 2 , between 2 and 5% of potassium, between 2% w and 5% w of chloride, less than 2% w of sulphur, at least 8% w of iron, at least 10% w of carbon, at least 25% w of calcium oxide and between 1 and 3% w of magnesium oxide, a balance being oxygen and unavoidable impurities.

7. The method as recited in claim 4 wherein the dust includes less than 0.1% w of zinc, less than 1% w of lead, between 0.5% w and 2.5% w of silica SiO 2 , between 2 and 5% of potassium, between 2% w and 5% w of chloride, less than 2% w of sulphur, at least 8% w of iron, at least 10% w of carbon, at least 25% w of calcium oxide and between 1 and 3% w of magnesium oxide, a balance being oxygen and unavoidable impurities.

8. The method as recited in claim 5 wherein the dust includes less than 0.1% w of zinc, less than 1% w of lead, between 0.5% w and 2.5% w of silica SiO 2 , between 2 and 5% of potassium, between 2% w and 5% w of chloride, less than 2% w of sulphur, at least 8% w of iron, at least 10% w of carbon, at least 25% w of calcium oxide and between 1 and 3% w of magnesium oxide, a balance being oxygen and unavoidable impurities.

9. The method as recited in claim 1 wherein the sludge containing iron is blast furnace sludge.

10. The method as recited in claim 2 wherein the sludge containing iron is blast furnace sludge.

11. The method as recited in claim 3 wherein the sludge containing iron is blast furnace sludge.

12. The method as recited in claim 4 wherein the sludge containing iron is blast furnace sludge.

13. The method as recited in claim 5 wherein the sludge containing iron is blast furnace sludge.

14. The method as recited in claim 6 wherein the sludge containing iron is blast furnace sludge.

15. The method as recited in claim 7 wherein the sludge containing iron is blast furnace sludge.

16. The method as recited in claim 8 wherein the sludge containing iron is blast furnace sludge.

17. The method as recited in claim 1 wherein the oxidizing agent consists of chlorates and chlorate ions.

18. The method as recited in claim 1 wherein the neutralizing agent comprises a mixture comprising the dust recovered from the bag filter treatment of sintering gas and lime.

Assignees

• Arcelormittal

Inventors

• Kerzerho Gaelle
• Boucard Helene
• Iosif Ana-Maria

Classifications

• C22B13/045

  Recovery from waste materials · CPC title

• C22B7/02

  Working-up flue dust · CPC title

• C22B7/007 Primary

  by acid leaching · CPC title

• C22B19/00

  Obtaining zinc or zinc oxide · CPC title

• Y02P10/20

  Recycling · CPC title