Treatment device and treatment method for chlorine bypass dust

Patent metadata

Field	Value
Publication number	US-9695086-B2
Application number	US-201113806297-A
Country	US
Kind code	B2
Filing date	Jun 8, 2011
Priority date	Jun 22, 2010
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

In accordance with the present invention, there is provided a treat chlorine bypass dust while preventing increases in chemical cost and concentrations of heavy metals in clinker, and ensuring stability in quality of cement. In a chlorine bypass facility 1 extracting a part G of combustion gas, while cooling it, from a kiln exhaust gas passage, which runs from an inlet end of a cement kiln to a bottom cyclone, and recovering a high chlorine concentration chlorine bypass dust D 5 from the extracted gas G 1 , a slurry S containing chlorine bypass dust and SO2 gas or/and CO2 gas are contacted with each other to obtain solid content. The slurry containing chlorine bypass dust and an exhaust gas from the chlorine bypass facility or/and the exhaust gas from the cement kiln can be contacted with each other, and the solid content can be fed to a cement finishing process, which allows cement with low CaO and Ca(OH)2 contents and with stable property such as setting time to be produced.

First claim

The invention claimed is:

1. A method of treating chlorine bypass dust in a chlorine bypass facility, the method comprising extracting a part of combustion gas, while cooling it, from a kiln exhaust gas passage, which runs from an inlet end of a cement kiln to a bottom cyclone, and recovering a chlorine bypass dust including compounds of calcium from the extracted gas, obtaining solid content by contacting a slurry including the chlorine bypass dust and a calcium compound with SO 2 gas or/and CO 2 gas, the SO 2 gas being received from a bag filter disposed between the kiln exhaust gas passage and a dissolution tank including the slurry, the CO 2 gas being exhaust gas from the cement kiln, added to the slurry via a gas introduction device separate from the kiln exhaust passage such that the SO 2 or/and CO 2 gas being added to the slurry separate from the chlorine bypass dust, and determining time for reacting the slurry containing the chlorine bypass dust to the SO 2 gas or/and the CO 2 gas by at least one selected from the group consisting of: rate of decrease in the SO 2 gas or/and the CO 2 gas when obtaining the solid content; pH of the slurry after being reacted with the SO 2 gas or/and the CO 2 gas, and chemical analysis of a concentration of calcium compounds in the chlorine bypass dust.

2. The method of treating chlorine bypass dust as claimed in claim 1 , wherein said slurry containing chlorine bypass dust and an exhaust gas from the chlorine bypass facility or/and the exhaust gas from the cement kiln are contacted with each other.

3. The method of treating chlorine bypass dust as claimed in claim 1 , wherein said solid content is fed to a cement finishing process.

4. The method of treating chlorine bypass dust as claimed in claim 1 , wherein said solid content is obtained after controlling pH of said slurry containing the chlorine bypass dust after contacted with the SO 2 gas or/and the CO 2 gas.

5. The method of treating chlorine bypass dust as claimed in claim 4 , wherein said pH of the slurry after being contacted with the SO 2 gas or/and the CO 2 gas is between 7.0 and 10.5.

6. The method of treating chlorine bypass dust as claimed in claim 2 , wherein said solid content is fed to a cement finishing process.

7. The method of treating chlorine bypass dust as claimed in claim 2 , wherein said solid content is obtained after controlling pH of said slurry containing the chlorine bypass dust after contacted with the SO 2 gas or/and the CO 2 gas.

8. The method of treating chlorine bypass dust as claimed in claim 7 , wherein said pH of the slurry after being contacted with the SO 2 gas or/and the CO 2 gas is between 7.0 and 10.5.

9. The method of treating chlorine bypass dust as claimed in claim 3 , wherein said solid content is obtained after controlling pH of said slurry containing the chlorine bypass dust after being contacted with the SO 2 gas or/and the CO 2 gas.

10. The method of treating chlorine bypass dust as claimed in claim 9 , wherein said pH of the slurry after contacted with the SO 2 gas or/and the CO 2 gas is controlled 7.0 or more and 10.5 or less.

11. The method of treating chlorine bypass dust as claimed in claim 1 , wherein SO 2 gas and CO 2 gas are added to the slurry.

Assignees

• Terasaki Junichi
• Kondou Kenzaburou
• Taiheiyo Cement Corp

Inventors

• Terasaki Junichi
• Kondou Kenzaburou

Classifications

• C04B7/60 Primary

  Methods for eliminating alkali metals or compounds thereof {, e.g. from the raw materials or during the burning process; methods for eliminating other harmful components (avoiding environmental pollution C04B7/364)} · CPC title

• B01D53/62

  Carbon oxides · CPC title

• F27D17/00

  Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases · CPC title

• C04B7/436 Primary

  Special arrangements for treating part or all of the cement kiln dust · CPC title

• B01D53/86

  Catalytic processes · CPC title