Silicotitanate molded body, production method thereof, adsorbent for cesium and/or strontium comprising silicotitanate molded body, and decontamination method for radioactive waste solution by using adsorbent

Patent metadata

Field	Value
Publication number	US-11400432-B2
Application number	US-201816628154-A
Country	US
Kind code	B2
Filing date	Jul 3, 2018
Priority date	Jul 5, 2017
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

Provided are a silicotitanate molded body having high strength and reduced generation of fine powder, a production method thereof, an adsorbent comprising the silicotitanate molded body, and a decontamination method of radioactive cesium and/or radioactive strontium by using the adsorbent. The silicotitanate molded body comprises: crystalline silicotitanate particles that have a particle size distribution in which 90% or more, on volume basis, of the particles have a particle size within a range of 1 μm or more and 10 μm or less and that are represented by a general formula of A2Ti2O3(SiO4).nH2O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium.

First claim

The invention claimed is:

1. A silicotitanate molded body comprising:
crystalline silicotitanate particles that have a particle size distribution in which 90% or more, on volume basis, of the particles have a particle size within a range of 1 μm or more and 10 μm or less and that are represented by a general formula of A 2 Ti 2 O 3 (SiO 4 ).nH 2 O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and
an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium.

2. The silicotitanate molded body according to claim 1 , further comprising niobium.

3. The silicotitanate molded body according to claim 2 , wherein the silicotitanate molded body has a compressive strength at failure of 5.0 N or more.

4. The silicotitanate molded body according to claim 1 , wherein a content of the oxide of one or more elements selected from the group of aluminum, zirconium, iron, and cerium is 20 wt % or less.

5. The silicotitanate molded body according to claim 1 , wherein the molded body has a cylindrical shape having an average diameter within a range of 300 μm or more and 3,000 μm or less.

6. An adsorbent for cesium and/or strontium, comprising the silicotitanate molded body according to claim 1 .

7. A decontamination method of a radioactive waste solution, comprising bringing an adsorbent for cesium and/or strontium comprising the silicotitanate molded body according to claim 1 into contact with a waste solution containing radioactive cesium and/or radioactive strontium.

8. The decontamination method of a radioactive waste solution according to claim 7 , comprising bringing the radioactive waste solution into contact with the adsorbent in a column flow mode at a linear velocity LV of 2 m/h or more and 40 m/h or less and a space velocity SV of 10 h −1 or more and 300 h −1 or less.

9. A production method of the silicotitanate molded body according to claim 1 , comprising:
extruding a mixture containing crystalline silicotitanate that has a particle size distribution in which 90% or more, on volume basis, of particles have a particle size within a range of 1 μm or more and 10 μm or less and that is represented by a general formula of A 2 Ti 2 O 3 (SiO 4 ).nH 2 O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium to form a molded body; and subsequently
drying the molded body.

10. An adsorbent for cesium and/or strontium, comprising the silicotitanate molded body according to claim 2 .

11. An adsorbent for cesium and/or strontium, comprising the silicotitanate molded body according to claim 3 .

12. An adsorbent for cesium and/or strontium, comprising the silicotitanate molded body according to claim 4 .

13. An adsorbent for cesium and/or strontium, comprising the silicotitanate molded body according to claim 5 .

14. A decontamination method of a radioactive waste solution, comprising bringing an adsorbent for cesium and/or strontium comprising the silicotitanate molded body according to claim 2 into contact with a waste solution containing radioactive cesium and/or radioactive strontium.

15. A decontamination method of a radioactive waste solution, comprising bringing an adsorbent for cesium and/or strontium comprising the silicotitanate molded body according to claim 3 into contact with a waste solution containing radioactive cesium and/or radioactive strontium.

16. A decontamination method of a radioactive waste solution, comprising bringing an adsorbent for cesium and/or strontium comprising the silicotitanate molded body according to claim 4 into contact with a waste solution containing radioactive cesium and/or radioactive strontium.

17. A decontamination method of a radioactive waste solution, comprising bringing an adsorbent for cesium and/or strontium comprising the silicotitanate molded body according to claim 5 into contact with a waste solution containing radioactive cesium and/or radioactive strontium.

18. A production method of the silicotitanate molded body according to claim 2 , comprising:
extruding a mixture containing crystalline silicotitanate that has a particle size distribution in which 90% or more, on volume basis, of particles have a particle size within a range of 1 μm or more and 10 μm or less and that is represented by a general formula of A 2 Ti 2 O 3 (SiO 4 ).nH 2 O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium to form a molded body; and subsequently
drying the molded body.

19. A production method of the silicotitanate molded body according to claim 3 , comprising:
extruding a mixture containing crystalline silicotitanate that has a particle size distribution in which 90% or more, on volume basis, of particles have a particle size within a range of 1 μm or more and 10 μm or less and that is represented by a general formula of A 2 Ti 2 O 3 (SiO 4 ).nH 2 O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium to form a molded body; and subsequently
drying the molded body.

20. A production method of the silicotitanate molded body according to claim 4 , comprising:
extruding a mixture containing crystalline silicotitanate that has a particle size distribution in which 90% or more, on volume basis, of particles have a particle size within a range of 1 μm or more and 10 μm or less and that is represented by a general formula of A 2 Ti 2 O 3 (SiO 4 ).nH 2 O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium to form a molded body; and subsequently
drying the molded body.

21. A production method of the silicotitanate molded body according to claim 5 , comprising:
extruding a mixture containing crystalline silicotitanate that has a particle size distribution in which 90% or more, on volume basis, of particles have a particle size within a range of 1 μm or more and 10 μm or less and that is represented by a general formula of A 2 Ti 2 O 3 (SiO 4 ).nH 2 O wherein A represents one or two alkali metal elements selected from Na and K, and n represents a number of 0 to 2; and an oxide of one or more elements selected from the group consisting of aluminum, zirconium, iron, and cerium to form a molded body; and subsequently
drying the molded body.

Assignees

• Ebara Corp
• Nippon Chemical Ind

Inventors

• Sakuma Takashi
• Komatsu Makoto
• Izumi Takeshi
• Miyabe Shinsuke
• Sakamoto Takeshi
• Noguchi Eiji
• Sugihara Kaori

Classifications

• B01J20/08

  comprising aluminium oxide or hydroxide; comprising bauxite · CPC title

• C04B35/462

  based on titanates · CPC title

• C01B33/20

  Silicates (persilicates C01B15/14 {; containing aluminium C01B33/26}) · CPC title

• B01J20/28011

  Other properties, e.g. density, crush strength · CPC title

• B01J20/06

  comprising oxides or hydroxides of metals not provided for in group B01J20/04 · CPC title