Hydrate of Rare Earth Metal Sulfate, Method for Producing Same, and Chemical Thermal Storage Material

Patent metadata

Field	Value
Publication number	US-2019002302-A1
Application number	US-201616060118-A
Country	US
Kind code	A1
Filing date	Dec 8, 2016
Priority date	Dec 10, 2015
Publication date	Jan 3, 2019
Grant date	—

Abstract

An object of the present invention is to provide an inexpensive and highly safe compound useful as a chemical heat storage material that ensures high reproducibility even in repeated reactions (having high repetition durability), and is capable of reversibly advancing heat storage and heat dissipation even in a relatively low temperature range. The present invention is a hydrate of a rare earth metal sulfate having characteristic peaks at specific diffraction angles (2θ) in an X-ray diffraction pattern, which is measured using a copper radioactive ray of λ=1.5418 Å passed through a monochromator.

First claim

1 . A hydrate of a rare earth metal sulfate having characteristic peaks at the following diffraction angles (2θ) in an X-ray diffraction pattern, which is measured using a copper radioactive ray of λ=1.5418 Å passed through a monochromator:
Diffraction angles (2θ) at
13.0 to 14.0°,
16.5 to 17.5°,
19.5 to 20.5°,
24.5 to 25.5°, and
29.0 to 30.0°.

2 . The hydrate of a rare earth metal sulfate according to claim 1 , wherein the rare earth metal is at least one member selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, and yttrium.

3 . The hydrate of a rare earth metal sulfate according to claim 1 , represented by general formula (1):
M 2 (SO 4 ) 3 .n H 2 O  (1)
(in formula (1), M is at least one rare earth metal selected from the group consisting of La, Ce, Pr, Nd, and Y; n is greater than 0, and not more than 9).

4 . The hydrate of a rare earth metal sulfate according to claim 1 , wherein the hydrate of a rare earth metal sulfate is a monohydrate of a rare earth metal sulfate.

5 . A hydrate of a rare earth metal sulfate, represented by general formula (2):
M 2 (SO 4 ) 3 .1H 2 O  (2)
(in formula (2), M is at least one rare earth metal selected from the group consisting of La, Ce, Pr, Nd, and Y).

6 . A chemical heat storage material comprising the hydrate of a rare earth metal sulfate according to claim 1 , and further comprising a rare earth metal sulfate having characteristic peaks at the following diffraction angles (2θ) in an X-ray diffraction pattern, which is measured using a copper radioactive ray of λ=1.5418 Å passed through a monochromator:
Diffraction angles (2θ) at
13.0 to 14.0°,
16.5 to 17.5°,
19.5 to 20.5°,
24.5 to 25.5°, and
29.0 to 30.0°.

7 . A method for producing a hydrate of a rare earth metal sulfate having characteristic peaks at the following diffraction angles (2θ) in an X-ray diffraction pattern, which is measured using a copper radioactive ray of λ=1.5418 Å passed through a monochromator, the method comprising:
step (1) of heating a rare earth metal sulfate, or a hydrate of a rare earth metal sulfate that does not have the peaks, to 200° C. or more; and
step (2) of lowering the temperature of the rare earth metal sulfate obtained in step (1) in the presence of water vapor:
Diffraction angles (2θ) at
13.0 to 14.0°,
16.5 to 17.5°,
19.5 to 20.5°,
24.5 to 25.5°, and
29.0 to 30.0°.

8 . A method for producing a monohydrate of a rare earth metal sulfate, comprising:
step (1) of heating a rare earth metal sulfate, or a hydrate of a rare earth metal sulfate that does not have characteristic peaks at the diffraction angles (2θ) specified in claim 7 in an X-ray diffraction pattern, which is measured using a copper radioactive ray of λ=1.5418 Å passed through a monochromator, to 200° C.; and step (2) of lowering the temperature of the rare earth metal sulfate obtained in step (1) in the presence of water vapor.

9 . The method according to claim 7 , wherein the rare earth metal is at least one member selected from the group consisting of lanthanum, cerium, praseodymium, neodymium, and yttrium.

Assignees

• Univ Kyoto

Inventors

• Hatada Naoyuki
• Uda Tetsuya

Classifications

• C01F17/282 Primary

  Sulfates · CPC title

• C09K5/16 Primary

  Materials undergoing chemical reactions when used · CPC title

• C01P2002/88

  by thermal analysis data, e.g. TGA, DTA, DSC · CPC title

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title

• F28D20/003

  using thermochemical reactions · CPC title