Binder composition for soil and solidification treatment method for soil

Patent metadata

Field	Value
Publication number	US-2022355352-A1
Application number	US-202017755109-A
Country	US
Kind code	A1
Filing date	Oct 22, 2020
Priority date	Oct 22, 2019
Publication date	Nov 10, 2022
Grant date	—

Abstract

A binder composition for immobilizing a toxic-containing material. This composition has excellent strength developing properties at low temperature and is capable of solidifying soil to suppress the elution of toxic materials from the soil.

First claim

1 . A binder composition for immobilizing a toxic-containing material, comprising:
a calcium silicate-containing composition having hydration reactivity selected from the group consisting of cement, blast furnace slag fine powder, fly ash, and clinker ash; and a sulfate salt; wherein the calcium silicate-containing composition and the sulfate are selected so that the binder composition is capable of forming an immobilized sediment at 4° C. in about 7 days after being mixed with the toxic-containing material, thereby immobilizing the toxic-containing material.

2 . The binder composition of claim 1 , wherein the calcium silicate-containing composition comprises (CaO) 3 .SiO 2 (C 3 S), wherein the C 3 S is more than about 45% by weight in the binder composition; and
the sulfate salt is anhydrous or monohydrate form of FeSO 4 or anhydrous CaSO 4 .

3 . The binder composition of claim 2 , wherein the calcium silicate-containing composition further comprises (CaO) 2 .SiO 2 (C 2 S), and optionally at least one of (CaO) 3 .Al 2 O 3 (C 3 A) and (CaO) 4 .Al 2 O 3 .Fe 2 O 3 (C 4 AF).

4 . The binder composition of claim 2 , wherein the C 3 S ranges from about 45% to about 80% by weight in the composition, and the FeSO 4 or the anhydrous CaSO 4 ranges from about 4% to about 15% by weight in the composition.

5 . The binder composition of claim 2 , wherein the C 3 S ranges from about 55% to about 75% by weight in the composition, and the anhydrous CaSO 4 ranges from about 6% to about 12% by weight in the composition.

6 . The binder composition of claim 2 , wherein the C 3 S is over 60% by weight in the composition, and the anhydrous CaSO 4 is about 10% by weight in the composition.

7 . The binder composition of claim 2 , further comprising Ca(OH) 2 ranging from about 5% to about 12% by weight in the composition.

8 . The binder composition of claim 2 , wherein the C 3 S ranges from about 45% to about 75% by weight in the composition, and the FeSO 4 ranges from about 4% to about 15% by weight in the composition.

9 . The binder composition of claim 2 , further comprising a material selected from the group consisting of CaCO 3 , MgO, Mg(OH) 2 , Basanite, and Gypsum.

10 . The binder composition of claim 1 , which has a bulk specific gravity ranging from about 0.7 to about 1.7.

11 . The binder composition of claim 1 , which has a pH value ranging from about 9.0 to about 13.0.

12 . A mixture comprising the binder composition of claim 1 and a toxic-containing material.

13 . The mixture of claim 12 , wherein the binder composition and the toxic-containing material are in a ratio such that a sediment formed from the composition and the material under about 4° C. reaches a strength of about 100 kPa within seven days in an unconfined compression test.

14 . The mixture of claim 12 , wherein the binder composition ranges from about 7% to about 15% by weight in the mixture.

15 . The mixture of claim 12 , wherein the toxic-containing material is soil, which contains a toxic selected from the group consisting of lead, arsenic, fluorine, boron, mercury, selenium, hexavalent chromium, cadmium, and the like.

16 . A method of immobilizing a toxic-containing material, comprising
(a) mixing the binder composition of claim 1 with the toxic-containing material to form a mixture; and (b) allowing the mixture to cure and form an immobilized sediment.

17 . The method of claim 16 , wherein step (b) takes place at a temperature of at or below about 4° C.

18 . The method of claim 16 , wherein the binder composition and the toxic-containing material is mixed in a ratio such that the immobilized sediment reaches a strength of about 100 kPa at or below about 4° C. by the seventh day after step (a) in an unconfined compression test.

19 . The method of claim 16 , further comprising, during or prior to step (a), adjusting the amount of C 3 S in the binder composition to control the rate of the immobilized sediment developing a strength of about 100 kPa according to UC test during a curing period in step (b).

20 . The method of claim 16 , wherein moisture content of the immobilized sediment varies by less than 5% from the seventh day through the twenty-eighth day during a curing period in step (b).

21 . (canceled)

Assignees

• Univ Rutgers
• Taiheiyo Cement Corp

Inventors

• Nozaki Takahito
• Higo Yasuhide
• Miskewitz Robert
• Maher Ali

Classifications

• C04B7/21 Primary

  with calcium sulfate containing activators {(C04B7/1535 takes precedence)} · CPC title

• C04B22/149

  Iron-sulfates · CPC title

• C04B2111/00767

  for waste stabilisation purposes · CPC title

• B09C1/08 Primary

  chemically · CPC title

• C04B18/08

  Flue dust {, i.e. fly ash} · CPC title