Method for synthesizing high-purity montmorillonite

Patent metadata

Field	Value
Publication number	US-10758564-B2
Application number	US-201816158390-A
Country	US
Kind code	B2
Filing date	Oct 12, 2018
Priority date	Oct 12, 2017
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A method for synthesizing high purity montmorillonite is disclosed. According to this synthesis method, bentonite is dissolved in aqua regia to produce a solution and then sodium hydroxide (NaOH) is added to the solution to produce a mixed solution. Then, the mixed solution is kept in a sealed state at a temperature of 90° C. inclusive to 100° C. exclusive to synthesize montmorillonite crystals.

First claim

What is claimed is:

1. A method for synthesizing montmorillonite, the method comprising:
dissolving bentonite in aqua regia to produce a first solution;
adding sodium hydroxide (NaOH) to the first solution to produce a mixed solution; and
maintaining the mixed solution at a temperature of 90° C. inclusive to 100° C. exclusive to synthesize montmorillonite crystals,
wherein adding the sodium hydroxide (NaOH) to the first solution includes adding to the first solution a sodium hydroxide aqueous solution having a concentration of 3 M to 7 M and
wherein the sodium hydroxide aqueous solution is added to the first solution so that pH of the mixed solution is in a range of 11 to 13.

2. The method of claim 1 , wherein the bentonite includes finely-pulverized particles made of natural bentonite, each particle having a size of 2 mm or smaller,
wherein the aqua regia includes a mixture of hydrochloric acid (HCl) and nitric acid (HNO 3 ) at a molar ratio of about 1:3.

3. The method of claim 1 , wherein maintaining the mixed solution includes maintaining the mixed solution in a sealed state for about 20 to 30 hours.

4. The method of claim 1 , wherein the synthesized montmorillonite crystals have a specific surface area of about 125 to 135 cm 2 /g.

Assignees

• Korea Inst Geoscience & Mineral Resources

Inventors

• Seo Sung Man
• Kang Il Mo
• Roh Ki Min
• Kim Dae Young
• Kim Jae Hwan

Classifications

• A61K33/06 Primary

  Aluminium, calcium or magnesium; Compounds thereof {, e.g. clay} · CPC title

• C01B33/26 Primary

  Aluminium-containing silicates {, i.e. silico-aluminates} · CPC title

• B01J2208/00017

  Controlling the temperature · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01P2006/12

  Surface area · CPC title