Method of detoxifying asbestos contained in waste slate and detoxified asbestos obtained through the same

Patent metadata

Field	Value
Publication number	US-9446273-B2
Application number	US-201414309706-A
Country	US
Kind code	B2
Filing date	Jun 19, 2014
Priority date	Jun 25, 2013
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

Disclosed is a method of detoxifying asbestos of waste slate. The method includes concentrating the asbestos by introducing hydrochloric acid aqueous solution into waste slate powder to dissolve and remove a limestone component contained in the waste slate; and mixing the concentrated asbestos with oxalic acid and performing a low-temperature heat treatment. The waste slate is crushed and pulverized and powder of the crushed and pulverized waste slate is formed in a size in a range of 100 meshes to 300 meshes. The detoxified asbestos includes re-crystallized magnesium oxalate having a rhombohedral or amorphous shape.

First claim

What is claimed is:

1. A method of detoxifying asbestos of waste slate, the method comprising:
concentrating the asbestos by introducing hydrochloric acid aqueous solution into waste slate powder to dissolve and remove a limestone component contained in the waste slate; and
mixing the concentrated asbestos with oxalic acid and performing a low-temperature heat treatment to form a magnesium oxalate (MgC 2 O 4 ) having a rhombohedral or amorphous shape,
wherein a mixing ratio (g/cc) of the waste slate powder to the hydrochloric acid aqueous solution is in a range of 1:8 to 1:10 based on 5% hydrochloric acid aqueous solution,
wherein a mixing ratio (g/cc) of the concentrated asbestos to the oxalic acid is in a range of 0.8:0.5 to 1, and
wherein the low-temperature heat treatment is performed at 100° C.

2. The method of claim 1 , wherein the oxalic acid is diluted with at least one selected from the group consisting of water, distilled water and deionized water.

3. A method of detoxifying asbestos of waste slate, the method comprising:
crushing and pulverizing the waste slate containing the asbestos; concentrating the asbestos by introducing hydrochloric acid aqueous solution into powder of the crushed and pulverized waste slate; and mixing the concentrated asbestos with oxalic acid and performing a low-temperature heat treatment,
wherein a mixing ratio (g/cc) of the waste slate powder to the hydrochloric acid aqueous solution is in a range of 1:8 to 1:10 based on 5% hydrochloric acid aqueous solution,
wherein a mixing ratio (g/cc) of the concentrated asbestos to the oxalic acid is in a range of 0.8:0.5 to 1, and
wherein the low-temperature heat treatment is performed at 100° C.

4. The method of claim 3 , wherein the crushing of the waste slate is performed by a jaw crusher or a cone crusher, and
the pulverizing of the waste slate is performed by a pulverizer.

5. The method of claim 3 , wherein the powder of the crushed and pulverized waste slate is formed in a size in a range of 100 meshes to 300 meshes.

6. The method of claim 3 , wherein the oxalic acid is diluted with at least one selected from the group consisting of water, distilled water and deionized water.

Assignees

• Korea Inst Geoscience & Mineral Resources
• Korea Inst Of Geoscience And Mineral Resource

Inventors

• Jang Young-Nam
• Song Kyungsun
• Lee Myung Gyu
• Chae Soo-Chun
• Jo Hwanju
• Bang Jun-Hwan
• Ryu Kyoung Won

Classifications

• B09B3/70

  Chemical treatment, e.g. pH adjustment or oxidation (involving an extraction step B09B3/80) · CPC title

• B09B2101/35

  Asbestos · CPC title

• B09B3/40

  involving thermal treatment, e.g. evaporation (processes using mineral binders involving a melting or softening step B09B3/29; involving radiation B09B3/50) · CPC title

• B09B3/35

  Shredding, crushing or cutting · CPC title

• A62D2101/41

  Inorganic fibres, e.g. asbestos · CPC title