INSULATING, REFRACTORY MOLDED BODY, ESPECIALLY PLATE, AND PROCESS FOR ITS MANUFACTURE AND ITS USAGE

• US 20190322581A1
• Filed: 06/27/2017
• Published: 10/24/2019
• Est. Priority Date: 06/30/2016
• Status: Active Grant

• Current Assignee: Refratechnik Holding GmbH
• Original Assignee: Refratechnik Holding GmbH
• Inventors: Jansen, Helge, Schemmel, Thomas, Stein, Petra, Scholwer, Michael
• Granted Patent: US 11,148,973 B2
• Time in Patent Office: Days
• CPC Class Codes: B22D 41/02 Linings
• CPC Class Codes: B22D 7/102 from refractorial material only
• CPC Class Codes: C04B 14/062 Microsilica, e.g. colloïdal silica preparing microsilica slurries or suspensions C04B18/148
• CPC Class Codes: C04B 18/101 Burned rice husks or other burned vegetable material
• CPC Class Codes: C04B 20/0076 characterised by the grain distribution
• CPC Class Codes: C04B 2111/00431 Refractory materials
• CPC Class Codes: C04B 2111/0087 for metallurgical applications
• CPC Class Codes: C04B 2111/00887 Ferrous metallurgy
• CPC Class Codes: C04B 2111/1025 Alkali-free or very low alkali-content materials
• CPC Class Codes: C04B 2111/1031 Lime-free or very low lime-content materials
• CPC Class Codes: C04B 2111/28 Fire resistance, i.e. materials resistant to accidental fires or high temperatures
• CPC Class Codes: C04B 2111/40 Porous or lightweight materials
• CPC Class Codes: C04B 2111/763 High temperatures
• CPC Class Codes: C04B 2201/20 for the density
• CPC Class Codes: C04B 2201/30 for heat transfer properties such as thermal insulation values, e.g. R-values
• CPC Class Codes: C04B 2201/50 for the mechanical strength
• CPC Class Codes: C04B 28/24 containing alkyl, ammonium or metal silicates; containing silica sols reaction mixtures resulting in mineral polymers C04B28/006; polymeric reaction products of alkali metal silicates with isocyanates C08G18/3895
• CPC Class Codes: C04B 38/0074 expressed as porosity percentage
• CPC Class Codes: C04B 40/0028 Aspects relating to the mixing step of the mortar preparation
• CPC Class Codes: C04B 40/0067 making use of vibrations
• CPC Class Codes: C04B 40/0071 : making use of a rise in pressure
• CPC Class Codes: Y02W 30/91 : Use of waste materials as fillers for mortars or concrete

Abstract

An unfired, refractory molded body (1), especially a plate, especially for thermal insulation of molten metal and/or an ingot solidifying from molten metal, that includes a binding agent matrix (2) of a set binder and aggregate grains (3) of biogenic silicic acid, preferably of rice husk ash, which are incorporated into the binding agent matrix (2), wherein the binding agent matrix (2) consists of silica gel, as well as a process for its production and its usage.

Claims

1. An unfired, refractory molded body (1), especially plate, especially for thermal insulation of molten metal and/or an ingot (14) solidifying from molten metal, comprising a binding agent matrix (2) of a set binding agent and aggregate grains (3) of biogenic silicic acid, preferably of rice husk ash, which are incorporated into the binding agent matrix (2), characterized in that the binding agent matrix (2) is comprised of silica gel.

2. The molded body (1) according to claim 1, characterized in that the biogenic silicic acid is rice husk ash and/or diatomaceous earth and/or silica shale and/or diagenetically fossilized radiolaria skeletons or opal sponges.

3. The molded body (1) according to claim 1, characterized in that the aggregate of the molded body (1) is comprised of at least 50 wt. %, preferably of at least 80 wt. %, more preferably of at least 90 wt. %, especially preferably 100 wt. % of biogenic silicic acid, preferably of rice husk ash, with respect to the total dry mass of aggregate materials.

5. The molded body (1) according to claim 1, characterized in that the molded body (1) has a dry apparent density ρ

₀ from 0.3 to 1.5 g/cm³, more preferably from 0.5 to 1.3 g/cm³ according to DIN EN 1094-4 (09/1995).

6. The molded body (1) according to claim 1, characterized in that the molded body (1) has a porosity of 60 to 90%, preferably from 70 to 80% according to DIN EN 1094-4 (09/1995).

7. The molded body (1) according to claim 1, characterized in that the molded body (1) has a cold compression strength of 0.5 to 15.0 MPa, preferably of 1.0 to 10.0 MPa according to DIN EN 993-5 (12/1998).

8. The molded body (1) according to claim 1, characterized in that the molded body (1) has a cold bending strength of 0.3 to 7.0 MPa, preferably of 0.5 to 5.0 MPa according to DIN EN 993-6 (04/1995).

9. The molded body (1) according to claim 1, characterized in that the molded body (1) has a hot bending strength of 0.5 to 5.0 MPa, preferably of 1.0 to 3.0 MPa according to DIN EN 993-7 (04/1995).

10. The molded body (1) according to claim 1, characterized in that the molded body (1) has a softening point, determined with a heating microscope according to DIN EN 51730 (09/2007), of 1500 to 1700°

C., preferably of 1650 to 1700°

C.

11. The molded body (1) according to claim 1, characterized in that the molded body (1) has the following thermal conductivities according to DIN EN 993-15 (07/2005):

13. A process for producing a molded body (1) according to claim 1, characterized by the following steps:

a) Producing of a mixture comprising the biogenic silicic acid and silica sol,

b) Filling the mixture into a mold,

c) Compacting of the mixture,

d) Demolding the green molded body (1), and

e) Allowing the molded body (1) to set.

14. The process according to claim 13, characterized in that the composition of the mixture is adjusted such that the mixture has a slump—

determined in reference to DIN EN ISO 1927-4 (03/2013)—

of 200 to 500 mm, preferably 250 to 350 mm.

15. The process according to claim 13, characterized in that the mixture has the following composition in relation to the total dry mass, wherein the individual components add up to 100 wt. %:

16. The process according to claim 13, characterized in that the aggregate grains (3) of biogenic silicic acid are agglomerated with water and/or silica sol into granulate grains before mixing with the remaining components of the mixture, and the granulate grains are mixed with the remaining components of the mixture in a ductile state.

17. A use of a molded body (1) according to claim 1 for thermal insulation of molten metal, especially molten steel, and/or a metallic ingot (14) solidifying from the molten metal, preferably in steel production.

18. The use according to claim 17, characterized in that the molded body (1) is used for thermal insulation of the molten metal, particularly the molten steel, within a metallurgical vessel, and/or an ingot (14) within a metallurgical vessel, from the vessel and/or from the atmosphere.

19. The use according to claim 17, characterized in that the molded body (1) is used for thermal insulation of the molten metal, particularly of the molten steel, and/or of the ingot (14) in rising ingot casting.

20. The use according to claim 19, characterized in that the molded body (1) is used for thermal insulation of an ingot head (15) of the ingot (14).

21. The use according to claim 17, characterized in that the molded body is used as a cover plate (10) for covering and thermally insulating a metal bath (8), particularly a steel bath, within an ingot mold (7).

22. The use according to claim 17, characterized in that the molded body is used as a cover plate (19) for covering and thermally insulating a metal bath ((8), particularly a steel bath, within a casting distributor (20).

23. The use according to claim 21, characterized in that the cover plate (10;

19) is used for covering the metal bath (8) within the ingot mold (7) or the casting distributor (20) in rising or falling ingot casting.

24. A use of a molded body (1) according to claim 1 for thermal insulation of a refractory lining, especially in multi-layer masonry or in heat-treatment ovens or as a corrosion barrier, for example against alkali attack, or as a fire protection lining or as filter material for hot gases.

4. (canceled)

12. (canceled)