Method for making glass silicate tiles

• US 5,900,202 A
• Filed: 09/26/1997
• Issued: 05/04/1999
• Est. Priority Date: 09/26/1997
• Status: Expired due to Fees

• Current Assignee: Marina Lingart, Stanislav Lingart, Youri Lingart
• Original Assignee: Marina Lingart, Stanislav Lingart, Youri Lingart
• Inventors: Lingart, Youri, Lingart, Marina, Lingart, Stanislav
• Primary Examiner(s): Fiorilla, Christopher A.
• Application Number:
  US08/938,728
• Time in Patent Office: 585 Days
• Field of Search: 264/113, 264/125
• US Class Current: 264/113
• CPC Class Codes: B28B 11/24 for curing, setting or hardening processes for influencing or modifying the setting or hardening ability of mortars, concrete or artificial stone compositions, in general C04B40/00
• CPC Class Codes: C03B 19/06 by sintering, e.g. by cold isostatic pressing of powders and subsequent sintering, by hot pressing of powders, by sintering slurries or dispersions not undergoing a liquid phase reaction
• CPC Class Codes: C03B 19/09 by fusing powdered glass in a shaping mould
• CPC Class Codes: F27B 2009/266 the truck having conducts for guiding the oven atmosphere
• CPC Class Codes: F27B 9/262 on or in trucks
• CPC Class Codes: F27B 9/3005 arrangements for circulating gases
• CPC Class Codes: F27B 9/36 Arrangements of heating devices
• CPC Class Codes: F27D 3/123 Furnace cars

Abstract

A method of making glass-silicate tiles includes pouring an input raw material containing glass granulate into a heat-proof mold, wetting the input raw material and making an initial blank thereby, heat treating of the blank by gradual heating and by gradual cooling by stages with holding period between the stages wherein a first heating stage is performed predominantly by heating a bottom side of the blank with higher speed of heating of a lowering layer than of an upper layer of the blank to accelerate gases to release the blank through the upper layer up to reach of the temperature of beginning of glass granulate sintering (T_f) in the lower layer, and the temperature not exceeding a glass granulate transformation temperature (T_g) in the upper layer, a first holding period at these condition to expel generated gases, and heating the upper layer with higher speed than the lower layer until a Littleton temperature is reached in the lower layer.

Claims

1. A method of making glass-silicate tiles comprising the steps of:

(a) pouring an input raw material containing glass granulate into a heat-proof mold, wetting the input raw material and making an initial blank thereby;

(b) heat treating of the blank in the heat-proof mold by gradual heating and by gradual cooling by stages with holding period between the stages wherein;

(i) a first heating stage is performed predominantly by heating a bottom side of the blank with higher speed of heating of a lower layer than of an upper layer of the blank to accelerate gases to release through the upper layer and to reach the temperature of beginning of glass granulate sintering (T_f) in the lower layer, and the temperature not exceeding a glass granulate transformation temperature (T_g) in the upper layer,

(ii) a first holding period at these conditions to expel generated gases, and

(iii) heating the upper layer with higher speed than the lower layer until a Littleton temperature is reached in the lower layer.

2. The method of claim 1 wherein a temperature gradient equal to the temperature difference between the lower and upper layer being maintained within 150-300°

C. for the first holding period (Δ

T=T_f -T_g).

3. The method of claim 1 wherein a second holding period being done after achievement of the Littleton temperature in the lower layer and the sintering temperature in the upper layer during which a temperature gradient is maintained on the level that equals to the temperature difference between the lower and upper surfaces within 30 to 70°

C. (Δ

T=T_L -T_f).

4. The method of claim 3 wherein the blank is pressed from above by a gas permeable unit with a surface temperature of said unit equal to the temperature of the upper layer surface in the period of the second holding period.

5. The method of claim 3 wherein an additional blank heating being performed after the second holding period until the upper layer temperature reaches T_max corresponding to a glass granulate viscosity logarithm 4±

₁.5⁰.5 Pa.s on which a third holding period is made until the lower layer reaches the temperature on which the glass granulate logarithm is equal to 5±

0.5 Pa.s, after which the stage-by-stage cooling process begins.

6. The method of claim 5 wherein a first cooling stage being performed until temperature T_L is reached on the blank surface, and the first holding period is realized on cooling until the lower layer reaches the same temperature T_L.

7. The method of claim 6 wherein a second stage--cooling--is realized after the first stage--holding period--until the high annealing temperature T₁₂ is reached, on which the glass granulate viscosity logarithm is equal to 12 Pa.s on which the second stage of holding period is realized for product annealing.

8. The method of claim 7 wherein a third stage of cooling is realized after the annealing to the low annealing temperature T₁₃.5 on which the glass granulate viscosity logarithm is equal to 13.5 Pa.s, after which the third stage of holding period is realized with the temperature to remove a residual thermal stress, while the product is cooled down to a room temperature after the second annealing.

9. The method of claim 8 wherein the third cooling stage is performed in conditions of linear tile temperature decreasing in time.

10. The method of claim 7 further comprising an additional holding period before the second stage holding period between the Littleton and a high annealing temperatures, when the blank surface is treated by a reagent containing cations of lithium.

11. The method of claim 1 wherein the blank is made of three poured layers:

a lower layer of granulated scrap glass thick 3 to 4 mm with maximum size of the granules 2 to 3 mm;

the second one consisting of a mixture of silicate material and granules of window scrap glass; and

the upper layer which is the mixture of colorless ad colored glass granulate thick 3 to 5 mm.

12. The method of claim 11 wherein coloring metal oxides are added in the upper layer.

13. The method of claim 1 wherein the blank is made of two poured layers:

the lower layer comprising of the mixture of fine-dispersed silicate material and scrap glass, and the upper layer comprising glass granulate, while the silicate material temperature does not reach the silicate material melting or softening temperature in the lower layer in course of heating.

14. The method of claim 1 wherein the blank is made of a single layer of poured glass granulate of required thickness.

15. The method of claim 1 wherein the blank is made of three poured layers:

the lower and upper layers of glass granulate of an identical composition, and the middle layer of the glass granulate of different composition which thermal expansion coefficient is higher than the thermal expansion coefficient of both the upper and lower layers.

16. The method of claim 1 wherein the blank is formed by three layers:

the lower and upper layers of glass granulate of identical composition, and the medium layer of glass granulate which Littleton temperature is lower than the Littleton temperature of the upper and lower layers.

17. The method of claim 1 wherein 3 to 7% (by weight) of water glass is added additionally into the blank which is then blown with carbon dioxide with the temperature 150 to 200°

C.

18. A method of making the glass-silicate tiles comprising:

(a) creating of an initial blank by pouring an initial raw material containing glass granulate into a heat-proof mold and its consolidating;

(b) gradual heating the blank in the heat-proof mold with holding periods between stages comprising following stages;

a first stage of heating, predominantly from bottom of the blank with lower layer heating temperature higher than the temperature of upper layer to accelerate gas removal through the upper surface layer until a glass granulate sintering temperature is reached in the lower layer, a first holding period at these conditions to expel generated gases, heating the upper layer with higher speed than the lower layer until a Littleton temperature is reached in the lower layer and sintering temperature is reached in the upper layer and having a second holding period with these conditions, during the second holding period pressing the blank by a gas permeable press, after which additionally heating the blank until the upper layer reaches a temperature T₄,5 corresponding to 4.5 Pa.s, under which the third holding period is realized until the lower layer reaches a temperature T₅,5 on which a glass granulate viscosity logarithm is equal to 5.5 Pa.s;

(c) after the third holding period the blank is cooled in the heat-proof mold with holding periods between following stages;

a first stage of accelerated cooling is realized until the blank surface reaches a temperature T_L, which is followed by a holding period for the period of time sufficient to achieve the Littleton temperature in the lower layer;

after the first holding period a second cooling stage is performed until the annealing temperature is reached, after which a second holding period ensures a product annealing;

after the first annealing a third cooling stage is realized until the surface reaches a temperature T₁₃,5 on which the melt viscosity logarithm is equal to 13.5 Pa.s, after which the product is annealed, and, after the second annealing, cooled down to the room temperature.

19. The method of claim 18 wherein the blank is formed by three poured layers:

the lower layer containing the granulated window glass scrap thick 3 to 4 mm with maximum size of granules 2 to 3 mm, the middle layer consisting of the mixture of silicate material and granulated glass scrap, and the upper layer which is a mixture of window or bottle and colored glass thick 3 to 5 mm.

20. The method of claim 19 wherein coloring metal oxides are added into the upper layer.

21. The method of claim 19 wherein fine-dispersed sand is used as the silicate material.

22. The method of claim 18 wherein the blank is made of two poured layers:

the lower layer comprising a mixture of fine-dispersed silicate material and scrap glass of different composition, and the upper layer comprising the glass granulate, while the lower layer silicate material temperature does not reach the melting or softening temperature in course of heating.

23. The method of claim 18 wherein the blank is formed by a single layer of poured glass granulate of required thickness.

24. The method of claim 18 wherein the blank is formed by three poured layers:

the lower and upper layers of the same composition, and the middle layer of glass granulate of other composition which thermal expansion coefficient is higher than the thermal expansion coefficient of the upper and lower layers.

25. The method of claim 18 wherein the blank is formed by three poured layers:

the lower and upper layers of glass granulate of any composition, and the middle layer of glass granulate which Littleton temperature is lower than the Littleton temperature of the upper and lower layers.

26. The method of claim 18 wherein 3 to 7% (by weight) of water glass is added in the blank, and the blank is blown with carbon dioxide with temperature 150 to 200°

C. after pressing.

27. The method of claim 18 wherein there is an additional holding period in the cooling stage between the Littleton temperature and high annealing temperature, when the blank surface is treated by a reagent containing cations of lithium.