Poly-crystalline compositions

Details Poly-crystalline compositions Poly-crystalline compositions

2002-01-08

2004-11-30

Turner, Archene (Department: 1775)

Compositions: ceramic

Ceramic compositions

C501S004000, C501S032000, C501S053000, C501S057000, C501S068000, C501S070000, C501S073000

Reexamination Certificate

active

06825139

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to poly-crystalline compositions, articles of manufacture and processes for producing same.
BACKGROUND OF THE INVENTION
Ash in the form of coal ash and of municipal solid waste coal ash is a major environmental problem. Coal ash represents an incombustible residual formed from mineral admixtures of coal upon its burning at heat power-stations. The quantity of ash depends on the coal composition and ranges from 5% to 13% of the fuel total. Industrial developed countries, which are producing considerable quantities of electric power, face the problem of accumulating huge quantities of coal ash waste.
Altogether, 20% of the coal ash is bottom ash heavy and light melting particles wherein 80% is coal ash, which has light, thin-dispersion particles.
In most countries, part of the coal ash is used in cement as a substitute for shale; in concrete as a substitute for cement and sand; in road construction as a filler to bitumen and in bricks as a substitute for clay. In spite of the above, large amount of the coal ash are not exploited.
U.S. Pat. No. 5,521,132 by Talmy et al., teaches a method of manufacturing ceramic materials on the base of ash from coal and solid municipal waste incineration, mixed with sodium tetraborate and a calcium containing material.
U.S. Pat. No. 5,583,079 by Golitz, et al., discloses a method of ceramic products obtained by mixing coal ash, glass and clay wastes.
U.S. Pat. No. 3,966,9122 to Miller et al., teaches a method of manufacturing of soda-lime glass containing coal ash.
U.S. Pat. No. 4,430,108 to Hojaji et al., teaches a method of manufacturing foam glass from diatomaceous and coal ash.
U.S Pat. No. 5,935,885 to Hnat et al., teaches a process for forming glass ceramic tiles.
However, the above mentioned inventions provide glass products, which have similar properties to those that are already exist in the market. Moreover, the high quantity of iron in the coal ash paints the glass materials in a black color, which limit their possible applications.
There is thus, a widely recognized need for cost effective processes and for products comprising of high amount of coal ashes. Moreover, it will be highly advantageous to have high quality glass poly-crystalline products e.g. high impact strength, high compressive strength, high bending strength high hardness, modulus of elasticity, thermal-resistance, high-temperature strength, wear-resistance, absence of porosity, zero water-absorption and gas-impermeability and low thermal conductivity.
SUMMARY OF THE INVENTION
In one embodiment, the invention provides a poly-crystalline composition comprising an amount of SiO
2
, Al
2
O
3
, CaO, Fe
2
O
3
, TiO
2
, MgO, Na
2
O, Li
2
O, CeO
2
, ZrO
2
, K
2
O, P
2
O
5
, Cr
2
O
3
, ZnO and MnO
2
.
In another embodiment, the invention provides a process for producing a poly-crystalline composition comprising the steps of: mixing a coal ash particle with at least one glass forming agent and at least one crystallization catalyst; melting said coal ash particle, the at least one glass forming agent and the at least one crystallization catalyst to form a mixture; and cooling the resulting mixture to ambient temperature so as to form a homogenous, non-porous poly-crystalline product comprising SiO
2
, Al
2
O
3
, CaO, Fe
2
O
3
, TiO
2
, MgO, Na
2
O, Li
2
O, CeO
2
, ZrO
2
, K
2
O, P
2
O
5
, Cr
2
O
3
, ZnO and MnO
2
.
In another embodiment, the invention provides an article of manufacture comprising SiO
2
, Al
2
O
3
, CaO, Fe
2
O
3
, TiO
2
, MgO, Na
2
O, Li
2
O, CeO
2
, ZrO
2
, K
2
O, P
2
O
5
, Cr
2
O
3
, ZnO and MnO
2
.
In another embodiment, the invention provides a poly-crystalline product comprising an amount of SiO
2
, Al
2
O
3
, CaO, Fe
2
O
3
, TiO
2
, MgO, Na
2
O, Li
2
O, CeO
2
, ZrO
2
, K
2
O, P
2
O
5
, Cr
2
O
3
, ZnO and MnO
2
.
In another embodiment, the invention provides a poly-crystalline product that is produced by a process comprising the steps of: a. mixing coal ash particle with at least one glass forming agent and at least one crystallization catalyst; b. melting the coal ash particle, the at least one glass forming agent and the at least one crystallization catalyst to form a mixture; and c. cooling the resulting mixture to ambient temperature to form a homogenous, non-porous microcrystalline composition comprising SiO
2
, Al
2
O
3
, CaO, Fe
2
O
3
, TiO
2
, MgO, Na
2
O, Li
2
O, CeO
2
, ZrO
2
, K
2
O, P
2
O
5
, Cr
2
O
3
, ZnO and MnO
2
.
This invention provides a poly-crystalline composition, poly-crystalline product and an article of manufacture which further comprising an amount of 35.0-43.0 percent of SiO
2
, 29.0-36.0 percent of Al
2
O
3
, 1.4-4.1 percent of Fe
2
O
3
, 16.0-21.0 percent of CaO, 1.3-15.2 percent of TiO
2
, 0.6-8.9 percent of K
2
O, 1.4-6.8 percent of P
2
O
5
, 0-6.0 percent of Cr
2
O
3
, 0-11.2 percent of ZnO, 0-1.5 percent of MnO
2
, 0-10.0 percent of MgO, 0-10.2 percent of Na
2
O, 0-5.0 percent of CeO
2
, 0-5.0 percent of ZrO
2
and 0-10.2 percent of Li
2
O by weight.
In another embodiment the invention provides a poly-crystalline composition, poly-crystalline product and an article of manufacture which further comprising an amount of 35.0-57.0 percent of SiO
2
, 15.0-36.0 percent of Al
2
O
3
, 1.4-10.0 percent of Fe
2
O
3
, 15.0-22.0 percent of CaO, 0.6.-15.2 percent of TiO
2
, 0.3-11.0 percent of K
2
O, 1.4-6.8 percent of P
2
O
5
, 0-6.0 percent of Cr
2
O
3
, 0-11.2 percent of ZnO, 0-11.5 percent of MnO
2
, 0-10.0 percent of MgO, 0-10.2 percent of Na
2
O, 0-5.0 percent of CeO
2
, 0-5.0 percent of ZrO
2
and 0-10.2 percent of Li
2
O by weight.
In another embodiment, in step C, the microcrystalline composition further comprising an amount of 35.0-43.0 percent of SiO
2
, 29.0-36.0 percent of Al
2
O
3
, 1.4-4.1 percent of Fe
2
O
3
, 16.0-21.0 percent of CaO, 1.3-15.2 percent of TiO
2
, 0.6-8.9 percent of K
2
O, 1.4-6.8 percent of P
2
O
5
, 0-6.0 percent of Cr
2
O
3
, 0-11.2 percent of ZnO, 0-1.5 percent of MnO
2
, 0-10.0 percent of MgO, 0-10.2 percent of Na
2
O, 0-5.0 percent of CeO
2
, 0-5.0 percent of ZrO
2
and 0-10.2 percent of Li
2
O by weight.
In another embodiment, in step C, the microcrystalline composition further comprising an amount of 35.0-57.0 percent of SiO
2
, 15.0-36.0 percent of Al
2
O
3
, 1.4-10.0 percent of Fe
2
O
3
, 15.0-22.0 percent of CaO, 0.6-15.2 percent of TiO
2
, 0.3-11.0 percent of K
2
O, 1.4-6.8 percent of P
2
O
5
, 0-6.0 percent of Cr
2
O
3
, 0-11.2 percent of ZnO, 0-11.5 percent of MnO
2
, 0-10.0 percent of MgO, 0-10.2 percent of Na
2
O, 0-5.0 percent of CeO
2
, 0-5.0 percent of ZrO
2
and 0-10.2 percent of Li
2
O by weight.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides for obtaining and using coal ash for the production of poly-crystalline compositions or products and in another aspect the invention provides a process for producing same. The invention is particularly applicable to coal ash that contains large amounts of calcium oxide and transition metals such as iron manganese, chromium, titanium and the like.
As used hereinabove the term “bottom ash” or “bottom coal ash” presents itself more coarse (0.2-10 millimeters) pieces of ash which did not sweep away by smoke gases and accumulate in the bottom part of the fire box.
As used here in the specifications and in the claims section the term “fly coal ash” refers to fine solid particles of ash (5-50 &mgr;m) that are carried away by draft or by waste gases and then deposited in flues or trapped in filters or precipitation and the like. The coal ash contain organic materials and metal contaminants.
It should be noted that the term of ash or coal ash hereinabove refer to both fly ash and to bottom ash, unless one of them is stated particularly. As is exemplified in Example 6, both fly ash and bottom ash can be used to prepare the composition and articles of the invention.
In one embodiment of the present invention, there is provided a poly-crystalline composition, a poly-crystalline product and an article of manufacture comprising oxides such as SiO
2
, Al
2
O
3
, CaO, Fe
2
O
3
, TiO
2
, K

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