Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02664990 2009-04-29
Composition and Methods of Producing Glass and Glass-Ceramic Materials From
Manganese
Tailings
The present invention relates to novel glasses and glass-ceramics made from
manganese nodules,
crust and stratified ore tailings with added silica and fluxing agents by
producing glasses that are
also precursors of resultant glass-ceramics. In addition, the invention
relates to novel glass-ceramics
and methods of heat treating the precursor glasses to produced the glass-
ceramics and relates to
potential commercial applications of said resultant glasses and glass-
ceramics.
Background Of The Invention
Manganese crust and nodule deposits have been extensively studied as potential
mineral
sources, especially for the very valuable minerals cobalt and palladium, while
manganese ore has
been mined from stratified deposits for many years. Tailings waste resulting
from processing of
manganese crust and nodules ore in a commercial or dressing plant will require
treatment to
decrease volume and potential toxicity. The nearest potential land-based
processing plants for these
ore deposits mined in the South Pacific would be on small, environmentally-
sensitive islands. It is
extremely unlikely that the main existing method of tailings treatment (i.e.
tailings impoundment)
would be an acceptable approach on these islands, where geographic space is
very limited,
aesthetics are crucial to commerce and the indigenous people hold nature in
high regard.
Impoundment also does nothing to diminish tailings volume. Recycling and reuse
would be the
optimal approach based largely upon economic feasibility. Even if tailings
impoundment was
acceptable under intense scrutiny, this method poses serious risks from
possible groundwater
pollution due to leachates, and potential for catastrophic dam failure.
Vitrification has been proven to be an effective method of converting waste
materials into
useful products and treating; hazardous radioactive wastes, industrial wastes
such as fly ash and
other industrial wastes. In addition, vitrification has been shown to be a
useful method for treating
hazardous mineral ore tailings and thus, a possible alternative approach to
tailings impoundment,
which would be especially applicable to regions where land surface area is at
a premium and the
environmental and natural aesthetics are considered very important to the
local population.
Commercial glass is primarily made of, (a) a glass former like silica, (b)
alkalis like soda
and potash to change the state from solid to liquid, (c) stabilizers like CaO,
MgO and A1203 to
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CA 02664990 2009-04-29
reduce weathering, (d) refining agents like Na2O, K2O and CaSO4 to remove
bubbles, and small
quantities of other additives to give different characteristics to the glass.
Development of a glass
formulation for waste materials represents a challenge with respect to
optimizing; (a) waste
acceptability, (b) melt processability, (c) glass product durability, and (d)
overall economics. The
acceptability criterion is essential for the product to function as a barrier
against the release of heavy
metals or other hazardous wastes into the environment.
McMillan suggested that silica is not always the major former, since boric
oxide has
partially or completely replaced silica oxide to produce glasses that exhibit
flow characteristics,
which make them suitable for special applications. Pelino et al. reported the
higher the silica content
in the raw materials, the higher the melting temperature. Barbieri et al.
suggested that suitable
glasses can only be obtained if a satisfactory ratio between glassy network
formers and modifiers
exists. In addition, the authors described how transition oxides acted as
nucleants in a calcium
aluminosilcate glass. Common fluxes (e.g. Na2O, K2O, Li02 and B203) can reduce
the melting
temperature of silicate melts, where the melting point of silica is usually
(>2000C), although adding
large amounts of alkali fluxes can degrade chemical durability. Fortunately,
this may be offset by
adding modifiers such as A1203 or transition element oxides such as Fe2O3 or
Mn02.
The viscosity of a glass melt, as a function of temperature, is the most
important variable
affecting the melting rate and pourability of the glass. The viscosity
determines the rate of melting
of the raw feed, the rate of gas bubble release (foaming and fining), the rate
of homogenization, and
thus the quality of the final glass product. Barbieri et al reported that
melts containing higher
alumina content (>15wt%) have displayed higher viscosity values. Volatility of
the melt (foaming)
relates to the rate and amount of bubble release, the degree of homogenization
and thus the quality
of the final glass product.
The slowest cooling rate that produces a glass is deemed the critical cooling
rate. Glass
stability is often characterized by the difference between the onset of the
glass transition region (Tg)
and the first occurrence of a crystallization peak (Tp). Lack of distinct
exothermic peaks may be
taken as lack of crystallization. Acosta et al. reported that power plant
derived glass was considered
stable due to lack of clear exothermic peaks in the DTA curve. Shelby reported
that in glasses with
(Tds - Tg) <50K, phase separation often occurs. Also that, slow cooling of
glass melts tends to
diminish the occurrence of thermal shock and weakening of the glass.
The Vickers microhardness of known oxide glasses ranges from 2 to 8 GPa, while
a
theoretical strength (Kc) of 32GPa is typical for silicate glasses. Due to
flaws in glass surfaces,
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CA 02664990 2009-04-29
actual strengths are much lower. Alumina ions replacing modifier ions in
silicate glass reduce the
number of non-bridging oxygen ions, which increases the connectivity of the
network and
subsequently increases the elastic modulus. Since (E) is related to bond
strength, it follows that
glasses with high glass transformation temperatures usually have high (E)
values. The optimal
thermal shock resistance is found in low expansion (low a) and low modulus
(low E) glasses.
Commercial glasses must be resistant to the environment in which they are
used. The main
factors controlling the rate and mechanism of attack on silicate glasses by
aqueous solutions are;
glass composition, pH of the solution, and the temperature. Chemical
resistance of waste glasses is
directly related to the extent these glasses resist chemical reactions with
water and associated
chemicals. Waste glasses undergo a variety of complex changes in aqueous
environments, which is
referred to as glass corrosion or glass dissolution. As industrial materials,
glasses should have
acceptable durability, which is often linked to high mechanical strength.
Sheng et al reported that
using minimum additives, lowering process temperature, decreasing waste volume
and producing
marketable products are major factors affecting overall economics of turning
waste into glass.
Glass-ceramics are fine-grained polycrystalline materials formed when glasses
of suitable
composition are heated and undergo controlled crystallization. Not all glasses
can be crystallized
into acceptable glass, since some are too stable and difficult to crystallize,
while others crystallize
too readily and form unacceptable crystal structures. Glass-ceramics are
normally only 50 to 98%
crystallized, while the composition of the crystalline phase (or phases) is
normally different from
the parent glass. The advantage of glass-ceramics over glasses, are their ease
of fabrication and
superior properties.
To achieve an optimal glass-ceramic, the crystalline process must be
controlled to produce
the desired microstructure, usually through a two-step (thermal molten process
or TMP) heating
process. This approach transforms the parent glass into a composite material
in which the crystalline
phase is bonded by the residual phase. The first step in the TMP approach at
lower temperatures,
involves the formation of heterogeneous nuclei (small crystallites of size
range 10 to 100nm to
promote the growth of the major crystal phase. The greater the number of
nuclei formed, the finer
the structure of the glass-ceramic and the more acceptable the properties of
the material. Thus, the
presence of an efficient nucleating agent in the correct concentration and the
determination of the
temperature and time of nucleation and growth, assume specific importance in
glass-ceramic
formation.
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This study considers the control of potential crystalline phases in glass-
ceramics derived
from manganese ore tailings. The two approaches employed were (a) adjusting
the chemical
composition of the raw tailings with additives and (b) controlling the
crystalline phases by
optimizing the heat treatment schedule. The physical and chemical properties
of the resulting glass-
ceramics were compared to known materials as an indication of achieving
suitable conditions for
glass-ceramic production.
The invention is directed to glass and glass-ceramic products made from
manganese tailings,
silica and fluxes; raw batch formulations for making these glass and glass-
ceramic products; and
methods for making these glass and ceramic products. The invention provides a
low-cost method of
producing glass and glass-ceramic products from raw waste materials. A wide
variety of glass and
glass-ceramic products can be manufactured by the invention.
The invention also addresses several current problems: energy usage by the
ceramic industry
needs to be reduced; new recycled-glass products are needed and a relatively
economical and
environmentally sensitive method of disposing of manganese ore tailings is
required. The ceramic
industry consumes large amounts of energy, especially during the firing
process. Firing
temperatures greater than 1200 C. (2200 F.) are required to sinter typical
ceramic raw materials
into dense products. Use of fluxes has led to reductions in firing
temperatures, in the general
ceramic industry, but the improvements are limited because of the types of raw
materials used. Most
traditional ceramic products, such as tile and brick, consist mainly of clay-
based raw materials,
which inherently require high firing temperatures. Other ceramic manufacturing
steps, such as the
drying processes, are also very energy intensive. Energy costs are a major
portion of the total
manufacturing costs and vitrification is also an expensive process, hence new
methods to reduce
the amount of energy required will be of a great benefit to the ceramic and
waste recycling
industries. Thus, reduction in firing temperatures and limiting the length of
the manufacturing
process are important advancements in waste recycling.
New products utilizing recycled waste materials are needed to further promote
waste
recycling. Recent research has been conducted and products have been developed
using recycled
tailings as a glass and ceramic raw material. Past researchers have
demonstrated that it was possible
to vitrify various ore tailings with or without additives. These previous
works have not dealt with
the management of manganese tailings as a waste product and whether they can
be vitrified into
new, glass and glass-ceramic materials, which may have commercial uses that
offset disposal costs.
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CA 02664990 2009-04-29
Description of Prior Art
The use of vitrification to convert various types of waste materials into new
materials are outlined
in the following Canadian, US and Foreign patents and references.
Canadian Patent Documents
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5895511 April, 1999 Tikhonova
5830251 Nov., 1998 Simpson
5792524 Aug., 1998 Lingart et al
5672146 September 1997 Aota
5633090 May 1997 Rodek et al.
5616160 April 1997 Alexander et al.
5588977 December 1996 Pavlov et al.
5583079 Dec., 1996 Golitz et al
5521132 May 1996 Talmy et al
5516595 May 1996 Newkirk et al
5508236 April 1996 Chiang et al.
5424042 June 1995 Mason et al.
5403664 April 1995 Kurahashi et al.
5369062 November 1994 Chiang et al
CA 02664990 2009-04-29
5369062 November 1994 Chiang et al
5350716 September 1994 Beall et al.
5346549 September 1994 Johnson
5312787 May 1994 Uchida et al.
5304708 April 1994 Buehler
5273566 December 1993 Balcar et al.
5273566 December 1993 Balcar
5250474 October 1993 Siebers
5237940 August 1993 Pieper
5230845 July 1993 Hashimoto et al.
5222448 June 1993 Morgenthaler et al.
5220112 June 1993 Bucci
5210057 May 1993 Haun et al.
5210057 May 1993 Hann et al.
5203901 April 1993 Suzuki et al.
5203901 April 1993 Suzuki et al.
5190895 March 1993 Uchida et al.
5188649 February 1993 Macedo et al.
5188649 February 1993 Macdo et al.
5177305 January 1993 Pichat
5175134 December 1992 Kaneko et al.
5175134 December 1992 Kaneko et al.
5061308 October 1991 Murakami et al.
5035735 July 1991 Pieper et al.
5035735 July 1991 Pieper et al
5028567 July 1991 Gotoh et al.
5008053 April 1991 Hashimoto et al.
4988376 January 1991 Mason et al.
4985375 January 1991 Tanaka et al.
4957527 September 1990 Hnat
4944785 July 1990 Sorg et al.
4892846 January 1990 Rogers et al.
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CA 02664990 2009-04-29
4853350 August 1989 Chen et al.
4764486 August 1988 Ishihara et al.
4755489 July 1988 Chyung et al.
4735784 April 1988 Davis et al.
4735784 April 1988 Davis
4678493 July 1987 Roberts et al.
4666490 May 1987 Drake
4666490 May 1987 Drake
4634461 January 1987 Demarest et al
4621066 November 1986 Nishigaki et al.
4544394 October 1985 Hnat
4544394 October 1985 Hnat
4540671 September 1985 Kondo et al
4467039 August 1984 Beall et al.
4444740 April 1984 Snodgrass et al.
4414013 November 1983 Connell
4414013 November 1983 Connell
4299611 November 1981 Penberthy
4271109 June 1981 Boyce
4113832 September 1978 Bell et al.
4113832 September 1978 Bell et al
4112033 September 1978 Lingl
4042362 August 1977 MacDowell et al.
4009015 February 1977 McCollister
3967971 July 1976 Eppler
3955990 May 1976 Tochon
3942966 March 1976 Kroyer et al.
3942966 March 1976 Kroyer et al.
3928047 December 1975 Kapolyi et al
3926648 December 1975 Miller
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CA 02664990 2009-04-29
Foreign Patent Documents
409077530 Mar., 1997 JP
6-247744 Sep., 1994 JP
4254433-A Sep., 1992 JP
4254436-A Sep., 1992 JP
920609390B Sep., 1992 JP
4338131-A Nov., 1992 JP
92076939-B Dec., 1992 JP
1671624-Al Aug., 1991 SU
1701661-Al Dec., 1991 SU
85100521 Aug., 1986 CN
60103-072 Jun., 1985 JP
992475 Jan., 1983 SU
937414 Jun., 1982 SU
113830 Nov., 1982 PL
8005-919 May., 1982 NL
56-5710-B Feb., 1981 JP
895945 Jan., 1981 SU
881042 Nov., 1981 SU
833824 May., 1981 SU
2114017 Oct., 1971 DE
1195931 Jun., 1970 DE
1153388 May., 1969 GB
1557957 Feb., 1969 FR
1163873 Sep., 1969 PL
1167812 Oct., 1969 GB
986289 Mar., 1965 GB
1.368.607 Jan., 1964 FR
96406 Jul., 1960 NL
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Liao, Q., Lu, Z., Tan, K. (1997). Study on manufacturing of glass-ceramic
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Park, K., Hong, S.W., Choi,Y.Y., Kim, B.G., Park, J.S.(1998). Utilization of
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None of this prior art has addressed the problem of minimizing the volume or
stabilizing manganese
tailings or producing new marketable products by heat treating these tailings.
Summary Of The Invention
It is an object of the invention to provide new glasses and glass-ceramic
materials, which
exhibit excellent strength, fracture toughness, hardness, relatively low TEC
and acceptable bending
strength and chemical resistance compared to known commercial materials. The
invention provides
a method to transform large quantities of tailings into useful glass and
ceramic products by a
relatively low-cost, environmentally friendly production process. The major
steps of the method
involve combining waste materials with a flux; melting the mixture to form a
liquid melt; cooling to
room temperature or below the melting temperature; then heating to a
nucleation temperature and
holding for a prescribed time; then heating to a crystallization temperature
and holding for a
prescribed time, and then cooling to room temperature to form a ceramic
product. The method
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CA 02664990 2009-04-29
improves strength compared to glasses formed from the same raw materials. In
addition, the
invention provides a method to sinter silicate parent glasses derived from Mn
tailings and flux
mixtures to produce useful glass-ceramic products.
Brief Description Of The Drawings
Not available.
Detailed Description Of The Invention
The major steps of the invention involve combining waste materials, such as
manganese
tailings, and sometimes silica, with various fluxes, melting the resulting
mixtures to form a liquid
melt, cooling the melt to room temperature or quenching to form glasses and
using the resultant
glasses as precursors to produce glass-ceramic materials employing several
heat treatment methods.
The invention represents the first attempt to reduce the volume of manganese
ore tailings and
subsequently produce commercially useful glasses and glass-ceramic products
from these waste
materials in a relatively economical and environmentally sensitive manner.
Manganese tailings from crust, nodule and stratified ores have been
successfully recycled
into glass and glass-ceramic materials using vitrification technology. Up to
80% incorporation of
the nodules tailings, 70% crust tailings and 60% of stratified ore tailings
has been achieved to
produce glass and glass-ceramics materials, with the optimal working content
being considered
closer to 50%. Volume reductions of greater than 27% for slimes tailings, over
38% for nodules
tailings and 25% for stratified tailings were determined for a one hour
melting duration. It was
established by XRD and scanning electron microscope investigations that the
parent glasses
according to the invention are free from crystals or have minimal
crystallites. Different glass phases
can be present according to a variance in the quantity of components or
application of the heat
treatments. These regions or phases are recognizable using the electron
microscope as small
droplets or phase-in-phase regions.
Hardness, strength and chemical durability are the main characteristics that
determine the
acceptability and usefulness of glasses and glass-ceramics from waste
materials. The high
manganese content glass-ceramics exhibit values of density, Vickers hardness
(H,,), fracture
toughness (Kr) and elastic modulus (E) higher than those of several commercial
glasses and are
similar to ceramics produced in other recycling studies. The chemical
resistances of the glass and
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glass-ceramic products were also within the range of known industrial products
and the established
literature. The chemical crystalline compound produced from the crust tailings
was identified as a
manganese iron silicate, while the nodule tailings apparently produced a two-
phase crystalline
structure containing manganese oxides braunite and hausmannite. The stratified
ore based glass was
identified as the manganese oxide pyrolusite. All crystallized tailings
mixtures appeared to contain a
residual amorphase phase, possible derived from the boron content. The
moderate to high iron
content of these tailings created bloating effects and presented numerous
problems for processing
on a small scale, but on a larger scale these difficulties may be overcome
such that the bloating
effect may be useful in producing marketable porous products on a competitive
basis.
The glasses and glass-ceramics produced were designed to be the least-cost
materials, such
that additional processing steps and lowering the tailings content of the
product mix would
undoubtedly produce higher quality products, although, at a higher cost.
Comparison of study
materials characteristics with known similar materials indicates that these
manganese silicates could
be employed competitively to produce numerous marketable products. Using
materials and
production costs of $446/tonne as the break-even point, several potential
products would return
income to a vitrification operation. In particular geographic locales such as
the Hawaiian or South
Seas islands where the impoundment method is illegal or unacceptable, the
vitrification method
appears a competitive alternative, particularly if energy costs can be
minimized. Other applications
of this approach would be analyzed on a site by site basis.
Specifically, the present invention provides parent glasses and glass-ceramics
consisting of
essentially the same raw components, which can be processed at relatively low
temperatures by
several methods. In order to replace known materials, such as construction
materials, new materials
should display improved characteristics such as increased hardness, strength
and toughness. Glasses
may also be required for specific applications requiring particular
porosities. According to the
investigations, it is absolutely necessary to add a source of flux (i.e.
borax, boric acid, lithium
tetraborate, borosilicate waste glass) to the raw sample chemical composition,
whereby the flux and
glass forming agents in the various mixtures act to promote glass and glass-
ceramic development. In
addition, numerous types of glass and glass-ceramics can be produced by heat
treating the same
chemical compositions, with additions of various fluxes and SiO2 in the form
of quartz sand grains.
The chemical composition of raw tailings and fluxes are displayed in Table A.
The waste glass
employed was discarded laboratory glass, which is classed as a borosilicate
glass.
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Table A. Chemical composition of tailings borax boric acid lithium tetraborate
and waste glass
(wt.%).
Component Nodules Crust Borax Boric acid Lithium tetraborate Waste glass
SiO2 15.54 28.1 80.6
A1203 1.36 20.3 2.2
Fe2O3 1.36 5.6 0.002 0.04
Mn02 44.45 36.0
TiO2 0.39 0.48
B203 36.47 36.47 62.10 12.6
Na2O 16.47 16.47 4.2
K2O 1.30 0.34
CaO 1.14 0.04 0.1
MgO 0.05
Cr2O3
Li2O 5.36
H2O est.15% 8.36 46.57 46.57 32.54
C 0.16 ----
LOI 15-27% ----
Others 5.0 0.40 0.49 0.50 0.1
The manganese tailings may be the result of beneficiating manganese nodules
and
manganese crust ores or manganese ore mined from an underground stratigraphic
sequence.
Tailings are a waste material, hence there is an expected variance in grain
size and percentage
composition of the raw materials employed in the process of preparing glasses
and glass-ceramics.
The parent glass according to the invention is preferably produced by melting
suitable
starting materials, such as oxides and carbonates at a temperature range from
1100 to 1180C, over a
period of 30 minutes to 2 hours, preferably for one hour, with the formation
of a homogeneous melt.
The melt may be quenched in water (i.e. fritted), and the obtained glass
granulate ground up after
drying, or the melt is permitted to cool slowly in air, or the melt is
subjected to further heat
treatment using a 2-step heat treatment method.
The glass-ceramic according to the invention is produced in particular by
subjecting the
obtained granulate of the parent glass according to the invention to thermal
treatment at a
temperature in the range from 600 to 900C for a period of 30 minutes to 4
hours, preferably 30
minutes to 2 hours. Prior to the heat treatment, the parent glass is
preferably ground to a powder
having a grain size less than 90um when sieved.
The raw materials plus flux (i.e. borax, boric acid, lithium tetraborate,
borosilicate waste
glass) are heated (ex. Petrurgic method) at a temperatures up to 11 80C and
held at the mixture
CA 02664990 2009-04-29
melting temperature for 30 min to 2 hours. The melt is then permitted to cool
slowly at a
temperature between 1 and 3C per min to room temperature to form a glass or
glass-ceramic,
dependent upon the materials present.
The raw materials plus flux (i.e. borax, boric acid, lithium tetraborate, and
borosilicate waste
glass) are subjected to a 2-step heat treatment approach, whereby the raw
materials and flux mixture
is heated at temperatures up to 1180C and held at the melting temperature for
30 min to 2 hours,
then permitted to cool to between 500C and 600C and held for 30 to 60 min to
permit nucleation of
the glass melt, then the temperature is raised at 2 to l OC per minute to 800C
to 1000C and held for
30 min to 3 hours to permit crystallization of the melt to occur. Following
this, the crystallized melt
is permitted to cool to room temperature at 2 to l OC per minute.
In addition, the parent glass is first heated to a temperature between 850C
and 1000C at a
rate of between 2 and l OC per min, then sintered by holding for 30 min to 3
hours at a temperature
between 850C and 1000C to achieve maximum density of at least 2.3g/cm3.
A total of 94 different parent glasses were prepared from the same raw
materials and four
different fluxes, while a total of 282 different glass-ceramics were prepared
from the 94 parent glass
materials using three different heat treatment processes (petrurgic, 2-step
and sintering) for each
parent glass. The results are provided in Tables I through Table VIII.
Furthermore, the range of physical characteristics of the glasses and glass-
ceramics, which
were determined using pieces from the sample glasses and glass-ceramics and
accepted methods,
along with the chemical resistance displayed by glass-ceramics and glasses,
compared satisfactorily
with known commercial products.
Table B also shows that as a rule, a glass-ceramic displays a higher expansion
coefficient,
and greater hardness, strength and toughness values than a glass of
corresponding chemical
composition. In addition, the hardness and strength values of sintered glass-
ceramics display greater
hardness and strength values than the corresponding glasses and glass-ceramics
of similar
composition that have been subjected to the 2-step heat treatment process. It
has been concluded
that the increased strength and hardness values of the sintered samples is due
to the variance in the
heat treatment process.
The invention can be explained in detail below on the basis of Examples. The
Examples
illustrate how glass and glass-ceramics with different properties can be
obtained by altering the type
and amount of raw materials, flux and silica and changing the heat treatment
methods employed.
The data obtained show that the glasses and glass-ceramics produced according
to the invention
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exhibit very good strength, fracture toughness and hardness, acceptable
bending strength, moderate
Young's modulus and good chemical durability, all of which properties suggest
their use as ceramic
wall and floor tiles. Several glasses also exhibit various porosities, which
would make them useful
for such things as kiln furniture, honeycomb substrates for catalysts and heat
exchangers.
EXAMPLES
Examples 1 to 94
Table I -
A total of six different manganese crust tailings-based glasses, according to
the invention,
with the weight percentage compositions of raw materials, silica and flux
given in Table I were
prepared using the method of melting the raw materials with borax flux at
temperatures up to
1180C, cooling the melt at 2 to 15C per minute to 400 to 600C to anneal the
glass, holding the glass
at the annealing temperature for 30 to 120 minutes, then permitting the glass
to cool at 2 to 15C per
min to room temperature.
Glass Crust tailings Borax Silica
1 65 30 5
2 70 30 0
3 50 40 10
4 55 40 5
60 40 0
6 50 50 0
Glass-ceramics were prepared from parent glass materials as given in examples
1 to 6 (Table 1).
The heat treatment approach was varied (i.e. petrurgic, 2-step and sintering)
for each parent glass,
thus giving a total of 18 different glass-ceramics.
Table II -
A total of nine different manganese crust tailings-based glasses according to
the invention
with the weight percentage compositions given in Table II were prepared using
the method of
melting the raw materials with boric acid flux at temperatures up to 11 80C,
cooling the melt at 2 to
15C per minute to 400 to 600C to anneal the glass, hold the glass at the
annealing temperature for
30 to 120 minutes, then permitting the glass to cool at 2 to 15C per min to
room temperature.
Glass Crust tailings Boric acid Silica
7 75 20 5
8 80 20 0
9 50 30 20
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55 30 15
11 60 30 10
12 65 30 5
13 70 30 0
14 50 40 10
55 40 5
Glass-ceramics were prepared from parent glass materials as given in examples
7 to 15. The heat
treatment approach was varied (i.e. petrurgic, 2-step and sintering) for each
parent glass, thus giving
a total of 27 different glass-ceramics.
Table III -
A total of thirteen different manganese crust tailings-based glasses according
to the
invention with the weight percentage compositions given in Table III were
prepared using the
method of melting the raw materials with lithium tetraborate flux at
temperatures up to 11 80C,
cooling the melt at 2 to 15C per minute to 400 to 600C to anneal the glass,
holding the glass at the
annealing temperature for 30 to 120 minutes, then permitting the glass to cool
at 2 to 15C per min to
room temperature.
Glass Crust tailings Lithium tetraborate Silica
16 65 20 15
17 70 20 10
18 75 20 5
19 80 20 0
50 30 20
21 55 30 15
22 60 30 10
23 65 30 5
24 70 30 0
50 40 10
26 55 40 5
27 60 40 0
128 50 50 0
Glass-ceramics were prepared from parent glass materials as given in examples
16 to 28. The heat
treatment approach was varied (i.e. petrurgic, 2-step and sintering) for each
parent glass, thus giving
a total of 39 different glass-ceramics.
Table IV -
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A total of eight different manganese crust tailings-based glasses according to
the invention
with the weight percentage compositions given in Table IV were prepared using
the method of
melting the raw materials with borosilicate waste glass flux at temperatures
up to 11 80C, cooling
the melt at 2 to 15C per minute to 400 to 600C to anneal the glass, holding
the glass at the annealing
temperature for 30 to 120 minutes, then permitting the glass to cool at 2 to
15C per min to room
temperature.
Glass Crust tailings Borosilicate waste Silica
glass
29 75 20 5
30 80 20 0
31 50 30 20
32 55 30 15
33 60 30 10
34 65 30 5
35 50 40 10
36 55 40 5
Glass-ceramics were prepared from parent glass materials as given in examples
29 to 36. The heat
treatment approach was varied (i.e. petrurgic, 2-step and sintering) for each
parent glass, thus giving
a total of 24 different glass-ceramics. Details are provided in Table C,
regarding the tested
properties of these glass-ceramics.
Table V -
A total of sixteen different manganese nodules tailings-based glasses
according to the
invention with the weight percentage compositions given in Table V were
prepared using the
method of melting the raw materials with borax flux at temperatures up to
1150C, cooling the melt
at 2 to 15C per minute to 400 to 600C to anneal the glass, holding the glass
at the annealing
temperature for 30 to 120 minutes, then permitting the glass to cool at 2 to
15C per min to room
temperature.
Glass Nodules tailings Borax Silica
37 50 20 30
38 55 20 25
39 60 20 20
40 65 20 15
41 70 20 10
42 75 20 5
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CA 02664990 2009-04-29
43 80 20 0
44 50 30 20
45 55 30 15
46 60 30 10
47 65 30 5
48 70 30 0
49 50 40 10
50 55 40 5
51 60 40 0
52 50 50 0
Glass-ceramics were prepared from parent glass materials as given in examples
37 to 52. The heat
treatment approach was varied (i.e. petruric, 2-step and sintering) for each
parent glass, thus giving
a total of 48 different glass-ceramics.
Table VI -
A total of thirteen different manganese nodules tailings-based glasses
according to the
invention with the weight percentage compositions given in Table VI were
prepared using the
method of melting the raw materials with boric acid flux at temperatures up to
11 50C, cooling the
melt at 2 to 15C per minute to 400 to 600C to anneal the glass, holding the
glass at the annealing
temperature for 30 to 120 minutes, then permitting the glass to cool at 2 to
15C per min to room
temperature.
Glass Nodules tailings Boric acid Silica
53 65 20 15
54 70 20 10
55 75 20 5
56 80 20 0
57 50 30 20
58 55 30 15
59 60 30 10
60 65 30 5
61 70 30 0
62 50 40 10
63 55 40 5
64 60 40 0
65 50 50 0
Glass-ceramics were prepared from parent glass materials as given in examples
53 to 65. The heat
treatment approach was varied (i.e. petrurgic, 2-step and sintering) for each
parent glass, thus giving
a total of 39 different glass-ceramics..
CA 02664990 2009-04-29
Table VII -
A total of sixteen different manganese nodules tailings-based glasses
according to the
invention with the weight percentage compositions given in Table VII were
prepared using the
method of melting the raw materials with lithium tetraborate flux at
temperatures up to 1150C,
cooling the melt at 2 to 15C per minute to 400 to 600C to anneal the glass,
holding the glass at the
annealing temperature for 30 to 120 minutes, then permitting the glass to cool
at 2 to 15C per min to
room temperature.
Glass Nodules tailings Lithium tetraborate Silica
66 50 20 30
67 55 20 25
68 60 20 20
69 65 20 15
70 70 20 10
71 75 20 5
72 80 20 0
73 50 30 20
74 55 30 15
75 60 30 10
76 65 30 5
77 70 30 0
78 50 40 10
79 55 40 5
80 60 40 0
81 50 50 0
Glass-ceramics were prepared from parent glass materials as given in examples
66 to 81. The heat
treatment approach was varied (i.e. petrurgic, 2-step and sintering) for each
parent glass, thus giving
a total of 48 different glass-ceramics.
Table VIII -
A total of thirteen different manganese nodules tailings-based glasses
according to the
invention with the weight percentage compositions given in Table VIII were
prepared using the
method of melting the raw materials with borosilicate waste glass flux at
temperatures up to 1150C,
cooling the melt at 2 to 15C per minute to 400 to 600C to anneal the glass,
holding the glass at the
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annealing temperature for 30 to 120 minutes, then permitting the glass to cool
at 2 to 15C per min to
room temperature.
Glass Nodules tailings Borosilicate waste Silica
glass
82 65 20 15
83 70 20 10
84 75 20 5
85 80 20 0
86 50 30 20
87 55 30 15
88 60 30 10
89 65 30 5
90 70 30 0
91 50 40 10
92 55 40 5
93 60 40 0
94 50 50 0
Glass-ceramics were prepared from parent glass materials as given in examples
82 to 94. The heat
treatment approach was varied (i. e. petrurgic, 2-step and sintering) for each
parent glass, thus
giving a total of 39 different glass-ceramics.
A notable use of the invention is to make glass wool and glass-ceramic tiles
for use in construction
applications.
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