Note: Descriptions are shown in the official language in which they were submitted.
CA 02794587 2012-11-05
A Composition and Method for Producing Ceramic Building Materials
by Using Alberta Oil Sands Tailings
Field of Invention
100011 The present invention relates to a composition and a method for
preparation of ceramic
materials from Alberta oil sands tailings, wastes of oil sands operations, and
a method for
production of ceramic building and/or construction materials such as tiles
(floor, wall and roof)
and bricks (curb, barrier, pavement and masonry) from the oil sands tailings
wastes.
Background
100021 Many compositions and methods have been disclosed to utilize industrial
wastes as
primary raw materials for producing useful ceramic building and/or
construction materials.
Industrial wastes are the by-products of construction, mining or
manufacturing, agricultural
and horticultural and other industrial processes. They possess both physical
and chemical
properties, which can interact with the natural or artificial ecosystems that
they occupy.
Tailings waste lagoons and dams represent some of the largest man-made
structures in the
world. The large quantities of water stored in the voids of these tailings
impoundments can
make them potentially unstable and a potential risk to underlying ground
water. Many tailings
disposal facilities contain material that undergoes extremely slow self-weight
consolidation.
Examples include the fine tailings produced in the Oil Sands industry, and the
waste products
from the phosphate mining industry. Social, legal and financial pressures are
being directed
towards the problems arising from industrial wastes. For example, in the
United Kingdom the
Special Waste Regulations (1996) SI 1996/972 has been replaced by the
Hazardous Wastes
CA 02794587 2012-11-05
Regulations in 2003/4 and the Landfill (England and Wales) Regulations (2002)
SI 2002/
1559 are enacted. These changes likely result in an increase in the cost of
disposal of
industrial wastes.
10003] Northern Alberta of Canada reserves 85% of the world's oil sand
deposits. According
to official statistics of Canada, the deposit of Alberta oil sand contributes
approximately 175
billion barrels of crude oil, 20% is suitable for large-scale surface mining.
The mined ore
typically consists of 68-83% sand, 3-16% clay, 4-5% water and 10-11% bitumen.
In mining
operations, it takes about two tonnes of oil sands and 2.2-5.0 barrels of
river water to produce
a barrel of synthetic crude oil (SCO) and 1.5-2.0 barrels of mature fine
tailing (MFT)
containing 30% solids and 70% water by weight, a by-product of mining
operations.
Currently, there are more than 800 million m3 tailings holding in more than
130 km2 of
tailings ponds in the Alberta oil sands region. The tailings inventory is
increasing at a rate of
50 million m3 per year. Based on a centrifuge simulation study, the tailings
in tailings ponds
need more than 130 years to settle by themselves, holding a significant amount
of water and
occupying a huge area of disturbed land. Surface oil sand companies are facing
three major
challenges: water use, tailings treatment and disturbed land reclamation. The
legislations of
Alberta require reclamation of both the land disturbed by oil sand mining
activities (472 km2)
and the land occupied by tailings ponds (130 km2) to self-sustaining
ecosystems. In February
2009, the Energy Resources Conservation Board of Alberta, the oil industry
governing body
of Alberta government, issued its Directive 074, Tailings Performance Criteria
and
Requirements for Oil Sands Mining Schemes. According to the Directive 074, oil
sands
mining companies are required to process 50% of their tailings by the year of
2013 and turn
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their processed tailings into tailings deposits with trafficable surfaces
within 5 years of their
disposals.
[0004] U.S. Pat. No. 3,870,535 disclosed a method of treating coal mining
waste to produce a
cementitious material, which is self-hardening at atmospheric pressure, and
may be used as
structural fill, road base material, or alternatively as an aggregate
consolidated barrier to
prevent penetrating percolation and resulting surface water contamination.
Detailed
information regarding the composition's density and plasticity is not
disclosed. However, due
to its cementitious nature, the well known disadvantages of the composition
associated with
cement based products are high porosity and structural instability, and
therefore limiting in
application and potential utility.
[0005] U.S. Pat. No. 5,286,427 disclosed a method of producing an autoclaved
aerated
cement building material (termed AAC) by a process that uses the available
silica sand and
other raw materials in mine tailings, in particular copper mine tailings. The
AAC as produced
and claimed is of limited utility because the composition lacks plasticity and
is therefore
incapable of efficient subsequent reformation. The disadvantages associated
with the AAC
include high porosity and structural instability as a result of temperature
and climate
fluctuations.
[0006] US Pat. 6,204,430 and US Pat. 6,004,069 disclosed methods for
stabilizing wastes,
preparing construction materials and stabilizing soils using compositions
including
hexametaphosphate, with or without other additives. The wastes are a variety
of materials
including solid and liquid-containing wastes, including for example, common
debris or
hazardous, radioactive or toxic waste. This method involves combining a waste
material with
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hexametaphosphate, and in some cases other additives. The resulting amended
waste may also
be compacted. Another method involves use of hexametaphosphate compositions to
prepare
construction materials. This method involves combining hexametaphosphate with
a starting
material such as soil, soil-containing compositions, mine tailings, mill
tailings and
combinations thereof. The resulting mixture is then compacted. The method
yields a solid
material in which the hexametaphosphate chemically and physically binds to
soil constituents.
[0007] US Pat. 5,375,777 disclosed a process for making a building material
with improved
acid and water resistance from waste material. There is provided a process for
preparing a
building material. In the first step of this process, a waste product is
ground so that
substantially all of its particles are a thickness of less about 0.5 inches.
In the second step of
the process, a resin precursor material and a hardener are mixed to form an
epoxy mortar. In
the third step of the process, the ground up waste material is mixed with the
epoxy mortar. In
the fourth step of the process, sand is mixed with the epoxy mortar/waste
mixture. In the fifth
step of the process entrained air is removed from the mix.
[0008] US Pat. App 10,587,554 disclosed a solid construction material and a
method of
preparing such a solid construction material, which is based upon a sludge or
tailing material,
such as a dredged material. In particular, the invention provides the
possibility to control
important parameters such as mechanical strength, bearing strength, stiffness
specific weight,
permeability, processibility and/or cost of a solid construction material
obtainable from a fluid
mixture.
[0009] US Pat. App 9,892,488 disclosed a method of making cement from tailings
or rock
fines containing silicate or siliceous compounds includes grinding the
tailings or rock fines to
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a size in the range of from about 250 to about 425 mesh to produce ground
pozzolan. The
ground pozzolan is mixed with Type 1 normal Portland cement or Type 3 high
early strength
Portland cement in a ratio of at least about 0.1:1 by weight to produce a
blended cement.
[0010] US Pat. 5,830,251 and US Pat. 5.935.885 disclosed a process of forming
ceramic tiles
having the appearance of tiles produced from clays. It provided for the use of
recycled glass
and fly ash as materials to be incorporated with other materials to produce
high quality, low
cost, high-value end products.
[0011] The composition of Canadian oil sand tailings are mainly coarse silica
sand and fine
clays in a typical sand-to-fine ratio of 4.25. The coarse and fine
classifications are defined by
the industry as its particle size being greater or less than 44 gm. They both
are good and
suitable to be used as main raw ceramic building and/or construction
materials. To
comprehensively use oil sands tailings wastes is a way that can turn Alberta
oil sand
operations into environmentally acceptable operations with much higher
economic benefit.
However, so far, there is no prior art describing such an application.
[0012] One object of this invention is to offer a compositions and methods
that use Canadian
oil sand tailings to produce ceramic building and/or construction materials.
Another object is
to provide a method of treating oil sand tailing by turning the wastes into
value added
products for North America market and make the oil sand an environmental
sustainable
industry.
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Summary of The Invention
[0013] The present invention provides a composition and methods for preparing
ceramic
materials and producing ceramic building and/or construction materials such as
tiles (floor,
wall and roof) and bricks (curb, barrier, pavement and masonry) by using
Alberta oil sands
tailings wastes.
Brief Description Of The Drawings
[0014] Fig. 1 is a schematic flow diagram of the method for preparation of
ceramic materials
from oil sand tailing wastes.
[0015] Fig. 2 is a tabular illustration of typical compositions of fine clays
(<45 gm) and
coarse sand (>45 gm) for ceramics.
[0016] Fig. 3 Solids and hydrocarbon content as a function of depth in the
Suncor Settling
Pond 3 (Redraw from data of Mikula etal.,1996)
[0017] Fig. 4 Solids particle size distribution as a function of depth in the
Suncor Settling
Pond 3 (Redraw from data of Mikula etal.,1996)
[0018] Fig. 5 is a tabular illustration of typical chemical compositions of
different size
fractions of oil sands tailings.
Detailed Description of Preferred Embodiments
[0019] One embedment of the present invention is described below with
reference to Fig. 1,
which is a schematic flow diagram of the method for preparation of ceramic
materials from oil
sand tailing wastes (1), which can be raw tailings discharged from a bitumen
extraction plant
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or mature fine tailing (MFT) dredged from a tailings pond. In the case of raw
tailings, received
from a bitumen extraction plant, typically containing 50% solids, 0.40-1.30%
residual
bitumen and balance water, the residual bitumen needs to be removed in a
bitumen removal
unit (2) before going to an iron removal unit (6), preferably the residual
bitumen is removed in
an integrated flotation unit disclosed in a previous application US
61/442,957. The integrated
flotation unit separates the tailings into three streams: bitumen froth (3),
fine clays (4) and
coarse sand (5). It is very important to remove residual bitumen from either
raw tailings or
MFT because the spaces occupied by the bitumen in tailings will be left as
void spaces after
the bitumen is burned during firing. Present firing technology allows for the
firing cycle in
traditional tile production to be less than 1 hour. The shortest firing times
of traditional clay
bodies are limited by the organic material present in the clay. A high carbon
level in the clay
can lead to "black core" in the final tile product. Black core occurs when the
center of the tile
body obtains a dark color due to the reducing effects of incompletely oxidized
carbon. This
effect is undesirable in the production of light colored and unglazed tiles.
Another problem
with high level of bitumen presence is that the sticky bitumen will reduce
efficiency of
magnetic iron removal (6) in the next process. The magnetic iron removal
process can be
skipped if the produced clays (8) are for colored ceramics or glazed ceramics.
Subject to
ceramic composition requirement for achieving different ceramic
characteristics, the produced
clays (8) can be further fractionated in a size fractionation unit (10) into
different size
fractions (11), which will be detailed later in this specification. The
separated coarse sand
passes a grinding and purification unit (7) for bringing particle size down to
less than 200 im
sand (8) ready for ceramics.
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[0020] The fine clays (4) and coarse sand (5) have their typical compositions
as shown in
Figure 2. The fine clays are high in desirable Si02 (65.90%), A1203 (22.75%)
and undesirable
Fe203 (4.10%) to be used as ceramic building/construction materials. While the
coarse sand
(5) contains very high Si02 (93.8%) and low A1203 (2.75%).
[0021] Fine clays have a function as a binder in ceramic production. Clays
have also a
function of improving, when making a formed body by means of a press,
formability of the
formed body. In addition, clays have a function of melting during firing to
fasten aggregates to
each other. Silica sand has a function as an aggregate, and a function of
minimizing the
variation in the volume of the formed body during firing. Iron oxide has a
function of keeping
the tone of color of the ceramic products. However, for white or light colored
ceramic
products, iron removal becomes necessary.
[0022] In the case of using mature fine tailings (MFT), holding in tailings
ponds and typically
containing 30% fine solids, 2-3% residue bitumen and balance water, as a
ceramic raw
material, the fine solids and residue bitumen contents vary vertically as
shown in Fig. 3, which
is an illustration of solids and hydrocarbon content variations as a function
of depth in the
Suncor Settling Pond 3 in 1996. It is also known that solids particle size
changes with depth in
a tailings pond. Fig. 4 is an illustration of solids particle size
distribution as a function of
depth in the Suncor Settling Pond 3 in 1996, showing that the larger the
particles the greater
depth they stayed in. Due to the fact that different sizes of solids particles
have different
chemical characteristics, it is necessary to dredge the MFT in a way best
suitable for different
ceramic compositions.
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[0023] With reference to Fig. 5, being a tabular illustration of typical
chemical components of
different size fractions, the finer the particles of a size fraction the lower
in its Si02 and
Fe203, and the higher in its A1203, meaning that same amount of MFT with
different size
fractions in a ceramic composition will result in ceramic products with
different quality and
characteristics. Predetermination of profiles of content and size of solids in
a tailings pond is
required before dredging MFT. The MFT can be then dredged at a certain depth
as required by
a ceramic composition so as to minimize cost for further grinding and particle
size screening.
[0024] Another embedment of the present invention is a composition in general
for ceramic
building and/or construction materials containing fine clays (from oil sand
tailings) 30-100%,
coarse sand (from oil sand tailings) 0-30%, Nail( feldspar 0-30% and ball clay
0-25%, all by
weight of dry bases, where the main chemical components of the composition are
shown in a
table below:
Si02 A1203 Fe203 K20 Na20 P CaO
Fine clays ( 5.0%) ( 5.0%) ( 2.5%) ( 0.5%) ( 0.5%) (
0.3%)
(from oil sand tailings)
65.9% 23.0% 4.1% 2.8% 0.4% 0.5%
Si02 A1203 Fe203 K20 Na20 Ca0
Coarse sand ( 5.0%) ( 2.0%) ( 0.3%) ( 0.3%) ( 0.1%)
( 0.1%)
(from oil sand tailings)
93.8% 2.8% 0.3% 0.5% 0.1% 0.1%
Si02 A1203 Fe203 K20 Na20 CaO
K=Na -Feldspar ( 3%) ( 3%) ( 1%) ( 5%) ( 2%) (
2%)
68% 19% 1% 10% 3% 2%
Si02 A1203 Fe203 K20 Na20 Ca0
Ball clay ( 3%) ( 3%) ( 1%) ( 1%) ( 1%) ( 1%)
55% 30% 1% 1% 1% 1%
The fine clays in the ceramic composition can be either a fractionated size
fraction of raw
tailings discharged from a bitumen extraction plant or a fractionated size
fraction of MFT
from which the bitumen and iron are removed. The size fractionation of MFT can
be carried
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out either by dredging the MFT from a certain vertical location in a tailings
pond where a
desired size fraction of fine solids present or by dredging the MFT from
different vertical
locations and forming a mixture of dredged material then using the size
fractionation unit (10)
to obtain different size fractions. In both cases, the residual bitumen in the
fine clays must be
removed before or during the size fractionation. The leftover bitumen level in
the fine clays
should be controlled less than 5% by weight of dry fine clay.
[0025] Another embedment of the present invention provides a method of
producing the
ceramic building and/or construction tiles (floor, wall and roof) and bricks
(curb, barrier,
pavement and masonry). Said method comprises the steps of
¨ removing residual bitumen and iron from oil sand tailings as shown in
Fig.1 then
followed by flocculation and sedimentation,
¨ preparing the composition according to required dosages of tailings and
other
materials,
¨ mixing, drum milling, maturing and spraying or flash drying the mixture
to produce a
body material or dust pressing powder for ceramic tiles,
¨ alternatively, mixing, pan milling and dewatering the mixture in a filter
press or a
rotational filter to produce extrusion paste to a water content of between 20
and 25 %
for bricks,
¨ shaping the body material to green-ware by pressing the dust pressing
powder for
ceramic tiles or by extruding the extrusion paste for bricks,
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¨ drying the green-ware in a tunnel dryer, roller dryer or vertical dryer,
¨ firing the dried green-ware in a roller hearth kiln, tunnel kiln or
periodically operated
kiln.
[0026] Preferably, the diameters of particles of the body material is
controlled less than 200
gm. Firing temperatures for different ceramic products should be controlled
between 800-
1,300 C. The green-ware can also be fired after glazing. All the processes
used here,
including iron removal, maturing, milling, shaping, drying and firing, are
conventional in the
industry.
[0027] The present invention utilizes mature technologies and waste materials
to produce
value added porcelains, chinaware and earthenware with a very low rate of
defective products.
In addition, the present invention provides a cost effective way to achieve
economic and
environmental benefits.
[0028] The present invention will now be described with reference to the
following, but not
limited to, examples:
Fine clays coarse sand Na.K-
ingredient Ball clay
(from oil sand tailings) (from oil sand tailings) Feldspar
Example 1 69% 0% 17% 15%
Example 2 59% 0% 21% 20%
Example 3 90% 0% 0% 10%
Example 4 75% 0% 15% 10%
Example 5 85% 15% 0% 0%
Example 6 100% 0% 0% 0%
Example 7 38% 30% 12% 20%
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