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F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
MOBILE GRINDING FACILITY
2. APPLICANT(S)
(a) NAME
(b) NATIONALITY
(c) ADDRESS
IMERYS MINERALS LIMITED
UNITED KINGDOM Company
PAR MOOR CENTRE,
PAR MOOR ROAD,
PAR CORNWALL PL24 2SQ
UNITED KINGDOM
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL
The following specification describes invention
COMPLETE (√)
The following specification particularly describes the invention
and the manner in which it is to be performed
4. DESCRIPTION (Description shall start from next page)
5. CLAIMS (not applicable for provisional specification. Claims should start with the preamble – “I/We claim”
on separate page)
6. DATE AND SIGNATURE ( to be given on the last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on the separate page)
Note:
* Repeat boxes in case of more than one entry
* To be signed by the applicant(s)or the authorized registered patent agent
* Name of the applicant should be given in full, family name in the beginning
* Complete address of the applicant should be given stating with postal index no. / code, state and country
* Strike out the column which is/are not applicable
*This Form is digitally signed.

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TECHNICAL FIELD
The present invention is directed to a mobile facility for producing an inorganic
particulate material, to a mobile facility for grinding a fibrous substrate comprising
cellulose, and to related methods of producing an inorganic particulate material and
ground fibrous substrate comprising cellulose.
BACKGROUND OF THE INVENTION
As the identification of mineral deposits in new and remote locations increases, there
is a need for processing facilities which can be put to use on such deposits quickly,
efficiently and in an environmentally less intrusive manner, particularly where the
quality and quantity of the mineral deposit is difficult to quantify and/or the mineral
deposit is situated in an environmentally sensitive location.
SUMMARY OF THE INVENTION
According to a first aspect, there is provide a mobile facility for producing an
inorganic particulate material comprising:
one or more grinders;
a feeder for providing feed material to the one or more grinders; and
auxiliary apparatus;
wherein the facility is configured or adapted to produce an inorganic particulate
material whereby the particle size of the feed material is reduced by a ratio of at least
about 10:1, or about 100:1, or about 1,000:1 to produce the inorganic particulate
material.
According to a second aspect, there is provided a method of relocating a mobile
facility for producing an inorganic particulate material, the method comprising:
at a first location, removing (e.g., dismantling) a previously installed mobile
facility according to the first or seventh aspect,
transporting the dismantled mobile facility to a second location, and
installing the mobile facility at the second location.
According to a third aspect, there is provided a method of installing a mobile facility
for producing an inorganic particulate material, the method comprising:
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transporting a mobile facility according to the first or seventh aspect to a
location, and
installing the mobile facility at the location.
According to a fourth aspect, there is provided a method of manufacturing an
inorganic particulate material, the method comprising grinding a feed material in a
mobile facility according to the first aspect to produce an inorganic particulate
material, whereby the particle size of the feed material is reduced by a ratio of at
least about 10:1.
According to a fifth aspect, there is provided a mobile facility for grinding a fibrous
substrate comprising cellulose comprising:
one or more grinders;
a feeder for providing feed material to the one or more grinders; and
wherein the facility is configured or adapted to grind a fibrous substrate comprising
cellulose.
According to a sixth aspect, there is provided a method of grinding a fibrous
substrate comprising cellulose, optionally in the absence of an inorganic particulate
material, the method comprising grinding a feed material comprising a fibrous
substrate comprising cellulose in a mobile facility according to the fifth aspect,
optionally wherein the feed material is ground to produce microfibrillated cellulose.
According to a seventh aspect, there is provided a mobile facility for producing an
inorganic particulate material comprising:
one or more reactors in a modular container for making an inorganic particulate
material, for example, precipitated calcium carbonate;
optionally one or more grinders for grinding starting material fed to the one or
more reactors and/or for grinding the inorganic material produced in the one or
more reactors;
a feeder for providing starting material to the one or more reactors and/or the
optional one or more grinders; and
auxiliary apparatus.
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According to an eighth aspect, there is provided a method of manufacturing an
inorganic particulate material, the method comprising making an inorganic particulate
material, for example, precipitated calcium carbonate, in a mobile facility according
to the seventh aspect.
DETAILED DESCRIPTON OF THE DESCRIPTION
By “mobile” it is meant that the facility is able to move or be moved easily in a
relatively short time frame and transportable between locations, and installable nonpermanently
enabling de-installation, relocation, re-installation and reuse. By “nonpermanently”
is meant that the facility can be disassembled and ready for relocation
to another site in no more than about a month or so (e.g., in less than about 50 days,
or less than about 40 days, or less than about calendar month, or less than about 4
weeks, or less than about 3 weeks, or less than about 2 weeks, or less than about 1
week).
In certain embodiments, the facility is modular. By “modular” it is meant that the
facility is composed of self-contained units or sections for easy construction or
flexible arrangement. The self-contained units or sections may be of a standardized
size and form. The self-contained units can be combined or interchanged with
others like it to construct or modify the mobile facility. The modular arrangement
also facilitates transportation between different (remote) locations, for example,
between a manufacturing site or sites at which modules are manufactured and a
production site at which the mobile is installed to produce the inorganic particulate
material, or between different production sites. The modular system can be
characterized by functional partitioning into discrete scalable, transportable, reusable
and replaceable modules.
The mobile and modular facility offers many benefits including reduction in cost,
flexibility in design, augmentation (e.g., retro-fit and expansion/addition of further
modules) and exclusion (including replacement or repair), quick installation, quick
deployment and quick removal and relocation. Environmental benefits include
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reduced energy consumption, reduced carbon foot-print including reduced CO2
emissions. For instance, the non-permanent installation reduces the need or even
eliminates the need for foundations (e.g., the mobile facility may in certain
embodiments may be foundationless). This means that the amount of foundation
materials such as concrete and the like required to install the facility may be
significantly reduce compared to installation of a larger, permanent facility.
The various modules may be containerized, for example, in a plurality of intermodal
freight containers. The intermodal container can be used across different modes of
transport – from ship to rail to truck. Intermodal containers exist in many types and a
number of standardized sizes. Commonly, the containers are either of 20 foot or 40
foot (6 or 12 m) standard length. The common heights are 8 feet 6 inches (2.6 m)
and 9 feet 6 inches (2.9 m), the latter being known as ‘High Cube’ (HC) containers.
In certain embodiments, one or more of the containers may be open-top and/or
open-side, enabling ready access to the apparatus contained therein.
Dimensions of common standardized types of container are given below in
Table 1.
In certain embodiments, the mobile facility comprises a plurality of intermodal units,
e.g., containers (e.g., stackable and/or modular containers) which are housed in or
on a vehicular conveying means, for example, a truck and the like, for example, the
flat-bed of a flat-bed truck. In such embodiments, the mobile facility may be
configured to produce the inorganic particulate material in one or more reactors, in
accordance with the seventh and/or eight aspects. In such embodiments, the mobile
facility may be configured to produce the inorganic particulate material in accordance
with the first and/or fourth aspects.
In certain embodiments, the mobile facility comprises a plurality of 20 and/or 40 foot
containers, each container comprising one or more parts of the mobile facility for
producing inorganic particulate material. The contents of the each module or
container may differ according to function. For example, one or more
modules/containers, or modular containers, may comprise apparatus designed for
delivery and initial preparation of the feed/starting material prior to grinding and/or
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reaction, another optionally modular container may comprise the one of more
grinders and/or one or more reactors, another may comprise post-grind classification
apparatus, and another may comprise storage apparatus. Other modules/containers
may contain support structures and/or pumping and/or piping. Yet further
modules/containers may operate as an office or control room, for example, an
electrical and power control room.
In addition to the one or more grinders and/or one or more reactors and feeder, the
mobile facility includes auxiliary apparatus suitable for the production of the inorganic
particulate material from the coarse feed material. The auxiliary apparatus may
comprises a variety of pre-grinding apparatus such as for example, feed hoppers
and crushers or other coarse sizing means as well as conveying means for
transporting the feed material from the hopper to the sizing means (e.g., a bucket
elevator) and to the feeder and then into the one or more grinders. The mobile
facility may additionally comprise support structures for the one or more grinders
and/or one or more reactors (and other auxiliary apparatus), which may additionally
comprise pumps and piping and space to drain, if necessary, media from the one or
more grinders. Post-grinding, the facility may comprise a classification system,
which may include classifiers, sizers and/or separators. Post-reaction, the facility
may comprise a classification system, which may include classifiers, sizers and/or
separators. For example, the mobile facility may comprise one or more screens,
such as vibrating screens, and a centrifuge system. The centrifuge may be
configured discharge to a storage tank. The mobile facility may comprise further
equipment such as fresh- and white-water tanks, a dispersant feed tank and biocide
feed tank. In certain embodiments, the mobile facility per se does not comprise such
tanks, but is configured to be connected thereto upon installation at the site of
production.
In certain embodiments, the auxiliary apparatus comprises one or more of: front-end
loader, feed hopper(s), surge hopper(s), bucket elevator(s), crusher(s), support
structure(s) for the one or more grinders, support structure(s) for the one or more
reactors, pump(s), drainage equipment, screen(s), classifier(s), chute(s), storage
tank(s), white water tank(s) and feed system, fresh water tank(s) and feed system,
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dispersant tank(s) and feed system, biocide tank(s) and feed system, control room
and office, and electrical and power control room.
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In certain embodiments, the mobile facility comprises at least:
a feed hopper in a first module/container;
a bucket elevator in a second module/container;
a surge hopper, crusher and the feeder for feed material in a third
module/container;
the one or more grinders in a fourth module/container;
support structure for the one or more grinders in a fifth module/container; one
or more vibrating screens in a sixth module/container;
a centrifuge feed tank in a seventh module/container;
a centrifuge in an eighth module/container; and
a storage tank for the inorganic particulate material in a ninth module/container.
The mobility and modularity of the mobile facility enables, at short notice, ready
installation and de-installation, and relocation of the mobile facility to a location
where a need arises. Thus, in one aspect there is provided a method for relocating a
mobile facility for producing an inorganic particulate material, the method comprising:
at a first location, removing (e.g., dismantling) a previously installed
mobile facility according to certain embodiments described herein,
transporting the dismantled mobile facility to a second location, and
installing the mobile facility at the second location.
In certain embodiments, removing the previously installed mobile facility ready for
transportation is conducted in a period of no more than about a calendar month, for
example, no more than about 4 weeks, or no more than about 3 weeks, or no more
than about 2 weeks, or no more than about 1 week.
The first location may be at least about 100 km from the second location, for
example, at least about 500 km, or at least about 1000 km, or at least about 1500
km, or at least about 2000 km, or at least about 2500 km from the second location.
Relocation may comprise transport by rail, road and/or sea. In certain embodiments,
relocation comprises transport by air.
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In certain embodiments, the mobile facility which is to be dismantled for relocation is
non-permanently installed at the first location.
In certain embodiments, for example, embodiments in which the mobile facility is
housed in or on a vehicular conveying means, the mobile facility may be configured
for permanent mobility. That is, it is intended to be moved from site to site on
demand and as desired without being permanently installed at a site.
The location or site of installation has civil, water and electrical power supplies in
situ.
The mobile facility is suitable for producing an inorganic particulate material which is
considerably finer than the feed material from which it is produced. The facility is
therefore configured or adapted to produce an inorganic particulate material whereby
the particle size of the feed material is reduced by a ratio of at least about 10:1.
Thus, by way of example, if the feed material has a particle size of about 1 mm and
the inorganic particulate material produced therefrom has a particle size of about 100
µm, then the particle size of the feed material is reduced by a ratio of about 10:1. By
way of another example, if the feed material has a particle size of about 2 mm and
the inorganic particulate material produced therefrom has a particle size of about 2
µm, then the particle size of the feed material is reduced by a ratio of about 1000:1.
By way of another example, if the feed material has a particle size of about 25 mm
and the inorganic particle produced therefrom has a particle size of about 1 µm, then
the particle size of the feed material is reduced by a ratio of about 25,000:1
The particle size of the feed material and inorganic particulate material may be
determined according to conventional methods known in the art which are suitable
for measuring the relatively coarse (i.e., the feed material) and fine (i.e., the
inorganic particulate material) materials used and produced in accordance with the
present invention.
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For example, for the relatively coarse feed material, particle size may be determined
by screening or sieving. Thus, in certain embodiments, the particle size of the feed
material is determined or obtained by screening or sieving using an appropriately
sized screen or sieve. In such embodiments, the particle size refers to the aperture
size of the screen or sieve, e.g., a feed material having a particle size of 5 mm is a
feed material which passes through a screen or sieve having 5 mm apertures.
For the relatively finer inorganic particulate material, particles size may determined
as the mean particle size, d50, which is the value of the particle e.s.d (equivalent
spherical diameter) at which there are 50 % by weight of the particles which have an
e.s.d less than that d50 value. In certain embodiments, the particle size, d50, of the
inorganic particulate is measured in a well known manner by sedimentation of the
particulate material in a fully dispersed condition in an aqueous medium using a
Sedigraph 5100 machine as supplied by Micromeritics Instruments Corporation,
Norcross, Georgia, USA (web-site: www.micromeritics.com), referred to herein as a
“Micromeritics Sedigraph 5100 unit”. Such a machine provides measurements and a
plot of the cumulative percentage by weight of particles having a size, referred to in
the art as the e.s.d, less than given e.s.d values.
In certain embodiments, to produce the inorganic particulate material the particle
size of the feed material is reduced by a ratio of at least about 50:1, or at least about
100:1, or at least about 250:1, or at least about 500:1, or at least about 750:1, or at
least about 1000:1, or at least about 1250:1, or at least about 1500:1, or at least
about 2000:1, or at least about 3000:1, or at least about 4000:1, or at least about
5000:1, or at least about 6000:1, or at least about 7000:1, or at least about 8000:1,
or at least about 9000:1, or at least about 10,000:1, or at least about 12,500:1, or at
least about 15:000:1, or at least about 17,500:1, or at least about 22,500:1, or at
least about 25;000:1. In certain embodiments, the particle size of the feed material
is reduced by a ratio of no more than about 100,000:1, for example, no more than
about 50,000:1. In such embodiments, the particle size of the feed material is at
least about 0.5 mm, or at least about 1 mm, or at least about 1.5 mm, or at least
about 2 mm, or at least about 2.5 mm, or at least about 3 mm, or at least about 3.5
mm, or at least about 4 mm, or at least about 4.5 mm, or at least about 5 mm. In
certain embodiments, the particle size of the feed material is at least about 10 mm,
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or at least about 25 mm, or at least about 50 mm, or at least about 100 mm, or at
least about 150 mm, or at least about 200 mm. In certain embodiments, the particle
size of the feed material is no greater than about 200 mm, for example, no greater
than about 150 mm, or no greater than about 100 mm, or no greater than about 50
mm, or no greater than about 10 mm, or no greater than about 8 mm, or no greater
than about 6 mm.
In certain embodiments, the particle size of the feed material fed to the first of the
one or more grinders is at least about 0.5 mm, or at least about 1 mm, or at least
about 1.5 mm, or at least about 2 mm, or at least about 2.5 mm, or at least about 3
mm, or at least about 3.5 mm, or at least about 4 mm, or at least about 4.5 mm, or at
least about 5 mm, or at least about 10 mm, or at least about 15 mm, or at least about
20 mm, or at least about 25 mm.
In certain embodiments, the particle size, d50, of the inorganic particulate material
which is produced from the feed material is no greater than about 250 µm, for
example, no greater than about 100 µm, or no greater than about 50 µm, or no
greater than about 25 µm, or no greater than about 10 µm, or no greater than about
5 µm, or no greater than about 2 µm, or no greater than about 1.5 µm, or no greater
than about 1 µm. In certain embodiments, the particle size, d50, of the inorganic
particulate material is at least about 0.1 µm, or at least about 0.25 µm, or at least
about 0.5 µm.
In certain embodiments, the particle size of the feed material is at least about 1 mm
and the particle size of the inorganic particulate material is no greater than about 5
µm, for example, no greater than about 2 µm.
In certain embodiments, the particle size of the feed material is at least about 2 mm
and the particle size of the inorganic particulate material is no greater than about 5
µm, for example, no greater than about 2 µm.
In certain embodiments, the particle size of the feed material is at least about 5 mm
and the particle size of the inorganic particulate material is no greater than about 5
µm, for example, no greater than about 2 µm.
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In certain embodiments, the particle size of the feed material is at least about 20 mm
and the particle size of the inorganic particulate material is no greater than about 2
µm, for example, the particle size of the feed material is at least about 25 mm and
the particle size of the inorganic particulate material is no greater than about 1 µm.
A described above, the facility, including the one or more grinders, is configured or
adapted to produce inorganic particulate material having the desired particle size,
d50, from a feed material having a particle size of at least about 0.5 mm, or at or at
least about 1 mm, or at least about 1.5 mm, or at least about 2 mm, or at least about
2.5 mm, or at least about 3 mm, or at least about 3.5 mm, or at least about 4 mm, or
at least about 4.5 mm, or at least about 5 mm.
The inorganic particulate material (and, thus, the feed material) may, for example, be
an alkaline earth metal carbonate or sulphate, such as calcium carbonate,
magnesium carbonate, dolomite, gypsum, a hydrous kandite clay such as kaolin,
halloysite or ball clay, an anhydrous (calcined) kandite clay such as metakaolin or
fully calcined kaolin, talc, mica, perlite or diatomaceous earth, or magnesium
hydroxide, or aluminium trihydrate, or combinations thereof.
In certain embodiments, the inorganic particulate material is calcium carbonate.
Hereafter, the invention may tend to be discussed in terms of calcium carbonate, and
in relation to aspects where the calcium carbonate is processed and/or treated. The
invention should not be construed as being limited to such embodiments.
The particulate calcium carbonate used in the present invention may be obtained
from a natural source by grinding. Ground calcium carbonate (GCC) is typically
obtained by crushing and then grinding a mineral source such as chalk, marble or
limestone. The feed material may be ground autogenously, i.e. by attrition between
the particles of the feed material themselves, or, alternatively, in the presence of a
particulate grinding medium comprising particles of a different material from the
calcium carbonate to be ground. These processes may be carried out with or
without the presence of a dispersant and biocides, which may be added at any stage
of the process.
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In certain embodiments, the feed material additionally comprises a fibrous substrate
comprising cellulose and, thus, the mobile facility including, for example, the one or
more grinders, is configured or adapted to grind a fibrous substrate comprising
cellulose. In certain embodiments, a fibrous substrate is added separately to at least
one of the one more grinders.
The fibrous substrate comprising cellulose may be in the form of a pulp (i.e., a
suspension of cellulose fibres in water), which may be prepared by any suitable
chemical or mechanical treatment, or combination thereof. For example, the pulp
may be a chemical pulp, or a chemithermomechanical pulp, or a mechanical pulp, or
a recycled pulp, or a papermill broke, or a papermill waste stream, or waste from a
papermill, or a combination thereof. The cellulose pulp may be beaten (for example
in a Valley beater) and/or otherwise refined (for example, processing in a conical or
plate refiner) to any predetermined freeness, reported in the art as Canadian
standard freeness (CSF) in cm3
. CSF means a value for the freeness or drainage
rate of pulp measured by the rate that a suspension of pulp may be drained. For
example, the cellulose pulp may have a Canadian standard freeness of about 10
cm3
or greater prior to being microfibrillated. The cellulose pulp may have a CSF of
about 700 cm3
or less, for example, equal to or less than about 650 cm3
, or equal to
or less than about 600 cm3
, or equal to or less than about 550 cm3
, or equal to or
less than about 500 cm3
, or equal to or less than about 450 cm3
, or equal to or less
than about 400 cm3
, or equal to or less than about 350 cm3
, or equal to or less than
about 300 cm3
, or equal to or less than about 250 cm3
, or equal to or less than about
200 cm3
, or equal to or less than about 150 cm3
, or equal to or less than about 100
cm3
, or equal to or less than about 50 cm3
. The cellulose pulp may then be
dewatered by methods well known in the art, for example, the pulp may be filtered
through a screen in order to obtain a wet sheet comprising at least about 10% solids,
for example at least about 15% solids, or at least about 20% solids, or at least about
30% solids, or at least about 40% solids. The pulp may be utilised in an unrefined
state, that is to say, without being beaten or dewatered, or otherwise refined.
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The fibrous substrate comprising cellulose may be added to the one or more
grinders in a dry state. For example, a dry paper broke may be added directly to the
one or more grinders. In certain embodiments, the aqueous environment in the
grinder will facilitate the formation of a pulp.
In certain embodiments, the fibrous substrate comprising cellulose is ground to
produce smaller fibrils. In certain embodiments, the fibrous substrate comprising
cellulose is microfibrillated during grinding, producing microfibrillated cellulose. By
microfibrillated is meant a process in which microfibrils of cellulose are liberated or
partially liberated as individual species or as smaller aggregates as compared to the
fibres of the pre-microfibrillated pulp. Typical cellulose fibres (i.e., premicrofribrillated
pulp) include larger aggregates of hundreds or thousands of
individual cellulose microfibrils.
The fibrous substrate comprising cellulose may be microfibrillated in the presence of
the inorganic particulate material to obtain microfibrillated cellulose having a d50
ranging from about 5 to µm about 500 µm, as measured by laser light scattering.
The fibrous substrate comprising cellulose may be microfibrillated in the presence of
the inorganic particulate material to obtain microfibrillated cellulose having a d50 of
equal to or less than about 400 µm, for example equal to or less than about 300 µm,
or equal to or less than about 200 µm, or equal to or less than about 150 µm, or
equal to or less than about 125 µm, or equal to or less than about 100 µm, or equal
to or less than about 90 µm, or equal to or less than about 80 µm, or equal to or less
than about 70 µm, or equal to or less than about 60 µm, or equal to or less than
about 50 µm, or equal to or less than about 40 µm, or equal to or less than about 30
µm, or equal to or less than about 20 µm, or equal to or less than about 10 µm.
The fibrous substrate comprising cellulose may be microfibrillated in the presence of
an inorganic particulate material to obtain microfibrillated cellulose having a modal
fibre particle size ranging from about 0.1-500 µm and a modal inorganic particulate
material particle size ranging from 0.25-20 µm. The fibrous substrate comprising
cellulose may be microfibrillated in the presence of an inorganic particulate material
to obtain microfibrillated cellulose having a modal fibre particle size of at least about
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0.5 µm, for example at least about 10 µm, or at least about 50 µm, or at least about
100 µm, or at least about 150 µm, or at least about 200 µm, or at least about 300
µm, or at least about 400 µm.
The fibrous substrate comprising cellulose may be microfibrillated in the presence of
an inorganic particulate material to obtain microfibrillated cellulose having a fibre
steepness equal to or greater than about 10, as measured by Malvern. Fibre
steepness (i.e., the steepness of the particle size distribution of the fibres) is
determined by the following formula:
Steepness = 100 x (d30/d70)
The microfibrillated cellulose may have a fibre steepness equal to or less than about
100. The microfibrillated cellulose may have a fibre steepness equal to or less than
about 75, or equal to or less than about 50, or equal to or less than about 40, or
equal to or less than about 30. The microfibrillated cellulose may have a fibre
steepness from about 20 to about 50, or from about 25 to about 40, or from about 25
to about 35, or from about 30 to about 40.
Unless otherwise stated, particle size properties of the microfibrillated cellulose
materials are as are as measured by the well known conventional method employed
in the art of laser light scattering, using a Malvern Mastersizer S machine as supplied
by Malvern Instruments Ltd (or by other methods which give essentially the same
result).
Details of the procedure used to characterise the particle size distributions of
mixtures of inorganic particle material and microfibrillated cellulose using a Malvern
Mastersizer S machine are provided in WO2010/131016.
In certain embodiments, at least one of the one or more grinders is a wet grinder
(i.e., the grinding process is a wet-grinding process). In certain embodiments, all of
the grinders are wet-grinders.
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In certain embodiments, at least one of the one or more grinders is an autogenous
grinder (i.e., the grinding process is an autogenous grinding process). In certain
embodiments, all of the grinders are autogenous grinders. In certain embodiments,
the autogenous grinder(s) is a tumbling mill.
In certain embodiments, at least one of the one or more grinders is a semiautogenous
grinder (i.e., the grinding process is a semi-autogenous grinding
process). In certain embodiments, all of the grinders are semi-autogenous grinders.
In certain embodiments, the mobile facility does not comprise a ball mill.
In certain embodiments, the mobile facility comprises a mill/grinder other than a ball
mill.
In certain embodiments, the mobile facility comprises a mill/grinder selected from a
tumbling mill, bead mill, disk mill, edge mill, hammer mill, Isa mill, jet mill, planetary
mill, stirred mill, vibratory mill, vertical shaft impactor mill, rod mill, autogenous mill,
SAG mill, pebble mill, sand mill and tower mill, and any combination thereof.
Wet grinding of calcium carbonate (and optional fibrous substrate comprising
cellulose) involves the formation of an aqueous suspension of the calcium carbonate
which may then be ground, optionally in the presence of a suitable dispersing agent.
Reference may be made to, for example, EP-A-614948 (the contents of which are
incorporated by reference in their entirety) for more information regarding the wet
grinding of calcium carbonate.
The grinding is suitably performed in a conventional manner. The grinding may be
an attrition grinding process in the presence of a particulate grinding medium, or may
be an autogenous grinding process, i.e., one in the absence of a grinding medium.
By grinding medium is meant a medium other than feed material.
The particulate grinding medium, when present, may be of a natural or a synthetic
material. The grinding medium may, for example, comprise balls, beads or pellets of
any hard mineral, ceramic or metallic material. Such materials may include, for
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example, alumina, zirconia, zirconium silicate, aluminium silicate or the mullite-rich
material which is produced by calcining kaolinitic clay at a temperature in the range
of from about 1300ºC to about 1800ºC. For example, in some embodiments a
ceramic grinding media is used. In certain embodiments, an at least 90 % pure
alumina grinding media is used. Alternatively, particles of natural sand of a suitable
particle size may be used.
Generally, the type of and particle size of grinding medium to be selected for use in
the invention may be dependent on the properties, such as, e.g., the particle size of,
and the chemical composition of, the feed suspension of material to be ground.
Preferably, the particulate grinding medium comprises particles having an average
diameter in the range of from about 0.1mm to about 6.0mm and, more preferably, in
the range of from about 0.2mm to about 4.0mm. The grinding medium (or media)
may be present in an amount up to about 70% by volume of the charge. The
grinding media may be present in amount of at least about 10% by volume of the
charge, for example, at least about 20 % by volume of the charge, or at least about
30% by volume of the charge, or at least about 40 % by volume of the charge, or at
least about 50% by volume of the charge, or at least about 60 % by volume of the
charge.
In certain embodiments, the facility and related methods are configured or adapted
for wet-grinding. Wet-grinding advantageously consumes lower power per tonne of
product, has higher capacity for per until grinder volume, enables the use of wet
screening and/or classification for close control of product particle size, eliminates
dust, and generally simplifies handling and transport aspects such as pumps and
pipes.
The grinding may be carried out in one or more stages. In certain embodiments, the
facility comprises only one grinder. In certain embodiments, the facility comprises a
plurality of grinders, for example, two grinders, or more than two grinders, for
example, three grinders, or four grinders, or five grinders. The plurality of grinders
may be operatively linked in series or parallel or a combination of series and parallel.
The output from and/or the input to one or more of the grinders in the facility may be
subjected to one or more screening steps and/or one or more classification steps.
18
The total energy expended in a grinding process may be apportioned equally across
each of the grinders in the facility. Alternatively, the energy input may vary between
some or all of the grinders in the facility.
In an embodiment the grinding is performed in a closed circuit. In another
embodiment, the grinding is performed in an open circuit. The grinding may be
performed in batch mode, for example, a re-circulating batch mode, or in continuous
mode.
The grinding circuit may include a pre-grinding step or steps in which a coarse feed
material is ground in a first grinder to a predetermined particle size distribution, after
which it passed to a different grinder until the desired particle size has been
obtained.
A suitable dispersing agent may be added to the suspension prior to grinding or
added sequentially during grinding or after grinding and dewatering. The dispersing
agent may be, for example, a water soluble condensed phosphate, polysilicic acid or
a salt thereof, or a polyelectrolyte, for example a water soluble salt of a poly(acrylic
acid) or of a poly(methacrylic acid) having a number average molecular weight not
greater than 80,000. The amount of the dispersing agent used would generally be in
the range of from 0.1 to 2.0% by weight, based on the weight of the dry feed
material. The suspension may suitably be ground at a temperature in the range of
from 4°C to 100°C.
The pH of the suspension of material to be ground may be about 7 or greater than
about 7 (i.e., basic), for example, the pH of the suspension may be about 8, or about
9, or about 10, or about 11. The pH of the suspension of material to be ground may
be less than about 7 (i.e., acidic), for example, the pH of the suspension may be
about 6, or about 5, or about 4, or about 3. The pH of the suspension of material to
be ground may be adjusted by addition of an appropriate amount of acid or base.
Suitable bases included alkali metal hydroxides, such as, for example NaOH. Other
suitable bases are sodium carbonate and ammonia. Suitable acids included
inorganic acids, such as hydrochloric and sulphuric acid, or organic acids. An
exemplary acid is orthophosphoric acid.
19
In some circumstances, minor additions of other minerals may be included, for
example, one or more of kaolin, calcined kaolin, wollastonite, bauxite, talc or mica,
could also be present.
When the feed material is obtained from naturally occurring sources, it may be that
some mineral impurities will contaminate the ground material. For example, naturally
occurring calcium carbonate can be present in association with other minerals.
Thus, in some embodiments, the feed material and, thus, the inorganic particulate
material, includes an amount of impurities. In general, however, the feed material
used and inorganic particulate produced will contain less than about 5% by weight,
preferably less than about 1% by weight, of other mineral impurities.
In certain embodiments, the feed material may be treated to reduce or remove
impurities, e.g., by flocculation, flotation, reductive bleaching or magnetic separation
techniques well known in the art. The auxiliary apparatus may include apparatus
suitable for flocculation, flotation, reductive bleaching or magnetic separation of the
feed material.
In alternative embodiments, there is provided a modular facility for producing an
inorganic particulate material comprising:
one or more reactors;
a feeder for providing reactants to the one or more reactors; and
auxiliary apparatus;
wherein the facility is configured or adapted to produce an inorganic particulate
material whereby the particle size of less than no greater than about 250 µm. For
example, the particle size is no greater than about 100 µm, or no greater than about
50 µm, or no greater than about 25 µm, or no greater than about 10 µm, or no
greater than about 5 µm, or no greater than about 2 µm, or no greater than about 1.5
µm, or no greater than about 1 µm. In certain embodiments, the particle size, d50, of
the inorganic particulate material is at least about 0.1 µm, or at least about 0.25 µm,
or at least about 0.5 µm.
20
The inorganic particulate produced by the modular facility may be precipitated
calcium carbonate (PCC). The PCC may be produced by any of the known methods
available in the art. TAPPI Monograph Series No 30, "Paper Coating Pigments",
pages 34-35, the contents of which are incorporated herein by reference, describes
the three main commercial processes for preparing precipitated calcium carbonate
which is suitable for use in preparing products for use in the paper industry, but may
also be used in connection with the embodiments of the present invention. In all
three processes, limestone is first calcined to produce quicklime, and the quicklime is
then slaked in water to yield calcium hydroxide or milk of lime. In the first process,
the milk of lime is directly carbonated with carbon dioxide gas. This process has the
advantage that no by-product is formed, and it is relatively easy to control the
properties and purity of the calcium carbonate product. In the second process, the
milk of lime is contacted with soda ash to produce, by double decomposition, a
precipitate of calcium carbonate and a solution of sodium hydroxide. The sodium
hydroxide should be substantially completely separated from the calcium carbonate
if this process is to be commercially attractive. In the third main commercial process,
the milk of lime is first contacted with ammonium chloride to give a calcium chloride
solution and ammonia gas. The calcium chloride solution is then contacted with soda
ash to produce, by double decomposition, precipitated calcium carbonate and a
solution of sodium chloride. Alternatively, PCC may be made by reacting gypsum
(calcium sulphate) with ammonium carbonate or ammonium bicarbonate.
Alternatively, PCC may be made by reacting calcium chloride with sodium carbonate
or ammonium carbonate. In certain embodiments, therefore, the mobile facility is
configured to produce wet or dry PCC by any one or more of the methods described
herein, and appropriate feeder and auxiliary apparatus selected depending on the
requirements of the process by which the PPC to be produced.
The process for making PCC results in very pure calcium carbonate crystals and
water. The crystals can be produced in a variety of different shapes and sizes,
depending on the specific reaction process that is used. The three main forms of
PCC crystals are aragonite, rhombohedral and scalenohedral, all of which are
suitable for use in embodiments of the present invention, including mixtures thereof.
21
In a further alternative embodiment, there is provided a mobile facility for grinding a
fibrous substrate comprising cellulose comprising:
one or more grinders;
a feeder for providing feed material to the one or more grinders; and
auxiliary apparatus.
In certain embodiments, the mobile facility is configured or adapted to produce
microfibrillated cellulose. The grinding may be conducted in the presence of a
grinding medium, and carried out in the absence of an inorganic particulate material.
The fibrous substrate comprising cellulose may be microfibrillated to obtain
microfibrillated cellulose having a d50 ranging from about 5 to µm about 500 µm, as
measured by laser light scattering. The fibrous substrate comprising cellulose may
be microfibrillated to obtain microfibrillated cellulose having a d50 of equal to or less
than about 400 µm, for example equal to or less than about 300 µm, or equal to or
less than about 200 µm, or equal to or less than about 150 µm, or equal to or less
than about 125 µm, or equal to or less than about 100 µm, or equal to or less than
about 90 µm, or equal to or less than about 80 µm, or equal to or less than about 70
µm, or equal to or less than about 60 µm, or equal to or less than about 50 µm, or
equal to or less than about 40 µm, or equal to or less than about 30 µm, or equal to
or less than about 20 µm, or equal to or less than about 10 µm.
The fibrous substrate comprising cellulose may be microfibrillated to obtain
microfibrillated cellulose having a modal fibre particle size ranging from about 0.1-
500 µm. The fibrous substrate comprising cellulose may be microfibrillated in the
presence to obtain microfibrillated cellulose having a modal fibre particle size of at
least about 0.5 µm, for example at least about 10 µm, or at least about 50 µm, or at
least about 100 µm, or at least about 150 µm, or at least about 200 µm, or at least
about 300 µm, or at least about 400 µm.
22
The fibrous substrate comprising cellulose may be microfibrillated to obtain
microfibrillated cellulose having a fibre steepness equal to or greater than about 10,
as measured by Malvern. Fibre steepness (i.e., the steepness of the particle size
distribution of the fibres) is determined by the following formula:
Steepness = 100 x (d30/d70)
The microfibrillated cellulose may have a fibre steepness equal to or less than about
100. The microfibrillated cellulose may have a fibre steepness equal to or less than
about 75, or equal to or less than about 50, or equal to or less than about 40, or
equal to or less than about 30. The microfibrillated cellulose may have a fibre
steepness from about 20 to about 50, or from about 25 to about 40, or from about 25
to about 35, or from about 30 to about 40.

23
We Claim:
1. A mobile facility for producing an inorganic particulate material comprising:
one or more grinders;
a feeder for providing feed material to the one or more grinders; and
auxiliary apparatus;
wherein the facility is configured or adapted to produce an inorganic particulate
material whereby the particle size of the feed material is reduced by a ratio of at
least about 10:1, or about 100:1, or about 1,000:1 to produce the inorganic
particulate material.
2. The mobile facility of claim 1, wherein the one or more grinders are wet
grinders.
3. The mobile facility of claim 1 or 2, wherein the one or more grinders are
autogenous grinders.
4. The mobile facility of any preceding claim, wherein the grinders are configured
or adapted to process a feed material having a particle size of at least about 1
mm, or at least about 5 mm.
5. The mobile facility of any preceding claim, wherein the inorganic particulate
material has a particle size, d50, of no greater than about 5 µm, or no greater
than about 2 µm.
6. The mobile facility of any preceding claim, wherein the facility is modular.
24
7. The mobile facility of claim 8, wherein modules are containerized, for example,
in a plurality of intermodal freight containers.
8. The mobile facility of any preceding claim, wherein the facility is
foundationless.
9. The mobile facility of any of claims 1-9, wherein the facility comprises a
plurality of grinders, for example, two grinders, or more than two grinders, for
example, three grinders, or four grinders, or five grinders.
10. The mobile facility of claim 11, wherein the plurality of grinders are operatively
linked in series, or parallel, or a combination of series and parallel.
11. The mobile facility of any preceding claim, wherein the facility is configured or
adapted to operate in: (i) an open circuit or a closed circuit; and/or (ii) batch
mode or continuous mode.
12. The mobile facility of any preceding claim, wherein the auxiliary apparatus
comprises one or more of: front-end loader, feed hopper(s), surge hopper(s),
bucket elevator(s), crusher(s), support structure(s) for the one or more
grinders, pump(s), drainage equipment, screen(s), classifier(s), chute(s),
storage tank(s), white water tank(s) and feed system, fresh water tank(s) and
feed system, dispersant tank(s) and feed system, biocide tank(s) and feed
system, control room and office, and electrical and power control room.
25
13. The mobile facility of any preceding claim, comprising at least:
a feed hopper in a first module/container;
a bucket elevator in a second module/container;
a surge hopper, crusher and the feeder for feed material in a third
module/container;
the one or more grinders in a fourth module/container;
support structure for the one or more grinders in a fifth module/container;
vibrating screen in a sixth module/container;
centrifuge feed tank in a seventh module/container;
a centrifuge in an eight module/container; and
a storage tank for the inorganic particulate material in a ninth
module/container.
14. The mobile facility of any preceding claim, wherein the facility is configured or
adapted to be commissioned on a site in no more than a calendar month, e.g.,
in no more than 31 days.
15. A method of relocating a mobile facility for producing an inorganic particulate
material, the method comprising:
at a first location, removing (e.g., dismantling) a previously installed
mobile facility according to any one of claims 1-14 or 26-34,
transporting the dismantled mobile facility to a second location, and
installing the mobile facility at the second location.
26
16. The method of claim 15, wherein dismantling the previously installed mobile
facility ready for transportation is conducted in a period of no more than about
2 weeks.
17. A method of installing a mobile facility for producing an inorganic particulate
material, the method comprising:
transporting a mobile facility according to any one of claims 1-14 or 26-34
to a location, and
installing the mobile facility at the location.
18. The method claim 17, wherein the mobile facility is installed within a calendar
month of commissioning.
19. The method of claim 17 or 18, wherein the mobile facility is non-permanently
installed.
20. The method of any one of claims 17-19, wherein the mobile facility is: (i)
installed using less concrete than would be required to install a non-mobile,
non-modular facility; or (ii) is foundationless.
21. A method of manufacturing an inorganic particulate material, the method
comprising grinding a feed material in a mobile facility according to any one of
claims 1-15 to produce an inorganic particulate material, whereby the particle
size of the feed material is reduced by a ratio of at least about 10:1.
27
22. The method of claim 21, wherein the feed material has a particle size of at
least about 1 mm, or at least about 5 mm.
23. The of claim 21 or 22, wherein the inorganic particulate material has a particle
size, d50, of no greater than about 5 µm, or no greater than about 2 µm.
24. The method of any one of claims 21-23, wherein the inorganic particulate
material is an alkaline earth metal carbonate or sulphate, such as calcium
carbonate, magnesium carbonate, dolomite, gypsum, a hydrous kandite clay
such as kaolin, halloysite or ball clay, an anhydrous (calcined) kandite clay
such as metakaolin or fully calcined kaolin, talc, mica, perlite or diatomaceous
earth, or magnesium hydroxide, or aluminium trihydrate, or combinations
thereof.
25. The method of claim 24, wherein the inorganic particulate material is calcium
carbonate.
26. A mobile facility for producing an inorganic particulate material comprising:
one or more reactors in a modular container for making an inorganic
particulate material, for example, precipitated calcium carbonate;
optionally one or more grinders for grinding starting material fed to the one
or more reactors and/or for grinding the inorganic material produced in the one
or more reactors;
a feeder for providing starting material to the one or more reactors and/or
the optional one or more grinders; and
auxiliary apparatus.
28
27. The mobile facility of claim 26, wherein the facility is modular.
28. The mobile facility of claim 27, wherein modules are containerized, for
example, in a plurality of intermodal freight containers.
29. The mobile facility of any one of claims 26-28, wherein the facility is
foundationless.
30. The mobile facility of any of claims 26-30, wherein the facility comprises a
plurality of reactors, for example, two reactors, or more than two reactors, for
example, three reactors, or four reactors, or five reactors.
31. The mobile facility of claim 30, wherein the plurality of reactors are operatively
linked in series, or parallel, or a combination of series and parallel.
32. The mobile facility of any one of claims 26-31, wherein the facility is configured
or adapted to operate in: (i) an open circuit or a closed circuit; and/or (ii) batch
mode or continuous mode.
33. The mobile facility of any one of claims 26-32, wherein the auxiliary apparatus
comprises one or more of: front-end loader, feed hopper(s), surge hopper(s),
bucket elevator(s), crusher(s), support structure(s) for the one or more
reactors, and/or, when present, one or more grinders, pump(s), drainage
equipment, screen(s), classifier(s), chute(s), storage tank(s), white water
tank(s) and feed system, fresh water tank(s) and feed system, dispersant
tank(s) and feed system, biocide tank(s) and feed system, control room and
office, and electrical and power control room.
29
34. The mobile facility according to any preceding claim, wherein the mobile facility
comprises a plurality of intermodal units, e.g., containers (e.g., stackable
and/or modular containers) which are housed in or on a vehicular conveying
means, for example, a truck and the like, for example, the flat-bed of a flat-bed
truck.
35. A method of manufacturing an inorganic particulate material, the method
comprising making an inorganic particulate material, for example, precipitated
calcium carbonate, in a mobile facility according any one of claims 26-34.
36. The method of claim 35, wherein the inorganic particulate material is
precipitated calcium carbonate.