US20240043326A1 - Production of aggregates - Google Patents
Production of aggregates Download PDFInfo
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- US20240043326A1 US20240043326A1 US18/486,933 US202318486933A US2024043326A1 US 20240043326 A1 US20240043326 A1 US 20240043326A1 US 202318486933 A US202318486933 A US 202318486933A US 2024043326 A1 US2024043326 A1 US 2024043326A1
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- carbonatable
- waste
- blended
- process according
- damp
- Prior art date
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- 238000004519 manufacturing process Methods 0.000 title description 10
- 239000002699 waste material Substances 0.000 claims abstract description 167
- 239000000203 mixture Substances 0.000 claims abstract description 73
- 238000000034 method Methods 0.000 claims abstract description 57
- 239000011230 binding agent Substances 0.000 claims abstract description 53
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 34
- 238000002156 mixing Methods 0.000 claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 17
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 17
- 239000010881 fly ash Substances 0.000 claims abstract description 16
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 9
- 239000002893 slag Substances 0.000 claims abstract description 9
- 239000010959 steel Substances 0.000 claims abstract description 9
- 238000002360 preparation method Methods 0.000 claims abstract description 6
- 239000011398 Portland cement Substances 0.000 claims description 45
- 238000003915 air pollution Methods 0.000 claims description 37
- 239000004568 cement Substances 0.000 claims description 24
- 239000000428 dust Substances 0.000 claims description 22
- 239000002028 Biomass Substances 0.000 claims description 21
- 239000002956 ash Substances 0.000 claims description 20
- 239000002245 particle Substances 0.000 claims description 16
- 238000007873 sieving Methods 0.000 claims description 10
- 238000003825 pressing Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 abstract description 46
- 239000008188 pellet Substances 0.000 description 34
- 239000004677 Nylon Substances 0.000 description 10
- 229920001778 nylon Polymers 0.000 description 10
- 239000011347 resin Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 238000001914 filtration Methods 0.000 description 4
- 239000008367 deionised water Substances 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 230000003116 impacting effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/06—Combustion residues, e.g. purification products of smoke, fumes or exhaust gases
- C04B18/08—Flue dust, i.e. fly ash
- C04B18/085—Pelletizing
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/02—Agglomerated materials, e.g. artificial aggregates
- C04B18/021—Agglomerated materials, e.g. artificial aggregates agglomerated by a mineral binder, e.g. cement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
- B09B3/20—Agglomeration, binding or encapsulation of solid waste
- B09B3/25—Agglomeration, binding or encapsulation of solid waste using mineral binders or matrix
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/0481—Other specific industrial waste materials not provided for elsewhere in C04B18/00
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/06—Combustion residues, e.g. purification products of smoke, fumes or exhaust gases
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/14—Waste materials; Refuse from metallurgical processes
- C04B18/141—Slags
- C04B18/142—Steelmaking slags, converter slags
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/02—Treatment
- C04B20/023—Chemical treatment
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B2101/00—Type of solid waste
- B09B2101/30—Incineration ashes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Definitions
- the present invention relates to the production of aggregates comprising air pollution control residue with a carbonatable substance.
- the present invention also relates to the production of aggregates comprising portland cement and air pollution control residue, cement bypass dust or biomass ash.
- the present invention also relates to the production of aggregates comprising two or more carbonatable wastes.
- Primary aggregates for use in concrete mixtures are produced from naturally formed rocks, stones and gravels.
- Embodiments of the present invention seek to provide an improved process for the preparation of aggregates, in particular secondary aggregates.
- the first aspect of the present invention provides a process for the production of secondary aggregates comprising a combination of air pollution control residue, which is typically recovered from incineration of municipal waste, and a carbonatable (i.e. carbon dioxide reactive) substance.
- a carbonatable (i.e. carbon dioxide reactive) substance Such a combination provides a significant increase in the rate of hardening of the aggregate during carbonation, which enables the aggregate to be formed much more quickly than conventional secondary aggregates.
- the carbonatable substance may be cement bypass dust, biomass ash or ordinary portland cement.
- the process may further comprise the step of initially sieving or filtering or separating the carbonatable substance and/or the air pollution control residue before they are blended together.
- the carbonatable substance and/or the air pollution control residue may be initially sieved, filtered or separated to obtain an average particle size of less than around 0.1 mm, in particular around 0.05 mm to 0.1 mm.
- the air pollution control residue and carbonatable substance may be blended in a vessel.
- the vessel may be a beaker.
- the vessel or beaker may have a volume of around 25 ml.
- the air pollution control residue and carbonatable substance may be blended by hand or may be blended by a machine such as a planetary mixer.
- the weight ratio between the air pollution control residue and the carbonatable substance may be approximately 1:2 or approximately 2:1.
- the weight ratio may be approximately 1:1.5 or approximately 1.5:1. More preferably, the weight ratio may be approximately 1:1.
- the blended air pollution control residue and carbonatable substance may be mixed with around 15-30% w/w of water, alternatively around 15-25% w/w of water, or alternatively around 20-30% w/w of water, or around 25% w/w of water, to form the damp blended air pollution control residue and carbonatable substance mixture.
- the process may further comprise the step of mixing the damp blended air pollution control residue and carbonatable substance mixture after its mixing with water.
- the damp blended air pollution control residue and carbonatable substance mixture may be mixed by hand or may be mixed by a machine such as a planetary mixer. In this way, a second stage of mixing may ensure that water is spread evenly throughout the mixture.
- the process may further comprise the step of sieving the damp blended air pollution control residue and carbonatable substance mixture.
- the damp blended air pollution control residue and carbonatable substance mixture may be sieved to obtain an average particle size of around 0.05 mm to 0.15 mm, in particular an average particle size of around 0.1 mm or less than 0.1 mm.
- the second aspect of the present invention provides a process for the production of secondary aggregates comprising a combination of portland cement and either air pollution control residue, cement bypass dust or biomass ash, which are carbonatable (i.e. carbon dioxide reactive) substances.
- a combination provides a significant increase in the rate of hardening of the aggregate during carbonation, which enables the aggregate to be formed much more quickly than conventional secondary aggregates.
- the process may further comprise the step of initially sieving or filtering or separating the carbonatable substance and/or the portland cement before they are blended together.
- the carbonatable substance and/or the portland cement may be initially sieved, filtered or separated to obtain an average particle size of less than around 0.1 mm, in particular around 0.05 mm to 0.1 mm.
- the portland cement and carbonatable substance may be blended in a vessel.
- the vessel may be a beaker.
- the vessel or beaker may have a volume of around 25 ml.
- the air pollution control residue and carbonatable substance may be blended by hand or may be blended by a machine such as a planetary mixer.
- the weight ratio between the portland cement and the carbonatable substance may be approximately 1:2 or approximately 2:1.
- the weight ratio may be approximately 1:1.5 or approximately 1.5:1. More preferably, the weight ratio may be approximately 1:1.
- the blended portland cement and carbonatable substance may be mixed with around 25% w/w of water to form the damp blended portland cement and carbonatable substance mixture.
- the process may further comprise the step of mixing the damp blended portland cement and carbonatable substance mixture after its mixing with water.
- the damp blended portland cement and carbonatable substance mixture may be mixed by hand or may be mixed by a machine such as a planetary mixer. In this way, a second stage of mixing may ensure that water is spread evenly throughout the mixture.
- the process may further comprise the step of sieving the damp blended portland cement and carbonatable substance mixture.
- the damp blended portland cement and carbonatable substance mixture may be sieved to obtain an average particle size of around 0.05 mm to 0.15 mm, in particular an average particle size of around 0.1 mm or less than 0.1 mm.
- the third aspect of the present invention provides a process for the production of secondary aggregates comprising a combination of at least two different carbonatable (i.e. carbon dioxide reactive) wastes.
- a combination of carbonatable wastes provides a significant increase in the rate of hardening of the aggregate during carbonation, which enables the aggregate to be formed much more quickly than conventional secondary aggregates.
- the first carbonatable waste may be air pollution control residue cement bypass dust, biomass ash or ordinary portland cement.
- the ordinary portland cement may be out-dated ordinary portland cement.
- the second carbonatable waste may be air pollution control residue cement bypass dust, biomass ash or ordinary portland cement.
- the ordinary portland cement may be out-dated ordinary portland cement.
- the process may further comprise the step of initially sieving or filtering or separating the first carbonatable waste and/or the second carbonatable waste before they are blended together.
- the first carbonatable waste and/or the second carbonatable waste may be initially sieved, filtered or separated to obtain an average particle size of less than around 0.1 mm, in particular around 0.05 mm to 0.1 mm.
- the process may further comprise the step of mixing the blended carbonatable waste with a carbonatable binder.
- the carbonatable binder may be cement kiln dust or ordinary portland cement.
- the process may further comprise the step of initially sieving or filtering or separating the carbonatable binder before blending with the first and second carbonatable wastes.
- the carbonatable binder may be sieved or filtered or separated to obtain a carbonatable binder having an average particle size of less than around in particular around 0.05 mm to 0.1 mm.
- the first carbonatable waste may be steel slag or pulverised fuel ash and/or the second carbonatable waste may be steel slag or pulverised fuel ash.
- the blended carbonatable waste may be blended in a vessel.
- the vessel may be a beaker.
- the vessel or beaker may have a volume of around 25 ml.
- the carbonatable wastes may be blended by hand or may be blended by a machine such as a planetary mixer.
- the weight ratio between the first carbonatable waste and the second carbonatable waste may be approximately 1:2 or approximately 2:1.
- the weight ratio may be approximately 1:1.5 or approximately 1.5:1. More preferably, the weight ratio may be approximately 1:1.
- the weight ratio between the first carbonatable waste, second carbonatable waste and carbonatable binder may be approximately 1:2:2 or approximately 2:1:2.
- the weight ratio may be approximately 1:1.5:2 or approximately 1.5:1:2. More preferably, the weight ratio may be approximately 1:1:2.
- the process may further comprise a step of mixing the blended carbonatable waste with a third carbonatable waste.
- the third carbonatable waste may be pulverised fuel ash or steel slag.
- the blended carbonatable waste may be mixed with around 25% w/w of water to form the damp blended carbonatable waste mixture.
- around 2.5 grams of water may be used.
- the water may be deionised water.
- the process may further comprise the step of mixing the damp blended carbonatable waste mixture after its mixing with water.
- the damp blended carbonatable waste mixture may be mixed by hand or may be mixed by a machine such as a planetary mixer. In this way, a second stage of mixing may ensure that water is spread evenly throughout the mixture.
- the process may further comprise the step of sieving the damp blended carbonatable waste mixture.
- the damp blended carbonatable waste may be sieved to obtain an average particle size of around 0.05 mm to 0.15 mm, in particular an average particle size of around 0.1 mm or less than 0.1 mm.
- the process of the first, second and/or third aspect of the invention may further comprise a step of pressing the damp blended air pollution control residue and carbonatable substance mixture or damp blended portland cement and carbonatable substance mixture or carbonatable waste mixture into a form or shape that resembles the shape of aggregate used in concrete.
- the damp blended mixture may be pressed into pellet form.
- the pressing step may occur before the carbonation step.
- This pressing step may occur after the blending step.
- the pellet form may be substantially cylindrical or substantially spherical.
- the mixture may be pressed into a pellet form or shape by using a pellet press. In this way, the mixture is pressed into its final shape before carbonation, whilst it is still mouldable.
- the process of the first, second and/or third aspect of the invention may comprise a step of tumbling the damp blended air pollution control residue and carbonatable substance mixture or damp blended portland cement and carbonatable substance mixture or damp blended carbonatable waste mixture.
- a tumbling process which may be employed is described in WO 2007/096671 A1. The tumbling may take place in the presence of carbon dioxide so that the carbonation step and the tumbling step take place concurrently.
- the damp blended mixture may be extruded.
- An extrusion process applying a force of between 50-100 N, alternatively less than 50 N, or alternatively more than 100 N, may be used.
- the pellet press may comprise a split mould.
- the split mould may be manufactured from nylon.
- the split mould may be around 30 mm ⁇ 10 mm.
- the split mould may have an aperture of around 8 mm for enabling removal of the pressed pellets.
- the pellet press may comprise a plunger.
- the plunger may be manufactured from cast resin.
- the plunger may be around 32 mm ⁇ 7.5 mm.
- the pellet press may comprise a retaining collar.
- the retaining collar may be reinforced.
- the retaining collar may be manufactured from nylon.
- the retaining collar may be around 230 mm ⁇ 160 mm.
- the retaining collar may have an aperture of around 100 mm.
- a force of around 50-150 N may be used to cast each pellet in the pellet press.
- a force of around 100 N may be used to cast each pellet in the pellet press.
- Each pellet of the damp carbonatable waste mixture may be formed from a mixture of approximately 2.5 grams of a first carbonatable waste, approximately 2.5 grams of a second carbonatable waste and approximately 5 grams of a carbonatable binder.
- each pellet may be formed from a mixture of approximately 5 grams of a first carbonatable waste and approximately 5 grams of a second carbonatable waste.
- each pellet may be formed from approximately 10 grams of dry material.
- the damp blended air pollution control residue and carbonatable substance mixture or damp blended portland cement and carbonatable substance mixture or carbonatable waste mixture may be carbonated in a carbon dioxide-rich gaseous environment. That is, the carbonation may be carried out in an atmosphere that has a carbon dioxide content greater than that of natural air. For example, the carbonation may be carried out in an atmosphere containing at least 50%, 60%, 70% or 80% carbon dioxide by volume. Preferably, the atmosphere may consist mostly of carbon dioxide, for example 90%, 85% or 99% by volume.
- the carbonation may take place in a carbonation chamber.
- the carbonation chamber may be fully or partially enclosed, for example the carbonation chamber may be a pan pelletiser.
- the carbonation chamber may have a volume of approximately 5 litres.
- the pressure in the carbonation chamber may be atmospheric pressure.
- the pressure in the carbonation chamber may be slightly above atmospheric pressure.
- the pressure in the carbonation chamber may be around 2 bar. This ensures that sufficient carbon dioxide is available to maximise or complete carbonation, without unduly impacting on strength development.
- the blended mixtures of the first, second and/or third aspects of the invention may comprise any number of additional carbonatable substances or wastes blended into the mixture.
- a third carbonatable substance or waste may be included in the blended mixture.
- the third carbonatable substance or waste may be steel slag or pulverised fuel ash.
- the third carbonatable substance or waste may be air pollution control residue, cement bypass dust or biomass ash.
- FIG. 1 is a schematic block diagram of a process according to an embodiment of the present invention
- FIG. 2 is a graph showing the strength of carbonatable wastes and combinations of carbonatable wastes produced by the process shown in FIG. 1 , with a carbonation time of 10 minutes;
- FIG. 3 is a graph showing the strength of carbonatable wastes and combinations of carbonatable wastes produced by the process shown in FIG. 1 , with a carbonation time of 20 minutes;
- FIG. 4 is a table showing the sources of various carbonatable wastes that are described herein;
- FIG. 5 is a table showing the % weight compositions of various carbonatable wastes that are described herein.
- FIG. 6 is a table showing the strength of pellets of individual carbonatable wastes produced by the process shown in FIG. 1 , with no second carbonatable waste and no carbonatable binder, with a carbonation time of 10 minutes;
- FIG. 7 is a table showing the strength of pellets of individual carbonatable wastes produced by the process shown in FIG. 1 , with no second carbonatable waste and no carbonatable binder, with a carbonation time of 20 minutes.
- a first carbonatable waste 1 and a second carbonatable waste 2 are initially selected.
- the first carbonatable waste 1 is cement bypass dust from cement production in the Midlands, UK
- the second carbonatable waste is biomass ash from biomass power generation in Picardie, France.
- the sources of the first and second carbonatable wastes 1 , 2 are shown in FIG. 4 .
- the compositions of the first and second carbonatable wastes 1 , 2 are shown in FIG. 5 .
- a carbonatable binder 3 is then selected.
- the carbonatable binder is ordinary portland cement (52.5 N), supplied by Cemex (RTM) Ltd.
- the composition of the carbonatable binder 3 is shown in FIG. 4 .
- step 104 approximately 2.5 grams of the first carbonatable waste 1 is sieved to obtain a particle size of less than 0.1 mm.
- step 105 approximately 2.5 grams of the second carbonatable waste 2 is sieved to obtain a particle size of less than 0.1 mm.
- step 106 approximately 5 grams of the carbonatable binder is sieved to obtain a particle size of less than 0.1mm.
- the sieved first carbonatable waste 1 , second carbonatable waste 2 and carbonatable binder 3 are combined into a 25 ml beaker and the mixture is thoroughly blended by hand to ensure homogeneity.
- the dry mixture thus weighs 10 grams.
- the blended carbonatable wastes 1 , 2 and carbonatable binder 3 mixture is wetted with 2.5 grams (25% w/w) of deionised water using a dropping pipette.
- the damp blended carbonatable wastes 1 , 2 and carbonatable binder 3 mixture is hand mixed for a second time to ensure that the water in the mixture is evenly distributed.
- the mixture is then sieved to ensure a particle size of less than 0.1 mm.
- the damp blended carbonatable wastes 1 , 2 and carbonatable binder 3 mixture is pressed into pellet form using a customised pellet press.
- the pellet press comprises a 30 mm ⁇ 10 mm nylon split mould with an 8 mm aperture to enable removal of pressed samples; a 32 mm ⁇ 7.5 mm cast resin plunger and a 230 mm ⁇ 160 mm reinforced nylon retaining collar with an aperture of 100 mm.
- the nylon split mould is inserted into the reinforced nylon retaining collar and placed onto a clean stainless steel dish.
- the damp mixture of blended carbonatable wastes 1 , 2 and a carbonatable binder 3 is carefully placed into the nylon split mould and the cast resin plunger is readied into position.
- a load of approximately 100 N is applied to the resin plunger to cast the pellet, measured by a Mecmesin (RTM) BFG500N force gauge, to an accuracy of ⁇ 0.1 N.
- the resin plunger is then removed carefully by hand and the nylon mould is removed from the reinforced nylon retaining collar.
- the nylon mould is split open using a spatula so that the pressed pellet can be removed for the mould.
- Five cylindrical pellets are typically produced for each mixture of blended carbonatable wastes 1 , 2 and carbonatable binder 3 .
- the pellets of blended carbonatable wastes 1 , 2 and carbonatable binder 3 are transferred to a five litre carbonation chamber containing carbon dioxide, where they begin to carbonate and harden/set.
- the chamber operates at a pressure of 2 bar, which is slightly above atmospheric pressure to ensure that a sufficient supply of carbon dioxide is available for carbonation of the pellets, but is not so high as to unduly impact on strength development.
- each pellet is removed from the chamber.
- the dimensions of each pellet are measured using a Mitutoyo (RTM) CD-6 CP measuring callipers, to an accuracy of ⁇ 0.01 mm.
- RTM Mitutoyo
- Each pellet has a diameter of approximately 7.7 mm and thus a radius of approximately 3.85 mm.
- the length ratio of each pellet is around 1.0 and thus the length of each pellet is around 7.7 mm.
- Each pellet is then destructively tested to determine its compressive strength.
- Each pellet is placed beneath a force gauge and load is applied to the force gauge until the pellet fails under compression.
- a Mecmesin (RTM) BFG500N force gauge was used, to an accuracy of ⁇ 0.1 N.
- FIG. 4 shows the sources of the carbonatable wastes discussed below and FIG. 5 shows the compositions of the carbonatable wastes shown in FIG. 4 .
- the compressive strength in Newtons of each sample was determined by using a Mecmesin (RTM) BFG500N force gauge in the manner as described in the Detailed Description of the Invention.
- the strength in MPa was determined by the following formula:
- FIGS. 6 and 7 show the average strength in MPa of five samples of each individual carbonatable waste. These reference samples were all prepared using the process described above in the Detailed Description of the Invention, except that there no second carbonatable waste and no carbonatable binder were added to the blend.
- FIGS. 2 and 3 show the average strength in MPa of five samples of each example composition described below, together with the average strength of five samples of each individual carbonatable waste.
- the aggregate comprising a combination of carbonatable wastes is typically stronger than the aggregate comprising only ordinary portland cement or the aggregate comprising only a single carbonatable waste.
- First Carbonatable Waste 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Biomass Ash Carbonatable Binder: NONE Carbonation Time: 10 mins Strength: 1.842 MPa
- First Carbonatable Waste 5 g Biomass Ash Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 2.503 MPa
- First Carbonatable Waste 2.5 g Pulverised Fuel Ash Second Carbonatable Waste: 2.5 g Steel Slag Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 4.427 MPa
- First Carbonatable Waste 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Cement Bypass Dust Carbonatable Binder: NONE Carbonation Time: 10 mins Strength: 3.377 MPa
- First Carbonatable Waste 5 g Air Pollution Control Residue Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 1.857 MPa
- First Carbonatable Waste Air Pollution Control Residue Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 10 mins Strength: 2.877 MPa
- First Carbonatable Waste 25% Cement Bypass Dust Second Carbonatable Waste: 25% Pulverised Fuel Ash Carbonatable Binder: 50% Portland Cement Carbonation Time: 10 mins Strength: 5.048 MPa
- First Carbonatable Waste Biomass Ash Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 10 mins Strength: 3.509 MPa
- First Carbonatable Waste 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Biomass Ash Carbonatable Binder: NONE Carbonation Time: 20 mins Strength: 2.001 MPa
- First Carbonatable Waste 5 g Biomass Ash Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 2.942 MPa
- First Carbonatable Waste 2.5 g Pulverised Fuel Ash Second Carbonatable Waste: 2.5 g Steel Slag Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 7.483 MPa
- First Carbonatable Waste 5 g Air Pollution Control Residue Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 2.580 MPa
- First Carbonatable Waste Air Pollution Control Residue Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 20 mins Strength: 4.561 MPa
- First Carbonatable Waste 25% Cement Bypass Dust Second Carbonatable Waste: 25% Pulverised Fuel Ash Carbonatable Binder: 50% Portland Cement Carbonation Time: 20 mins Strength: 6.480 MPa
- First Carbonatable Waste Biomass Ash Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 20 mins Strength: 5.110 MPa
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Abstract
An improved process for the preparation of aggregates for use with mixtures of various carbonatable substances, in particular mixtures comprising pulverised fuel ash and/or steel slag. The mixtures also comprise a carbonatable binder. The process comprises the steps of a. blending a combination of two carbonatable wastes, b. mixing the blended carbonatable waste with a carbonatable binder, c. mixing the blended carbonatable waste and binder with water, and d. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.
Description
- This application is a divisional of U.S. patent application Ser. No. 16/098,360, which was filed Nov. 1, 2018 as a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/GB2017/051319, filed May 11, 2017, entitled “IMPROVED PRODUCTION OF AGGREGATES,” which in turn claims priority to GB Application No. 1608268.7, filed May 11, 2016. The entire disclosures of these applications are hereby incorporated by reference in their entireties.
- The present invention relates to the production of aggregates comprising air pollution control residue with a carbonatable substance. The present invention also relates to the production of aggregates comprising portland cement and air pollution control residue, cement bypass dust or biomass ash. The present invention also relates to the production of aggregates comprising two or more carbonatable wastes.
- Primary aggregates for use in concrete mixtures are produced from naturally formed rocks, stones and gravels.
- Due to the limited and increasingly costly supply of primary aggregates, research has been carried out into the production of secondary aggregates for replacing or supplementing primary aggregates in concrete mixtures.
- Embodiments of the present invention seek to provide an improved process for the preparation of aggregates, in particular secondary aggregates.
- According to a first aspect of the present invention, there is provided a process for the preparation of aggregates, the process comprising the steps of:
-
- a. blending air pollution control residue with a carbonatable substance;
- b. mixing the blended air pollution control residue and carbonatable substance with water to form a damp blended air pollution control residue and carbonatable substance mixture; and
- c. carbonating the damp blended air pollution control residue and carbonatable substance mixture in the presence of carbon dioxide.
- In this way, the first aspect of the present invention provides a process for the production of secondary aggregates comprising a combination of air pollution control residue, which is typically recovered from incineration of municipal waste, and a carbonatable (i.e. carbon dioxide reactive) substance. Such a combination provides a significant increase in the rate of hardening of the aggregate during carbonation, which enables the aggregate to be formed much more quickly than conventional secondary aggregates.
- The carbonatable substance may be cement bypass dust, biomass ash or ordinary portland cement.
- The process may further comprise the step of initially sieving or filtering or separating the carbonatable substance and/or the air pollution control residue before they are blended together. The carbonatable substance and/or the air pollution control residue may be initially sieved, filtered or separated to obtain an average particle size of less than around 0.1 mm, in particular around 0.05 mm to 0.1 mm.
- The air pollution control residue and carbonatable substance may be blended in a vessel. The vessel may be a beaker. The vessel or beaker may have a volume of around 25 ml. The air pollution control residue and carbonatable substance may be blended by hand or may be blended by a machine such as a planetary mixer.
- The weight ratio between the air pollution control residue and the carbonatable substance may be approximately 1:2 or approximately 2:1. Preferably, the weight ratio may be approximately 1:1.5 or approximately 1.5:1. More preferably, the weight ratio may be approximately 1:1.
- The blended air pollution control residue and carbonatable substance may be mixed with around 15-30% w/w of water, alternatively around 15-25% w/w of water, or alternatively around 20-30% w/w of water, or around 25% w/w of water, to form the damp blended air pollution control residue and carbonatable substance mixture.
- The process may further comprise the step of mixing the damp blended air pollution control residue and carbonatable substance mixture after its mixing with water. The damp blended air pollution control residue and carbonatable substance mixture may be mixed by hand or may be mixed by a machine such as a planetary mixer. In this way, a second stage of mixing may ensure that water is spread evenly throughout the mixture.
- The process may further comprise the step of sieving the damp blended air pollution control residue and carbonatable substance mixture. The damp blended air pollution control residue and carbonatable substance mixture may be sieved to obtain an average particle size of around 0.05 mm to 0.15 mm, in particular an average particle size of around 0.1 mm or less than 0.1 mm.
- According to a second aspect of the present invention, there is provided a process for the preparation of aggregates, the process comprising the steps of:
-
- a. blending portland cement with a carbonatable substance;
- b. mixing the blended portland cement and carbonatable substance with water to form a damp blended cement and carbonatable substance mixture; and
- c. carbonating the damp blended portland cement and carbonatable substance mixture in the presence of carbon dioxide,
wherein the carbonatable substance is air pollution control residue, cement bypass dust, biomass ash or steel slag.
- In this way, the second aspect of the present invention provides a process for the production of secondary aggregates comprising a combination of portland cement and either air pollution control residue, cement bypass dust or biomass ash, which are carbonatable (i.e. carbon dioxide reactive) substances. Such a combination provides a significant increase in the rate of hardening of the aggregate during carbonation, which enables the aggregate to be formed much more quickly than conventional secondary aggregates.
- The process may further comprise the step of initially sieving or filtering or separating the carbonatable substance and/or the portland cement before they are blended together. The carbonatable substance and/or the portland cement may be initially sieved, filtered or separated to obtain an average particle size of less than around 0.1 mm, in particular around 0.05 mm to 0.1 mm.
- The portland cement and carbonatable substance may be blended in a vessel. The vessel may be a beaker. The vessel or beaker may have a volume of around 25 ml. The air pollution control residue and carbonatable substance may be blended by hand or may be blended by a machine such as a planetary mixer.
- The weight ratio between the portland cement and the carbonatable substance may be approximately 1:2 or approximately 2:1. Preferably, the weight ratio may be approximately 1:1.5 or approximately 1.5:1. More preferably, the weight ratio may be approximately 1:1.
- The blended portland cement and carbonatable substance may be mixed with around 25% w/w of water to form the damp blended portland cement and carbonatable substance mixture.
- The process may further comprise the step of mixing the damp blended portland cement and carbonatable substance mixture after its mixing with water. The damp blended portland cement and carbonatable substance mixture may be mixed by hand or may be mixed by a machine such as a planetary mixer. In this way, a second stage of mixing may ensure that water is spread evenly throughout the mixture.
- The process may further comprise the step of sieving the damp blended portland cement and carbonatable substance mixture. The damp blended portland cement and carbonatable substance mixture may be sieved to obtain an average particle size of around 0.05 mm to 0.15 mm, in particular an average particle size of around 0.1 mm or less than 0.1 mm.
- According to a third aspect of the present invention, there is provided a process for the preparation of aggregates, the process comprising the steps of:
-
- a. blending a first carbonatable waste with a second carbonatable waste to form a blended carbonatable waste;
- b. mixing the blended carbonatable waste with water to form a damp blended carbonatable waste mixture; and
- c. carbonating the damp blended carbonatable waste in the presence of carbon dioxide.
- In this way, the third aspect of the present invention provides a process for the production of secondary aggregates comprising a combination of at least two different carbonatable (i.e. carbon dioxide reactive) wastes. Such a combination of carbonatable wastes provides a significant increase in the rate of hardening of the aggregate during carbonation, which enables the aggregate to be formed much more quickly than conventional secondary aggregates.
- The first carbonatable waste may be air pollution control residue cement bypass dust, biomass ash or ordinary portland cement. The ordinary portland cement may be out-dated ordinary portland cement.
- The second carbonatable waste may be air pollution control residue cement bypass dust, biomass ash or ordinary portland cement. The ordinary portland cement may be out-dated ordinary portland cement.
- The process may further comprise the step of initially sieving or filtering or separating the first carbonatable waste and/or the second carbonatable waste before they are blended together. The first carbonatable waste and/or the second carbonatable waste may be initially sieved, filtered or separated to obtain an average particle size of less than around 0.1 mm, in particular around 0.05 mm to 0.1 mm.
- The process may further comprise the step of mixing the blended carbonatable waste with a carbonatable binder. The carbonatable binder may be cement kiln dust or ordinary portland cement.
- The process may further comprise the step of initially sieving or filtering or separating the carbonatable binder before blending with the first and second carbonatable wastes. The carbonatable binder may be sieved or filtered or separated to obtain a carbonatable binder having an average particle size of less than around in particular around 0.05 mm to 0.1 mm.
- When the blended carbonatable waste comprises a carbonatable binder, the first carbonatable waste may be steel slag or pulverised fuel ash and/or the second carbonatable waste may be steel slag or pulverised fuel ash.
- The blended carbonatable waste may be blended in a vessel. The vessel may be a beaker. The vessel or beaker may have a volume of around 25 ml. The carbonatable wastes may be blended by hand or may be blended by a machine such as a planetary mixer.
- When the blend or mixture comprises only a first carbonatable waste and a second carbonatable waste, the weight ratio between the first carbonatable waste and the second carbonatable waste may be approximately 1:2 or approximately 2:1. Preferably, the weight ratio may be approximately 1:1.5 or approximately 1.5:1. More preferably, the weight ratio may be approximately 1:1. When the blend comprises a first carbonatable waste, a second carbonatable waste and a carbonatable binder, the weight ratio between the first carbonatable waste, second carbonatable waste and carbonatable binder may be approximately 1:2:2 or approximately 2:1:2. Preferably, the weight ratio may be approximately 1:1.5:2 or approximately 1.5:1:2. More preferably, the weight ratio may be approximately 1:1:2.
- The process may further comprise a step of mixing the blended carbonatable waste with a third carbonatable waste. The third carbonatable waste may be pulverised fuel ash or steel slag.
- The blended carbonatable waste may be mixed with around 25% w/w of water to form the damp blended carbonatable waste mixture. In particular, around 2.5 grams of water may be used. The water may be deionised water.
- The process may further comprise the step of mixing the damp blended carbonatable waste mixture after its mixing with water. The damp blended carbonatable waste mixture may be mixed by hand or may be mixed by a machine such as a planetary mixer. In this way, a second stage of mixing may ensure that water is spread evenly throughout the mixture.
- The process may further comprise the step of sieving the damp blended carbonatable waste mixture. The damp blended carbonatable waste may be sieved to obtain an average particle size of around 0.05 mm to 0.15 mm, in particular an average particle size of around 0.1 mm or less than 0.1 mm.
- The process of the first, second and/or third aspect of the invention may further comprise a step of pressing the damp blended air pollution control residue and carbonatable substance mixture or damp blended portland cement and carbonatable substance mixture or carbonatable waste mixture into a form or shape that resembles the shape of aggregate used in concrete. The damp blended mixture may be pressed into pellet form. The pressing step may occur before the carbonation step. This pressing step may occur after the blending step. The pellet form may be substantially cylindrical or substantially spherical. The mixture may be pressed into a pellet form or shape by using a pellet press. In this way, the mixture is pressed into its final shape before carbonation, whilst it is still mouldable.
- The process of the first, second and/or third aspect of the invention may comprise a step of tumbling the damp blended air pollution control residue and carbonatable substance mixture or damp blended portland cement and carbonatable substance mixture or damp blended carbonatable waste mixture. A tumbling process which may be employed is described in WO 2007/096671 A1. The tumbling may take place in the presence of carbon dioxide so that the carbonation step and the tumbling step take place concurrently. The damp blended mixture may be extruded. An extrusion process applying a force of between 50-100 N, alternatively less than 50 N, or alternatively more than 100 N, may be used. The pellet press may comprise a split mould. The split mould may be manufactured from nylon. The split mould may be around 30 mm×10 mm. The split mould may have an aperture of around 8 mm for enabling removal of the pressed pellets.
- The pellet press may comprise a plunger. The plunger may be manufactured from cast resin. The plunger may be around 32 mm×7.5 mm.
- The pellet press may comprise a retaining collar. The retaining collar may be reinforced. The retaining collar may be manufactured from nylon. The retaining collar may be around 230 mm×160 mm. The retaining collar may have an aperture of around 100 mm.
- A force of around 50-150 N may be used to cast each pellet in the pellet press. Preferably, a force of around 100 N may be used to cast each pellet in the pellet press.
- Each pellet of the damp carbonatable waste mixture may be formed from a mixture of approximately 2.5 grams of a first carbonatable waste, approximately 2.5 grams of a second carbonatable waste and approximately 5 grams of a carbonatable binder. Alternatively, each pellet may be formed from a mixture of approximately 5 grams of a first carbonatable waste and approximately 5 grams of a second carbonatable waste. Thus, each pellet may be formed from approximately 10 grams of dry material.
- The damp blended air pollution control residue and carbonatable substance mixture or damp blended portland cement and carbonatable substance mixture or carbonatable waste mixture may be carbonated in a carbon dioxide-rich gaseous environment. That is, the carbonation may be carried out in an atmosphere that has a carbon dioxide content greater than that of natural air. For example, the carbonation may be carried out in an atmosphere containing at least 50%, 60%, 70% or 80% carbon dioxide by volume. Preferably, the atmosphere may consist mostly of carbon dioxide, for example 90%, 85% or 99% by volume. The carbonation may take place in a carbonation chamber. The carbonation chamber may be fully or partially enclosed, for example the carbonation chamber may be a pan pelletiser. The carbonation chamber may have a volume of approximately 5 litres. The pressure in the carbonation chamber may be atmospheric pressure. Alternatively, the pressure in the carbonation chamber may be slightly above atmospheric pressure. For example, the pressure in the carbonation chamber may be around 2 bar. This ensures that sufficient carbon dioxide is available to maximise or complete carbonation, without unduly impacting on strength development.
- The blended mixtures of the first, second and/or third aspects of the invention may comprise any number of additional carbonatable substances or wastes blended into the mixture. For example, a third carbonatable substance or waste may be included in the blended mixture. The third carbonatable substance or waste may be steel slag or pulverised fuel ash. Alternatively, the third carbonatable substance or waste may be air pollution control residue, cement bypass dust or biomass ash.
- In order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:
-
FIG. 1 is a schematic block diagram of a process according to an embodiment of the present invention; -
FIG. 2 is a graph showing the strength of carbonatable wastes and combinations of carbonatable wastes produced by the process shown inFIG. 1 , with a carbonation time of 10 minutes; -
FIG. 3 is a graph showing the strength of carbonatable wastes and combinations of carbonatable wastes produced by the process shown inFIG. 1 , with a carbonation time of 20 minutes; -
FIG. 4 is a table showing the sources of various carbonatable wastes that are described herein; -
FIG. 5 is a table showing the % weight compositions of various carbonatable wastes that are described herein. -
FIG. 6 is a table showing the strength of pellets of individual carbonatable wastes produced by the process shown inFIG. 1 , with no second carbonatable waste and no carbonatable binder, with a carbonation time of 10 minutes; and -
FIG. 7 is a table showing the strength of pellets of individual carbonatable wastes produced by the process shown inFIG. 1 , with no second carbonatable waste and no carbonatable binder, with a carbonation time of 20 minutes. - Referring to
FIG. 1 , a firstcarbonatable waste 1 and a secondcarbonatable waste 2 are initially selected. In this embodiment, the firstcarbonatable waste 1 is cement bypass dust from cement production in the Midlands, UK, and the second carbonatable waste is biomass ash from biomass power generation in Picardie, France. The sources of the first and secondcarbonatable wastes FIG. 4 . The compositions of the first and secondcarbonatable wastes FIG. 5 . - A
carbonatable binder 3 is then selected. In this embodiment, the carbonatable binder is ordinary portland cement (52.5 N), supplied by Cemex (RTM) Ltd. The composition of thecarbonatable binder 3 is shown inFIG. 4 . - At
step 104, approximately 2.5 grams of the firstcarbonatable waste 1 is sieved to obtain a particle size of less than 0.1 mm. - At
step 105, approximately 2.5 grams of the secondcarbonatable waste 2 is sieved to obtain a particle size of less than 0.1 mm. - At
step 106, approximately 5 grams of the carbonatable binder is sieved to obtain a particle size of less than 0.1mm. - At
step 107, the sieved firstcarbonatable waste 1, secondcarbonatable waste 2 andcarbonatable binder 3 are combined into a 25 ml beaker and the mixture is thoroughly blended by hand to ensure homogeneity. The dry mixture thus weighs 10 grams. - At
step 108, the blendedcarbonatable wastes carbonatable binder 3 mixture is wetted with 2.5 grams (25% w/w) of deionised water using a dropping pipette. - At
step 109, the damp blendedcarbonatable wastes carbonatable binder 3 mixture is hand mixed for a second time to ensure that the water in the mixture is evenly distributed. The mixture is then sieved to ensure a particle size of less than 0.1 mm. - At
step 110, the damp blendedcarbonatable wastes carbonatable binder 3 mixture is pressed into pellet form using a customised pellet press. The pellet press comprises a 30 mm×10 mm nylon split mould with an 8 mm aperture to enable removal of pressed samples; a 32 mm×7.5 mm cast resin plunger and a 230 mm×160 mm reinforced nylon retaining collar with an aperture of 100 mm. - In use of the pellet press during
step 110, the nylon split mould is inserted into the reinforced nylon retaining collar and placed onto a clean stainless steel dish. The damp mixture of blendedcarbonatable wastes carbonatable binder 3 is carefully placed into the nylon split mould and the cast resin plunger is readied into position. A load of approximately 100 N is applied to the resin plunger to cast the pellet, measured by a Mecmesin (RTM) BFG500N force gauge, to an accuracy of ±0.1 N. The resin plunger is then removed carefully by hand and the nylon mould is removed from the reinforced nylon retaining collar. The nylon mould is split open using a spatula so that the pressed pellet can be removed for the mould. Five cylindrical pellets are typically produced for each mixture of blendedcarbonatable wastes carbonatable binder 3. - At
step 111, the pellets of blendedcarbonatable wastes carbonatable binder 3 are transferred to a five litre carbonation chamber containing carbon dioxide, where they begin to carbonate and harden/set. The chamber operates at a pressure of 2 bar, which is slightly above atmospheric pressure to ensure that a sufficient supply of carbon dioxide is available for carbonation of the pellets, but is not so high as to unduly impact on strength development. - At
step 112, after a period of 10 minutes, the pellets are removed from the chamber. The dimensions of each pellet are measured using a Mitutoyo (RTM) CD-6 CP measuring callipers, to an accuracy of ±0.01 mm. Each pellet has a diameter of approximately 7.7 mm and thus a radius of approximately 3.85 mm. The length ratio of each pellet is around 1.0 and thus the length of each pellet is around 7.7 mm. - Each pellet is then destructively tested to determine its compressive strength. Each pellet is placed beneath a force gauge and load is applied to the force gauge until the pellet fails under compression. A Mecmesin (RTM) BFG500N force gauge was used, to an accuracy of ±0.1 N.
- The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.
-
FIG. 4 shows the sources of the carbonatable wastes discussed below andFIG. 5 shows the compositions of the carbonatable wastes shown inFIG. 4 . - The examples described below were formed using the process as described in the Detailed Description of the Invention, except that in some examples there was no carbonatable binder added to the blend of carbonatable wastes. Five samples of each combination of carbonatable wastes were formed and carbonated in the carbonation chamber for a period of either 10 minutes or 20 minutes. Each cylindrical sample had a diameter of approximately 7.7 mm (thus a radius of 3.85 mm) and a length of approximately 7.7 mm.
- The compressive strength in Newtons of each sample was determined by using a Mecmesin (RTM) BFG500N force gauge in the manner as described in the Detailed Description of the Invention. The strength in MPa was determined by the following formula:
-
-
FIGS. 6 and 7 show the average strength in MPa of five samples of each individual carbonatable waste. These reference samples were all prepared using the process described above in the Detailed Description of the Invention, except that there no second carbonatable waste and no carbonatable binder were added to the blend. -
FIGS. 2 and 3 show the average strength in MPa of five samples of each example composition described below, together with the average strength of five samples of each individual carbonatable waste. As can be seen, after carbonating for a given period of time (10 minutes or 20 minutes) the aggregate comprising a combination of carbonatable wastes is typically stronger than the aggregate comprising only ordinary portland cement or the aggregate comprising only a single carbonatable waste. -
-
First Carbonatable Waste: 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Biomass Ash Carbonatable Binder: NONE Carbonation Time: 10 mins Strength: 1.842 MPa -
-
First Carbonatable Waste: 5 g Cement Bypass Dust Second Carbonatable Waste: 5 g Biomass Ash Carbonatable Binder: NONE Carbonation Time: 10 mins Strength: 1.748 MPa -
-
First Carbonatable Waste: 5 g Biomass Ash Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 2.503 MPa -
-
First Carbonatable Waste: 5 g Cement Bypass Dust Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 4.255 MPa -
-
First Carbonatable Waste: 2.5 g Cement Bypass Dust Second Carbonatable Waste: 2.5 g Biomass Ash Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 4.397 MPa -
-
First Carbonatable Waste: 2.5 g Pulverised Fuel Ash Second Carbonatable Waste: 2.5 g Steel Slag Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 4.427 MPa -
-
First Carbonatable Waste: 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Cement Bypass Dust Carbonatable Binder: NONE Carbonation Time: 10 mins Strength: 3.377 MPa -
-
First Carbonatable Waste: 5 g Air Pollution Control Residue Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 10 mins Strength: 1.857 MPa -
-
First Carbonatable Waste: Air Pollution Control Residue Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 10 mins Strength: 2.877 MPa -
-
First Carbonatable Waste: 25% Cement Bypass Dust Second Carbonatable Waste: 25% Pulverised Fuel Ash Carbonatable Binder: 50% Portland Cement Carbonation Time: 10 mins Strength: 5.048 MPa -
-
First Carbonatable Waste: Biomass Ash Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 10 mins Strength: 3.509 MPa -
-
First Carbonatable Waste: 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Biomass Ash Carbonatable Binder: NONE Carbonation Time: 20 mins Strength: 2.001 MPa -
-
First Carbonatable Waste: 5 g Cement Bypass Dust Second Carbonatable Waste: 5 g Biomass Ash Carbonatable Binder: NONE Carbonation Time: 20 mins Strength: 1.984 MPa -
-
First Carbonatable Waste: 5 g Biomass Ash Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 2.942 MPa -
-
First Carbonatable Waste: 5 g Cement Bypass Dust Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 8.213 MPa -
-
First Carbonatable Waste: 2.5 g Cement Bypass Dust Second Carbonatable Waste: 2.5 g Biomass Ash Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 5.424 MPa -
-
First Carbonatable Waste: 2.5 g Pulverised Fuel Ash Second Carbonatable Waste: 2.5 g Steel Slag Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 7.483 MPa -
-
First Carbonatable Waste: 5 g Air Pollution Control Residue Second Carbonatable Waste: 5 g Cement Bypass Dust Carbonatable Binder: NONE Carbonation Time: 20 mins Strength: 4.371 MPa -
-
First Carbonatable Waste: 5 g Air Pollution Control Residue Second Carbonatable Waste: NONE Carbonatable Binder: 5 g Portland Cement Carbonation Time: 20 mins Strength: 2.580 MPa -
-
First Carbonatable Waste: Air Pollution Control Residue Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 20 mins Strength: 4.561 MPa -
-
First Carbonatable Waste: 25% Cement Bypass Dust Second Carbonatable Waste: 25% Pulverised Fuel Ash Carbonatable Binder: 50% Portland Cement Carbonation Time: 20 mins Strength: 6.480 MPa -
-
First Carbonatable Waste: Biomass Ash Second Carbonatable Waste: Pulverised Fuel Ash Carbonatable Binder: Portland Cement Carbonation Time: 20 mins Strength: 5.110 MPa
Claims (19)
1. A process for the preparation of aggregates, the process comprising:
a. blending a first carbonatable waste with a second carbonatable waste to form a blended carbonatable waste;
b. mixing the blended carbonatable waste with water to form a damp blended carbonatable waste mixture; and
c. carbonating the damp blended carbonatable waste mixture in the presence of carbon dioxide;
wherein the process further comprises mixing the blended carbonatable waste with a carbonatable binder; and wherein the first carbonatable waste is steel slag or pulverised fuel ash and/or the second carbonatable waste is steel slag or pulverised fuel ash.
2. A process according to claim 1 , wherein the first carbonatable waste is air pollution control residue, cement bypass dust, or biomass ash and/or wherein the second carbonatable waste is air pollution control residue, cement bypass dust, or biomass ash.
3. A process according to claim 1 , further comprising initially sieving the first carbonatable waste and/or the second carbonatable waste before blending.
4. A process according to claim 3 , wherein the first carbonatable waste and/or the second carbonatable waste are initially sieved to obtain an average particle size of less than around 0.1 mm before blending.
5. A process according to claim 1 , wherein the carbonatable binder is cement kiln dust or ordinary portland cement.
6. A process according to claim 5 , further comprising initially sieving the carbonatable binder before blending with the first and second carbonatable wastes.
7. A process according to claim 1 , wherein a weight ratio between the first carbonatable waste and the second carbonatable waste is approximately 1:2 to approximately 2:1.
8. A process according to claim 1 , wherein a weight ratio between the first carbonatable waste, second carbonatable waste, and carbonatable binder is approximately 1:2:2 to approximately 2:1:2.
9. A process according to claim 1 , wherein the blended carbonatable waste is mixed with around 15-30% w/w of water to form the damp blended carbonatable waste.
10. A process according to claim 9 , further comprising mixing the damp blended carbonatable waste mixture.
11. A process according to claim 1 , further comprising sieving the damp blended carbonatable waste mixture.
12. A process according to claim 11 , wherein the damp blended carbonatable waste mixture is sieved to obtain an average particle size of less than around 0.1 mm.
13. A process according to claim 11 , wherein the blended carbonatable waste comprises any number of additional carbonatable wastes blended into the mixture.
14. A process according to claim 1 , wherein the process further comprises mixing the blended carbonatable waste with a third carbonatable waste.
15. A process according to claim 14 , wherein the third carbonatable waste is pulverised fuel ash or steel slag.
16. A process according to claim 1 , further comprising pressing the damp blended carbonatable waste mixture into a form or shape that resembles the shape of aggregate used in concrete.
17. A process according to claim 16 , wherein a force of around 100 N is used to cast each form or shape.
18. A process according to claim 1 , wherein the damp blended carbonatable waste mixture is carbonated in a carbon dioxide-rich gaseous environment.
19. A process according to claim 1 , wherein the carbonating takes place in a fully or partially enclosed carbonation chamber.
Priority Applications (1)
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US18/486,933 US20240043326A1 (en) | 2016-05-11 | 2023-10-13 | Production of aggregates |
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GB1608268.7 | 2016-05-11 | ||
GB1608268.7A GB2550170B (en) | 2016-05-11 | 2016-05-11 | Improved production of aggregates |
PCT/GB2017/051319 WO2017194953A1 (en) | 2016-05-11 | 2017-05-11 | Improved production of aggregates |
US201816098360A | 2018-11-01 | 2018-11-01 | |
US18/486,933 US20240043326A1 (en) | 2016-05-11 | 2023-10-13 | Production of aggregates |
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US16/098,360 Division US11840481B2 (en) | 2016-05-11 | 2017-05-11 | Production of aggregates |
PCT/GB2017/051319 Division WO2017194953A1 (en) | 2016-05-11 | 2017-05-11 | Improved production of aggregates |
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US16/098,360 Active US11840481B2 (en) | 2016-05-11 | 2017-05-11 | Production of aggregates |
US18/486,960 Pending US20240034674A1 (en) | 2016-05-11 | 2023-10-13 | Improved production of aggregates |
US18/486,933 Pending US20240043326A1 (en) | 2016-05-11 | 2023-10-13 | Production of aggregates |
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US18/486,960 Pending US20240034674A1 (en) | 2016-05-11 | 2023-10-13 | Improved production of aggregates |
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EP (3) | EP4279464A3 (en) |
CA (1) | CA3060015C (en) |
GB (1) | GB2550170B (en) |
SG (1) | SG11201809209PA (en) |
WO (1) | WO2017194953A1 (en) |
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WO2016105383A1 (en) * | 2014-12-23 | 2016-06-30 | Boral Ip Holdings (Australia) Pty Limited | Rapid setting material for improved processing and performance of carbonating metal silicate cement |
GB2550170B (en) | 2016-05-11 | 2022-10-05 | Carbon8 Systems Ltd | Improved production of aggregates |
FR3102171B1 (en) * | 2019-10-22 | 2021-10-15 | Centre Nat Rech Scient | COMPOSITE MATERIALS CONTAINING CONCRETE AGGREGATES, POROUS CARBON AND THEIR USE FOR THE REMOVAL OF GAS POLLUTANTS |
CN110922145B (en) * | 2019-12-18 | 2021-03-16 | 武汉理工大学 | Preparation method of high-strength carbonized artificial aggregate |
EP4074670A1 (en) | 2021-04-16 | 2022-10-19 | Khan, Abbas | Lightweight fine particulates produced majorly from biomass-coal combustion fly ash |
US11643593B2 (en) | 2021-05-07 | 2023-05-09 | Conocophillips Company | Proppant from captured carbon |
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JPS6046955A (en) * | 1983-08-22 | 1985-03-14 | 太平洋セメント株式会社 | Carbonation process for flyash cement pellet |
SU1286560A1 (en) * | 1985-05-12 | 1987-01-30 | Симферопольский филиал Днепропетровского инженерно-строительного института | Raw mixture for producing unburned ash gravel |
DE3525111A1 (en) * | 1985-07-13 | 1987-01-15 | Hubert Eirich | METHOD FOR PRODUCING LEAK-OUT AGGLOMERATES |
JP2002160952A (en) * | 2000-11-21 | 2002-06-04 | Sekisui Chem Co Ltd | Artificial lightweight aggregate |
US20060189837A1 (en) * | 2005-02-22 | 2006-08-24 | Forrester Keith E | Method for heavy metal stabilization and cementious agglomeration of flyash and scrubber residues |
GB0603443D0 (en) * | 2006-02-21 | 2006-04-05 | Hills Colin D | Production of secondary aggregates |
SE539437C2 (en) * | 2015-03-31 | 2017-09-19 | Stora Enso Oyj | A method of producing filler from fractionated fly ash |
GB2550170B (en) | 2016-05-11 | 2022-10-05 | Carbon8 Systems Ltd | Improved production of aggregates |
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2016
- 2016-05-11 GB GB1608268.7A patent/GB2550170B/en active Active
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2017
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- 2017-05-11 US US16/098,360 patent/US11840481B2/en active Active
- 2017-05-11 CA CA3060015A patent/CA3060015C/en active Active
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US11840481B2 (en) | 2023-12-12 |
EP3455187A1 (en) | 2019-03-20 |
GB2550170A (en) | 2017-11-15 |
GB2550170B (en) | 2022-10-05 |
EP4279465A3 (en) | 2024-02-28 |
EP4279464A3 (en) | 2024-02-28 |
CA3060015C (en) | 2023-09-26 |
GB201608268D0 (en) | 2016-06-22 |
US20190119158A1 (en) | 2019-04-25 |
EP4279464A2 (en) | 2023-11-22 |
US20240034674A1 (en) | 2024-02-01 |
SG11201809209PA (en) | 2018-11-29 |
WO2017194953A1 (en) | 2017-11-16 |
CA3060015A1 (en) | 2017-11-16 |
EP4279465A2 (en) | 2023-11-22 |
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