GB2417028A - Synthetic lightweight aggregate - Google Patents

Abstract

A lightweight aggregate is formed from a mixture of inorganic material such as power station waster ash, river dredgings, mine tailings, industrial or chemical waste, and organic material, such as sewage, agricultural waster or domestic garbage. Preferably the aggregate contains 70% inorganic materia and 30% organic material. The starting materials are mixed together and pelletised. The pellets are hardened by rolling and polishing before drying at temperatures between 100{C and 300{C. The dried pellets are then heated at between 400{C and 800{C to burn off organic components near to surface of the pellet. The pellets then undergo a final heating stage in a rotary kiln at around 1250{C. Remaining organic components are volatilised and a lightweight aggregate bead is produced.

Description

1 241 7028 The production of synthetic stone for Use as "Light Weight

Aggregate", LWA II This invention forms spherical carbon-strand "green" pellets which are converted into beads in order to enter a purpose designed ldln which metamorphoses the beads into spherical balls without distortion by bloating or clinkering.

The process converts input material into synthetic stone-aggregate particles which are generally of a lighter weight (for equivalent volume) than most natural rods particles (aggregates). The synthetically formed particles are referred to as Light Weight Aggregate particles (LWA).

Synthetic aggregates and Light Wei,3;ht Aggregates (LWA) are known, but they are not produced in the controlled manner that is described herein. . .which provides a range of improved characteristics of the synthetic aggregate. . .which provide various advantageous properties of the synthetic aggregate described within this invention.

Accordingly, this invention provides for the manufacture of a synthetic stone aggregate ball of a controlled diameter, weight, structure and surface tenure that is produced from a controlled blend of materials (and fluxes) that are processed within a range of proprietary and modified apparatus.

Thus, the invention provides a method of processing allows the production of a spheroidal ball of such controlled properties, being a ball that has not bloated, deformed or clinkered as well as a ball that has developed a predetermined finish to its "shell".

To achieve such properties of the synthetic stone-aggregate ball, the novel method of production of the pellet and the subsequent processes and process controls that are required to convert the pellet to a bead and then form a ball that has a range of unique applications are the basis of this invention.

For the creation of the primary pellets, various input materials are necessarily employed which are derived from a combination of two categories of material, namely - inorganic material (.. being a material of a generally particulate nature) - organic material (. . . being a material of a generally fibrous nature).

Both types of input are selected from various primary or source materials that are either "natural, processed or waste materials".

A control is therefore required over these input materials to ensure that the correct blend is provided in order to adequately prepare the green pellet Mom a blend of particulate material and fibrous organic material.

Such prepared pellet is termed a carbon-strand pellet.

Such potential input materials are summarised (non exclusively) as follows: a. Inorganic material input. .. (which material may have some minor form of carbon content). . . such as the following example materials (or blend thereof) - Power Station waste (ash).

- River dredgings, mine tailings....and all forms of clay.

- Industrial or chemical waste.

b. Organic combustible material input. . . (which may have some inorganic content). . .such as the following example materials (or blend thereof Domestic or farm sewage.

- Domestic and-or industrial garbage.

- Organic "agro-industrial" waste.

- Organically rich industrial waste(s).

Elements of the two categories of input materials are thoroughly blended or "homogenized" as the objective in selectively combining materiels from both of the above categories ("a" and "b') of feedstock (with any necessary fluxes and agents) is to formulate a carbon-strand green pellet which is to be progressively heated/fired in order to achieve the controlled production of a synthetic stone-aggregate (or synthetic stone ball) with improved qualities over other synthetic or natural stone parades (aggregates) To achieve such final product of a synthetic stone ball, the original green carbon-strand pellet is required to be composed of approximately 70% inorganic material, with the balance of the material being that of an organic nature (preferably of a fibrous nature).

These figures (ratios) are illustrative only and may vary by 10% (approximately) depending upon the nature of the input materials.

Such carbon-strand green pellet will, by virtue of the loss of carbon content and other volatiles, produce a synthetic stone-aggregate ball that is less dense than most conventional rodcs (with the exception of a limited number of natural materials such as pumice).

Within the construction industry, the resultant synthetic stone-aggregate product is generically known as a Light Weight Aggregate (LWA). . . by which term the synthetic stone-aggregate balls that are finally formed will be generally referred to.

Thus, whilst equalling many properties of a normal (natura9 stoneaggregate in terms of strength, hardness, porosity, insulation etc. the additional advantages of the synthetic stone-aggregate (LWA) are: Controlled weight (. . . usually being a "lighter weight',) - Controlled surface crazing/fracturing providing - Improved cementation and bonding characteristics.

- Controlled water adsorption / absorption - Controlled diameter.

- Controlled colour.

The applications for the synthetic stone-aggregate "Light Weight Aggregate" (LWA) may vary with regard to the nature and quality of the blend of input materials and the effectiveness of the process controls of the production technology employed.

Various examples of the improved usage and applications for a synthetic stone aggregate ball which will be regarded for this document (unless otherwise stated) as a Light Weight Aggregate (LWA) of a controlled diameter and surface finish are illustrated and sumsnarised within the following list..

CIhis list commences initially with uses/applications for a lesser quality LWA ball rising to uses/applications for a higher quality, more specialized, LWA ball).

List of descriptive applications of a manufactured synthetic stoneaggregate. (re LWA).

1. LWA for general bulk aggregate use. . . such as for infill use where a bulk light weight aggregate may be required for suitable ground controls. . . e.g. - Where a light-weight raft or foundation is required.

- Where a light weight roof is required (as in the mining industry) 2. LWA for road construction use. . . especially for a road base in cold climates (with perma-frost conditions).

3. LWA for general concrete use. . . especially for long distance pumped concrete usage.

4. LWA for specialised concrete use especially for bridges of a large span or high rise structures.

5. Intrinsic LWA component of pre-fabricated building modules. . . where light weight and structural integrity is required for large-span panels.

6. Intrinsic LWA component of pre-formed bitumen section-mats. . . which may be manufactured, manocuvred and laid in situ, "en bloc".

7. Other uses of such a synthetic stone-aggregate (LWA) may be developed.

i. A synthetic stone product which is so prepared as to become wholly fused (sintered) so that no appreciable leaching occurs.

ii. A synthetic stone-aggregate tilde product which may have an external annular "geodic shell" which is a ball formed from "synthetic-stone" material, whilst the centre may be a smaller ball composed of a different substance (or, a similar substance but treated differently).

Such synthetic stone-aggregate is a composite product which undergoes two cycles of production. . . The first cycle providing a ball.

The second cycle encapsulating the first ball.

In summary, whilst there are some specialist applications for a heavyaggregate the objective of the patent application that is presented herein is to provide a method of achieving the controlled production of synthetic stone-aggregate spheroid particles (balls) of a controlled weight, diameter and surface finish that meet the requirements indicated for applications 1 - 7 above.

As the major consideration is to produce a (nearly) spheroidal ball with a controlled (maintained) diameter then the preparation of a carbon-strand green pellet from a mixture of inorganic and organic material is a deliberate action, as the blending of this pellet provides the initial and ongoing control of the behaviour of the pellet during the production cycle from pellet to bead and then the final synthetic stone-aggregate ball.

The organic material employed is, therefore, deliberately pre-processed and selected for its fibrous nature (. ..fibrocity...) as well as its ability to bind, pelletise and facilitate the sintering programme for the metamorphosis from pellet to the finally produced synthetic stoneaggregate ball.

The initial (green) carbon-strand pellet is required to withstand a substantial amount of transport and progressive burnout Therefore the green carbon-strand pellet is deliberately case hardened (work hardened) using a technique of rolling and polishing which will then allow the unfired pellet to become hard and subsequently formed into a solid bead by a pre-combustion process.

At the time of pellet formation, additional coating materials may be added to change the surface characteristics of the eventual synthetic stone-aggregate balls.

Thus, the controlled blending, preparation and coating of the input materials will achieve a manufactured spheroidal stone-aggregate ball, a Light Weight Aggregate (LWA).

Such controls may achieve the variable parameters of: 1. Size and weight. with significant reference to: 2. Porosity and permeability.

3. Physio-chemical properties.

4. Strength (compressive extensive and shear) in uniaxial and tribal.

5. Surface and core textures.

6. Surface and core hardness.

7. Surface and core adsorption (and absorption) Other variable aspects may be reflected in the controlled production of the synthetic stone balls... which may include - Loss of material on ignition - Leaching.

- Degeneration and degradation.

- Abrasion.

Thus, the above permutation of "properties" of the synthetic stoneaggregate ball can create either improved singular stand alone uses or improved compound uses, where products that utilise the ball within their matrix (such as concrete or asphalt sections).

A concrete section using synthetic stone-aggregate may have the same strength as a standard/conventional concrete section. However, the synthetic stone-aggregate section will be lighter in weight due to the lesser density of the synthetic stone.

A specific example of an advantageous use of the synthetic stoneaggregate LWA is where a composite product may be created by a manufacturing process that requires the use of less cementing (or binding) matrix.

This is a feature which may be advantageously employed where a concrete section is prepared from the synthetic stone aggregate balls (LWA).

This process using synthetic stone-aggregate will then both increase the weight saving and reduce the cost of the composite section.

Also, a compound product may be manufactured with the deliberate use of more cementing (or binding) matrix. Thus an asphalt section prepared from the synthetic stone-aggregate may have the same characteristics as a conventional asphalt section, but the section with synthetic stone aggregate balls (LWA) will be more light-weight (per equivalent section) and have an improved mastic compaction due to the controlled interstitial envelopment of the maximised bitumen matrix enveloping the synthetic aggregate balls.

In summary, the objectives of the process controls contained herein are: i. To prepare a source product that may withstand breakage during the process.

ii. To produce a uniform product (constant diameter and other physical properties) iii. Maximise or minimise various physical or chemical properties of the ball (such as porosity of the ball).

A specific embodiment of this invention will now be described by way of example with reference to the accompanying Drawing in which: Figure 1 Schematic flow sheet of operations.

Figure 2 Carbon-strand pellet Figure 3 A bead. being a modified pellet.

Figure 4 A synthetic stone-aggregate ball Pigure 5 Enlarged section of a synthetic stoneregate ball.

Figure 6 A Geodic sphere Figure 7 Perspective view of kiln.

Figure 7a Cross section of kiln (across width) Figure 8. Plan view of Isiln (showing trace of lifter disturber position) Figure 9 Side view of kiln (with pivot point).

Figure 10 Cross section of kiln (with minimal lobes or lifter-disturbers) Figure 11 Cross section of kiln with triquetral lobes (or lifterdisturbers) Pigure 12 Cross section of kiln with moderate lobes (or lifter disturbers) Pigure 13 Shows rotation and rolling of pellet-ball bed.

Pigure 14 Shows transfer of pellet-ball to adjacent chamber. (oils. \g) Pigure 15 Shows bead motion for heating by foil lift Pigure 16 Crazed surface of spheroid.

Figure 17 Concrete bonding configuration of surface of shell.

Figure 18 Pour spheroid ball "packing" arrangements.

Figure 19 Three ball spheroid "packing" arrangement.

Pigure 19a Separated ball position of optimum triangular stacking pattem.

Pigure 20. Interstitial ball ratios (four ball void) Pigure 21. Interstitial ball ratios (three ball void) Figure 22 Concrete block (arrangement of ball sizes & minimised cement mortar) Figure 22a Illustration of extended section of formed concrete (panel or block).

Figure 23 Special long-span example of a concrete block (module) Figure 24 Bitumen bloclr (module). . . with optimum arrangement of ball sizes and maximised matrix content The following list identifies and summarises the various items/components referred to in the aforementioned Figures of the Drawing.

1. Particulate material (contaminated).

2. Particulate material (uncontaminated) 3. Processed contaminated materials.

4. Prepared (reconstituted) contaminated materials 5. Other fine "rained material such as PEA (powdered fuel ash) 6. Garbage.

7. Sewage.

8. Agro-industrial waste.

9. Carbon-strand fibre.

10. Blended organic fibre and inorganic particulate matter.

11. Additives for pellet preparation.

12. Pellets. (formed from pelletisation.) 12a. Polisher.

12b. Body of pellet 12.c. Body of bead.

!2.d. Body of ball.

13. Dryer.

14. Pre-furnace / kiln heater.

14a. Bead with hardened body.

15. Kiln.

15a Ball with sintered / devitrified body 16. Post furnace / kiln cooler.

17. Bed of beads (balls).

18. Shell of pellet / bead / ball.

19. Synthetic stone-aggregate ball 19.a.Internal core of compound ball.

20. Gas jets for kiln.

21. Lifter within rim of kiln.

22. Lifters spiralling around the wall of kiln 23. Angle of elevation of kiln (adjustable).

24. Heightened lifter (forming triquetral profile).

25. Foil (with perforations) providing lift for maximum radiant heat exposure.

26. Reduced profile lifter - disturber 27. Cementaceous material.

28. Concrete matrix.

29. Long section of concrete block.

30. Cavity of concrete block.

31. Shaped section of concrete block end.

32. Bitumen section.

Referring to the Drawing, from Fig. 1, it can be seen that the production process requires the initial formation of a pellet from the various input materials. . . this pellet being termed a carbon-strand green pellet Such pellet is formed from mixing particulate material which may be form various sources (1, 2, 5), with a source of carbon rich material which also may be from a variety of sources (6,7,8) It is to be noted that The source particulate material, may already contain adequate free carbon this may be the case with regard to coal-mine waste.

Contaminated materials may also be used as "particulate source" or "organic source" materials, as the process may be suitably controlled in order to allow the final synthetic aggregate stone to be formed as an inert product The finally selected input materials are blended (10) and prepared as a mixture of fibrous organic (9) and particulate inorganic materials (1,2,5).

Various additives may be required to effect final pelletisation (15).

The green pellet that is formed with the fibrous carbon content is therefore termed a carbon-strand pellet, this being the term used for the raw unformed "green pellet" (12).

The green carbon-strand pellet is then hardened by a process of rolling and polishing (12a) which process hardens the outer covering of the pellet to form a shell (18) for the pellet The hardened pellet is then dried and taken to a buffer store (silo. . .not shown) At the drying stage, the carbon- strand pellet is dried at temperatures of between to 300 deg. Celsius.

During this stage the external fissures of the pellet are opened by the combustion of the carbon strands (9) allowing low temperature gases (including a large amount of the moisture content) and most volatiles to escape from the outer zone(s) of the pellet (see figures 2, 3 and 5) It can be seen that the pre-prepared fibrous nature of the organic material (9) is a deliberate and controlling factor in the formation of the synthetic stone aggregate (19) from the subsequent heating staged ignition and sintering of the materials within the body of the orinal/initial pellet (12b).

The subsequent pre-ldln stage (or early kiln stage) where the burning of the carbon "strands" is effected at temperatures between 400 -800 deg Celsius in order to form a bead-like product (see Fig 3) This process deliberately leaves the core-regions of the bead with incomplete combustion.... but does allow for the opening of micro-fissures within the bead to allow for the complete devolatalisation and dewatering of a large part of the bead body (and core).

Thus, prior to entering the kiln (15), the pellet has been pre-heated to form a bead (14a) which has now been partially devolatalised and fully dried (Fig 3) The bead (14a) is now of an adequate strength to withstand the rigours of the passage through the kiln.

This is a transient kiln stage (this may be part of the preliminary stage or an intrinsic part of the kiln-stage) which provides the complete burnout of the bead to be subsequently effected within the kiln.

Figure 4 shows a ball which has been prepared after the burning of the carbon strands is fully completed. . . this process is finally concluded within the upper reaches of the kiln of Figure 7 (15), at which stage the entire (total carbon-strand filaments have ignited, thereby providing an initial fissure pattern for the escape of gases/volatiles. . . fissures are also used as a fusion route in the ensuing sintering process.

Within the kiln (15) the bead (14a) is metamorphosed through a process of final combustion of the core carbon-strand material (see Pig 4) which causes the internal bead temperature to commensurately increase which, when combined with the radiant temperature of the fueljet and kiln casing, causes the bead to finally sinter and reach a "plastic state".

The resultant pyro-plastic material of the bead is then cooled within the latter (upper) zone of the kiln when it is formed into a solid ball (which has retained the same dimensions as the initial pellets).... this being the synthetic stone-aggregate ball (15a) The kiln stage (.. which generally requires a process duration of some 30 to 60 minutes) provides for the complete firing of the pellet at temperatures that may rise to around or exceed 1250 degrees Celsius.

For most bead compounds and structures there will be a temperature range of some 15 degrees band (within the broader temperature band of 1100 to 1300 degrees Celsius) wherein the bead will demonstrate pyro-plasticity within this band.

At the temperature of pyro-plasticity, the movement of the bed of beads (the bead-slurry), will become sluggish (. . .as the beads become more plastic like and "sticky).

The beads need to be held at this critical temperature for some 5 -10 minutes to ensure that there is complete vitrification of the core of the bead.

On cooling of the bead, with devitrification of the bead, the bead is transformed to be a solid ball (a synthetic stone-aggregate spheroid).

The aggregate (bald is then cooled (16) and stored in bins (not shown) Given the controls of the pellet to bead to ball process, it is apparent that a systematic method of controlling the pellet as it metamorphoses through this process is required.

Thus given the inevitability of a variable nature of the input material and the probability for the requirement (specification) of a variable diameter, then * is necessary to be able to control the following elements of the given process cycle.

a. The work hardening of the surface of the pellet.

b. The drying process of the carbon-strand pellet c. The partial combustion of the pellet as * becomes bead.

d. The complete burn-out and devolatalisation of the bead.

e. The pyro-plasticity of the bead.

f. The vitrification (and devitrification without clinkering) of the ball.

The preparation, movement and handling of the pellet (and its protection) is important to the production of a synthetic stone aggregate.

Figure 2 shows The green pellet (12) with a work hardened shell (18).

The matrix material (12b) being the particulate material (1,2,5).

The carbon strand material (9) being the organic material (6,7,8,11) Figure 3 shows an intermediate bead (. . . a hardened pellet, 14a) A hard bead (14a) has been formed with most of the outer zone of carbon material having been used within the formation of the bead by heating.

This process also causes and allows devolatalisation and final drying of the inner material of the bead.

The carbon strand material (9) can be seen to be reduced to an inner core amount.

Figure 4 shows a near finished synthetic-stone aggregate (15a) A hard ball (15a) has been finally formed through the complete ignition of the carbon material and sintering of the particulate material to provide the final core material (12d) Figure 5 shows an enlarged view of the shell (18) of the pellet (12) Illustrates that the carbon-strand matrix of the pellet permeates through both the body of the pellet (17) and that of the shell..

It shows that, at pellet stage, the carbon strands are also contained both within the work hardened rim (18) and within the core (12b) of the sphere.

Figure 6 shows a view of a compound synthetic stone-aggregate ball.

This is a ball (19) that is created with another ball (19a) at the core or nucleus of the compound ball.

The original carbon-strand green-pellet (9, 12) is work hardened and heated (before proceeding to enter the kiln) in order to provide a surface "shell" that will withstand the subsequent process technology required.

The sequence of which process for the formation of the shell is: - Removal of moisture.

- Devolatalisation.

- Forming of a hardened shell (semi-crazed or fully compounded).

It is imperative for the bead that enters the kiln to have a hard but partially crazed shell in order to prevent bloating (which may occur through the lack of passages that are available to the internal gases which are created during the kiln operation or passage).

The objectives in "firing" the bead to form a synthetic stone-aggregate ball are to produce the optimum spheroidal aggregate (without distortion) that is possible.

To achieve this objective then the controls for the production of the LWA are summarised where: - The pre-kiln stage must be duly controlled in order to provide a satisfactory input of carbon-strand green pellets into the kiln.

- Once within the kiln process then the pellet must be "cooked" (sintered or "crystallized') by a process that may take from 30 to 60 mine.

Figure 7 shows a schematic perspective of the kiln, 15, with an input section of beads (14), gas jets (15) and output section of balls (16) Figure 7a shows a schematic cross section (front) with a bed of beads resting between "lifters and disturbers" (21, 22) that are set into the side of the wall of the kiln.

The depth of bed and the time that is required by the pellet is the controlling factor of the throughput quantity of the kiln The optimum throughput of the bead is achieved by this balance of pellet preparation and kiln design, proving the ability to effectively turn and roll the pellet, so that it is not "lying suspended" within the slurry-bed, thereby exposing the pellet/bead to an optimum temperature zone.

Such exposure is also effected at a specific time in the kiln cycle. . . which control is effected by the ability to control the speed of the beadball in its passage through the kiln Also, for the optimum treatment and processing of the bead during its passage though the kiln, it needs to be subject to a temperature that - may be rased/lowered in a controllable manner - may be located at a specific point within the body of the kiln.

Thus the semi-processed pellet (the bead) is entered into a kiln which may have a cross section that ranges from planar (circular or elliptical to a multi-lobate cross section which may be of tri-lobate or triquetral section that is created by the positioning of at least three longitudinal rows of lifter bars which are anally mounted to the rim of the kiln in a linear or spiral form).

As previously stated, within such kiln the pellet is required to be exposed to the maximum radiant heat (in a controlled manner) in order to optimists and maximise the results of the kiln (. . .within the optimum period of time. . . ) Given that the beads form a "bed" .....within the kiln (15) then, such bed needs to be as large (deep) as possible.

Such depth is retrained by the design of the kiln and the requirement(s) of the beads to be agitated and rotated to ensure that all beads are adequately fired through sustained exposure to the radiant heat that is produced within the lriln from both the air flow and from the reflected heat form the kiln surfaces.

Each bead must enter the kiln, join the bed of other beads (17) and migrate to the exit point of the kiln where it is to be discharged without being damaged.

The use of lifters or disturbers allows the kiln to be operated by ensuring that the beads-balls are appropriately rolled or slewed/slurried at strategic times and locations in their passage through the kiln.

Thus, the kiln (furnace) of fig 15 is shown to have an inner surface which may include a number of lifter-disturber units, which are units mounted into the side wall of the kiln.

Three longitudinal rows of lifter-disturbers may be optimal....as shown The lifter-disturber may be fabricated in sections or it may be a continuous longitudinal or sectional mouldings.

Figures 7a, 8 and 9 show that - Lifter-disturber rows are generally coaxial.

- Lifter-disturber rows may be "spiralled" to create an Archimedean effect in order to draw the bead-ball through the lazily.

- The kiln may be inclined with the angle of inclination (23) changed during production in order to vary the throughput parameters of the beads/balls.

Figures 10, 11 and 12 show that - Lifter-disturber (21) may be profiled so that they vary their size and shape along the length of the kiln.

- The lifter-disturber may provide a web of varying height form the wall of the kiln - The lifter-disturber may be shaped as a foil (fig 11) in order to pronde the optimum exposure of the pellets to the radiant heat by being perforated (in part. . . not shown) and providing both lift and individual exposure to the radiant heat The following figures show that the lifters (disturbers) are shaped so as to lift and disturb at optimum times.

Fig 13 shows that the pellet (18) is repeatedly turned (rotated) from a basal layer to a surface Dyer position Fig 14 shows that the pellet is exposed to the maximum radiant heat envelopment through being singularly exposed to the maximum kiln heat (at the "hot spot" of the kiln).

Fig 15 shows that the profile of the kiln has been modified in order to protect the material in its state of pyro-plasticity. The profile has been subdued in order to provide a controlled rolling

movement and minimal surge at this time of plasticity.

In summary, the lifter-disturber (21) may be formed in sectional modular parts, or it may be a continuous moulding (and may be made wholly or in part of a refractory steel or other suitable material).

- Typically there will be three lifters in place providing a cross section as shown in figures 10,11 and 12.

The lifter (or the apex of the lifter-disturber) being of refractory steel and may be shaped or perforated in order to allow the bead to directly contact the radiant air stream.

Such lifters may be set to slightly digress from the kiln axis as plotted in the plan/elevation of the kiln in figures 8 and 9 (22), where they are shown to diverge form from the axis of the kiln (15) so as to spiral and thereby provide a longitudinal screw effect Such screw effect will assist in transporting the bed of pellets along the length of the Kiln /Z The ability to prepare the carbon-strand pellet in specific and controlled sizes (diameters and weights) also provides an advantage in the heating process of the bead (and balls) as, when the pellets-beads-balls are the same size, the radiant air may circulate the bed of beads with the optimum capacity..

Figure 7a which shows a bed of beads/balls (17) through which radiant air can readily pass when the bed is a batch of beads/balls of the same size.

The bed of beads/balls (17) within the Isiln is primarily heated by radiant air from a gas jet burner system.

The jets (20) may more than one in number.

They may be located at the front or rear of the kiln (15) . . .(or both).

With regard to the flow of the bed of beads (17), the jet (or set of jets) may act contra- current flow (or concurrent flow).

A contra current flow has the advantages of Exhausting materials (dust) away from the lowest point.

Allowing materials (beads) to enter without fouling the incoming jet.

One jet (or set of jets) may act contra current with the flow of the bed.

This the advantages of It is probable that the Odious Velvets would not be of the same size. . . and that the jets may be independently controlled to support each other to provide a discretely managed or controlled heating arrangement along the length of the Isiln.

Such control would allow the linear temperature gradient of the kiln to be varied as well as to vary the location of the maximum temperature.

Such arrangements of the fuel jets thereby assist the controlled heating of the kiln (and the controlled cooling of the Isiln) To assist in the rate of throughput of the beads-balls, the ldln may be inclined.

Figure 9 shows that the entire kiln body may be inclined by the angle "theta" (23) at a pivot point (23a) In summary, the entire firing process of the kiln is monitored with probes. . . so that within the kiln the temperature can be recorded. . . and the "hot spot" of the kiln monitored and re-positioned.

Figure 7 may be interpreted as showing schematic heating zones of the kiln where: Pre- Kiln v Zone 1 introduction of pellet. . . pre-heated. . . Start Kiln w Zone 2 bead entry temperature to kiln Mid-kiln x Zone 3 maximum temperature within Kiln End kiln y Zone 4 ball departure temperature.

Post kiln z Zone 5 ball cooling temperature.

The controls that have been described allow the beads to enter into Zone 2, progress within the kiln to Zone 3 (towards the centre) where the hottest zone may be when the bead is formed into ball and then progress to the latter part of the kiln as the ball is maturing and cooking.

Upon leaving the kiln, there is a deliberate and controlled period of cooling of the synthetic stone aggregate ball within a cooler (163.

On achieving the required control of formation and process of the pellet then the synthetic stone-aggregate ball (LWA) that has been produced may be able to be used in a variety of advantageous manners where: For composite purposes, Figure 16 shows the shell (18) of the ball (19) with a crazed and "fractured" surface (18a).

However, such surface can be controlled to be a smooth surface by Repeated rolling of the bead prior to plasticisation.

Repeated rolling of the ball post plasticisation.

From an adherence perspective, Figure 17 shows that the crazed surface (18a) of the ball will allow and encourage bonding (27) etc. However, if concrete is being formed, such surface also allows adsorption of water from the cement. therefore a smooth surface may be more relevant for some fonns of concrete world However, if asphalt is being formed, then a crazed surface may be more suitable.

Thus, given both the ability to control the surface adherence and the ability to make specific diameters of the synthetic stone-aggregate (LWA) spheroidal balls, then in a typical cross section of a bed of spheres, it may be seen from figures 18 and 19. . . It may be seen that if the diameter of all of the spheres are the same (equa0, then In figure 18, the packing of the loose spheres shows would indicate: High compressive strength, but low shear strength In figure 19, the packing of the spheres would indicate: High compressive strength and high shear strength.

Also, it can be seen that the amount of void space is summarised as Figure 18, void space is a maximum.

Figure 19, void space is a minimum.

It may be concluded that the most natural state of rest for a bed of uniform sized pebbles will be that as illustrated by fig 19.. . but such array does not promote good cementation by surrounding material.

Thus, given that an optimum concreted structure would be that with a configuration similar to Fig 19a, where the spheroid balls are nested but with a controlled interstitial separation to allow for cement encapsulation.

It is also possible to reduce the interstitial separation to a minimum, Hereby affording the minimum cement usage. /!

Thus, it is herewith advised that a lightweight concrete (using less cement than normal) but of a substantial strength may be produced (as shown in Fig 22) The ability to use two sizes of synthetic stoneaggregate ball is important as is shown in the following geometric summaries. . . where all figures are presented as approximate figures as the geometric relationship is presented as primarily illustrative.

Figure 20 shows the geometric inter-relationship between the diameters of two balls for a cubic nesting pattern. . . where the ratio of large to small ball diameter may be shown to be: 2 to 1 (approximately) Figure 21 shows the geometric inter-relationship between the diameters of two balls for a triangular nesting pattern. . . where the ratio of large to small ball diameter may be shown to be: 7:1 (approximately) Thus, it may be shown that an improved concrete product may be produced using two controlled sizes of aggregate ball (spheroid).

Fig 20 shows that such ratio is 2: 1. . . providing a maximum matrix and maximum encapsulation Fig 21 shows that such ratio is 7: 1. . . providing an optimum matrix with minimum encapsulation.

Thus, using these two references, then in the making of concrete products if the ratio of the diameter of the larger spheroid 1) to the diameter of the smaller spheroid (D2) is fixed at a ratio of 6: 1...

Then the statistical ability to maintain the optimum (minimaQ interstitial cavity for cementation for the preparation of concrete products is maximized.

It may be concluded that, using two diameters of balls then, given adequate agitation and mixing, such bedding nature is such that in the production of a synthetic panel or block of a concrete product (. . .or asphalt product). . .then it may be concluded thac- i. The contact relationship of the two spheroids provides for a stronger bed (or wall).

ii. The amount of interstitial cement is controllably optimised.

Figure 23 shows that a concrete section may become substantially extended beyond the dimension that may be achieved using conventional concrete materials (and methods).

An example of such use is when the stone-aggregate is moulded into a block which may be formed with a substantial length (as shown in sketch of Fig 23) when the additional length is supported (sustained) by virtue of:- The reduced weight.

The adequate/enhanced bonding (given the reduction of mortar content).

The mould design. /(

Rather than seek to use the minimum of material for interstitial bonding and aggregate envelopment, we may actively seek to use a "maximum" of bonding and envelopment material.

Figure 24 shows a bitumen sub base for which the primary objective is that of elasticity (and shock absorbance) of the base material, then it may be generally proposed that In this example, the ratio of D1 to D2 is 1.8 ensuring that the maximum encapsulation is achieved.

Then on employing a ratio of 1.8: 1, then such ratio would ensure that the ability for the larger spheroids to contact each other would be minimised.

Thus whilst the geometrical relationship has been presented as illustrative, it is herewith stated that the ability to manufacture a spheroid of at least two specific sizes and then blend a composite material with controlled/measured ratios) which provides the maximum opportunity to achieve a controlled configuration of a compound mass.

This may be summarised in the example of the creation of a concrete block which uses the constituent materials (in controlled ratios) of- - LWA Ball 1.

- LWA Ball2.

- Mortar.

- Additives (where necessary).

The aforementioned usages of the light-weight synthetic stone aggregate balls (LWA) requires or employs the use of a matrix material to both bond and support the bans.

However, the LWA may also form a useful product when it is employed without the use of such matrix materials (mortars or fills).

Such usage is particularly illustrated where a large volume light-weight body may be required to be created....as demonstrated in the creation of a land-fill, raft or barrier.

In such case, the loose LWA balls may be delivered into the containing body, cavity or chamber in a dry form To achieve the delivery of such dry fill process, the LWA balls may be transported as a dry slurry. . . as the LWA "balls" provide an ideal physically shaped unit of transportation as their light-weight spherical nature allows them to be readily transported (... with compressed air possibly being used, for example, to support the transportation mode).

Thus, high volumes of such dry-a,regate-slurry may be delivered over large distances within a conduit, channel or pipe-work system.

Also, if the delivery path of the slurry is downward, such dry-ballslurry will probably be capable of being delivered without assistance (by virtue of gravity and the movement provided by the spherical nature of the "balls).

However, if there is a problem in the delivery mobilisation then, in the case of a piped delivery system, the required flow-movement may be facilitated by a system of gate valves and air jets that are strategically located along the lengd1 of the pipe-work.

Other systems may require a mechanical agitation system to be employed in order to facilitate movement along such respective systems(. . . this may be especially useful in the case of unblocking pipes). /(

The advantage of delivering the synthetic stone aggregate balls into a large chamber as a dry fin are many. .. especially if the dimensional body of the fill is required to be as lightweight as possible.

To further achieve such lightweight capability, the slurry may be composed of a controlled ratio of ball sizes. . . which ratio maximises the interstitial void spacing within the body of the chamber, thereby providing an overall lighter weight for the entire volumetric body that filled.

This rnaximised interstitial void dimension also provides the fined body with a tremendous porosity.

Such porosity is very useful in terms of water/fluid expulsion and drainage (...the rapid execution of which also supports the continuing light weight nature of the fiUed-body) It is to be noted that the ordinal formulation of the aggregate (70% notional particulate content) may be varied in order to achieve a particularly light weight aggregate.

In such case where a very light weight aggregate is required then additional carbon material may be employed which, upon ignition will furdler reduce the weight of the bead-ball.

Also, depending upon the actual nature of the input materials to be blended, bloating of the bead-ball may be strategically controlled by either increasing (or decreasing) the content of the carbon material and particulate material.

Such bloating will reduce the density of the final bead-ball, but it will detrimentally reduce the controlled sphericity of the bead-ball.

In a similar vein to the above descriptions, a heavier aggregate may be formed by both reducing the carbon input and or modifying the particulate input.

In such scenario, a heavy particulate element may be employed such as iron-ore waste which, when similarly processed will also form a spherical aggregate....

which may be deliberately manufactured so as to form an aggregate which is much heavier than a conventional stone aggregate.

Thus, such heavy aggregate may be used in the following manner - With a mortar or matrix as a specialised form of concrete or mat

product. . . as per previous descriptions.

- As a dry slurry where a "heavy plug" is required.

A specific example of such usage is in the case of the drill holes of the oil industry (....where a drilling mud that is used independently is of insufficient density for such purposes...) In such case, the unconsolidated "heavy aggregate" may be readily removed when the drill hole is required to become operational. /?

Given the above described range of usage of the synthetic aggregate, it may be observed that hybrid usages of the synthetic-aggregate are also possible.

Such hybrid arrangements may be illustrated where: The wall of the fill chamber of a dry slurry light-weight aggregate may be created from a light-weight aggregate concrete block structure.

The chamber may then be filled with lose aggregate, thereby producing a dimensionally controlled light weight body.

The floor, wall or roof of a structure may be made from sectional panels or blocks of the synthetic aggregate.

Such synthetic aggregate block or mat sections may vary in strength and/or density and may be interlocking, frame mounted or independent thereby providing an optimum method of assembly and/or construction. fig

Claims (31)

laims.

1. A synthetic stone aggregate ball of a controlled diameter, structure and surface texture that is produced from a blend of materials (and fluxes) that are processed within a range of proprietary and modified apparatus(i).

2. A synthetic stone-aggregate ball as in Claim 1 that may be produced in a controlled and sustained manner to be maintained in a single or variable dimension (diameter/volume /weight)

3. A synthetic stone-aggregate ball as in Claim 1 and 2 that utilises a specified blend of material that is of a combined particulate and organic nature.

4 A synthetic stone-aggregate ball as in claims 1, 2 ad 3 that results from the utilization of carbon strands that permeate the entire body of the ball to assist in the progressive metamorphosis of the virgin "green pellet" to create the manufactured synthetic stone-aggregate.

5. A synthetic stone-aregate ball as in Claims 1, 2, 3 and 4 that results form a green pellet that has been rolled and polished in such a manner as to create a rim (shell) that is zoned so as to allow the pellet to be fully dried before it enters the necessary kiln stage of the process.

(Such pellet may be coated in order to assist in the preparation of the optimum shell structure).

6. A synthetic stone-aggregate ball as in Claims 1, 2, 3, 4 and 5 that results from a bead that is formed without bloating or distortion of the green pellet that is formed into a hardened, dry and devolatalised bead.

7. A synthetic stone-aggregate ball as in Claims 1, 2, 3 4, 5 and 6 that results from a bead that is converted into a state of pyro-plasticity within a kiln, where such pyro-plastic state may be controlled by an operator (or control system) so as to avoid distortion of the bead as well as to prevent clinkering within the slurry-bed of beads or balls.

8. A synthetic stone-aggregate ball as in Claims 1, 2, 3, 4, 5, 6, and 7 that is the result of the controlled formation of a pellet and a subsequent bead which, on final sintering of the residual materials provides a ball that is both chemically inert and/or non leachable.

9. A synthetic stone-aggregate ball as in any of the above Claims that is formed within a kiln that can be controlled so that the bed of material within the kiln may be transported along and through the kiln at variable depths and velocities.

10. A synthetic stone-aggregate ball as in any of the above Claims that is formed within a kiln that controls the motion of the input beads and output balls so that they are rolled or "slurried" and suitably exposed to both radiant heat (from the airstream and body of the kiln) as well as contact heat form the walls of the kiln (and other beads).

11. A synthetic stone-aggregate ball as in any of the above Claims that passes through a kiln that may be monitored by external thermal sensors so that the internal temperature regime is controlled and said "temperature zones" can be physically and or remotely relocated along the length of the kiln.

12. A kiln as in any of the above Claims that has multiple gas jets that allow the control of the temperature within the kiln both in amount and location.

The arrangement of such jets would allow the controlled lower temperature zones to be at the point of entry and exit of the kiln whilst the hot spot is positioned in the central part of the kiln. (...Also, the control of such jets would create a suitably improved exhaust system, which is also a dust control system).

13. A synthetic stone-aggregate ball as in any of the above Claims that passes through a kiln that may be inclined so as to deliberately control the flow of beads so that when the position of the "hot-spot" of the beads that are being plasticised moves within the kiln

14. A synthetic stone-a,ggregate ball as in any of the above Claims that has been produced by passing through a kiln that may have the transient bed of beads/balls deepened or reduced (thinned) so as to deliberately control the speed of the flow of beads.

15. A synthetic stone-aggregate ball as in any of the above Claims that has been produced by a kiln that uses lifters-disturbers that are profiled along their length (and across their section) that are not necessarily co-axial with the lriln so that the bed of beads-balls is controlled in both their effective heating and in their transient passage through the kiln.

16. A synthetic stone-aggregate ball as in any of the above Claims that is produced from spheroidal shaped bodies which allow an increase in the body of radiant air to pass through the body of the bed of balls located within the kiln.

17. A synthetic stone-aggregate ball as in any of the above Claims that is the compound result of a synthetic stone-aggregate shell being formed around a nucleus of another sphere.

18. A synthetic stone amegate ball as in any of the above Claims that has a shell that may be controlled to be "crazed " with a number of hairline surface apertures.

Such apertures/fissures allow the pellet to dry and harden into a bead without distortion, which then allows the bead to plasticise so that the stone-aggregate ball is formed without distortion.

19. A synthetic stone-aggregate ball as in any of the above Claims that is manufactured to have a hairline crazed finish to its final shell (in order to provide a keyed surface for cementation if required) or a smooth finish to provided to its final shell (when adsorption / absorption may be required to be maintained at a minimum).

20. A set of synthetic stone-aggregate balls that is produced from at least two specific and controlled diameters. Sudh set allows the controlled packing of said balls within a composite cementaceous body so that the amount of cementing or binding material that is used is a minimum, whilst the integral strength of the composite body is improved.

21. A set of synthetic stone-aregate balls as in any of the above Claims that creates and supports a composite unit that retains its integral strength over a large span so that it may be used as a light weight construction panel or block.

22. A set of synthetic stone-aggregate balls as in any of the above Maims that allow the packing of such balls within a composite body so that the amount of binding material that is used is a maximum

23. A set of synthetic stone-aggregate balls as in any of the above Claims that supports the formation of a composite body where the integral strength (or durability) of the body is retained but there is also an improved mastic capacity due to the controlled interstitial envelopment of the maximised mastic matrix enveloping the sets of synthetic aggregate balls.

(An example of the use of such body would be in the formation light weight asphalt blocks).

24. A set of synthetic stone aggregate balls as in any of the above Claims that supports the formation of a slurry which, by virtue of it's the light weight and near spherical nature of the slurry enable it to be transported over substantial distances as either a dry or wet slurry.

(Such transportation distances may be regarded as being longer distances than those of a normal or conventional slurry). Lo

25. A set of synthetic stone aggregate balls as in any of the above Claims that supports the formation of a slurry that may be readily transported more rapidly than a normal or conventional slurry.

26. A set of synthetic stone aggregate balls as in any of the above claims that supports the formation of a dry fill (of a chamber or cavity etc) by LWA.

27. A set of synthetic stone aggregate balls as in any of the above claims that supports for formation of a dry fill where the interstitial void packing space is maximised by the use of LWA balls of specified sizes.

28. A set of synthetic stone aggregate balls as in any of the above claims that use materials so that they form a heavy aggregate.

29. A set of synthetic stone aggregate balls that are of a heavy nature that are used in a manner as described by any of the above claims.

30. The production of synthetic stone aggregate bass that are made from the materials described within this disclosure and any other materials that may be suitable such as from metal, ceramic,

31. The production as substantially described herein with reference to the figures - 24 of the accompanying Drawing.