WO2017175240A1

WO2017175240A1 - Autoclaved fly ash bricks and method of manufacturing the same

Info

Publication number: WO2017175240A1
Application number: PCT/IN2017/050125
Authority: WO
Inventors: Mehmood Pracha
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-04-05
Filing date: 2017-04-02
Publication date: 2017-10-12
Anticipated expiration: 2018-10-05

Abstract

Autoclaved fly ash bricks, tiles, curb stones, blocks etc. and method of manufacturing the same are disclosed. In an embodiment of the present invention, there is provided a process of manufacturing fly ash bricks, wherein the pond ash or fly ash is used up to 92% with or without siliceous sand after mixing with burnt lime powder or hydrated lime power or sludge of acetylene gas, oxygen gas and water. The process is carried out by reacting the mass followed by giving shape to the bricks etc. by high speed robotic mechanical or hydraulic presses and finally cured in autoclaves to produce good quality bricks etc.

Description

AUTOCLAVED FLY ASH BRICKS AND METHOD OF

MANUFACTURING THE SAME

TECHNICAL FIELD

[0001] The present subject matter described herein, in general, relates to a field of building materials/shaped articles that are formed from fly ash and to methods of forming such articles. The invention has been developed especially, but not exclusively for the manufacture of structural elements and the invention is herein described in that context. However it is to be appreciated that the invention has broader application and may be used for the production of a vast range of articles, both structural and nonstructural and more particularly to a method of manufacturing the autoclaved fly ash bricks, tiles, curb stones, blocks etc. The same results in eco-friendly and improved quality of such articles.

BACKGROUND

[0002] Fly ash has been used largely as a filler material and is also used partly for production of bricks using FAL-G technique where gypsum and cement are used as a binding material. The fly ash bricks are generally made by mixing lime, sand and fly ash. In some cases, accelerators are also added to the mixture. These bricks are suitable for use in stonework and are one of the important construction items.

[0003] Using fly ash as the raw material for the bricks manufacturing is advantageous in various ways over using clay or other conventional brick manufacturing materials. Some of the advantages include uniform shape, pleasing colour like cement, light weight, less water absorption, less porous etc. Also fly ash bricks are eco-friendly as it protects the environment though consumption of large volumes of fly ash, which if disposed is a threat to the environment. A large quantity or fly ash is a by-product of various thermal power plants. [0004] The bricks manufactured by using FAL-G process require sun drying and are by and large blackish in colour, it takes longer duration for production and also large areas of land . [0005] Further many more work has been done in the area of manufacturing fly ash bricks, however many drawbacks exists with the existing technology such as water absorption exceeds the specified limit of BIS standard 12894, not having a provision for having a frog, not having capacity to produce hollow or holed bricks, usage of nonrenewable resource e.g., quick lime (burnt lime) or hydrated lime powder, sand etc., use of robotic mechanical presses, minimum of 20 percent sand is required in present technique, heavy power consumption etc.

[0006] Autoclaved fly ash brick wall is a new material, widely used in interior, exterior, and basic types of civil buildings, public buildings and industrial plants. Conventionally, autoclaved fly ash brick is formed using power plant fly ash and lime and plaster off Okinawa as the main raw material, and adding a certain amount of cinder or other aggregate, raw materials through processing, mixing, digestion, refining rolling, pressing, high-pressure steam. Autoclaved fly ash brick is an energy saving, utilizing waste of new building materials in the production process, energy saving than the average production of building materials. However, the existing manufacturing processes take longer time for autoclaved fly ash bricks productions.

[0007] Considering the above drawbacks in the present technology, there is need for a world class eco-friendly construction material at reasonable price, with bulk production capacity in a short time, utilizing pollutants like ash and slag, with reduced power utilization.

[0008] The above-described deficiencies of today's autoclaved fly ash brick manufacturing techniques are merely intended to provide an overview of some of the problems of conventional autoclaved fly ash brick manufacturing techniques, and are not intended to be exhaustive. Other problems with conventional autoclaved fly ash brick manufacturing techniques and corresponding benefits of the various non-limiting embodiments described herein may become further apparent upon review of the following description.

SUMMARY

[0009] This summary is provided to introduce concept related to autoclaved fly ash bricks and method of manufacturing the same, and the same are further described below in the detailed description.

[0010] A main objective of the present invention is to solve the problems as recited above by providing an improved method of manufacturing autoclaved fly ash bricks, tiles, curb stones, blocks etc. [0011] Accordingly in one aspect the manufacturing of autoclaved fly ash bricks, tiles, curb stones, blocks etc requires a fly ash or a pond ash with/without impurities up to 92%; lime content between 8-10%; and/or sludge content between 15- 25% as raw material or a mixture of both. [0012] According to another aspect of the manufacturing of autoclaved fly ash bricks, tiles, curb stones, blocks etc require water in quantity of 200-250 ltr per 1000 kg of mix, a quantity of dissolved solids up to 500 ppm and PH level in between 6 - 8.

[0013] In a first possible implementation, an autoclaved fly ash bricks, tiles, curb stones, blocks etc according to the above aspects includes the fly ash obtained from the boiler of a thermal power plant containing the carbon content preferably obtained as loss on an ignition at 1000 deg C temp, the ferric oxide (Fe203 in R203), and the sulphur preferably as sulphur dioxide. In one embodiment, the carbon content is preferably up to 7%, the ferric oxide is preferably up to 18%, the sulphur preferably up to 0.2%, the sulphide is preferably up to 1.95 gm/cucm, and the granulation is preferably up to residue of 5% of 0.06 mm of mesh.

[0014] In a second possible implementation the autoclaved fly ash bricks, tiles , curb stones, blocks etc according to the above aspects further include impurities and foreign material, preferably siliceous sand, acquired during the transportation from production to storage and/or during long period of storage.

[0015] In a third possible implementation, in manufacturing autoclaved fly ash bricks, tiles, curb stones, blocks etc according to the above aspects, the lime includes contents of active calcium oxide, contents of magnesium oxide, granulation of quicklime (optional), residue of sieve mesh, or any combination thereof, the contents of the active calcium oxide is more than 80%, the contents of magnesium oxide is to be below 2%, the granulation of quicklime (optional) preferably of 0.063 mm up to 0.1%, and the residue of sieve mesh preferably of 0.08 mm up to 80%.

[0016] In a fourth possible implementation, in manufacturing of autoclaved fly ash bricks, tiles, curb stones, blocks etc according to the above aspects, the sludge includes a sludge of acetylene, oxygen gas plants are preferably up to 15-25 % (depending on nature of sludge including percentage of CaO).

[0017] In a fifth possible implementation, the manufacturing of autoclaved fly ash bricks, tiles, curb stones, blocks etc are done using hydraulic presses and new moulding system. The autoclaved fly ash bricks manufactured using hydraulic presses and new moulding system further includes one or more frogs or key, wherein the frog or the key helpful in increasing a grip of one fly ash brick with adjoining fly ash brick in the brickwork and also helps in reduction of overall weight by preparing hollow and holed fly ash bricks etc. [0018] According to another aspect, a process of manufacturing of autoclaved fly ash bricks etc is disclosed. The process includes the steps of dosing of a fly ash or a pond ash, lime and sludge to mixer, wherein water is added to make a homogeneous mix and then the homogeneous mix is allowed to stay in reactor for at least ½ to 4 hours; the mass is cured and calcium hydration process is carried out , if necessary second wet mixing of the mass is carried out to ensure appropriate moisture content, shaping the products is done with the use of automatic high speed mechanical/hydraulic press along with stacking device with automatic insertion in the autoclave, hardening the semi made and shaped products is done in autoclaves at around 200 PSI (13.60 ATM) and at around 250 degree temperature which are further varied as per requirement, wherein when the semi-product (the homogeneous mix shaped) is heated under the elevated temperature, the lime and the fly ash or the pond ash particular react thereby producing calcium silicate, which binds the grains of sand and/or fly ash forming the product ; and thereby shaping the semi-product in the shape of bricks etc using high speed press and curing the finalized product by steam to form autoclaved fly ash bricks etc.

[0019] In a first possible implementation of the process according to the above aspect, the sludge includes a sludge of acetylene, oxygen gas plants are preferably up to 15-25 % (depending on nature of sludge including percentage of CaO).

[0020] In a second possible implementation of the process according to the above aspect, during stay in reactor the homogeneous mix is cured and calcium oxide hydration process is accomplished.

[0021] In a third possible implementation of the process according to the above aspect, further includes second wet mixing, if necessary, of mass to achieve appropriate or required moisture content. [0022] In a fourth possible implementation of the process according to the above aspect, a steam required for hardening process is provided by a boiler, the hardening process preferably takes about 4 - 5 hours. [0023] In a fourth possible implementation of the process according to the above aspect, the high speed press is a hydraulic press.

[0024] In contrast to the existing manufacturing processes, the present invention utilizes selective proportion of ash, sand, lime /sludge for the production of autoclaved fly ash bricks and by the pressure in the presses as per the nature of raw materials being used and wherein the water absorption in the process has been brought down to within BIS limit.

[0025] In contrast to the existing manufacturing processes, the present invention provides formation of frog or key in the bricks by using hydraulic presses and new moulding system and stacking devices, which is helpful in increasing the grip of one brick with the adjoining brick in the brickwork and wherein the same is also helps in reduction of overall weight by preparing hollow and holed bricks. [0026] In contrast to the existing manufacturing processes, the present invention provides an autoclaved fly ash bricks, wherein the same is manufactured by using up to 92% of fly ash thereby eliminating requirement for the use of sand.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0027] Figure 1 illustrates a process of manufacturing fly ash bricks, in accordance with an embodiment of the present subject matter.

[0028] Figure 2 illustrates a process flow chart of manufacturing fly ash bricks, in accordance with an embodiment of the present subject matter. [0029] It is to be understood that the attached drawings/figures are for purposes of illustrating the concepts of the invention and may not be to scale. DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0030] The following clearly describes the solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. [0031] A detailed description of one or more embodiments of the invention is provided below along with accompanying figures that illustrate the principles of the invention. The invention is described in connection with such embodiments, but the invention is not limited to any embodiment. The invention encompasses numerous alternatives, modifications and equivalents. Numerous specific details are set forth in the following description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims with some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

[0032] According to one aspect of the present invention to provide an autoclaved fly ash bricks wherein the same is manufactured by using selective proportion of ash, sand, lime/sludge and by the pressure in the presses as per the nature of raw materials being used and wherein the water absorption in the process has been brought down to within BIS limit.

[0033] According to another aspect of the present invention to provide an autoclaved fly ash bricks etc., wherein the same is manufactured by using high speed robotic mechanical or hydraulic presses, new moulding system and stacking devices, which provides for having frog on the bricks, wherein said frog or key in the bricks is helpful in increasing the grip of one brick with the adjoining brick in the brickwork and wherein the same also helps in reduction of overall weight by preparing hollow and holed bricks.

[0034] According to another aspect of the present invention to provide autoclaved fly ash bricks etc, wherein the same is used in non-load bearing walls as they are lighter in weight and are useful in reducing the overall weight of the structure.

[0035] According to another aspect of the present invention to provide an autoclaved fly ash bricks, wherein the same is manufactured by using sludge acetylene or oxygen gas plants etc. which is an industrial waste product and a pollutant, has double benefit of preserving lime a limited resource and simultaneously using an industrial pollutant.

[0036] According to another aspect of the present invention to provide autoclaved fly ash bricks etc, wherein used sludge is sludge of acetylene, oxygen gas plants etc.

[0037] According to another aspect of the present invention to provide autoclaved fly ash bricks etc, wherein the same is manufactured by using up to 92% of fly ash thereby eliminating requirement for the use of sand. [0038] According to another aspect of the present invention to provide an autoclaved fly ash bricks, wherein the same is manufactured by using hydraulic presses which reduces the consumption of electricity. [0039] According to another aspect of the present invention to provide an autoclaved fly ash bricks, wherein the process used in the manufacturing is devoid of the reactor and remixing processes thereby reducing both the electricity and time to ½ to 4 hours of the process. [0040] The fly ash bricks manufactured according to the existing invention are usually greyish in colour apart from being able to meet international standards in terms of strength, light weight, super fine finish, insulation properties, firm dimensions, fire protection, sound protection etc. According to the present invention, it is possible to use fly ash as well as pond ash up to 92% in a relatively much shorter duration. Also it is possible to produce fly ash bricks, tiles, curb stones, blocks etc in different colours using suitable colouring material.

[0041] The process according to present invention also enables mass utilisation of fly ash apart from mass production of bricks with perfect quality using smaller space and shorter time duration

[0042] In accordance with one of the embodiment of the present invention, there is provided a process of manufacturing fly ash bricks, wherein the pond ash or fly ash is used up to 92% with or without siliceous sand after mixing with burnt lime powder or hydrated lime power or sludge of acetylene gas, oxygen gas and water. The process is carried out by reacting the mass followed by giving shape to the bricks by high speed robotic mechanical or hydraulic presses and finally cured in autoclaves to produce good quality bricks etc. [0043] Henceforth, embodiments of the present disclosure are explained with the help of exemplary diagrams and one or more examples. However, such exemplary diagrams and examples are provided for the illustration purpose for better understanding of the present disclosure and should not be construed as limitation on scope of the present disclosure.

[0044] Referring now to figure 1 a process of manufacturing fly ash bricks is illustrated in accordance with an embodiment of the present subject matter. As shown in figure 1:

[0045] At step 102: a homogenous mixture is prepared by dosing of fly ash, lime, sludge to mixer and water.

[0046] At step 104: Mix is allowed to stay in reactor for approximately ½ to 4 hours. During this period mass is cured and calcium hydration process is completed. Thereafter, if necessary, second wet mixing of mass is carried out to ensure appropriate moisture content.

[0047] At step 106: the automatic high speed robotic mechanical/hydraulic press is used for shaping of products along with the stacking and automatic insertion in autoclave.

[0048] At step 108: Hardening of semi-products is done in autoclaves at around

200 PSI (13.60 ATM) and around 250 Temperature which are further varied as per requirement. Under the influence of elevated temperature lime and fly ash particulars react producing Calcium Silicate, which binds the grains of sand and/or fly ash forming a hard material of high strength. Steam required for hardening process is provided by a boiler. The Hardening cycles takes about 4 - 5 hours. [0049] At step 110: The mass followed by giving shape to the bricks by high speed press and finally cured in steam shall be autoclaved fly ash bricks.

[0050] Accordingly to a one implementation, fly ash bricks etc. are disclosed. The fly ash bricks etc incudes fly ash or pond ash with or without impurities, up to 92%; lime content between 8-10%; and/or sludge content between 15-25%.

[0051] According to another implementation, fly ash bricks etc are disclosed.

The fly ash bricks etc. includes a fly ash or a pond ash with and without impurities, up to 92%; lime content between 8-10%; and sludge content between 15-25%.

[0052] In an embodiment, the the fly ash includes at least a carbon, an iron, a sulphur, a sulphide, a granulation or any combination thereof, the carbon content is preferably as loss on ignition at 1000 deg C temp, the iron is preferably as a ferric oxide (Fe203 in R203), the sulphur preferably as sulphur dioxide. In one embodiment, the carbon content is preferably up to 7%, the iron is preferably up to 18%, the sulphur preferably up to 0.2%, the sulphide is preferably up to 1.95gm/cucm, and the granulation is preferably up to residue of 5% of 0.06 mm of mesh. [0053] In an embodiment, the fly ash further includes impurities and foreign material, preferably siliceous sand, acquired during the transportation from production to storage and/or during long period of storage.

[0054] In an embodiment, the lime includes contents of active calcium oxide, contents of magnesium oxide, granulation of quicklime (optional), residue of sieve mesh, or any combination thereof, the contents of the active calcium oxide is preferably more than 80%, the contents of magnesium oxide is to be below 2%, the granulation of quicklime (optional) preferably of 0.063 mm up to 0.1%, and the residue of sieve mesh preferably of 0.08 mm up to 80%. [0055] In an embodiment, the sludge includes a sludge of acetylene, oxygen gas plants are preferably up to 15-25 % (depending on nature of sludge including percentage of CaO). [0056] In an embodiment, the fly ash bricks etc further includes one or more frogs or key, wherein the frog or the key helpful in increasing a grip of one fly ash bricks etc with adjoining fly ash brick etc in the brickwork etc and also helps in reduction of overall weight by preparing hollow and holed fly ash bricks etc. [0057] In one implementation, a process of manufacturing fly ash bricks etc is disclosed. The process includes the steps of dosing of a fly ash or a pond ash, lime and sludge to mixer, wherein water is added to make a homogeneous mix and the homogeneous mix is allowed to stay in reactor for at least ½ to 4 hours; shaping the homogeneous mix by high speed robotic mechanical/hydraulic press with stacking and automatic insertion of the semi high strength product (green bricks) in the autoclave; the lime and fly ash or the pond ash particles in presence of water when pressed form semi product of semi high strength (green bricks). Hardening the homogeneous mix shaped in autoclaves at around 200 PSI (13.60 ATM) pressure and at around 250 degree temperature (which can be further varied as per requirement), wherein when the semi-product (the homogeneous mix shaped) is heated, the lime and the fly ash or the pond ash particular react thereby producing calcium silicate, which binds the grains of sand and/or fly ash forming the product.

[0058] In an embodiment, the sludge includes a sludge of acetylene, oxygen gas plants are preferably up to 15-25 % (depending on nature of sludge including percentage of CaO).

[0059] In an embodiment, during stay in reactor the homogeneous mix is cured and calcium hydration process is accomplished. [0060] In an embodiment, further includes second wet mixing, if necessary, of mass to achieve appropriate or required moisture content.

[0061] In an embodiment, a steam required for hardening process is provided by a boiler, the hardening process preferably takes about 4 - 5 hours.

[0062] In an embodiment, the high speed press is a hydraulic press as per requirement.

[0063] Experimental details: Below tables are detailing the various composition and the raw materials used in the manufacturing. However, the below examples are not limited and will be worked on within the scope of the current invention and filed during the complete application.

[0064] FLY ASH: Generally, fly ash is obtained from the boiler of a thermal power plant. It can be dry fly ash obtained directly from the hopper or obtained from the slurry pond, generally having the following specifications :-

- Carbon content as loss on ignition at 1000 deg C temp. - 7% Max.

- Fe203 in R203 (Ferric Oxide) - 18% Max.

- Sulphur as So2 (Sulphur Dioxide) - 0.2% Max

- Sulphide as S - 1.95gm/cucm

- Granulation - Residue 5% max

0.06 mm.mesh Along with impurities and foreign material acquired during the transportation from production to storage and during long period of storage.

[0065] LIME: Quicklime used for production of fly ash bricks etc. should full- fill the following requirements:

Content of active (calcium oxide) - 80% min Content of Magnesium Oxide (mgo) - below 2%

Granulation of quicklime if supplied as - 0.063 mm. max. 0.1%

Powder (Residue of sieve mesh) - 0.08 mm. max. 80%

Sludge of Acetylene, Oxygen gas plants etc. -15-25 % (depending on nature of

Sludge including percentage of CaO)

[0066] EXOPOSITION: RAW MATERIALS:

Fly ash/pond ash with or without foreign material/impurities - upto 92%

Lime - 8 - 10 %

Sludge of Acetylene, Oxygen gas plants etc. - 15— 25 % (depending on nature of Sludge including percentage of CaO)

[0067] OTHER REQUIREMENTS:

Water

Quantity required: 200 - 250 ltr./ΙΟΟΟ kg

Dissolved solids: less than 500 ppm

PH: 6 to 8

Steam: The process needs wet steam at around 200 PSI (13.60 ATM) and around 250 C Temperature for autoclaving of green bricks through boiler having capacity of 5 tons. The Dryness factor for steam should lies between 0.8 to 0.95.

[0068] MANUFACTURING PROCESS: Figure 2 illustrates a process flow chart of manufacturing fly ash bricks etc., in accordance with an embodiment of the present subject matter. The crucial element of the manufacturing is chemical reactions between fly ash particulars and calcium hydroxide. Stages of the manufacturing process are: • A suitable quantity of fly ash or sand and lime and/or sludge is added in the weighing hopper.

• Dosing of fly ash or sand and lime and/or sludge is fed into to mixer by means of a surge hopper. Thereafter a suitable amount of water is added to make a homogeneous mix. Mix is allowed to stay in reactor for approximately ½ to 4 hours. During this period mass is cured and calcium hydration process is completed. Thereafter, if necessary, second wet mixing of mass is carried out to ensure appropriate moisture content.

• Shaping of products with the use of automatic press is then done along with the stacking, automatic insertion in autoclave by way of trolley.

• Hardening of semi-products is done in autoclaves at least around 200 PSI (13.60 ATM) or more and 250°C Temperature. Under the influence of elevated temperature lime and fly ash particles react producing Calcium Silicate, binding the grains of lime, sand and/or fly ash forming a hard material of high strength. Steam required for hardening process is provided by a boiler. The Hardening cycles takes about 4 - 5 hours.

• Upon autoclaving, the finished product is taken out of the autoclave.

• The finished product is supplied either in packed/bulk form by the use of automatic/manual methods as per the requirement..

[0069] In addition to what is disclosed above, the present invention also provides below mentioned advantages:

i. The present invention utilizes selective proportion of ash, sand, lime /sludge for the production of autoclaved fly ash bricks and by the pressure in the presses as per the nature of raw materials being used and wherein the water absorption in the process has been brought down to within BIS limit.

ii. The present invention provides formation of frog or key in the bricks by using hydraulic presses and new moulding system which is helpful in increasing the grip of one brick with the adjoining brick in the brickwork and wherein the same is also helps in reduction of overall weight by preparing hollow and holed bricks.

The present invention provides an autoclaved fly ash bricks, wherein the same is manufactured by using up to 92% of fly ash thereby eliminating requirement for the use of sand.

The present invention by utilizing fly ash converts/gainfully disposes off fly ash into widely used eco-friendly building material. Conventionally, the fly ash is otherwise disposed of by hazardous methods including land and road filling, mixing in agricultural soil, back filling of mines, dumping in ash ponds and ash mounds.

The present invention conserves the top soil which is the major component of red bricks thereby protecting depleting agricultural lands and contributing in food security.

The present invention conserves wood, coal etc. which is used as major raw material for red bricks.

The present invention conserves non-renewable resources like sand, gypsum, cement and lime.

The present invention provides better quality building material having higher compressive strength, reduced water absorption, lighter in weight, uniform and smooth shape and sizes in various colours, higher sound absorption, reduced thermal conductivity and nil efflorescence.

The present invention provides uniform and smooth shape and sizes, reduces the quantity of cement mortar required for brickwork and plaster (plastering can even be avoided).

The present invention provides capacity to produce bulk quantity throughout the year using minimum space.

The present invention reclaims the prime land occupied for dumping fly ash from the ash mounds. [0070] Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.

[0071] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[0072] Although implementations for autoclaved fly ash bricks etc. and method of manufacturing the same have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations of the autoclaved fly ash bricks etc. and method of manufacturing the same.

Claims

WE CLAIM:

1. Autoclaved fly ash bricks etc. characterized in that comprising:

a fly ash or a pond ash with impurities up to 92%;

a lime content between 8-10%; and

a sludge content between 15-25%.

2. Autoclaved fly ash bricks etc. characterized in that comprising:

a fly ash or a pond ash without impurities up to 92%;

a lime content between 8-10%; and

a sludge content between 15-25%.

3. The fly ash bricks etc. as claimed in claim 1 and claim 2, wherein the fly ash includes at least a carbon, an iron, a sulphur, a sulphide, a granulation or any combination thereof, the carbon content is preferably 7% as loss on ignition at 1000 deg C temp, the iron is preferably as a ferric oxide (Fe203 in R203), the sulphur preferably as sulphur dioxide.

4. The fly ash bricks etc. as claimed in claim 3, wherein the carbon content is preferably up to 7%, the iron is preferably up to 18%, the sulphur preferably up to 0.2%, the sulphide is preferably up to 1.95 gm/cucm, and the granulation is preferably up to residue of 5% of 0.06 mm of mesh.

5. The fly ash bricks etc. as claimed in claim 2, wherein the fly ash includes impurities and foreign material, preferably siliceous sand, acquired during the transportation from production to storage and/or during long period of storage.

6. The fly ash bricks etc. as claimed in claim 1 and claim 2, wherein the lime includes contents of active calcium oxide, contents of magnesium oxide, granulation of quicklime (optional), residue of sieve mesh, or any combination thereof, the contents of the active calcium oxide is preferably more than 80%, the contents of magnesium oxide is to be below 2%, the granulation of quicklime (optional) preferably of 0.063 mm up to 0.1%, and the residue of sieve mesh preferably of 0.08 mm up to 80%.

7. The fly ash bricks etc. as claimed in claim 1 and claim 2, wherein the sludge includes a sludge of acetylene, oxygen gas plants are preferably up to 15-25 % (depending on nature of sludge including percentage of CaO).

8. The fly ash bricks etc. as claimed in claim 1 and claim 2, further comprising: one or more frogs or key, wherein the frog or the key helpful in increasing a grip of one fly ash bricks etc. with adjoining fly ash brick etc. in the brickwork etc. and also helps in reduction of overall weight by preparing hollow and holed fly ash bricks etc.

9. A process of manufacturing fly ash bricks etc. characterized in that comprising the steps of:-

• Dosing of a fly ash or a pond ash, lime and sludge to mixer, wherein water is added to make a homogeneous mix and the homogeneous mix is allowed to stay in reactor for at least ½ to 4 hours;

• Shaping the homogeneous mix of the lime sand/fly ash/pond ash in presence of water is pressed by high speed robotic mechanical/hydraulic press forming semi product of semi high strength (green bricks), and its stacking and automatic insertion in the autoclave ;

• Hardening the homogeneous mix shaped in autoclaves at around 200 PSI (13.60 ATM) and at around 250 degree temperature which are further varied as per requirement to form the finished product, wherein when the semi-product (the homogeneous mix shaped) is heated and the lime, sand and/or the fly ash or pond ash particles react thereby producing calcium silicate, which binding the grains of sand and/or fly ash forming the product ;

• Supply, by packing in pellets or in bulk form by the use of automatic/manual methods as per the requirement.

10. The process as claimed in claim 9, wherein the sludge includes a sludge of acetylene, oxygen gas plants are preferably up to 15-25 % (depending on nature of sludge including percentage of CaO).

11. The process as clamed in claim 9 further comprising, reducing the water absorption in the process and thereby bringing down to within BIS limit.

12. The process as claimed in claim 9, wherein during stay in reactor the homogeneous mix is cured and calcium hydration process is accomplished.

13. The process as claimed in claim 9 further comprising: second wet mixing, if necessary, of mass to achieve appropriate or required moisture content.

14. The process as claimed in claim 9, wherein the high speed press is a high speed robotic mechanical/hydraulic press.

15. The process as claimed in claim 9, wherein automatic stacking and insertion in the autoclave is the automatic stacking and insertion of the semi product of semi high strength (green bricks).

16. The process as claimed in claim 9, wherein a steam required for hardening process is provided by a boiler, the hardening process preferably takes about 4 - 5 hours.

17. The process as claimed in claim 9, wherein automatic packing in pellets is the automatic packing in pellets of the finished product.