DESC:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A SYSTEM FOR THE SEPARATION OF ALKALI FROM THE BLAST FURNACE POT DUST WITH UTILIZATION OF WASTE FLUE GAS.



2 APPLICANT (S)

Name : JSW STEEL LIMITED;

Nationality : An Indian Company.

Address : Dolvi Works, Geetapuram, Dolvi, Taluka Pen, Dist. Raigad, Maharashtra-402107, India; Having the Registered Office at
JSW CENTRE,BANDRA KURLA COMPLEX,BANDRA(EAST), MUMBAI-400051, STATE OF MAHARASHTRA, INDIA.




3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a system for separation of alkali from blast furnace pot dust. More particularly, the present invention provides a reaction system comprising a reactor for the leaching of alkali from pot dust using the waste flue gas in a batch process. The system injects the hot flue gas through a vertical connector mounted on the top of the reactor vessel. It would not only transfer heat to the leaching media but also improve the agitation of the system by continuous purging of flue gas to the system. The system performs a process scheme that includes froth floatation, followed by water leaching and filtration, for recovering carbon as a carbon rich froth, subjecting non froth to water leaching and filtering the leach solution to obtain solid residue substantially free of alkali and significantly reducing sulfur and chlorine level to make it suitable for use in steel plant operations, such as pellet, briquette or sinter making process, while the filtrate solution is evaporated and crystallized for getting alkaline salts as a separate product and recycling water after condensation.
BACKGROUND OF THE INVENTION
India stands as one of the foremost contributors to global steel production, producing approximately 130 million metric tons in 2023, with a consistent upward trend. A significant portion of India's steel output is derived through the blast furnace route, resulting in the generation of substantial fine dust particles, known as flue dust or pot dust. Typically, this pot dust amounts to around 20 kg per ton of steel and contains iron and carbon values, necessitating its recirculation into mainstream iron-making processes for both economic and environmental considerations. However, the presence of undesirable elements such as alkali, lead, and zinc restricts its utilization in the production of iron ore pellets, sinter, or briquettes.
Addressing this issue, a patent titled "A process for recovery of carbon and removal of alkali from blast furnace pot dust" has been filed with application number 202321075405 on 4thNovember, 2023. The patented process proposes an integrated approach involving froth flotation, water leaching, and filtration techniques. This process separates a carbon-rich product as froth from the froth flotation unit.On the other hand, an alkali-free solid residue is obtained from the filtration unit, which is suitable for recirculation in pellet/sinter/briquetting units. The leach liquor, separated as filtrate, undergoes evaporation crystallization to produce an alkali-rich residue, primarily consisting of about 70% potassium chloride (KCl). Later, the evaporated steam is subsequently condensed for recirculation in the leaching process.
The present invention is in continuation with applicant’s co-pending patent application(Application number 202321075405), which is directed towards the enhancing the process efficacy. The present innovation provides a system that introduces an innovative experimental condition, which involves utilizing waste flue gas generated from various units of an integrated steel plant to elevate the temperature during both the leaching and evaporation crystallization processes. Notably, the leaching process is carried out at a temperature ranging from 900 to 950C, which can effectively be attained by the waste flue gas.
The gradual depletion of high grade raw materials and increasing market demand necessitated the utilization of lean grade raw materials for the primary steel making purpose. These subgrade raw materials are often associated with various impurities like alkali, zinc, lead and various other heavy metals. In addition, such impurities are often found in the form of complex silicates, carbonates and oxides, which get decomposed and reduced to elemental vapors at high temperature while treated in the blast furnace. It has been observed that the particles emitting through the blast furnace off gas associate with such vapors and thus these off gas dusts carry substantial amount of alkali and zinc. Studies indicate that the production of one ton of raw steel leads to the generation of approximately 20 kg of flue dust. Consequently, the annual production of blast furnace flue dust in India amounts to around 2.4 million tons.
Presently, steel industries employ dry de-dusting systems that consist of two-stage air classifiers to collect these dusts from the BF off gas. The initial air classifier is designed to capture coarse particles, while the subsequent one predominantly captures fine to ultrafine particles. This specific category of secondary dust is commonly known as "pot dust".Pot dust comprises of significant amount of iron, carbon, calcium oxide, magnesium oxide values apart from alkali, zinc and lead, making it imperative for recirculation into the mainstream of iron-making processes. However, the presence of detrimental components like alkali, lead, and zinc imposes restrictions on its recirculation due to their adverse impacts on blast furnace operations.
Hydrometallurgical route has been found of prominent application while separating alkali as well as various other heavy metals from BF dust. Previously, a patent titled “A process for recovery of carbon and removal of alkali from blast furnace pot dust" has been filed by the same applicant with application number 202321075405 on 4thNovember, 2023. The present innovation is in continuation with the previous patent providing a system for implementing the said process claimed in earlier patent, while addressing the energy requirement for leaching as well as evaporation crystallization processes proposed in the previous patents.
Though a few patents are available addressing the leaching of BF dust via various routes, none of them encapsulates the inventive concept of using waste flue gas for increasing the temperature of leaching reactor and in subsequent evaporation process.

The patent registered under number CN103966421A, titled "A method for comprehensive recycling of iron and steel metallurgical waste," outlines a strategy for reducing alkali content in various solid waste materials generated by the iron and steel industries. This method employs water-based leaching followed by a subsequent crystallization procedure. The resulting leachate undergoes treatment with Na2S and K2SO4 to eliminate impurities. Further steps involve concentration through evaporation and crystallization to recover KCl as a secondary product. To achieve a product enriched with Fe values, a magnetic separation technique is applied. The non-magnetic fraction is then subjected to roasting at a temperature of 1200°C to obtain values of directly reduced iron. Additionally, the process encompasses the extraction of metallic zinc from zinc-containing fumes through leaching, purification, and electro-winning methodologies.
The patent registered as CN103435073B, titled "Method for producing potassium chloride using blast furnace dust of iron and steel enterprises," presents a method for obtaining KCl from the residual material of blast furnaces. The mentioned patent focuses on the treatment ofvarious solid wastes and extracting a valuable secondary product. The methodology involves a two-stage process, encompassing water leaching, followed by filtration and evaporation crystallization. Prior to the evaporation crystallization stage, precipitating agents such as sodium carbonate, sodium sulfate, and potassium sulfate are utilized to eliminate impurities.
The patent with number CN105712380A, titled "System and method for production of potassium chloride sintering flue gas precipitator dust," reveals a technique for extracting potassium chloride salt through a series of processes involving water leaching, precipitation, and evaporation crystallization. In this method, a concentrated KCl solution serves as the precipitating agent, and the solution undergoes heating within the temperature range of 85°C to 95°C to achieve super-saturation. Following this, solid crystals are separated from the solution through filtration, yielding KCl crystals distinguished by their high purity levels.
Patent CN113403480A, titled "Recovery method and application of high alkali high zinc blast furnace gas ash," details a process for removing alkali and zinc from blast furnace gas ash, along with their respective methods. The removal of alkali from the gas ash is carried out through a multi-stage water leaching process, after which the extracted alkali is processed via evaporation crystallization. The ash, now free from alkali, is then treated using a carbothermic reduction process, leading to the creation of secondary ZnO powder. This powder undergoes leaching with a reagent containing ammonia. Subsequently, the solution with the zinc-ammonia complex is treated through ammonia-evaporation crystallization, resulting in the formation of zinc carbonate crystals.
OBJECTS OF THE INVENTION
The basic object of the present invention is to provide a system for alkali removal from BF pot dust comprising a leaching reactor and evaporation system with the energy input to the leaching and evaporation process from waste flue gas available from various units of an integrated steel plant.
A further object of the present invention is directed to the system that injects the hot flue gas through a vertical connector mounted on the top of the leaching reactor vessel, not only transfer heat to the leaching media but also help pre-conditioning of the feed and improve the agitation of the system by continuous purging of flue gas to the system.
A still further object of the invention is to utilize the waste flue gas including BF off gas having temperature in the range of 150-2000C to maintain the temperature of the leaching system as well as in evaporating the filtrate to obtain the solid residue with high alkali content.
A still further object of the present invention is directed to the system that helps generating a solid residue substantially free of alkali and significantly reducing sulfur and chlorine level to make it suitable for use in steel plant operations, such as pellet, briquette or sinter making process, while the filtrate solution is evaporated and crystallized for getting alkaline salts as a separate product.
A still further object of the invention is to recycling of evaporated water after condensation.
SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to a system for waste flue gas utilization for separation of alkali from blast furnace pot dust comprising :

a column floatation unit for separation of carbon bearing hydrophobic particles from pot dust into a separable carbon rich froth and a non-froth slurry discharge;

a non-froth slurry discharge collecting tank for storing the non-froth slurry discharge from bottom of the column flotation unit ;

a leaching reactor unit for leaching of alkali and generate leached solution from said non-froth slurry discharge supplied from said non-froth slurry discharge collecting tank;

a filtration unit including a filter press for separation of the solid solute from leach liquor from said leached solution ;

an evaporator unit for evaporating the leach liquor and separating solid alkali from water ;

a compressor unit for storing and circulating hot flue gas to said leaching reactor unit and said evaporator unit provided with jacketed outer wall having inlet and outlet for the said hot flue gas thereby facilitating hot flue gas utilization for controlling of the heat required in said leaching and evaporation process in the leaching reactor and evaporator unit respectively.

A further aspect of the present invention is directed to said system wherein said compressor unit stores hot flue gas having a temperature in the range of 1500 to 2000 C which is supplied to said jacketed outer wall of said leaching reactor and said evaporator unit through respective pre-heater units with the pre heated hot flue gases being supplied to the respective jacketed outer wall through inlet into said jacketed wall portions and outlet from said jacketed wall portions for collection in a gas stack.

A still further aspect of the present invention is directed to said system wherein a pump means is used for supply of the (i) non-froth slurry from the collecting tank to the leaching reactor (ii) said discharges slurry from the leaching reactor to the filtration unit and (iii) pumping of leach liquor to the evaporator unit.

A still further aspect of the present invention is directed to said system wherein said leaching reactor unit comprises:

motorized agitator for intensively conditions the slurry for the selective dissolution of alkali;
a feed inlet for introducing the slurry to the leaching reactor ;
a steam discharge point for discharge of steam generated in reactor ;
a double jacketed wall having an inner part providing the leaching chamber, while, the outer chamber providing for passage of the hot flue gas to increase the temperature of the pulp, said jacketed outer chamber having a hot gas inlet for entering the hot flue gas through this chamber and by the principle of conduction and convection the hot flue gas provide for increase the temperature of the pulp and a hot gas outlet for discharge of the hot flue gas.

A still further aspect of the present invention is directed to said system wherein said jacketed outer chamber include a spiral path whereby the hot gas entering to the system have the maximum retention time and facilitate the maximum heat transfer.

A still further aspect of the present invention is directed to said system wherein said evaporator unit comprises :

a leach liquor inlet for pumping in the leach liquor, separated from the filter press into the evaporator ;

a steam outlet at the top section of the evaporator through which hot water steam can travel to a condenser;
a double jacketed wall wherein inner part houses the leaching liquor, while, the outer chamber pass hot flue gas to evaporate the liquor , wherein a Flue gas inlet provides for entry of the Hot flue gas (>150°C) into the evaporator unit which is regulated by a high-temperature resistant valve whereby and an outlet for Flue Gas through which the hot gas is discharged ;

a discharge point outlet through which the alkali paste (P3) is discharged and subjected to a screw pump.

Another aspect of the present invention is directed to said system wherein said jacketed wall chamber pathway for the hot flue gas include a spiral path whereby the hot gas entering to the system have the maximum retention time and facilitate the maximum heat transfer.

Yet another aspect of the present invention is directed to said system wherein the filter press generated solid reside output product (P2) is recirculated to any of pellets, sinter and briquette making units and wherein the alkali paste product (P3) is sources as a source of alkali to any one of cement plants, fertilizer production, and various other applications.

A further aspect of the present invention is directed to said system as claimed in anyone of claims 1 to 8 comprising condenser unit for flow of cold water along the steam outlet channel of the evaporator unit for condensing of the steam which is operatively connected to a water collecting tank for storing water for re-use ; slurry outlet at the bottom of the evaporator operatively connected to slurry screw pump wherein the saturated pulp with alkali paste discharged from evaporator is pumped therethrough to a spray drier to remove residual moisture content.

A still further aspect of the present invention is directed to said system wherein the hot flue gas after utilization is collected and stored in a gas stack.
The above and other aspects and advantages of the present invention are described hereunder in greater details with reference to following accompanying non limiting illustrative drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 shows the schematic diagram of the proposed system for the separation of alkali from the BF pot dust indicating flow diagram for the process.
Fig. 2: shows a Cross-section view of the leaching reactor for the said process.
Fig. 3: shows the sectional view of Evaporator for leached liquor.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
The present invention is directed to provide a system for separation of alakali from blast furnace pot dust comprising a reactor for the leaching of alkali from pot dust using the waste flue gas in a batch process.
The system has provision to inject the hot flue gas through a vertical connector mounted on the top of the leaching reactor vessel. It would not only transfer heat to the leaching media but also help pre-conditioning of the feed and improve the agitation of the system by continuous purging of flue gas to the system.
In the system, the alakali removal process from pot dust is implemented maintaining following parameters to ensure to incorporate hot flue gas for the leaching purpose:
i. The temperature of the flue gas needs to be in the range of 150-2000C.
ii. The flow rate of the gas should be in the desired range.
iii. A pre-conditioning time of 5-10 minutes needs to be maintained in order to achieve the desired temperature before adding the pot dust sample in the reactor.
The applicants observed that the flow rate and pre-conditioning time of this process is dependent on the total amount of sample treated and on the volume of the reactor vessel. Thus, these parameters need to be evaluated prior to the leaching process to control the reaction with a high degree of accuracy.
The system having apparatuses to perform a process scheme that includes froth floatation, followed by water leaching and filtration, for recovering carbon as a carbon rich froth, subjecting non froth to water leaching and filtering the leach solution to obtain solid residue substantially free of alkali and significantly reducing sulfur and chlorine level to make it suitable for use in steel plant operations, such as pellet, briquette or sinter making process, while the filtrate solution is evaporated and crystallized for getting alkaline salts as a separate product and recycling water after condensation.
Accompanying Fig. 1 shows the schematic of system set-up of the proposed scheme for the separation of alkali from the BF pot dust. The scheme includes froth floatation followed by water leaching and filtration for recovering carbon as a carbon rich froth, subjecting non froth to water leaching and filtering the leach solution to obtain solid residue substantially free of alkali and significantly reducing sulfur and chlorine level to make it suitable for use in steel plant operations, such as pellet, briquette or sinter making process, while the filtrate solution is evaporated and crystallized for getting alkaline salts as a separate product and recycling water after condensation. The obtained alkali can be a separate marketable byproduct for the variety of application including but not limited to the fertilizer, cement, chemical reagents manufacturing etc. In addition, the separated carbon particles could be consumed either in the same pelletization process through a different route or in various other iron or steel making applications. Notably, reducing alkali input by 1 kg/ton of hot metal in blast furnace reduces the coke rate by approx. 10 kg/ton of hot metal which reduces 12 kg/ton CO2 emission.
Referring to Figure 1, the preferred embodiment of the proposed process incorporates several units, as illustrated. The unit details are outlined below:
A. Compressor: This unit is responsible for storing and circulating hot flue gas to the leaching reactor (unit 5) and evaporator (unit 9) in a controlled manner. The compressor specifically carries waste flue gas (CO: 0.8-1.3%, CO2: 25-35%, H2: 0-0.1%, O2: 0.1-0.5%, N2: 60-70%) with a temperature in the range of 150-2000C. The daily generation of the waste flue gas is about 600000-650000 m3/day.
B. Column flotation: This unit is employed for the separation of carbon-bearing hydrophobic particles from pot dust using various surfactants. The carbon-rich froth, identified as product 1 (P1), is separated from the top of the column, while the non-froth is discharged from the bottom.
C. Collecting tank: The collecting tank is designed to store the non-froth slurry discharged from the flotation column.
D. Pump-1: Used for pumping the non-froth slurry from the collecting tank (unit 3) to the leaching reactor.
E. Preheater 1: This unit is used to pre-heat the slurry to 50-600C entering to the leaching reactor for better commencing of reaction.
F. Leaching reactor: This unit is intended to do the leaching of alkali. A cross-sectional view of the reactor is shown in Fig. 2, where different parts are designated numerically.
1. Motorized agitator: Intensively conditions the slurry for the selective dissolution of alkali.
2. Feed inlet: the slurry is introduced to the leaching reactor through this point.
3. Steam discharge point: The steam generated in reactor is discharged through this point.
4. Double jacketed wall: A jacketed design has been considered for the present application. The inner part will have the leaching chamber, while, the outer chamber would pass hot gas to increase the temperature of the pulp.
5. Hot gas outlet: The hot gas used in jacketed reactor is discharged through these points.
6. Hot gas inlet: The hot flue gas would enter to the reactor through this chamber and by the principle of conduction and convection the hot gas would increase the temperature of the pulp.
G. Pump-2: Used to pump the discharged slurry from the leaching reactor to the filtration unit.
H. Filter press: The filter press is used to separate the solid solute from the leached solution. The solid residue (P2) obtained from this unit has a substantial reduction in the alkali content and can be recirculated to pellet/sinter/briquette making units.
I. Pump-3: Potentially used for pumping the leach liquor to the evaporator for downstream operations.
J. Preheater 2: This unit is used to pre-heat the slurry to 50-600C entering to the evaporator in order to avoid the partial crystallization of dissolved salt.
K. Evaporator: This unit is dedicated to evaporating the leach liquor, facilitating the separation of solid alkali from water in a batch-type process. Fig. 3 presents a cross-sectional view with parts designated numerically.
1. Hot flue gas outlet: The waste flue gas with temperature ranging between 150-200°C is injected into the evaporator through this point, regulated by a high-temperature resistant valve. The hot gas is discharged trough this point.
2. Steam outlet: The top section of the evaporator features a conical outlet through which hot water steam can travel to the condenser.
3. Leach liquor inlet: The leach liquor, separated from the filter press, is pumped into the evaporator through this inlet.
7. Double jacketed wall: A jacketed design has been considered for the present application. The inner part will have the leaching liquor, while, the outer chamber would pass hot gas to evaporate the liquor.
4. Discharge point: The solid alkali residue (P3) is discharged from this outlet and subjected to a screw pump. This product (P3) can be utilized as a source of alkali for cement plants, fertilizer production, and various other applications.
5. Flue gas inlet: Hot flue gas (150-200°C) is injected into the evaporator through this point, regulated by a high-temperature resistant valve.
L. Condenser: This unit employs a flow of cold water along the steam outlet channel of the evaporator (K-2), which would help in condensing the steam.
M. Water collecting tank: Condensed water is stored in this chamber for reuse in further leaching processes or other applications.
N. Slurry screw pump: The saturated pulp with alkali residues discharged from the evaporator (K-4) is pumped through this unit to the spray dryer in order to remove the residual moisture from the alkali metal precipitate (majorly KCl).
O. Spray dryer: A spray dryer is used to remove the residual moisture from the alkali metal precipitate to obtain the completely moisture free alkali metal precipitate (majorly KCl).
P. Gas stack: The gas exerted from different units are collected and stored here.

It is thus possible by way of the present invention to provide a system for the separation procedure of alkali from the blast furnace pot dust comprising different unit operations, such as froth flotation, alkali leaching, filtration and evaporation techniques is proposed. The alkali leaching and evaporation techniques are heat energy intensive processes, where the proposed process details the design parameters and quantification of energy requirement for the said process. No external heat supply source is required. The utilization of waste flue gas for the separation of alkali from the blast furnace pot dust specifically utilizes the waste flue gas with temperature 150-200°C to maintain the temperature of 85-950C in the leaching reactor generated at various units of an integrated steel plant.
The utilization of waste flue gas apart from the separation of alkali metals from the blast furnace pot dust, also specifically used to evaporate water from the solution and can obtain the solid alkali metal residue. Evaporated water after condensation is recirculated in the leaching as well as in other applications. The waste flue gas after utilization through the system for leaching and evaporation steps, the temperature of the waste gas reduces to 70-800C, which is well under the permissible limit specified in discharge gas norm.
,CLAIMS:We Claim:

1. A system for waste flue gas utilization for separation of alkali from blast furnace pot dust comprising :

a column floatation unit (B) for separation of carbon bearing hydrophobic particles from pot dust into a separable carbon rich froth and a non-froth slurry discharge;

a non-froth slurry discharge collecting tank(C) for storing the non-froth slurry discharge from bottom of the column flotation unit ;

a leaching reactor unit(F) for leaching of alkali and generate leached solution from said non-froth slurry discharge supplied from said non-froth slurry discharge collecting tank;

a filtration unit including a filter press(H) for separation of the solid solute from leach liquor from said leached solution ;

an evaporator unit(K) for evaporating the leach liquor and separating solid alkali from water ;

a compressor unit(A) for storing and circulating hot flue gas to said leaching reactor unit and said evaporator unit provided with jacketed outer wall having inlet and outlet for the said hot flue gas thereby facilitating hot flue gas utilization for controlling of the heat required in said leaching and evaporation process in the leaching reactor and evaporator unit respectively;
a condenser unit(L) that employs a flow of cold water along the steam outlet channel of the evaporator, which helps in condensing the steam and storing the condensed water in a water collecting tank(M) for reuse in further leaching processes or other applications.
2. The system as claimed in claim 1 wherein said compressor unit stores hot flue gas having a temperature in the range of 1500 to 2000 C which is supplied to said jacketed outer wall of said leaching reactor and said evaporator unit through respective pre-heater units with the pre heated hot flue gases being supplied to the respective jacketed outer wall through inlet into said jacketed wall portions and outlet from said jacketed wall portions for collection in a gas stack.
3. The system as claimed in anyone of claims 1 or 2 wherein a pump means is used for supply of the (i) non-froth slurry from the collecting tank to the leaching reactor (ii) said discharges slurry from the leaching reactor to the filtration unit and (iii) pumping of leach liquor to the evaporator unit.
4. The system as claimed in anyone of claims 1 to 3 wherein said leaching reactor unit comprises:

motorized agitator for intensively conditions the slurry for the selective dissolution of alkali;
a feed inlet for introducing the slurry to the leaching reactor ;
a steam discharge point for discharge of steam generated in reactor ;
a double jacketed wall having an inner part providing the leaching chamber, while, the outer chamber providing for passage of the hot flue gas to increase the temperature of the pulp, said jacketed outer chamber having a hot gas inlet for entering the hot flue gas through this chamber and by the principle of conduction and convection the hot flue gas provide for increase the temperature of the pulp and a hot gas outlet for discharge of the hot flue gas.
5. The system as claimed in claim 4 jacketed outer chamber include a spiral path whereby the hot gas entering to the system have the maximum retention time and facilitate the maximum heat transfer.
6. The system as claimed in anyone of claims 1 to 5 wherein said evaporator unit comprises :

a leach liquor inlet for pumping in the leach liquor, separated from the filter press into the evaporator ;

a steam outlet at the top section of the evaporator through which hot water steam can travel to a condenser;
a double jacketed wall wherein inner part houses the leaching liquor, while, the outer chamber pass hot flue gas to evaporate the liquor , wherein a Flue gas inlet provides for entry of the Hot flue gas (>150°C) into the evaporator unit which is regulated by a high-temperature resistant valve whereby and an outlet for Flue Gas through which the hot gas is discharged ;

a discharge point outlet through which the alkali paste (P3) is discharged and subjected to a screw pump.

7. The system as claimed in claim 6 wherein said jacketed wall chamber pathway for the hot flue gas include a spiral path whereby the hot gas entering to the system have the maximum retention time and facilitate the maximum heat transfer.
8. The system as claimed in anyone of claims 1 to 7 wherein the filter press generated solid reside output product (P2) is recirculated to any of pellets, sinter and briquette making units and wherein the alkali paste product (P3) is sources as a source of alkali to any one of cement plants, fertilizer production, and various other applications.
9. The system as claimed in anyone of claims 1 to 8 comprising condenser unit for flow of cold water along the steam outlet channel of the evaporator unit for condensing of the steam which is operatively connected to a water collecting tank for storing water for re-use ; slurry outlet at the bottom of the evaporator operatively connected to slurry screw pump wherein the saturated pulp with alkali paste discharged from evaporator is pumped therethrough to a spray drier to remove residual moisture content.
10. The system as claimed in anyone of claims 1 to 9 wherein the hot flue gas after utilization is collected and stored in a gas stack.
Dated this the 17th day of February, 2025
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199