FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
A DRY QUENCHING PROCESS FOR WHITE CEMENT CLINKER
MANUFACTURING
UltraTech Cement Limited
an Indian Company, of "B" Wing, 2nd floor, Ahura Centre, Mahakali Caves Road, Andheri (East), Mumbai 400 093, Maharashtra, India.
Inventors:
1. KAPOOR HANS RAJ
2. JAIN RAMESH CHAND
3. CHHAPERWAL SUNIL
4. VYAS INDER RAJ
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE
PERFORMED

FIELD OF THE DISCLOSURE
The present disclosure relates to a process for manufacturing white cement clinker. Particularly, the present disclosure relates to a dry quenching process for manufacturing white cement clinker.
BACKGROUND;
The conventional manufacturing process for white cement (10), as shown in Figure 1, involves crushing of the raw materials (12) primarily comprising a mixture of limestone (or calcareous material) and clay, typically kaolin (or argillaceous material) in a crusher. The crushed mixture is further sent to a raw mill for grinding (14). The fine mixture primarily containing limestone and kaolin is then calcined at a temperature of 1500deg C - 1550 deg C in a rotary kiln (16) to chemically fuse the raw materials and produce a white cement clinker. The resulting white cement clinker thus formed in the rotary kiln (16) is to be quenched with water to prevent the re-oxidation of the iron and thus maintain the whiteness of the cement clinker. The quenching process is carried out by passing the cement clinker through a chamber (18) of a decoloriser/dryer/quencher, as shown in Figure 1, wherein the clinker temperature is rapidly lowered from 1200 deg C to below 600 deg C to obtain white cement clinker.
Referring to Figure lof the accompanying drawings, red hot clinkers from the rotary kiln (16) having a temperature of above 1200 deg C are discharged in a chamber (18) where water (20) is introduced for quenching. After wet quenching, the clinker is dried and water is converted in to superheated steam, thereby producing dry white cement clinker having temperature below 200 deg C and a mixture of super-heated steam along with flue gases (22) is discharged. The super-heated steam thus discharged has a temperature between 200 - 400 deg C and is laden with dust and gases. The exhaust gas stream comprising 55% steam and 45% air is passed through cyclone separators, an electrostatic precipitator (ESP) or bag house to remove the dust particles and then released into the atmosphere. The temperature of the exhaust gas

stream leaving the cyclone separator is in the range of 160 - 220 deg C. Referring to Figure 1, the white cement clinker from the decoloriser/dryer, after a drying stage, is ground to cement (24).
The water utilized in the conventional wet quenching process for cooling the red hot white cement clinker, as disclosed in Figure 1, extracts heat from the white cement clinker and is converted into steam. Further, dust particles and exhaust gases are emitted during the grinding, calcining, quenching and drying processes of the cement clinker.. The steam along with the exhaust gases are discharged into the atmosphere after being passed through a cyclone separator for removal of dust particles and through an electrostatic precipitator / a bag house for removal of particulate matter. Further, a large quantity of water is required in the wet quenching process.
Hence, there is felt a need for a white cement quenching process that overcomes the drawbacks of the conventional process such as usage of large quantity of water and wastage of energy.
OBJECT:
Some of the objects of the system of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a dry quenching process for manufacturing white cement clinker.
Another object of the present disclosure is to provide a process for manufacturing white cement clinker which eliminates usage of water for quenching.
Yet another object of the present disclosure is to provide a process for manufacturing white cement clinker which conserves energy.

An added object of the present disclosure is to provide a process for manufacturing white cement clinker which is economical.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
In accordance with the present disclosure there is provided a dry quenching process for manufacturing hot cement clinker, the process comprises the steps of: feeding hot cement clinkers to a chamber; and
quenching the hot cement clinker in the chamber to produce white cement clinker by injecting a non-oxidizing gas into the chamber through
• a first inlet for injecting the non-oxidizing gas along the inflow direction of the hot cement clinker, and
• a second inlet for injecting the non-oxidizing gas in a direction opposite the inflow direction of the hot cement clinker; and
recovering sensible heat from the gases exiting the chamber.
In one embodiment, the step of recovering sensible heat is followed by the step of recirculating the gases through the chamber.
The non-oxidizing gas can be selected from the group of gases consisting of carbon-dioxide, nitrogen, argon, neon, helium, krypton, xenon and radon etc. •
The hot cement clinkers can be at a temperature in the range of 1000°C to 1300°C.
Each of the inlets may be defined by at least one entrance.

The flow of the non-oxidizing gas within the chamber may be regulated/ actuated by controlling the flow of the non-oxidizing gas through the first inlet and the second inlet.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES:
The dry quenching process for quenching hot cement clinker, of the present disclosure will now be described with the help of accompanying drawings, in which:
Figure 1 illustrates a schematic diagram of the conventional process for manufacturing white cement;
Figure 2 illustrates a schematic diagram of the white cement manufacturing process in accordance with the present disclosure; and
DETAILED DESCRIPTION
Figure 1 illustrates the wet quenching process (10) conventionally used for quenching of hot cement clinkers wherein superheated steam is utilized in quenching of the hot cement clinkers.
The present disclosure of dry quenching process for quenching hot cement clinker stems from the observation that the conventional quenching process is plagued with the drawbacks such as wastage of energy and water which are inevitable due to usage of steam.
The use of inert gas in the dry quenching process for manufacturing white cement clinker is disclosed in co-pending Indian Patent Application No. 2695/MUM/2009.
A system and a method of the present disclosure will now be described with reference to the embodiments which do not limit the scope and ambit of the disclosure.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
Figure 2 illustrates a process for manufacturing white cement clinker using a dry quenching process (100) in accordance with the present disclosure and is reference by the numeral 100. The hot white cement clinker from a rotary kiln (102) is quenched in a chamber (104). The chamber (104) has a shape typically elliptical, circular or polygonal. The chamber (104) may or may not be actuated by any form of energy.
A non-oxidizing gas is introduced into the chamber (104) from a gas containing unit (106). The non-oxidizing gas may be any one or a mixture of carbon dioxide, nitrogen, argon, neon, helium, krypton, xenon, radon and the like. The non-oxidizing gas is introduced into the chamber (104) via a first inlet (105a) and a second inlet (105b). The non-oxidizing gas is introduced through the first inlet (105a) along the inflow direction of the hot cement clinker. On the other hand, the non-oxidizing gas is introduced into the chamber (104) through the second inlet (105b) in a direction opposite the inflow direction of the hot cement clinker. The first inlet (105a) and the second inlet (105b) are defined by at least one entrance. The direction of flow of the non-oxidizing gas within the chamber (104) is regulated/actuated by controlling the flow of the non-oxidizing gas through the first inlet (105a) and the second inlet (105b) by means of a control mechanism such as valves (107).
The hot white cement clinkers from the rotary kiln (102) having a temperature in the range of 1000 °C to a temperature greater than 1300 °C are fed into the chamber (104) wherein the hot white cement clinkers are dry quenched by passing the non-

oxidizing gas over the hot white cement clinkers. The non-oxidizing gas absorbs heat from the hot white cement clinkers, thereby quenching the hot white cement clinkers and reducing the temperature of the hot white cement clinkers below 200 °C.
The non-oxidizing gas circulated through the chamber (104), extracts heat from the hot white cement clinker, thereby increasing the temperature of the Non-Oxidising gas to the range of 500 °C to 900 °C. As illustrated in Figure 2, heated exhaust gases exit the chamber (104). The sensible heat of the heated gases, exiting the chamber (104) is extracted through a waste heat recovery system (110) and/or is released into the atmosphere (108) after removal of dust in a dust removal system. The sensible heat recovered from the inert gas is utilized for further usage in an intended process (120), for example, generation of electricity using a waste heat boiler. The extraction of the sensible heat improves the energy efficiency of the clinkerisation process utilizing the dry quenching process of the present disclosure. The gas flow rate for injection is in the range of 1 Nm3/Kg to 26 Nm3/Kg of clinker. The direction of flow of the non-oxidizing gas is regulated depending on the temperature of hot white cement clinker and gas in the chamber (104). The flow of the non-oxidizing gas is either along the direction of flow of the cement clinker or against the direction of flow of the cement clinker.
The non-oxidizing gas exiting the waste heat recovery system is injected into the chamber (104) as a cooling gas. This improves the efficiency of the dry quenching process in accordance with the present disclosure as compared to dry quenching process without heat recovery.
Thus, the dry quenching process of the present disclosure re-utilizes the thermal energy generated in the inert gas during the dry quenching process thereby conserving energy in the range of 15% to 30% as compared to the conventional wet quenching process for quenching of white cement clinker. This enables reduction of greenhouse gases. As against the wet quenching process, usage of water is eliminated in the dry quenching process in accordance with the present disclosure, thereby saving water in

the range of 400 to 450 liters per ton of clinker. Thus, water as well as energy is conserved by using the dry quenching process of the present disclosure.
The embodiments herein and the various features and advantages details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification

specific to the contrary. TECHNICAL ADVANTAGES:
The technical advancements offered by the dry quenching process for white cement clinker manufacturing, of the present disclosure include the realization of:
• eliminating usage of water in quenching of cement clinker;
• energy conservation; and
• cost effective process of quenching white clinker.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.
Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included in the scope of the disclosure.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless

the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to", "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

WE CLAIM:
1. A dry quenching process for white cement clinker manufacturing, said process
comprises the steps of:
feeding hot cement clinker to a chamber; and
quenching the hot cement clinker in the chamber to produce white cement
clinker by injecting a non-oxidizing gas into the chamber through
• a first inlet for injecting the non-oxidizing gas along the inflow direction of the hot cement clinker, and
• a second inlet for injecting the non-oxidizing gas in a direction opposite the inflow direction of the hot cement clinker; and
recovering sensible heat from the gases exiting the chamber.
2. The process as claimed in claim 1, wherein the step of recovering sensible heat is followed by the step of recirculating the gases under pressure through the chamber.
3. The process as claimed in claim 1, wherein the sensible heat recovered in the step of recovering sensible heat is utilized for operation of an intended process.
4. The process as claimed in claim 1, wherein the non-oxidizing gas is selected from the group of gases consisting of carbon-dioxide, nitrogen, argon, neon, helium, krypton, xenon and radon.
5. The process as claimed in claim 1, wherein each of the inlets is defined by at least one entrance.
6. The process as claimed in claim 1, wherein the flow of the non-oxidizing gas within the chamber is actuated by controlling the flow of the non-oxidizing gas
, through the first inlet and the second inlet.