Title of Invention	IMPROVED ACID TREATMENT PROCESS FOR CLAY
Abstract	A process for activation of smectite clay comprising the following steps: drying the smectite clay; cleaning the dried smectite clay and testing for hardness; segregating clay smectite clay less than 2 Mohs in batches for further treatment; checking the methylene blue value of each batch of the segregated clay and selecting batches with methylene blue value greater than 400 mg/g for further treatment; adjusting the clay moisture to 30-40% by addition of 12-15% sulfuric acid; extruding the moistened clay to a granular size of 12 to 15 mm; treating the granulated clay in a reactor with continuously circulating sulfuric acid at a temperature of 80-95 degree C till the total acidity is greater than 22 mg KOH/g and draining of 150/-5000 lit/min with water in accelerated cycles to remove ions clay soluble in water, while ensuring the total acidity of the clay remains greater than 22 mg KOH/g; drying of the washed clay to obtain acid treated clay dried clay to a particle size of predominantly of 2 mm to 0.25 mm an acid activated smectite clay.

Title of Invention

IMPROVED ACID TREATMENT PROCESS FOR CLAY

Abstract

A process for activation of smectite clay comprising the following steps: drying the smectite clay; cleaning the dried smectite clay and testing for hardness; segregating clay smectite clay less than 2 Mohs in batches for further treatment; checking the methylene blue value of each batch of the segregated clay and selecting batches with methylene blue value greater than 400 mg/g for further treatment; adjusting the clay moisture to 30-40% by addition of 12-15% sulfuric acid; extruding the moistened clay to a granular size of 12 to 15 mm; treating the granulated clay in a reactor with continuously circulating sulfuric acid at a temperature of 80-95 degree C till the total acidity is greater than 22 mg KOH/g and draining of 150/-5000 lit/min with water in accelerated cycles to remove ions clay soluble in water, while ensuring the total acidity of the clay remains greater than 22 mg KOH/g; drying of the washed clay to obtain acid treated clay dried clay to a particle size of predominantly of 2 mm to 0.25 mm an acid activated smectite clay.

Full Text	FORM – 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 PROVISIONAL (See section 10 and rule 13) IMPROVED ACID TREATMENT PROCESS FOR CLAY SHAH GHETAN NAVNITHLAL an Indian National of Wyoming Co-op Hsg. Society, IV Floor, Flat No.4, 12 A, Little Gibbs Road, Malabar Hill, Mumbai 400 006, Maharashtra, India, THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION. Field of the invention The present invention relates to activated clay. Particularly, the present invention relates to a process for washing of clay during activation. Prior art Naturally occurring clays are known to exhibit excellent adsorbing and decolorizing properties. These properties can further be enhanced by treating clay with suitable mineral acid leading to clay activation. The acid activation of clay is often accompanied by a change in key physical properties of clay such as surface acidity, surface area, pore volume etc. US Patent No 6,602,816 is directed towards acid treatment of clay. j According to this process, the clay sample in granular form is contacted with an aqueous acid solution of mineral acid. The acid- treatment process is conducted at a temperature of about 60-100°C for about 3-20 hours. The acid concentration is about 20-35% by mass. After the treatment, the mother liquor containing aluminum, magnesium, calcium and iron salts is recovered and the acid treated clay is washed with water, dried, classified to obtain the activated regular shaped clay particles as a finished product. US Patent No. 5,908,500 discloses a method for preparing bleaching clay. The method comprises combining intercalating clay with mineral acid and organic polar liquid admixture. The slurry so formed is agitated for 1-3 minutes. Thereafter, the slurry is filtered through a Buckner filter to remove the polar organic liquid and air-dried at ambient temperature to yield bleaching clay that exhibits enhanced bleaching activity. 2 Japanese Patent application No. JP 335/1948 discloses a method of producing activated clay. The process comprises kneading clay in water and molding into a desired particle size (typically 0.5-30 mm), introducing resulting clay into an acid resistant container, and heating and circulating an inorganic acid therein to activate the clay. In the processes described m these patents and conventionally used in the industry, clay is washed after acid treatment with water to remove excess acid and leached out salts of Mg++, Ca++ and the like, adhered to the clay surface as a result of, acid treatment. Removal of leached out heavy metal particles such as lead, mercury and the like is also important as the activated clay may also be used in treating edible oil and other sensitive material where contamination with heavy metal particles may be undesirable. However, these objectives are only partially achieved by the conventional washing process. Further, conventional process leads to the loss of material in shifting the acid treated clay to the washing cycle. Particularly, the conventional washing cycle is time consuming and not eco-friendly. Objects of the invention It is an object of the present invention to provide an improved washing process for the production of acid treated clay. It is another object of the present invention to provide a process to remove excess acid of the treated clay. It is another object of the present invention to provide a process for effective removal of leached out salts of Mg++, Ca"^ adhered on the clay surface and heavy metal particles. 3 It is another object of the present invention to provide a process for acid treatment and washing of clay without need to remove the clay from the treatment container. It is another object of the present invention to provide a washing process for activated clay, which is economic and environment-friendly. Description of the invention Accordingly, the present invention provides a process for the production of activated clay by treating Smectite clay or composition thereof with mineral acid. The activation of clay is carried out in the following manner: Typically, Smectite clay such as Ca-Montmorillonite is used for acid treatment. However, many other clay types and mixtures thereof having different physical characteristics may also be advantageously used if desired. The initial moisture content of the clay is about 30-50 %. First step is the mining of clay, which is in the form of lumps. These lumps are dried in sunlight or by using any-other type of drying or heating method. After drying, the lumps of clay are crushed to convert the lumps into smaller particles of 50-60 mm in diameter. After drying, the clay is cleaned manually to remove: 1. Sand and stones 2. Particles with metallic iron material which are generally dark reddish brown and hence can be removed easily by color sorting and 4 3. Harder particles which are more than 2 Mohs hardness and generally contain hematite. Testing of clay: Hardness testing of clay is done by standard methods such as abrasive index method. This clay is analyzed for Methylene Blue value, by titrating the clay solution (in tetra sodium pyrophosphate) with Methylene blue dye solution. The Methylene blue value of the bentonite clay is about 400, which indicates that the clay has good resistance for deactivation. The clay is also subjected to chemical analysis. Acid treatment of Clay: The assorted clay is transferred to a pan mixer, wherein, typically 10-12 % dilute H2SO4 is added to the clay at room temperature. The sulfuric acid used for the acid treatment is of about 98.5 % purity. The clay-acid mixture is rotated at a pre-determined rpm for pre-determined time. The mother liquor containing dissolved Al, Ca, Mg ori Fe salts is recovered. The moisture content of clay at this stage is 25-27 %. Clay-acid mixture after removing the mother liquor is homogenized, dried in air and granulated to 12-15 mm (diameter) size particles using a granulator. Clay is screened once or twice at this stage to remove any oversize particles. The sulfuric acid activated clay is conveyed to a reactor using a conveyer belt for second acid treatment. The reactor used for second acid treatment is an acid resistant rubber lined fiberglass reactor. The reactor is preheated to 80-85°C before adding the clay into the reactor. 5 In a separate compartment or mixing tank, dilute mineral acid (35-40 %) solution is prepared from mineral acid solution. This solution is then slowly passed through the reactor containing Smectite clay. The sulfuric acid; solution is circulated typically in a bottom to up mode using a pump, for 8-15 hrs. The acidity of the treated clay is periodically measured by withdrawing samples at fixed time intervals and is called the free acidity of clay. The total acidity minus free acidity is the net effective or working acidity of the clay. It is expressed in delta. The working acidity should be around 13-14 delta. pH of solution is around 4-5. Washing of activated clay After the desired activation" is achieved, the: pump is switched off and the dilute acid containing salts of Mg and Ca is "drained from the reactor. However, some heavy metal particles; and salts of Ca and Mg still remain adhered on the clay surface, so the acid activated clay is washed with soft water (containing less than 18 ppm of]Ca++ and Mg++).at room temperature. The washing of activated clay, according to the present invention, is done by accelerated water washing cycles for effective washing. The water is circulated through the reactor from top to bottom direction. The speed of water circulation through the reactor is about 200-350 lit/min. 15 tons of the activated clay is washed using 35,000-40,000 liters of soft water. After 4-5 water washing cycles, the pump is switched off, and the wash-water containing leached salts adhered or adsorbed on the clay surface is drained off. The acidity of this washed clay is estimated by titrating with KOH solution. The acidity of water washed clay is about xx and pH of solution is about 4-5 and moisture content of the clay is about 60-70 %. 6 The wet clay is taken out arid dried to a moisture level of 5% in a gasifier at a desired temperature. The dried clay is ground in a roller mill (Raymond roller) and sifted to desired particle size using vibrosifier, prior to use. The activated bentonite clay prepared according to process of the present invention was used in the treatment of aromatic hydrocarbon stream and was found to be satisfactory. While considerable emphasis has been placed herein on the specific process parameters/ components of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without: departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as alimitation. (6ked this 13th to November 2006 Mohan Dewan Of R.K.Dewan & Co. Applicant's Patent Attorney 7

Full Text

FORM – 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL

(See section 10 and rule 13)
IMPROVED ACID TREATMENT PROCESS FOR CLAY
SHAH GHETAN NAVNITHLAL
an Indian National
of Wyoming Co-op Hsg. Society, IV Floor, Flat No.4,
12 A, Little Gibbs Road, Malabar Hill, Mumbai 400 006,
Maharashtra, India,

THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION.

Field of the invention
The present invention relates to activated clay. Particularly, the present invention relates to a process for washing of clay during activation.
Prior art
Naturally occurring clays are known to exhibit excellent adsorbing and decolorizing properties. These properties can further be enhanced by treating clay with suitable mineral acid leading to clay activation. The acid activation of clay is often accompanied by a change in key physical properties of clay such as surface acidity, surface area, pore volume etc.
US Patent No 6,602,816 is directed towards acid treatment of clay.
j According to this process, the clay sample in granular form is contacted with
an aqueous acid solution of mineral acid. The acid- treatment process is
conducted at a temperature of about 60-100°C for about 3-20 hours. The acid
concentration is about 20-35% by mass. After the treatment, the mother
liquor containing aluminum, magnesium, calcium and iron salts is recovered
and the acid treated clay is washed with water, dried, classified to obtain the
activated regular shaped clay particles as a finished product.
US Patent No. 5,908,500 discloses a method for preparing bleaching clay. The method comprises combining intercalating clay with mineral acid and organic polar liquid admixture. The slurry so formed is agitated for 1-3 minutes. Thereafter, the slurry is filtered through a Buckner filter to remove the polar organic liquid and air-dried at ambient temperature to yield bleaching clay that exhibits enhanced bleaching activity.
2

Japanese Patent application No. JP 335/1948 discloses a method of producing activated clay. The process comprises kneading clay in water and molding into a desired particle size (typically 0.5-30 mm), introducing resulting clay into an acid resistant container, and heating and circulating an inorganic acid therein to activate the clay.
In the processes described m these patents and conventionally used in the industry, clay is washed after acid treatment with water to remove excess acid and leached out salts of Mg++, Ca++ and the like, adhered to the clay surface as a result of, acid treatment. Removal of leached out heavy metal particles such as lead, mercury and the like is also important as the activated clay may also be used in treating edible oil and other sensitive material where contamination with heavy metal particles may be undesirable.
However, these objectives are only partially achieved by the conventional washing process. Further, conventional process leads to the loss of material in shifting the acid treated clay to the washing cycle. Particularly, the conventional washing cycle is time consuming and not eco-friendly.
Objects of the invention
It is an object of the present invention to provide an improved washing
process for the production of acid treated clay.
It is another object of the present invention to provide a process to remove
excess acid of the treated clay.
It is another object of the present invention to provide a process for effective
removal of leached out salts of Mg++, Ca"^ adhered on the clay surface and
heavy metal particles.
3

It is another object of the present invention to provide a process for acid treatment and washing of clay without need to remove the clay from the treatment container.
It is another object of the present invention to provide a washing process for activated clay, which is economic and environment-friendly.
Description of the invention
Accordingly, the present invention provides a process for the production of activated clay by treating Smectite clay or composition thereof with mineral acid.
The activation of clay is carried out in the following manner:
Typically, Smectite clay such as Ca-Montmorillonite is used for acid
treatment. However, many other clay types and mixtures thereof having
different physical characteristics may also be advantageously used if desired.
The initial moisture content of the clay is about 30-50 %. First step is the
mining of clay, which is in the form of lumps. These lumps are dried in
sunlight or by using any-other type of drying or heating method. After
drying, the lumps of clay are crushed to convert the lumps into smaller
particles of 50-60 mm in diameter.
After drying, the clay is cleaned manually to remove:
1. Sand and stones
2. Particles with metallic iron material which are generally dark reddish brown and hence can be removed easily by color sorting and
4

3. Harder particles which are more than 2 Mohs hardness and generally contain hematite.
Testing of clay:
Hardness testing of clay is done by standard methods such as abrasive index
method.
This clay is analyzed for Methylene Blue value, by titrating the clay solution
(in tetra sodium pyrophosphate) with Methylene blue dye solution. The
Methylene blue value of the bentonite clay is about 400, which indicates that
the clay has good resistance for deactivation.
The clay is also subjected to chemical analysis.
Acid treatment of Clay:
The assorted clay is transferred to a pan mixer, wherein, typically 10-12 % dilute H2SO4 is added to the clay at room temperature. The sulfuric acid used for the acid treatment is of about 98.5 % purity. The clay-acid mixture is rotated at a pre-determined rpm for pre-determined time. The mother liquor containing dissolved Al, Ca, Mg ori Fe salts is recovered. The moisture content of clay at this stage is 25-27 %.
Clay-acid mixture after removing the mother liquor is homogenized, dried in air and granulated to 12-15 mm (diameter) size particles using a granulator. Clay is screened once or twice at this stage to remove any oversize particles. The sulfuric acid activated clay is conveyed to a reactor using a conveyer belt for second acid treatment. The reactor used for second acid treatment is an acid resistant rubber lined fiberglass reactor. The reactor is preheated to 80-85°C before adding the clay into the reactor.
5

In a separate compartment or mixing tank, dilute mineral acid (35-40 %) solution is prepared from mineral acid solution. This solution is then slowly passed through the reactor containing Smectite clay. The sulfuric acid; solution is circulated typically in a bottom to up mode using a pump, for 8-15 hrs. The acidity of the treated clay is periodically measured by withdrawing samples at fixed time intervals and is called the free acidity of clay. The total acidity minus free acidity is the net effective or working acidity of the clay. It is expressed in delta. The working acidity should be around 13-14 delta. pH of solution is around 4-5.
Washing of activated clay
After the desired activation" is achieved, the: pump is switched off and the dilute acid containing salts of Mg and Ca is "drained from the reactor. However, some heavy metal particles; and salts of Ca and Mg still remain adhered on the clay surface, so the acid activated clay is washed with soft water (containing less than 18 ppm of]Ca++ and Mg++).at room temperature. The washing of activated clay, according to the present invention, is done by accelerated water washing cycles for effective washing. The water is circulated through the reactor from top to bottom direction. The speed of water circulation through the reactor is about 200-350 lit/min. 15 tons of the activated clay is washed using 35,000-40,000 liters of soft water. After 4-5 water washing cycles, the pump is switched off, and the wash-water containing leached salts adhered or adsorbed on the clay surface is drained off.
The acidity of this washed clay is estimated by titrating with KOH solution. The acidity of water washed clay is about xx and pH of solution is about 4-5 and moisture content of the clay is about 60-70 %.
6

The wet clay is taken out arid dried to a moisture level of 5% in a gasifier at
a desired temperature.
The dried clay is ground in a roller mill (Raymond roller) and sifted to
desired particle size using vibrosifier, prior to use.
The activated bentonite clay prepared according to process of the present
invention was used in the treatment of aromatic hydrocarbon stream and was
found to be satisfactory.
While considerable emphasis has been placed herein on the specific process parameters/ components of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without: departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as alimitation.
(6ked this 13th to November 2006
Mohan Dewan
Of R.K.Dewan & Co.
Applicant's Patent Attorney
7

Documents:

1876-mum-2006-abstract (complete).doc

1876-mum-2006-abstract (complete).pdf

1876-mum-2006-abstract(7-11-2007).doc

1876-mum-2006-abstract(7-11-2007).pdf

1876-mum-2006-claims (complete).doc

1876-mum-2006-claims (complete).pdf

1876-mum-2006-claims(granted)-(13-11-2006).doc

1876-mum-2006-claims(granted)-(13-11-2006).pdf

1876-mum-2006-correspondence(24-12-2007).pdf

1876-mum-2006-correspondence(ipo)-(3-2-2009).pdf

1876-mum-2006-correspondence-received-13112006.pdf

1876-mum-2006-correspondence-received.pdf

1876-mum-2006-description (complete).pdf

1876-mum-2006-description (provisional).pdf

1876-mum-2006-drawing(7-11-2007).pdf

1876-mum-2006-drawings.pdf

1876-mum-2006-form 1(13-11-2006).pdf

1876-mum-2006-form 18(24-12-2007).pdf

1876-mum-2006-form 2(granted)-(13-11-2006).doc

1876-mum-2006-form 2(granted)-(13-11-2006).pdf

1876-mum-2006-form 26(13-11-2006).pdf

1876-mum-2006-form 3(13-11-2006).pdf

1876-mum-2006-form 5(6-11-2007).pdf

1876-mum-2006-form 9(13-3-2008).pdf

1876-mum-2006-form-1.pdf

1876-mum-2006-form-2 (complete).doc

1876-mum-2006-form-2 (complete).pdf

1876-mum-2006-form-2 (provisional).doc

1876-mum-2006-form-2 (provisional).pdf

1876-mum-2006-form-26.pdf

1876-mum-2006-form-3.pdf

1876-mum-2006-form-5.pdf

1876-mum-2006-form-9.pdf

1876-mum-2006-form-pct-isa-210(13-11-2006).pdf

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Patent Number

229063

Indian Patent Application Number

1876/MUM/2006

PG Journal Number

10/2009

Publication Date

06-Mar-2009

Grant Date

13-Feb-2009

Date of Filing

13-Nov-2006

Name of Patentee

SHAH CHETAN NAVNITHLAL

Applicant Address

WYOMING CO-OP. HSG. SOCIETY, IV FLOOR, FLAT NO. 4, 12A, LITTLE GIBBS ROAD, MALABAR HILL, MUMBAI-400006,

Inventors:

#	Inventor's Name	Inventor's Address
1	SHAH CHETAN NAVNITHLAL	Wyoming Co-op. Hsg. Society, IV Floor, Flat No. 4, 12A, Little Gibbs road, Malbar Hill, Mumbai-400006,

PCT International Classification Number

C11B13/04,C11B13/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA