FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention
A METHOD OF BENEFICIATING CRUSHED REFINED SODA FINES
2. Applicant(s)

Name

Nationality

Address

TATA CHEMICALS LTD.

INDIA

BOMBAY HOUSE, 24 HOM1 MODI STREET,
MUMBAI-400001

3. Preamble to the description
COMPLETE SPECIFICA TION
The following specification particularly describes the invention and the manner in which it is
to be performed.

The invention relates to a method of beneficiating crushed refined soda fines. More particularly the invention relates to a method of beneficiating of crushed refined soda fines to make it suitable for use in an detergent formulation. DESCRIPTION OF RELATED ART
Conventional dry mix detergent product formulation are based on synthetic soda ash which is very pure in quality and free from organic matter, clay insolubles and fluorides. Dry detergent compositions are formed by mixing soda ash with one or more surfactants. In addition to soda ash and surfactants other additives such as builders, brighteners, soil release agents, perfumes etc are also added to detergents. Normally, detergent product is free flowing, has a good bright blue color and exhibits good performance in cleaning and detergency.
In detergents, soda ash is used as a builder to emulsify oil stains, to reduce the deposit of dirt during washing and rinsing, to deliver a smoother surface in the formulation, to provide alkalinity for cleaning, and to soften laundry water. In powdered laundry detergent, soda ash conditions the water and enhances the processing and performance of formulated cleaning products. Two grades of soda ash i.e., light soda ash and dense soda ash are used for the production of detergents. However, since soda ash has to be manufactured, the cost of manufacturing soda ash adds to the cost of the detergent.
In view of this there is a need to develop a process by which cheaper and naturally available raw material may be used in place of soda ash for the production of detergents.
SUMMARY
The invention relates to a method of beneficiating crushed refined soda fines
comprising obtaining crushed refined soda fines with a particle size lower than or equal to
3mm by sieving the crushed refined soda fines, drying the crushed refined soda fines to
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reduce the moisture content, and reducing the particle size of the crushed refined soda fines to below 500 microns.
The invention also relates to a method of beneficiating crushed refined soda fines comprising obtaining crushed refined soda fines with a particle size lower than or equal to 3mm by sieving the crushed refined soda fines, reducing the particle size of the crushed refined soda fines to below 500 microns, and drying the crashed refined soda fines to reduce the moisture content.
The invention also relates to a detergent comprising beneficiated crushed refined soda fines. BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The accompanying drawings illustrate the preferred embodiments of file invention and together with the following detailed description serve to explain the principles of the invention.
Fig 1 tabulates the comparative composition of soda ash and crushed refined soda fines.
Fig 2 is a schematic illustration of a method of beneficiating crushed refined soda fines in accordance with an embodiment.
Fig 3 is a schematic illustration of a method of beneficiating crushed refined soda fines in accordance with an alternative embodiment.
Fig 4 tabulates the composition of raw and sieved crushed refined soda fines.
Fig 5 tabulates the result of 3 detergent formulations made by using samples of
crushed refined soda fines having particle size of 2mm or less.
DESCRIPTION OF PREFERRED EMBODIMENTS
To promote an understanding of the principles of the invention, reference will be made
to the embodiment illustrated in the drawings and specific language will be used to describe
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the same. It will nevertheless be understood that no limitation of scope of the invention is thereby intended, such alterations and further modifications in the illustrated method and such further applications of the principles of the inventions as illustrated therein being contemplated as would normally occur to one skilled in art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
Crushed refined soda fines is typically a waste that is generated from soda ash plants that use trona soda for the production of soda ash. In the production of soda ash, trona soda is washed to remove insoluble impurities. The effluent that comes out from the overflow of washery of a soda ash plant is referred to as crushed refined soda fines slurry. This crushed refined soda fines slurry is discharged back into the source from where crushed refined soda is obtained. The liquid is drained out to leave crushed refined soda fines that is dried in sunlight. The crushed refined soda fines so obtained contain sodium carbonate along with sodium bicarbonate and large quantities of impurities. Figure 1 tabulates the comparative composition of soda ash and crushed refined soda fines.
Crushed refined soda fines which obtained as waste from the soda ash plant is contaminated with clay insolubles, organic matters, sodium fluoride and has particle size that is very coarse and not suitable for detergent production.
A method of beneficiating crushed refined soda fines is described. More particularly a method of beneficiating crushed refined soda fines to make it suitable for use in a detergent composition is described.
The method involves the treatment of crushed refined soda fines by sieving the raw
crushed refined soda fines to reduce the solid impurities present in the crushed refined soda
fines. The crushed refined soda fines with reduced amount of impurities so obtained is then
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dried to reduce the moisture content of the crushed refined soda fines. The crushed refined soda fines obtained after drying is ground to obtain beneficiated crushed refined soda fines that is suitable for use in detergent formulation.
Alternatively, the method involves the treatment of crushed refined soda fines by sieving the raw crushed refined soda fines to reduce the solid impurities present in the crushed refined soda fines. The sieved crushed refined soda fines is then ground to reduce the size of the crushed refined soda fines particles. The ground crushed refined soda fines is dried to reduce the moisture content of the crushed refined soda fines to obtain beneficiated crushed refined soda fines that is suitable for use in detergents formulation.
With reference to figure 2, a method of beneficiating crushed refined soda fines in accordance with an aspect is illustrated. At step 101 crushed refined soda fines is sieved to obtain crushed refined soda fines having a particle size preferably less than or equal to 3 mm. Sieving removes crushed refined soda fines having a size larger than 3 mm from the raw crushed refined soda fines along with larger insoluble impurities. Crushed refined soda fines having a particle size preferably less than or equal to 3mm is used for further processing. The sieved crushed refined soda fines is then dried at step 102 at predetermined temperature for a predetermined period of time to reduce the moisture present in the crushed refined soda fines. The dried crushed refined soda fines obtained from step 102 is then ground at step .103 as illustrated in figure 2. The crushed refined soda fines obtained after grinding at step 103 is sieved at step 104 to obtain beneficiated crushed refined soda fines (105) suitable for use in a detergent formulation.
With reference to figure 3, an alternative method of beneficiating.crushed refined
soda fines is illustrated. At step 101 crushed refined soda fines is sieved to obtain crushed
refined soda fines having a particle size preferably less than or equal to 3mm. Sieving
removes crushed refined soda fines having a size larger that 3mm from the crushed refined
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soda fines along with larger insoluble impurities. Crushed refined soda fines having a particle
size less than or equal of 3mm is preferably used for further processing. The sieved crushed
refined soda fines is then ground at step 103. Grinding is done to obtain crushed refined soda
fines having particle size preferably in the range of 200 to 300 microns or lower. The ground
crushed refined soda fines is dried at step 102 at predetermined temperature for a
predetermined period of time to reduce the moisture present in the crushed refined soda fines
to obtain beneficiated crushed refined soda fines (105) suitable for use in a detergent
formulation.
In accordance with an aspect the raw crushed refined soda fines is sieved through a
sieve having 2mm mesh size to obtain crushed refined soda fines having particle size less
than or equal to 2mm. Sieving the crushed refined soda fines removes larger insoluble
impurities that are present in the raw crushed refined soda fines. More than 60% of the
impurities are removed through 10% of coarse particles of crushed refined soda fines having
size more than 2mm. By way of a specific example the amount of Sodium Fluoride,
insolubles, organic matter and Iron present in raw crushed refined soda fines in a sample
experiment are reduced from 2.01%, 0.89%, 0.30 % and 400 ppm to 0.88%,0.24%,0.11% and
110 ppm respectively in the sieved crushed refined soda fines having particle size less than
2mm. Figure 4 tabulates the composition of raw and sieved crushed refined soda fines.
By way of a specific example crushed refined soda fines screened through 2mm sieve,
was used in the formulation for making detergent product. It was found that the detergent
product made using a sample screened through 2mm mesh had three major shortcomings. It
was lumpy on storing, had no free flow and had higher particle size of greater than 500
micron in the range of 65 to 70 %. Figure 5 tabulates the result of 3 detergent formulations
using a sample of crushed refined soda fines having particle size of 2mm or less. The higher
particle size and high crystalline moisture content of crushed refined soda fines was found to
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be responsible for lumpy, high particle size and very low free flow in detergent product. As a result further processing is required of the sieved crushed refined soda fines to make it suitable for use in detergent formulation.
Moisture present in the crushed refined soda fines adversely affects the use of crushed refined soda fines in a detergent formulation. The crushed refined soda fines is dried to reduce the moisture content. However, while the moisture in, crushed refined soda fines is reduced on heating, sodium bicarbonate component of the crushed refined soda fines also starts to deplete. Crushed refined soda fines contains sodium carbonate and sodium bicarbonate that provides reserve basicity that controls the pH of the detergent formulation. Accordingly, drying is carried out by heating the crushed refined soda fines at a predetermined temperature for a predetermined period of time.
In accordance with an aspect the crushed refined soda fines is dried without substantially depleting the sodium bicarbonate content. The presence of sodium bicarbonate in the crushed refined soda fines benefits the use of enzymes at higher pH values.
In accordance with an aspect the crushed refined soda fines is dried by heating at a temperature between. 130° C to 160° C and preferably the crushed refined soda fines is dried by heating at a temperature of 150° C.
In accordance with an aspect the crushed refined soda fines is dried by heating for a period of 1 hour to 2.5 hours and preferably the crushed refined soda fines is dried by heating for a period of 2 hours.
In accordance with an aspect the crushed refined soda fines is dried to obtain crushed refined soda fines having a minimum of 7% sodium bicarbonate and maximum moisture content of 5%. In accordance with a preferred embodiment the crushed refined soda fines is dried to obtain crushed refined soda having 10% sodium bicarbonate content and 4.9%
moisture content.
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In accordance with an aspect the crushed refined soda fines may be ground by any means including but not limited to a hammer mill. In accordance with an aspect the crushed refined soda fines is ground to reduce the size of particles of crushed refined soda fines to 200 microns to 300 microns and preferably the crushed refined soda fines is ground to reduce the size of particles of crushed refined soda fines to 250 microns.
In accordance with an aspect the ground crushed refined soda fines is further sieved to remove crushed refined soda fines having a particles size more than 200 to 300 microns. In accordance with a preferred embodiment the crushed refined soda fines are sieved through a sieve of mesh size 250 micron.
In accordance with an aspect the crushed refined soda fines obtained by this process may be used in the manufacture of detergents. INDUSTRIAL APPLICABILITY
The process as described allows the use of a waste product; crushed refined soda fines that is typically produced during soda ash manufacture, for the manufacture of detergents. The process for obtaining crushed refined soda fine suitable for use in detergent formulation is both simple and efficient. Moreover the crushed refined soda fines so obtained from the process may be used for production of detergents that are suitable for use in both soft and hard water.
When used in the detergent formulations suitable for use in hard water, the fluoride content in the crushed refined soda fines reacts with the calcium that is present in hard water to form insoluble Calcium Fluoride by the following formula: 2NaF + CaCl2 = 2NaCl + CaF2
This removes the calcium that is present in hard water. It is found that often more than
95% of fluorine present in the beneficiated crushed refined soda fines, reacts with calcium
ions present in hard water and reduces the hardness by more than 50%. Thus when used in a
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detergent formulation suited for hard water crushed refined soda fines reduces hardness of water, no loss of active detergent takes place and no or very small quantity of sequestering agent is required in the formulation.
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We Claim:
1. A method of beneficiating crushed refined soda fines comprising:
obtaining crushed refined soda fines with a particle size lower than or equal to
3mm by sieving the crushed refined soda fines;
drying the crushed refined soda fines to reduce the moisture content; and reducing the particle size of the crushed refined soda fines to below 500
microns.
2. A method of beneficiating crushed refined soda fines comprising:
obtaining crushed refined soda fines with a particle size lower than or equal to 3mm by sieving the crushed refined soda fines;
reducing the particle size of the crushed refined soda fines to below 500 microns; and
drying the crushed refined soda fines to reduce the moisture content.
3. A method as claimed in claim 1 or 2 wherein the crushed refined soda fines is sieved to obtain crushed refined soda fines having a particle size lower than or equal to 2mm.
4. A method as claimed in claim 1 or 2 wherein the drying is carried out at a temperature between 130°C to 160°C.
5. A method as claimed in claim 1 or 2 wherein the drying is carried out at a temperature of l50°C.
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6. A method as claimed in claim 1 or 2 wherein the drying is carried out for a period of 1 hour to 2.5 hours and preferably for a period of 2 hours.
7. A method as claimed in claim 1 or 2 wherein the crushed refined soda fines is dried without substantially depleting the sodium bicarbonate content.
8. A method as claimed in claim 7 wherein the crushed refined soda fines is dried to . obtain crushed refined soda fines having a minimum of 7% sodium bicarbonate and maximum moisture content of 5%.
9. A method as claimed in claim 7 wherein the crushed refined soda fines is dried to obtain crushed refined soda having 10% sodium bicarbonate content and 4.9% moisture content.
10. A method as claimed in claim 1 or 2 wherein the particle size of the crushed refined soda fines is reduced to 300 to 200 microns and preferably the particle size of the crushed refined soda fines is reduced to 250 microns.
11. A method as claimed in claim 1 or 2 wherein the particle size of the crushed refined soda fines is reduced by grinding the crushed refined soda fines in a hammer mill.
12. Beneficiated crushed refined soda fines as prepared by the method of claim I or 2.
13. A detergent comprising beneficiated crushed refined soda fines.
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14. A method of refining crushed refined soda fines substantially as herein described with reference to and as illustrated by the accompanying figures.
15. A detergent composition substantially as herein described with reference to and as illustrated by the accompanying figures.


Dated this 14th day of October 2008

Essenese Obhan Of Obhan & Associates Agent for the Applicant

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