Title of Invention	A SYNERGISTIC COMPOSITION USEFUL FOR MAKING SLOW RELEASE HIGH CONTENT SULPHUR GLASS
Abstract	The process of the present invention provides a high content sulphur glass capable of slow release of sulphur which particularly relates to the application of the glass as fertilizer for agricultural applications and for any other plant which requires sulphur as one of the constituents of their elemental combinations. The material may have applications in such other fields where controlled release of sulphur is required such as fungicide, pesticide, weedicide and for purposes other than agriculture.

Title of Invention

A SYNERGISTIC COMPOSITION USEFUL FOR MAKING SLOW RELEASE HIGH CONTENT SULPHUR GLASS

Abstract

The process of the present invention provides a high content sulphur glass capable of slow release of sulphur which particularly relates to the application of the glass as fertilizer for agricultural applications and for any other plant which requires sulphur as one of the constituents of their elemental combinations. The material may have applications in such other fields where controlled release of sulphur is required such as fungicide, pesticide, weedicide and for purposes other than agriculture.

Full Text	The present invention relates to a synergistic composition useful for making slow release high content sulphur glass The process of the present invention provides a high content sulphur glass capable of slow release of sulphur which particularly relates to the application of the £lass as fertiliser for agricultural applications and for any other plant which requires sulphur as one of the constituents of their elemental combinations. The material may have applications in such other fields where controlled release of sulphur is required such as fungicide, pesticide, weedicide and for purposes other than agriculture. The present day method of making sulphate glasses essentially consists of fusing KHSO4 or the mixtures of K2SO4 and ZnSO4, K2SO4 , ZnSO4 and NaPO3; ZnSO4 , KPO,, and NaPO3; K2SO4, Na2SO4, K2SO4 and NaPO3; Na2SO4, ZnSO4 and NaPO3 The reference for which may be made to, T. Portland and W. A. Weyl, "Formation of Sulfate Glass" J. Am. Ceram. Soc. 33 186-187 (1950); P. S. L. Narasimham and K. J. Rao, "Phase Diagram and Glass Formation in the K2SO4-ZnSO4 System", J. Non-Cryst. Solids, 27, 225-246 (1978); V. L. Mamoshin, V. G. Arkhipov, P. I. Bular, L. V. Ivanova and O. J. Pupkova, "Glass Formation in the System R2SO4(RHSO4)-ZnSp4-NaPO3(P2O5), R=Li, Na, K, Fiz. Khim. Stekla 16, 860-866 (1990); V. L. Mamoshin, " Formation of Low Melting Glasses in ZnSO4-KPO3-NaPO3 and Li2SO4-Na2SO4-K2SO4-NaPO3 System", Glass and Ceramics 53, 166-168 (1996). The main drawbacks of the above processes are: 1. Release of sulphur in the leached solution is high. 2. The glass contains alkali like Na-O, Li2O which are harmful to the plants and increases alkalinity of the soil which hinders absorption of other nutrients by the plants. 3. The glass contains high percentage of ZnO which is toxic to the plants The main object of the present invention is to formulate a synergistic composition useful for making slow release high content sulphur glass which does not contain alkali like Na2O, Li2O and ZnO. Another object is to provide a process of making slow release high content sulphate glass which obviates the drawbacks as detailed above. Yet another object of the present invention is to increase the sulphur content of the prepared glass. Still another object of the present invention is to reduce the sulphur releasing rate when leached. Another object of the present invention is to reduce calcium oxide content in the glass to reduce calcium load on the soil. Still another object of the present invention is to provide a sulphur releasing glass which minimizes pollution to underground water by reducing leaching rate of the constituent elements. Yet another object of the present invention is to provide a slow release sulphur source to the plant all through the farming period to enhance nitrogen assimilation. Still another object of the present invention is to reduce loss of sulphate radicals to the environment so that toxic sulphur compounds do not form through microbial transformation and do not cause environmental pollution. Yet another object of the present invention is to maintain acidity of the soil. Still another object of the present invention is to provide essential nutrients like potassium and phosphorous with low release rate in the leached solution. Accordingly, the present invention provides A synergistic composition useful for making slow release high content sulphur glass consisting of P2O5 in the range of 7 to 40 wt% SO3 " 16to57wt% K20 " 15to30wt% CaO " 5 to 20 wt% AI2O3 " 0 to 2 wt% In an embodiment of the present invention the source of P2O5 is obtained from orthophosphoric acid, ammonium dihydrogen orthophosphate, diammonium hydrogen orthophosphate, potassium dihydrogen phosphate, tri-calcium phosphate, aluminium phosphate or the mixtures thereof. In another embodiment of the present invention the S03 is obtained from potassium sulphate, potassium disulphate, potassium persulphate, potassium bisulphate, calcium sulphate, ammonium sulphate, aluminium sulphate or the mixtures thereof. In yet another embodiment of the present invention the source of K2O in the composition may be provided as chemical compounds such as potassium sulphate, potassium disulphate, potassium persulphate, potassium bisulphate, potassium carbonate or the mixtures thereof. In still another embodiment of the present invention the CaO is obtained from tri-calcium phosphate, calcium sulphate, calcium carbonate, gypsum or the mixtures thereof. In yet another embodiment of the present invention the Al2O3 is obtained from aluminum surphate, aluminum orthophosphate, alumina or the mixtures thereof. In a embodiment of the present invention the melting may be effected for a time period in the range of 20 to 120 minutes . The composition of the present invention is not a mere admixture but a synergistic mixture having properties which are distinct from the mere aggregation of the properties of the individual constituents.and is not a product of chemical reaction. . Accordingly the present invention provides a process of making glass from the synergistic composition as detailed above which comprises proportioning and thorough mixing of the above composition, melting the composition at a temperature in the range of 750-1050 °C for a time 20 to 120 minutes or till the melt becomes free from the mixed components to « obtain homogenized glass melt, followed by quenching the melt by "known methods. The details of the process of the present invention are given below: 1. Chemical compounds providing P2O5 7 to 40 wt. %, SO3 16 to 57 wt. %, K2O 15 to 30 wt. %, CaO 5 to 20 wt. %, A12O3 0 to 2 wt. % are mixed thoroughly. 2. The mixed materials are melted at 750-1050 °C for 20 to 120 minutes or till the melt becomes free from the mixed components to obtain homogenized glass melt. 3. The homogenous melt was quenched by pouring to obtain slow release high content sulphur glass. Sulphur is one of the major nutrient required for healthy plant growth and crop yield and because of strong metabolic coupling between S and N assimilation deficiency of sulphur limits nitrogen utilization efficiency of the plant and thus affecting- plant growth, development and yield. Sulphur performs many important functions in the plant including synthesis of proteins, oils and vitamins. Gypsum , single- super phosphate and iron pyrites are the conventional sources of sulphur fertiliser of which gypsum is widely used to provide necessary sulphur to the plant but due to its high solubility large part of sulphate radicals derived from it percolates in the underground water damaging its quality, also repeated application of gypsum to the soil enhances calcium load on the soil. A much more successful technique resides in preparing sulphur containing glass which is added directly to the soil. Under wet or damp growing conditions small amount of sulphate radicals are made available in the intermediate vicinity of the seeds and plant roots. For this the solubility of the glass in water should be relatively small in order to prevent a quick release of nutrient elements and also to prevent them from being rendered unsuitable to the plants through chemical reaction in the soil. Yet the solubility should not be so small that the rate of release of nutrients from the glass is inadequate for plant growth. Further, the glass must not contain any such element which is harmful to the plant and its growth. Further by proper selection of the glass composition soil condition can be altered locally, in particular in an alkaline soil, which is generally regarded as being difficult from which to supply essential nutrients, to less alkaline or even acidic micro-environment around the roots of plants or around seeds. (S ''O42-) 2- is the main glass building unit in the sulphate glasses In phosphate -sulphate glass SO4 2- enters the glass matrix of phosphate glass forming P-O-S bonds. Ca2+and K+ ion bridges the glass network. Higher field strength of Ca;i ions reduces the number of non-bridging oxygen and thus reduces its solubility. Thus the novelty of the process of the present invention lies in the fact that sulphur will be released slowly into the soil in presence of water as and when required at the same time maintaining the acidity of the soil as the alkali metals are not available to the reacting system in the present material. Additionally the glass do not contain harmful elements to the plants like Na2O, Li2O and ZnO. The inventive step lies in the incorporation of P2O5, SO3, K2O2, CaO and Al2O3 in a novel glass composition having high weight percent of SO, The following examples are provided by the way of illustration of the present invention and should not be construed to limit the scope of the present invention Example 1 The glass was made by thoroughly mixing 11.8 g of ammonium dihydrogen oilhophosphale, 78.7 g of potassium disulphate, 17.8 g of gypsum and 6.0 g of aluminium sulphate and heating the mixture at 1050ºC for 30 minutes and then by quenching the melt. The glass so obtained was ciiecked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass, by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved glass was weighed after drying the residue to the constant weight Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed afler filtration and drying to the constant weight. Solubility of glass is 41.6% and percentage of sulphur extraction is 52.5%. Example 2 The glass was prepared by thoroughly mixing 47.2 g potassium sulphate, 22.4 g of tri-calcium phosphate and 49.3 g ammonium dihydrogen orthophosphate and heating the mixture at 800 "C for 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass , by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved glass was weighed afler drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 27.2% and percentage of sulphur extraction is 30.6%. Example 3 The glass was made by thoroughly mixing 17.8 g potassium sulphate, 31.7 g gypsum, 61.8g ammonium dihydrogen orthophosphate and 28.2 g potassium carbonate and heating the mixture at 900 "C for 20 minutes followed by heating to 1050 "C for another 15 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass , by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 his. The solution isthen filtered. The imdissolvcd glass was weighed after drying the residue to the constant weight Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 46.8% and percentage of sulphur extraction is 86.0%. Example 4 Another way of preparing the glass was to make a mixture of 32.4 g of ammonium dihydrogcn orthophosphate, 35.3 g of tri-calcium phosphate and 44.6 g of potassium sulphate and heating the mixture at 850 °C for 20 minutes followed by further heating to 950 "C for another 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from tolal sulphur content in glass, by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 his The solution is then filtered, 'flic undissolvcd glass was weighed after drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 21.6% and percentage of sulphur extraction is 26.5%. l',\:implc 5 Another way of making the glass was by fusing a homogeneous mixture of 52.9g of potassium sulphate, , 15.0 g of tri-calcium phosphate, 52.2 g of ammonium di-hydrogen orthophosphate and 0.2 g of aluminium sulphate at 750 "C for 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass, by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved portion was weighed after drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 38.3% and percentage of sulphur extraction is 78.8%. Example 6 Another way of making the glass was by melting a homogeneous mixture of 20.0g of calcium carbonate, 50.6g of potassium sulphate, 60.Og of ammonium dihydrogen orthophosphate and 1.3 g of alumina at 1000 "C for 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass , by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved glass was weighed after drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium « sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 9.3% and percentage of sulphur extraction is 11.0%. From the above examples it was observed that the glass obtained have solubility in the range of 9.0 to 47.0 % and the percentage of sulphur extraction is between 11.0 to 86.0 %. The main advantages of the present invention are : 1. Slow release high content sulphur glass useful as a novel fertiliser source. 2. Increased sulphur content in the glass results it being useful as a fungicide, pesticide. 3. Reduced sulphur releasing rate in the leached solution allows its application in single basal dose. 4. Glass is free from harmful sodium and lithium oxides which oids sodicity of the soil. 5. Glass is free from harmful zinc oxide which is toxic for plant growth. 6. When applied to the soil it reduces calcium load on the soil. 7. Reduces atmospheric and under-ground water pollution. 8. Enhances nitrogen assimilation by the plant. 9. Maintains acidity of the soil. 10. It also provides essential nutrients like potassium, phosphorous and calcium. We claim : 1. A synergistic composition useful for making slow release high content sulphur glass consisting of P2O5 in the range of 7 to 40 wt% S03 " 16to57wt% K20 " 15to30wt% CaO " 5 to 20 wt% AI203 " Oto2wt% 2. A synergistic composition as claimed in claim 1 wherein P2O5 is obtained from orthophosphoric acid .ammonium dihydrogen orthophosphate, diammonium hydrogen orthophosphate, potassium dihydrogen orthophosphate, tri-calcium phosphate, aluminium orthophosphate or the mixtures thereof. 3. A synergistic composition as claimed in calim 1-2 wherein SO3 is obtained from potassium sulphate, potassium disulphate, potassium persulphate, otassium bisulphate, calcium sulphate, ammonium sulphate, aluminium sulphate or the mixtures thereof. 4. A synergistic composition as claimed in claim 1-3 wherein K20 is obtained from potassium sulphate, potassium disulphate, potassium per sulphate, potassium bi sulphate, potassium carbonate or the mixtures thereof. 5. A synergistic composition as claimed in claim 1-4 wherein the CaO is obtained from tri-calcium phosphate, calcium sulphate, calcium carbonate, gypsum or the mixtures thereof. 6. A synergistic composition as claimed in claims 1-5 wherein AI2O3 is obtained from aluminium sulphate, aluminium orthophosphate, alumina or the mixtures thereof. 7. A process of making glass from the synergistic composition as claimed in claim 1-6 which comprises proportioning and thorough mixing of the above composition, melting the mixed composition at a temperature in the range of 750-1050°C for a time of 20 to 120 minutes till the melt becomes free from the mixed components to obtain homogenized glass melt, followed by quenching the melt by known methods. 8. A synergistic composition useful for making slow release high content sulphur glass substantially as herein described with reference to the examples.

Full Text

The present invention relates to a synergistic composition useful for making slow release high content sulphur glass The process of the present invention provides a high content sulphur glass capable of slow release of sulphur which particularly relates to the application of the £lass as fertiliser for agricultural applications and for any other plant which requires sulphur as one of the constituents of their elemental combinations. The material may have applications in such other fields where controlled release of sulphur is required such as fungicide, pesticide, weedicide and for purposes other than agriculture.
The present day method of making sulphate glasses essentially consists of fusing KHSO4 or the mixtures of K2SO4 and ZnSO4, K2SO4 , ZnSO4 and NaPO3; ZnSO4 , KPO,, and NaPO3; K2SO4, Na2SO4, K2SO4 and NaPO3; Na2SO4, ZnSO4 and NaPO3 The reference for which may be made to, T. Portland and W. A. Weyl, "Formation of Sulfate Glass" J. Am. Ceram. Soc. 33 186-187 (1950); P. S. L. Narasimham and K. J. Rao, "Phase Diagram and Glass Formation in the K2SO4-ZnSO4 System", J. Non-Cryst. Solids, 27, 225-246 (1978); V. L. Mamoshin, V. G. Arkhipov, P. I. Bular, L. V. Ivanova and O. J. Pupkova, "Glass Formation in the System R2SO4(RHSO4)-ZnSp4-NaPO3(P2O5), R=Li, Na, K, Fiz. Khim. Stekla 16, 860-866 (1990); V. L. Mamoshin, " Formation of Low Melting Glasses in ZnSO4-KPO3-NaPO3 and Li2SO4-Na2SO4-K2SO4-NaPO3 System", Glass and Ceramics 53, 166-168 (1996). The main drawbacks of the above processes are:
1. Release of sulphur in the leached solution is high.
2. The glass contains alkali like Na-O, Li2O which are harmful to the plants and increases
alkalinity of the soil which hinders absorption of other nutrients by the plants.

3. The glass contains high percentage of ZnO which is toxic to the plants
The main object of the present invention is to formulate a synergistic composition useful
for making slow release high content sulphur glass which does not contain alkali like
Na2O, Li2O and ZnO.
Another object is to provide a process of making slow release high content sulphate glass
which obviates the drawbacks as detailed above.
Yet another object of the present invention is to increase the sulphur content of the
prepared glass.
Still another object of the present invention is to reduce the sulphur releasing rate when
leached.
Another object of the present invention is to reduce calcium oxide content in the glass to
reduce calcium load on the soil.
Still another object of the present invention is to provide a sulphur releasing glass which
minimizes pollution to underground water by reducing leaching rate of the constituent
elements.
Yet another object of the present invention is to provide a slow release sulphur source to
the plant all through the farming period to enhance nitrogen assimilation.
Still another object of the present invention is to reduce loss of sulphate radicals to the
environment so that toxic sulphur compounds do not form through microbial
transformation and do not cause environmental pollution.
Yet another object of the present invention is to maintain acidity of the soil.

Still another object of the present invention is to provide essential nutrients like potassium and phosphorous with low release rate in the leached solution.
Accordingly, the present invention provides A synergistic composition useful
for making slow release high content sulphur glass consisting of
P2O5 in the range of 7 to 40 wt%
SO3 " 16to57wt%
K20 " 15to30wt%
CaO " 5 to 20 wt%
AI2O3 " 0 to 2 wt%
In an embodiment of the present invention the source of P2O5 is obtained from orthophosphoric acid, ammonium dihydrogen orthophosphate, diammonium hydrogen orthophosphate, potassium dihydrogen phosphate, tri-calcium phosphate, aluminium phosphate or the mixtures thereof. In another embodiment of the present invention the S03 is obtained from potassium sulphate, potassium disulphate, potassium persulphate, potassium bisulphate, calcium sulphate, ammonium sulphate, aluminium sulphate or the mixtures thereof.
In yet another embodiment of the present invention the source of K2O in the composition may be provided as chemical compounds such as potassium sulphate, potassium disulphate, potassium persulphate, potassium bisulphate, potassium carbonate or the mixtures thereof.

In still another embodiment of the present invention the CaO
is obtained from tri-calcium phosphate, calcium sulphate,
calcium carbonate, gypsum or the mixtures thereof.
In yet another embodiment of the present invention the Al2O3
is obtained from aluminum surphate, aluminum
orthophosphate, alumina or the mixtures thereof.
In a embodiment of the present invention the melting may be effected for a time period in the range of 20 to 120 minutes .
The composition of the present invention is not a mere admixture but a synergistic mixture having properties which are distinct from the mere aggregation of the properties of the individual constituents.and is not a product of chemical reaction. . Accordingly the present invention provides a process of making glass from the synergistic composition as detailed above which comprises proportioning and thorough mixing of the above composition, melting the composition at a temperature in the range of 750-1050 °C for a time 20 to 120 minutes or till the melt becomes free from the mixed components to
«
obtain homogenized glass melt, followed by quenching the melt by "known methods. The details of the process of the present invention are given below:
1. Chemical compounds providing P2O5 7 to 40 wt. %, SO3 16 to 57 wt. %, K2O 15 to 30
wt. %, CaO 5 to 20 wt. %, A12O3 0 to 2 wt. % are mixed thoroughly.
2. The mixed materials are melted at 750-1050 °C for 20 to 120 minutes or till the melt
becomes free from the mixed components to obtain homogenized glass melt.

3. The homogenous melt was quenched by pouring to obtain slow release high content sulphur glass.
Sulphur is one of the major nutrient required for healthy plant growth and crop yield and because of strong metabolic coupling between S and N assimilation deficiency of sulphur limits nitrogen utilization efficiency of the plant and thus affecting- plant growth, development and yield. Sulphur performs many important functions in the plant including synthesis of proteins, oils and vitamins. Gypsum , single- super phosphate and iron pyrites are the conventional sources of sulphur fertiliser of which gypsum is widely used to provide necessary sulphur to the plant but due to its high solubility large part of sulphate radicals derived from it percolates in the underground water damaging its quality, also repeated application of gypsum to the soil enhances calcium load on the soil. A much more successful technique resides in preparing sulphur containing glass which is added directly to the soil. Under wet or damp growing conditions small amount of sulphate radicals are made available in the intermediate vicinity of the seeds and plant roots. For this the solubility of the glass in water should be relatively small in order to prevent a quick release of nutrient elements and also to prevent them from being rendered unsuitable to the plants through chemical reaction in the soil. Yet the solubility should not be so small that the rate of release of nutrients from the glass is inadequate for plant growth. Further, the glass must not contain any such element which is harmful to the plant and its growth. Further by proper selection of the glass composition soil condition can be altered locally, in particular in an alkaline soil, which is generally regarded as being

difficult from which to supply essential nutrients, to less alkaline or even acidic micro-environment around the roots of plants or around seeds.
(S ''O42-) 2- is the main glass building unit in the sulphate glasses In phosphate -sulphate glass SO4 2- enters the glass matrix of phosphate glass forming P-O-S bonds. Ca2+and K+ ion bridges the glass network. Higher field strength of Ca;i ions reduces the number of non-bridging oxygen and thus reduces its solubility.
Thus the novelty of the process of the present invention lies in the fact that sulphur will be released slowly into the soil in presence of water as and when required at the same time maintaining the acidity of the soil as the alkali metals are not available to the reacting system in the present material. Additionally the glass do not contain harmful elements to the plants like Na2O, Li2O and ZnO. The inventive step lies in the incorporation of P2O5, SO3, K2O2, CaO and Al2O3 in a novel glass composition having high weight percent of SO,
The following examples are provided by the way of illustration of the present invention and should not be construed to limit the scope of the present invention
Example 1
The glass was made by thoroughly mixing 11.8 g of ammonium dihydrogen oilhophosphale, 78.7 g of potassium disulphate, 17.8 g of gypsum and 6.0 g of aluminium sulphate and heating the mixture at 1050ºC for 30 minutes and then by quenching the melt. The glass so obtained was ciiecked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass, by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The

undissolved glass was weighed after drying the residue to the constant weight Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed afler filtration and drying to the constant weight. Solubility of glass is 41.6% and percentage of sulphur extraction is 52.5%.
Example 2
The glass was prepared by thoroughly mixing 47.2 g potassium sulphate, 22.4 g of tri-calcium phosphate and 49.3 g ammonium dihydrogen orthophosphate and heating the mixture at 800 "C for 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass , by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved glass was weighed afler drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 27.2% and percentage of sulphur extraction is 30.6%.
Example 3
The glass was made by thoroughly mixing 17.8 g potassium sulphate, 31.7 g gypsum, 61.8g ammonium dihydrogen orthophosphate and 28.2 g potassium carbonate and heating the mixture at 900 "C for 20 minutes followed by heating to 1050 "C for another 15 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass , by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24

his. The solution isthen filtered. The imdissolvcd glass was weighed after drying the residue to the constant weight Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 46.8% and percentage of sulphur extraction is 86.0%.
Example 4
Another way of preparing the glass was to make a mixture of 32.4 g of ammonium dihydrogcn orthophosphate, 35.3 g of tri-calcium phosphate and 44.6 g of potassium sulphate and heating the mixture at 850 °C for 20 minutes followed by further heating to 950 "C for another 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from tolal sulphur content in glass, by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 his The solution is then filtered, 'flic undissolvcd glass was weighed after drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 21.6% and percentage of sulphur extraction is 26.5%.
l',\:implc 5
Another way of making the glass was by fusing a homogeneous mixture of 52.9g of potassium sulphate, , 15.0 g of tri-calcium phosphate, 52.2 g of ammonium di-hydrogen orthophosphate and 0.2 g of aluminium sulphate at 750 "C for 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for

percent of sulphur extracted from total sulphur content in glass, by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved portion was weighed after drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 38.3% and percentage of sulphur extraction is 78.8%.
Example 6
Another way of making the glass was by melting a homogeneous mixture of 20.0g of calcium carbonate, 50.6g of potassium sulphate, 60.Og of ammonium dihydrogen orthophosphate and 1.3 g of alumina at 1000 "C for 30 minutes and then by quenching the melt. The glass so obtained was checked for its solubility rate and for percent of sulphur extracted from total sulphur content in glass , by treating 1.0 gm of glass powder of size 0.6 to 1.0 mm with 50 ml of distilled water for 24 hrs. The solution is then filtered. The undissolved glass was weighed after drying the residue to the constant weight. Percent of sulphur extracted from total weight was obtained by precipitating filtrate as barium
«
sulphate, which was weighed after filtration and drying to the constant weight. Solubility of glass is 9.3% and percentage of sulphur extraction is 11.0%.
From the above examples it was observed that the glass obtained have solubility in the range of 9.0 to 47.0 % and the percentage of sulphur extraction is between 11.0 to 86.0 %. The main advantages of the present invention are :
1. Slow release high content sulphur glass useful as a novel fertiliser source.
2. Increased sulphur content in the glass results it being useful as a fungicide, pesticide.

3. Reduced sulphur releasing rate in the leached solution allows its application in single
basal dose.
4. Glass is free from harmful sodium and lithium oxides which oids sodicity of the soil.
5. Glass is free from harmful zinc oxide which is toxic for plant growth.
6. When applied to the soil it reduces calcium load on the soil.
7. Reduces atmospheric and under-ground water pollution.
8. Enhances nitrogen assimilation by the plant.
9. Maintains acidity of the soil.
10. It also provides essential nutrients like potassium, phosphorous and calcium.

We claim :
1. A synergistic composition useful for making slow release high content
sulphur glass consisting of
P2O5 in the range of 7 to 40 wt%
S03 " 16to57wt%
K20 " 15to30wt%
CaO " 5 to 20 wt%
AI203 " Oto2wt%
2. A synergistic composition as claimed in claim 1 wherein P2O5 is obtained
from orthophosphoric acid .ammonium dihydrogen orthophosphate,
diammonium hydrogen orthophosphate, potassium dihydrogen
orthophosphate, tri-calcium phosphate, aluminium orthophosphate or the
mixtures thereof.
3. A synergistic composition as claimed in calim 1-2 wherein SO3 is
obtained from potassium sulphate, potassium disulphate, potassium
persulphate, otassium bisulphate, calcium sulphate, ammonium
sulphate, aluminium sulphate or the mixtures thereof.
4. A synergistic composition as claimed in claim 1-3 wherein K20 is
obtained from potassium sulphate, potassium disulphate, potassium per
sulphate, potassium bi sulphate, potassium carbonate or the mixtures
thereof.

5. A synergistic composition as claimed in claim 1-4 wherein the CaO is
obtained from tri-calcium phosphate, calcium sulphate, calcium
carbonate, gypsum or the mixtures thereof.
6. A synergistic composition as claimed in claims 1-5 wherein AI2O3 is
obtained from aluminium sulphate, aluminium orthophosphate, alumina
or the mixtures thereof.
7. A process of making glass from the synergistic composition as claimed
in claim 1-6 which comprises proportioning and thorough mixing of the
above composition, melting the mixed composition at a temperature in
the range of 750-1050°C for a time of 20 to 120 minutes till the melt
becomes free from the mixed components to obtain homogenized glass
melt, followed by quenching the melt by known methods.
8. A synergistic composition useful for making slow release high content
sulphur glass substantially as herein described with reference to the
examples.

Documents:

662-del-2000-abstract.pdf

662-del-2000-claims.pdf

662-del-2000-correspondence-others.pdf

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Patent Number

232543

Indian Patent Application Number

662/DEL/2000

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

18-Mar-2009

Date of Filing

18-Jul-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH,

Applicant Address

RAFI MARG, NEW DELHI-110001

Inventors:

#	Inventor's Name	Inventor's Address
1	GOURKRISHNA DASMOHAPATRA,	CENTRAL GLASS & CERAMIC RESEARCH INSTITUTE , CALCUTA 700 032 INDIA.
2	KOUSHIK GHOSH,	CENTRAL GASS & CERAMIC RESEARCH INSTITUTE, CALAUTTA 700 032,INDIA
3	SAMIR KUMARBASU	CENTRAL GASS & CERAMIC RESEARCH INSTITUTE, CALAUTTA 700 032,INDIA
4	AHINDRA KUMAR CHAUDHURI,	CENTRAL GASS & CERAMIC RESEARCH INSTITUTE, CALAUTTA 700 032,INDIA
5	NISHA BISWAS,	CENTRAL GASS & CERAMIC RESEARCH INSTITUTE, CALAUTTA 700 032,INDIA

PCT International Classification Number

C03C 3/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA