FIELD OF INVENTION:

The present invention is related to bentonite sulphur used in agriculture.

OBJECT OF THE INVENTION:

The objectives of the invention is to improve the performance of sulphur bentonite used as fertilizer in agriculture in terms of

1) Reduction in time of disintegration and

2) Improvement in particle size of sulphur after disintegration such that the average particle size will be less than 100 micron.

The improved process comprises of combining the sulfur slurry with a caustic metal base so as to produce a highly water dispersible sulfur fertilizer.

BACKGROUND OF THE INVENTION:

Sulphur bentonite is a fertilizer used for supplying elemental sulphur to the crops. Sulphur bentonite is produced by adding bentonite to molten sulphur in a pit. The slurry of molten sulphur and bentonite is then deposited on a steel belt in the form of droplets. The droplets are cooled and discharged as pastilles or semi-hemispherical granules. The importance of sulphur as a soil additive, either in the form of sulphur compounds or in its elemental form, with or without a medium such as clay has been widely understood. It is important that the elemental sulphur, as a soil additive, be in a finely divided form.

Bentonite primarily consists of montmorillonite clay. Montmorillonite has a three sheet layer structure with one alumina octahedral sheet sandwiched between two tetrahedral silica sheets. Some of the Al3+ ions in the octahedral sheet are substituted by Mg2+ that leads to the production of a negative charge which is balanced by an interlayer cation either Ca2+ or Na+ Montmorillonite has the ability to absorb water into the interlayer region thereby causing the clay to swell. When the bentonite is applied to the soil and comes into contact with soil moisture, it absorbs water and swells. The swelling causes the disintegration of the pastille leading to generation of fine sized sulphur particles. The sulphur particles in turn get oxidized to sulphate form by the action of bacteria, Thiobacillus. The sulphate ions are taken up by the plants. The rate of oxidation of elemental sulphur is determined by the particle size. Smaller the particle size of sulphur, faster is the rate of oxidation and hence more the availability of sulphur to crops. It is generally known that the desirable range for particle size of sulphur in soil is 50 to 100 microns. Sodium montmorillonite has higher water absorbing capacity than calcium montmorillonite. The commercial bentonite used for the production of sulphur bentonite contains a large percentage of calcium montmorillonite. Since montmorillonite has high exchange capacity, the calcium montmorillonite can be converted into sodium montmorillonite by exposing it to sodium ions. This work was aimed at developing a process for in-situ conversion of calcium montmorillonite to sodium montmorillonite during the production of sulphur bentonite in order to enhance the water absorption capacity of bentonite and thereby reduce the disintegration time and the sulphur particle size.

DETAILED DESCRIPTION:

A fertilizer composition with enhanced synergistic fertilizer activity is produced by combining the sulphur along with necessary caustic lye.

A caustic metallic base is a white solid available in pellets. It is predominantly ionic, containing sodium cations and hydroxide anions.

The work was carried out in the Granulation Laboratory of the Fertilizer Technology Centre at Vizag.

The source of sodium ions for converting calcium montmorillonite into sodium montmorillonite was 98% caustic metal base pellets. The caustic pellets were dissolved in water to produce aqueous ive. The lye was added to a mixture of bentonite and molten sulphur and mixed well The f,„a, mixture was then disturbed as droplets over a plate. The droplets upon cooling wormed past,„es.Tests were carried out to measure the disintegration tlmeandsulphurparticl size with the produced pastilles. The percentages of sulphur bentonite and caustic metal base were varied to determine the most suitable composition of the modified sulphur bentonite.

Example(l):

Test results conducted in Granulation Laboratory in Fertilizer Technology Centre, Vizag

Example(2): TRIAL CONDUCTED IN SULPHUR BENTONITE PLANT

During this trial the range 90-92% was arrived at and thereby the sulphur percentage was formulated for 90.5% and the caustic metal base percentage was varied in the range of 0.1% to 1%. Measured quantities of caustic lye and bentonite powder were added to molten sulphur and the slurry was kept in agitation for one hour. Later slurry was pumped to rotoformer. Product was continuously drawn for 1.5 hrs. Later caustic metal base percentage of the whole slurry was increased by adding additional lye to sulphur pit. At this percentage also product was drawn for 1.5 hrs. In the similar fashion caustic metal bas percentage was further increased.

The product characteristics of the above samples were as follows

The Important observations that were obvious at the end are:

1) Slurry as well as pastille's color turned to green on addition of caustic metal base lye.

2) Dispersion time is about 15-20 minutes. Best results obtained in the range of 0.1% to 1% addition.

3) In the above three trials, the rejects with respect to size were low at 50-100 kg/hr against that of 300 kg/hr without caustic metal base dosing.

It has been proved beyond doubt that there is very good improvement in dispersion quality of Bentonite sulphur by addition of caustic metal base in the range of 0.1% to 1% dosage. The purity of caustic metal base is preferred to be between 48-50%. The most preferred percentage of caustic metal base is in the range of 0.1% to 1% for sufficient performance. All the above examples, trials and reportings are presented to illustrate the invention but not to limit the scope.

From the above examples and trials, it is concluded that bentonite sulphur with caustic metal base exhibits enhanced dispersion property, the most desired property in agriculture use.

Although the present patent has been disclosed in terms of preferred embodiments it will be understood that numerous additional modifications and variations, could be made thereto without departing from the scope of invention.

WE CLAIM:

1. A fertilizer composition comprising of:

a. sulphur as fertilizer active ingredient, and

b. a disintegrating agent, wherein the disintegrating agent is a combination of swelling type clay and a caustic metal base.

2. The fertilizer composition as claimed in claim 1, wherein the swelling type clay is bentonite.

3. The fertilizer composition as claimed in claim 1, wherein the caustic metal base is a soluble compound providing cations and anions in a moist environment.

4. The fertilizer composition as claimed in claim 1, wherein the caustic metal base is sodium hydroxide.

5. The fertilizer composition as claimed in claim 1, wherein the caustic metal base is with 48-50% purity.

6. The fertilizer composition as claimed in claim 1, wherein the sulphur percentage is around 90-92%.

7. The fertilizer composition as claimed in claim 1, wherein the caustic metal base is in the range of 0.1-1%.

8. The fertilizer composition as claimed in claim 1, wherein the minimum caustic metal base percentage will be in the range of 0.1-1%.

9. The fertilizer composition as claimed in claim 1, wherein the most preferred percentage of caustic metal base is in the range of 0.1-1%.

10. The caustic metal base is added to the molten sulphur pit along with bentonite in the existing process for production of sulphur bentonite.