Sulphur-containing fertilizers and process for the preparation thereof
Process for the manufacture of sulphur-containing fertilizer compositions, comprising the steps of: a} providing a slurry of at least one phosphate-based fertilizer material selected from the group consisting of ammonium phosphates, ammonium phosphate based nitrogen-phosphorus-potassium (NPK) compounds, super phosphates and partially acidulated phosphate rocks; b) bringing said slurry into contact with at least one anionic surfactant and elemental sulphur; c) introducing the mixture obtained in step b} into a granulator unit in order to obtain granules of the fertilizer composition, wherein the at least one phosphate-based fertilizer material is present in an amount in the range of at least 50 wt. %, the elemental sulphur is present in an amount in the range of from 1 to 25 wt. % and the anionic surfactant is present in an amount in the range of from 0.001 to 3 wt. % based on the overall weight of the fertilizer composition. The present invention also provides a fertilizer composition.
1. A process for the manufacture of sulphur-containing fertilizer compositions, said process comprising the steps of:
a) providing a slurry of at least one phosphate-based fertilizer material selected from the group consisting of ammonium phosphates, ammonium phosphate based nitrogen-phosphorus-potassium (NPK) compounds, super phosphates and partially acidulated phosphate rocks;
b) bringing said slurry into contact with at least one anionic surfactant and a liquid phase of elemental sulphur; and
c) introducing the mixture obtained in step b) into a granulator unit in order to obtain granules of the fertilizer composition,
wherein the at least one phosphate-based fertilizer material is present in an amount in the range of at least 50 wt. %, the elemental sulfur is present in an amount in the range of from 1 to 25 wt. % and the at least one anionic surfactant is present in an amount in the range of from 0.001 to 3 wt. % based on the overall weight of the fertilizer composition.
2. A process as claimed in claim 1 , wherein elemental sulphur comprises molten sulphur.
3. A process as claimed in claim 1 , wherein the at least one anionic surfactant comprises a lignosulphonate.
4. A process as claimed in claim 1 , wherein the at least one anionic surfactant is present in an amount in the range of from 0.05 to 3 wt. % with respect to the weight of the overall fertilizer composition.
5. A process as claimed in claim 1 , wherein the at least one anionic surfactant is present in an amount in the range of from 0.1 to 2.0 wt. %, with respect to the weight of the overall fertilizer composition.
6. A fertilizer composition comprising:
a) elemental sulphur in an amount in the range of from 1 to 25 wt. %, based on the overall weight of the fertilizer composition;
b) at least one phosphate-based fertilizer material selected from the group consisting of ammonium phosphates, ammonium phosphate based nitrogen-phosphorus-potassium (NPK) compounds, super phosphates and partially acidulated phosphate rocks present in an amount of at least 50 wt. %, based on the overall weight of the fertilizer composition; and
c) at least one anionic surfactant present in an amount in the range of from 0.001 to 3 wt. % based on the overall weight of the fertilizer composition,
wherein the at least one anionic surfactant is dispersed throughout the fertilizer composition.
7. A fertilizer composition as claimed in claim 6 , wherein the at least one anionic surfactant comprises a lignosulphonate.
8. A fertilizer composition as claimed in claim 7 , wherein the at least one anionic surfactant comprises a lignosulphonate selected from the group consisting of alkali metal salts of lignosulphonic acid, alkaline earth metal salts of lignosulphonic acid and ammonium salts of lignosulphonic acid.
9. A fertilizer composition as claimed in claim 6 , wherein the at least one anionic surfactant is present in an amount in the range of from 0.05 to 3 wt. % with respect to the weight of the overall fertilizer composition.
10. A fertilizer composition as claimed in claim 6 , wherein the at least one anionic surfactant is present in an amount in the range of from 0.1 to 2.0 wt. %, with respect to the weight of the overall fertilizer composition.