Study of the Dispersion of Agricultural Sulfur Granules Preparedin Optimum Solidification Temperature

Document Type : Research Paper

Author

Research Institute of Petroleum Industry

Abstract

On the basis of environmental and safety reasons, hardness of agricultural sulfur granules should be high enough to have minimum dust formation during transportation and storage. On the other hand, by using agricultural sulfur, soil indigenous thiobacillus bacteria can oxidize elemental sulfur to sulfuric acid and decrease the soil pH. Sulfur particle size is one of the most important parameters, which affect the oxidation rate. Thus, hardness of sulfur granules should be low enough to be easily crushed to fine particles. In this research, first, hardness and electromicroscopic structure of elemental sulfur granules, solidified at different medium temperatures were investigated and the optimum temperature was determined. The results indicated that the optimum temperature is 30°C. At higher temperatures, the percent of dust formation was considerably increased. In the next stage, the agricultural sulfur and the enriched sulfur with Fe, Zn and Mn were prepared at optimum medium temperature. Mechanical strength, abrasion resistance and dispersion percent of the prepared granules were measured. The data indicated that sulfur fertilizer granules were harder than elemental sulfur ones probably due to their inorganic content. In addition, their dispersion in contact with water was significantly increased compared with elemental sulfur granules so that more than 94 percent of granules crushed to fine particles during 2 hours.

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منابع
[1] Tabatabai M.A., Sulfur in Agriculture, 1st Ed., American Society of Agronomy Inc., 1986.
[2] رهبر شمس‌کار ک.، بیابانی ط.، علایی ا.، آشوری م. و رضایی زاده ع.، بررسی جامع مصارف گوگرد در کشاورزی، پژوهشگاه صنعت نفت،‌ 1380.
[3] Boswell C.C. & Friesen D.K., Elemental sulfur fertilizers and their use on crops and pastures, Fert. Res., 35, pp.127-149, 1993
[4] Yang Z., Stöven K., Haneklaus S., Singh B.R. & Schnug E., Elemental Sulfur Oxidation by Thiobacillus spp. and Aerobic Heterotrophic Sulfur-Oxidizing Bacteria, Pedosphere, 20, pp. 71-79, 2010.
[5] Germida J.J. & Janzen H.H., “Factors affecting the oxidation of elemental sulfur in soils”, Fert. Res., 35, pp.101-114, 1993.
[6] The Canadian sulphur industry, Sulphur, 318, pp. 18-20, 2008.
[7] Sawyer E.W., Stable particulate suspensions, U.S. Patent 4, 062, 694, 1977
[8] Boswell C.C., Owers W.R., Swanney B. & Rothbaum H.P., “Sulfur/sodium bentonite mixtures as sulfur fertilizers: 1. The effects of S/Na-bentonite ratios on the rate of dispersion and particle size distribution of elemental sulfur dispersed from laboratory-produced prills”, Fert. Res.,15, pp. 13-31, 1988.
[9] Young D.C., Controlling sulfur particle hardness, U. S. Patent 4, 215, 996, 1980.
[10] Davis C.S. & Hyne J.B., “Thermo mechanical analysis of elemental sulphur: The effects of thermal history and ageing, Thermochim” , Acta, 15, pp. 375 -385, 1976.
[11] Blight K.R., Candy R.M. & Ralph D.E., “The preferential oxidation of orthorhombic sulfur during batch culture”, Hydrometallurgy, 99, pp. 100 -104, 2009.
[12] Rutland D.W., Manual for determining physical properties of fertilizer, 2nd Ed., IFDC Publication, 1993.
[13] Zafaran industrial group company Ltd., Googerd90 data sheet, http://zafaran.net/googerd.html, 2010.
[14] Scafè E., Nardella A., “Elastic properties of polycrystalline elemental sulphur”, J. Mater. Sci., 40, pp. 3813 -3816, 2005.