Use of enSodium DiacetateSDA -products from coal fired power plants as source of sulphur in agriculture

Flue gas desulphurisation is done by lime reactions in wet or semi-wet procedures. The spray drying process (SDA) is a semi-wet procedure. Lime solution will be sprayed into the exhaust of a burning plant before or after removing the fly ash. The product of this process is a dry and fine powdered material containing sulphur mainly bound as CaSO3. Due to its content of fly ash the products may contain impurities of environmental important elements. While gypsum is predominantly used in the building industry or as a filling compound, products from the spray drying absorption process are only partly utilised. The use of desulphurisation products as sulphur fertilisers in agriculture could cover the sulphur supply of the plants and would simultanesously contribute to appropriate recycling of these residues. In a field trial series on 4 sites in Northern and Central Germany the effect of five SDA-products with different fly ash contents on the sulphur nutritional status of oilseed rape, rye, wheat and barley was evaluated. The results show that all tested products are suitable for improving the sulphur nutritional status of the plants. The sulphite-sulphur is available immediately and doesn't affect plant-growth negatively. To prevent accumulation of undesired elements in soil it is necessary to determine the influence of SDA products on the content of environmental important elements in soil. Direct use of these fine powdered materials in fields requires fertiliser spreaders with worm-augers and dust protective facilities. Granulation of the products or mixing the products with animal slurry are other possibilities of application.