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The granulation of composite mixtures with potential use in agriculture as soil-conditioners gives good possibility for their mechanical distribution in the soil through different fertilizer-spreader machines. The granulated products ensure slower speed of the nutrients extraction in the soil solution and in the same time long-term presence in the soils and better utilization by the plants. This work presents the results from investigations on the granulation of composite mixtures for production of soil-conditioners. All used mixtures are based on ashes from burning wooden wastes and green lye -- wastes from pulp production. For some mixtures sulphuric acid was also used in order to compensate of alkaline reactions of other components and to obtain better properties of the soil-conditioner. The granulation process was realized by the method of press granulation, and the obtained granules were tested with a hydraulic press to determine the compressive strength of the products. The obtained values were compared with similar products. The moisture content of the granulated soil-conditioners were determined and compared also with similar type soil-conditioners. [ABSTRACT FROM AUTHOR]

Minimization and utilization of industrial wastes as secondary raw material resources is essential to achieve sustainable technologies. This work presents the results of a study of the properties of ash resulting from combustion and industrial processes in the complex 'Svilosa" in Svishtov. Using appropriate analysis and physico-chemical techniques, chemical and phase composition of the generated ashes, the main crystal phases which are formed in the realization of industrial technologies are identified. The generated wood ashes are alkaline in nature and contain essential nutrients needed for development of different plant species. The survey makes a recommendation to use industrial wastes generated by the industrial complex to obtain composite solid mixtures, suitable for use as soil improvers in agriculture. [ABSTRACT FROM AUTHOR]

Attention has been focused on the treatment of lignite-fired flue gas in order to use lignite in an environmentally friendly way -- (i) low-CO2 emission, (ii) production of a valuable by-product, (iii) no discharge of wastewater, (iv) direct removal of SO3 (strong toxicity), and (v) treatment of high SO2 concentration. Based on these criteria, electron beam irradiation with ammonia injection was tested on a semi-pilot scale: 800Nm³h-1 flow rate, 5500ppm SO2, 70ppm NOx, 22% flue gas moisture, and 75-80 °C at the reactor outlet. As an energy-saving measure, a low dose (5kGy) of irradiation was applied: the problem lay in the by-product quality. It is considered that (NH4)2SO3 and NH4HSO3 produced by thermal reactions are oxidized to form (NH4)2SO4 (fertilizer) by an electron beam. However, not all reactions were complete because the by-product contained small amounts of H2SO4 and NH2SO3NH4 (herbicide), so a vegetable pot test was performed to study the by-product quality; no adverse effect was observed. It is inferred from the pot test that slightly acidic soil may protect vegetables from disease and a small amount of NH2SO3NH4 probably affects woody species and not herbaceous species. It is concluded that the electron beam system is noted as a multi-component pollution control process (removal of NOx, SO3, SO2 and dioxins) and this system will contribute to environmentally friendly use of lignite as well as agricultural productivity via fertilizer supply. [ABSTRACT FROM AUTHOR]