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Abstract

The cement production process is associated with the emission of dust. These are mainly CKD (cement kiln dust) and BPD (by-pass dust), classified as wastes from group 10 – Wastes from thermal processes, subgroups 10 and 13 – wastes from manufacture of cement, lime and plaster and articles and products made from them. Cement kiln dust is a waste of variable composition and properties, which makes it a difficult material to recover. The main directions of recovery presented in the world literature indicate the use of dust from cement kilns in cement, mortar and concrete production, the production of bricks and in order to improve soil quality and wastewater treatment. Factors affecting chemical and phase compositions of dust from cement kilns are the reason why each waste should be analyzed individually. The paper presents the results of the analysis of the cement kiln dust after dedusting cement kilns and two bypass dusts. Analysis of the chemical composition has shown significant concentrations of chlorine, potassium and calcium in all wastes. The content of: Si, S, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Zr, Pb, and Bi has also been confirmed. The analyzed dusts were characterized by the presence of carbonates (calcite, dolomite, and arcanite), quartz, alite, belite, sylvine, anhydrite, and portlandite in their phase composition. The leachates which were characterized by an alkaline reaction. In terms of leachability, high concentrations of chlorine ions in the analyzed dust leachates were confirmed, which significantly limits their use.
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Abstract

The use of biomass in the energy industry is the consequence of ongoing efforts to replace Energy from fossil fuels with energy from renewable sources. However, due to the diversity of the biomass, its use as a solid fuel generates waste with diverse and unstable chemical composition. Waste from biomass combustion is a raw material with a very diverse composition, even in the case of using only one type of biomass. The content of individual elements in fly ash from the combustion of biomass ranges from zero to tens of percent. This makes it difficult to determine the optimal recovery methods. The ashes from the combustion of biomass are most commonly used in the production of building materials and agriculture. This article presents the elemental composition of the most commonly used biomass fuels. The results of the analysis of elemental composition of fly ashes from the combustion of forest and agricultural biomass in fluidized bed boilers used in the commercial power industry were presented. These ashes are characterized by a high content of calcium (12.3–19.4%), silicon (1.2–8.3%), potassium (0.05–1.46%), chlorine (1.1–6.1%), and iron (0.8–6.5%). The discussed ashes contained no sodium. Aluminum was found only in one of the five ashes. Manganese, chromium, copper, nickel, lead, zinc, sulfur, bismuth, titanium and zirconium were found in all of the examined ashes. The analysis of elemental composition may allow for a preliminary assessment of the recovery potential of a given ash.
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