Investigation of coal slurry properties deposited in impoundments located in the upper silesian coal basin

Results of investigation of physical, chemical and energetic properties of steam and coking coal slurries deposited in twenty Polish impoundments are presented in the paper. Coal slurry was sampled in accordance with a certain procedure from different locations and depths at each impoundment whereas laboratory investigation was performed on averaged samples. The performed investigation include determination of chemical composition, moisture content, volatile matter, sulfur and calorific value at various states. Additionally, properties of coal slurry of particle size below 0.1 mm are presented. The average content of this fraction is approximately 62% and ranges at individual impoundments from 28 to 79%. An average calorific value in analytical state of coal slurries deposited in impoundments in the fraction below 0.1 mm is rather high (12.01 MJ/kg on average) in comparison to the average calorific value of impoundments in analytical state i.e. 16.4 MJ/kg. Average ash and sulfur contents of the coal slurries in analytical state is on average: 42.5% and 1.0% respectively. Transient moisture content of coal slurries in the analytical state is on average 22%, whereas the average volatile matter content is 20.0% Chemical composition is typical for coal tailings with low A1₂O ₃ and T1O₂ content. The results indicate considerable variations in the quality of coal slurries deposited in different impoundments due to different geology of coal deposits of the mines. For individual impoundment these differences are smaller which is demonstrated by a lower variation in the standard deviation.