Investigation of possibilities of use of waste oils for cleaning coal by hydrophobic flocculation

This thesis study consists of two stages. In the first part, hydrophobic flocculation experiments were carried out to enrich the fine-size (-212 µm) lignite coal supplied from the Mine field operating in the Beyşehir region. In the experiments, 3 different binding fluids, vegetable waste oil, hydraulic waste oil and engine waste oil, were used. Parameters such as pH of the suspension, solid rate effect, sodium silicate (Na2SiO3) amount, mixing speed, oil amount, flocculation time and floc growth time were examined in detail. The success of the hydrophobic flocculation process was evaluated by the ash content and combustion recovery (CR%) of the flocs obtained after the experiment. In experiments using vegetable waste oil, 41.58% ash removal was achieved and flocs with 16.38% ash content were obtained with 99.77% CR. While ash removal for hydraulic waste oil and engine waste oil was 41.45 and 43.22 (%), respectively, 16.33% and 17.03% ash-containing flocs were obtained with 99.90% and 99.06% CR respectively. In the second part, it was investigated to obtain clean coal by adding the acquired flocs to the system twice under the effects of the parameters determined in the hydrophobic flocculation experiments. Ash contents and CR values of clean coals obtained in the first and second stages of vegetable waste oil, hydraulic waste oil and engine waste oils and hydrophobic flocculation experiments, respectively; 15.95%, 97.98%, 13.48%, 99.48% for vegetable waste oil, 15.37%, 96.53%, 14.21%, 99.67% for hydraulic waste oil and 15.81%, 98.66%, 14.19%, 99.98% for engine waste oil.