Siberian Federal University

The comparative study of thermal decomposition of organic type sapropel (Kachkulnya lake) and organo-mineral type sapropel (Barchin lake) from Novosibirsk region was carried out by DTG-DCK and XRD methods. It was established that the chemical composition of sapropel has the significant influence on their behavior. In argon stream the thermal conversion of organic mass (OM) of organic type sapropel is a one-step process in the temperature range 261- 447 C, with a maximum speed of weight loss 2 wt. % / min. at 346 C. At the same conditions two stages of OM decomposition with a maximum rate of weight loss at 286 and 456 C are observed during the thermal conversion of sapropel of organo mineral type. The process of thermal conversion of sapropels in the air stream is characterized by a number of stages, including thermal decomposition of the OM and the subsequent oxidation of the formed heavy organic products. It was established by XRD method that the mineral part of sapropel from Barchin lake consist of low magnesium calcite (up to 80 wt. %) which dissociates in the temperature range 708-778 C, with a maximum rate of mass loss 2.3 and 3.2 wt. %/min., at 751 and 765 C, respectively.