Measurements of the gasification rate of chars from lignite with admixtures by steam or CO2 showed that the admixtures of polymers, celluloses and wood reduce reactivity of resulting chars. The decrease of reactivity significantly manifests itself at both 800 °C and 900 °C. This is caused mainly by lower inner surface area which resists the gasification reactions. This negative phenomenon can be compensated by addition of magnetite, which acts as Fe-catalyst of the reactions of chars with steam as well as CO2 and accelerates the gasification. Through the isoconversional analysis, it was proven that the presence of magnetite significantly lowers the effective activation energy of these reactions, thus accelerating their course. The measurements of the reaction rate showed that it leads to a two- or three-fold acceleration of gasification., Pavel Straka., and Obsahuje bibliografii