In modern preparation methods of oxidated (blown or semi-blown) bitumen qualities the air needed for the oxidation and the bitumen oil is brought into contact in a large volumed reactor (so-called bubble column technique). The drawbacks of the method are the safety risks because of the large oil and gas volume, the high oxygen content of the rest gas, a bad adjustability of the reaction and the reduced quality properties of the product because of the long retention time.

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