FIELD: agriculture.SUBSTANCE: invention relates to methods for producing expanded vermiculite and can be used in the production of mixed fodder as a mineral supplement for animals and poultry from unenriched ore with an empty rock content of 15 to 85%. Method includes pre-drying, heating the raw materials in the flue gas stream and firing-swelling, respectively, in a rotating pre-heat drum, placed above one another at an angle to the horizontal, and a swelling drum. Drying, preheating and calcination-swelling are carried out in a fluidized bed, which is created by the flow of heated spent flue gas and by means of refractory lobes, arranged along the entire length in staggered order in said rotating drums, in the inlet pipes of which there are truncated cones, on the external surface of which the raw material is fed. Internal surface of the distributive truncated cone of the pre-heat drum is heated with the help of spent flue gases with a temperature of 500-600°C, coming from the swelling drum along the gas flow through the cyclone and the pipeline, the heating of the inner surface of the truncated cone of the swelling drum - by means of the burner burner to a temperature of 1,100-1,200°C with the temperature of heating of the processed raw material 600-700 ° C for the formation of expanded vermiculite, which is separated from the waste rock in the outlet branch pipe of the swelling drum by the air flow according to the difference in the volumetric weights and sail, and precipitated in the cyclone for cooling, with the air flow being created by the cyclone fan, and the production process of the expanded vermiculite is continuously carried out by circulating the heated spent flue gas of said drums in a closed system.EFFECT: invention makes it possible to improve the quality of the expanded vermiculite obtained, to ensure complete separation of the finished product from the waste rock, to rationally use the thermal energy of the waste gas stream and to improve the stability of the thermal regime.1 cl, 1 dwg