Abstract: A lower heat exchanger for preheating powdered raw materials has a system of cyclones. The exchanger is divided into a high temperature part and a low temperature part, mutually interconnected with an interconnecting tube of hot gas. Lowest member of low temperature part is a counter current shaft exchanger having an input under the level of hot gas output from the highest cyclone of high temperature part. Heated-up powdered raw material is transported from the low temperature part into the high temperature part by a transport tube, to which the hot gas stream is led. To this stream, powdered raw material from the output of counter current shaft exchanger is led. To the output tube arranged between the input chamber of a rotary kiln and the first cyclone of high temperature part, the inputs for fuel, combustion gas, hot gasses, and/or precalcined raw material are ended.

Abstract: The cyclone heat exchanger according to the invention comprises a set of cyclones for preheating powdered raw material. The set of cyclones is divided into a high temperature part (1) and a low temperature part (2) mutually interconnected by a tube (4) with a return loop (40) which is located below the lever of lower cyclone (21) of low temperature part (2). The powdered raw material is transferred from the low temperature part (2) to the high temperature part (1) by means of a transport tube (50), fed with hot transporting gas. The high temperature part (1) and the low temperature part (2) are located in such a way, that the connection of the warm gas input (130) of the highest cyclone (13) of high temperature part (1) is located above the connection of warm gas input (210) of lower cyclone (21).

Abstract: An equipment for calcination for precalcining of powdered materials before their burning in a sintering equipment is inserted between the last but one cyclone (72) of connected cyclone exchanger (7) and the mixing channel (2), arranged over the input chamber (31) of connected rotary kiln (3) and connected to the input to the last cyclone (71) of cyclone exchanger (7) and it is composed from calcinating chamber (1), which have three parts—a working part (10), to which are connected the at least one air tube (6) and the at least one fuel input (5) and where this working part (10) and/or air tube (6) are further provided with input (4) of powdered material, and the upper part (11), which is provided with at least one interconnecting tube (110) serving for interconnecting with mixing channel (2) and lower part (12), which is provided with a removal tube (120) for interconnecting with the mixing channel (2).