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.