Expanded clay

— the light porous construction material received by roasting of fusible clay. Has the form of oval or (more rare) than round granules. It is made also in the form of sand — ceramsite sand.

Depending on the mode of processing of clay it is possible to receive expanded clay of various bulk density (volume weight) — from 250 to 600 kg/m ³ above.

Roasting of clay is made in metal reels furnaces, with a diameter of 2-5 meters and up to 70 meters long. Reels are installed at a small angle, clay granules are filled up in the top part of the furnace, under the influence of gravity they come down to the lower part where the nozzle for combustion of fuel is established. Time of stay of granules in the furnace about 45 minutes. Sometimes use two-drum furnaces where drums are separated from each other by a threshold and rotate with different speeds. Similar furnaces allow to use less qualitative raw materials though at the exit quality of expanded clay does not differ or above received in one-drum furnaces.

It is used as a heater in the form of filling, and also for production of light concrete - a keramzitobeton. It is used in agriculture and a hydroponics.