cement kiln is one kinds of calcining machine for calcining cement,limestone,kaolin and so on

A rotary kiln (cement kiln) is a pyroprocessing  device used to raise materials to a high temperature (calcination )in a continuous process.Materials  produced using rotary kilns include .

Cement Lime Refractories Metakaolin Titanium dioxide Alumina Vermiculite Iron ore pellets

They are also used for roasting a wide variety of sulfide ores prior to metal extraction.

Principle of Operation or rotary kiln (cement kiln )

The kiln is a cylindrical vessel, inclined slightly to the horizontal, which is rotated slowly about its axis. The material to be processed is fed into the upper end of the cylinder. As the kiln rotates, material gradually moves down towards the lower end, and may undergo a certain amount of stirring and mixing. Hot gases pass along the kiln, sometimes in the same direction as the process material (co-current), but usually in the opposite direction (counter-current). The hot gases may be generated in an external furnace, or may be generated by a flame inside the kiln. Such a flame is projected from a burner-pipe (or "firing pipe") which acts like a large bunsen burner. The fuel for this may be gas, oil or pulverized coal.

Construction

The basic components of a rotary kiln are the shell, the refractory lining, support tyres and rollers, drive gear and internal heat exchangers.

high grade cement kiln/limestone kiln