Abstract: This invention relates to a a vertical shaft kiln (VSK) useful for manufacturing cement and other allied products, which comprises a rotary nodule feeder for feeding the raw materials, fitted above the kiln bed for uniform distribution of nodules of the raw materials, an air blower being placed at the base of the kiln for feeding air through a duct to a common air header having a plurality of outlet air ducts, the air duct being connected to an air cone placed inside an armoured shell of the VSK, the said air cone being provided with a grate assembly having a plurality of peripheral air slots, the air duct being connected to an air box placed above the said armoured shell, the said air box having perforations on the inside vertical wall, the air duct being connected to an air header having air entry nozzles placed in such a manner so as to supply air just below the sintering zone of the VSK, the air duct being connected to the chimney of the VSK, the said chimney being provided with a butterfly valve below th