Abstract: Apparatus for treatment and making of construction materials and the like having a rotary kiln. Calcined material from the rotary kiln is reduced in size by driven rolls and delivered as free-flowing material at an upper end region to a vertical shaft kiln having peripheral walls inclined from the vertical no more than 3.degree. and diverging downwardly. A sidewall of the shaft kiln has perforations inclined downwardly for flow of hot gases into the shaft kiln in the general direction of flow of material downwardly in said shaft kiln. The treated material from the shaft kiln is discharged from a lower end region and transported therefrom by a grate system having heaters for heating the treated material thereon.