Feb 27, 2020 With rotary kilns with heat recovery the specific fuel energy consumption is typically more than 4 GJ/t, thereby representing a large part of the production cost for the alumina. In 2014, ETI Aluminyum commissioned Outotec to design a calciner capable of producing both smelter grade alumina (SGA) and ceramic grade alumina (CGA), which requires ... Rotary kilns systems have evolved considerably in form and complexity over the last 120 years, but the kilns themselves have certain common features. This page lists these and describes their evolution. Rotary kiln terminology. The Kiln Shell. The shell of the kiln is made of mild steel plate.