Rotary lime recovery kilns typically have four refractory zones. These wet process kilns use chain systems in the charging area to dry the slurry feed. In the preheating zone, the md feed is heated in preparation for the burning zone, and refractories range from fireclay (40% Al2O3) brick up to 70% brick. 60% to 70% alumina brick linings are often used in preheating zones and burning zones of many lime recovery kilns. 60% alumina brick offer increased resistance to the expansive alkali reactions that can cause alkali spalling. Seneca 60P exhibits excellent alkali resistance, improved stability in the lining, and phosphate-bonding gives it good mechanical strength. Seneca 60P also maintains low corundum content for good resistance to fluxing by the lime charge. For more traditional one-component recovery kiln linings, Rescal 70D is offered.
For kilns that have not undergone improvements in heat exchange components, basic brick presents the capability for higher calcining temperatures. Greenfree 92 is a 1st generation magnesite-spinel refractory brick with a medium content of in-situ spinel. Greenfree KF which gives significantly lower shell temperatures due to improved thermal conductivity and Rescomag 85 is the best option for harsh conditions within the burning zone.