Document Type


Publication Date

Winter 1-2014


The production of ceramic tiles and to a lesser extent flat dinner ware and pottery is increasingly being done by firing in roller kilns. These kilns offer several advantages over conventional tunnel kilns: lower fuel consumption, computer controlled firing curves, low maintenance due to lack of kiln cars, rapid firing cycles of less than one hour and the possibility of shutting down the kiln on short notice.1 One recurrent problem in the operation of such kilns is the periodic need to grind the kiln rollers. These are usually fabricated from high alumina clays and are continuously contaminated by depositions of alkali salts by condensation from the vapour phase. These latter salts, in turn, arise from some additions made on the original ceramic body recipe to impart some specific properties. In an average plant using one or two such kilns, the monthly product of grinding will consist of several tons of fine powder that usually accumulates within the plant premises as stock piles. This represents an extremely high ecological hazard as such powder, if inhaled for long periods, can lead to serious lung problems such as silicosis