Barley husk and barley straw ashes have high sintering tendencies and low melting temperatures,
which may cause severe ash related operational problems during combustion of the two fuels. XRD
analyses results indicate that silicate-alkali chemistry may play a critical role in initiating and enhancing
the barley straw and husk ashes sintering at elevated temperatures. Formation of low temperature melting
potassium rich phosphates may also be a possible cause of the low sintering temperatures of the barley
husk ash. Addition of kaolin and calcite significantly increased the sintering temperatures of barley straw
and husk ashes. In terms of kaolin addition, new high melting temperature potassium aluminum silicates
were identified from the sintered mixture of ash-additive, which may explain the improvement of the
barley straw and husk ashes sintering at high temperatures. On the other hand, the dilution effect was
supposed to be the main reason related to prevention of the two ashes sintering at elevated temperatures.
In addition, the calcium provided by calcite may also participate in barley straw and husk ash formation
and transformation processes, which may alter the ash chemistry, with formation of more high
temperature melting calcium silicates.