Feed processing for improved alumina process performance

A process for the treatment of an alumina process feedstock prior to transferring the treated feedstock to an alumina process for extracting refined alumina from the treated feedstock, which treatment process includes the following steps:

• (a) heating the alumina process feedstock in a highest temperature stage to a temperature of 400° C. to 650° C. by direct contact with combustion gas, and
• (b) cooling the heated feedstock to a temperature at which said heated feedstock is suitable for being handled and fed to the alumina process;
• which process further includes controlling the contact time of the alumina process feedstock at temperatures in the highest temperature stage in step (a) to ensure decomposition of alumina trihydrate and alumina monohydrate present, by dehydration, while not:
• (i) forming alumina monohydrate from alumina trihydrate, or
• (ii) reducing residual bound water to a level such that extraction is adversely affected, or
• (iii) allowing sufficient time for contact of the alumina process feedstock with water vapour such that a slower, water vapour-dependent loss of extractability is experienced;
• and which process further includes limiting the heat input into the highest temperature stage of the process by ensuring that a main thermal load associated with thermal dehydration of the alumina process feedstock is taken up in a stage or stages prior to said highest temperature stage, into which combustion gas, at a temperature above that of the combustion gas of the highest temperature stage, is added.