4.0 CONCLUSION
The optimization of process variables in alumina dissolution from Ozoro
clay using hydrochloric acid has been studied in order to obtain optimum
conditions for alumina yield from the local clay. The influence of
calcination temperature, leaching temperature, stirring speed,
liquid-solid ratio and acid concentration on the yield of alumina from
the clay were considered in the study based on experimental design using
the central composite rotatable design of the Response Surface
Methodology. The second order polynomial regression equation was
appropriate for fitting the experimental data and 0.9209 was obtained as
the correlation between the predicted and experimental responses.
Calcinations temperature of 677.27oC; leaching
temperature of 65.18oC; acid concentration of
1.9mol/cm3; liquid-solid ratio of 10.36 and stirring
speed of 442.92rpm were the values of the process variables which gave
the optimum alumina yield of 80.07%.