Several alkaline baths are used to prepare aluminum pieces before they are
anodized, and after certain operation times, they have to be renewed. Usual
ly, spent baths are neutralized with acid effluents, doubling the cost, the
treatment, and the loss of the aluminum and caustic soda content. In this
paper, the synthesis of 13X zeolite is proposed as a recovery process. The
aluminum content is recovered in this zeolite, which has applications in th
e formulation of detergents, and a solution of caustic soda and silicate is
obtained as a byproduct that could be reused in new synthesis processes or
other alkaline operations. The reaction temperature and time were selected
through an initial series of experiments, and the molar ratios that define
the batch composition were optimized through experimental design.