Viability of the use of pickling baths from aluminium surface treatment for synthesizing low Si/AI zeolites

Abstract

Currently, the European extruded aluminium profile industry generates 3.000.000 litres per year of waste liquors from the pickling and etching baths. There are two trends for their treatment: the precipitation of aluminium and its disposal in controlled landfills or their incorporation in the water treatment system of the plants. The former way wastes the possible recovery and the latter one increases the amount of produced muds which are one of the most important problems that this industry must face up. We propose the synthesis of low Si/Al ratio zeolites as recovery treatment. Real industrial pickling baths with their changing characteristics were used and zeolites fulfilling the specifications for their use in the formulation of detergents were obtained without the necessity of acting on the operation conditions of the plant that is the main factor when a recovery process is implemented in a working plant.