Application of an Ecological Surface Treatment for Aluminum Profile

Abstract

Once aluminium is extruded, in contact with oxygen, forms quickly an aluminium oxide superficial protector layer, which is not penetrated  by humidity, gases or polluting agents. This layer has a low thickness and is a bad base for painting anchorage. Through the chemical superficial treatment of the aluminium profile (degreased, deoxidized and cleaning), it is possible its preparation to el iminate the thin oxide superficial layer and dirty and to form a layer of better features. This process is carried out
submerging the profiles in the sour dissolution and in the cleaning dissolution (water from the aqueduct and also treated water, without  ions) to leave them clean and lastly it is carried out the surface passivation treatment, also called chemical conversion treatment, to obtain bigger penetration and stability of the paintings. The lacquered plant of aluminium, Lacalum, which is the only o ne of this type in the country, used to employ and old technology of chemical superficial treatment using watery solutions that contained hexavalents chromium ions, in order to form a protector layer on the aluminium profiles. This chemical treatment is very harmful to health, that why it was decided its substitution for a new
advanced and respectful with the environment technology of non-chromium treatment; as well as the installation of a treatment plant for the process residuals. In general, these improv ements allow obtaining
a better product with the smallest impact to the environment as possible, and better in social aspect, thanks to the humanization of the work, and also in economic aspect, because of the decrease of the production costs. In this work, specifications, that most be considered during this non -chromium superficial chemical treatment of the aluminium profiles, are given to obtain a later lacquered; as well as the improvements for the environment.