Abstract

A. ROCHA, Jaime  and  A. LLANOS, Gustavo. Corrosivity of the atmosphere in the places of interest to the Evaporite Resources Projectin Southern Bolivian Highland. Rev. Met. UTO [online]. 2012, n.32, pp. 36-43. ISSN 2078-5593.

Based on a research project agreed between IIMETMAT-UMSA and GNRE- COMIBOL, four stations were installed to determine the corrosivity in the working area of the project: Exploitation of the Evaporite Resources of Bolivia, in order to provide useful information for the metal selection and protective coatings to be used in installations exposed to weathering. The stations for metal exposure and contaminants determination were installed in the villages of Llipi (Uyuni), Tauca (Coipasa) and within the two salt lakes. During the testing development, and due to the flood in the Coipasa Salt Lake, the station installed within the salt lake was missed, so that the results correspond to the three stations still in operation. The results obtained in the first year of exposure, show that despite the very similar weather behavior in the three stations (CW environments according to Koppen), the increased deposition of chlorides in the station located inside the Salar de Uyuni favors higher corrosion rates in the metals used for characterization (steel, aluminum, copper and zinc). Natural passivation of metals by formation of stable oxide layers seems to be influenced by the presence of chlorides, with copper being the only one that showed initiation of passivation with formation of stable "patinas". The ratings according to ISO 9223 for the selection of metal and protective coatings, show that for Uyuni 1 station (Llipi), and Coipasa 1 (Tauca), vary between C2 and C3 (low to medium), and C3 to C4 (medium to high) for Uyuni 2 station (Salt Lake).

Keywords : corrosivity; category; Uyuni; Coipasa; Salt lakes; chlorides.