Abstract

RANGEL CORDOVA, Agustín Alexander; ISARAIN CHAVEZ, Eloy  and  MALDONADO VEGA, María. Characterization and recovery of hexavalent chromium salts from a hazardous waste site. Rev. Int. Contam. Ambient [online]. 2015, vol.31, n.4, pp.427-437. ISSN 0188-4999.

The purpose of this study was to examine a diverse group of washing solutions for its use in the recovery of the industrial waste hexavalent chromium, in compliance with the Mexican regulation NOM-147-SEMARNAT/SSA1-2004. The recovery process consisted of a simple random sampling and a physical-chemical characterization with consideration to the high solubility of hexavalent chromium compounds. A test was performed which implemented five different washing solutions (water, sulfuric acid, citric acid, sodium hydroxide, calcium and hydroxide). This was followed by a factorial experimental design to optimize resources with a removal efficiency of 80 % and hence a recovery of 33 g/kg as CaCrO₄ (calcium chromate). Chromium hexavalent concentration in the leachate was quantified using UV-Vis spectrometry at a wavelength λ = 540 nm, while the salts recovered by evaporation were characterized using XRF analysis, leading to the conclusion that precipitate can be used as raw material, the main elements are Cr, Ca, Fe and Mg, and their concentration depends on the washing solution.

Keywords : chromium; wastes; leachate; treatment; recovery.