Produção do cloreto de alumínio a partir de rejeitos de bauxite de mina Alumina Lda para o tratamento de água

Abstract

The processing of bauxite generates huge amounts of waste. O storage of this material causes serious environmental damage and requires extensive area at your disposal. Develop technologies that allow their reuse and reuse becomes an alternative. However, studies show that these tailings still contain aluminates that can be reused to extract gibbsite-o main precursor of the various aluminum compounds. The present work presents the use of bauxite tailings as a raw material for the synthesis of chloride aluminum for water treatment. Samples of bauxite tailings from the dam containment of tailings from the Alumina Mine, were first subjected to classification granulometric and mineralogical, then the samples were digested with hydroxide of sodium to extract the aluminum hydroxides contained in bauxite, whose concentration it varied between 2 to 4 M with temperatures between 60 to 100ºC; after digestion, the separation of the red sludge from the filtrate consisting mainly of aluminum aluminate sodium, then it was neutralized with a solution of hydrochloric acid, obtaining thus whitish solids rich in gibbsite, these were dissolved in a solution of hydrochloric acid to obtain aluminum chloride, to crystallize it, it was heated to solution obtained in the dissolution until a temperature close to 100ºC and finally, the efficiency of the coagulant produced in the water treatment was tested. The results obtained in microscopy and XRF showed that the fraction of 38 𝜇𝑚, is the richest in gibbsite, at a temperature of 100ºC, concentration of 2M of caustic soda showed a better yield in the production of aluminum chloride and its application in the water treatment proved to be very efficient in removing turbidity from water treated and causing small pH variations in it (TRADUÇÃO NOSSA).