Laboratory Evaluation of Electrokinetic Dewatering of Bauxite Tailings

The mining tailings disposal system is often associated to the construction of large retaining systems, either for the great volume of materials generated by industrial plants or for the impossibility or difficulty of grants for new disposal areas. Due to increasing demand, these impoundments have become much more significant, triggering considerable increase of risk associated to them. In this context, new techniques must be developed aiming to decrease the volume of tailings produced and the optimization of disposal systems for these materials, particularly in terms of systems including tailings dewatering techniques. An alternative solution consists in dewater and consolidate mine tailings under current intermittence, technique called electroosmosis. This paper presents the development of an electroosmotic cell to measure the electrokinetic flow and the consolidation process of fine tailings under specified boundary conditions. The tailings are generated by the process of treatment of bauxite from BPM (Bauxita Paragominas Mining/Brazil), which consist of fine-grained materials, with initial solid content of 31%. The results of this experimental study are analyzed and discussed based on the principles of electrokinetic theory and has shown that the proposed technique would significantly accelerate the consolidation process of fine tailings (an average solid content of 58% was reached, within a 12-hour period), besides providing adequate design parameters for field applications.