Possibility to use the red mud

Abstract

A strange environmental accident happened on the 4th of October, 2010, in Hungary. Hungary has declared a state of emergency in three counties following 600 – 700 m3 toxic red mud spill when a reservoir burst at an alumina plant in Ajka, 160 kilometers south-west of the capital, Budapest [1]. The red mud (bauxite residue) is a hazardous material, rank II, because of its pH = 1. 2 – 13. In Romania a similar factory functioned between 1965-2006 in Oradea, which annually produced 240.000 tons of alumina for ALRO Slatina. (This factory was then sold to the Russian Concern Ruski Alumini) [2]. When producing 1 tonne of alumina, 1.5-2 tones of red mud is resulted. During the more four decades of functioning at Oradea, an immense quantity of red mud resulted, which still exists in a storage and is still unused. Appears that the water of rain diluted the concentration of the alkalis, but a pH of 9.5 was determined. In this form the red mud can be tested as adjuvant in acid composts. For its usage in ceramic mixtures, destined to building materials, its neutralization is necessary with acid wastes for ex. in the vinegar or milk industry.