Verfahren zum Verfestigen von wasserhaltigem Rotschlamm

摘要

The invention relates to a process for solidifying water-containing red mud to give a firm solid substance which can be landfilled harmlessly. According to the invention it is proposed that a calcium-containing additive is admixed to the red mud so that the aluminium hydroxide and iron hydroxide contained in the red mud chemically react in the reaction mixture with the calcium of the additive to give sparingly soluble crystalline hydrate phases and the reaction mixture solidifies in the course of this binding of the water contained in the reaction mixture with formation of solid matter. According to the invention, the proportion of added hydraulic or latently hydraulic binder can be below ten per cent by weight or can be dispensed with completely. In addition, it is proposed to add pollutant-containing residues to the reaction mixture which are immobilised in the crystal lattice by incorporation of the pollutants during the solidification. The red mud solidified according to the invention has good eluate properties and mechanical strengths so that it is suitable for surface tipping.