AbstractRare-earth elements (REE) are viewed as 'critical metals' due to a complex array of production and political issues, most notably a near monopoly in supply from China. Red mud, the waste product of the Bayer process that produces alumina from bauxite, represents a potential secondary resource ofREE. Karst bauxite deposits represent the ideal source material forREE-enriched red mud as the conditions during formation of the bauxite allow for the retention ofREE. TheREEpass through the Bayer Process and are concentrated in the waste material. Millions of tonnes of red mud are currently stockpiled in onshore storage facilities across Europe, representing a potentialREEresource. Red mud from two case study sites, one in Greece and the other in Turkey, has been found to contain an average of ∼1000 ppm totalREE, with an enrichment of light over heavyREE. Although this is relatively low grade when compared with typical primaryREEdeposits (Mountain Pass and Mount Weld up to 80,000 ppm), it is of interest because of the large volumes available, the cost benefits of reprocessing waste, and the low proportion of contained radioactive elements. This work shows that ∼12,000 tonnes ofREEexist in red mud at the two case study areas alone, with much larger resources existing across Europe as a whole.
Effect of red mud addition on the corrosion parameters of reinforced concrete evaluated by electrochemical methods