Red mud recycling

In parallel with the increase of consumer demands, rare earth elements (REE) have became raw materials of ever increasing value, their use is extremely varied and they play a key role in many industries. In accordance with our current knowledge they can not be replaced with other substances. Their main field of utilisation is high-tech industry, but they are also used in the manufacturing of permanent magnets, catalysts, optical cables, lasers and light amplifiers — just to name a few.

As the REE mines get closer to exhaustion, recycling is gaining increasing attention in this area too. A separate industry emerged for making used electronic devices and rare earth magnets recyclable. There are many reusable rare earth elements in the by-products of aluminum and uranium production plants too.

Red mud is a by-product of aluminum production. Alumina is produced from crushed and milled bauxite using alkali additives, then alumina is reduced to aluminum by electrolysis. Red mud is a waste produced during the alkaline leaching of bauxite. It was named after the consistency and distinctive reddish colour of the sludge, the latter feature being caused by the iron oxide content of bauxite.

Similarly to iron oxide, red mud contains a large (3% to 50%) proportion of amorphous silicon dioxide (SiO2), and 10% to 20% aluminum oxide (Al2O3). Special attention must be given to the titanium dioxide (TiO2) content (1% to 25%), and to the presence of so-called light rare earth elements (LREE). The chemical composition and concentration of the latter depends on the finding place of the bauxite to be processed. The bauxite occurring in our country has almost twice the average REE content. Lanthanum, cerium, scandium and yttrium content in the average red mud usually is at the order of 100mg/kg.

In the near future a candidate for economically exploitable REE raw material is red mud, and we already have made concrete research and development (R&D) steps in this field: we started to study foreign specialty literature in 2002, started going to conferences of this kind and negotiating with worldwide recognised red mud experts. Our R&D team identifies red mud components and chemical structure by technical tests. In 2015 we signed a cooperation agreement with universities and research institutes for carrying out technological research in order to identify as soon as possible any technology that can economically extract valuable raw materials from red mud.

In parallel with the increase of consumer demands, rare earth elements (REE) have became raw materials of ever increasing value, their use is extremely varied and they play a key role in many industries. In accordance with our current knowledge they can not be replaced with other substances. Their main field of utilisation is high-tech industry, but they are also used in the manufacturing of permanent magnets, catalysts, optical cables, lasers and light amplifiers — just to name a few.

As the REE mines get closer to exhaustion, recycling is gaining increasing attention in this area too. A separate industry emerged for making used electronic devices and rare earth magnets recyclable. There are many reusable rare earth elements in the by-products of aluminum and uranium production plants too.

Red mud is a by-product of aluminum production. Alumina is produced from crushed and milled bauxite using alkali additives, then alumina is reduced to aluminum by electrolysis. Red mud is a waste produced during the alkaline leaching of bauxite. It was named after the consistency and distinctive reddish colour of the sludge, the latter feature being caused by the iron oxide content of bauxite.

Similarly to iron oxide, red mud contains a large (3% to 50%) proportion of amorphous silicon dioxide (SiO2), and 10% to 20% aluminum oxide (Al2O3). Special attention must be given to the titanium dioxide (TiO2) content (1% to 25%), and to the presence of so-called light rare earth elements (LREE). The chemical composition and concentration of the latter depends on the finding place of the bauxite to be processed. The bauxite occurring in our country has almost twice the average REE content. Lanthanum, cerium, scandium and yttrium content in the average red mud usually is at the order of 100mg/kg.

In the near future a candidate for economically exploitable REE raw material is red mud, and we already have made concrete research and development (R&D) steps in this field: we started to study foreign specialty literature in 2002, started going to conferences of this kind and negotiating with worldwide recognised red mud experts. Our R&D team identifies red mud components and chemical structure by technical tests. In 2015 we signed a cooperation agreement with universities and research institutes for carrying out technological research in order to identify as soon as possible any technology that can economically extract valuable raw materials from red mud.