Industrial Waste
Valorization

Waste sludge generation is an inherent and inescapable eventuality in all metals and mineral processing industries. For instance, titanium dioxide manufacturing produces a huge amount of titanium-bearing sludge. This sludge typically contains 15% to 22% titanium dioxide (TiO₂) and approximately 30% to 38% ferrous oxide (FeO). Shockingly, for every ton of titanium dioxide produced, one ton of sludge is generated.

Similarly, in the aluminum industry, for every ton of aluminum produced, 2.5 to 3 tons of red mud residue are generated. Red mud is rich in valuable minerals, containing about 30% to 60% ferric oxide (Fe₂O₃), 16% to 19% aluminum oxide (Al₂O₃), and 4% to 16% titanium dioxide (TiO₂).

Despite the availability of such valuable minerals in both titanium sludge and red mud, these waste streams have largely remained unprocessed by titanium and aluminum plants. This is primarily due to the lack of sustainable technology or processes to effectively recover these valuables. As a result, these waste sludges have accumulated in ponds since the inception of these plants, causing significant environmental degradation to the soil and groundwater surrounding the storage sites. While some aluminum plants have attempted to use red mud in cement manufacturing, its use is limited as it can alter the basic characteristics of cement.