Advances in red mud dewatering and disposal technologies

Red mud is the number one environmental concern of alumina plants today. A typical alumina plant can produce upwards of a million tons of red mud slurry each year. The large volume and the causticity of the red mud slurry are the principal problems. The search for ways to reduce the cost of mud disposal and the advent of stricter environmental regulations has led to many advances in the technology of red mud dewatering and disposal. A history of these advances is presented. A review and comparison of vacuum filtration, deep thickeners, super-thickeners, and hyperbaric filtration is presented in terms of technology, economics, and environmental impact. Advances in red mud disposal are also reviewed and compared including transportation to the disposal site, deposition of the mud, landscaping and rehabilitation of the site.