Bioleaching of industrial waste as pyritic ash from sulphuric acid plant: A biotechnological approach for metal recovery
Goal: Pyritic ash, an industrial waste, is a by-product formed as a result of roasting of pyrite ores. The waste is associated with several environmental issues. Over the years, many strategies have been adopted to utilize the pyritic ash waste. It is very interesting to note that the pyritic ash material contains considerable amounts of valuable metals like copper, zinc, cobalt, gold, arsenic etc. which can be recovered. Keeping in view of the present day research that is aimed at producing zero waste eco-friendly technologies, the present work is focused on providing a promising biotechnological alternative for the utilization of pyrite ash. Bioleaching using chemolithotrophic acidophilic microorganisms (in pure and mixed cultures) were used as a potential bioengineering tool for metal recovery from pyritic ash. Physico-chemical and Biological process parameters were evaluated from lab to semi-pilot scale bioreactor tests and conditions were established for efficient multi-metal recovery. The study offers several attractive environmental advantages as a bioprocess with future potential for industrial application.