A review of Dolochar reuse methods (waste from sponge iron factories)

Background and Objective: Dolochar is the residual ash from the production of sponge iron in the process of direct reduction of iron ore by the coal-based method. In Iran, this waste is transported to the nearest landfill. However, these methods are a major environmental concern due to the fineness of the waste and the presence of heavy metals in its composition. The aim of the present study is to investigate the methods of reusing dolochar in order to solve the environmental problem and further use it as auxiliary materials in applications such as road construction and wastewater treatment. Materials and Methods: In depth investigation of the word “Dolochar” in Science Direct, SID, and MagIran databases showed that there is no long history of reusing it. Only 14 English articles were found, all of which were used in research; Therefore, the present article deals with the issue of reusing Dolochar in Iran for the first time. Results: By reviewing previous studies, reuse of Dolochar has been classified into five sections. Dolochar use in wastewater treatment (removal of copper, chromium, paint, phosphate, nitrate, surfactant), removal of chromium from mine effluent (more than 94%), as a synthesis gas, as a filter medium (three times better than sand filters) and it is also used in construction and road construction (alternatives to aggregates). Conclusion: The high capacity of Dolochar in waste absorption and wastewater treatment shows that it is necessary to reuse it in Iran instead of burying or leaving it in the environment.