Scientists have turned harmful coal ash into an effective water purification reagent. The breakthrough technology solves two problems: the disposal of hazardous waste and the production of a useful coagulant.
Researchers from Russia and China have developed an innovative method for processing fly ash from coal-fired power plants. Now this waste becomes the basis for the production of polyoxychloride aluminum – a powerful coagulant used in water treatment plants. The method provides double benefits by reducing environmental damage and creating a useful product.
A coagulant is a substance that purifies water by causing tiny contaminant particles to stick together into large flakes. These flakes are then easily removed. The technology is based on the leaching process: with the help of hydrochloric acid, valuable elements – aluminum and iron – are extracted from the ash. After optimizing the process conditions, the scientists achieved recovery of 70% of the aluminum contained in the waste.
The resulting solution is then converted into a liquid coagulant. The key advantage of the new aluminum polyoxychloride was not only the high content of the active component, but also the safe level of heavy metals. In tests, the reagent proved its effectiveness, reducing water turbidity by almost 96%, which corresponds to the best commercial analogues.
It is important that the technology is virtually waste-free. The solid residue after processing, consisting mainly of silicon dioxide, can be used in the construction industry. Thus, the ash becomes fully valuable.
This development opens the way to large-scale and economical disposal of ash accumulated in huge quantities. The introduction of technology will not only purify water, but also significantly reduce the harmful impact of coal energy on the environment, closing the production cycle.
The material was prepared with the support of the Russian Ministry of Education and Science as part of the Decade of Science and Technology.
Source: @cdutek
Photo: Shutterstock
