The hot rolling sludge is formed by the adhesion of the oxide scale and lubricating oil, etc. which fall off during the hot rolling process of the billet and precipitate in the advection tank with the turbid circulating water. The total iron content of the sludge is high. However, due to its high oil content, it is difficult to use directly, and long-term open storage will cause idle iron resources and environmental pollution.

  Yang Dazheng, head of the research group and doctor of Angang iron and Steel Research Institute, said that in 2015, after the implementation of the new "environmental protection law", Angang Group listed the treatment of hot rolling sludge as a major scientific research topic, and the research and development team was established by the Institute of environment and resources of Angang iron and Steel Research Institute. The research group broke through the traditional hot-rolled sludge roasting or cleaning technology concept at home and abroad, and adopted the hot-rolled horizontal flow tank water stirring air floatation technology, which can effectively inhibit the production of hot-rolled sludge. On the basis of the success of the pilot test, the R & D team developed the on-line air floatation oil removal technology and equipment for the advection tank of Angang 1780 line, and began its industrial application. Up to now, the equipment has been in stable operation for more than 3 years, the average oil content of hot rolling sludge has decreased significantly, and the cumulative efficiency has reached 131 million yuan. Practice has proved that the technology has the characteristics of less investment, low cost, no secondary pollution and remarkable economic and social benefits. In May 2019, the technology was successfully applied to the Beidagou sewage treatment project of Angang, and will be applied to the advection pool of 1700 hot rolling production line in 2021.

  The application prospect of hot rolling sludge treatment technology is broad in the future. At present, three domestic iron and steel enterprises have reached an intention to promote this technology with Angang. This environmental protection technology will become a new benefit growth point of Angang.