Environmental features of oxidative refining of phosphorous hot metal in heavy-duty converters

The article discusses a new method for estimating the amount of dust emitted from the converter bath during oxygen blowing of phosphorous hot metal. This method allows one to determine how technological solutions and blast modes affect the environmental performance of the production process. The study identified the causes of increased dust emission and developed the solutions to improve the environmental performance of the plant. Dust and gas emissions from the converter shop fall into two categories: organized and disorganized. Organized emissions are captured at the outlet of the converter mouth, and disorganized emissions occur periodically during cast iron casting, scrap loading, metal and slag discharge. These emissions contain dust, heat, carbon monoxide, nitrogen and sulfur oxides, and aluminum fluorides. Resource-saving technology using inactive slag reduces emitting of dust and gases by using active foamed slag at the initial stage of blowing and reducing lime consumption. Matching the gas volume to the exhaust duct’s through-put reduces dust removal by 30 – 40 % and unorganized emissions by 83 %. Reduction of carbon monoxide emissions is achieved by increasing the rate of rise in the CO concentration to the ignition limits, followed by afterburning on the “flare” and organizing melting with a shortened first heating period. Reducing the phosphorus content of cast iron to 0.3 wt. % decreases lime consumption from 143 to 77 kg/t of steel,the duration of blowing and heats by 10 – 16 %, lime production and increases the productivity of converters. A comprehensive approach to reducing dust and gas emissions includes optimizing processes, introducing new materials and technologies, and monitoring and analyzing performance indicators. This improves the environmental situation and increases production efficiency.