Utilization of the Prepyrolyzed Technical Hydrolysis Lignin as a Fuel for Iron Ore Sintering

A promising direction of technical hydrolysis lignin utilization is metallurgical production, primarily iron ore preparation and blast furnace process. A significant potential is concentrated in the sintering process. In order to improve properties of lignin in the role of a fuel, and to remove, with the possibility of trapping, toxic substances, it is necessary to carry out preliminary pyrolysis. The effect of technical hydrolysis lignin of different pyrolization degrees on the iron ore sintering process and properties of the obtained sinter is experimentally studied. Initial lignin was subjected to preliminary heat treatment to the final temperature of 400, 600, 800 and 1000 ºС without air access. Sintering with the participation of pyrolyzed lignin has been carried out via lab-scale sinter pot. After sintering, the sinter strength and the macrostructure have been determined. The chemical composition of the sinter samples has been revealed by X-ray fluorescence analysis.As a result of the experiments, the possibility of replacing 25 % of coke breeze with lignin prepyrolyzed at 800 ºС has been determined. Under these conditions, the main indicators of the sintering process, such as vertical sintering rate, product yield and specific capacity of the lab-scale sinter pot, remain virtually unchanged. There is a slight decrease in the impact strengths and the abrasion strengths of the sinter. However, these figures remain at a technologically acceptable level. It should be noted that when using lignin as a sintering fuel, there is a tendency for some decrease in the iron content of the sinter produced with it. The study of the sinter macrostructure has shown an increase in the pore diameter when the partial replacement of coke breeze with lignin while with the increasing lignin pyrolysis temperature the pore volume increases.The studies has evidence the possibility of solving the urgent environmental issues of technical hydrolysis lignin utilization by applying it in the sintering process with preliminary ...