Simulative Research On The Compressed Strength Of Coke And Pellets In The Lumpy Section Of Blast Furnace

Coal injection is one of the most important technical developments in recent years inthe blast furnace production. The cost of the coal powder is about the half of the coke butthe permutation ratio is over 0.8. The cost of the iron production can be obviouslydecreased by coal injection.With the rising of the coal rate, the coke rate has been greatly reduced presently. Thepenetrable quality of the charging column was worsened, the burthen of coke was raisedand the carbon loss rate was increased accordingly. In this case, more attention was paid tothe high-temperature strength of the charging. In this thesis, tests on the lumpy section inblast furnace using a simulating model and on the compressed strength of coke and pelletsafter reaction at real temperatures using a high temperature compressive testing machinewith adjustable atmosphere were completed. The mainly results were as follows:1. The carbon loss rate of coke in blast furnace lumpy section rose very slowly in theupper part below 950℃and much faster in the lower part above 950℃.2. In the indirect reduction section of blast furnace, the compressed strength of cokeand the temperature had a linear relationship.3. In the lower part of lumpy section, the compressed strength of coke was affected bytemperature and carbon loss rate, and decreased rapidly with the rising of temperature.4. The compressed strength of coke in the simulating model decreased about 75% andabout 37% of it was affected by the carbon loss rate. There was a linear relationshipbetween the compressed strength of coke and the carbon loss rate.5. The distribution of the pellets compressed strength in lumpy section was affectedby both temperature and reduction rate. It can be described roughly using beelines.Presently, strength at normal temperature is usually used instead of hot strength. Thereal properties of coke and iron ore under the condition in a blast furnace are difficult to beexactly characterized using it. The relationship between temperature, carbon loss rate andcoke compressed strength and the relationship between temperature, reduction rate andpellets compressed strength were researched in present work. Base on the studies, a betterway to evaluate the quality of coke and pellets were brought forward.