Study On Optimizing Coal Blending Structure Of Reducing Ash Content Of Coke

The ash content of cokes is an important factor to determine the quality,and it has an important impact on blast furnace.In this paper,four metamorphic grade coking coals from Qingting mine in an enterprise were taken as an example.The ash content of coking coals from Qingting mine was washed to different range by varying degrees of coal cleaning procedure firstly.The properties of coking coals in different ash content were fully analyzed,including proximate analysis,caking property analysis,coal petrography analysis,ash constitution analysis and corresponding coke quality analysis.The influence of ash content of coking coals on its coking property was studied.Then 17 kinds of coal blending structure were determined,which were based on Qingting coals in different ash content range and the coking coals commonly used in the enterprise.And the quality of blending coals and the quality and microstructure of cokes made on 40kg pilot coke oven was analyzed.The aim of optimizing coal blending structure and reducing the ash content of cokes is achieved.According to this,ash content,cold strength and thermal property prediction models of cokes were established.The study shows that with the decrease of ash content of different coking coals,caking property is improved into different degree.Caking property whose caking property is better has a little improvement;but caking property whose caking property is worse is improved obviously.The strength of cokes from different coking coals has different change,the strength of cokes from coking coals whose caking property is better has a little change;but the strength of cokes from coking coals whose caking property is worse has much improvement.When the coking coals in different ash content were done coal blending replacing experiment,besides the ash content of blending coals and cokes is reduced,the caking property of blending coals and the quality of corresponding cokes changes irregularly with the decrease of ash content of Qingting 1/3 coking coals,fat coals and coking coals added.But the caking property of blending coals and the quality of corresponding cokes has much improvement with the decrease of ash content of Qingting lean coals added.According to the actual coal blending and coking production practice,the established coke models are down here as follows:A_d,J=1.5889A_d,M-2.8247 R=0.9004M₄₀=3.1792V_daf+1.0665G-100.7299 R=0.8042M₁₀=-1.2634V_daf-0.4279G+81.9831 R=0.9034CRI=1.5972V_daf-1.2970G-0.7015MCI+96.6119 R=0.8000CSR=-3.2201V_daf+2.0903G-0.5010MCI-37.4141 R=0.6901The prediction models established were tested by using correlation coefficient test,their correlation cofficients of R are all greater than their critical values.Therefore,the prediction models established have certain application value in the process of practical production.