Optimization And Modification Of Semi-coke Blending For Conventional Cokemaking

China is rich in coals but not in metallurgical coking coal, The coking coal whichare the major sources for making metallurgical coke, account only27%of all availablecoals. The fine coking coal with a content of low ash and sulfur is shortage, and it’seconomically recoverable reserves is lower especially. This is not possible to sustain thedevelopment of ironmaking and steelmaking at present. Significant attention, therefore,has been attracted to address this urgent challenge. Activities include the research forthe improvement of the properties of metallurgical coke so as to prolong itswithstanding time in blast furnace and hence to reduce coke consumption rate, and theinvestigation for the development of alternative resources to replace the main cokingcoal. So, It is very important to study the application of semi-coke in cokmaking forenlarging the coking coal resources and reduce the cost of cokmaking.The test of modifiing semi-coke and blending for cokemaking were carried out in40Kg coke oven, Experimental results show that: the value of caking index(G),maximum thickness of colloidal layer(Y), Arnu-Audibert’s dilatometer (b）, Plasticrange and maximum fluidity of blended coal decrease with the increase of semi-coke.However it was improved significantly with the addition of ZBS modifying additive.The best improvement was achieved when0.10wt%of ZBS was mixed with thesemi-coke, Which caused M40and CSR to increase, M10to decrease. The quality of theresulted coke was very close to the index of the coke with original coking coal and theproduction requirements can be met.For exploring the prospects for semi-coke using the blast furnace in the future,Experimental investigation has been carried out on the influence of modified materialson semi-coke quality by GB/T4000-1996. It has been found through spraying5-12wt%ZBS solution, the CRI and CSR are improved obviously respectively. The CSR canreach to50%when ZBS solution concentration are8-10wt%.The compressive strengthof semi-coke are increased significantly, that the load-bearing capacity increases in blastfurnace. Compared with that without adding ZBS, Microstructure of semi-coke detectedby SEM has been changed, which improves thickness of pore wall and degree ofgraphitization of carbon. The semi-coke treated by ZBS solution can replace nutcoke for400m3blast furnace.