Study On Technology Of Injection Of Light-Burned Dolomite Powder During Material Mixing Of Sintering Process

Adding light-burned dolomite is significant to the quality and performance of sinter. In recent years most of the studies and practices domestic and overseas are focusing on the performance of sinter adding light-burned dolomite. Corelational research shows that injecting light-burned dolomite is benefit to the quality and economic indicator of sinter, while the method of injecting light-burned dolomite is studied and adopted only in a few developed countries. In our country, the material sticking and wastage of light-burned dolomite is on the high side. So the study on injecting light-burned dolomite to sinter mixture has important significance to improve the quality economical efficiency of sinter and reduce the wastage of flux and production cost in our country. Based on the raw material in Chongqing Iron and Steel Company(CQISCO),using full-factorial experiments method, the effect of the adding method, addition amount, injecting location and water addition quantity on mixing, sinter strength and metallurgical property is studied in the paper. The tech method and parameter of injecting light-burned dolomite into material mixing of sintering is proposed. The structure, form and comprehensive properties of sinter under different tech conditions are studied.The test shows: adding light-burned dolomite by injection can improve the quality of mixture and reduce the sticking rate by 60%, much better than by traditional mixing method. Rate of sinter acceptability can be improved by 2%. Cold strength is improved by 1% to 3% and its reducibility 1%. Adding water by 7.5%-8.0% allows the sinter palletizing to reach its perfect effect and has better blending and lower sticking rate. The quality, falling strength and drum strength are also having good performance. When the amount of injection being 4.6%, the indicators performance best. The falling strength is 83.80%, drum index is 73.10% and reducibility is 91.92%. Through the structural analysis of sinter, the magnetite and calcium ferrite are the majority of sinter, especially the melting corrosion structure, when the amount of injection is 4.64%. Most part of calcium ferrite is in the style of plate-type structure.Totally, the injection of light-burned dolomite is much more in favor of improving the economical efficiency and performance of sinter. Based on the condition in this paper, the appropriate amount of injection is 4.6 % and water is 7.5% to 8.0%. The injecting location is proposed in the process of first mixing.