Research On Blast Furnace Dust Binder In Preparation Process Of Metalized Pellets

The blast furnace dust is a kind of solid waste that produced in the process of ironsmelting, and it is secondary resource for it contains great amount of Fe and non-ferrousmetal, so recycling and using the dust comprehensively are significant to alleviate thesituation of resources in china, while the environment can be improved. But the dust isnot easily recycled to make pellets due to its complex components, so the binders appliedto blast furnace dust to make carbon-containing pellets should be developed.Physical and chemical characteristics of dust were investigated firstly. And theimpact of water and pressure on pelletizing of blast furnace dust was studied secondly.The experiment results showed that the strength of pellets can be improved bybinders, but different binder has different bonding mechanism of blast furnace dustcarbon-containing pellets. The pellets strength of low temperature can be improved bystarch binders and epoxy resin, while the strength of high temperature can be improvedby silicon-containing binders. But no matter what kind of binders are added, the highestpellets strength is only up to478N, which not meet the demands. Appropriate amount ofmagnetite are added to pellets for taking advantage of surplus carbon and improvingstrength. As20%of magnetite and sole binder, the strength of pellets don’t totally reachthe objective, but binders composed of corn starch and sodium silicate with proportionsof2%~3%can make the strength reach the objective, so does the binders composed ofcorn starch and organic silicon resin with proportions of3%~4%. As40%of magnetite,the both sole binders and compound binders can make pellets reach the objective.Mechanism showed that sodium silicate can become the bond film and precipitatesilicic acid gel to improve strength at high temperature. Additionally the reductionprocess of ferric oxides can be accelerated by sodium ion and it is conductive to raisepellets strength. While the corn starch can raise the low temperature strength of pelletsfor its characteristics. However it will disintegrate at higher temperature. The articleprovides theory and technology basis for comprehensive utilization of blast furnace dust.