Research On Improving The Converter Dust Cold-press Pellets’ Strength Of Binder

Converter dust is one of the metallurgical dust that generated during the production of steel-making and can be recycled as a secondary resource because of its high iron content (TFe>50%). As briquette pellets’strength is not enough and even chalking under conventional treatment process of converter dust, this paper adds special binder to solve this problem. First, the converter dust cold-press pellets’physical and chemical properties were studied by using common binder CMC, water glass, wooden-calcium and molasses. Second, the converter dust cold-press pellets’ chalking mechanism was analyzed by studying the thermodynamics and molar volume, and directly to the converter dust preparation of cold pellets without digestion was proposed. Afterwards, the press pellets’experiment was carried out by using NaHC03, NH4HCO3, (NH4)2CO3. Based on the results of above experiment, compositing a new binder of converter dust cold pellets dedicated, and testing the N’s consolidation effect. The result shows:(1) Using normal binder to processing converter dust cold-press pellets, consolidation pellets chalking phenomenon is obvious, and green pellets’ strength is not very different.(2) Converter dust cold-press pellets at room temperature for 24h consolidation occurs chalking mainly resulted by CaO digestion result to volume expansion.(3) Proposing using contains [CO3-] substance to consolidation CaO in the converter dust and need two requirement:① can react with CaO. ② the molar volume between the reactants and generation phrase should not be increased.(4) Using NaHCO3, NH4HCO3, (NH4)2CO3 offering [CO2-3] to consolidation CaO in order to solve the consolidation pellets’chalking is feasible. NH4HCO3 and (NH4)2CO23 addition more than 6%, the chalking can be eliminated.(5) Binder N can solve the converter dust cold-press pellets’ chalking and improve the consolidation pellets’strength significatively. Under the water addition 6% and the pressure is 30MPa, when N addition is more than 1.5%, the consolidation pellets had no chalking. When N addition is 4%, the consolidation pellets’ compress strength can reach to 1124N/per, the drop strength can reach 5.8 times/2m. The amount of water added should be 6% to 7%. N consolidation time need at least 11h.