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粉状铬矿经回转窑还原制取的还原球团用于矿热电炉冶炼高碳铬铁,可以改善炉况、增加产量、大幅度降低电耗,增加经济效益。试验确定了还原剂与铬矿混合磨料方式、最佳料粉细度、还原剂配入量、适宜的还原温度和还原时间等工艺参数。制备了抗磨性良好的生球团。得到的还原球团抗压强度500N/球、还原度>50％,能满足冶炼铬铁的工艺要求。研究确定镁铬铁矿在还原过程中转变形式为:(Mg、Fe)O·(Cr、Al、Fe)_2O_3→(Mg、Fe)O·(Cr、Al)_2O_3→MgO·(Cr、Al)_2O_3→MgO·Al_2O_3。铬矿还原球团的还原产物主要为(Cr、Fe)_7C_3,未被还原的MCr_2O_4及可以看到的少量Fe和Cr等。经浙江省冶金研究所在φ0.72×8.36m的回转窑内进行扩大试验,验证了我院提供的试验总结,在400kVA电炉上使用还原率高于50％的铬矿还原球团,铬铁冶炼电耗可由3600kWh/t降至2250kWh/t。
Powdered chromium ore reduction by the rotary kiln reduction pellets for the use of ore hot-electric furnace smelting high-carbon ferrochrome can improve furnace conditions, increase production, significantly reduce power consumption, increase economic efficiency. The experiment confirmed that the reducing agent and chrome ore mixed abrasive mode, the best powder size, the amount of reducing agent, the appropriate reduction temperature and reduction time and other process parameters. A good abrasion resistance pellet was prepared. The resulting reduced pellets compressive strength of 500N / ball, reduction of> 50%, to meet the smelting ferrochrome process requirements. The results show that the transition form of magnesian chromite is as follows: (Mg, Fe) O · (Cr, Al, Fe) 2 O → (Mg, Fe) O · (Cr, Al) 2 O 3 → MgO · (Cr, Al ) _2O_3 → MgO · Al_2O_3. The reduction products of chrome ore reduction pellets are mainly (Cr, Fe) _7C_3, unreduced MCr_2O_4 and small amounts of Fe and Cr which can be seen. After the Zhejiang Metallurgy Institute in φ0.72 × 8.36m rotary kiln to expand the test to verify our laboratory provides a summary of the experiment, the use of 400kVA EAF reduction rate higher than 50% chromium ore pellets, ferrochrome Smelting power consumption can be reduced from 3600kWh / t 2250kWh / t.