高磷鲕状赤铁矿金属化还原焙烧—磁选—熔分新工艺研究

STUDY ON INNOVATIVE PROCESS OF HIGH PHOSPHORUS OOLITIC HEMATITE ORES PROCESSED BY METALLIZED REDUCTION ROASTING AND MAGNETIC SEPARATION AND MELTING SEPARATION

针对高磷鲕状赤铁矿中有价组元铁与杂质元素磷、硅、铝的分离难题,提出了低温选择性金属化还原—磁选—熔分处理新工艺,添加复合促进剂强化还原并促进金属铁微粒迁移、聚集、长大。研究了焙烧温度、促进剂用量、煤量、焙烧时间等条件对焙砂磨矿磁选后精矿铁品位、铁回收率及脱杂效果的影响。结果表明,添加剂对铁的富集及脱杂影响显著。优化的焙烧工艺条件下,原矿加入6%促进剂、25%的煤,975℃下恒温焙烧150 min,焙砂中铁主要以单质铁呈棒条状、蠕虫状产出,利于磨矿解离;磷仍主要以磷灰石存在;焙砂经磨矿—磁选,可获得含Fe 86.77%、P0.20%、Al_2O_3 1.81%、SiO_2 3.86%的精矿类海绵铁粉,Fe回收率>88%;类海绵铁粉在1 550℃下熔分,可以得到含磷小于0.01%、含铁大于99%的优质铁水,全流程Fe回收率>85%,杂质磷、硅、铝脱除率>99%,实现了铁的高效回收和铁与磷、硅、铝组元的深度分离。

Focusing on the intractable issue of the separation of the valuable element （iron） and impurity elements（ phosphorus, silicon and aluminum） from the high phosphorus oolitic hematite ores, this paper de- velops a new technology including selectively metallized reduction in low temperature and magnetic separation followed by melting seperation, adding composite promoters to improve reduction and promote metallic iron par- ticles migration, accumulation and growing. Through the examinations of the influences of roasting temperature, roasting time, dosage of promoters and reducing agent （coal） on the impurities removal, the grade of Fe and the Fe recovery in the magnetic-seperation concentrate, the results indicate that annexing agent has significant effects on iron enrichment and impurities removal. In the optimum process parameters of the raw ore reduction roasting time 150 min at 975 ℃ with 6% promoters and 25 % coal, iron which is bar strip and vermicular,mainly existed in the elemental form, phosphorus still existed as apatite. The calcine was processed by grinding and magnetic seperation to get a kind of spong iron concentrate with 86.77% Fe, 0.20% P,1. 81% A1203 and 3.86% SiO2, the Fe recovery being more than 88%. Next, spong iron concentrate re- passed melting seperation at 1 550 ~C , quality molten iron with P 〈 0.01% , Fe 〉 99 % could directly be pr- duced. The iron recovery of the whole process is more then 85 % , the phosphorus, aluminun and silicon impu- rity removal rate more then 99%. This new technology can efficiently recovery iron and effectively achieve the seperation of iron and phosphorus, silicon, aluminum.