金川镍渣多组分综合利用研究
发布时间：2019-01-06 09:47
【摘要】：金属镍冶炼过程中会排放以FeO.SiO2为主要成分的工业废渣。全国累计堆存量超过4000万吨,每年新增约200万吨。镍渣中Fe含量为40%~45%,SiO2含量为32%~36%,MgO为1%~11%,CaO为1%~3%,并含有不同数量的镍、铜、钴、金、银等有价金属,是潜力极大的可再利用二次资源,但因为其矿物组成复杂,至今未得到有效综合利用,多以堆存的方式处理,不仅占用场地,且存在环境污染隐患,已经成为急需取得突破的课题之一。本文针对金川镍渣综合利用中存在的问题,提出将镍渣提铁和脉石综合利用相结合的技术思路,通过一次还原焙烧,同时得到直接还原铁与胶凝材料两种物质,实现镍渣全组分综合利用。还原焙烧实验在可控温度电阻炉中进行,还原过程碱度通过添加石灰调整,还原剂为煤粉。实验分别从还原剂加入量、还原时间、还原温度、石灰加入量、反应气氛等方面进行了研究。取得的研究成果如下:(1)热力学软件计算表明:硅酸二钙在低温下即可生成;850℃出现Ca3MgSi2O8,其稳定存在区域较小,900℃时消失;在1100℃时,Al2O3和CaO反应生成铝酸三钙;1350℃~1400℃时,游离氧化钙大量减少并与硅酸二钙结合成硅酸三钙,铁和硅酸三钙可以同时存在。(2)连续升温还原实验当物料粒度200目、还原剂配比15%、碱度为2.6、反应温度1480℃、反应时间40min条件下铁的还原率最高,可达62.9%。铁单质可通过湿法磁选分离,较佳磁选参数为粒度300目,磁场强度为先在3000Gs扫选,再进行1000Gs精选,铁回收率为78%。(3)连续升温还原实验可获得直接还原铁,但未得到胶凝组分C3S。分析其原因是在还原气氛下,镍渣中的Fe2+取代了部分Ca2+进入C3S晶格中,当熟料出炉冷却时,Fe2+又重新被氧化成Fe3+,Fe3+不能取代C3S晶格中的Ca2+,离子的迁移导致C3S结构不稳定而分解。因而提出将实验升温过程分为两段进行。(4)“两段法升温”第一段升温主要是还原FeO,反应温度定为800℃~1000℃,保温一定时间使FeO充分还原为铁单质,避免二价铁离子对生成C3S的不利影响。第二段升温温度定在C3S的生成温度区间1350℃~1500℃,以使物料充分反应生成硅酸三钙。实验得到的较佳参数为:第一段升温至1000℃,保温时间为40min;第二段升温至1480℃,保温时间90min;物料急冷至室温后可以同时得到铁单质与胶凝材料硅酸三钙与硅酸二钙。其中硅酸三钙占总物料的55%,铁的还原率为72%。通过不连续升温还原焙烧后的物料快速冷却后进行磁选分离,铁、镍、铜等易还原组分以直接还原铁合金形态存在可供电炉作原料,剩余组分转化成具有胶凝性能的粉状物料供矿山填充及水泥生产配料,实现了镍渣组分的综合利用,本课题研究成果可为相关行业提供参考依据。
[Abstract]:Industrial waste residue with FeO.SiO2 as the main component will be discharged during nickel smelting. The national accumulative reactor stock exceeds 40 million tons, adding about 2 million tons each year. The content of Fe in the nickel slag is 40% and the content of Sio 2 is 320.36%. The content of SiO2 is 320.The content of SiO2 is 32% and the amount of Cao is 1%, and the amount of valuable metals, such as nickel, copper, cobalt, gold, silver, and so on, is one of the most potential reusing resources. However, because of its complex mineral composition, it has not been used effectively, and it is mostly treated by stacking, which not only occupies the space, but also has the hidden trouble of environmental pollution, which has become one of the urgent problems that need to be broken through. Aiming at the problems existing in the comprehensive utilization of Jinchuan nickel slag, this paper puts forward the technical idea of combining the iron extraction from nickel slag with the comprehensive utilization of gangue, and obtains two kinds of materials, direct reduction iron and cementitious material, by single reduction roasting. The comprehensive utilization of nickel slag was realized. The reduction roasting experiment was carried out in a controlled temperature resistance furnace. The basicity of the reduction process was adjusted by adding lime, and the reducing agent was pulverized coal. The experiments were carried out from the aspects of reducing agent dosage, reduction time, reduction temperature, lime addition amount, reaction atmosphere and so on. The results obtained are as follows: (1) the thermodynamic software shows that dicalcium silicate can be formed at low temperature, the stable region of Ca3MgSi2O8, appears at 850 鈩，
本文编号：2402646
[Abstract]:Industrial waste residue with FeO.SiO2 as the main component will be discharged during nickel smelting. The national accumulative reactor stock exceeds 40 million tons, adding about 2 million tons each year. The content of Fe in the nickel slag is 40% and the content of Sio 2 is 320.36%. The content of SiO2 is 320.The content of SiO2 is 32% and the amount of Cao is 1%, and the amount of valuable metals, such as nickel, copper, cobalt, gold, silver, and so on, is one of the most potential reusing resources. However, because of its complex mineral composition, it has not been used effectively, and it is mostly treated by stacking, which not only occupies the space, but also has the hidden trouble of environmental pollution, which has become one of the urgent problems that need to be broken through. Aiming at the problems existing in the comprehensive utilization of Jinchuan nickel slag, this paper puts forward the technical idea of combining the iron extraction from nickel slag with the comprehensive utilization of gangue, and obtains two kinds of materials, direct reduction iron and cementitious material, by single reduction roasting. The comprehensive utilization of nickel slag was realized. The reduction roasting experiment was carried out in a controlled temperature resistance furnace. The basicity of the reduction process was adjusted by adding lime, and the reducing agent was pulverized coal. The experiments were carried out from the aspects of reducing agent dosage, reduction time, reduction temperature, lime addition amount, reaction atmosphere and so on. The results obtained are as follows: (1) the thermodynamic software shows that dicalcium silicate can be formed at low temperature, the stable region of Ca3MgSi2O8, appears at 850 鈩，
本文编号：2402646
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