铁尾矿制备烧结砖和陶粒的研究

发布时间：2018-03-25 15:41

  本文选题：铁尾矿　切入点：粉煤灰　出处：《南京理工大学》2015年硕士论文

【摘要】：铁尾矿是铁矿石选取铁精矿后排放的一种工业固体废弃物。随着钢铁工业的快速发展,铁尾矿的排出量越来越多。对铁尾矿的处理已经成为矿山企业的发展的包袱。利用铁尾矿制备建筑制品已成为尾矿再利用的研究热点。本文在系统的分析铁尾矿的基本特性的基础上,以铁尾矿作为主要原料,研究制备烧结砖和烧胀陶粒的工艺,并对得到的烧结砖和陶粒的性能进行分析。研究内容和结果如下：1)系统的研究铁尾矿的基本特性。铁尾矿的主要矿物组成为斜绿泥石((Mg, Fe)6(Si, Al)4O10(OH) 8)、方解石(CaCO3)、石英(Si02)、赤铁矿(Fe203)和黄铁矿(FeS2)等。该尾矿中硅含量偏低,铁和钙的含量偏高。铁尾矿中铁的含量偏高是由于铁尾矿含有斜绿泥石、赤铁矿和黄铁矿造成的；钙的含量偏高是由于铁尾矿含有方解石造成的。铁尾矿中斜绿泥石的存在使得铁尾矿具有较好的可塑性。2)以铁尾矿为主要原料制备烧结砖,对得到的尾矿砖相关性能进行测定。结果显示,添加少量的粘土或粉煤灰能有效减小烧结尾矿砖的体积密度,添加粉煤灰对体积密度的降低效果更明显。在烧结温度为900℃～1000℃的范围内,添加少量粉煤灰的尾矿砖的吸水率在13-18%之间,抗压强度均大于15MPa,体积密度在1.8 g/cm3-2.0 g/cm3之间,体积收缩在0.5～2.0%之间,质量损失在6.0～10.5%之间。烧结砖的主要的矿物成分为透辉石(Ca(Mg,Al)(Si,Al)2O6)、钙长石((Ca,Na)(Si,Al)4O8)、硬石膏(CaSO4)、赤铁矿(Fe203)和石英(Si02)。这些新生成的矿物相是烧结强度的主要来源。通过对烧结尾矿砖微观形貌分析可知,添加粉煤灰的烧结砖的断面上具有更多的孔隙。3)铁尾矿中的Si02含量偏低,助熔剂氧化物(尤其是Fe203和CaO)的含量偏高,不能满足制备烧胀陶粒的化学组成。通过添加石英粉和粉煤灰来调整配方中Si02、A1203和助熔剂组分三者的配比使混合料满足制备烧胀陶粒的化学组成。研究结果表明,烧结温度在1210℃-1230℃范围内,保温时间在10-20min范围内,制备的配比为铁尾矿占30%,石英粉占10～30%,粉煤灰占40～60%的陶粒均为膨胀陶粒,其膨胀系数均大于1。所得到的膨胀陶粒的堆积密度均小于0.8g/m3,表观密度均小于1.2g/cm3,所得到的陶粒均可称为轻集料。所得到的陶粒的吸水率都很低,这是由于陶粒表面产生一层致密的釉质层造成的。对陶粒进行物相分析得到陶粒的主要物相为钙长石((Ca,Na)(Si,Al)4O8)、赤铁矿(Fe203)和石英(Si02)。通过对陶粒的SEM形貌分析可知,陶粒内部玻璃化现象明显且内部存在独立的封闭气孔。
[Abstract]:Iron tailings are a kind of industrial solid waste discharged from iron ore concentrate. With the rapid development of iron and steel industry, The treatment of iron tailings has become a burden to the development of mining enterprises. The preparation of building products from iron tailings has become a research hotspot of tailings reuse. In this paper, the systematic analysis of iron tailings has been carried out. Based on the basic characteristics of. Using iron tailings as the main raw material, the process of preparing sintered brick and fired expanded ceramsite was studied. The properties of the sintered brick and ceramsite obtained are analyzed. The contents and results of the study are as follows: 1) the basic characteristics of iron tailings are studied systematically. The main mineral composition of iron tailings are clinopyrite, Fe _ (6Si), Al _ (4) O _ (10) OH) _ (8), calcite CaCO _ (3), quartz Si _ (02) ~ (2). Iron ore (Fe203) and pyrite (FeS2). The content of silicon in the tailings is relatively low. The content of iron and calcium in iron tailings is higher than that in iron tailings because iron tailings contain clinachlor hematite and pyrite. The high content of calcium is caused by the iron tailings containing calcite. The existence of clinochlore in the iron tailings makes the iron tailings have good plasticity. 2) using iron tailings as the main raw material to prepare sintered bricks, The results show that adding a small amount of clay or fly ash can effectively reduce the bulk density of sintered tailing bricks. The effect of adding fly ash on the reduction of bulk density is more obvious. In the range of sintering temperature of 900 鈩，

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