Influence of calcium ferrite characteristics on metallurgical properties of high basicity sinter
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摘要: 烧结矿中主要粘结相矿物铁酸钙的含量、形态、结晶粒度等特征对烧结矿质量起着关键性作用。采用偏光显微镜对不同质量的现场高碱度烧结矿的矿相结构及铁酸钙特征进行了系统定量研究。结果表明:两种烧结矿金属相均以赤铁矿和磁铁矿为主,黏结相均为铁酸钙、硅酸二钙和玻璃质。不同之处是1#烧结矿以针状铁酸钙交织赤铁矿、磁铁矿形成的交织熔蚀结构为主;2#烧结矿以他形粒状磁铁矿与粘结相矿物相互结合形成的粒状结构为主。1#烧结矿中铁酸钙体积分数约为50%,形态多为针状,粒度范围主要为0.05~0.10 mm;对应的烧结矿还原性(75%)、低温还原粉化率(76.5%)和转鼓强度(81.6%)均良好。2#烧结矿中铁酸钙体积分数约为45%,形态多为板状、柱状,粒度范围主要为0.05~0.10 mm;对应的烧结矿还原性(59.35%)较弱、低温还原粉化率(25.21%)较低和转鼓强度(63.37%)较小。Abstract: The content, morphology and grain size of calcium ferrite, and the main binding mineral as well in sinter, play a key role in the quality of sinter. The mineral phase structure and calcium ferrite characteristics of high basicity sinter with different quality situation were studied systematically and quantitatively by using polarized light microscope. The results show that hematite and magnetite are the main metal phases of No.1 and No.2 sinter. The bonding phases are calcium ferrite, dicalcium silicate and vitreous. The difference is that the No.1sinter is mainly composed of interlacing corrosion structure formed by acicular calcium ferrite and magnetite. The No.2 sinter is dominated by granular structure formed by the mutual combination of allochthonous magnetite and binding mineral. The volume percentage of calcium ferrite in No.1 sinter is about 50%, and its shape is mostly needle shaped. The size range of diameter is 0.05~0.10mm. The corresponding sinter reducibility (75%), low temperature reduction degradation rate (76.5%) and drum strength (81.6%) show high values. The volume fraction of calcium ferrite in the No.2 sinter is about 45%, and its shape is mostly plate and column. The size range of its diameter is 0.05~0.10mm. The corresponding sinter reducibility (59.35%) is weak, the low temperature reduction degradation rate (25.21%) is low, and the drum strength (63.37%) is small.
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表 1 现场烧结矿主要化学成分
Table 1. Main chemical compositions of used sinter
% 编号 TFe FeO SiO2 CaO MgO Al2O3 TiO2 1# 55.1 8.7 5.42 11.28 2.83 2.48 0.12 2# 56.7 8.5 4.87 10.1 1.91 0.46 表 2 烧结矿的矿物组成及含量
Table 2. Mineral compositions and contents of sinter
% 编号 赤铁矿 磁铁矿 铁酸钙 硅酸二钙 玻璃质 残余CaO 硫化物 1# 30~40 15~20 45~50 5~10 少量 微量 2# 8~10 35~40 45~50 5~7 少量 ±1 微量 表 3 烧结矿的冶金性能
Table 3. Metallurgical properties of sinter
% 编号 还原性 转鼓指数 低温还原粉化率 1#烧结矿 75.00 81.60 76.50 2#烧结矿 59.35 63.37 25.21 -
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