(1. 东北大学 冶金学院，沈阳 110819；
2. 东北大学 多金属共生矿生态化冶金教育部重点实验室，沈阳 110819)
摘 要: 为了阐明烧结法生产氧化铝过程中碱对硅酸二钙烧结行为的影响，采用热重-差热分析、X射线衍射、傅里叶红外光谱、扫描电子显微镜等方法研究Na2O存在下不同烧结制度对硅酸二钙(C2S)烧结过程中的物相转变、晶体结构和稳定性的影响，从而为低钠石灰烧结法提供理论依据。结果表明：在CaO-SiO2二元系中，烧结产物主要物相为γ-C2S；在CaO-SiO2-Na2O体系中，碱的存在使CaCO3分解温度降低，烧结产物主要物相为β-C2S，Na2O起到助熔剂和改变C2S晶型的作用。在Na2O存在的条件下，烧结产物中β-C2S和γ-C2S红外光谱特征峰分别为845 cm-1和930 cm-1。提高烧结温度和延长保温时间，促进了块状β-C2S向呈颗粒状γ-C2S转化，β-C2S含量逐渐减少，γ-C2S含量逐渐增多，使得烧结产物结晶度升高；同时使烧结产物在碱溶液中的稳定性提高，γ-C2S固溶体比β-C2S固溶体更稳定。
关键字: 硅酸二钙；烧结过程；物相转变；晶体结构；稳定性
（1. School of Metallurgy, Northeastern University, Shenyang 110819, China;
2. Key Laboratory for Ecological Metallurgy of Multimetallic Mineral, Ministry of Education, Northeastern University, Shenyang 110819, China）
Abstract:In order to clarify the influence of alkali on the sintering behavior of dicalcium silicate in the production of alumina by the sinter process, the phase transformation, crystal structure and stability of dicalcium silicate (C2S) in the presence of Na2O during the high-temperature sintering process under different sintering conditions were investigated by TG-DSC, XRD, FT-IR and SEM methods, providing theoretical basis for the low-sodium lime sinter process. In the CaO-SiO2 binary system, the main phase of the sintered product is γ-C2S. In the CaO-SiO2-Na2O system, the decomposition temperature of CaCO3 is reduced by Na2O, and the main phase is β-C2S. Na2O acts as the role of flux and can alter the C2S crystal forms. In the presence of Na2O, the characteristic peak of infrared spectroscopy of β-C2S and γ-C2S in the sintered product are 845 cm-1 and 930 cm-1, respectively. The increase of sintering temperature and the extension of holding time promote the phase transformation of blocky β-C2S to granular γ-C2S, decrease the content of β-C2S, increase the content of γ-C2S, and increase the crystallinity of the sintered product. The stability of the sintered product in the alkali solution is improved, and the γ-C2S solid solution is more stable than the β-C2S solid solution.
Key words: dicalcium silicate; sintering process; mineral transition; crystal structure; stability
