(1. 東北大學(xué) 冶金學(xué)院，沈陽 110819；
2. 東北大學(xué) 多金屬共生礦生態(tài)化冶金教育部重點(diǎn)實(shí)驗(yàn)室，沈陽 110819)
摘 要: 為了闡明燒結(jié)法生產(chǎn)氧化鋁過程中堿對硅酸二鈣燒結(jié)行為的影響，采用熱重-差熱分析、X射線衍射、傅里葉紅外光譜、掃描電子顯微鏡等方法研究Na2O存在下不同燒結(jié)制度對硅酸二鈣(C2S)燒結(jié)過程中的物相轉(zhuǎn)變、晶體結(jié)構(gòu)和穩(wěn)定性的影響，從而為低鈉石灰燒結(jié)法提供理論依據(jù)。結(jié)果表明：在CaO-SiO2二元系中，燒結(jié)產(chǎn)物主要物相為γ-C2S；在CaO-SiO2-Na2O體系中，堿的存在使CaCO3分解溫度降低，燒結(jié)產(chǎn)物主要物相為β-C2S，Na2O起到助熔劑和改變C2S晶型的作用。在Na2O存在的條件下，燒結(jié)產(chǎn)物中β-C2S和γ-C2S紅外光譜特征峰分別為845 cm-1和930 cm-1。提高燒結(jié)溫度和延長保溫時(shí)間，促進(jìn)了塊狀β-C2S向呈顆粒狀γ-C2S轉(zhuǎn)化，β-C2S含量逐漸減少，γ-C2S含量逐漸增多，使得燒結(jié)產(chǎn)物結(jié)晶度升高；同時(shí)使燒結(jié)產(chǎn)物在堿溶液中的穩(wěn)定性提高，γ-C2S固溶體比β-C2S固溶體更穩(wěn)定。
關(guān)鍵字: 硅酸二鈣；燒結(jié)過程；物相轉(zhuǎn)變；晶體結(jié)構(gòu)；穩(wěn)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
