(1. 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；
2. 東北大學(xué) 冶金學(xué)院，沈陽 110819)
摘 要: 為了降低燒結(jié)法生產(chǎn)氧化鋁配鈣量和提高生成硅酸鈣穩(wěn)定性，系統(tǒng)研究3CaO·2SiO2 (C3S2)在高溫?zé)Y(jié)過程中的生成動力學(xué)、轉(zhuǎn)變機(jī)理以及在鋁酸鈉溶液中的穩(wěn)定性。研究表明：在CaO-SiO2二元體系中，CaO和SiO2摩爾比(C/S)為1.5:1時(shí)物料的非等溫?zé)Y(jié)過程主要分為CaO·SiO2 (CS)和2CaO·SiO2 (C2S)的生成與轉(zhuǎn)化、CS和C2S轉(zhuǎn)化成C3S2以及C3S2分解為C2S.和CS三個(gè)階段；在1460 ℃保溫1 h時(shí)，燒結(jié)產(chǎn)物中C3S2含量達(dá)到最大，為75.6%；延長保溫時(shí)間促進(jìn)C3S2的生成，并降低C3S2的生成溫度。C3S2的生成反應(yīng)控制步驟為二級化學(xué)反應(yīng)控制，其活化能為339.67 kJ/mol，指前因子為1.31×109 s-1。燒結(jié)產(chǎn)物在鋁酸鈉溶液中的穩(wěn)定性隨著C3S2含量的升高而增強(qiáng)，硅酸鈣化合物的穩(wěn)定性順序?yàn)椋篊3S2＞C2S＞CS。
關(guān)鍵字: 硅酸鈣；固相反應(yīng)；動力學(xué)；穩(wěn)定性；燒結(jié)法
（1. Key Laboratory for Ecological Metallurgy of Multimetallic Mineral, Ministry of Education, Northeastern University, Shenyang 110819, China;
2. School of Metallurgy, Northeastern University, Shenyang 110819, China）
Abstract:In order to reduce the lime addition and improve the stability of calcium silicates in alumina production by the sinter process, the formation kinetics, transformation mechanism and stability of 3CaO·2SiO2(C3S2) during high- temperature sintering process were investigated. The results show that the non-isothermal sintering process can be divided into three stages in the CaO-SiO2 binary system with the CaO to SiO2 molar ratio (C/S) of 1.5:1, the formation and transformation of CaO·SiO2 (CS) and 2CaO·SiO2 (C2S), the transformation of CS and C2S into C3S2, and the decomposition of C3S2 into C2S and CS. The content of C3S2 in the sintered product reaches the highest value of 75.6% when the sintering temperature is 1460 ℃ and the holding time is 1 h. The prolonging of holding time can promote the formation of C3S2 and reduce its generation temperature. The formation process of C3S2 follows the second-order chemical reaction model, and the corresponding apparent activation energy and the pre-exponential factor are 339.67 kJ/mol and 1.31×109 s-1, respectively. The stability of the sintered products in sodium aluminate solution increases with the increase of C3S2 content, and the stability order of calcium silicate compounds is C3S2＞C2S＞CS.
Key words: calcium silicate; solid state reaction; formation kinetics; stability; sinter process
