Mineral Transform and Specific Heat Capacity Characterization of Blast Furnace Slag with High Al2O3 in Heating Process. Issue 3 (17th November 2020)

• Record Type: Journal Article
• Authors: Zheng, Haiyan; Liang, Lisheng; Du, Jinlei; Zhou, Shifa; Jiang, Xin; Gao, Qiangjian; Shen, Fengman
• Is Part Of: Steel research international. Volume 92:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-11-17
• Subjects: blast furnace slag with high Al2O3 -- mineral transform -- specific heat capacity -- w(MgO)/w(Al2O3) ratio; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.202000448
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : The specific heat capacity ( C p ) of blast furnace (BF) slag critically impacts BF smelting and reports on the C p of BF slag with high Al2 O3 are rare. Mineral transform and C p characterization of synthesized BF slag (CaO–SiO2 –MgO–Al2 O3 ) with high Al2 O3 in the heating process are herein discussed. Differential scanning calorimetry curves show a major exothermic peak at a low temperature and multiple endothermic peaks at elevated temperatures. The exothermic peak at approximately 920 °C appears when amorphous SiO2 (or SiO2 in silicate) becomes crystal SiO2 (or SiO2 in silicate). The endothermic peak between 1224–1254 °C is attributed to the reverse eutectic reaction, CaO·Al2 O3 ·2SiO2 + 2CaO·0.5MgO·0.5Al2 O3 ·1.5SiO2 → Liquid, along a eutectic line. CaO·Al2 O3 ·2SiO2 + MgO·SiO2 → Liquid + 2MgO·SiO2 (reverse peritectic reaction) or CaO·Al2 O3 ·2SiO2 + 2MgO·SiO2 → Liquid (reverse eutectic reaction) at approximately 1268 °C will occur with an endothermic reaction in some cases. The sharp endothermic peak between 1282 and 1303 °C is the reverse eutectic reaction, CaO·SiO2 + 2CaO·Al2 O3 ·SiO2 → Liquid. The blunt endothermic peak between 1388 and 1447 °C is the residual slag melting, Solid → Liquid. The relationships of C p with temperatures and compositions ( R, ratio of w (MgO)/ w (Al2 O3 ), and w (Al2 O3 )) are established with a good fit. Abstract : Herein, mineral transform and specific heat capacity ( C p ) characterization of blast furnace slag in heating process are investigated. There are phase transforms from amorphous to crystal and from solid to liquid in all cases. Reverse peritectic reaction or reverse eutectic reaction would proceed in some cases. The relationships of C p with temperatures and compositions are established with a good fit.