The effects of MgO and Al₂O₃ behaviours on softening–melting properties of high basicity sinter

Abstract

Because the behaviours of MgO and Al 2 O 3 during slag formation of high basicity sinter are not clearly understood, the effects of MgO and Al 2 O 3 on softening-melting properties are always arguable. In this paper, four kinds of sinter containing different MgO and Al 2 O 3 content are investigated. Some observations are obtained. The mechanism of the influence of MgO and Al 2 O 3 on softening properties of sinter are different. Al 2 O 3 has priority over MgO to enter into slag phase and forms low-melting point phase while MgO remains unslagged state and mainly exists in wustite as FeO-MgO solid solution. When sinter melts, the viscosity of the slag generated from sinter containing high MgO and Al 2 O 3 content is low, which could result in low pressure drop. As MgO and Al 2 O 3 content increase, the main minerals of residual slag change from 2CaO•SiO 2 to merwinte and melilite. The changes of the minerals in slag phase can well explain the trend of softening-melting characteristic temperatures.

Effect of Mineral Elements Migration on Softening–melting Properties of Ti–bearing High Basicity Sinter

“…The TiO 2 content is 6.61 mass%. The binary basicity R 2 (mass% CaO/ mass% SiO 2 ) and Al 2 O 3 content are 1.93 and 3.05 mass%, approximate to those of the ordinary high basicity sinter 15) (sample C in the literature) respectively.…”

“…The schematic diagrams of the apparatus and experimental conditions are given detailed in elsewhere. 15) The sample is heated at 10°C/min below 950°C, and kept at 950°C for 1 hour, and then heated at 5°C/min over 950°C. The gas flow is changed from N 2 (5 L/min) to reducing gas composed of CO and N 2 with the ratio 30/70 (12 L/min) until the sample temperature reaches 400°C.…”

“…It has been reported that softening-melting temperatures could be improved by increasing basicity. 11,12) The softening temperatures decreased [13][14][15] and dripping temperature increased 16) with increasing Al 2 O 3 content. Increasing MgO content could improve softening-melting properties of sinter.…”

Effect of MgO in Sinter and Primary‐Slag on Smelting Mechanism of Chromium‐Bearing Vanadium Titanomagnetite

“…The fraction of MgO–FeO solution increases with increasing MgO content. Hence, the melting point of MgO–FeO solution rises, and FeO is hard to dissolve into slag phase at softening stage of burden which leads to the rise of softening temperature …”

“…Hence, the melilite, gehlenite, and akermanite increase while merwinite decreases with increasing MgO content. The primary crystals of slag are perovskite and merwinite in the melting process, and merwinite has a high melting point . The MgO reacts with merwinite to generate other phases with high silicate ligand ion which represents the low polymerization degree and simple structure of primary‐slag due to the Mg 2+ as a network modifier with increasing MgO content.…”