Study on the Physicochemical Properties of Burnt Dolomite for the Steelmaking

炼钢用烧成白云石物化性能研究

• 批准号: 62550493
• 负责人: MITSUO Toshiharu
• 金额: $ 1.15万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62550493/
• 关键词: Dolomite; Burnt dolomite; Fluxing of burnt dolomite; Hydration of burnt dolomite; Dolomite for refining; Dolomite for steelmaking; Refining of LD converter; Flux for refining; 鉄鋼用ドロマイト; 転炉製錬

Several properties of dolomites, produced from six areas in Japan, were investigated. Additional experiments were carried out to study the relationship between hydration reactivity of burnt dolomites and fluxing property to molten slag.1. Reaction process of burnt dolomite: The reaction process of burnt dolomites can be divided into two stages in both hydration and fluxing. One is breaking stage in which the burnt dolomite breaks into small particles to be suspended in agitated water or slag due to macro crack. Another is dissolution stage in which CaO and MgO are dissolved from the surface of each particle due to chemical reactions. The reactivity of burnt dolomites is determined by macroscopic surface area and microscopic surface area. That is the area of surface of each particle produced in braking stage and this is due to clearance among micro grains formed in calcination.2. Hydration reactivity: In lower calcination temperature, hydration reactivity of burnt dolomite is affected by the grain size at raw state. Large grain promotes the formation of so many macro cracks even at lower temperature as to kept the hydration reactivity high. On the other hand, hydration reactivity of burnt dolomite with small grain size becomes higher according to formation of more macro cracks at higher calcination temperature. At much higher calcination temperature, however, decrease of microscopic surface area due to recrystallization leads the reduction of hydration reactivity regardless of the grain size.3. Fluxing property: Fluxing property becomes smaller with increase of calcination temperature. But, this reduction in fluxing property is not so remarkable as that in hydration reactivity. The reason is that the erosion ability of employed acid slag, including a plenty of FeO, to burnt dolomite is large, so fluxing property does not fall down so much at high calcination temperature.

本文研究了日本六个地区生产的膨润土的若干性质。另外，还研究了烧石膏的水化反应性与熔渣助熔性之间的关系.煅烧白云石的反应过程：煅烧白云石的反应过程可分为水化和助熔两个阶段。一是破碎阶段，烧成的白云石由于宏观裂纹而破碎成小颗粒，悬浮在搅拌的水中或炉渣中。另一个阶段是溶解阶段，其中CaO和MgO由于化学反应而从每个颗粒的表面溶解。煅烧高岭土的反应活性由宏观表面积和微观表面积决定。这是在制动阶段产生的每个颗粒的表面积，这是由于在煅烧过程中形成的微颗粒之间的间隙.水化反应性：在较低的煅烧温度下，煅烧白云石的水化反应性受原料粒度的影响。大晶粒在较低温度下也能促进大量宏观裂纹的形成，从而保持较高的水化反应活性。另一方面，煅烧温度越高，小粒径煅烧白云石的水化反应活性越高，形成的宏观裂纹越多。但在较高的煅烧温度下，由于再结晶导致的微观比表面积的减小导致水化反应活性的降低，而与晶粒尺寸无关.助熔性：助熔性随煅烧温度的升高而降低。但是，这种熔融性的降低并不像水化反应性那样显著。其原因是所用的酸性渣中含有大量的FeO，对烧成白云石的侵蚀能力大，在高温煅烧时助熔性能下降不大。