轻烧温度及球磨工艺对盐湖Mg(OH)_(2)制备镁砂烧结行为影响  

Effects of Calcination Temperature and Ball Milling on Sintering Behavior of Magnesia from Salt Lake Mg(OH)_(2)

作　　者：徐义彪[1] 李亚伟[1] 鄢文[1] 周芬 XU Yibiao;LI Yawei;YAN Wen;ZHOU Fen(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;Wugang Refractory Co.Ltd.,Wuhan 430082,China)

机构地区：[1]武汉科技大学,省部共建耐火材料与冶金国家重点实验室,武汉430081 [2]武汉钢铁集团耐火材料有限责任公司,武汉430082

出　　处：《硅酸盐学报》2024年第9期3003-3011,共9页Journal of The Chinese Ceramic Society

基　　金：青海省科技成果转化专项项目(2023-GX-10);国家自然科学基金联合基金重点项目(U21A2058)。

摘　　要：以盐湖氢氧化镁为原料,经650、750、850℃和950℃保温1 h轻烧,随后将轻烧MgO团聚体球磨(0.5、1.0、3.0、5.0、12.0、24.0 h)破碎,压制成型后于1600℃保温3 h制备了烧结镁砂,探讨了轻烧温度及球磨时间对镁砂显微结构及烧结性能的影响。结果表明:随轻烧温度由650℃升高到850℃,轻烧MgO团聚体内微晶平均尺寸由138 nm增加至180 nm,尽管微晶活性降低,但残余氢氧化镁减少,镁砂致密性呈增大趋势。轻烧温度升高至950℃,MgO微晶平均尺寸迅速增加至320 nm,活性大幅降低,镁砂晶粒尺寸及致密性显著降低。球磨工艺可以有效破坏轻烧MgO团聚体,其平均尺寸球磨0.5 h后由55.90μm迅速降至2.69μm,并随研磨时间增加至12 h逐渐降至1.72μm,但进一步增加球磨时间团聚体尺寸基本不变。MgO团聚体的破坏减少了生坯中大气孔,提高了晶粒接触程度及传质速率,促进了晶粒长大及样品致密化。850℃制备的轻烧MgO球磨12 h压制的生坯,经1600℃保温3 h烧结,可制备平均晶粒30.4μm,体积密度达3.42 g/cm3的致密镁砂。Introduction Magnesia,acted as a refractory material,is widely used in industrial metallurgical furnaces owing to its high refractoriness and excellent corrosion resistance to basic slag and metal melt.Generally,the fabrication of high-quality magnesia aggregates with high purity and high bulk densities(>3.40 g/cm^(3))plays a critical role in producing MgO-based refractories that show satisfying mechanical properties and corrosion resistance.In China,magnesite is mainly used as a raw material to produce sintered magnesia at high-temperature.while,as the generally coarse-grained of magnesite,it is difficult to produce high density magnesia even sintered at high temperatures,being due to the poor sintering property.As reported that the introduction of oxides additives such as TiO_(2),Al_(2)O_(3)ZrO_(2),etc.could effectively promote the sintering of magnesia.However,the additives also resulted in a low melting phase formation,which significantly reduced the high-temperature performance of magnesia.In fact,besides magnesite,China also has abundant magnesium resources in salt lakes.Compared to magnesite,magnesia derived from salt lake owns the advantage of higher purity and without CO_(2)emissions during the production process.In this work,magnesium hydroxide produced from salt lake was used as raw material to prepare the high-purity dense magnesia via a two-step method.Effects of calcination temperature and grinding time on the morphology and sintering activity of MgO were studied,microstructure and densification behavior of magnesia sintering at high-temperature were investigated also.Methods Magnesium hydroxide powder[Mg(OH)_(2)]was used as raw material.Firstly,it was lightly-burned to produce MgO when calcined at 650,750,850℃and 950℃with a holding time of 1 h and a heating rate of 5℃/min,repetitively.Secondly,the obtained powder was finely ground using mechanical ball milling for 0.5,1.0,3.0,5.0,12.0℃and 24.0 h,respectively,here,zirconia balls acted as the media and anhydrous ethanol as solvent.Thirdly,the

关 键 词：盐湖氢氧化镁 烧结镁砂 轻烧温度 晶粒尺寸 致密化 

分 类 号：TQ175[化学工程—硅酸盐工业]