摘要
采用粒度≤74μm、w(MgCO3)=98.84%的工业纯菱镁矿,粒度<74μm、w(MgO)为40.0%～44.5%的分析纯碱式碳酸镁Mg(OH)2.4MgCO3.5H2O,以及粒度≤74μm、w(Al)≥99.9%的金属铝粉为原料,按照n(MgCO3)∶n(Al)=3∶4和n[Mg(OH)2.4MgCO3.5H2O]∶n(Al)=3∶28分别配料,采用机械合金化法,在室温条件下,以240 r.min-1的转速分别研磨15、30、50 h制得尖晶石-碳复合粉体。采用XRD分析、差热-热重分析和拉曼光谱等手段对复合粉体进行表征。结果表明:经过15～50 h的研磨后,两个反应体系中碳酸盐与金属铝粉之间发生原位分解和还原反应,都生成了尖晶石和碳;产物碳具有一定的石墨化程度,并与研磨时间密切相关;菱镁矿与金属铝粉之间生成尖晶石和碳的反应比碱式碳酸镁的快。
Commercial purity magnesite（ w（ MgCO3 ） ： 98.84% and particle size ≤74 μm）, analytically pure basic magnesium carbonate Mg （OH）2 · 4MgCO3 · 5H20（ （w（MgO） = 40.0%-44.5% and particle size 〈74 μm）and aluminum powder（w（AI） ≥99.9% and particle size ≤74 μm）were used as starting materials. The composite powders of MgAl2O4-C were prepared by batching according to n（ MgCO3 ）： n（Al） = 3：4 and nEMg（OH）2· 4MgCO3 · 5H2O]：n（AI） =3：28,respectively,and grinding for 15 h,30 h and 50 h at a planetary grinding mill with 240 r·min-1 of rotating speed by mechanical alloying method at room temperature. The resultant powders were characterized by X-ray diffraction （XRD）, differential scanning calormetry-thermogravimetry （DSC-TG） and Raman spectra. The results show that the in-situ decomposition and reduction reactions between carbonate and aluminum powder occur forming MgAI204 and C in these two reaction systems after 15-50 h grinding;the resultant carbon has a certain degree of graphitization which is strongly affected by the grinding time;the reaction between magnesite and aluminum forming spinel and carbon is earlier than basic magnesium carbonate and aluminum.
出处
《耐火材料》
CAS
北大核心
2012年第5期325-329,共5页
Refractories
基金
国家自然科学基金资助项目(510-72142)
关键词
机械合金化
制备
产物粉体
尖晶石
碳
mechanical alloying
preparation
resultant powder
spinel
carbon
