化工进展
化工進展
화공진전
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS
2014年
12期
3215-3220
,共6页
葛琦%王恒%满毅%李富杰%庞立伟
葛琦%王恆%滿毅%李富傑%龐立偉
갈기%왕항%만의%리부걸%방립위
赤泥%热分析%直接还原%粒度分布%反应动力学%扩散
赤泥%熱分析%直接還原%粒度分佈%反應動力學%擴散
적니%열분석%직접환원%립도분포%반응동역학%확산
red mud%thermal analysis method%direct reduction%size distribution%reaction kinetics%diffusion
为了得出粒度对赤泥在煤基条件下等速率加热过程中的直接还原反应的转化过程及反应动力学的影响,采用热分析技术、扫描电镜等手段研究了赤泥在直接还原过程中的热行为和不同条件下焙烧产物中铁矿物的存在形式等。实验结果发现,煤基条件下的直接还原反应主要分为赤泥脱水和铁氧化物还原两个阶段。通过计算得出了这几种粒度的赤泥的还原度,同时运用Coats-Redfern积分法推断出了试样在各个阶段的最概然机理函数和活化能、频率因子等反应动力学参数,并且用Flynn-Wall-Ozawa法对计算结果进行了验证。
為瞭得齣粒度對赤泥在煤基條件下等速率加熱過程中的直接還原反應的轉化過程及反應動力學的影響,採用熱分析技術、掃描電鏡等手段研究瞭赤泥在直接還原過程中的熱行為和不同條件下焙燒產物中鐵礦物的存在形式等。實驗結果髮現,煤基條件下的直接還原反應主要分為赤泥脫水和鐵氧化物還原兩箇階段。通過計算得齣瞭這幾種粒度的赤泥的還原度,同時運用Coats-Redfern積分法推斷齣瞭試樣在各箇階段的最概然機理函數和活化能、頻率因子等反應動力學參數,併且用Flynn-Wall-Ozawa法對計算結果進行瞭驗證。
위료득출립도대적니재매기조건하등속솔가열과정중적직접환원반응적전화과정급반응동역학적영향,채용열분석기술、소묘전경등수단연구료적니재직접환원과정중적열행위화불동조건하배소산물중철광물적존재형식등。실험결과발현,매기조건하적직접환원반응주요분위적니탈수화철양화물환원량개계단。통과계산득출료저궤충립도적적니적환원도,동시운용Coats-Redfern적분법추단출료시양재각개계단적최개연궤리함수화활화능、빈솔인자등반응동역학삼수,병차용Flynn-Wall-Ozawa법대계산결과진행료험증。
In order to study the effects of particle size on the transformation process and path of red mud under coal-based direct reduction condition during heating process at constant rate,the thermal behavior of red mud under direct reduction conditions was studied with thermal analysis and the existence form of iron minerals in roasted products under different roasting conditions was observed with scanning electron microscopy(SEM). Direct reduction process under coal-based condition could be mainly divided into two stages:dehydration and Fe oxides reduction. Furthermore,the reduction degrees of red mud at four particle sizes were obtained. The chemical kinetic parameters at different stages,such as appropriate kinetic mechanisms functions,activation energy and frequency factor were calculated by using the Coats-Redfern method and verified by using the Flynn-Wall-Ozawa method.