高铁铝土矿直接还原回收粒铁和氧化铝

 采用煤基直接还原熔分技术和氧化铝溶出的方法，研究了直接还原工艺对粒铁尺寸和粒铁收得率的影响，以及钙铝比(w(CaO)/w(Al2O3))] 对渣相组成和渣中氧化铝的溶出影响。结果表明，当(w(CaO)/w(Al2O3))]为1.7、w(C)/w(O)]为1.4、还原熔分温度为1 450 ℃，还原熔分时间为20 min时，还原熔分过程中的粒铁尺寸最大，粒铁收得率也最高，粒铁尺寸和收得率分别为11.5 mm和93%。当(w(CaO)/w(Al2O3))]为1.0时，渣相组成主要以钙铝黄长石(Ca2Al(Al，Si)2O7)为主，当(w(CaO)/w(Al2O3))]为1.5时，渣相组成主要以钙铝黄长石(Ca2Al(Al，Si)2O7)、硅酸二钙(Ca2SiO4)和七铝十二钙(Ca12Al14O33)为主，当(w(CaO)/w(Al2O3))]为1.7～1.9时，渣相组成主要以七铝十二钙(Ca12Al14O33)和硅酸二钙(Ca2SiO4)为主。当(w(CaO)/w(Al2O3))]为1.7时，溶出时间为2.0 h时，氧化铝的溶出率最高，溶出率为87.5%，溶出率较0.5 h时提高了9.4%。因此，当渣系组成以七铝十二钙(Ca12Al14O33)和硅酸二钙(Ca2SiO4)为主时，更有利于氧化铝的溶出。

Direct reduction of high-iron bauxite for recovery of nuggets and Al2O3

Effects of the direct reduction process on the nuggets size and recovery percent were investigated by coal-based direct reduction and leaching process， and the effects of (w(CaO)/w(Al2O3))] on the slag composition and leaching rate of alumina were investigated by the same way. The results show that when the (w(CaO)/w(Al2O3))] is 1.7， w(C)/w(O)] is 1.4， reduction temperature is 1 450 ℃， and the reduction time is 20 min， the nuggets size is biggest and the nuggets recovery percent is highest， the nuggets size and recovery percent are 11.5 mm and 93%， respectively. When the (w(CaO)/w(Al2O3))] is 1.0， the furnace slag is mainly composed of gehlenite (Ca2Al(Al，Si)2O7)， when the (w(CaO)/]w(Al2O3))] is 1.5， the furnace slag is mainly composed of gehlenite (Ca2Al(Al，Si)2O7)， dicalcium silicate(Ca2SiO4) and mayenite(Ca12Al14O33)， when the w(CaO)/w(Al2O3)] is 1.7-1.9， the furnace slag is mainly composed of dicalcium silicate(Ca2SiO4) and mayenite(Ca12Al14O33). When the (w(CaO)/w(Al2O3))] is 1.7 and leaching time is 2.0 h， the leaching rate of alumina is highest which is 87.5%， the leaching rate is increased by 9.4% than that of 0.5 h leaching time. Therefore， when the furnace slag is mainly composed of dicalcium silicate(Ca2SiO4) and mayenite(Ca12Al14O33)， it is more conducive toleaching of alumina.