广西太平矿区外围铝土矿石灰-拜耳法溶出试验

广西平果县太平矿区外围铝土矿石属高铝高铁含钛一水硬铝石型铝土矿石。为了确定该矿石中Al_2O_3的溶出工艺条件,对矿石的磨矿细度、溶出温度、铝酸钠母液苛性碱浓度、石灰用量以及溶出时间进行了研究。结果表明,在矿石磨矿细度为-63μm占83%,溶出温度为260℃,铝酸钠母液苛性碱浓度为240 g/L,石灰用量为6%,溶出时间为50 min情况下,Al_2O_3相对溶出率达97.32%。

广西某铝土矿Bayer-CaO法溶出试验

对广西太平矿区外围铝土矿进行了矿物工艺学分析,研究了铝土矿中各元素的赋存状态,分析了母液苛性碱浓度Nk、石灰添加量、溶出温度、溶出时间对Al2O3溶出率的影响,并对该工艺条件下获得的赤泥进行了沉降分析,结果表明:溶出时间50min、溶出温度260℃、母液Na2Ok240.00g/L、αk3.4、石灰添加量6%-63μm为较佳工艺条件下,Al2O3相对溶出率达到97.71%。

Reaction kinetics and mechanism of calcium oxide in dilute sodium aluminate solution with oxalate based on lime causticization

The formation kinetics and mechanism of tricalcium aluminate hydrate and calcium oxalate in dilute sodium aluminate solution and sodium oxalate solution were studied respectively based on the lime causticization, and the optimal conditions for removing the oxalate in dilute sodium aluminate solution as well as the mechanism were finally obtained.The formation processes of tricalcium aluminate hydrate and calcium oxalate are mainly controlled by the chemical reaction and the inner diffusion respectively,and the corresponding reaction rate equations as well as the apparent activation energy were calculated. The hydrocalumite with a spatially interleaved structure will form in dilute sodium aluminate solution with sodium oxalate, greatly removing the oxalate impurity by absorption. Calcium oxalate can be converted to tricalcium aluminate hydrate with the increasing reaction time. The oxalate causticization efficiency and the alumina loss rate can be over 90% and below 31% respectively when reacted at 50℃ with a stirring rate of 200 r/min.