【作者】 李辉；

【导师】 金会心；

【作者基本信息】 贵州大学 ， 有色金属冶金， 2015， 硕士

【摘要】 我国优质铝土矿资源短缺问题日益明显,Al2O3生产成本居高不下,研究关于开发复杂难处理铝土矿的应用技术,将能够缓解我国对铝土矿的供求矛盾。本文以云南某难处理铝土矿为研究对象,对矿石的矿物特性、溶出性能、矿物反应行为进行了研究,以期获得利用该铝土矿的理论依据。铝土矿的矿物特性研究表明:矿石属于高铁高钛一水硬铝石型铝土矿,Al2O3含量为54.35%,A/S为8.02;矿石中含铁矿物以赤铁矿为主,伴有少量的绿泥石;含钛矿物以锐钛矿为主,同时有少量的Fe、Ti元素形成的钛铁矿。一水硬铝石在矿石中呈含砾砂屑状、碎屑状集合体产出,赤铁矿呈致密块状、层状、含砂泥质集合体产出,锐钛矿以细小状产出。铝土矿溶出性能研究表明:Al2O3溶出率偏低,是因为溶出过程形成的榍石会将一定量的Al2O3带入赤泥中,赤泥中的水合铝硅酸钠、水化石榴石、钙霞石也会引起Al2O3的损失。钛铁矿对矿石的溶出性能影响不显著。绿泥石中的Fe2+能够消除TiO2带来的危害,但矿石中绿泥石的含量较少,所以其对氧化铝溶出率的影响不显著,TiO2带来的危害主要由添加石灰来消除。在高温段(250~280℃),锐钛矿对Al2O3溶出有一定的阻碍作用,但随着溶出条件的加强这种阻碍作用相对减弱。试验获得的较佳溶出条件为,石灰添加量8%、溶出温度270℃、苛碱浓度225g/L、溶出时间60min;该条件下,Al2O3溶出率为77.74%,Fe2O3溶出率不足3%,TiO2溶出率仅在5%。动力学试验研究结果表明:选用区域反应动力学Hulbert-Klawitter方程2/3[?ln(1?x)]?klnt?C能够很好的描述Al2O3的溶出行为,反应表观活化能Ea=43.296kJ/mol,该过程受表面化学反应控制,但传质过程对反应速度仍具有不可忽略的影响。TiO2溶出行为选用动力学方程1/32t?K[1?(1?x)]?C能够很好的描述,反应表观活化能Ea=77.320kJ/mol,该过程受化学反应控制。更多还原

【Abstract】 The shortage of high quality bauxite resources in C hina is becoming increasingly obvious, and the production costs of Al2O3 remain high. Therefore, the conflict of supply and demand in bauxite could be solved by studying the application of dealing with complex refractory bauxite. Refractory bauxite from Yunnan was studied, the mineral characteristics, dissolution properties and mineral reaction behavior were studied to obtain theoretical basis of the bauxite in this paper.The results of mineralogical characteristics show that the ore was of diasporic bauxite with high ferrous and high titaniferous, the content of Al2O3 was 54.35%, and A/S was 8.02; ferrous mineral in ore was mainly hematite with a small amount of chlorite; titanium mineral was mainly anatase, which also contain ilmenite formed by a small amount of Fe and Ti. Diasporic bauxite in the ore output through aggregation of gravel sand and clastic, hematite output through aggregation of compact mass, lamellar and mud with sand, anatase mainly output through small shape.The dissolution performance of bauxite shows that titanite drgged some certain amount of Al2O3 into red mud, which lead to low dissolution ra te of alumina, sodium alumino silicate hydrate, hydrate garnet and cancrinite also lead to the loss of Al2O3. Fe2+ in chlorite could eliminate the harm caused by TiO2, but chlorite ore content was low, which did not significantly affect the dissolution rate of alumina, the addition of lime could eliminate the influence of TiO2. In the high temperature section(250~280℃), the anatase has some effect on the dissolution of alumina, but the effect of the dissolution is relatively weakened with the strengthening of the dissolution conditions. Better dissolution conditions were obtained: amount of lime addition was 8%, solution temperature was 270℃, caustic concentration was 225g/L, dissolution time was 60min; under these conditions, dissolutio n rate of Al2O3 was 77.74%, dissolution rate of Fe2O3 was less than 3%, dissolutio n rate of TiO2 was only 5%.Kinetic experiments results show that the digestion behavior of Al2O3 could be described by regional reaction kinetics equation of Hulbert-Klawitter, that the kinetics is [?ln(1?x)]2/3 ?kln t ?C, apparent activation energy of reaction was Ea=43.296kJ/mol, the process was controlled by surface chemical reaction, but mass transfer process still affected the reaction rate, which can not be ignored. The dissolution behavior of TiO2 was well described by kinetic equation, that the kinetics is 1/32 t ?K[1?(1?x) ] ?C and the apparent activation energy was Ea=77.320 k J/mol, which was controlled by chemical reaction.更多还原