【作者】 卢毅屏；

【导师】 王淀佐；

【作者基本信息】 中南大学 ， 矿物加工工程， 2012， 博士

【摘要】 论文以高效利用我国中低铝硅比的一水硬铝石型铝土矿为目标,开展铝土矿选矿脱硅研究。根据这类资源特点,认为铝土矿选矿必须实现全粒级回收A1203,其技术关键环节是微细粒级铝、硅矿物的分离和粗粒连生体的回收。论文以复合捕收剂疏水聚团为基础,系统地进行了铝土矿选择性磨矿-聚团浮选工艺与机理的研究。研究表明,对于铝硅比在3-6范围的铝土矿矿石,磨矿产品的粒度分布呈两极分化,磨矿产品普遍具有选择性碎解特征,+0.074mm粒级的铝硅比较原矿铝硅比高1-2,但以矿物连生体为主,可浮性差；捕收剂油酸钠在一水硬铝石表面的吸附量远高于在铝硅酸盐脉石矿物表面,铝、硅矿物具有较好的选择性分离基础。由此认为,铝土矿选择性磨矿-聚团浮选的工艺基础对于中低铝硅比铝土矿具有普适性。油酸钠作为捕收剂浮选时,一水硬铝石颗粒间同相聚集,其本质为疏水絮凝。一水硬铝石的可浮性与聚团的表观粒度呈正相关关系。六偏磷酸钠抑制一水硬铝石的浮选,使聚团粒度降低；增加油酸钠用量、提高浮选温度以及油酸钠和羟肟酸、表面活性剂OL组成的复合捕收剂均可增加聚团粒度,提高一水硬铝石的可浮性。油酸钠在一水硬铝石表面的吸附形式随温度而变化,并影响浮选。在低温(15℃)下,油酸钠在一水硬铝石表面的吸附等温线呈典型的由三个直线段构成的S型,达到半胶束吸附时的油酸钠浓度远高于浮选浓度,因此,低温下油酸钠的捕收能力弱。升高温度到32℃,油酸钠的吸附等温线向L型转变,低油酸钠浓度下的吸附量增大,并对应着一水硬铝石聚团粒度增大和可浮性提高。研究发现,一水硬铝石的浮选和疏水聚团均易发生在捕收剂溶液表面张力的低值区。少量羟肟酸和表面活性剂OL可以降低油酸钠溶液的界面张力,并与提高捕收能力和促进疏水聚团有对应关系。其中苯甲羟肟酸提高了油酸钠在一水硬铝石表面的吸附量。提出可以将药剂的表面张力值作为初步筛选以油酸钠为主的复合捕收剂的一个判据,并据此形成了一种以油酸钠、苯甲羟肟酸和OL系列药剂组成的铝土矿脱硅复合捕收剂。选择性磨矿-聚团浮选工艺研究结果表明,捕收剂组合、搅拌强度等因素影响铝土矿聚团浮选效果。基于复合捕收剂KL的选择性磨矿-聚团浮选工艺,对于中、低铝硅比矿石均有良好的适应性,在对不同产地、不同铝硅比的各种规模的铝土矿选矿脱硅中,均获得了良好的技术指标。对山西铝土矿的扩大连续试验,在原矿铝硅比为4.32时,可获得精矿铝硅比为11.23、Al2O3回收率85.28%的选别指标。对中州铝土矿的工业试验结果表明,铝硅比为6左右中等铝硅比矿石,可获得精矿铝硅比12.33、Al2O3回收率88.74%的指标；对于铝硅比为4左右的低铝硅比矿石,也可获得精矿铝硅比9.34、A1203回收率79.15%的指标。选择性磨矿-聚团浮选工艺在中国铝业中州分公司的生产应用中,对铝硅比为5.5左右和3.5左右的铝土矿选矿脱硅,均取得了良好的效果,为拜尔法生产氧化铝提供了可靠的优质原料,为解决优质铝土矿资源短缺问题,提供了一个有效的途径。更多还原

【Abstract】 Aiming at efficient utilization of diaspore type bauxite with medium and low alumina-silica ratio, the bauxite desiliciation by beneficiation was studied. It is concluded that Al2O3of all sizes must be recovered in bauxite beneficiation, in which the key technology is the comprehensive recovery of both micro size resource and coarse intergrowth. Based on hydrophobic aggregation of combined colletors, a new processing technology of bauxite-selective grinding-aggregation flotation was investigated, and its mechanism was discussed.It was shown that the bauxite grinding products with alumina-silica ratio3-6exhibited a great difference not only in size distribution, but also in disintegration. Usually, bauxite with+0.074mm size after grinding is1-2higher in alumina-silica ratio than that of the raw ores, but the mineral particles in thus size is mainly intergrowth and its flotability was very poor. The adsorption of sodium oleate on diaspore surface was considerably higher than that on aluminosilicate surface and it exhibited a selective collection of diaspore. In this way, bauxite selective grinding-aggregation process was commonly suitable for bauxite with medium and low alumina-silica ratio.The same-phase aggregation between diaspore particles could be observed due to hydrophobic aggregation when sodium oleate was used as collector. The flotability of diaspore was positively correlated with the apparent size of hydrophobic aggregate. That is to say, the factors affecting aggregate apparent size could also affect the mineral flotability: sodium hexametaphosphate depresses diaspore flotation because it decreased the aggregate size; Both the aggregate size and flotability of diaspore were greatly promoted when increasing sodium oleate dosage, increasing flotation temperature and using combined collector consisting of sodium oleate, hydroximic acid and OLThe adsorption of sodium oleate on diaspore surface changed as a function of temperature which affected the flotation of diaspore. It could be observed that adsorption isotherm of sodium oleate on diaspore surface presents a typical S type consisting of three line segments under low temperature (15℃). The concentration of semi-micelle adsorption of sodium oleate was much higher than that of flotation. When the temperature was increased to32℃, the adsorption isotherm of sodium oleate turned to L type. The adsorption of sodium oleate in low concentration increased, resulting in the increases of aggregate size and flotability of diaspore correspondingly.The diaspore flotation and hydrophobic aggregation tended to appear in the area where surface tension of collector solution was low. A little hydroximic acid and surfactant OL could decrease the surface tension of sodium oleate solution and correlate with improvement the hydrophobic aggregation and flotation of diaspore, in which benzohydroxamic acid could increase the adsorption of sodium oleate on diaspore. So the combined collectors with sodium oleate dominating could be preliminarily selected out by using reagent surface tension as a criterion. A new combined collector with sodium oleate, benzohydroxamic acid and OL was developed and applied in bauxite desilication.The aggregation flotation performance of bauxite could be affected by such factors as collector combination and stirring intensity. Selective grinding-aggregation flotation process with combined collector KL was pretty suitable for bauxite desilication by beneficiation and satisfying technology index of bauxite with different alumina-silica ratio could be obtained. Bench-scale tests on bauxite from Shanxi was carried out and beneficiation index of concentrator alumina-silica ratio11.23and Al2O3recovery85.28%were obtained from a raw ore with alumina-silica ratio4.32. Industrial tests on bauxite from Zhongzhou showed that beneficiation index of concentrator alumina-silica ratio12.33and recovery88.74%could be obtained from a bauxite ore with alumina-silica ratio6. And for bauxite with alumina-silica ratio as low as4, index of concentrator alumina-silica ratio9.34and recovery79.15%could also be obtained. Selective grinding-aggregation flotation process has been applied in Zhongzhou Branch, Aluminum Corporation of China and has obtained good desilication performance for bauxite with alumina-silica ratio5.5and3.5. This process provided reliable quality raw materials for aluminium oxide production by Bayer’s method has been served as an effective way for alleviating high quality bauxite shortage.更多还原