【作者】 王明；

【导师】 戴曦；

【作者基本信息】 中南大学 ， 冶金工程， 2012， 硕士

【摘要】 含铂废催化剂资源丰富,品位远高于含铂矿床,具有极高的回收价值。催化剂在高温使用过程中,部分载体会由γ-Al2O3转变为α-Al2O3,并包裹少量铂,致使直接浸出活性组分时,铂浸出率不高,而全溶解法存在试剂消耗大,环境污染严重等缺点。基于上述全溶解法和活性组分溶解法之不足,本研究着眼二次资源综合利用,立足工厂现有生产实际,结合原料成分复杂之特性,采用热酸球磨工艺、高压碱浸工艺以及烧结-溶出工艺溶解废催化剂载体,实现铂的有效富集及载体铝的综合回收。本文首先通过多种分析检测手段研究了原料性质,阐明了工艺过程原理,在此基础上,考察了不同工艺参数对载体溶出过程的影响,并将机械活化引入酸浸过程,探讨了机械活化对浸出过程的强化作用。获得主要研究成果如下：原料为成分复杂的废重整催化剂,Al主要以γ-Al2O3形式存在(部分α-Al2O3),另外还有少量Al、Si赋存在Na2O-Al2O3-SiO2-H2O中,C和SiO2含量比较高,分别为6.16%和4.54%,且成分偏析严重。高压碱浸优化工艺条件为：原料于600℃焙烧1h,浸出液苛碱浓度230g/L,浸出温度260℃,苛性比1.6,浸出时间2h。一次浸出,渣率为10.52%,Al2O3浸出率95.93%,SiO2浸出率59.71%,渣中铂含量由浸出前的0.23%提高到浸出后的2.08%,较浸出前富集了9.04倍。烧结-溶出优化工艺条件为：原料于600℃焙烧1h,烧结温度800℃,配料分子比1.2,烧结时间2h,烧结产物于95℃热水溶出10min。一次烧结-溶出,渣率为5.04%,Al2O3溶出率98.10%,SiO2溶出率85.23%,Na2O溶出率99.25%,渣中铂含量由浸出前的0.23%提高到浸出后的4.11%,较浸出前富集了17.87倍。热酸球磨优化工艺条件为：原料于550℃焙烧2h,球料比13：1,磨球级配Φ10：φ6：φ4=3：4：4,球磨机转速6r/min,浸出温度100℃,浸出时间2h,硫酸浓度50%,液固比5：1。一次浸出,渣率为10.56%,Al2O3浸出率95.70%,SiO2浸出率9.56%,渣中铂含量由浸出前的0.25%提高到浸出后的1.80%,较浸出前富集了7.20倍。动力学研究表明,热酸球磨浸出较常规搅拌浸出,Al2O3浸出过程表观活化能降低了10.99kJ/mol。浸出液中铝采用蒸发-结晶法以硫酸铝形式回收,产品含量和外观均满足HG/T2225-2001Ⅰ型一等品硫酸铝要求。碱溶(熔)工艺虽然可以降低渣率,但不利于与企业现有工艺衔接及浸出液中铝的综合回收,而且渣中钠硅渣的存在会影响后续铂回收,综合考虑上述因素,热酸球磨工艺更优。更多还原

【Abstract】 Spent platinum catalysts posses extremely high recovery value due to its abundant resources and high grade as compared with platinum ore. Some Substrate of spent platinum catalysts can convert from γ-Al2O3to α-Al2O3under high temperature, which has resulted in the low leaching rate of platinum by active components dissolution because of the encapsulation of few platinum. The disadvantages of whole dissolution method include high consumption of regents and environmental pollution.In the present study, production processes including thermal acid ball-milling, alkali leaching with high pressure and sintering-leaching were adopted based on the disadvantages of whole dissolution method and active components dissolution method, as well as the comprehensive consideration of factors, such as utilization of secondary resources, production practice of factory and complex components of raw materials.Firstly, properties of raw material were analyzed using various analysis detection methods in order to elucidate the principle of the production process. Effect of various production parameters on the leaching process was studied. Also mechanical activation was used in the acid leaching process and its strengthening effect on the leaching process was discussed. The results showed:Aluminum in the spent reforming catalysts was appeared mainly in the form of γ-Al2O3with partially α-Al2O3. Few Al and Si were hosted in Na2O-Al2O3-SiO2-H2O system. The contents of C and SiO2were relatively high, which were6.16%and4.54%, respectively. Composition segregation of the raw materials was serious.Optimum process conditions for alkali leaching under high pressure were listed as follows:roasting at600℃for1h, concentration of NaOH in leaching solution was230g/L, leaching temperature260℃, caustic ratio1.6, leaching time2h. Slag ratio and leaching percentages of Al2O3and SiO2in the first leaching process was10.52%,95.93%and59.71%, respectively. Platinum content in slag was significantly increased from0.23%to2.08%after the leaching process, with the enrichment factor increased9.04times as compared to the raw materials.Optimum process conditions for sintering-leaching process were listed as follows:roasting at600℃for1h, sintering temperature800℃, molecule ratio1.2, sintering time2h, sintering products were digested at95℃for10min. Slag ratio and leaching percentages of Al2O3, SiO2and Na2O in the first leaching process was5.04%,98.10%,85.23%and99.25%, respectively. Platinum content in slag was significantly increased from0.23%to4.11%after the leaching process, with the enrichment factor increased17.87times as compared to the raw materials.Optimum process conditions for sintering-leaching process were listed as follows:roasting at550℃for2h, ball-to-powder weight ratio13:1, ball gradation Φ10:Φ6:Φ4=3:4:4, ball-mill speed6r/min, leaching temperature100℃, leaching time2h, H2SO4concentration50%, liquid-solid ratio5:1. Slag ratio and leaching percentages of Al2O3and SiO2in the first leaching process was10.56%,95.70%,9.56%, respectively. Platinum content in slag was significantly increased from0.25%to1.80%after the leaching process, with the enrichment factor increased7.20times as compared to the raw materials. Kinetics of thermal acid ball-milling showed apparent activation energy of Al2O3in the leaching process decreased by10.99kJ/mol compared to conventional stirring leaching process. Aluminum in the leaching solution of thermal acid ball-milling process was recovered by evaporation ammonia method. The product in the form of aluminum sulfate could meet the standard of the first grade in HG/T2225-2001Ⅰ.Though alkali dissolution (fusion) process could effectively reduce slag ratio, it still show some disadvantages, such as contradictory with existing process, and aluminum (Al) in the leaching solution can not be effectively recycled. Also sodium-silicon residue in slag exerted negative effect for subsequent recovery of platinum. Based on comprehensive consideration of the above factors, thermal acid ball-milling process was selected as optimum production for platinum recovery.更多还原