镍基高温合金废料的回收工艺研究

【作者】 李彬；

【导师】 段云彪； 王玉天；

【作者基本信息】 昆明理工大学 ， 材料工程（专业学位）， 2020， 硕士

【摘要】 本论文以火法—湿法联合工艺对镍基高温合金废料进行回收,提出“与镓合金化处理-溶解-化学除杂-镍钴分离及镓分离回收”的工艺流程,首次采用低熔点金属—镓作为合金元素与镍基高温合金废料进行合金化,以期通过与镓合金化处理有效降低镍基高温合金废料溶解浸出难度,并提高合金废料的溶解浸出效率,分别研究了镍基高温合金废料与镓的合金化工艺;镍基高温合金废料和新合金的溶解浸出效率;浸出液化学除杂以及镍钴萃取分离;除杂沉淀中镓的分离。以镓作为合金化元素,对镍基高温合金废料进行合金化处理的方法是可行的,通过合金化处理可以完全改变镍基高温合金废料的组织结构,得到两组优化后的合金化工艺参数:（1）在氩气气氛中,处理温度为1000℃、镓与镍基高温合金废料的质量比为1.0及保温时间为6 h的条件下处理得到Ⅰ号新合金;（2）在氩气气氛中,处理温度为900℃、镓与镍基高温合金废料的质量比为1.8及保温时间为8 h的条件下处理得到Ⅱ号新合金。在盐酸体系、硫酸体系中相同条件下,Ⅰ号新合金的溶解效果稍强于原镍基高温合金废料;在王水中Ⅰ号新合金的浸出效率明显高于原镍基高温合金废料,在温度为25℃、液固比（ml:g）为12、反应时间为6 h的条件下,Ⅰ号新合金中镍、钴和镓的浸出率分别能达到97.69%、97.38%和99.12%;在硫酸浓度为6 mol/L、氯酸钠与新合金的质量比为2、温度为75℃、液固比（ml:g）为30、反应时间8 h的条件下,Ⅱ号新合金的溶解浸出效率远高于原镍基高温合金废料,镍、钴、镓的浸出率分别为98.67%、98.48%和99.87%;以上证明通过与镓合金化处理,可以有效降低镍基高温合金废料溶解浸出难度,并提高废料的溶解浸出效率。通过1 mol/L Na₂CO₃溶液调节浸出溶液的p H=5.07,可以有效除去溶液中镓、铬等离子,镍、钴的沉降率仅为0.46%和0%,同时,溶液中99.97%的镓元素富集于除杂沉淀中,有利于后续对镓的分离回收。采用溶剂萃取法对模拟溶液进行镍钴分离实验,得到优化的镍钴萃取分离工艺参数:待萃液初始p H值为3.0、萃取剂P507的体积浓度为10%、P507皂化率为55%、相比O/A为1:2、震荡时间为5 min;在优化的萃取条件下,进行镍钴萃取分离,镍的单级萃取率为0.78%,钴的单级萃取率为68.08%,镍钴萃取分离系数β_{C o/Ni}为271.41,镍钴萃取分离效果较好;负载有机相中的镍可以通过0.01mol/L稀盐酸溶液（p H值为2.0左右）进行洗涤除去,单级洗涤中镍的反萃率为63.8%,钴的反萃率仅为0.48%,单级洗涤除镍的效果较好。对除杂沉淀中的镓元素进行分离实验,本论文以1 mol/L HCl溶液溶解含镓滤渣,然后通过1 mol/L Na OH溶液调节溶液p H为11～12可分离除去杂质铬、铁等元素。得到优化的镓萃取分离工艺参数:在相比O/A为2:1、萃取时间为15 min的条件下,待萃液酸度为6 mol/L、TBP体积分数为20%时,镓的萃取率可达到99%以上。更多还原

【Abstract】 In this master’s thesis,scrap nickel base superalloy is recovered by the combined process of smelting and hydrometallurgy.The technological process of"alloying with gallium-dissolution-chemical impurity removal-separation of cobalt and nickel-separation and extraction of gallium"is proposed in this thesis.Low melting point metal gallium was used as alloying element for the first time to alloying the scrap nickel base superalloy,so as to effectively reduce the difficulty of dissolving and leaching of the scrap nickel base superalloy and improve the dissolution and leaching efficiency of scrap alloy by alloying with gallium.In this thesis,alloying process of the scrap nickel base superalloy and gallium,dissolution leaching efficiency of the scrap nickel base superalloy and new alloy,leaching liquefaction and nickel cobalt extraction separation,gallium separation in impurity removal precipitation were studied respectively.It is feasible to use gallium as an alloying element to alloying the scrap nickel base superalloy.The microstructure of the scrap nickel base superalloy can be completely changed by alloying.Two groups of optimized alloying process parameters were obtained:（1）In argon atmosphere,the processing temperature is 1000℃,the mass ratio of gallium to the scrap nickel base superalloy is 1.0 and the holding time is 6 h,under the condition of alloying processingⅠnew alloy can be obtained.（2）In argon atmosphere,the processing temperature is 900℃,the mass ratio of gallium to the scrap nickel base superalloy is 1.8 and the holding time is 8 h,under the condition of alloying processingⅡnew alloy can be obtained..When the temperature was 25℃,the ratio of volume to mass was 12 and the reaction time was 6 h,the leaching rates of nickel,cobalt and gallium in theⅠnew alloy were 97.69%,97.38%and 99.12%,respectively.When sulfuric acid concentration is 6 mol/L,the mass ratio of sodium chlorate to the new alloy is 2,the temperature is 75℃,the liquid-solid ratio（m L:g）is30,and the reaction time is 8 h,the dissolution leaching efficiency of theⅡnew alloy is much higher than that of the original nickel-based superalloy.The leaching rates of nickel,cobalt and gallium are 98.67%,98.48%and 99.87%respectively.The above results show that gallium alloying treatment can effectively reduce the difficulty of dissolution and leaching of the scrap nickel base superalloy and improve the efficiency of dissolution and leaching of the scrap nickel base superalloy.By adjusting the p H of leaching solution with 1 mol/L Na₂CO₃ solution to 5.07,gallium and chromium plasma in the solution can be effectively removed,and the deposition rates of nickel and cobalt are only 0.46%and 0%.Meanwhile,99.97%of gallium in the solution is enriched in the impurity removal precipitation,which is conducive to the subsequent separation and recovery of gallium.The solvent extraction method was used for the nickel and cobalt separation experiment of the simulated solution,and the optimized technological parameters of the nickel and cobalt extraction separation were obtained:the initial p H value of the extract was 3.0,the volume concentration of the extractant P507 was 10%,the saponification rate of P507 was 55%,the ratio of O/A was 1:2,and the oscillation time was 5 min.The single stage extraction rate of nickel was 0.78%,the single stage extraction rate of cobalt was 68.08%,and the extraction and separation coefficient of nickel and cobalt was 271.41.Nickel in the loaded organic phase can be removed by washing with 0.01 mol/L dilute hydrochloric acid solution（p H value around 2.0）.The back extraction rate of nickel in single-stage washing is 63.8%,while that of cobalt is only0.48%In this case,the nickel removal effect of single stage washing is better.The gallium element in impurity removal precipitation was separated by experiments.In this paper,gallium containing filter residue was dissolved in 1 mol/L HCl solution,and then the p H value of the solution was adjusted to 11～12 by 1 mol/L Na OH solution,which could separate and remove impurities such as chromium and iron.Optimized gallium extraction and separation process parameters were obtained:when compared with O/A at 2:1 and extraction time at 15 min,the extraction rate of gallium could reach more than 99%when the hydrogen ion concentration of the extract was 6 mol/L and the volume fraction of TBP was 20%.更多还原