【作者】 胡秋芬；

【导师】 陈景；

【作者基本信息】 昆明理工大学 ， 冶金物理化学， 2008， 博士

【摘要】 固相萃取技术是近几年来分析化学中新发展起来的一种样品前处理技术,其富集倍数高、可有效分离干扰、有机溶剂消耗小、环境污染小的特点非常适合用于复杂样品中低含量贵金属元素的测定和贵金属材料中低含量杂质元素的测定;我们还发现金氰络阴离子与与季铵阳离子可生成的疏水性的离子缔合物,可以被反相固相萃取柱高倍数富集,两种技术结合后的许多优点是传统的液-液萃取技术无法比拟的,在黄金提取中展现出良好的应用前景;因此本文首次研究了用固相萃取从碱性氰化液中萃取金和用固相萃取测定金及黄金制品中杂质元素,主要研究内容如下:（一）固相萃取从碱性氰化液中萃取金及机理研究（1）研究了溴化十六烷基三甲基铵（CTMAB）固相萃取从碱性氰化液中萃金,对CTMAB和金络阴离子生成离子缔合物的条件（溶液pH、CTMAB用量、辅助试剂的影响等）进行了研究;此外还研究反相固相萃取柱对C₁₆H₃₃N（CH₃）₃⁺·Au（CN）₂^-离子缔合物的固相萃取条件（包括固相萃取材料的选择,待萃取液中适合萃取的金浓度范围,过柱流速的选择、洗脱溶剂的选择和用量、固相萃取柱对离子对缔合物的萃取容量、富集倍数、回收率等）,结果表明:萃取液中CTMAB:Au的摩尔比为1.5:1较合理;在pH9.5-12范围内,pH值改变对金的萃取率无明显影响,可操作pH范围非常宽;待萃取液以20 mL/min的流速过柱,萃取容量可达23.6mg/g,当富集的金量为10 mg时,以5.0mL/min的流速用5 mL的乙醇可完全洗下,萃取回收率≥95%,金的浓度在1.0×10^-5-2.0×10^-4mol/L范围内,富集倍数可达100-1000倍;对于不同烷基键合材料,随着键合烷基碳链的增加,Au萃取回收率和柱萃取容量增加,C₁₈性能优于C₈、C₄和C₂。在研究CTMAB固相萃取萃金的基础上,还对四种类型（烷基三甲基铵盐型、二烷基二甲基铵盐型、烷基二甲基苄基铵型、吡啶鎓盐型）的表面活性剂和不同烷基碳链长度（十二烷基、十四烷基、十六烷基、十八烷基）的表面活性剂对金的萃取效果进行了比较,从萃取容量、富集倍数、可操作性等因素考虑,CTMAB和CPB综合性能优于D1622和HDBAB,碳链长度在C₁₂-C₁₈范围内时,碳链长度对金的萃取效果没有显著影响,综合考虑价格因素,烷基三甲基铵型的表面活性剂最理想,氯化物成本低于溴化物。（2）对萃取机理进行了初步的研究,制备了Au（CN）₂^-和C₁₆H₃₃N（CH₃）₃⁺的离子缔合物,并通过红外、核磁共振和质谱等鉴定了其结构;并用液相色谱法测定了缔合物和CTMAB疏水性差异;在借鉴前人研究工作的基础上,通过萃取前、后的反相键合硅胶固相萃取材料的扫描电镜分析和离子缔合物在萃取材料上的保留行为研究,初步确定了其萃取机理,即:CTMAB和Au生成了疏水性C₁₆H₃₃N（CH₃）₃⁺·Au（CN）₂^-离子缔合物,当样品溶液通过固相萃取柱时,由于溶剂分子（水）对待富集物（缔合物）的排斥作用和非极性固定相(C₁₈)对溶质分子（非极性分子）的吸附作用,缔合物被可逆的吸附在固定相上,改用洗脱剂洗脱时,由于溶剂对富集物（溶质分子）的排斥作用减少和富集物在非极性固定相上的亲和力减弱,富集物被洗脱下来。（二）放大实验、选择性及工艺流程初步确定（1）完成了初步的萃取放大实验,结果表明:随柱的扩大（填料用量增加）,柱能萃取金的量增加,但萃取容量随填料用量的增加而减小,放大后过柱流速随柱横截面积的增加而线性递增;随柱长的增加而线性递减;随柱的扩大,富集金量增加,所需洗脱液的体积也增加,基本呈线性关系;对于不同规格的柱,柱（直径/长度）在1/1到1/2之间萃取容量最大。试验了共存离子对金萃取的影响,结果表明银（Ⅰ）、铁（Ⅱ）、铜（Ⅰ）、镍（Ⅰ）、锌（Ⅱ）和钴（Ⅱ）的氰化物对金的萃取都有干扰,影响程度为:银（Ⅰ）＞铜（Ⅰ）≈镍（Ⅰ）≈锌（Ⅱ）＞钴（Ⅱ）＞铁（Ⅱ）。而且干扰具有加和效应,各元素同时存在比单一元素单独存在时更严重。在对实际矿山料液的萃取实验中,由于受到干扰元素的影响,金的萃取容量显著下降,金泥中金的品位仅为13.68%,方法的选择性和活性炭吸附相比没有显著改善。（2）完成了CTMAB对金的沉淀实验,在水介质中,缔合物溶解度小,仅为7.12μg/mL,在金浓度高时易生成沉淀;本论文研究了影响沉淀的相关因素,结果表明:介质pH和季铵盐的用量对离子缔合物溶解度影响不明显,而温度和介质中极性有机溶剂的比例对缔合物溶解度的影响很大,溶解度随温度的升高和随介质中有机溶剂比例的增加而显著增大。对于不同类型的季铵盐（烷基三甲基铵盐型、二烷基二甲基铵盐型、烷基二甲基苄基铵型、吡啶鎓盐型）,季铵盐的疏水基团越大,缔合物沉淀溶解度越小,顺序为D1622＜HDBAB＜CPB＜CTMAB;不同碳链长度（12,14,16,18）)的季铵盐生成缔合物沉淀的溶解度顺序为:OTMAB＜CTMAB＜TTMAB＜DTMAB,随碳链增长,溶解度减小。对从萃取洗脱液中回收金进行了初步实验,结果表明锌粉置换法、直接电沉积法,回收乙醇后的火法和湿法处理均可用于本实验的金回收,金回收容易实现。通过实验可初步确定本方法适合采用的工艺流程:碱性氰化液过滤,按Au:季铵盐比例为1:1.5加入季铵盐,然后供固相萃取用（如果Au浓度大于7.0μg/mL,先过滤（或离心）分离沉淀再萃取,分离出的沉淀可和洗脱后的金泥合并）。过完柱（柱吸附达到饱和）后用乙醇洗脱,洗脱液蒸馏回收乙醇（乙醇可返回使用）,回收乙醇后所得残渣（金泥）供精炼用。氰化液可继续返回使用。（三）固相萃取在金分析中的应用（1）研究了用5-（2-羟基-4-硝基苯偶氮）-硫代若丹宁（HNATR）固相萃取光度法测定金,在0.05-0.5 mol/L的磷酸介质中,乳化剂-OP存在下,HNATR与金反应生成3:1稳定络合物,该络合物可被聚合物键合固相萃取小柱萃取富集,小柱上富集的络合物用N,N-二甲基甲酰胺（DMF）洗脱,富集倍数达100倍,洗脱液用光度法测定,在洗脱液中,λmax=520 nm,体系摩尔吸光系数ε=1.37×10⁵L·mol^-1·cm^-1,金含量在0.01-3μg/mL内符合比尔定律,检测限达0.02μg/L。方法用于水样和矿石中金的测定,相对标准偏差为2.8%～3.5%,标准回收率为88%～96%,用电感耦合等离子体质谱ICP-MS作对照,结果与对照方法相符合。（2）研究了用载有TBP（磷酸三丁脂）的MCI-GEL反相树脂固相萃取富集,原子吸收分光光度法测定金,含金样品以1.0～6.0 mol/L的盐酸介质通超载有TBP的MCI-GEL反相树脂,金可被定量吸附在树脂上,柱上富集的金可用0.06 mol/L的亚硫酸钠溶液定量洗脱,富集倍数可超过100倍,洗脱液中的金用火焰原子吸收分光光度法测定,金含量在0.1～3.5μg/mL内符合比尔定律,检测限达5.0 ng/L;方法用于矿石和环境水样中金的测定,相对标准偏差在2.4%-2.8%之间,标准回收率在88%-104%之间,用电感耦合等离子体质谱ICP-MS作对照,结果与对照方法相符合。（3）研究了5-（2-羧基萘）-亚甲基若丹宁（CNR）柱前衍生,高效液相色谱法测定铂、钯、铑、金。在pH为3.5的醋酸-醋酸钠缓冲介质中,Triton X-100存在下,铂、钯、铑、金可和CNR反应生成稳定的络合物,该络合物可用Waters Sep-Pak C₁₈小柱固相萃取富集,小柱上富集的络合用N,N-二甲基甲酰胺（DMF）洗脱,富集倍数为100倍;经富集后的络合物用ZORBAX Stable Bound（4.6×50 mm,1.8μm）快速分离柱为固定相,54%的甲醇（内含0.1%的醋酸和0.1%的Triton X-100）为流动相,紫外二极管数组检测器检测测定,方法检测限为:金1.0μg/L、铂0.8μg/L、钯1.2μg/L、铑1.4μg/L。方法用于水样和矿石样品中金的分析,相对标准偏差为2.4%～3.6%,标准回收率为91%～95%,用电感耦合等离子体质谱ICP-MS作对照,结果与对照方法相符合。（四）在线固相萃取-高效液相色谱法测定氰化亚金钾中的杂质元素研究了在线固相萃取-高效液相色谱法测定氰化亚金钾中的杂质元素,氰化亚金钾样品用王水微波消解,在pH 7.0-9.5的缓冲介质中和乳化剂-OP存在下,样品中的银、铜、铁、铅、镍和锌等杂质元素可和2-（2-喹啉偶氮）-间苯二酚（QAR）生成稳定的络合物,络合物可用ZORBAX Stable Bound C₁₈（4.6×10mm,1.8μm）色谱柱在线固相萃取富集,然后以ZORBAX Stable Bound C₁₈（4.6×50 mm,1.8μm）色谱柱为固定相,65%的甲醇（内含0.01 mol/L pH=8.0的四氢吡咯-醋酸缓冲盐和0.1%乳化剂-OP）为流动相分离,二极管矩阵检测器检测测定;在选定色谱条件下,6种元素的络合物在2.5min内可达到完全分离;银、铜、铁、铅、镍和锌的检测限分别为:1.8、1.8、1.5、2.0、2.2、1.8 ng/L。方法用于电镀用氰化亚金钾样品分析,相对标准偏差在2.2-3.6%之间,标准回收率在91-104%之间,用电感耦合等离子体质谱ICP-MS作对照,结果与对照方法相符合。（五）微萃取分离-电感耦合等离子体质谱法测定高纯金中的杂质元素设计了微型萃取装置,并研究了用微型萃取分离,电感耦合等离子体质谱（ICP-MS）法测定高纯金中的银、铜、铁、铅、锑和铋6种杂质元素。纯金样品用微波消化,在盐酸介质用甲基异丁基酮（MIBK）萃取分离金基体;然后用ICP-MS测定,以Sc,Y,In作为内标物质,补偿了基体效应;通过选择适当的待测元素同位素克服了质谱干扰,确定了最佳测定条件。在选定测定条件下,6种杂质元素的检出限在0.006-0.01μg/L之间;线性关系良好,相关系数r≥0.9992;方法用于实际样品分析,回收率在91%-98%之间:RSD＜3.0%。而且本方法的微型液-液萃取实现了贵金属样品分析的微处理,仅取0.1左右的样品就可满足于痕量杂质元素的分析,和其它方法相比大大减少了样品取样量,节约了分析成本。更多还原

【Abstract】 The solid phase extraction technique got a rapid development because of its obvious advantages.The higher enrichment factors,absence of emulsion,low organic solvent consumption and environment friendly of solid phase extraction make this technique adapt to determination of noble metal ions in complex matrices,and determination of trace impurities in noble metal material.We find that the complex cation of gold can reacts with quaternary ammonium salt to form a hydrophobic ion association.The ion association can be preconcentrated by solid phase with high enrichment factor.This show the solid phase extraction has good application prospects in gold extraction.In this dissertation,the application of solid phase exaction in the fields of extraction of gold from cyanide solution, trace gold determination and trace impurities determination in gold products were studied. The main research works are listed as follow:（Ⅰ）Study on the extraction of gold from cyanide solution by solid phase exaction.（1）The extraction of gold from cyanide solution by solid phase exaction with cetyl trimethylammonium bromide（CTMAB）was studied.The condition for the formation of ion association（the pH of solvent,the amount CTMAB used,the accessory reagent used,et al）and the condition for solid phase extraction of the ion association（the extraction sorbents,the capacity of the cartridge,the enrichment factor,the recovery of gold,et al） were carefully studied.The results show that the reasonable conditions are the molar ratio of CTMAB:Au 1:1,pH 9.5-12,sample flow rate 20 mL/min.The capacity of the cartridge for gold extraction reaches 23.6 mg/g under this condition.The enriched gold was eluted from the cartridge with 5.0 mL of ethanol as eluent.The enrichment reaches 100-1000 times for 1.0×10^-5～2.0×10^-4mol/L of gold solutions.The effects of reversed phase sorbents(C₂,C₄,C₈,C₁₈)on gold extraction were studied.The results show that C₁₈has the best effect.The effects of various quaternary ammonium salts on gold extraction were also studied.The alkyltrimethyl ammonium type quaternary ammonium salts has the best effect. The optimal reagents for gold extraction are tetradecyl trimethyl ammonium chloride,cetyl trimethyl ammonium chloride or dodecayl trimethyl amine chloride. The mechanisms of the gold extraction with quaternary ammonium salts by solid phase extraction were studied.The ion association of CTMAB with Au（CN）₂^- was synthesized,and it structure was verified by IR,¹HNMR and MS.The high performance liquid chromatography analysis show that the hydrophobicity of the ion association is strong than that of CTMAB.The images of the sorbent and the sorbent which absorbed gold were obtained by scanning electron microscope,and the retention behaviors of ion association on octadecyl silane(C₁₈)were studied.By the above experipents and the previous work reported,the mechanisms of the gold extraction were proposed.The CTMAB can reacts with Au（CN）₂^- to form a hydrophobie ion association.When the ion association solution passing the extraction cartridge,the solvents molecular（water）gives a repelling force to the ion association,and the non-polar stationary phase(C₁₈)has an adsorption to the ion association.The ion association was reversibly absorbed onto the C₁₈. When using organic solvent as eluant,the repelling force to ion association,and affability of C₁₈to ion association decreased markedly,and the ion association which absorbed on C₁₈ can be eluted from the cartridge.（Ⅱ）The scale-up experiment,selective experiment,and the elementary procedure for extraction.（1）The scale-up experiment was carried out.The results show that the amount of gold extraction increase with the increasing of sorbent amount.However,the capacity of the gold extraction decrease with the increasing of sorbent amount.The sample flow rate linearly increase with the increasing of cartridge cross sections.The sample flow rate linearly decrease with the increasing of cartridge length.The eluant needed linearly increase with the increase of the gold amount absorbed on the cartridge.For various different type cartridges,the diameter to length ranged to 1:1-1:2 have the largest extraction capacity to gold.The effect of interfering ions on gold extraction was studied. The results show that Ag（Ⅰ）,Fe（Ⅱ）,Cu（Ⅰ）,Ni（Ⅰ）,Zn（Ⅱ）,Co（Ⅱ）can interfere the gold extraction.The interfering orders are Ag（Ⅰ）＞Cu（Ⅰ）≈Ni（Ⅰ）≈Zn（Ⅱ）＞Co（Ⅱ）＞Fe（Ⅱ）.The interference of these ions has a synergistic effect when they simultaneously existed.The extraction of gold from typical cyanide solution was also studied.The results show that the gold extraction capacity decreas ripadly because of interfering ions exised.The gold mud obtained contain 13.68%gold.This indicated that the selectivity of solid phase extraction method is not obviously improved compared to that of activated carbon adsorption method.（2）The precipitating of gold with CTMAB in cyanide solution was studied.The ion association of CTMAB with Au（CN）₂^- has low solubility in water solution,only 7.12μg/mL.The precipitation can formed when gold contraction above 7.12μg/mL at 25℃. we carefully studied the factors which affects the ion association solubility.The medium pH does not affects the solubility.However,the temperature and the organic solvent in medium greatly affect the solibility.The solibility was increased markedly with the increasing of temperature and increasing the organic solvent proportion in medium.The effect of various different quaternary ammonium salts to precipitate gold was studied.The solubility orders are D1622＜HDBAB＜CPB＜CTMAB and OTMAB＜CTMAB＜TTMAB＜DTMAB. Because the ion association has low solubility,the ion association solution should be filtrated when the gold concentration above 7.12μg/mL.The recovery of gold from eluant was also studied.The results show that the recovery of gold can be achieved by zinc dust precipitation method,direct electrodeposition method,and hydrometallurgy or thermometallurgy when ethanol evaporated.（3）By above experimients,the reasonable procedure for gold extraction was primary identified.The quaternary ammonium salts was added to the cyanide solution.This solution was applied to solid phase extraction（The solution was filtered when the gold concentration above 7.12μg/mL）.After the extraction finished（The gold absorption attains saturation）,the cartridge was eluted with ethanol.The ethanol in eluant was recoveried by distillation,and the gold mud was obtained.The gold mud was afforded to refining,and the residual cyanide solution can be afforded to cyanide leaching again.（Ⅲ）The applacition of solid phase extraction in gold determinationA new method for the determination of gold based on the color reaction of gold with 5-（2-hydroxy-4-nitrophenylazo）-thiorhodanine（HNATR）and the solid phase extraction of the colored chelate with a reversed phase polymer-based C₁₈cartridge was developed.In the presence of 0.05-0.5 mol/L of phosphoric acid solution and emulsifier-OP medium,HNATR reacts with gold to form a red chelate of a molar ratio 1:3（gold to HNATR）.This chelate was enriched by the solid phase extraction with a polymer-based C₁₈cartridge and eluted the chelate from the cartridge with dimethyl formamide（DMF）.The enrichment factor of 100 was achieved.In the DMF medium,the molar absorptivity of the chelate is 1.37×10⁵ L.mol^-1.cm^-1at 520 nm.Beer’s law is obeyed in the range of 0.01～3μg/mL in the measured solution.The detection limit,based on the three times of standard deviation is 0.02μg/L in the original sample.This method was applied to the determination of gold in water and ore with good results.The relative standard deviations are 2.8%-3.5%.The standard recoveries are 88%-96%.The determination results are agreed with that of reference method （ICP-MS method）.The solid phase extraction and flame atomic absorption spectrometry method for the determination of gold using MCI GEL reversed phase resin loaded with TBP as sorbent was studied.The gold was quantitatively absorbed on the MCI GEL resin when the sample solution pass the cartridge as 1.0-6.0 mol/L hydrochloric acid medium.The absorbed goht was eluted from the cartridge with 0.06 mol/L sodium sulphite solution as eluant.The enrichment factor above 100 was achieved.The gold in eluant was determination by flame atomic absorption spectrometry method.Beer’s law was obeyed in the range of 0.1～3.5μg/mL.The detection limit reaches 5.0 ng/L.This method was applied to the determination of gold in ore and water samples.The relative standard deviations are 2.4%-2.8%,and the recoveries are 88%-104%.The determination results are agreed with that of reference method（ICP-MS method）.A new method for the simultaneous determination of palladium,platinum,rhodium and gold by solid phase extraction and high performance liquid chromatography using 2-carboxyl-1-naphylidene rhodanine（CNR）as pre-column derivatization reagents was studied.In the presence of pH 3.5 acetic acid-sodium acetate buffer solution and triton X-100 medium,the palladium,platinum,rhodium and gold ions were reacted with CNR to form colored chelates.The Pd-CNR,Pt-CNR,Rh-CNR and Au-CNR chelates were enriched by solid phase extraction with Waters Sep-Pak C₁₈cartridge.The enrichment factor of 100 was achieved by eluting the retained chelates from the cartridge with DMF.These chelates were separated on a ZORBAX Stable Bound rapid analysis column（4.6×50 mm,1.8μm） with 54%methanol（containing 0.1%of acetic acid and 0.1%of Triton X-100）as mobile phase and detected with a photodiode array detector from 400～600 nm.The palladium, platinum,rhodium and gold chelates were separated completely within 2.5 min.The detection limits（S/N=3）of palladium,platinum,rhodium and gold reaches 1.2μg/L,0.8μg/L,1.4μg/L and 1.0μ/L,respectively.This method was applied to the determination of palladium,platinum,rhodium and gold in water and geological samples.The relative standard deviations were 2.4%-3.6%.The standard recoveries were 91%-95%.The determination results are agreed with that of reference method（ICP-MS method）.（Ⅳ）Simultaneous determination of trace impurities in gold potassium cyanide for electroplating by on-line solid phase extraction and high performance liquid chromatographyA new method for the simultaneous determination of trace impurities in gold potassium cyanide for electroplating was developed by high performance liquid chromatography equipped with on-line solid phase extraction technique.The samples were digested with aqua regia by microwave acid-digestion.The silver,copper,iron,lead,nickel and zinc ions in the digested samples were pre-column derivatized with 2-（2-quinolinylazo）-resorcin（QAR）to form colored chelates in pH 7.0-9.5 buffer solution and emulsifier-OP medium.The Ag-QAR,Cu-QAR,Fe-QAR,Pb-QAR,Ni-QAR and Zn-QAR chelates can be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column[Zorbax Stable Bound,10 mm×4.6 mm,1.8μm]with a buffer solution of pH 8.0 pyrrolidine-acetic as mobile phase. After the enrichment had finished,by switching the six ports switching valve,the retained chelates were back-flushed by mobile phase and traveling towards the analytical column. These chelates separation on the analytical column[Zorbax Stable Bound,10 mm×4.6 nun,1.8μm]was satisfactory with 65%methanol（containing 0.01 mol/L of pH 8.0 pyrrolidine-acetic buffer salt and 0.1%of emulsifier-OP）as mobile phase.The Ag-QAR, Cu-QAR,Fe-QAR,Pb-QAR,Ni-QAR and Zn-QAR chelates were separated completely within 2.5 min.The detection limits（S/N=3）of silver,copper,iron,lead nickel and zinc reaches 1.8 ng/L,1.8 ng/L,1.5 ng/L,2.0 ng/L,2.2 ng/L and 1.8 ng/L,respectively.The method was applied to the determination of silver,copper,iron,lead,nickel and zinc in gold potassium cyanide for electroplating.The relative standard deviations were 2.2%-3.6%,and the standard recoveries were 91%-104%.The determination results are agreed with that of reference method（ICP-MS method）.（Ⅴ）Determination of trace impurities in gold by minitype extraction and inductively coupling plasma-mass spectrometryIn this work,a minitype extraction device was designed,and the determination of trace impurities（silver,copper,iron,lead,stibium and bismuth）in gold by minitype extraction and inductively coupling plasma-mass spectrometry（ICP-MS）was studied.The gold samples were digested in qua regia with a microwave oven,and the silver,copper,iron, lead,stibium and bismuth were separated from gold by minitype extraction using methyl isobutyl ketone as extraction reagent.The impurities in gold were determined by ICP-MS, and the Sc,Y,In were added as internal standards to eliminate the matrix interferences.The results show that the relative standard deviations for silver,copper,iron,lead,stibium and bismuth were below 3.0%,the standard recoveries of these elements were in the range of 91%-98%,and the detection limits were in the range of 0.006-0.01μg/L.By minitype extraction,only 0.1g of samples was needed for the determination of impurities.Compared to routine method,the samples consumption was markedly decreased,and the cost for analysis was markedly saved.更多还原