【作者】 刘晓荣；

【导师】 邱冠周； 胡岳华；

【作者基本信息】 中南大学 ， 矿物加工工程， 2001， 博士

【摘要】 为优化德兴铜矿生物浸出—溶剂萃取—电积（BL—SX—EW）提铜技术，系统研究了铜溶剂萃取界面乳化成因、形成和稳定机制及其预防措施，考察了界面乳化、萃余液夹带等乳化现象对生物浸矿过程的危害。 含有复杂毒性和表面活性物质的萃取有机相由于夹带流失于萃余液中，通过循环造成细菌浸矿系统污染，使细菌的生长周期延长4天，浸出24天的铜浸出量降低20％。界面乳化液的富集作用使浸矿细菌浓度不断降低。本文提出了改善细菌浸矿效率的相应措施。 运用气质联用分析、扫描电镜、X—射线衍射、原子吸收光谱等手段分析研究了界面乳化物的成因。结果表明，铜溶剂萃取界面乳化物形成的主要诱因是有机相中表面活性物质和体系中固体微粒。循环有机相中积累了大量稠环芳烃类杂质和含有羰基、羧基、羟基、酰胺基的两亲性降解产物。Lix84有效成分和壬基酚在长期循环过程中由于发生贝克曼重排、水解、氧化、磺化等反应而严重降解，它们的化学稳定性比Lix86ON差。固体微粒主要由未分解矿石微粒（如硅酸盐粘土、SiO₂）、萃原液中水解产生的胶体微粒（如Fe（OH）₃、SiO₂胶体）和萃取过程中产生的饱和硫酸盐沉淀（如CaSO₄·2H₂O）等组成。 研究了Lix984N、稀释剂性质、有机相中杂质和降解产物、固体微粒等对萃取分相，性能和界面乳化行为的影响。随Lix984N浓度增加，有机相粘度增加，界面张力和两相密度差降低。由Shinner理论推导出的液滴附着能与体系物性的关系A（h₀）=[c·γ^0.6ρ_c^-0.108Δρ^-0.117ν⁽-0.05]₃⁸证明，体系物理性质随Lix984N的改变促使相分离速度降低，液滴聚结阻力增加。用基团法算出Lix984N的HLB值为1.29，它利于W/O型乳化液的稳定，在O/W型界面乳化物形成过程中起协同乳化作用。在本实验条件下Lix984N体积分数为5％左右为界面乳化液转型区。 固体微粒是诱发界面乳化的决定性因素。随萃原液中固体微粒含量增加，界面乳化程度加重，乳化液滴粒度减小，分布变窄，乳化液变得更稳定。固体微粒除形成坚固致密的界面膜稳定乳化液滴外，还形成微粒絮团在液滴间隙中填充，隔离分散相液滴，使其难以运动、聚结。 研究发现，液滴间静电斥力和水化斥力的稳定效应、乳化液中三维网状结构对液滴聚结的机械障碍作用以及多相复合界面膜的稳定作用是界面乳化液稳定的中南大学博士论文 铜溶剂举取界面乳化机理及防治研究三个主要因素。本文详析了多相复合界面膜的结构特征和稳定机理，描述了界面乳化液聚结破坏的横向位移模型和极限聚结现象。指出固体膜稳定的乳化液滴间的相互作用力需用扩展的DLVO理论才能正确描述。 针对界面乳化液的成因、稳定机理和体系特点，设计研究了过量硫酸磺化法和添加低分子极性有机物DA的防乳化措施，分别取得了良好效果。如一定条件下加入最佳用量的DA后，分相时间缩短了27．3％，乳化液滞留分率减少了86．7％，静置5小时的自然破乳率增加了近3倍。更多还原

【Abstract】 In order to optimize the performance of copper bioleaching- solvent Extraction-electrowinning process (BL-SX-EW) at DeXing Copper Mine in Jiangxi Province, the bacteriostasis of organic phase entrained in the aqueous raffinate and the aspects of interfacial emulsions (also called interfacial crud) in copper-SX circuit, such as causes and mechanisms of stable emulsion formation and methods used to prevent emulsification are studied systematically.The entrainment of organic phase in the aqueous raffinate of copper-SX results in pollution in bioleaching system through circle performance. The activity and leaching ability of bacteria is deteriorated seriously because there are more kinds of bactericides and surfactants in organic phases, such as phenol and naphthalene. As a result, growing period of bacteria is delayed by 4 days and leaching copper concentration in 24 days decreased by 20%. The concentration of bacteria declines constantly as a result of collection by interfacial emulsion. Some effective ways to enhance bioleaching efficiency are suggested.A lot of analyze and examination results, such as GOMS, XRD, SEM and AAS reveal that impurities and surfactants in organic phase and solid particles in copper-SX system can be mostly related to 0/W type of interfacial emulsions formation. Many kinds of amphiphiles containing such hydrophilic group as carbonyl, carboxyl, hydroxyl or acylamine produced in the reagent degradations and dense-aromatic impurities originated from diluent are accumulated in organic phase, being as one kind of emulsifying agent stabilizing droplets. The effective compositions of Lix84 and nonylphenol are degraded almost completely after long term circulation by Beckmann rearrange, hydrolyzing, oxidizing and sulfonating reactions, so they are less stable then the effective compositions of Lix860N. Another kind of emulsifying agent is the solid particles that consist of mineral particles suspended in the aqueous feed (for example silicate or quartzparticles), Fe(OH)3 and Si02 colloids in the aqueous feed and sulfate precipitated in the extraction operation.The effects of Lix984N, diluent, circulating organic phase, solid particles on disengagement properties and interfacial emulsion performance are studied respectively. With increase of Lix984N concentration, the viscosity of organic phase increases and interfacial tension and density difference between two immiscible liquids decreases. The relationship between adhesion force of two equal droplets separated by a distance h() and physical properties of system can be described as, which is deduced from Shinner theory. Thisequation infers that the changes of physical properties of organic phase with Lix984N concentration make the disengagement of two phases slower and the resistance to droplets coalescence stronger. The HLB value of Lix984N calculated by Davies’ incremental approach is 1.29 in favor of the stability of W/0 type emulsion. Lix984N play a cooperating role during 0/W type interfacial emulsion formation in copper-SX. Interfacial emulsion tends to transform type from 0/W to W/0 when the volume factor of Lix984N is at about 5% under our experimental conditions.Among two kinds of: the emulsifying agents, solid particles in the system are believed to be the predominating one for emulsion formation and stability. Experimental results show that the higher of solid particle content in aqueous feed the more interfacial emulsion come into being with smaller diameter and narrower distribution of droplets, as a result interfacial emulsion becomes more stable. In addition to forming compact solid skins stabilizing emulsion droplets, the particle floccules will fill spaces between droplets so that droplets are separated and protected against moving and coalescence.According to experimental results we believe the interfacial emulsion stability depends on three primary factors: one is the repulsion effect of electrostatic and hydration forces, the second-is the mechanical barrier of three-dimensional network structure in更多还原