(1. 太原理工大学 化学化工学院，太原 030024； 2. 中南大学 冶金与环境学院，长沙 410083)
摘 要: 采用焦亚硫酸钠复合还原沉金后液回收硒、碲和捕集金、铂、钯。通过正交实验考察各因素对硒、碲、金、铂、钯还原率的影响，并对焦亚硫酸钠、SO2和水合肼复合还原沉金后液进行动力学及热力学特征分析。结果表明：采用焦亚硫酸钠、SO2和水合肼复合还原沉金后液，对硒、碲还原率的影响从大到小的顺序为反应时间、焦亚硫酸钠用量、水合肼用量。通入 SO2至饱和后，当水合肼用量为1.5 mL/L，焦亚硫酸钠为30 g/L，SO2流量为0.4 L/min，每反应1h通入0.5 h SO2，反应时间为9 h时，金、铂、钯的还原率均达到100%，硒和碲的还原率分别为71.50%和90.30%。焦亚硫酸钠复合还原硒、碲符合一级反应动力学规律，还原硒、碲的表观活化能分别为52.533 kJ/mol和70.828 kJ/mol，硒、碲的还原属化学反应控制。热力学分析表明，沉金后液中金、铂、钯、硒、碲分别以AuCl4-、PtCl42-、PdCl42-、H2SeO3、TeCl62-形态存在，焦亚硫酸钠、SO2主要以H2SO3形态存在，水合肼以N2H5+形态存在。
关键字: 沉金后液；焦亚硫酸钠；正交实验；热力学；动力学
（1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China; 2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Selenium and tellurium were recovered from precipitated gold solution by the compound of Na2S2O5. At the same time, gold, platinum and palladium were also captured. In order to determine the optimum process parameters, three main effect factors were investigated by an orthogonal experiment. The thermodynamic and dynamic characteristics of reducing precipitated gold solution by Na2S2O5, SO2 and N2H4 compound were analyzed. The study shows that: the influence factors on reduction rate of Se and Te decrease in such an order: reaction time, the amount of Na2S2O5, the amount of N2H4. When SO2 is bubbled to saturation , the amount of Na2S2O5 is 30 g/L, the amount of N2H4 is 1.5 mL/L, reaction temperature is 85 ℃, SO2 is passed into solution intermittently, the time for SO2 passing into solution is 0.5h after one hour per reaction, the flow rate of SO2 is 0.4 L/min, reaction time is 9 h, the reduction rates of Au, Pt, Pd are 100%, the reduction rates of Se and Te are 71.50% and 90.30%, respectively. The reaction of Na2S2O5 compound reducing Se and Te follows First-order kinetics. The apparent activation energy of reducing Se and Te which is controlled by chemical reaction is determined to be ESe=52.533 kJ/mol and ETe=70.828 kJ/mol. The analysis of thermodynamic characteristics shows that, Se, Te, Au, Pd and Pt exit in the form of AuCl4-, PtCl42-, PdCl42-, H2SeO3 and TeCl62-, respectively. Sodium metabisulfite and SO2 exit mainly in the form of H2SO3, hydrazine hydrate exits in the form of N2H5+.
Key words: precipitated gold solution; N2H5+; orthogonal experiment; thermodynamics; kinetics
