(1. 太原理工大學(xué) 化學(xué)化工學(xué)院，太原 030024； 2. 中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083)
摘 要: 采用焦亞硫酸鈉復(fù)合還原沉金后液回收硒、碲和捕集金、鉑、鈀。通過正交實驗考察各因素對硒、碲、金、鉑、鈀還原率的影響，并對焦亞硫酸鈉、SO2和水合肼復(fù)合還原沉金后液進行動力學(xué)及熱力學(xué)特征分析。結(jié)果表明：采用焦亞硫酸鈉、SO2和水合肼復(fù)合還原沉金后液，對硒、碲還原率的影響從大到小的順序為反應(yīng)時間、焦亞硫酸鈉用量、水合肼用量。通入 SO2至飽和后，當(dāng)水合肼用量為1.5 mL/L，焦亞硫酸鈉為30 g/L，SO2流量為0.4 L/min，每反應(yīng)1h通入0.5 h SO2，反應(yīng)時間為9 h時，金、鉑、鈀的還原率均達到100%，硒和碲的還原率分別為71.50%和90.30%。焦亞硫酸鈉復(fù)合還原硒、碲符合一級反應(yīng)動力學(xué)規(guī)律，還原硒、碲的表觀活化能分別為52.533 kJ/mol和70.828 kJ/mol，硒、碲的還原屬化學(xué)反應(yīng)控制。熱力學(xué)分析表明，沉金后液中金、鉑、鈀、硒、碲分別以AuCl4-、PtCl42-、PdCl42-、H2SeO3、TeCl62-形態(tài)存在，焦亞硫酸鈉、SO2主要以H2SO3形態(tài)存在，水合肼以N2H5+形態(tài)存在。
關(guān)鍵字: 沉金后液；焦亞硫酸鈉；正交實驗；熱力學(xué)；動力學(xué)
（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
