本文選題：硫代硫酸鹽　切入點(diǎn)：浸金　出處：《昆明理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：硫代硫酸鹽作為一種能替代氰化物的最有應(yīng)用前景的無毒浸金試劑被廣泛關(guān)注。但是,多數(shù)研究者采用的銅氨硫代硫酸鹽浸金體系存在試劑耗量大且氨對環(huán)境有污染等缺點(diǎn)。用多胺來代替氨水,可以保持硫代硫酸鹽浸金效率的同時(shí)大幅降低硫代硫酸鹽的消耗量,但體系中銅絡(luò)離子、游離銅離子對金的溶出過程的影響尚不清楚。本文采用電化學(xué)中的塔費(fèi)爾(Tafel)曲線研究硫代硫酸鹽浸金體系中銅離子濃度、硫代硫酸鹽濃度和不同配體對金腐蝕電流密度、腐蝕電位、腐蝕電阻的影響；采用線性伏安掃描(LSV)曲線研究浸金體系中銅離子濃度、硫代硫酸鹽濃度對峰電位和峰電流的影響,從而得出上述單因素對金溶解性能的影響。采用電化學(xué)阻抗譜(EIS)曲線來研究胺(氨)硫代硫酸鹽浸金體系中銅離子濃度、硫代硫酸鹽濃度和不同配體對極化電阻及其動力學(xué)行為影響,進(jìn)而推測銅離子及其絡(luò)合物對金溶出過程的影響。Tafel和LSV研究表明：分別以氨、乙二胺為配體時(shí),隨著銅離子濃度的增加,金腐蝕電位降低,極化電阻減��；金腐蝕電流密度和峰電位增大,峰電流增加,這說明銅離子能加快金的溶蝕速率。在銅離子濃度為0.0002mol/L～0.0008mol/L時(shí),反應(yīng)級數(shù)為1。但硫代硫酸鹽對金溶出的電化學(xué)過程影響較為復(fù)雜。兩種浸金體系對比發(fā)現(xiàn),乙二胺浸金體系比氨浸金體系使金更易于溶蝕,且溶蝕速率更快。EIS研究表明,在銅氨浸金體系,當(dāng)銅離子濃度為0～0.0008mol/L時(shí),控制浸金反應(yīng)速率的步驟主要為電荷轉(zhuǎn)移控制,當(dāng)銅離子濃度介于0.0008mol/L～0.002mol/L時(shí),控制反應(yīng)速率的步驟主要為電荷轉(zhuǎn)移控制和擴(kuò)散控制同時(shí)進(jìn)行,當(dāng)銅離子濃度介于0.002mol/L～0.008mol/L時(shí),控制反應(yīng)速率的步驟主要為擴(kuò)散控制；對銅乙二胺浸金體系中的當(dāng)銅離子濃度介于0.0001 mol/L～0.006mol/L時(shí),控制浸金反應(yīng)速率的步驟主要為電荷轉(zhuǎn)移控制；當(dāng)銅離子濃度介于0.006mol/L～0.0008mol/L時(shí),控制反應(yīng)速率的步驟主要為電荷轉(zhuǎn)移控制和擴(kuò)散控制同時(shí)進(jìn)行。結(jié)合浸金體系中銅(Ⅱ)分布狀態(tài)和金溶出的控制步驟分析表明,在一定范圍內(nèi)溶液中游離銅離子與金之間的電子交換速率對金的氧化溶出起主要作用。
[Abstract]:Thiosulfate, as one of the most promising non-toxic gold leaching reagents that can replace cyanide, has attracted wide attention. The copper thiosulfate leaching system used by most researchers has many disadvantages, such as high reagent consumption and ammonia pollution to the environment. Using polyamines instead of ammonia water can keep the efficiency of gold leaching by thiosulfate and reduce the consumption of thiosulfate significantly. However, the effect of copper complex ion and free copper ion on the dissolution process of gold is not clear. The concentration of copper ion in thiosulfate leaching system is studied by using the Tafel curve of electrochemistry. The effects of thiosulfate concentration and different ligands on the corrosion current density, corrosion potential and corrosion resistance of gold were studied by using linear voltammetry scanning spectroscopy (LSVV) curve to study the effects of copper ion concentration and thiosulfate concentration on peak potential and peak current in gold leaching system. The influence of the single factor on the dissolution of gold was obtained. The concentration of copper ion in the gold leaching system was studied by using the electrochemical impedance spectroscopy (EIS) curve, and the electrochemical impedance spectroscopy (EIS) curve was used to study the concentration of copper ion in the gold leaching system. The effects of thiosulfate concentration and different ligands on polarization resistance and kinetic behavior were deduced. Tafel and LSV studies showed that when ammonia and ethylenediamine were used as ligands, the effects of copper ions and their complexes on the dissolution process of gold were deduced. With the increase of copper ion concentration, the corrosion potential of gold decreases, the polarization resistance decreases, the current density and peak potential of gold increase, and the peak current increases, which indicates that copper ion can accelerate the dissolution rate of gold. When the concentration of copper ion is 0.0002mol / L, 0.0008 mol / L, The order of reaction is 1. However, the influence of thiosulfate on the electrochemical process of gold dissolution is more complicated. The comparison between the two gold leaching systems shows that the gold leaching system of ethylenediamine is easier to dissolve than the gold leaching system of ammonia, and the dissolution rate is faster. In the copper ammonia gold leaching system, when the concentration of copper ion is 0.0008 mol / L, the main step to control the gold leaching rate is charge transfer control, and when the copper ion concentration is 0.0008 mol / L, 0.002 mol / L, The steps of controlling the reaction rate are charge transfer control and diffusion control. When the concentration of copper ion is 0.002 mol / L ~ 0.008 mol / L, the main step of controlling the reaction rate is diffusion control. When copper ion concentration is 0. 0001 mol/L~0.006mol/L, charge transfer control is the main step to control gold leaching rate in copper ethylenediamine gold leaching system, and when copper ion concentration is 0. 006 mol / L ~ 0. 0008 mol / L, The main steps to control the reaction rate are charge transfer control and diffusion control. The electron exchange rate between free copper ion and gold in a certain range plays an important role in the oxidation dissolution of gold.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TD953

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