本文選題：低共熔溶劑　切入點(diǎn)：鉻粉　出處：《哈爾濱工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本論文主要研究了在新型離子液體即低共熔溶劑(deep eutectic solvents,DESs)體系中,電解鉻的陰極沉積、陽極溶解和同時(shí)電解的工藝條件,并對低共熔溶劑的性質(zhì),鉻電化學(xué)反應(yīng)的機(jī)理進(jìn)行了探究。本論文首先對低共熔溶劑的電化學(xué)性質(zhì)進(jìn)行了分析,分別測定其熔點(diǎn)Tf、電導(dǎo)率σ、粘度η、電化學(xué)窗口等性質(zhì),分析表明,低共熔溶劑的電導(dǎo)率與粘度與氫鍵供體的性質(zhì)有關(guān),氯化膽堿與乙二醇制備的DESs電導(dǎo)率最高,σ=17.72m S/cm,其電化學(xué)窗口為3.36 V,最適用于電沉積體系。通過陰極沉積的工藝試驗(yàn)中發(fā)現(xiàn),草酸與氯化銨共同做添加劑時(shí),鉻沉積效果不如單獨(dú)使用好,溫度對沉積過程影響顯著,其主要原因是電導(dǎo)率受溫度的影響較大。陰極沉積最優(yōu)工藝條件為:反應(yīng)溫度353 K,電流密度450 A/m2,電解時(shí)間1 h,攪拌速率300 rpm,陰極電流效率為14.01%。在陽極溶解鉻錠的試驗(yàn)中發(fā)現(xiàn),酸類添加劑的陽極電流效率要比堿類添加劑高很多,陽極溶解受溫度的影響最大,且攪拌速率對槽壓和電流效率的影響也較大。該工藝所得到的最高的陽極電流效率為73.94%。該體系在同時(shí)電解時(shí),只有溫度和陰極電流密度的影響具有顯著性,該工藝的陰陽極電流效率分別達(dá)到16.94%和70.23%。本論文在低共熔溶劑中成功對同時(shí)電解鉻工藝進(jìn)行了探索性的研究,陽極電流效率基本均在70%以上。通過循環(huán)伏安曲線確定了鉻還原為不存在前置反應(yīng)的不可逆過程,并通過不同溫度下的穩(wěn)態(tài)極化曲線求出反應(yīng)的活化能、陰陽極傳遞系數(shù)、反應(yīng)級數(shù)等參數(shù)。確定了反應(yīng)的活化能為14.446 k J/mol,并且鉻的反應(yīng)為擴(kuò)散控制。并分別對陰陽極測定其極化曲線,通過對陽極極化曲線的分析發(fā)現(xiàn),升高溫度可以減弱陽極鈍化,即促進(jìn)陽極溶解的進(jìn)行。
[Abstract]:This paper mainly studies the model in ionic liquid eutectic solvents (deep eutectic solvents, DESs) system, the cathode electrolytic chromium deposition, anodic dissolution and electrolysis process conditions at the same time, and the properties of eutectic solvents, the electrochemical reaction mechanism of chromium was discussed. Firstly, electrochemical properties the eutectic solvents were analyzed, the melting point of Tf, were measured by conductivity sigma, viscosity, electrochemical window properties analysis showed that the eutectic solvent viscosity and conductivity and hydrogen bond donor properties, choline chloride and ethylene glycol prepared DESs highest conductivity Sigma =17.72m S/cm, the electrochemical window 3.36 V, the most suitable for the electro deposition system. Through the process test found in the cathodic deposition, oxalic acid and ammonium chloride as common additives, as chromium deposition effect alone, the effect of temperature on the deposition process was the main The reason is greatly influenced by the temperature. The conductivity of the cathode deposition of optimal process conditions: reaction temperature 353 K, current density of 450 A/m2, electrolytic time is 1 h, stirring rate of 300 rpm, the cathodic current efficiency of 14.01%. found in the test of anodic dissolution of chromium ingot in acid additive anode current efficiency is much higher than the base class additive, anode dissolution is affected by temperature, and the effect of stirring speed on the cell voltage and current efficiency is higher. By this process the highest anode current efficiency of 73.94%. system in the simultaneous electrolysis, affecting only temperature and cathodic current density was significant, the process of cathode and anode current efficiency respectively. 16.94% and 70.23%. in this paper, the eutectic solvents and success of electrolytic chromium process was studied, the anode current efficiency was above 70%. Determined by cyclic voltammetry There is no pre chromium reduction reaction irreversible process, and by steady-state polarization curves at different temperatures and the activation energy of the reaction, anode transfer coefficient, reaction parameters were determined. The reaction activation energy of 14.446 K J/mol, and the reaction of chromium is diffusion controlled. And the determination of the Yin and Yang the polarization curve, through the analysis of the anodic polarization curve, increasing temperature can weaken the anodic passivation, which accelerate the anodic dissolution.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ153

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本文編號：1601168