次氯酸钠浸金电化学及难浸金矿浸出实验研究
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摘要
用恒电位仪测定了不同次氯酸钠浓度和pH的条件下金阳极溶解极化曲线,拟合得到自腐蚀电位(Ecorr)、自腐蚀电流密度(Icorr)以及线性极化电阻(Rp),并进行难浸金矿的搅拌浸出验证实验。结果表明,在不同浓度条件下金腐蚀速率先增大后减小,在浓度0.75 mol/L时金阳极开始钝化,浸出实验结果与电化学研究结果一致;不同pH实验条件下金的腐蚀速率随pH增加而逐渐增大,但pH超过12后浸出率稍有下降,浸金结果与电化学研究结论略有不同。
The polarization curves of gold anodic dissolution under different concentration conditions of sodium hypochlorite and pH values were measured by using a potentiostat,and the self-corrosion potential(Ecorr),the self-corrosion current density(Icorr) and the linear polarization resistance(Rp) were calculated by the curve-fitting method.These parameters were subjected to the verification of actual leaching process of a refractory gold ore.The results showed that the gold corrosion rate first increased and then decreased with the augment of sodium hypochlorite concentrations.The gold anode started to passivate at the concentration of 0.75 mol/L.The outcomes of the actual leaching experiments were in good agreement with the electrochemical profile.The corrosion of gold accelerated with the increase of pH values,resulting in an increase of the leaching rate.However,the leaching rate would decreased slightly after the pH value exceeded 12,which is slightly different from the results of the electrochemical studies.
The polarization curves of gold anodic dissolution under different concentration conditions of sodium hypochlorite and pH values were measured by using a potentiostat,and the self-corrosion potential(Ecorr),the self-corrosion current density(Icorr) and the linear polarization resistance(Rp) were calculated by the curve-fitting method.These parameters were subjected to the verification of actual leaching process of a refractory gold ore.The results showed that the gold corrosion rate first increased and then decreased with the augment of sodium hypochlorite concentrations.The gold anode started to passivate at the concentration of 0.75 mol/L.The outcomes of the actual leaching experiments were in good agreement with the electrochemical profile.The corrosion of gold accelerated with the increase of pH values,resulting in an increase of the leaching rate.However,the leaching rate would decreased slightly after the pH value exceeded 12,which is slightly different from the results of the electrochemical studies.
引文
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[2]BAGHALHA M.Leaching of an oxide gold ore with chloride/hypochlorite solutions[J].International journal of mineral processing,2007,82(4):178-186.
[3]金创石,张廷安,牟望重,等.液氯化法浸金过程热力学[J].稀有金属,2012(1):129-134.KIM C S,ZHANG T A,MU W Z,et al.Thermodynamics of gold chlorination leaching process[J].Chinese journal of rare metals,2012(1):129-134.
[4]燕璞,刘宪超,唐道文,等.用次氯酸钠从卡淋型金矿石中浸出金的热力学[J].湿法冶金,2016,147(3):196.YAN P,LIU X C,TANG D W,et al.Thermodynamics on leaching of gold from carlin type gold ore using sodium hypochlorete[J].Hydrometallurgy of China,2016,147(3):196.
[5]巩海娟,李滦宁,赵淑杰,等.从氯化浸金稀溶液中提取金、银工艺研究[J].黄金,2009,30(11):38-42.GONG H J,LI L N,ZHAO S J,et al.Research on gold and silver extraction from chloride gold leaching dilute solution[J].Gold,2009,30(11):38-42.
[6]李民权,关玉蓉.氯化浸金机理研讨[J].黄金,2003,24(2):35-38.LI M Q,GUAN Y R.Study on mechanism of chlorination-leaching gold[J].Gold,2003,24(2):35-38.
[7]OFORI-SARPONG G,OSSEO-ASARE K,TIEM M.Fungal pretreatment of sulfides in refractory gold ores[J].Minerals engineering,2011,24(6):499-504.
[8]HASAB M G,RAYGAN S,RASHCHI F.Chloridehypochlorite leaching of gold from a mechanically activated refractory sulfide concentrate[J].Hydrometallurgy,2013,138(6):59-64.
[9]NAM K S,JUNG B H,AN J W,et al.Use of chloridehypochlorite leachants to recover gold from tailing[J].International journal of mineral processing,2008,86(1/4):131-140.
[10]刘宪超,蒋中刚,唐道文,等.难浸金矿石的次氯酸钠浸出试验研究[J].湿法冶金,2014,138(6):413-415.LIU X C,JIANG Z G,TANG D W,et al.Experimental study on leaching of gold from a refractory gold ore using sodium hypochlorite[J].Hydrometallurgy of China,2014,138(6):413-415.
[11]GHOBEITI H M,RASHCHI F,RAYGAN S.Comparison of cyanide and chloride-hypochlorite leaching of a ball milled refractory gold concentrate with ultra-fine particles[J].Advanced materials research,2013,829(1):869-873.
[12]杨玮,覃文庆,刘瑞强,等.高砷难处理金精矿细菌氧化-氰化浸出[J].中国有色金属学报,2011,21(5):1151.YANG W,QIN W Q,LIU R Q,et al.Extraction of Au from high arsenic refractory gold concentrate by bacterial oxidation-cyanidation[J].The Chinese journal of nonferrous metals,2011,21(5):1151.
[13]LI Q,LI D,QIAN F.Pre-oxidation of high-sulfur and high-arsenic refractory gold concentrate by ozone and ferri-c ions in acidic media[J].Hydrometallurgy,2009,97(1):61-66.
[14]金创石,张廷安,曾勇,等.液氯化法从难处理金精矿加压氧化渣中浸金的研究[J].稀有金属材料与工程,2012(S2):569-572.KIM C S,ZHANG T A,ZENG Y,et al.Study on chlorination leaching of gold from pressure oxidation residue of refractory gold concentrate[J].Rare metal materials and engineering,2012(S2):569-572.
[15]朱萍,李坤芳,周鸣,等.超声强化原位电氯化法浸取难处理金矿[J].稀有金属材料与工程,2009,275(6):1091-1095.ZHU P,LI K F,ZHOU M,et al.Study of in situ leaching gold from refractory gold ores with method of ultrasonicaided electro-chlorination[J].Rare metal materials and engineering,2009,275(6):1091-1095.
[16]黎铉海.机械活化强化含砷金精矿浸出的工艺及机理研究[D].长沙:中南大学,2002.LI X H.Study on technology and mechanism of mechanical activation enhancing leaching of gold concentrate containing arsenic[D].Changsha:Central South University,2002.