氰化尾渣还原焙烧酸浸提铁及氰化浸金新工艺

以氰化尾渣为原料,采用还原焙烧酸浸工艺对其进行处理。当还原温度为850℃、加入煤粉质量为氰化尾渣质量的13%、还原时间为100 min时,对氰化尾渣进行还原,氰化尾渣中Fe2O3转化为Fe3O4或FeO。还原后采用硫酸浸出,当硫酸浓度为50%、硫酸用量系数为1.2、反应温度为105℃、反应时间为3 h时,铁的浸出率达到93.66%。还原焙烧渣在600℃氧化焙烧2 h经过脱碳后氰化浸金,当氰化钠用量为4 kg/t、反应时间为28 h、液固比为2:1时,金的浸出率达到92.4%。经过还原焙烧、硫酸浸出、氧化焙烧及氰化浸金,氰化尾渣渣量减少了38.8%。     

硫精矿中难选金银焙烧浸出研究

某高金硫精矿全泥氰化时金和银的浸出率低,一段焙烧预处理会造成金和银的二次包裹。实验结果显示,二段焙烧效果优于一段焙烧效果,能降低氧化铁的烧结程度,减少铁氧化物对金、银的包裹,金、银浸出率分别为79.86%、68.13%。添加剂实验结果表明,焙烧过程加入NaOH,银浸出率大幅提高;加入CaO有利于金的浸出;加入KMnO4能降低焙砂硫品位。以NaOH、CaO、KMnO4为组合焙烧添加剂,金、银浸出率提高至87.43%、85.86%。扫描电镜观察到,加入组合焙烧添加剂有利于焙砂孔隙度的提高,氰化尾渣表面腐蚀较为严重,有利于浸出剂与金、银的接触。 关健词:含金硫精矿;全泥氰化;二段焙烧;焙烧添加剂     

多硫化物微细粒浸染型金矿回收金试验研究

为回收某含碳高砷高硫微细粒复杂难处金矿中的金,分别开展了全泥氰化浸出、浮选、焙烧、酸浸试验研究。结果表明,采用常规的全泥氰化浸出和浮选工艺,对金的回收效果均不好。采用“焙烧-全泥氰化浸出”工艺,受矿石焙烧后新产生的金属氧化物包裹金的影响,金浸出率仅有72.25%。经研究发现,采用酸溶方法,对焙砂进行加温酸浸预处理,可有效打开其被包裹的金,从而提高对金的回收。采用矿石“焙烧-酸浸-水洗-碱浸-全泥氰化浸出”联合工艺,金浸出率88.52%。     

氰化尾渣硫酸熟化焙烧中铁物相变化

利用热重分析仪、X射线衍射仪、扫描电镜分析了高砷高硫难处理金矿二次焙砂氰化尾渣硫酸熟化焙烧中铁物相变化及其终始状态矿物学特征。得出铁物相转变过程为:Fe2O3→HFe(SO4)2·4H2O→Fe2(SO4)3·5H2O→Fe2(SO4)3→Fe2O3。扫描电镜分析结果显示,硫酸熟化焙烧破坏了原有矿物有序结构,打开了包裹金的氧化铁,从而提高金的氰化浸出率。     

焙烧氰化尾渣中金、银和铁的回收利用研究进展

焙烧氰化尾渣是黄金生产排放的一类危险固体废物,其中的金、银和铁等有价金属元素仍可作为二次资源利用。系统总结了国内外在回收焙烧氰化尾渣中金、银和铁的研究进展,分析了磁化焙烧法、硫脲浸出法、氯化浸出法、高温氯化焙烧法、强酸预浸-氰化浸出法、直接还原焙烧法和细磨法在资源综合回收利用中的优缺点,指出焙烧氰化尾渣的资源化、减量化和无害化的发展方向。     

高硫砷金矿焙砂的硫酸熟化法预处理

基于氧化铁与硫酸反应的热力学原理,采用硫酸熟化-水浸法对高硫高砷金精矿氧化焙砂进行预处理,以脱除铁氧化物,破坏其对金的包裹,提高金浸出率。结果表明,在适宜的硫酸含量下,赤铁矿与硫酸反应的产物硫酸铁可转化为板铁矾HFe(SO4)2·4H2O晶体,降低了产物浓度,从而使赤铁矿继续溶解,提高了铁脱除率;适当升高温度可促进扩散的进行,从而使铁的脱除更加彻底。焙砂的氰化浸金率在脱除铁氧化物后显著提高。对于某铁含量为31.25%(质量分数)金含量为84.27 g/t的焙砂,当熟化条件为硫酸含量75%、硫酸过剩系数1.4、熟化温度250℃、熟化时间1 h时,焙砂中残余铁含量降至7.23%,此时金浸出率可达97.51%。     

磁化焙烧对氰化尾渣中金、铁回收的影响(英文)EI北大核心CSCD

对氰化尾渣的焙烧预处理及其对有价金属综合回收的影响进行了研究。结果表明:当焙烧温度为750℃、焙烧时间为1.25h、还原剂添加量为6%时,铁的磁化率为86.27%,金的浸出率达到46.14%。结合矿物构造与赤铁矿磁化焙烧原理,探讨了焙烧对金浸出影响的机理,认为赤铁矿磁化焙烧后解离出的包裹金,是提高金浸出率的主要来源。     

氰化尾渣中金铁梯级提取及铁精粉中杂质形成机理

采用"磁化焙烧-硫脲浸金-磁选-碱浸除杂"的金铁梯级提取法从焙烧氰化尾渣中浸出金,并制取铁精粉,通过物相转化、焙烧过程热力学计算和颗粒群结构分析,揭示铁精粉中杂质形成机理。结果表明:氰化尾渣添加8%焦粉于700℃下磁化焙烧60 min,焙烧样以硫脲法浸金,金浸出率达65.87%;浸金渣经磨矿磁选得到TFe品位为55.01%的初级铁精粉,再于90℃的10%NaOH溶液中碱浸8 h,可得TFe品位为62.22%、回收率为69.80%的合格铁精粉。物相转化和热力学计算表明,磁化焙烧过程中含铁矿物与Si、Ca、Al及重金属等杂质反应,生成铁橄榄石、钙铝榴石和铁钙辉石等新物相,与磁铁矿紧密共生,混入铁精粉中;微细粒磁铁矿存在严重磁团聚,石英等杂质会机械夹杂在磁团聚中,降低铁精粉质量。     

难浸金矿石的预处理法

用硫脲法和传统的氰化法处理含砷为9．09％、硫13．07％、金12．25g／t的难浸金矿石,其浸取率分别为72．38％和21．22％。采用氧化焙烧对该矿石进行预处理,可提高其浸取率,在氰化浸出和硫脲浸出中浸取率分别可达80．63％和89．80％。在硫脲浸出中,只需加少量的预处理剂,浸取率即可达90％以上。     

复杂金精矿铁锍酸溶渣控电位氯化浸出富集贵金属金

以复杂难处理金精矿火法造锍捕金所得铁锍合金的硫酸浸出渣为原料,采用控电位氯化浸出工艺分离酸溶渣中的Cu、As、Sb等主要杂质元素,贵金属Au单向富集得到高品位金泥,Au泥经过硫酸化焙烧脱硫进一步富集贵金属金。结果表明:双电极体系控电位氯化浸出优化条件为[H~+]5mol/L、浸出电位380m V、液固质量比5:1、温度85℃和搅拌浸出2 h,所得渣率为28.2%,浸出渣中Cu、As、Sb含量分别降到0.18%、0.095%、0.084%,浸出率分别达到99.6%、99.8%、99.8%,浸出渣主要成分Si和S的含量分别为29.39%和22.72%,Au品位富集到2.609%;浸出渣硫酸化焙烧脱硫的烧成率为66.5%,S含量降至0.87%,脱硫率为96.2%,焙砂的主要物相为SiO_2和单质金,Au品位富集到3.937%。复杂金精矿铁锍合金酸溶渣通过控电位氯化浸出除杂—焙烧脱硫可将贵金属金有效富集。     

High-temperature chlorination of gold with transformation of iron phase

Gold in cyanide tailings from Shandong Province is mainly encapsulated by hematite and magnetite at distribution rates of 76.49 % and 10.88 %, respectively.Chlorination–reduction one-step roasting of cyanide tailings was conducted under the following conditions: calcium chloride dosage of 6 %, bituminous coal dosage of30 %, calcium oxide dosage of 10 %(all dosages are vs.the mass of cyanide tailings) at 1000 °C of roasting temperature. X-ray diffraction(XRD), scanning electron microscopy(SEM), and chemical-phase analysis were performed to investigate the effects of iron phase transformation on the high-temperature chlorination of gold.Results indicate that the lattice structure of hematite undergoes expansion, pulverization, and reorganization when hematite is reduced to magnetite, which leads to42.03 % gold exposure, and the high-temperature chlorination rate of gold is 41.17 % at the same time. The structure of wustite formed by the reduction in magnetite is porous and loose, and thus 44.02 % of gold is exposed. The high-temperature chlorination rate of gold is increased by41.98 percentage points. When wustite is reduced to metallic iron, 4.42 % of gold is exposed, and the hightemperature chlorination rate of gold is increased by3.38 percentage points. Accordingly, the high-temperature chlorination of gold mainly occurs in two stages, in which Fe_2O_3 is reduced to Fe_3O_4, and Fe_3O_4 is reduced to Fe_xO finally.     

草酸配位浸出二段焙砂中包裹金的赤铁矿

草酸根(ox^2-)对三价铁具有强的配位能力,可用草酸配位浸出二段焙砂中包裹金的赤铁矿,提高金的回收率。考察了草酸用量、液固比、浸出温度和时间对二段焙砂中铁浸出率的影响。结果表明,用1.17倍理论量的草酸在液固比为12 mL/g时于90℃浸出2 h,铁浸出率达到75.8%以上。除铁渣进一步氰化浸出,渣中金品位为8.8 g/t,低于直接氰化浸出渣12.3 g/t的金品位。草酸浸出液主要成分为具有光催化活性的Fe(ox)⁺和Fe(ox)2^-,可采用光催化法回收铁、再生草酸,再生的草酸可返回浸铁过程。     

国内氰化法浸出金矿中金的研究进展

基于中国期刊全文数据库(CNKI),检索了2014~2018年氰化法浸出金矿中金的论文和专利,对国内相关研究进行综述讨论。文献分析表明,对贫金矿的开发是近年来研究的热点,有关氰化工艺、氰化条件、尾渣处理和贫液净化的研究较多,但氰化浸出条件之间的交互影响,以及脉石矿物对氰化浸出效率影响的相关研究较少。建议通过工艺完善、加强应用软件模拟等研究,不断完善金矿氰化浸出理论与实践,提高金矿资源的利用率。     

Use of ferricyanide for gold and silver cyanidation

Low gold and silver leaching kinetics has been commonly observed in traditional gold-silver cyanidation process, especially in heap leaching and in situ leaching operations. The different mineralogy of gold and silver in the ores is suspected to be the main reason, e.g., the occurrence of low solubility acanthite (Ag2S) typically results in low overall silver extraction. Due to the low solubility of oxygen in cyanide solution, the reactivity and availability of oxidant is believed to be the critical limitation for gold and silver dissolution. The use of ferricyanide as the auxiliary oxidant for gold and silver cyanidation has been examined. The rotating disc test results prove the assistant effect of ferricyanide on increasing the dissolution rate of gold and silver. The potential use of ferricyanide in gold/silver cyanidation process is proposed based on the leaching results of actual ores.     

重金属强化含金矿石的氰化浸出

通过分析铊、铋、汞和铅等重金属强化金氰化溶解的电化学原理,对含金氧化物矿石和难浸硫化物金精矿进行了重金属强化浸金研究.结果表明:重金属对金氰化溶解的阳极过程有显著的强化作用,但在常规供氧条件下,金的溶解速率并未显著提高;只有同时采用阴极强化措施,才能使重金属起到显著提高金溶解速率的作用;对于含金氧化物矿石,单独采用重金属强化即可明显提高浸金速率,如果在过氧化氢助浸的基础上添加重金属,金的浸出速率会有更大幅度的提高;对硫化物金精矿而言,单独采用重金属无明显强化效果,只有在添加过氧化氢作为辅助氧化剂的基础上,重金属对金的浸出才能起到强化的作用,该体系中过氧化氢起到了强化阴极过程和氧化硫化物的双重作用.     

Simultaneous extraction of gold and zinc from refractory carbonaceous gold ore by chlorination roasting process

A novel process based on chlorination roasting was proposed to simultaneously recover gold and zinc from refractory carbonaceous gold ore by using NaCl as chlorination agent. The effects of roasting temperature, roasting time and NaCl content on the volatilization rates of gold and zinc were investigated. The reaction mechanism and the phase transition process were also analyzed by means of SEM, EDS and XRD. The results demonstrated that under the optimal conditions of NaCl content of 10%, roasting temperature of 800 °C, roasting time of 4 h and gas flow rate of 1 L/min, the rates of gold and zinc were 92% and 92.56%, respectively. During low-temperature chlorination roasting stage, a certain content of sulfur was beneficial to the chlorination reactions of gold and zinc; and during high-temperature chlorination roasting stage, the crystal structure of vanadium-bearing mica was destroyed, and the vanadium-containing oxides were beneficial to the chlorinating volatilization of gold and zinc. Eventually, the chlorinated volatiles of gold and zinc could be recovered by alkaline solution.     

Increasing leaching rate of gold cyanide of two-stage calcination generated from refractory ore containing arsenopyrite and pyrrhotite

For the gold locked within hematite in the two-stage calcination, which leads to a low gold leaching rate, the present work is aiming at pretreating the calcination to selectively dissolve hematite. The calcination was pretreated by sulfuric acid with cosolvent B. The factors influencing the hematite dissolution rate were studied, and the pretreatment parameters considered were H₂SO₄ content, B dosage and added time, leaching temperature and time. Simultaneously, mineralogy analysis of the calcination, H₂SO₄ pretreatment residue and cyanide leaching residue were also carried out. Results indicate that the hematite dissolution rate is quicker, the dissolution temperature is lower and the dissolution time is shorter in the role of cosolvent B than without B. At the same time, the gold locked within hematite is effectively released, so the leaching rate of gold cyanide increases about 10 % than that in actual factory production. The results have an actual significance in guiding industrial production.