氧压渣非氰体系浸金及其机理

以氧压渣为原料,考察酸性硫脲体系和碱性多硫化物体系碳浸法浸金效果,对浸出过程矿相行为进行分析。结果表明:碱性多硫化物体系较酸性硫脲体系金浸出率高30%,碱性多硫化物体系包裹金得到释放和暴露,利于金的高效浸出。在碱性多硫化物体系下考察各因素对金浸出率的影响并确定最优浸出条件,在最优条件下,金的浸出率达85%以上。开展深度浸金研究,超声波强化金浸出率达89.77%,超细磨金浸出率达91.95%。     

硫脲-硫氰酸钠浸出难处理金矿及浸出剂的稳定性

采用高温焙烧、硫脲-硫氰酸钠浸出难处理金矿中的金,研究焙烧温度、硫氰酸钠浓度、硫脲(Tu)浓度、Fe3+浓度、pH值、浸出温度和时间对金浸出率的影响,得到混合体系浸金的最优条件,并研究浸出过程中硫氰酸钠和硫脲的稳定性。结果表明:金的浸出率达到93.1%,超过相同条件下单一体系中的浸出率之和,硫脲与硫氰酸钠摩尔比对金浸出率和金电极稳定电位影响较大;硫氰酸钠使硫脲的稳定性降低,而硫脲使硫氰酸钠的稳定性增强。     

从废弃印刷线路板中回收金的试验

试验研究了采用硫脲法有效地从废弃印刷线路板中回收金.试验结果表明,硫脲回收金的主要影响因素有温度、硫脲质量浓度、Fe3+质量分数、浸出时间、硫酸体积分数;合适的浸出条件是固液比为15,浸出温度为35℃,硫脲质量浓度为10g/l,Fe3+质量分数为0.3%,浸出时间为1h,硫酸体积分数为5%.     

硫脲浸金电化学行为研究

采用循环伏安法(CV)、Tafel曲线和差分脉冲伏安法(DPV)等电化学方法对模拟硫脲浸金体系进行了研究.结果表明,硫脲浓度范围为0.005～0.04 mol/L,浓度增大有利于金的浸出;在Fe3+浓度为0.01～0.08 mol/L范围内,随着Fe3+浓度的增大,金腐蚀电位负移,腐蚀电流变大;适度升温可以提高金的腐蚀...     

液氯化法从难处理金精矿加压氧化渣中浸金的研究

针对国内某难处理金精矿的加压氧化渣进行液氯化法浸金的热力学计算及浸出单因素实验,考察pH值、氯化钠浓度、反应温度及反应时间等因素对浸金率的影响。结果表明,金氯化浸出反应的热力学条件为:pH值小于8、电位大于0.9V;液氯化法浸金最佳实验条件为:pH值4、电位1.0V以上、氯化钠浓度75g/L、反应温度40℃、液固比3:1、搅拌速度300r/min、反应时间120min,浸金率为96.54%。此方法显著地提高浸金率,并且具有试剂消耗少、污染少、反应速度快等优点。     

预浸-氰化浸出回收湿法炼锌渣中的银和金

某冶炼厂的锌浸出渣中银勘布粒度细,含银、金分别为381.3、1.02 g/t,可采用预浸-预浸渣氰化浸出工艺回收。重点研究了预浸条件对银、金浸出效率的影响。条件实验表明,药剂A比酸浸、氨浸具有更好的预浸效果;最佳预浸条件为药剂A浓度200 g/L、浸出液固比2:1、在50℃浸出3 h。综合条件实验得到的预浸渣渣率为66.2%,金、银的氰化浸出回收率分别为85.7%、92.9%。     

难冶金精矿烟尘中铁砷碳的脱除对氰化浸金的影响

以难冶金精矿烟尘为原料,研究了氢氧化钠浸出、硫酸浸出以及硫酸与氢氧化钠联合浸出对烟尘中砷、铁和碳脱除及氰化浸金的影响。结果表明:在氢氧化钠浓度为6mol/L时,砷、碳脱除率分别为99.66%和60.63%,金浸出率为58.90%,较直接氰化浸出仅提高4.60%,砷的有效去除不能有效提高金的浸出率。在硫酸质量分数为15%时,铁、砷和碳脱除率分别为33.65%、80.38%和12.59%,金的浸出率为80.40%,与氢氧化钠浸出相比,硫酸浸出解离铁能有效提高金的浸出率。烟尘分别经过质量分数为15%硫酸浸出后氰化浸金,两次2 mol/L氢氧化钠浸出和氰化浸金后,烟尘中铁、砷和碳的总脱除率分别为33.65%、95.63%和79.60%,渣率为80.33%。此时,金的总浸出率为91.90%,氰化渣中金的含量为3.31g/t。与烟尘直接氰化浸出相比金的浸出率提高37.60%。     

基于配位理论的碱性硫脲选择性溶金机理

采用电化学方法研究了金及常见伴生金属元素银、铜、镍、铁在高稳定性碱性溶液中阳极溶解的电化学行为,及碱性硫脲浸金的选择性.结果表明:在最佳溶金电势0.42 V时,金在碱性硫脲溶液的溶解电流密度分别是银、铜、镍和铁的3.4,5.2,27.3和42.6倍;而且碱性硫脲体系进行矿物浸出时金的伴生元素浸出率均小于0.1%,浸金具有显著的选择性.采用配合物的化学键理论、配位理论等分析了碱性硫脲选择性溶金的机理.碱性硫脲溶液中金、银、铜、镍和铁分别以Au(TU) 2,Ag(TU) 3,Cu(TU)2 4,Ni(TU)2 4和Fe(TU)2 6的形式存在,Au(TU) 2中反馈σ-π配键的形成显著增强了其稳定性.配合物Ni(TU)2 4和Fe(TU)2 6中,由于硫脲分子的特殊性,各配位体间硫原子和氮原子上电子云互相排斥,使其稳定性有所降低.而且碱性硫脲溶液中,Ag,Cu,Ni,Fe易于形成致密的硫化物钝化膜,在一定程度上也阻碍了金属的进一步溶解.     

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。     

一种新的添加剂(Re-1)在硫脲浸金中的应用

报道了一种用于硫脲法浸金过程的新的Re－1型溶金添加剂,实验证实该添加剂可以改善硫脲浸金液状态,降低浸液硫脲浓度,提高金出率。可使含砷硫化原生矿的一次金浸出率达到89％以上。同时,测定了工艺的最佳条件并讨论了Re－1添加剂对浸金机理的影响。     

Characterization of refractory behaviour of complex gold/silver ore by diagnostic leaching

The amenability of a refractory ore to the extraction of gold and silver by cyanide leaching was investigated. Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ≤47% and ≤19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. ＜38 μm) does not improve the recovery of gold and silver. Diagnostic leaching approach provides information into the cause of the refractoriness of the ore. The findings suggest that the refractoriness is induced by the dissemination and encapsulation of the very fine gold and silver particles largely in the carbonates, oxides and sulfides and, to a small extent, with silicates present in the ore matrix. These findings highlight the practical importance of diagnostic leaching for the understanding of the refractory characteristic of such an ore and for the identification of possible pretreatment options to overcome its refractoriness prior to cyanide leaching.     

LEACHING OF PRECIOUS METALS FROM COMPLEX SULPHIDE ORES——2.DIRECT LEACHING OF Cu SULFIDE CONCENTRATE BY ACIDIC THIOUREA SOLUTIONS

Recovery of gold and silver from a sulphide concentrate by thiourea leaching was investigat-ed.The effects of various parameters on the process,such as oxidants,the initial concentrationof thiourea and acidity in solutions as well as reaction temperature,were systematically exam-ined.From the results it was confirmed that(a)oxidants had no significant influence on the dis-solution of gold and silver at a fixed initial concentration of thiourea;(b)the initial concentra-tion of thiourea and acidity affected the dissolution rate only in the earliest period of leaching;(c)the rate of the process was controlled by reagent diffusion.The optimum operations wereworked out for the thiourea leaching process of the concentrate.     

难处理金矿非氰提金方法研究现状

简要叙述了难处理金矿资源现状,分别介绍了硫脲法、硫代硫酸盐法、卤素法、石硫合剂法等非氰提金方法的浸出机理及国内外最新研究状况,综合比较各种方法的优缺点,最后指出其今后发展方向。     

焙烧氰化尾渣提金工艺研究现状

焙烧氧化过程中铁物相出现熔融或再结晶,对金造成二次包裹,使焙砂中部分金仍难以浸出,导致焙烧氰化尾渣金品位较高。破坏尾渣中铁氧化物对金的包裹可提高金的浸出率。综述了焙烧氰化尾渣主要提金工艺,包括直接酸溶法、还原焙烧法、氯化法、炼铁-电解法、硫酸熟化法和硫脲法等。直接酸溶工艺简单,金浸出效果较差;还原焙烧法金浸出率高,但工艺复杂、能耗大;氯化焙烧法对矿石适应性强,可综合回收有价金属,但基建及维护费用高;炼铁-电解法在富集金的同时可获得纯铁产品,对矿石有较高的要求;硫酸熟化法显著提高金银浸出率,与直接酸溶法相比,所需更高的温度与酸度;硫脲法反应速率快、选择性好,但生产成本较高。 关健词:有色金属冶金;氰化尾渣;铁氧化物;包裹金;提金     

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。     

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.     

碱性硫脲浸金的研究现状与发展趋势

阐述了可能取代氰化浸金的高效、无毒碱性硫脲浸金的研究现状。相比酸性硫脲浸金,碱性硫脲浸金具有溶金选择性好,溶液的再生及净化工序相对容易等优点。阐明了碱性硫脲浸金原理及金在碱性硫脲溶液中的溶解机理,对碱性硫脲溶液中的稳定剂及氧化剂的选择做了详细探讨。最后,指明了碱性硫脲浸金所取得的成果及需要解决的问题,并展望了其发展趋势。     

从废弃印刷线路板中回收金的试验

试验研究了采用硫脲法有效地从废弃印刷线路板中回收金。试验结果表明，硫脲回收金的主要影响因素有：温度、硫脲质量浓度、Fe^3＋质量分数、浸出时间、硫酸体积分数；合适的浸出条件是：固液比为1：5，浸出温度为35℃，硫脲质量浓度为10g／l，Fe^3＋抖质量分数为0．3％，浸出时间为1h，硫酸体积分数为5％。     

Alkaline sulfide pretreatment of an antimonial refractory Au-Ag ore for improved cyanidation

This paper presents the alkaline sulfide pretreatment of an antimonial refractory gold and silver ore. In the ore, gold occurs mainly as gold-silver alloys and as associated with quartz and framboidal pyrite grains, and, to a small extent, as the inclusions within antimonial sulfides. Silver is present extensively as antimonial sulfides such as andorite. Alkaline sulfide pretreatment was shown to allow the decomposition of the antimonial sulfide minerals (up to 98% Sb removal) and to remarkably improve the amenability of gold (e.g., from <49% up to 83%) and silver (e.g., from <18% up to 90%) to subsequent cyanide leaching. An increase in reagent concentration (1–4 mol/L Na₂S or NaOH) and temperature (20–80°C), and a decrease in particle size seem to produce an enhancing effect on metal extraction. These findings suggest that alkaline sulfide leaching can be suitably used as a chemical pretreatment method prior to the conventional cyanidation for antimonial refractory gold and silver ores.