生物制剂浸金试验研究

生物制剂浸金试验结果表明，生物浸金制剂对氧化型金矿金的浸出率大于９５％，对经过细菌预氧化的难浸金精矿金的浸出度与氰化法相同。     

肃北县黑刺沟金矿含砷难选金矿石综合选矿试验研究

肃北县黑刺沟金矿属砾岩型金矿,该矿矿石属典型的含砷、硫微细粒难选金矿石。通过各种选矿试验,该矿矿石用全泥氰化法金浸出率低于１７％ ,浮选、焙烧氰化法浸出效果也不好,而用细菌预氧化、碱浸预氧化氰化法效果较好,金浸出率最高可达９２．４％ ,是处理该类矿石较有效的选矿方法。     

我国难浸金矿提金技术又有进展

（1）利用河南盐矿测试中心研究的难浸高硫金精矿细菌预氧化提金半工业性试验技术，对小秦岭地区潭头的难浸金精矿进行试验，经细菌预氧化6天，再氰化浸出，金浸化率达91．31％。 （2）利用西安综合岩矿测试中心研究的难浸高砷硫化金精矿细菌预氧化技术，完成了广西贵港福六金矿浮选金精矿日处理6吨和青海五龙沟金矿浮选金精矿日处理12吨以及两种混合金精矿日处理10．5吨的工业性试生产，处理量分别为400吨和200吨，金的浸出率90％～94％，生物预氧化时间150小时，处理成本为每吨600元。 （3）成都综合岩矿测试中心针对四川高硫高碳型金矿进…     

难浸金矿石的提金技术简介（一）：—难浸金矿石的氧化预处理

难浸金矿石,又称难选冶金矿石,难处理金矿石等。一般指矿石经细磨后仍有相当一部分金不能用常规氰化法有效浸出的金矿石。这类金矿石中的金,或物理包裹,或是化合结合,使之不能与氰化液接触,因而很难浸出。难浸金矿石分为三种类型:(1)非硫化物脉石包裹金,这类矿石中金粒太小,无法用磨矿解高,金粒很难接触氰化液;(2)金被包裹在黄铁矿和砷黄铁矿等硫化矿物中,细磨亦不能使包裹金粒接触浸出液;(3)碳质金矿石,金浸出时,金氰络合和被矿     

河北某氧化石英脉型金矿石全泥氰化浸出试验研究

河北省某金矿为氧化石英脉型金矿石,矿石中的金粒微细,平均粒径为0.011 3mm,包裹于黄铁矿、褐铁矿、石英中的金占64.68%,有一部分呈微细粒包裹在土状褐铁矿中,对这种细粒分散的含金氧化矿石采用全泥氰化浸金工艺。将原矿磨矿细度确定为-200目含量占85%,加入石灰对金矿石进行碱预处理,再加入氰化钠浸金,取得了浸出率为96.89%,吸附率为99.55%的试验结果。     

云南者桑金矿矿石特征和金赋存状态研究

云南者桑金矿区位于我国"滇黔桂"金三角卡林型金矿分布区,属微细浸染型金矿。通过对矿石特征和金赋存状态研究,金主要以显微、超显微自然金形式赋存于黄铁矿、毒砂等金属硫化物或其氧化物中,其次是分布在硅酸盐、碳酸盐等脉石矿物中。硫化矿石中硫化物含金量应占金总量的50%以上,部分金赋存在绢云母、脉石英及碳酸盐等脉石矿物中,含量占20%±,硅酸盐矿物中包裹金含量占20%±,极少部分金以游离金形式存在,含量占总金的10%以内;若为氧化矿则金主要为游离态金,应占总金50%以上,赋存于炭质和粘土矿物中。     

甘肃礼县上坝金矿金的嵌布特征和赋存状态研究

通过对甘肃礼县上坝金矿工艺矿物学研究,查明了矿石中的矿物成分,金的赋存状态以及影响金回收的矿物学因素,研究证明金的嵌布主要与石英、褐铁矿有关。矿石氧化率高,金的粒度普遍细小,金矿物嵌布分散,该成果对湿法浸金技术具有指导作用。     

甘肃全鑫金矿矿石难浸原因初探

全鑫金矿为变质碎屑岩型金矿床,矿化类型可分为含金石英脉和破碎蚀变岩型。通过对矿石的工艺矿物学性质的研究,矿石的Au含量一般在1×10-6～4×10-6之间,并含有C有机,As,属C As型金矿石。矿石中金属矿物主要为褐铁矿、赤铁矿及黄钾铁钒,金矿物以含银自然金为主,自然金与褐铁矿关系十分密切,常以包裹体形式嵌布于其中,粒度一般为0 002mm左右。筛分后,不同粒级矿样的Au含量不同,在小于0 037mm粒级中,Au含量达4 72×10-6,分布率高达93 42%。经过小型工业堆浸试验,呈现出周期较长、浸出率较低的特征。其原因是金的单体解离和暴露不充分,浸矿液中的氰化物难以与所有的金粒发生作用。同时,矿石中石墨、C有机及其他一些粘土矿物也促使含Au溶液中的Au发生沉淀,造成浸出率降低。     

东大滩锑金矿微生物预氧化提金试验研究

介绍了东大滩难浸金矿石微生物预氧化的方法及结果。东大滩石英脉型锑金矿石因金被毒砂包裹而难浸，采用微生物预氧化处理后全泥氰化金的浸出率由原来的17．04％提高到70．80％，柱浸由15．39％提高到63．02％，且酸耗较低，各项指标合理，是解决该类矿石难浸的理想方法。     

石棉地区难处理金矿石浸金工艺初步研究

含有机碳、粘土物质、砷、铜较高的难处理原生硫化金矿石广泛分布于石棉西部地区。多年来该区该类型金矿的选矿一直采用混汞法收金或原矿浮选、产品销售冶炼厂的办法。本文根据矿石特性选择原矿氢氧化钠碱浸预处理→次氯酸钙氧化处理→氰化提金工艺进行探索性试验，获得金浸出率86．9％的结果，为石棉地区该类型金矿石的开发利用开辟了一条新的途径。     

卡林型金矿石中金的赋存状态分析新方法

卡林型金矿富含有机质,金主要呈显微一超显微分散状态存在,利用工艺矿物学参数自动检测分析仪(MLA)及传统化学方法只能大致判断矿石中金的赋存趋势,无法对其赋存状态准确定量.本文利用MLA仪器系统分析贵州回龙卡林型金矿,测得矿石中金主要以显微-超显微状态包裹于黄铁矿和毒砂中,少量被脉石等其他矿石包裹;黄铁矿约66％完全解离,而毒砂仅30％完全解离,载金矿物与其他矿物连生或者被包裹,将不利于硫化物包裹金的浸出.结合回龙金矿石中金的赋存特征和富含有机质的特点,对传统的物相分析流程进行改进,调整了硫化物包裹金和碳酸盐包裹金的浸出顺序,提出裸露金-碳酸盐包裹金-硫化物包裹金-硅酸盐包裹金的浸出流程,在裸露金及碳酸盐包裹金浸出时加入活性炭,利用竞争吸附抑制矿石中有机炭对金的吸附,降低有机炭对分相的影响.对比试验结果表明,采用改进的方法,有机炭含量在1％左右的金矿石分相时加入活性炭对各相测定值的影响不大;先浸出碳酸盐包裹金,再测定硫化物包裹金,各相的测定数据更加准确.改进的方法(加活性炭)用于测定回龙金矿中裸露金和碳酸盐、硫化物、硅酸盐包裹金,含量分别为1.25％、84.17％、11.46％和3.13％,与选矿试验结果相一致,表明该法适合应用于卡林型金矿中金的赋存状态分析.     

金矿的细菌浸出处理研究

利用细菌对难处理金矿进行浸出处理,具有成本低廉、环境污染小、处理效率高等突出优点,已成为非常有前途的难处理金矿的预处理方法。笔者以河北遵化滑石峪金矿(含金黄铁矿)样品为例,在几种氧化亚铁硫杆菌中发现D3菌种处理此类难浸金矿有显著的增大提金率的效果。在200目粒度条件下,氰化提金率从单纯氰化的63.9%提高到细菌预处理后再氰化的88.2%,而且对100目以下的大粒度金矿,提金率也普遍提高10%以上;此外,还进行了该菌种处理金矿过程的条件实验,如粒度影响、pH值变化和物理方法强化的研究,得出了金矿在细菌氧化过程中的一些规律和在实际操作时的最优化控制条件。     

松潘两岔河高砷高锑金矿石氰化提金工业试验

高砷高锑金矿石属难处理矿石之一，通过对两岔河高砷高锑金矿石采用碱浸预处理后进行堆浸和池浸氰化提金试验，获得了金浸出率76．80％和86．76％的较好指标，为该矿床的开发利用提供了一个工艺简单、经济上可行的途径。     

Gold in Egypt: Does the future get worse or better?

Within the Eastern Desert of Egypt, there are more than a hundred vein-type gold deposits and occurrences. Gold was mined in the Dynastic and Roman periods of the Egyptian history and most of the attention was focused entirely on the near-surface high grade parts of these veins. Currently, besides the more problematic sulfide-rich quartz veins, which generally occur in the lower levels of the worked out auriferous quartz veins, some targets including wall-rock alteration, listwaenite, dumps and tailings of ancient mines, by-product gold hosted in volcanogenic massive sulfide deposits and gold-bearing Algoma-type BIF, as well as alluvial gold constitute the new targets for gold in the Eastern Desert of Egypt. In most of these targets, gold displays a bimodal distribution; occurring both as free-milling gold and in the form of sub-microscopic or “invisible” gold in refractory sulfides and sulfoarsenides such as pyrite, chalcopyrite, arsenopyrite, gersdorffite and pentlandite minerals.Characterizing gold in an ore is important in extraction metallurgy. Free-milling gold can be efficiently recovered by crushing, grinding and cyanidation without additional processing. In refractory ores, on the other hand, conventional milling can liberate the sulfides from the gangue allowing a low content of concentrate to be produced by a process such as flotation. However, direct leaching of the concentrate results in poor gold extractions as the cyanide lixiviant is unable to contact the gold locked within the refractory host. Oxidative pretreatment is required for such ores and the methods available for oxidation are roasting (calcination), pressure oxidation, and bacterial oxidation; all oxidize the refractory minerals in the ore to render the gold amenable to cyanidation. While such oxidative methods are capable of achieving reasonable recoveries, they increase the capital and operating costs. An alternative, applicable to the liberation of gold from the refractory host, is to continue the grinding process to reduce the particle size of the host mineral thereby exposing a part of the gold surface for contact with the cyanide solution. A benefit of this technique is that the environmental aspects of the oxidation reaction products are avoided, however the ultra fine grinding also adds more operating costs.Metallurgical studies carried out on some gold deposits, dumps and tailings of ancient gold mines in Egypt, proved that these ores are amenable to percolation leaching (concentration of KCN varies between 0.5 and 1 g/L) for the (− 10 mm) grain size, and consequently heap leaching is a successful technique as the results of these laboratory scale column tests show. In most of these studies, a marked improvement in the percent of gold recovery was gained when the crushed ore is agglomerated by the addition of water, lime and/or cement particularly in ores containing significant quantities of clay minerals and clay-forming minerals (e.g. sericite and muscovite), and by addition of kerosene which passivates the adsorption surfaces on the graphite.Placer gold is recovered by gravity methods utilizing the large difference in specific gravity between gold and commonly associated minerals such as quartz and feldspar. The equipments range from a simple pan to more complex devices used in gold recovery plants and dredges.Modern studies in Egypt point to the presence of different targets of gold; diverse in their gold content, mode of occurrence of gold and the metallurgical treatments required for extracting gold. With the advance of modern techniques such as Electron Microprobe Analyses (EMPA), laser Ablation Microprobe Inductively Coupled Plasma Mass Spectroscopy (LAM-ICP-MS), gold ores in Egypt should be re-characterized precisely to know the specifications of these ores and consequently predict the metallurgical regime required, and with the high world gold price, it has become necessary to take into consideration the presence of refractory gold ores as one of these targets in Egypt. Generally speaking, laboratory experiments conducted on gold processing in Egypt are encouraging to some extent; however the gold extraction rates of the free milling ores with conventional cyanidation and refractory ores with direct and pretreatment techniques can be improved by modifying the conditions of extraction to be consistent with the results obtained from the re-characterization stage. Otherwise any target for gold and whatsoever the mode of occurrence of gold in this target (i.e. free-milling and/or refractory) could be recovered directly by heap leaching technique and we should accept less than ideal gold recovery for any target when weighed against the capital expenditure required for processes such as roasting, and the continuous grinding processes which might improve recoveries by only a small percentage.     

Preliminary analysis on roles of metal–organic compounds in the formation of invisible gold

The paper comprises new analytical data on the nature and occurrence of gold in solid pyrobitumen, closely associated with the main gold-bearing sulfide arsenic ores of the Bakyrchik gold deposit (Kazakhstan), related to post-collisional magmatic-hydrothermal origin. Gold mineralization of the deposit occurs mainly in the form of an “invisible” type of gold in the structures of arsenian pyrite and arsenopyrite, and the form of gold-organic compounds of pyrobitumen in carbonaceous-terrigenous sequences of Carboniferous formation. Microscopic and electron microscopic analysis, Raman and FT-Infrared analysis, mineralogical and three-step sequential extraction analysis (NH₂OH·HCl, H₂O_2, HNO₃ + HCl) has been carried out using 9 ore samples (from 3 different types of ores) for a comprehensive study of pyrobitumen and sulfide arsenic ores focusing mainly on organic matter. The sequentially extracted precious metal content of pyrobitumen reaches up to 7 ppm gold and other metals like Ag 4 ppm, Pt 31 ppb, and Pd 26 ppb, forming metal–organic compounds, while arsenic sulfide minerals incorporate 11 ppm gold, 39 ppm Ag, 0.49 ppm Pt. The enrichment of gold associating with organic matter and sulfide ore minerals was confirmed in this study. Organic matter was active in the migration of gold and the capture of gold by pyrobitumen. Moreover, the reductive organic matter agent released gold, most likely for the sulfide arsenic ore minerals. Pyrobitumen was a decisive factor in the concentration, transportation, and preservation of gold in the deposit.

     

Analysis of the gold recovery profile through a cyanidation plant

Leaching in the grinding circuit is currently practiced in plants that process gold ores with low content of cyanide consuming minerals. The high gold recovery observed in the grinding–classification section of the plant is commonly explained by the inherent high initial dissolution rate of gold observed in gold ore cyanidation, or by the intense agitation prevailing in grinding mills. For understanding this leaching behavior of gold ores, the grinding, classification and leaching sections of a gold processing plant are analyzed through reconciliation of operating data. It is found that gold circulation in the grinding circuit is quite different from the flow behavior of other species due to the strong gold separation effect in the hydrocyclones, which produces quite large residence time for gold-rich particles. The results presented in this study demonstrate that the residence time of these particles in the grinding circuit can be as long as in the leaching tanks and might be the dominant factor in explaining the high dissolution of gold in this section.     

秦岭卡林型金矿床金、砷地球化学探讨

讨论了秦岭卡林型金矿床中Ａｕ 、Ａｓ 的元素地球化学、矿物学特征。在含矿岩系中获得的Ａｕ、Ａｓ 等成矿元素初始含量较高,且主要集中在成岩黄铁矿中。在矿石样品中对含砷硫化物矿物的研究表明,Ａｕ 、Ａｓ 在矿物显微结构中具有强的正相关性。在大量金进入到硫化物结构之前,就已有［ＡｓＳ］３ － 的存在。在含砷硫化物矿物中,金多半以一种带电类型（Ａｕ３ ＋） 存在, 它很可能替代铁位置上的过剩砷, 以固溶体方式沉淀于硫化物矿物中。此时, 黄铁矿构成（Ａｕ３ ＋ ,Ｆｅ２ ＋）（［ＡｓＳ］３ － ［Ｓ２］２ － ）,毒砂构成（Ａｕ３ ＋ ,Ｆｅ２ ＋）（［ＡｓＳ］３ － ［ＡｓＳ］３ －） 。通过电子探针（ＥＭＰ） 和透射电镜（ＴＥＭ） 对秦岭卡林型金矿含砷硫化物矿物中金的赋存状态的研究表明,在金的成矿作用早期阶段, 金主要以固溶体形式优先富集于含砷黄铁矿和毒砂及砷黝铜矿之中,并且认为是以金的氧化和砷的还原的共沉淀方式发生的。在此之后的金成矿作用晚期阶段,由于热液蚀变和结晶作用程度的增高,寄主矿物耐熔性质相对降低,加之金本身的聚集能力,和因过量砷加入而造成的含砷硫化物矿物的晶格缺陷,致使已形成的固溶体金以“出溶”形式发生再分布,赋存于硫化物矿物晶粒     

青海果洛龙洼金矿床金的赋存状态研究

果洛龙洼金矿床物质组成简单,属少硫化物型,金属矿物含量约5.4%,脉石矿物含量约94.6%.载金矿物以石英和黄铁矿为主,金矿物有银金矿和自然金,在矿石中分布很不均匀,以裂隙金和粒间金为主要赋存形式.金矿物粒度较细.     

额济纳旗老硐沟氧化-淋滤型金矿床成矿特征

内蒙古额济纳旗老硐沟金矿原生矿化与闪长玢岩脉和似斑状花岗闪长岩株有关.金-多金属矿脉产于蓟县系平头山群白云石大理岩中,主要受近E-W向和NWW向断裂控制.氧化-淋滤型金矿床的形成,乃是原生低品位金矿化和次生淋滤富集两个过程的结果.在目前采深50m的淋滤带中,金多富集在距地表10~30m范围内.氧化矿石的矿物组合为臭葱石+砷菱铅矾+褐铁矿+针铁矿+砷钙锌石+羟砷锌石+自然金+自然银+石英+蛋白石.