Biooxidation-thiosulfate leaching of refractory gold concentrate

A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated.Mineralogical studies on the concentrate showed that very fine gold grains(<10μm)were encapsulated in pyrite and arsenopyrite,while the proportion of monomer gold was only 21%.The gold-bearing sample was identified as a high-sulfur fine-sized wrapped-type refractory gold concentrate.The gold leaching efficiency obtained by direct cyanidation was only 59.86%.After biooxidation pretreatment,the sulfide minerals were almost completely decomposed,92 wt%of the mineral particles of the biooxidation residue were decreased to<38μm,and the proportion of monomer gold in the biooxidation residue was over 86%.Meanwhile,the gold content in the biooxidation residue was enriched to 55.60 g/t,and the S,Fe,and As contents were reduced to approximately 19.8 wt%,6.97 wt%,and 0.13 wt%,respectively.Ammoniacal thiosulfate was used for gold extraction from the biooxidation residue of the refractory gold concentrate.The results showed that the optimal reagent conditions were 0.18 M thiosulfate,0.02 M copper(II),1.0 M ammonia,and 0.24 M sulfite.Under these conditions,a maximum gold leaching efficiency of 85.05%was obtained.

Intensified alkaline leaching pretreatment of refractory gold concentrates at common temperature and pressure

A new process for the hydrometallurgy of refractory gold concentrates was presented. The process comprises grinding leaching, intensified alkaline leaching (IAL), cyanidation and adsorption. In a stirring type pulverizing leaching tower mill, the concentrate is ground to <35.6 μm of 95.5 % while simultaneously leached by NaOH of 12 kg/t, then carried out intensified alkaline leaching for 48 h by NaOH of 108 kg/t in enhanced agitation tanks with the pulp concentration of 40% solids at the environmental temperature of 9.5 ～ 13.5 ℃ and the environmental pressure of 10 5 Pa. The oxidation rate of As is 94.9%, and 47.6% for S. The total consumption of NaOH is only 20% of that theoretically calculated under the conditions of full oxidation at the same oxidation rates of arsenic to arsenate and sulfur to sulfate. The gold leaching rate by NaCN in 24 h is increased from 9.2% before pretreatment to 94.2%. The consumption of NaCN is 7.5 kg/t, which is one times less than that before pretreatment. The extraction cost of gold is about 422 Yuan/t.

Pretreatment and thiosulfate leaching of refractory gold-bearing arsenosulfide concentrates

A hydrometallurgical process for refractory gold-bearing arsenosulfide concentrates at ambient temperature and pressure was presented, including fine grinding with intensified alkali-leaching （FGIAL）, enhanced agitation alkali-leaching （EAAL）, thiosulfate leaching and displacement. Experimental results on a refractory gold concentrate showed that the total consumption of NaOH in alkaline leaching is only 41% of those theoretically calculated under the conditions of full oxidization for the same amount of arse- nides and sulfides transformed into arsenates and sulfates, and 72.3% of gold is synchro-dissoluted by thiosulfate self-generated during alkaline leaching. After alkaline leaching, thiosulfate leaching was carried out for 24 h. The dissolution of gold is increased to 91.9% from 4.6% by cyanide without the pretreatment. The displacement of gold by zinc powder in the solution gets to 99.2%. Due to an amount of thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal.

A new extraction process of carbonaceous refractory gold concentrate

A new hydrometallurgical process for a carbonaceous refractory gold concentrate at ambient temperature and pressure was presented, including grinding-leaching, intensified alkaline leaching(IAL), thiosulfate leaching and cementation by zinc powder. The experimental results show that the grinding-leaching and intensified alkaline leaching process result in the selective oxidation of arsenopyrite and pyrite. The oxidation ratio of As is 96.6%, and 46.7% for S. The total consumption of NaOH in alkaline leaching is only 28% of that theoretically calculated under the conditions of full oxidization for the same amount of arsenopyrite and pyrite transforming into arsenates and sulfates, and 83.6% of gold is synchro-dissoluted by thiosulfate self-generated during pretreatment. Since the carbonaceous matter in concentrate possesses a strong capability of preg robbing, the cyanidation process is not suitable for the extraction of gold after pretreatment. However, the gold leaching rate by thiosulfate leaching for 24h is increased to 91.7% from 03.2% by ultra-fine grinding without the pretreatment. The recovery of gold by zinc cementation gets to 99.6%. Due to the thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal one.

某高硫含砷难处理金矿选冶试验研究

针对某金矿中硫、砷含量过高且易泥化导致金回收率低的问题,采用阶段磨矿阶段浮选—浮选尾矿非氰浸出工艺流程开展试验研究。研究结果表明:在一段磨矿细度-0.074 mm占75.6%、二段磨矿细度-0.043 mm占78.1%,酸化水玻璃用量为1 650 g/t,硫酸铜用量为350 g/t,丁基黄药+丁铵黑药用量为(240+96) g/t,松醇油用量为160 g/t的条件下进行浮选试验,浮选尾矿采用非氰浸出剂进行非氰浸出,最终获得了浮选金精矿金回收率84.40%,浮选尾矿金浸出率10.52%,总金回收率94.92%的回收指标。研究结果对开发该类金矿资源具有重要指导意义。

塔吉克斯坦某含砷金精矿两段焙烧—浸出试验研究

塔吉克斯坦某含砷金精矿金品位73.27 g/t、砷品位6.61%、硫品位16.78%,是典型的难处理金精矿,采用直接氰化炭浆工艺处理时,金浸出率仅为88.02%。为提高金浸出率,进行含砷金精矿两段焙烧—浸出试验研究,制得的焙砂使用环保型浸出剂浸出。最终得到浸渣金品位4.32 g/t,金浸出率95.43%的良好指标,金浸出率提高7.41百分点,对处理同类型金矿资源起到指导作用。

氯离子对难处理金精矿生物预氧化-炭浸氰化的影响

高盐矿区往往缺乏淡水资源供生产使用。针对矿区盐水现状,进行高砷难处理金精矿生物氧化-氰化提金试验,考查不同氯离子浓度对硫化物氧化率、金浸出率等技术指标的影响。结果表明,氯离子浓度对金精矿生物氧化的不利影响随着浓度的升高而增强,氯离子浓度1.5 g L以上时,硫化物的氧化率显著降低,10 g L氯离子盐水生物氧化延长至18 d,砷浸出率88.4%,硫氧化率仅为35.3%。相同生物氧化渣在相同氰化条件下采用清水和10 g L氯离子盐水进行氰化浸出时,盐水将降低金的浸出率。1.5 g L、5 g L氯离子盐水生物氧化10 d后的氧化渣采用10 g L氯离子盐水氰化,金的浸出率分别比清水氰化时的分别低2.8、3.4个百分点。难处理金精矿生物氧化砷浸出率均高于硫氧化率,表明毒砂氧化率高于黄铁矿,金浸出率与毒砂氧化率的相关性较黄铁矿氧化率更加密切。

某复杂难处理硫精矿综合回收的试验研究

以昆明某复杂难选硫精矿为原料,先在马弗炉中进行了焙烧脱硫砷的条件试验,得出了焙烧的最佳操作条件后,以沸腾炉(工业生产炉床面积74 m^(2))中产出的烧渣为原料进行了氰化提金银的条件试验。该硫精矿综合处理的最佳条件为:焙烧温度840~870℃,焙烧时间2~2.5 h;烧渣磨矿细度-0.038 mm≥90%,氰化钠加入量2 kg/t,浸出液固比2∶1等,此时硫脱除率达99%以上,金浸出率达84%;经分析氰化尾渣可作为铁精矿出售。该项目已在云南某企业建成处理量300 t/d复杂含金硫精矿提金的工业生产线。

难处理含金硫精矿的焙烧氧化-硫代硫酸盐浸出

为了提高难处理含金硫精矿中金的浸出率,采用同步热分析仪研究在马弗炉中焙烧氧化难处理含金硫精矿的最佳条件,通过优化实验确定硫代硫酸盐浸出的最佳工艺参数。结果表明:在马弗炉中焙烧氧化难处理含金硫精矿最佳条件为在700℃温度下焙烧2 h,难处理含金硫精矿硫的去除率可达94.7%。焙烧后,金的浸出率大幅度提高。使用组成为0.03 mol/L CuSO4、1.0 mol/L NH3·H2O、0.3 mol/L Na2S2O3、0.1 mol/L(NH4)2SO4和0.3 mol/L Na2SO3的硫代硫酸盐溶液作为浸出剂,最佳浸出工艺参数如下:浸出时间18 h、液固比2:1、振荡速度250 r/min、浸出温度50℃。在此浸出工艺参数下,金浸出率达71.2%。

含砷、锑难处理金精矿提金工艺研究

某含砷、锑金精矿直接氰化金浸出率仅42.79%,采用常规焙烧—氰化工艺金浸出率仅48.22%,而采用碱浸—两段焙烧—磨矿—氰化工艺金浸出率达到了86.3%。同时锑脱除率达到了96.6%,也可作为产品外售。

高砷硫金精矿提金研究

广西贵港金精矿含15%～22%As,并含碳、铅等不利于氰化的元素,金直接氰化率8%～36%。采用催化氧化酸浸法预处理后,金氰化率可达92%～98%,氰渣浮选后精矿的金总收率达97%～99%。预氧化工艺在中温自热、低压、低酸操作条件下进行,废渣、废液符合环保要求。多批次小型试验及扩大试验结果表明该工艺技术指标稳定,经济可行。

湖南某高砷难处理金精矿的细菌氧化-氰化提金实验研究

湖南某高砷金精矿属于难处理矿石,含砷11.28%,含金66.18g/t,金的直接浸出率仅为21.91%。通过该样品5%、10%、15%、20%矿浆浓度的细菌氧化试验,发现金精矿砷的氧化率达到93%以上。细菌氧化渣的金浸出率随着矿浆浓度的增大而降低,5%矿浆浓度下细菌氧化渣的金浸出率为93.15%;10%矿浆浓度下细菌氧化渣的金浸出率为92.46%;15%矿浆浓度下细菌氧化渣的金浸出率为90.50%;20%矿浆浓度下细菌氧化渣的金浸出率为87.58%,比未经处理时金的直接氰化浸出率21.91%有了很大的提高,预处理效果很好。

湖南某难处理金矿的加压预氧化-氰化浸金试验研究

针对湖南某难处理金精矿进行预处理技术研究.该矿含砷(质量分数)为11.28%,金的直接氰化浸出率为21.91%.矿石中的砷以毒砂形式存在.载金矿物为毒砂和黄铁矿等硫化物,金为微细浸染型被毒砂和黄铁矿包裹.通过加压预氧化,对矿石进行氰化浸金试验研究.加压氧化最佳条件为初始酸度1 mol/L,木质素磺酸钠5 g/t,硝酸硫酸比7∶1,氧压0.6 MPa,搅拌速度300 r/min,时间100 min,温度100℃,矿浆浓度20%.试验表明经过加压试验后,金的氰化浸出率达到90.87%,与未预处理相比提高了68.96%,达到了较好的试验效果.

难处理金精矿的加压氧化-氯化浸出实验

采用加压氧化法对国内某难处理金精矿进行预处理,考察了反应温度、精矿粒度、氧分压、初酸浓度、反应时间对金精矿脱硫率和金浸出率的影响.利用XRD,XRF,SEM,EDX技术对金精矿原矿及浸出渣进行分析表征,实验结果表明,在反应温度180℃,精矿粒度-0.075^+0.061 mm,氧分压0.8 MPa,初酸质量浓度60 g/L,液固比4∶1,反应时间120 min,搅拌转速600 r/min条件下,金精矿的脱硫率为93.85%.以50 g/L的NaCl和8 g/L的NaClO混合溶液作为浸出剂,对加压氧化渣进行氯化浸出,在反应温度30℃,pH值4.5~5.0,液固比3∶1,搅拌转速300 r/min,浸出时间180 min条件下,金的浸出率为94.54%.未作预处理的金精矿直接氯化浸出,金的浸出率仅为42.65%,加压氧化对提高金的浸出率效果显著.

从难处理金精矿氯化浸金溶液中吸附金

对国内某难处理金精矿高压氧化渣进行氯化浸出及吸附试验。结果表明,在下述最佳条件下浸金率达到96.5%:次氯酸钠浓度10g/L、pH=4、氯化钠浓度75g/L、温度40℃、液固比3∶1、搅拌速度300r/min、时间120min。浸金液在室温采用1g/L的717阴离子交换树脂吸附30min,金吸附率达到99.2%。该方法污染少、操作简单、反应速度快。

含硫试剂对某难处理金精矿的浸出研究

在对某难处理金精矿进行工艺矿物学研究的基础上,用硫脲、硫代硫酸盐、硫氰酸盐和改性石硫合剂等含硫试剂对其进行了浸出试验研究。结果表明,该精矿属典型的黄铁矿与毒砂包裹的难处理金矿,约20%的金被包裹,改性石硫合剂可部分将矿物的包裹氧化,浸出率达80%以上,适用于此矿的浸出,并分析推测了浸出试剂与矿物的作用机理。

提高含砷金精矿二段焙砂金浸出率的研究

本文以某含砷金精矿二段焙烧焙砂为研究对象,针对焙砂中金主要被赤铁矿包裹的特点,采用硫酸溶液+助浸剂浸出的方法对包裹金进行有效解离,使包裹金充分暴露,达到提高金浸出率的效果。研究了硫酸浓度,酸浸温度,助浸剂加入量等因素对铁浸出率的影响及对酸浸渣氰化过程金浸出率的影响。在最佳工艺条件下,该工艺比工业生产常用的二段焙砂→酸洗→氰化金浸出率提高12%左右。

某金矿石浸渣浮选精矿预氧化及氰化提金研究

某金矿石氰化尾渣浮选精矿难浸,在<37μm占99.5%的磨矿细度下氰化浸出24h,金的浸出率仅有3.95%。采用常温常压碱性强化预氧化工艺处理后,金的浸出回收率提高到85.85%,炭吸附率99.62%。

用石硫合剂（LSSS）法从高铅金精矿浸出金

石硫合剂法是最新的无氰提金技术。石硫合剂法浸金机理是：电化学－催化机理。本文对石硫合剂法浸出高铅顽固金精矿样的工艺研究表明：石硫合剂法对顽固金精矿的适应性良好，采取二段浸出工艺，金浸出率可达９９％，为国内外大量顽固金矿的开发利用提供了条件和可能途径。

某毒砂金矿硫氰酸盐氨性体系加压氧化提金探索试验

对某毒砂金矿进行了硫氰酸盐氨性体系氧压提取金的探索试验,考察了反应温度、Cu2+浓度、浸出时间、液固比、氨水浓度、氧分压和硫氰酸铵浓度等对金浸出率的影响。结果表明,在下述优化条件下金浸出率为61.7%,即硫氰酸铵浓度3mol/L,液固比5∶1,反应温度150℃,浸出时间6h,搅拌速度750r/min,氨水浓度4.64mo/L,铜加入量1.5g/L。而经400℃焙烧预处理后金浸出率达到86.2%。