【作者】 杨玮；

【导师】 覃文庆；

【作者基本信息】 中南大学 ， 矿物加工工程， 2011， 博士

【摘要】 目前,合理、高效、环保地开发利用难处理金矿资源己成为世界各产金国面对的主要技术问题,本文针对高铜含碳及含砷两种主要难处理金精矿,重点开展了高铜含碳金精矿添加助浸药剂强化浸出、氰尾浮选综合回收、生物氧化砷黄铁矿电化学、细菌氧化浸矿动力学及含碳高砷金精矿的预氧化提金等方面的试验研究,并在试验研究的基础上实施推广和工程化实践。高铜含碳金精矿的直接氰化浸出研究,研究了磨矿细度、浸出时间、氰化纳浓度、矿浆中溶解氧浓度和氧化铅用量等影响因素对金的浸出率和氰化钠消耗的影响,对常规浸出72h,金的浸出率和氰化钠单耗分别为89.48%和15.58kg/t的金精矿(含Cu2.28%),采用20mg/L氧溶解浓度和4kg/t氧化铅用量强化浸出48h,即可获得98.08%的金浸出率和5.60kg/t的氰化钠单耗指标,试验表明：富氧添加氧化铅强化处理高铜含碳金精矿,能有效抑制铜的浸出溶解和减少或消除碳对已浸出金的吸附,降低氰化钠的消耗量,可以显著强化氰化浸金效果。对多金属含硫金精矿直接氰化的浸渣,在考虑实施生产废水零排放的基础上,采用优先混浮分离后再分别进行铜铅分离和铅锌分离的技术路线综合回收铜铅锌等有价组分,试验表明：在利用贫液调浆的氰渣浮选综合回收中,游离氰根浓度和游离氧化钙浓度降低很快,保持二者浓度稳定有利于浮选分离,同时要充分考虑氰化体系中各重金属离子及其络合物对浮选的影响,依据要回收目的矿物选取合适的药剂制度和流程,在铜铅或者铅锌分离中,优先浮铅工艺更容易实现。通过考察TCJ混合菌种生长所需的适宜温度、pH值及有害离子耐受能力,研究其生长习性表明：该浸矿菌种可在33～45℃和pH值为0.8-1.8的范围内生长,最佳生长温度和pH值为40℃和1.5,对有害离子Cu2+Cl-及As3+的耐受极限浓度为10g/L、5g/L和3g/L,按照逐级放大的原则,重点对其耐氯能力和耐砷能力进行驯化,在金精矿氧化矿浆中TCJ菌耐受C1-浓度的临界值是2.7g/L,耐受矿浆中液相砷浓度的最高值为15g/L,可以处理含砷量在12%以下的金精矿,较好地提高了其活性和抗毒性能,为含砷难处理金精矿生物预氧化生产实践提供性能优良的浸矿复合型工程菌。利用线性扫描电化学测试技术,对砷黄铁矿在无菌和有菌的酸性介质中的氧化机理、电化学动力学及浸矿动力学进行研究,研究表明细菌的存在强化了阴极作用和砷黄铁矿与其它硫化矿物间的原电池效应,加速分解砷黄铁矿氧化过程产生的中间相,促进砷黄铁矿的氧化；在有菌9K培养基体系中,随着温度的升高,砷黄铁矿的腐蚀电位、阳极斜率、阴极斜率和极化电阻均降低,腐蚀电流密度增加,砷黄铁矿在温度高的体系中更容易被氧化腐蚀溶解；pH值在1.5-2.0区间变化时,砷黄铁矿电化学动力学参数变化不大,有利于细菌的生长繁殖和砷黄铁矿的稳定氧化,通过控制适宜的pH值,可以减少氧化体系中砷铁酸盐、铁的氢氧化物及单质硫的形成,提高砷黄铁矿氧化效果；电化学动力学和浸矿动力学研究表明,细菌的间接氧化机理在砷黄铁矿的氧化过程中发挥主导作用,含砷金精矿细菌氧化浸出动力学过程受固体产物层内扩散控制。通过对含碳高砷难处理金精矿细菌预氧化-氰化提金条件试验研究,优化氧化预处理和氰化浸出的工艺条件参数。对含碳高砷金精矿氧化预处理9d后,砷、铁及硫的脱除率分别达到95.77%、95.25%和86.64%,试样失重率为26.48%,氧化渣氰化浸出36h后,金和银的浸出率分别达到了95.68%和75.64%,比未经氧化预处理的金精矿常规氰化浸出72h的金、银浸出率分别提高了78.14%和24.71%,因此细菌氧化预处理不仅可以显著提高含碳高砷难处理金精矿的氰化浸出指标,而且还会大大缩短氰化浸出周期。采用富氧添加氧化铅氰化处理高铜含碳金精矿的工业化生产实践中,金的浸出率由常规氰化的88.56%提高到97.53%,氰化钠单耗由常规氰化的19.86kg/t降到11.68kg/t,在提高技术经济指标的前提下,有效生产能力由常规氰化的53.19t/d提高至72.8t/d,证明该工艺能有效提高金的浸出率,降低氰化钠单耗,缩短浸出时间,扩大生产能力。氰渣浮选综合回收生产实践表明,利用浮选的方法综合回收氰渣中铜铅锌是可行的,适宜的作业条件下能够生产出合格的精矿产品,但必须根据氰渣的特性及成分组成,充分考虑各组分受氰化物抑制程度的差异,选择适合的浮选工艺,原则上采用优先浮铅工艺,同时须密切关注和控制产品中元素互含超标的问题,否则会因为杂质超标降低品级销售而大大影响产品质量和企业的效益。含砷金精矿细菌预氧化提金工程化实践表明,TCJ菌可以用来直接氧化处理含砷量高达8%的难处理金精矿,对于含砷高达21.89%的难处理金精矿,通过配入一定比例的低砷碳酸盐型金精矿,使给矿铁砷摩尔比在4.6～5.2之间,高砷金精矿的铁、砷氧化脱除率分别由6.14%和7.38%提高到89.90%和93.60%,金、银浸出率分别由64.18%和35.93%提高到97.78%和88.83%,改善细菌氧化和浸出效果显著。本论文的研究为高铜含碳和含砷难处理金精矿的直接氰化浸出和生物预氧化—氰化浸出提供了理论和技术上的指导。更多还原

【Abstract】 Recently rational, efficient and environment friendly exploitation and utilization of the refractory gold mineral resource have become the main challenge faced by every gold-producing country in the world. In this dissertation, researches on treatment of two kinds of refractory gold concentrates, high copper carbon-bearing and arsenic-bearing gold concentrates, were performed, including strengthening leaching of high copper carbon-bearing gold concentrate with leaching-aid reagent, comprehensive flotation recovery of cyanidation tailing, electrochemical study of biooxidation of arsenopyrite, leaching kinetic study of biooxidation of arsenic-bearing gold concentration and biooxidation-cyanidation of high carbon arsenic-bearing gold concentrate, and the technology extension and industrialization practice were conducted on the base of the fundamental researches.The effects of grinding size, leaching time, concentration of sodium cyanide, dissolved oxygen concentration and amount of lead oxide on the gold leaching and consumption of sodium cyanide were investigated in the study of direct cyanidation of the high copper carbon-bearing gold concentrate (Cu2.28%). For the conventional leaching,89.48%gold leached and15.58kg/t sodium cyanide consumed in72h. However for the strengthening leaching,98.08%gold leached and5.60kg/t sodium cyanide consumed in48h with20mg/L dissolved oxygen and4kg/t PbO. The results showed that when the high copper carbon-bearing gold concentrate was leached with addition of enriched oxygen and PbO, the dissolution of copper and the adsorption of carbon to the leached gold were inhibited, the consumption of sodium cyanide consumption was reduced and the gold leaching was enhanced.with the consideration of zero waste water diacharge, the polymetallic sulfide cyanidation tailing was treated by the technical route of bulk flotation-separation of copper and lead-separation of lead and zinc, the copper, lead and zinc were recovered comprehensively. The results showed that the cyanide and the calcium oxide concentration decreased rapidly in the flotation of cyanidation tailing with barren solution, keeping the steady concentration of these two reagents was good for the flotation of the metal sulfide minerals. According to the effect of every heavy metal ions and their complexes on the flotation of desired minerals, the proper reagent system and process flow were adopted, and the selective flotation of lead was easily achieved in the separation of copper and lead or lead and zinc.The optimal growth temperature, pH value and the toxic ions resistance of the TCJ mixed culture were investigated, the results indicated the culture could grow under the temperature from33to45℃and pH value from0.8to1.8, with the optimal temperature40℃and pH1.5, and could resist the toxic ions, Cu, Cl-and As3+up to10g/L,5g/L and3g/L respectively. The TCJ culture was adapted to the high concentrations of chloride and arsenic ions by gradually increasing the concentrations of these two ions in the slurry. The critical concentrations of chloride and arsenic ions for efficient biooxidation of gold concentrate were2.7g/L and15g/L respectively. After adaption, the culture could efficiently treat arsenic-bearing gold concentrate containing arsenic no more than12%, its activity and toxicity resistance of the culture were improved, and was suitable for the industrialization practice of biooxidation of arsenic-bearing gold concentrates.The oxidation mechanism and the electrochemical kinetic of arsenopyrite with or without bacteria and leaching kinetic were investigated by linear scanning electrochemical measurement technology. The research showed that the bacteria enhanced the cathodic process and the galvanic effect between arsenopyrite and other sulfide minerals, accelerated the dissolution of intermediate products and the oxidation of arsenopyrite. In the9K medium with bacteria, the corrosion potential, the anodic slope, the cathodic slope and the polarization resistance decreased, and the corrosion current density increased with the temperature rising, this result indicated the arsenopyrite was more easily dissolution by oxidation corrosion. The electrochemical kinetic parameters changed slightly between the pH1.5and2.0, which was beneficial to the bacterial growth and the steady oxidation of arsenopyrite. The formation of ferric arsenate, iron hydroxide and elemental sulfur could be reduced by controlling the pH of slurry and the oxidation effect of arsenopyrite could be improved. The electrochemical kinetic and leaching kinetic researches indicated the indirect oxidation mechanism in the biooxidaiton of arsenopyrite was predominant, the leaching kinetic process of arsenic-bearing gold concentrates was controlled by the solid product layer diffusion.The technical parameters of biooxidation and cyanidation of the high arsenic carbon-bearing gold concentrate were optimized by the conditional experiments. After9days’ biooxidation,95.77%arsenic,95.25%iron and86.64%sulfur were removed, the sample weight loss rate was26.48%. After36hours’ cyanidation, the extraction rates of gold and silver reached95.68%and75.64%respectively, which were78.14%and24.71%higher than that of72hour’s conventional cyanidation of untreated gold concentration. Therefore, the biooxidation not only remarkably enhance the cyanide leaching of gold, but also reduced the cyanide leaching time.In the industrialization practice of cyanidation of high copper carbon-bearing gold concentrates with addition of enriched oxygen and PbO, the gold extraction rate increased from88.56%for conventional cyanidation to9753%, the sodium cyanide consumption decreased from19.86kg/t for conventional cyanidation to11.68kg/t. On the premise of improving technical economical indexes, the actual capacity increased from53.19t/d for conventional cyanidation to72.8t/d, these results indicated the technology could effectively improve the gold extraction, lower the sodium cyanide consumption, reduce the leaching time and extend the productivity.The industrialization practice of comprehensive recovery of cyanidation tailing by flotation indicated the flotation of copper, lead and zinc from cyanidation tailing was feasible. Qualified concentrates could be produced under proper operating condition, however the discrepancies of degree of inhibition by cyanide of different components and the composition of cyanidation must be took into account when choosing the flotation technology, in principle, the selective flotation of lead technology was adopted. The problem of excessive impurities must be considered and controlled, otherwise the efficiency of enterprises would be impacted remarkably by the decreasing of products quality for the excessive impurities.The industrialization practice of biooxidation of arsenic-bearing gold concentrates showed that the TCJ culture was suitable to pretreat the refractory gold concentrate containing8%arsenic. For the refractory gold concentrate containing21.89%arsenic, after blending with low arsenic carbonate gold concentrate, the mole ratio of iron and arsenic was controlled between4.6%and5.2%, the biooxidation and the cyanidation of the high arsenic concentrate were remarkably improved:the removal rate of iron and arsenic by biooxidaton were enhanced from6.14%and7.38%to89.90%and93.60%respectively, the gold and silver extraction were increased from64.18%and35.93%to97.78%and88.83%respectively.The researches in this dissertation provide theoretical and technical guidance for the direct cyanidation of high copper carbon-beatring gold concentrates and biooxidation-cyanidation of arsenic-bearing refractory gold concentrates.更多还原