节点文献
某低品位金矿浸出工艺优化试验研究
【作者】 玉涵；
【导师】 胡显智；
【作者基本信息】 昆明理工大学 ， 矿物加工工程， 2010， 硕士
【摘要】 矿产资源是人类赖以生存、发展的重要自然资源,随着社会和科技的不断进步,矿石的选别技术也在不断地发展。由于人类对矿产资源的不断开采和利用,金矿储量正在不断地减少,且趋向于“贫、细、杂”化。因此,充分合理的开发金矿资源,尤其是低品位、难选金矿的综合利用,具有重要的经济意义和社会意义。青海某金矿为低品位金矿,矿石共生关系复杂、嵌布粒度较细,目标矿物分离的难度较大,搅拌氰化浸出时矿石中的杂质矿物对浸出不利,金的浸出率较低。本文对该金矿进行了光谱分析、化学多元素分析、金的物相分析,并针对这一矿石性质,进行了一系列的探索试验,得出如下结论：(1)对金矿试样性质研究结果表明：该矿石为石英脉型金矿,矿石中金的含量为2.76(10-6),主要以自然金的形式存在,此外还有少量的类质同象金。自然金主要以微细粒的形式存在,以裂隙金和包裹金为主,其中裂隙金占金总量的41.7%左右,包裹金主要存在于长石当中,占金总量的30.83%。此外,泥质中还存在少量的包裹金,占金总量的17.68%。类质同象金主要分布于金属硫化物中,其品位为13.2(10-6),占金总量的9.57%。(2)试验分别考察了磨矿细度、氰化钠浓度、浸出时间以及过氧化氢、漂白粉、硝酸铅、铵盐等助浸剂对氰化浸出的影响,尤其是几种铵盐及其用量对金氰化浸出的辅助作用。(3)试验数据表明,由于矿石中可溶性铜的存在,金在氰化过程中受到了较大的影响。在搅拌浸出最初的5小时内,杂质矿物消耗了溶液中大部分的游离氰化钠,金的浸出率偏低。当杂质基本溶解后,剩余的氰化钠才逐渐溶解矿石中的金。(4)试验结果证明,氨浸-氰化提金工艺对该金矿有良好的浸出效果。氨的加入使得矿浆的pH有所升高,促进了氢氧化铜沉淀的形成,降低了溶液中铜离子的含量；氨与溶液中的Cu-CN-络离子协同作用,促进了金的溶解。(5)综合考虑实地生产、矿石性质和经济成本等因素,最终确定该金矿氰化浸出的最佳条件为：磨矿细度95%-200目,矿浆浓度40%,矿浆pH为10-11,氰化钠浓度12/万,浸出时间24小时,氨水或氯化铵为助浸剂较为适宜,氰化钠与氨的摩尔比为1：2,获得金浸出率为87.5%,氰化钠用量为1.53 kg/t矿石的较好浸出结果。(6)简述了过氧化氢、漂白粉及硝酸铅等强化浸金过程的原理,着重叙述了氨氰提金工艺的机理和特点。氰化提金过程中,矿石中的可溶性铜会造成氰化钠的大量消耗,影响金的浸出。而氨浸-氰化提金技术是处理各种铜金矿最有效的方法,氨可以有效降低铜对浸金过程造成的影响,减少氰化钠的用量,提高金的浸出率。
【Abstract】 Mineral resources are important natural resources for human live and development. With the development of society and technology, mineral processing technology gets also developed too. Because of human constantly exploiting and utilizing mineral resources, the gold mine reserves is decreasing, and tend to be "poor, fine and complex". Therefore reasonably exploiting on gold resources, and especially comprehensive utilization for low-grade and refractory gold ore has important economic and social significance.In this paper a low-grade and refractory gold ore in Qinghai was studied. The granularity of embedding is small, so the target mineral is difficult to separate from and when blending the cyanide, the impurity in the ore is deleterious for leaching, thus, the rate of gold leaching is low.This paper conducted spectral analysis, chemical analysis and phase analysis on that gold ore, and carried series exploring tests based on its character, then got the following conclusions:(1) The test result shows that:this ore belongs to quartz vein-type gold ore. The gold in this ore is 2.76 (10-6). It mainly exists as natural gold format, and in addition, there are few isomorphism gold. Natural gold mainly exist as Micro-fine-grain, especially for fissure-filling gold and wrapped gold. Fissure-filling gold shares more or less 41.7%in the gold, where wrapped gold mostly exist in feldspar, and shares 30.83%in the gold. Besides, there are a little wrapped gold existing in clay, and it shares17.68%in the gold. Isomorphism gold mainly exists in Metal sulfides, its grade is 13.2 (10-6), and shares 9.57%of total gold.(2) The test investigated the effect on cyanide leaching by the impact of grinding fineness, sodium cyanide concentration leaching time, hydrogen peroxide, bleaching powder, lead nitrate, ammonium and other aid infusion. It especially investigated the supplement role of some ammonium salts and their consumption for cyanide leaching of gold.(3) The experiment shows that, due to the presence of dissolubility copper in the ore, gold leaching has been restarted in the cyanide process. In the first 5 hours of leaching, the impure mineral consumed most of free sodium cyanide of the liquor, in that case, the rate of gold leaching is low. When the impurities nearly dissolved, the remaining solution of sodium cyanide gradually dissolves the gold of ore.(4) The test results showed that ammonia leaching-cyanide gold extraction technique has good leaching result for that gold ore. Adding ammonia increased the PH value of ore pulp, it promoted the formation of cupric hydroxide precipitation, and reduced the content of copper ions in solution. Ammonia and the Cu-CN"ions of solution cooperate together, and then promoted the dissolution of gold.(5) Synthesis considering the field of production, minerals characters and economic costs, we definitely confirm the best condition for the cyanide leaching of that gold mine as follows:grinding fineness:95%-200 mesh, pulp density:40%, pulp pH value:10-11, sodium cyanide concentration:12/10000, leaching time:24 hours, ammonia or ammonium chloride is more appropriate to be assist infusion, the sodium cyanide and ammonia molar ratio is 1:2, gold leaching rate obtained was 87.5%, sodium cyanide dosage at 1.53 kg/tore will get better leaching results.(6) It outlines the principle of dipping gold process by hydrogen peroxide, bleaching powder and lead nitrate, and emphasized the introduction of ammonia-cyanide gold extraction mechanism and characteristics. In the cyanide gold extraction process, the soluble copper in the ore will cause a large number consumption of cyanide, and affect the gold leaching. The ammonia leaching-cyanide gold extraction technology is the effective method to deal with a variety of copper gold ore. Ammonia can effectively reduce the impact of copper on the process of leaching gold and reduce the consumption of sodium cyanide, then improving gold leaching rate.