摘要
难处理金矿是指不经过预处理,采用传统的选矿方法时金回收率较低的矿石,根据矿石成因不同,可大致分为三类:第一种是非硫化脉石包裹金;第二种是硫化物包裹金;第三种是含碳金矿,含碳金矿在氰化浸出过程中会发生“劫金”现象,影响氰化浸出的进行。对于碳和金伴生关系简单的矿石,一般可采用浮选工艺或浸出工艺进行,但对于矿石性质复杂的矿石,则需要增加焙烧氧化法、加压氧化法、化学氧化法、生物氧化法等预处理工艺。某金矿石金品位为1.96 g/t,金主要赋存在自然金中,粗颗粒金含量较高,矿石中有机碳含量高达1.39%,绿泥石、白云母、高岭石等黏土矿物总含量高,属于高含碳高含泥的难处理金矿。根据矿石性质和金矿物的嵌布特征,采用“原矿尼尔森重选—重选尾矿浮选—浮选精矿浸出”的选冶联合工艺回收矿石中的金,试验结果表明,采用羧甲基纤维素(CMC)作为脉石抑制剂,与使用水玻璃相比,可缩短浮选流程,显著提高浮选金精矿品位,金精矿品位可从22.47 g/t提升至32.95 g/t,减少浸出剂药剂用量,降低药剂成本。使用炭浸法工艺(CIL)浸金,活性炭可与矿石中的有机碳竞争吸附金,有利于消除因有机碳含量高所产生的“劫金”现象,较其他预处理工艺相比,成本低廉,环境污染小。采用该联合工艺,金综合回收率可达到90.93%,研究成果可为同类型矿石的开发利用提供参考。
Refractory gold ore refers to ores with low gold recoveries using traditional beneficiation methods without pre-treatment.Depending on the genesis of the ore,it can be roughly divided into three categories:the first type is non sulfide vein stone wrapped gold,which has a smaller particle size and is difficult to expose through conventional grinding.The second type is sulfide encapsulated gold,which is encapsulated in sulfide minerals such as pyrite and arsenopyrite,and fine grinding is not enough to expose the gold particles.The third type is carbonaceous gold ore,which contains some organic carbon in the ore,a"preg-robbing"phenomenon occurs during the cyanide leaching process,which affects the recovery of gold.Carbon and organic matter play a role in the pre-enrichment of gold during the mineralization process of micro disseminated gold deposits.When the organic carbon content in the primary ore is more than 0.2%,it will seriously interfere with cyanide gold extraction,and the carbon material will pre adsorb the dissolved gold ions during the cyanide process,which is called the"preg-robbing"phenomenon.For ores with a simple association between carbon and gold,flotation or leaching processes are generally used.However,for ores with complex properties,pre-treatment processes such as roasting oxidation,pressure oxidation,chemical oxidation,and biological oxidation are required.The roasting oxidation method is an effective way to significantly improve the cyanide leaching rate of gold by roasting and destroying the minerals that encapsulate the gold,thereby exposing the gold.It has always been one of the basic pre-treatment methods for high arsenic,high sulfur gold ores and carbon containing gold ores.However,the roasting process generates environmental pollution issues such as flue gas pollution(As2Og and SO_(2)),carbon emissions(CO_(2)),and requires additional operations such as alkaline or acidic leaching,grinding,and flotation.The pressure oxidation method is a pre-treatment process that exposes gold particles under certain temperature,pressure,and the action of acid or alkali,creating conditions for subsequent cyanide leaching of gold.According to the different oxidation media,there are two processes:acidic media and alkaline media.Currently,most of the pressure oxidation pretreatment plants that have been built and put into operation in the world are carried out under acidic media conditions.Chemical oxidation method is the use of strong oxidants to oxidize sulfur and arsenic minerals that encapsulate gold in gold ores,exposing the gold.This method includes nitric acid pre oxidation,alkali pre oxidation,potassium permanganate pre oxidation,peroxide pre oxidation,etc.The advantage of chemical oxidation method is that it does not require high equipment requirements,has low cost,is conducive to investment and construction,can be completed under normal pressure,and has mild operating conditions,simple control,and easy operation.The disadvantage is that strong oxidants can corrode equipment.Biological oxidation technology is a pretreatment method that utilizes microorganisms in nature to select sulfur and iron loving leaching strains.Through adaptive cultivation and domestication,these microorganisms can directly or indirectly oxidize and decompose the sulfide mineral matrix in a suitable environment,using the direct effect of their metabolism or the indirect effect of their metabolites.This method destroys harmful components such as pyrite and arsenopyrite that encapsulate gold,fully exposing the gold.It has the advantages of low cost,low pollution,low energy consumption,high leaching rate,simple process,and easy operation.The disadvantage is that the treatment time is greatly affected by the growth of the strains,and selectivity is greatly affected.The gold grade of a gold ore is 1.96 g/t,and the gold mainly occurs in the natural gold,with a high content of coarse-grained gold.The organic carbon content in the ore reaches 1.39%,and the total content of clay minerals such as chlorite,muscovite,and kaolinite is relatively high.The ore is a refractory gold ore with high content of carbon and slime.Based on the ore properties and the dissemination characteristics of the gold minerals,a combined beneficiation and metallurgical process was used to recover gold from the ore,consisting of"Knelson gravity separation of raw ore-flotation of gravity tailings-leaching of flotation concentrate".The results showed that using carboxymethyl cellulose(CMC)as gangue minerals depressant,compared to sodium silicate,can shorten the flotation process,significantly enhance the grade of the flotation gold concentrate,the grade of gold concentrate can be increased from 22.47 g/t to 32.95 g/t,and decrease reagent usage.By using the carbon-in-leach(CIL)process,activated carbon can compete with organic carbon in the ores to adsorb gold,which is beneficial for eliminating the"gold robbery"phenomenon due to high organic carbon content.With this combined process,the gold recovery can achieve 90.93%,which can provide technical reference for the similar ores.
作者
汤亦婧
罗思岗
赵志强
李丽
王国强
陆红羽
武煜凯
TANG Yijing;LUO Sigang;ZHAO Zhiqiang;LI Li;WANG Guoqiang;LU Hongyu;WU Yukai(BGRIMM Technology Group,Beijing 100160,China;State Key Laboratory of Mineral Processing,Beijing 102628,China)
出处
《有色金属(选矿部分)》
2025年第5期63-71,共9页
Nonferrous Metals(Mineral Processing Section)
基金
中国和乌兹别克斯坦政府间联合研发项目(2022YFE0126700)。
关键词
含碳金矿
炭浸法
脉石抑制剂
羧甲基纤维素
劫金
高含泥
carbon-bearing gold ore
carbon-in-leach process
gangue minerals depressant
CMC
preg-robbing
slime
作者简介
汤亦婧(1995-),女,黑龙江大庆人,硕士,工程师,主要从事有色、稀贵金属选矿工艺及药剂研发工作。
