氰化尾渣综合利用工艺分析与探讨

介绍了我国黄金矿山综合开发利用及含铜、砷浮选金精矿氰化尾渣处理的现状;分析了影响金银浸出的原因及机理。试验研究表明,通过加入混合添加剂、采用两段焙烧、氰化前加入助浸剂共磨,氰化尾渣中金、银的浸出率分别提高到82.92%和61.54%,浸渣中金、银品位分别降至0.55 g/t和30 g/t。     

Complex treatment of mining and metallurgical wastes for recovery of base metals

A complex process for the recovery of copper and zinc from mining and metallurgical wastes has been investigated and proposed. It includes sulfuric acid leaching of old pyrite flotation tailings to produce ferric containing leach solution; followed by ferric leaching of copper converter slag flotation tailings with the leach solution. A sample of old pyrite flotation tailings from the concentrator containing 0.36% of copper and 0.23% of zinc was leached with 10% sulfuric acid in the column. Recovery of copper and zinc reached 47.1% and 47.2%, respectively. The pregnant leach solutions contained 15.9 g/L of ferric iron. The subsequent ferric leaching of copper converter slag flotation tailings containing 0.53% copper and 2.77% zinc with the pregnant leach solution was conducted. The effects of various process parameters on the leaching dynamics of metals under batch conditions were investigated. Under the best conditions (temperature 70 °C, pulp density 30%, ferric iron concentration 15.9 g/L, initial pH of the pulp 0) the recovery of copper and zinc reached 79.6% and 43.7%, respectively. It was concluded that acid leaching of base metals from old pyrite flotation tailings with pregnant leach solution for the ferric leaching of copper converter slag flotation tailings is a prospective and promising technique for the complex treatment of mining and metallurgical wastes.     

A kinetic and electrochemical study of the ammonia cyanide process for leaching gold in solutions containing copper

One of the biggest challenges for the gold industry in the 21st century is the presence of copper in gold containing ore bodies. This is because copper consumes large quantities of cyanide. In addition, copper cyanide species are more stable than free cyanide, and hence are problematic in events of tailings spillage. One of the methods which has been suggested for treating copper containing ores is to leach with an ammonia cyanide solution. The effect of copper and ammonia addition on gold leaching kinetics was studied in the present paper. It will be shown that when the solutions do not contain copper, the addition of ammonia decreases the rate of gold leaching. When copper is added to solution, the leach rate does decrease due to the formation of the copper cyanide complexes. However it will be shown that under conditions of zero free cyanide, gold does leach readily via the Cu(CN)₃²⁻ complex. It was found that the addition of ammonia had little effect on the leaching of gold by Cu(CN)₃²⁻, but did increase the leaching kinetics when the major cyanide species present is Cu(CN)₂⁻. Under these conditions, leaching in the absence of ammonia is very slow. The effect of copper(II) addition was also studied, and it was found that in the absence of free cyanide the presence of copper(II) increases the leach rate, provided there is enough ammonia to stabilise it against reaction with the copper(I) cyanide complexes.     

The role of metal-cyanide species in leaching gold from a copper concentrate

The cyanidation of copper-gold ores is a difficult issue owing to the ready formation of copper cyanide complexes during gold leaching. Moreover, the speciation of other metal cyanides in leach slurries and the interaction between them have not been researched extensively, and are of fundamental importance to gold mills.In this paper the role of the cyanide complexes of copper, silver, nickel, iron and zinc in gold leaching was investigated by examining the leaching of a copper concentrate. It was found that copper-cyanide and other metal cyanide species, including Ag, Fe, Ni and Zn, all play an important role in gold cyanidation under conditions of zero free cyanide. These species dissociate, and the cyanide made available by the dissociation leaches gold. These metals species then precipitate, usually as a hydroxide under typical leaching conditions. Silver is an exception, which may precipitate as a metal or AgCN species. When cyanide is present, the mechanism of copper-cyanide assisted gold leaching is the dissociation of the weakly bound fourth ligand of Cu(CN)₄³⁻. The cyanide made available can then be used to leach gold and other metals.     

西藏某石英脉型金矿选矿试验研究

西藏某石英脉金矿主要载金矿物为银金矿,嵌布粒度较细且不均匀,金品位3.22g/t,为主要回收元素,银品位19.50g/t,为可综合回收元素。针对矿石性质,采用浮选-浮选尾矿氰化浸出联合工艺流程对矿石中的金进行回收。经一粗一精二扫、中矿顺序返回的闭路浮选流程,可获得浮选金精矿含金95.81g/t、金回收率84.34%的指标;浮选尾矿进行氰化浸出,金作业浸出率为79.31%,对原矿回收率为12.42%。联合工艺最终获得金总回收率96.76%的指标。其中浮选金精矿中银品位为407.01g/t、金尾矿中银品位为5.97g/t、精矿银回收率为68.78%,氰化浸出作业中银作业浸出率为51.53%,对原矿浸出率为15.98%,银综合回收率为84.76%。     

综合利用含锑砷金精矿关键集成技术试验研究

针对某含锑砷金精矿,通过直接氰化试验、两段焙烧氰化试验、直接氰化—浮选回收锑—浮选尾矿两段焙烧氰化试验等工艺技术进行试验研究。结果表明,采用一级直接氰化、二级氰化尾矿浮选富集锑精矿、三级为锑浮选尾矿两段焙烧氰化关键集成技术方法,含锑含砷金精矿直接氰化金、银浸出率分别为31.22%、85.19%,氰化尾矿浮选产出锑含量为38.80%的锑精矿,精矿产率为10.50%,锑回收率达到90.94%,锑浮选尾矿采用两段焙烧氰化金、银回收率分别达到90.07%、52.70%,该关键集成技术方法使金、银、锑的综合回收率分别达到93.56%、92.99%、90.94%,显著提高了有价金属资源的综合回收效果,实现了含锑砷金精矿资源的高值化、资源化利用。     

云南某铜金多金属硫化矿选矿试验研究

以云南某铜金多金属硫化矿为研究对象,通过优先浮选获得铜精矿、硫精矿;浮选尾矿经过磁选选铁,获得合格的磁铁精矿;磁铁精矿再磨后氰化浸出回收金,浸金渣作为磁铁精矿产品进行销售。铜、金、铁和硫均得到综合回收。     

Evaluation of leaching parameters for a refractory gold ore containing aurostibite and antimony minerals: Part I – Central zone

A cyanidation study was conducted on a mild refractory gold ore sample from the Central zone of Clarence Stream Property, owned by Freewest Resources Canada, to develop a leaching strategy to extract gold. Gold, at a grade of 8.00 g/t, is present as native gold, electrum and aurostibite. The ore also contains 2.8% pyrrhotite, together with several antimony minerals (0.8% berthierite and gudmundite, 0.18% native antimony and stibnite). It also exhibits weak preg-robbing properties with 0.16% organic carbon. Aurostibite, a gold antimony compound, is particularly known to be insoluble in cyanide solution. The antimony dissolves in cyanide solution to form antimonates, which retards gold dissolution. Industrial practice of extracting gold from aurostibite generally consists of producing a flotation concentrate, which is leached in a pipe reactor at low alkalinity and high oxygen pressure with about 20 g/L cyanide.The proposed new approach is efficient and allows the extraction of gold directly from an ore at atmospheric pressure and a low cyanide concentration at pH 10.5. The effects of grinding, pre-treatment, lead nitrate, kerosene and cyanide concentrations have been investigated. The maximum gold extraction obtained on the ore was 87.9% using 800 ppm NaCN, 500 g/t lead nitrate, 30 g/t kerosene, DO (dissolved oxygen) 10 ppm and pH 10.5 in 168 h. The associated cyanide consumption was 1.3 kg/t. The additions of lead nitrate and kerosene increased gold extraction. In comparison to a P₈₀ of 74 μm, a P₈₀ of 30 μm significantly increased gold extraction. Gold in solid solution in gudmundite and arsenopyrite was believed to be responsible for the un-leached fraction until mineralogical analysis of hydroseparation concentrates of leach residues showed that most of the un-leached gold occurs as aurostibite, either as locked grains in sulphides/sulpharsenides or as grains with passivation rims of an Au–Sb–O phase. Coarse gold was also found. Gold extraction was not sensitive to cyanide concentration from 250 to 1200 ppm NaCN and high pH was detrimental. Decreasing the cyanide concentration reduced the cyanide consumption from 1.39 to 0.85 kg/t. The removal of coarse gold using a Knelson concentrator and a Mosley table prior to leaching increased the gold extraction to 90.4% (leach residue at 0.77 g/t).     

某石英脉型微细粒嵌布低品位金矿石选矿试验

为了给某石英脉型微细粒嵌布低品位金矿石的开发利用提供依据,根据矿石性质,采用浮选-浮选尾矿氰化浸出-浮选精矿焙烧后氰化浸出工艺流程进行了选矿试验。结果表明：浮选-尾矿氰化浸出可获得金品位为61.88 g/t、砷含量为4.21%、金回收率为77.57%的金精矿和作业金浸出率为75.85%、对原矿金回收率为17.02%的尾矿浸出液,两者的金回收率合计达到94.59%。金精矿经焙烧预处理,焙砂砷含量降到0.38%、金品位提高到88.40 g/t;焙砂氰化浸出的作业金浸出率达93.28%、对原矿金回收率为72.36%,金精矿焙砂和浮选尾矿氰化浸出的综合金回收率为89.38%。     

The effect of zinc cyanide on the flotation of gold from pyritic ore

In gold processing plants, the process water contains a considerable amount of weak acid dissociable (WAD) cyanide species. The cyanide-containing water recycled to flotation circuits has a deleterious effect on mineral flotation. Zinc cyanide can be a major constituent of the process water due to the cyanide leaching of zinc minerals and the zinc cementation applied to precipitate gold and silver. In the present study, the effect of zinc cyanide on the flotation of gold from a pyritic ore was evaluated and the competitive adsorption between zinc cyanide species and the collector, potassium amyl xanthate (PAX) or Aerophine promoter (3418A), on gold was studied by surface enhanced Raman spectroscopy (SERS). It was found that free cyanide did not depress the flotation of liberated gold, but zinc cyanide with a CN/Zn ratio of 2 did. The depression of gold flotation by zinc cyanide was due to the preferential adsorption of Zn(CN)₂ on gold surface over either 3418A or amyl xanthate in the solution, rendering gold surface hydrophilic.     

The influence of pyrite pre-oxidation on gold recovery by cyanidation

The influence of pyrite pre-oxidation in alkaline solutions on gold recovery by cyanidation from Twin Creek refractory gold ore in which pyrite was identified as the major sulfide mineral has been investigated with the aid of electrochemical measurements, leaching experiments, and direct analysis of reaction products for selected residues. It was found that gold recovery by cyanidation in bottle roll experiments mainly depended on the extent of pyrite pre-oxidation. The rate of pyrite oxidation in alkaline solutions measured by electrochemical measurements, including chronoamperometry and linear sweep voltammetry, increased with an increase in pH, potential, and temperature. All alkaline reagents used for the electrochemical measurements, NaOH, NH₄OH, Na₂CO₃ and Ca(OH)₂, showed a similar effect on pyrite oxidation kinetics. However, the results of alkaline pre-oxidation for pyrite of the Twin Creek refractory gold ore suggested that NaOH and Na₂CO₃/Ca(OH)₂ were superior to Ca(OH)₂. Without pre-oxidation, cyanide leachable gold was found to be only 20% which could be increased to 70% under appropriate pre-oxidation conditions. At the same time, cyanide consumption decreased from 2.5 kg/t ore to 1.5 kg/t ore.Selected residues after pre-oxidation and cyanidation were examined by X-ray diffraction. Backscattered electron images of pyrite particles in these residues were taken. The reaction products at the surface of pyrite particles were found to be iron-, silicon-, and calcium-bearing compounds with variable amounts of sulfur as determined by X-ray energy dispersion analysis. Additionally, some mineral fines, such as aluminum and/or potassium-bearing minerals, were found to be present at the partially oxidized pyrite surface.     

Extraction of hydrogen cyanide from waste solutions of cyaniding circuit for sulfide flotation concentrates

The process for extraction of hydrogen cyanide to decontaminate solutions produced at cyaniding of sulfide flotation concentrates is developed. The centrifugal-bubbling apparatus is employed as a reactor. The regularities of HCN formation in an acid medium are established in investigation into kinetics of SCN⁻ thiocyanate oxidation by hydrogen peroxide H₂O₂ in presence of Fe²⁺, Fe³⁺ and pH ≤ 3.5. In the process proposed the evolved HCN is adsorbed by NaOH solution and returned to the circuit of leaching of gold and silver as NaCN, and the waste cyaniding solution is discharged into a waste dump, where it is mixed with industrial water to be utilized to transport flotation tailings. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 98–105, January–February, 2009.     

河北某难选银矿选冶工艺试验研究

河北省某难选银矿中银矿物种类多且嵌布特征复杂,在工艺矿物学研究基础上,通过选矿方案对比,采用浮选—浮选尾矿氰化联合工艺流程。浮选试验研究了磨矿细度、矿浆PH值、组合捕收剂丁基黄药和FZ-9538用量等条件对银回收率的影响,确定了最佳工艺条件,闭路试验可获得银品位3145g/t、回收率82.52%的银精矿;浮选尾矿含银42g/t,经氰化浸出24小时后,银浸出率为65.48%,对原矿回收率11.45%,浮选加氰化总回收率93.97%。     

高氰高碱条件下从氰化尾渣中综合回收金银铅锌的研究与应用

青海某金矿氰化车间产生的氰化尾渣中,含有金、银、铅、锌等有价元素,其中金品位2.68g/t,银品位28.76g/t,铅品位1.27%左右,锌品位1.05%左右,均具有较高的回收利用价值。利用浮选工艺,在高氰高碱度介质中,在对氰化尾渣进行擦洗性磨矿,破坏金属矿物被氧化的矿物表面后,采用一次粗选、两次扫选、两次精选的浮选流程,最终获得了铅+锌品位33.45%、金品位16.26g/t、银品位332.84g/t的浮选精矿,同时氰化尾渣中的砷被抑制,精矿中的砷品位仅为0.35%,实现了资源的综合回收。     

某含铜银矿石选别工艺优化研究

某矿山采用银浮选-银精矿氰化浸出-浸出尾渣浮铜工艺处理其含铜银矿石,存在铜大量消耗氰化物以及铜受氰化物作用不易回收等问题。为此,提出了原矿先通过优先快速浮铜得到一部分铜精矿,然后再进入原工艺流程的优化方案,并就快速浮铜和随后的银浮选进行了实验室试验。结果表明：优先快速浮铜可从原矿先获得一部分铜品位为25.02%,铜回收率为43.82%的合格铜精矿,同时可使银精矿中的铜含量达到1.80%的较低水平,将有利于减少铜的损失和改善后续银的氰化浸出环境。     

某低品位多金属金矿综合回收试验研究

某低品位多金属金矿中含有金、银、铅、铁等多种有价元素,有用矿物嵌布关系复杂且粒度较细,含量较低但综合利用价值较高。原矿在磨矿细度-0.074mm含量60%、捕收剂丁黄药和丁铵黑药用量分别为64g/t、13g/t的条件下进行混合浮选,获得金、银、铅混合精矿。混合精矿在pH值为11、矿浆浓度40%、氰化钠用量5kg/t、浸出时间36h的条件下进行氰化浸出获得金、银,对原矿金、银回收率分别为67.24%、38.30%。浸渣在抑制剂氧化钙用量1500g/t、捕收剂乙硫氮和丁铵黑药用量分别为40g/t、10g/t的条件下进行浮铅试验,获得了对原矿铅品位45.32%、回收率53.98%的铅精矿和对原矿回收率为3.16%、5.07%的金、银,金、银总回收率分别为70.40%、43.37%。混合浮选尾矿在磁场强度为111kA/m的条件下,通过一段粗选一段精选,获得了铁品位56.30%、回收率12.76%的铁精矿。采用此工艺综合回收了有价金属,获得了较好的选别指标,为该矿的开发利用提供了重要依据。     

某硫锌型深海多金属硫化矿选矿技术研究

某硫锌型深海多金属硫化物锌、硫品位分别为20.44%和36.6%,贵金属金、银分别为6.89g/t和141g/t。根据矿石性质,通过硫(自然硫)-锌的优先浮选工艺,先获得自然硫精矿,再获得锌精矿。闭路流程可获得硫品位70.36%、硫回收率23.09%、锌品位14.61%、锌回收率8.34%的自然硫精矿,以及锌品位49.90%、锌回收率85.56%的锌精矿。锌总回收率93.90%。对浮选尾矿进行氰化浸出,样品中的金、银元素选冶总回收率可分别达到83.3%和86.3%左右。     

某高硫含砷碳低品位难处理金矿选矿试验研究

某低品位金矿石原矿含金1.68 g/t,砷0.43%、碳0.40%、硫3.20%,金以显微或次显微形式浸染于毒砂、黄铁矿、褐铁矿中,具有载金矿物粒度细、砷和碳含量高等特点,是典型的低品位含砷碳极难处理 金矿石,严重影响金的浮选指标。为回收利用矿石中的金,分别进行了直接全泥氰化浸出、重选、浮选三种方案对比试验研究。结果表明,直接全泥氰化浸出率仅5%,重选金精矿回收率不足10%,浮选可获得金品位 15.04 g/t、回收率77.13%的金精矿。由于浮选金精矿含砷、碳、硫有害元素均较高,浮选尾矿含金0.42 g/t,损失较高,因此试验采用焙烧预处理以脱除金精矿和尾矿中的有害元素,然后焙砂氰化浸出回收金。最终 试验采用浮选—金精矿焙烧氰化浸出—尾矿焙烧氰化浸出联合工艺,得到金总回收率70.66%的较好指标,有效地回收了矿石中的金。     

The leaching and adsorption of gold using low concentration amino acids and hydrogen peroxide: Effect of catalytic ions,sulphide minerals and amino acid type

The leaching of gold using alkaline amino acids–hydrogen peroxide solutions at low concentrations has been studied. The application of alkaline amino acid–hydrogen peroxide system may offer an alternative and environmentally benign process for gold leaching, particularly in the context of leaching low grade gold ores in an in-situ or in heap leach processes. In the presence of an oxidant or oxidants, it was found that amino acids can dissolve gold at alkaline condition at low and moderate temperature. Heating the leach solution between 40 and 60 °C was found to enhance the gold dissolution significantly in alkaline amino acid–peroxide solutions. It was also found that gold dissolution increases by increasing amino acid concentration, peroxide and pH. Amino acids acts synergistically to dissolve gold. Although glycine showed the highest gold dissolution as a single amino acid compared to histidine and alanine, histidine was found to enhance gold dissolution when used in equimolar amounts with glycine. The presence of Cu²⁺ ion enhances gold dissolution in the glycine–peroxide solutions. The process will propose an environmentally benign process for gold treatment in order to replace the use of cyanide in heap or in-situ leaching. In the presence of pyrite, the amount of gold leached was lower due to the peroxide consumption in sulphide oxidation.     

某银矿中银的选矿试验研究

某银矿石中的银矿物嵌布粒度非常细,含锰高,增加了矿石中银的回收难度。采用直接浮选或氰化流程,银的回收效果不好。试验采用除锰后浮选、粗选和扫选精矿及氰化流程,在适宜条件下,获得了浮选、氰化银总回收率81.77%的技术指标;采用除锰后直接氰化流程,在适宜条件下,获得了氰化浸出率91.38%的较好指标。同时,矿石中的金也可得到综合回收和利用。