用于从氰化矿浆中提取金的353E大孔双官能团树脂的制备

研究了用二甲胺和三甲胺的混合物作胺化剂,控制混合胺中各组成比例,使所制备的353E大孔双官能团阴离子交换树脂中2种官能团的比例适当.该树脂孔径适宜, 分布均匀,总交换容量高,机械强度好,动力学性能好,适用于从氰化矿浆中提取金.     

Ultrasonic elution of gold from activated carbon

The feasibility of using ultrasound to enhance the elution of gold from activated carbon was investigated. A laboratory-scale elution column immersed in an ultrasonic bath was used to investigate three eluant systems. The kinetic activity of the activated carbon was improved in the elution with sonication. Ultrasonic radiation improved the recoveries and kinetics of elution considerably. This could possibly be attributed to an increase in diffusive transport caused by acoustic vortex microstreaming and microjets, as well as the prevention of activated carbon fouling which can lead to the blockage of active sites. The rate of elution was significantly increased by the addition of ethanol to the aqueous eluant, especially in the presence of ultrasound. It could be attributed to the increased activity of smaller ions in preference to gold cyanide in the presence of ethanol. Ethanol, by capturing the primary radicals (H^* and OH^*), generated secondary radicals (C₂H₄OH*) which could be responsible for the increased efficiency. The introduction of ultrasound into the conventional elution systems made it possible to elute gold cyanide from activated carbon under less severe conditions.     

Factors affecting the elution of Pt,Pd and Au cyanide from activated carbon

Several factors affecting the elution of Pt, Pd and Au cyanide complexes in a manner similar to the AARL process have been investigated. Temperature, the cyanide pre-treatment concentration and the ionic strength of the eluant have been found to affect Pt and Pd elution substantially and will be critical factors in the design of an elution process. An acid (HCl) pre-treatment step increased the elution percentage for all cases investigated while no PGMs were eluted by the acid. The presence of Cu did not have a negative effect on the elution of Pt, Pd or Au at strong pre-treatment (2% NaCN and 0.6% NaOH) conditions but at weak pre-treatment conditions (0% NaCN), the elution percentage of Pt and Pd were reduced by between 10% and 18% after five bed volumes when Cu was present. The presence of 100 mg/L KSCN salt added to the leach solution during the adsorption stage reduced the elution percentage for Pt and Pd by seven and 10%. Carbon loaded to equilibrium resulted in slower elution kinetics.     

The effect of salinity on the capacity and selectivity of ion exchange resins for gold cyanide

Despite the success of several resin-in-pulp pilot plant operations in the Western World and large scale plants in the former Soviet Union the process of extracting gold from slurries using ion exchange resins is yet to gain recognition as a viable alternative to the carbon-in-pulp process. An experimental research program has investigated the potential use of anion exchange resins containing a variety of quaternary ammonium functional groups in highly saline process water such as that found in Western Australia. The effect of univalent and bivalent ions on gold adsorption has been studied. It was shown that the selectivity of the resin for gold cyanide was enhanced with increasing ionic strength. It has been proposed that the degree of hydration, polarisation and size of the adsorbing species are factors that contribute to the observed change in selectivity of the ion exchange resin at different salinity. It was observed that in highly saline solutions copper cyanide did not load significantly on any of the experimental resins studied. Furthermore, it has been shown that an existing commercial non-selective resin loads no significant amount of copper cyanide under saline conditions. It is proposed that the apparent change in selectivity of resins for gold cyanide is caused by anions that have a stronger affinity for the resin in these highly non-ideal solutions as well as a possible change in the distribution of copper cyanide complexes in solution. The results of this study demonstrate that the selectivity of ion exchange resins in highly saline water is significantly improved and as a consequence the resin-in-pulp process may be more efficient than carbon-in-pulp in process streams of high salinity.     

强碱性阴离子交换树脂吸附锆、铪分配系数研究

通过静态试验法,测试了201×7、D290、D296 3种离子交换树脂吸附硫酸锆(铪)溶液中的锆、铪的两相分配系数K_d(Zr)/K_d(Hf)的比值。试验证明D296大孔阴离子离子交换树脂吸附锆、铪的K_d(Zr)/K_d(Hf)的值最好,好于孔径较小的D290大孔阴离子交换树脂,即离子交换树脂的孔结构对两相分配系数比值有较为显著的影响。进一步研究了硫酸锆(铪)溶液中加入硫酸的量和溶液的温度对D296大孔阴离子交换树脂吸附锆、铪的K_d(Zr)、K_d(Hf)和二者比值的影响。研究表明,控制硫酸锆(铪)溶液的吸附温度在1~3℃和硫酸锆(铪)溶液中c(H_2SO_4)为1.6mol/L条件下,D296树脂对铪的吸附量最小,K_d(Zr)/K_d(Hf)的值达到最佳。研究结果表明控制D296树脂吸附硫酸锆(铪)溶液中的K_d(Hf)到较小的值,即K_d(Zr)/K_d(Hf)的值最大,有利于后续通过进一步淋洗试验分离得到核纯级的锆和铪。     

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.     

某微细粒氰化渣浮选回收金实验研究

本试验对某微细嵌布氰化渣进行了矿石性质、金赋存状态、粒度和多元素分析,进行了浮选回收金工艺和条件实验的详细研究,最终确定采用浮选工艺,硫化矿和铁氧化矿分开浮选的工艺流程,这样有利于提高金回收率。研究结果表明采用一粗、两精、三扫、中矿精选的硫化矿、铁氧化矿分开浮选的工艺流程,获得精矿金品位31.26 g/t,回收率62.65%,相比较现场混合浮选,金精矿品位提高了约10 g/t、回收率提高了5%,对同类矿产资源的利用提供了参考依据。     

Selective flotation separation of spodumene from feldspar using new mixed anionic/cationic collectors

The selectivity in flotation separation of spodumene from other pegmatic aluminosilicates such as feldspar and mica, using a single fatty acid anionic collector, is found to be very difficult. It is attributed to the same surface Al site for interaction with fatty acid. In this study, a collector mixture of sodium oleate (NaOL) and dodecyl trimethyl ammonium chloride (DTAC) demonstrates a high selectivity for the flotation of spodumene from feldspar. The influences of important factors such as molar ratio of the mixed collectors, dosages of calcium chloride, sodium hydroxide and sodium carbonate, and pulp temperature on spodumene and feldspar flotation using the mixed collectors have been investigated through micro-flotation tests. The optimum molar ratio of NaOL and DTAC is found to be 9:1. Sodium hydroxide has to be used as a pH regulator. Without the use of depressants, no selectivity is observed as the flotation of spodumene and feldspar are activated by Ca²⁺. Sodium carbonate must be used as depressant of feldspar. A comparison of the flotation for a lithium pegmatite ore using mixed fatty acid soaps and mixed anionic/cationic collectors (NaOL/DTAC) was carried out by the batch flotation tests. The results indicated that NaOL/DTAC decrease collector consumption by two-thirds. The recovery and grade of Li₂O concentrates increase by 4.93% and 0.31%, respectively.     

氰化尾渣熔融氯化提金银试验

以氰化尾渣原料,采用熔融氯化工艺提金,研究了氯化钙添加量、氯化时间、氯化钙的添加方式等因素对氯化提金的影响,并对如何降低熔融氯化温度进行了探索。结果表明,CaCl_2添加量为7%,分五次添加,熔融氯化时间为15min。氧化钙添加量为5%,熔融氯化温度为1 450℃。金挥发率为95.69%,渣含金为0.54g/t;银挥发率为77.06%,渣含银为4.20g/t。     

Effects of free cyanide and cuprous cyanide on the flotation of gold and silver bearing pyrite

At gold and silver mineral processing plants, cyanide species are always present in the process water recycled to flotation circuits, despite the cyanide destruction process. The effect of cyanide, in particular, cuprous cyanide on gold and silver flotation has not been well understood. In the present study, free cyanide and cuprous cyanide species were isolated and their effects on the flotation of a pyritic ore were evaluated. It was found that free cyanide depressed gold and silver flotation through their carrier, pyrite. Cuprous cyanide mainly in the form of Cu(CN)₃²⁻ depressed pyrite flotation similarly as free cyanide. Electrochemical studies including open circuit potential (OCP), cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques were carried out to understand the underpinning depression mechanism of cyanide species on pyrite flotation using xanthate as collector. It was found that all surface electrochemical reactions were inhibited by either free cyanide or cuprous cyanide. The surface layer as a result of xanthate adsorption on pyrite was completely removed in the presence of these cyanide species, which was suggested to contribute to the hydrophilic pyrite surface.     

Diagnostic pre-treatment procedure for simultaneous cyanide leaching of gold and silver from a refractory gold/silver ore

This study investigates the optimization of simultaneous dissolution of gold and silver from a refractory gold ore through determination of pre-treatment stages. Based on the mineralogical studies (thin layer and polished section) and chemical analysis on the ore sample, a “diagnostic leaching” procedure was designed. Results from diagnostic leaching suggest that the most effective pre-treatment agents for gold and silver are ferric chloride and sulfuric acid media, respectively. Optimum conditions for the simultaneous dissolution of gold and silver were determined using a two factorial design technique. Pre-treatments with sulfuric acid and ferric chloride reagents increased the efficiency of the dissolution of gold from 54.7% to 82% and silver from 37.4% to 81.6%.     

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。     

Solvent extraction of gold(I) from alkaline cyanide solutions by the cetylpyridinium bromide/tributylphosphate system

This paper explores the solvent extraction of KAu(CN)₂ from alkaline cyanide solutions using quaternary ammonium cetylpyridinium bromide (CPB) as an extractant with the addition of tributylphosphate (TBP) as a modifier. It also investigates the influence of several variables on gold extraction, including the molar ratio (β) of CPB to Au(I), the volume percentage of TBP (φ_TBP), NaCl concentration, phase ratio (AQ/ORG), and gold concentration in the aqueous phase. The results indicate that nearly all of the Au(I) (>98%) was transferred from the aqueous phase into the organic phase when β = 1 and φ_TBP = 30 vol%. We also carried out experiments for treating 20 L synthetic aurocyanide solution containing 10 mg/L Au(I) with column-shaped extraction equipment. The results demonstrated the recovery of more than 94.5% of Au(I) after two successive stages of extraction, and the Au(I) concentration in the raffinate was less than 0.5 mg/L. KSCN solution was used to strip the gold-loaded organic phase, and about 90% of Au(I) could be reverse extracted into the aqueous phase when the KSCN concentration reached 3.0 mol/L. The results obtained in this paper establish that the CPB/TBP extraction system has potential for practical application in the extraction and separation of gold from alkaline aurocyanide solutions.     

Simulation study of the optimal distribution of cyanide in a gold leaching circuit

The mineral industry has been using cyanidation to recover gold from ores for more than a century; however, a systematic study of the best reactant addition strategy in a cascade of agitated leaching tanks is not available in the open literature. A phenomenological mathematical model of the gold cyanidation process, calibrated with a set of industrial data from an Australian plant, together with an economic performance index is used to analyze this problem. The simulated results show that the best compromise between the two antagonistic effects, cyanide consumption and gold recovery, which are both function of cyanide concentrations, leads to a reagent distribution that depends on the leaching and cyanide consumption kinetics, pulp feed characteristics, and economic factors such as the gold market value. For the specific studied plant, in the operating range of low cyanide consumption and fast gold dissolution, all the cyanide must be added in the first tank; however, in the operating conditions of high cyanide consumption, cyanide has to be distributed in the first, second and third tanks.     

Selective leaching of arsenic and antimony from a tetrahedrite rich complex sulphide concentrate using alkaline sulphide solution

Removal of impurity elements in copper metallurgy is one of the major problems encountered today since pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of impurity elements like antimony, arsenic, mercury and bismuth, which need to be eliminated. The present work is aimed at pre-treating a tetrahedrite rich complex sulphide concentrate by selective dissolution of the impurities, therefore, upgrading it for pyrometallurgical processing. To accomplish this, dissolution of antimony and arsenic by an alkaline sulphide lixiviant from the concentrate were investigated. The lixiviant proved selective and effective to dissolve these impurity elements from the concentrate with good recoveries. Further investigations on the factors influencing the leaching efficiency of the lixiviant were studied. The parameters considered were sulphide ion and hydroxide ion concentrations, mineral particle size, reaction temperature and leaching time. Analysis of the leach residue indicates that copper content of tetrahedrite has transformed into copper sulphides with the average chemical formula Cu_1.64S. The grade and economic value of the concentrate were improved greatly after sulphide treatment, and therefore, suitable as a feedstock for smelting. The impurities have been reduced to low levels which are tolerable in the smelting furnace and consequently reduce both the treatment and environmental problem encountered when such concentrate is processed pyrometallurgically.     

某氰化浸金尾渣中铅锌综合回收选矿试验研究

江西某氰化浸金尾渣中具有综合回收价值的金属元素主要为铅、锌,品位分别为2.25％和0.71％,尾渣中铅氧化率较高,矿物粒度细.针对该尾渣性质特点,试验研究采用"次氯酸钠预处理—铅锌优先浮选工艺"方案对铅、锌进行回收,闭路试验获得了铅品位为54.53％,锌含量为5.12％的铅精矿和锌品位为46.52％,铅含量为2.37％...     

A review of copper cyanide recovery technologies for the cyanidation of copper containing gold ores

Many gold producers are today processing gold ores containing significant amount of cyanide soluble copper. Typically, cyanide destruction is used to prevent the discharge of copper cyanide into tailings storage facilities. This imposes a significant financial cost to producers from the additional cyanide used to solubilize the copper and the cost of cyanide destruction reagents. Therefore, the recovery of copper as a valuable by-product and the recycle of cyanide to the leach circuit have the potential for significant economic and environmental benefits. This includes enabling the treatment of gold ores with even higher soluble copper. Over the years, a variety of processes have been developed or proposed to recover the copper and/or cyanide including acidification based technologies such as AVR and SART, direct electrowinning, activated carbon, ion exchange resins, solvent extraction, polychelating polymers, and membrane technologies. In this paper, these processes are critically reviewed and compared, with particular focus on the advantages and limitations, and the separation of copper from cyanide. Ultimately, there is no universal process solution and the choice is highly dependent on the nature of the stream to be treated and integration with the whole processing plant.     

对某铀矿碱浸液离子交换工艺中树脂转型有关问题的探讨

摘要:某铀矿碱(碳酸盐)浸液采用离子交换回收铀的工艺,贫树脂采用NaHCO3转型,由于转型液中ρ(NaHCO3)、ρ(Cl)高,ρ(U)较高,故难以有效利用.在对该离子交换回收铀工艺中存在的树脂转型有关问题进行探讨的基础上,提出了分段储存转型液和改变淋洗终点控制的措施.措施实施后,取得显著效果:转型液的利用率由原来的不到10％增加到20％左右,NaHCO3消耗量降低约30％.     

Modelling of gold (I) cyanide adsorption based on the properties of activated bagasse

Bagasse, the fibrous residue from sugar cane milling operation, was subjected to physical activation using CO₂ to establish its suitability as a precursor for gold adsorption, specifically for the recovery of gold from cyanide medium. Mathematical modelling, which correlates the effects of carbon properties on the adsorption behaviour, was conducted to formulate a basis for tailor making the adsorbent for this particular application. The developed model suggests carbon properties of alkali pH, high total surface area and small pore diameters are required for optimum adsorption capacity. The optimum adsorption capacity attained by the developed carbon in this study was 227% that of the test commercial activated carbon, which exhibited an adsorption of 101mg Au/g carbon. Hence this demonstrates bagasse as a promising precursor for the manufacture of activated carbon for gold cyanide adsorption.     

Prediction of cyanide recovery from silver leaching tailings with AVR using multivariable regression analysis

In this study, the tailings of the silver leaching plant, Eti Gumus AS, Turkey, containing high amounts of cyanide were tested to determine optimum recovery of cyanide, using packed columns for volatilization stage of AVR (acidification, volatilization or stripping, reneutralization). All recovery tests were performed in a pilot plant constructed using random packing with column internals and practised for mass transfer calculations. The main parametrical results of each test were measured in the laboratory and statistical analysis was performed using multivariable regression analysis. The parameters investigated were the viscosity of slurry, specific density, flow time of slurry in the funnel, air velocity, pulp density (wt%), pH, gas/liquid flow ratio (G/L), operating time, recovery rates and ambient temperature. The complex effects of the parameters were evaluated by multivariable linear regression analysis, favourable models then being corrected by using variance analysis. Verification of the predictive models to prove their practical validity and residual analysis of data were performed for preliminary treatment using the AVR process of leached tailings.