Carbonaceous Gold Research Articles

Trace Analysis of Au in Carbonaceous Gold Ores by Inductively Coupled Plasma Optical Emission Spectrometry and Mass Spectrometry

Trace Analysis of Au in Carbonaceous Gold Ores by Inductively Coupled Plasma Optical Emission Spectrometry and Mass Spectrometry

Complete gold extraction and recovery from double refractory gold ores by thiourea after bio-oxidation

Cyanidation, a conventional process to extract gold from gold ores, has been used for over 130 years in industrial mining because of the high efficiency and rate of formation of Au(CN)2− and the high recovery efficiency by adsorption of Au(CN)2− on activated carbon. However, carbonaceous refractory gold ores are not targeted because Au(CN)2− is easily adsorbed on carbonaceous matter in the ores, resulting in high recovery loss. In this study, the flotation concentrates of a carbonaceous refractory gold ores was subjected to biooxidation at 45 °C using a mixed culture containing iron-oxidizing and sulfur-oxidizing bacteria, followed by gold extraction using thiourea under strongly acidic conditions. The gold extraction efficiency reached ∼100% in 12 h without re-adsorption. Finally, the quantitative recovery of the Au(CS(NH2)2)2+ complex was confirmed by adsorption on strongly cationic exchange resin. Biooxidation reduced the amount of Fe-containing metal sulfides, which minimized the decomposition of thiourea, and the Au(CS(NH2)2)2+ complex had a low affinity toward carbonaceous matter, different to Au(CN)2−. Since the process described in this study does not require roasting to remove carbonaceous materials in pretreatment and does not use cyanide for gold extraction, it is environmentally friendly and should be considered for practical applications in carbonaceous gold ore-producing mines.

Improving gold recovery in carbonaceous gold ores using naphthalene sulphonate as a blanking agent

Naphthalene sulphonate was used as a blanking agent to treat a gold ore with an 87% preg-robbing index with the aim of improving the gold recovery during carbon-in-leach (CIL). The adsorption of naphthalene sulfonate, an anionic surfactant, was significantly higher under acid conditions: 0.51 µmol/g at pH 2.4 and 0.24 µmol/g at pH 11.3. However, conditioning the ore at the expected pH for 30 mins prior to adsorption led to a similar loading of naphthalene sulfonate regardless of the initial solution pH. The gold recovery of the ore was improved from 57% to 80% during CIL, after the ore was treated with 4.48 mM naphthalene sulfonate at pH 11.3 adjusted by 4.36 mM Ca(OH)2. The main factor, that was likely responsible for the improved gold recovery, was the passivation of the adsorption sites on the carbonaceous matter in the ore. The impact of electrostatic repulsion of Au(CN)2- was negligible due to relatively unchanged surface potential before and after naphthalene sulphonate adsorption.

Inhibition of carbonaceous matters adsorbing gold using a green and efficient chlorinating agent TCCA: Inhibition behavior, kinetics and isotherms, inhibition mechanism

Refractory carbonaceous gold ore contains carbonaceous matters that seriously interfere with gold leaching. Therefore, this paper presented an in-depth experimental investigation on the inhibition gold-adsorbing behavior using Trichloroisocyanuric acid (TCCA). Various factors affecting the inhibition were analyzed. Moreover, the kinetics and isotherms associated with the adsorption were established to describe the gold adsorption of carbonaceous matters after TCCA treatment. A variety of analytical techniques were used to clarify the inhibition mechanism. The results showed the average gold adsorption percentage of elemental carbon decreased from 89.79 % to 9.33 % at pH 3.0, TCCA volume 15.17 mL, TCCA concentration 0.104 mol·L−1, 35 ℃ and 3 h. The average adsorption percentage of humic acid decreased from 56.19 % to 3.13 % at pH 5.0, TCCA volume 5.10 mL, TCCA concentration 0.012 mol·L−1, 35 ℃ and 4.5 h. The gold-adsorption behavior of the treated elemental carbon conformed to the pseudo-second-order and Langmuir model, accompanied by an activation energy of 9.42 kJ·mol−1. And the adsorption process of the treated humic acid could be explained by the pseudo-first-order and Langmuir model with an activation energy of 40.11 kJ·mol−1. TCCA molecules and their hydrolysis products covered the elemental carbon surface, resulting in a reduction in the size of the porous structure, which further affected the number and activity of surface-active sites. Treated with TCCA, the surface area of humic acid reduced from 42.84 m2·g−1 to 9.96 m2·g−1. Furthermore, spectroscopic analysis showed that the chemical groups of humic acid were destroyed, suggesting a sharp decrease in chemisorption capability.

Enzymatic degradation of carbonaceous matter in contrasting South African refractory gold ores using cell-free spent medium from Phanerochaete chrysosporium

Two carbonaceous gold ores (ZAFB and ZAFV) underwent sequential biotreatment to expose gold and minimize preg-robbing before cyanidation. These included comparable organic carbon contents (6.0%wt in ZAFB and 4.4%wt in ZAFV) but were contrasting in the graphitic degree of the carbonaceous matter. Based on Raman spectra, the carbonaceous matter in ZAFB was more physically and chemically disordered than the ZAFV. To reduce extraneous factors, ≥ 90% of sulfides in both samples were oxidatively dissolved by the thermophilic mixed culture. Afterwards, the secondarily-formed minerals (mainly jarosite) were dissolved by oxalic acid washing. The carbonaceous matter was then treated for 15 days with a cell-free spent medium (CFSM) with lignin-degrading enzymes produced from a Phanerochaete chrysosporium culture. The enzymatic treatment reduced the carbonaceous matter content in the ZAFB by 0.73%wt from an initial value of 7.56%wt, while the ZAFV was unchanged. Raman and 3D-fluorescence analysis of the carbonaceous matter showed that the CFSM treatment was much more effective on the ZAFB sample. This indicates that the graphitic degree of the carbonaceous matter is a significant factor when applying crude enzymes derived from P. chrysosporium. The lignin-degrading enzyme treatment improved the gold extraction of ZAFB from 88% to 93%. It was found that Raman spectroscopy could serve as a handy tool for determining carbonaceous gold ores that are suitable for enzymatic treatment.

Strengthening Gold Extraction from Carbonaceous Gold Ore Based on Decarburization by Two-Stage Fluidized Oxidation Roasting

Oxidation roasting is one of the most effective methods to remove carbonaceous matter from carbonaceous gold ore. However, the consolidation of calcine is a common problem caused by a large amount of heat release during the oxidation roasting of gold ore with high carbon and sulfur content. In this study, a two-stage fluidized oxidation roasting method was developed to strengthen gold extraction. Pre-roasting was performed in a low oxygen environment for the mild combustion of carbonaceous matter, and then the pre-roasted product was subjected to secondary roasting followed by leaching. The results show that reducing the carbon content in the ore by pre-roasting can effectively lower the peak temperature inside the material. After the second-stage roasting, many cracks and pores were formed in silicates and carbonates, thus increasing the distribution of exposed gold from 28.95% to 88.01%. Finally, the extraction of gold increased from 4.55% to 86.10%. Overall, this study provides references for an efficient strategy for gold recovery from carbonaceous gold ores.

Combined leaching of Carlin-type gold deposit in Guizhou by potassium chlorate and bleaching powder

Cyanidation has been considered an effective process for extracting gold from gold-bearing ores for over 100 years. However, this process also has several disadvantages including it being toxic, inefficient, and unsuitable for leaching gold from carbonaceous gold ores containing organic and inorganic carbons. Moreover, it is not feasible for the extraction of gold from refractory gold ores , which are increasingly being used.Therefore, there is an urgent need to find an environmentally friendly and efficient leaching method to improve the extraction rate of gold from refractory gold ores. This study discusses using potassium chlorate and bleaching powder for combined leaching of refractory gold ore. Compared with other leaching methods, this method does not require the pre-oxidizing of the refractory gold ore. Moreover, the optimal reaction temperature required for the reaction is lower, thus achieving efficient and environmentally friendly leaching of refractory gold ore. To improve on the method, we used response surface methodology (RSM). RSM can quickly determine the quadratic function connection between the response value and each component and optimize the experimental settings to precisely forecast the experimental findings, saving a significant amount of time and money.This study presents a response surface approach based on a thermodynamic analysis of gold-bearing mineral oxidation to analyze the primary composite design experiment. The response surface model uses four components and three levels of potassium chlorate concentration, bleaching powder addition, reaction temperature, and reaction pH. The model gives 0.16 mol l−1 potassium chlorate, 37.5 g bleaching powder, 25 °C reaction temperature, and reaction pH of 13 as the optimal conditions for leaching gold using potassium chlorate and bleaching powder. Under these conditions, the gold leaching rate can reach 90.84%. In addition, the following parameters influence combined gold leaching in decreasing order: bleaching powder dose, reaction temperature, potassium chlorate concentration, and reaction pH.The results show that potassium chlorate and bleaching powder combined is advantageous for leaching of Carlin-type gold ore in Guizhou. It provides a high leaching rate. There is no need for pre-oxidation of gold ore. It is a simple inexpensive process that can be operated at a low optimum reaction temperature. Thus, it is a feasible method in industrial applications and provides a new way for gold leaching.

The adsorption characteristics and performance of gold onto elemental carbon extracted from refractory carbonaceous gold concentrate

Refractory carbonaceous gold concentrate contains carbonaceous matters that seriously interfere with the gold extraction process. Therefore, the in-depth experimental studies on the gold-adsorption performance of elemental carbon extracted from refractory carbonaceous gold ores is of significant importance, carried out in this article. Various factors affecting the gold adsorption process are investigated, including the variations of pH, temperature, adsorption time and initial gold concentration. Moreover, the kinetic and isotherm models associated with the adsorption process are established to describe the adsorption behavior. A variety of analytical methods, such as SEM, BET, XRD, FTIR and Raman spectroscopy were used to clarify the adsorption mechanism. The results obtained suggest that the maximum adsorption rate (99.34 ± 0.25%) can be obtained at the pH value of 3.0 at 35 ℃, when the adsorption equilibrium is reached within 10 h. The gold-adsorption behavior of the extracted elemental carbon conformed to the pseudo-first-order and Freundlich model, where the limiting step in the adsorption process is based on the surface diffusion mechanism. The adsorption process was spontaneous and endothermic, accompanied by an activation energy of 8.87 kJ·mol−1. Furthermore, the isosteric heat of adsorption increases as the amount of adsorbed gold at equilibrium increases. Significantly, the gold adsorption process is predominantly physisorption-driven associated with the pore structure, the surface defects and the active sites of the extracted elemental carbon. And XPS analysis suggested that gold was adsorbed on the elemental carbon surface in the form of Au(Ⅲ).

Accelerating the decarbonization of carbonaceous gold ore by suspension oxidation roasting towards the improvement of gold leaching efficiency

• High-efficiency decarbonization technology for carbonaceous gold ore was developed. • Greatly increased exposed gold in roasted product facilitated gold leaching. • The gold extraction increased from 4.55% to 84.83% after roasting. • The ore had a good sulfur fixation effect during the roasting process. Eliminating the gold preg-robbing effect of carbonaceous matter in carbonaceous gold ores is crucial for gold leaching. In this study, suspension oxidation roasting was proposed to accelerate the decarbonization of carbonaceous gold ore. The characteristics of oxidation reaction process and gas release were analyzed by TG-DTA-FTIR. The phase transformation and microstructure evolution of samples during roasting were analyzed by XRD, SEM and BET. The results show that the gold preg-robbing effect was eliminated after the gasification of carbonaceous matter, and the CaO generated by decomposition of carbonates can effectively capture the SO 2 . After roasting for 75 min at 650 °C in a 20% O 2 atmosphere, the total carbon removal rate reached 99.42%, the distribution of exposed gold increased from 28.85% to 77.10% and the gold leaching efficiency increased from 4.55% to 84.83%. In addition, about 70% sulfur was mainly fixed in the roasted products in the form of sulfate. Therefore, the suspension oxidation roasting process is an efficient and clean pretreatment method for carbonaceous gold ores.

Recovery and kinetics of gold and vanadium from vanadium-bearing carbonaceous gold by chlorination roasting-acid leaching

ABSTRACT The idle mining or flotation decarburization of vanadium-bearing carbonaceous gold ores polluted the environment and wasted resources. In this paper, the volatilization behavior of calcined gold and the extraction kinetics of vanadium from calcined slag were analyzed to increase the high-value utilization efficiency of double refractory gold deposits. The results showed that the high-temperature chlorination efficiency of gold increased with the increase of calcium chloride dosage. At the same time, the oxidation effect of vanadium in roasting slag is also improved, which reduces the cost of extracting vanadium from roasting slag by acid. the vanadium leaching ratio of 83.3% when the calcium chloride amount of 10%, the roasting temperature of 1000℃, the roasting time of 240min, and the airflow rate of 1L/min, and the gold volatilization rate of 89.9%. The high-temperature chlorination reaction of gold and the acid leaching reaction of vanadium from calcined slag were also controlled by the interfacial chemical reaction. The apparent activation energy of the high-temperature chlorination of gold and the acid leaching of vanadium from calcined slag is calculated to be E = 71.61kJ/mol and 40.82kJ/mol, respectively. Suggested that gold recovery from vanadium-bearing carbonaceous gold ores was achieved using chlorination heat treatment. Also, the possibility of recovering vanadium from the roasting slag was verified by acid leaching experiments.

Full-process analysis on volatilizing gold, zinc by chlorination roasting and synchronous recovery vanadium by water leaching of carbonaceous gold ore

This paper describes the chlorination roasting-water leaching process for the volatilization separation of gold, zinc and simultaneous vanadium recovery from carbonaceous gold ore. Chlorination roasting was conducted on carbonaceous gold ore. The chlorination residue and volatile precipitates were examined for textural and chemical properties. The results, and the thermodynamic calculations performed using HSC, showed that gold reacts directly with NaCl to produce AuCl for volatilization, promoting associated mineral FeS2 or C. Also, ZnS can be chlorinated to produce ZnCl for volatilization directly or indirectly. FeS2 is mainly converted into Fe2O3 and retained in the chlorination residue. Low-valent vanadium (V(III), V(IV)) primarily reacts with NaCl to form NaVO3. Under optimized conditions, roasting carbonaceous gold ore with 10 wt% NaCl at 800 ℃ yielded to 92.05% gold, 92.56% zinc and ＜5% iron volatilization, respectively. After grinding the chlorination residue to < 0.074 mm particle sizes, 85.34% vanadium was recovered by water leaching extraction at 80 ℃, 10:1 liquid–solid ratio, 500 r/min stirring speed, and 4 h extraction time. The present approach may efficiently volatilize gold, zinc, recover vanadium, and separate iron from carbonaceous gold ore.

Unraveling the dissociation mechanism of gold in carbonaceous gold ore during vacuum roasting pretreatment: Effect of pyrite

Carbonaceous refractory gold ore has been an important gold ore resource for the sustainable development of the gold industry. Solving the harmful effects of mineral-locking is the first step to increase the gold leaching rate. This study employed vacuum roasting technology in the pretreatment of carbonaceous gold ore. The dissociation efficiency and mechanism of gold in carbonaceous gold ore was investigated using a Mineral Liberation Analyser, thermogravimetric analysis, scanning electron microscopy, and X-ray diffraction analysis. The results showed that the effect of gold-locking could be effectively solved through the thermal decomposition of pyrite during vacuum roasting pretreatment. After vacuum roasting, the content of exposed and semi-exposed gold increased from 43.81% to 78.34%, and 72.37% of the gold locked by pyrite was dissociated. Pyrite was continuously desulfurized and converted into low-sulfur pyrrhotite during vacuum roasting, and desulfurization at 400–700 °C was the cause of mass loss and phase transformation of pyrite. The phase transformation of pyrite followed the change pyrite → monoclinic and hexagonal pyrrhotite → hexagonal pyrrhotite → troilite. At 600–700 °C, rapid desulfurization produced a well-developed pore structure of the pyrite particles, which loosened the connection between gold and pyrite. Above 700 °C, the aggregation of pyrrhotite particles by slow desulfurization improved separation of gold and pyrrhotite. Gold locked by pyrite in the carbonaceous gold ore was dissociated effectively under the combined action of the two stages. The high content of exposed and semi-exposed gold provided necessary conditions for the improvement of gold leaching rate in the later leaching process.

Laccase-mediator system for enzymatic degradation of carbonaceous matter in the sequential pretreatment of double refractory gold ore from Syama mine, Mali

The sequential bio-treatment of refractory carbonaceous gold ore is a promising solution to recover gold effectively by environmentally friendly technology, which includes bio-oxidation of sulfide and biodegradation of carbonaceous matter by lignin-degrading enzymes. There are several drawbacks in enzyme treatment using cell-free spent medium (CFSM), including lignin peroxidase and manganese peroxidase from Phanerochaete chrysosporium, in particular the poor stability of enzyme activities. In the present work, laccase-mediator system (LMS) was applied for the degradation of carbonaceous matter in real gold ore to improve the efficiency of gold extraction as well as handling. The LMS was intended to be a great alternative process of CFSM with utilizing purified laccase in the presence of 1-hydroxybenzotriazole as a mediator. The application of LMS provided several advantages including not only greater stability, greater efficiency to degrade carbonaceous matter, better handling, much saving the treatment time, but also wider availability in laccase. In addition, replacing bio-oxidation with ferric chloride leaching as the dissolution path of sulfides facilitated avoiding the formation of jarosite and saving the required time. The gold recovery by cyanidation was improved from 41.5 ± 0.3% for the starting material to 81.3 ± 3.9% (n = 2) for the solid residues after the modified sequential pretreatment. This is correspondent to 86.3% of gold recovery for the extractable maximum gold excluding the enclosed gold in acid-insoluble silicates. The improved process involving LMS can be proposed with valuable advantages to fit a sustainable metallurgical technology of gold ores.

Leaching of a carbonaceous gold concentrate in copper-tartrate-thiosulfate solutions

The leaching behavior of gold from a carbonaceous gold concentrate in copper-tartrate-thiosulfate solutions was studied in this paper. Experimental parameters, including temperature, initial pH, copper, tartrate, and thiosulfate concentration, were systematically investigated. The capability of leaching gold from the carbonaceous gold concentrate by copper-tartrate-thiosulfate solutions is comparable to that in cyanidation or traditional copper-ammonia-thiosulfate systems. The consumption of thiosulfate can be significantly reduced in the presence of tartrate. The mechanism of gold leaching in copper-tartrate-thiosulfate solutions is catalyzed by the mononuclear CuL2H-46− complex when the solution pH is beyond 10.5 based on thermodynamic analysis. The stability of the CuL2H-46− complex increases with an increase in the tartrate content and decreases with increasing copper and thiosulfate concentrations. A moderate increase in solution pH and temperature exhibits less effect on the consumption of thiosulfate or copper-tartrate complex, but a higher temperature may cause a sharp decline in the content of copper-tartrate complex. The recycling of the leaching solutions demonstrates that maintaining a suitable concentration of copper ions and thiosulfate and a suitable solution pH are crucial to obtain a considerable gold leaching rate.

Carbonaceous Gold Concentrates Treatment by Pressure Oxidation Enhanced by Nitric Acid Addition

Carbonaceous Gold Concentrates Treatment by Pressure Oxidation Enhanced by Nitric Acid Addition

Improvement of the leach efficiency of carbonaceous gold concentrates using reduction roasting pretreatment technology

Carbonaceous gold concentrates were pretreated using a reduction roasting method. The roasting process was investigated by thermogravimetry-mass spectrometry and X-ray diffraction. The characteristics of the thermal reaction process and gas release, and the removal mechanism for pyrite and organic carbon were analyzed. Results showed that the thermal decomposition and reduction reactions caused the highest weight loss. The main gold-locked mineral of pyrite was eliminated by decomposition and reduction reaction to produce FeS and S2. The “preg-robbing” ability of organic carbon was eliminated by thermal decomposition to converted into graphite. After reduction roasting, exposed gold content increased from 34.65% to 83.25%, organic carbon removal rate was 98.38%, and the gold leaching rate increased significantly from 2.43% to 73.7%. The technology solved the gold locking and “preg-robbing” problems of organic carbon, prevented the production of SO2, which realized a highly efficient and clean pretreatment for carbonaceous gold concentrates.

Study on Vacuum Roasting Pretreatment of Carbonaceous Gold Concentrates Based on Nonoxidation Technology

Carbonaceous gold ores are difficult to treat because of the “preg-robbing” by carbonaceous matters and locking by minerals. Roasting is the most commonly used method that is useful in dealing with carbonaceous gold ores. In this study, flotation gold concentrates containing sulfides and carbonaceous matters were investigated to ascertain the reaction process and the matters’ transformation characteristics in different temperatures by vacuum roasting pretreatment. Calcine and volatile condensates were characterized with several techniques. In the process of vacuum roasting, the main chemical reactions were decomposition reaction and carbothermic reduction reactions of sulfide ores, carbothermic reduction reactions of SiO2, and thermal decomposition reactions of organic carbon. The bad effects of “preg-robbing” by carbonaceous matters were greatly weakened by the thermal decomposition and carbothermal reduction. The gold locking minerals were mainly removed by reduction reactions. The sulfides were removed in ways that did not produce SO2. The removal of sulfur and carbonaceous matters during the vacuum roasting process was 95.83% and 65.38%, respectively. Direct cyanidation of the calcine extracted from 2.13% to 88.37% of the gold content with a vacuum degree of 10 Pa and roasting from 25°C to 1,200°C for 30 min.

Study on mechanism of carbonaceous gold ore during oxidation roasting by kinetics: phase transformation and structure evolution

The pretreatment and effective utilization of carbonaceous gold ore is of significant to refractory gold resources. In this work, the calcination kinetics was employed to investigate the relationship between phase transformation and structure evolution of carbonaceous gold ore during roasting process. Mechanism functions were determined and the fact that roasting process was controlled by chemical reaction in the initial 90 min and dominated by internal diffusion as time reached to 120 min was uncovered. In addition, the apparent activation energies for initial and latter roasting stage were 212.11 kJ·mol−1 and 163.73 kJ·mol−1, respectively. Combined with the analysis of phase transformation and structure evolution, the removal of carbonaceous matter and appearance of new tiny pores contributed to the change of calcination kinetics. Moreover, phase transformation and structure evolution were beneficial for elevating Au recovery during leaching experiment. These findings helped to understand the mechanism of carbonaceous minerals during roasting and provided new insight for the utilization of refractory gold resource.

Degradation of powder activated carbon by laccase-mediator system: Model experiments for the improvement of gold recovery from carbonaceous gold ore

Several efforts are made to find various green alternatives for carbonaceous matter (CM) degradation in carbonaceous gold ores. The deleterious effect of CM is observed during cyanidation, where CM adsorbs Au(CN)2- behaving like activated carbon, an effect called pre-robbing. Thus, biotechnological approaches like enzyme degradation of CM to reduce Au(CN)2- adsorption are currently being studied. In the present work, the potential of CM degradation and gold preg-robbing reduction by laccase-mediator system (LMS) oxidation was evaluated using powder activated carbon (PAC) as CM surrogate material through model experiments. Based upon gas chromatography-mass spectrometry (GC-MS) analysis of extracted by-products from bio-treated PAC, LMS treatment after seven days physically and chemically altered the surface of PAC by the reduction of specific surface area and pore volume, the disruption of aromatic moieties into aliphatic compounds, and the formation of oxygen-containing functional groups. Subsequently, under the studied condition, the adsorption capacity of Au(CN)2- on the surface-degraded PAC was dramatically decreased from 46 μmol/g to 7.36 μmol/g. The present findings provide a new outlook of an alternative pre-treatment process of carbonaceous gold ore in mineral processing.

Reducing preg-robbing in carbonaceous gold ores using passivative or blanking agents

Carbonaceous materials found in gold ores often exhibits strong preg-robbing properties which adversely affect gold recovery during the cyanidation due to its ability to adsorb, or preg-rob gold from the cyanide leach solution. Treatments of carbonaceous ores with chemical surfactants as blinding agents to limit preg-robbing have shown promising results however, if not properly used, could have a strong detrimental effect on the gold recovery process. The present study investigated the effectiveness of using commercially available surfactants (Dextrin, naphthalene sulphonate and Triton X-100) as blanking agents to minimize the preg-robbing capacity of various carbonaceous materials (activated carbon, anthracite and bituminous) and carbonaceous gold ore through adsorption and leaching studies. Chemical analysis of ore sample used for the study showed that the gold (Au) content was 17.2 g/t. The organic carbon content of the ore sample was 0.95%. Mineralogical composition of the ore sample determined with X-ray diffraction (XRD) showed that pyrite (24.8%), Quartz (21.5%) and Muscovite (21.8%) were the main mineral in the ore. Gold adsorption studies performed revealed that the treatment of the carbonaceous materials (activated carbon, anthracite and bituminous) with the blanking reagents significantly decrease gold adsorption by the carbonaceous materials. However, the blanking ability for the surfactant varied for the various carbonaceous materials. Application adsorption studies to gold leaching test confirmed that the three surfactants, especially naphthalene sulphonate could be used as blanking agents for carbonaceous gold ores during cyanidation. Gold recovery from CIL studies increased from 46.0% to 67.7%, 52.3% and 49.0% after treatment with naphthalene sulphonate, dextrin and triton X-100 (49.0%) respectively.