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Search Results: 1 - 10 of 2431 matches for " refractory gold concentrate "
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Effect of Pretreatment of Sulfide Refractory Concentrate with Sodium Hypochlorite, Followed by Extraction of Gold by Pressure Cyanidation, on Gold Removal  [PDF]
Alejandro Valenzuela, Jesús L. Valenzuela, José R. Parga
Advances in Chemical Engineering and Science (ACES) , 2013, DOI: 10.4236/aces.2013.33021

The majority of the refractory gold and silver occurs in occlusion in sulphides, then precious metal dissolution is possible by first oxidizing auriferous sulfide concentrate using sodium hypochlorite-sodium-hydroxide solution followed of pressure cyanidation of the oxidized concentrate, for the extraction of precious metals. This process was conducted and evaluated under cyanide and oxygen pressure. This versatile approach offers many advantages, including low temperatures, low pressure and less costly materials of construction than conventional pressure oxidation. In this study, the effect of oxygen pressure, concentration of sodium hypochlorite, temperature, and initial pH, in precious metals recovery and As removal were evaluated using a 24 factorial design. Characterization of the ores showed that pyrite and arsenopyrite were the main minerals present on the concentrate. The best results for gold extraction were obtained with oxygen pressure of 80 psi, 10% (w/w) sodium hypochlorite, temperature of 80, at pH = 13, and a constant stirring speed of 600 rpm. These conditions allowed an approximated 60% of gold and 90% of silver extractions in 1 hr.

Bacterial Pre-oxidation of Refractory Gold Concentrate from the High Altitude Areas and Cyanidation Leaching of Gold

ZHANG Zhi-qian,LIU Sheng-ming,LI Chao,LI Hong-xu,WU Chao,

过程工程学报 , 2012,
Abstract: Bacterial pre-oxidation of refractory gold ore from the high altitude areas was studied.The removal rates of Fe,S,As and cyanidation leaching rate of Au were examined under the different conditions.And the gold concentrate,oxidizing slag,and leaching residue were analyzed by XRD and SEM.The results indicated that the removal rates of Fe,S and As were up to 85% and the leaching rate of gold was 88.09%.Feasibility of bio-oxidation pretreatment in the high altitude areas was proved.Based on the experimental results,the bacterial oxidation mechanism of gold concentrates and acid solution neutralization were analyzed briefly.The bacterial oxidation of gold concentrate occurred under cooperative direct and indirect mechanism.Removal of the arsenic and heavy metal ions of liquid phase in the form of ferric arsenate and hydroxide precipitation was the main purpose of acid solution neutralization.

Li Yaqin Xia Wei Zhong Huifang,

微生物学报 , 1996,
Abstract: 用中度嗜热菌MP30菌株氧化预处理含砷难浸金精矿回收金。该菌株在45~48℃,pH1.7~2.2和混合营养条件下,在金精矿上获得最佳生长和氧化效果。毒砂是金精矿中主要含砷矿物,砷的最终脱除取决于包裹毒砂的黄铁矿完全氧化。砷脱除后可直接氰化提金,不必再行火法冶炼。金的提取量与载金矿物(主要是黄铁矿和毒砂)氧化程度相关。强化氧化条件下,MP30能使载金硫化物矿物完全氧化分解,使金充分暴露,继而氰化提金,其提取率可达90%~98%。用这一工艺从含砷难浸金精矿中回收金是可行的。
The effect of iron and oxidizing flux addition on the fire assay of low grade pyritic refractory gold ores
Turan A.,Yucel O.
Journal of Mining and Metallurgy, Section B : Metallurgy , 2011, DOI: 10.2298/jmmb110127007t
Abstract: In this study, experiments were conducted to understand the effects of different quantities of additional iron and oxidizing flux (Na2O2) on the direct fire assay of low grade pyritic refractory gold ores instead of performing any pre-treatment like roasting before fire assay. A portion of the pyritic ore was primarily roasted using a rotary kiln to remove sulphur content for the comparison of the results obtained from direct fire assay of the pyritic ore. Then, fire assay process was performed to the roasted ore and gold and silver content in the ore was determined. Unroasted ore specimens were fused by using fluxes and PbO, which accumulates the precious metals, with various quantities of iron. Correlation between the quantity of additional iron and the recovery of gold-silver were investigated. Various quantities of Na2O2, as an oxidizing flux, were added to the smelting charge with iron additions, from which the highest gold and silver recoveries were obtained from previous experiments. From the results, it was clear that the increase in additional iron and Na2O2 quantities was the reason for the increase in the recovered amounts of lead, gold and silver during the process.
Comprehensive recovery of gold and base-metal sulfide minerals from a low-grade refractory ore
Wen-juan Li,Shuang Liu,Yong-sheng Song,Jian-kang Wen,Gui-ying Zhou,Yong Chen
- , 2016, DOI: https://doi.org/10.1007/s12613-016-1361-6
Abstract: The comprehensive recovery of small amounts of valuable minerals such as gold and base-metal sulfide minerals from a low-grade refractory ore was investigated. The following treatment strategy was applied to a sample of this ore: gold flotation–gold concentrate leaching–lead and zinc flotation from the gold concentrate leaching residue. Closed-circuit trials of gold flotation yielded a gold concentrate that assayed at 40.23 g·t?1 Au with a recovery of 86.25%. The gold concentrate leaching rate was 98.76%. Two variants of lead-zinc flotation from the residue—preferential flotation of lead and zinc and bulk flotation of lead and zinc—were tested using the middling processing method. Foam from the reflotation was returned to the lead rougher flotation or lead–zinc bulk flotation, whereas middlings from reflotation were discarded. Sulfur concentrate was a byproduct. The combined strategy of flotation, leaching, and flotation is recommended for the treatment of this kind of ore.
DYNA , 2006,
Abstract: this paper presents the answer of two different minerals, considered like refractory in the extractive process of gold, to the application of the oxidating pre-treatment using microwaves, like power plant to generate the heat of transformation of sulfides to oxides and, once applied the pre-cure, the mineral is put under the leaching with sódico cyanide, under conventional conditions, with the intention of showing the mineral effect that this process has on minerals or species that cause the refractory. the minerals coming from the mine the roble and the zancudo, which present a physical and chemical refractory, due to the associations of gold, their presentation and to consuming the cyanide mineral presence cyanide and oxygenate, multiway whose 2450 frequency is of mhz and one power of 1000 w were exposed to the microwaves within a cavity; managing to oxidize more of 90% of sulfides in a time nonsuperior to the 10 minutes. finally it was possible to be concluded from the experimental phase, that the energy microwave has a great potential in the field of the extractive metallurgy, specially in auriferous the refractory menas.
Optimal Dearsenification Parameters of Gold Sulfide Concentrate with a High As Content
Yaozhong LAN,Rose WSmith,

材料科学技术学报 , 2005,
Abstract: The gold sulfide concentrate with a high As content in Liangshan District, Sichuan Province, China, is a potentially important resource. This paper describes experiments of dearsenification of gold concentrate in a weakly reduced atmosphere in a rotary pipe furnace. The results showed that the optimal parameters were a temperature range of 650~700℃, 15%~16% CO2 of gas and a reaction time of 30~40 min. The removal rate of arsenic and sulfur was over 95% and 25%~28%, respectively. With further oxidization and roasting, residue sulfur in the roasted materials was dropped to below 4%, and the cyanide leaching recovery of gold was over 92%.
Adaptability of Gold Leaching from Different Ores in Highly Stable Alkaline Thiourea Solutions

s ZHENG Su,WANG Yun-yan,CHAI Li-yuan,ZHANG Xiao-fei,

过程工程学报 , 2005,
Abstract: In order to examine the flexibility of leaching different gold ores in alkaline thiourea system, six kinds of gold concentrates and calcines with different physical and chemical properties were chosen as objects, their chemical components and phases were analyzed, and the leaching behaviours were also investigated. The results indicated that stablizing reagents Na2SO3 and Na2SiO3 decreased the decomposition rate of alkaline thiourea solution greatly. However the stable effect of Na2SiO3 on alkaline thiourea was obviously better than that of Na2SO3 as well, and the decomposition rate of alkaline thiourea reduced from 72.5% to 33.8% with adding 0.3 mol/L Na2SiO3. K3Fe(CN)6 was the soft oxidizing reagent being suitable for alkaline thiourea system. The phases of gold ores were almost not changed before and after leaching in alkaline thiourea solution. There exist a large number of substances consuming alkali in the gold ores. During the leaching process, pH of the system dropped from 12.5 to 7.0 quickly, while the stablizing reagent Na2SiO3 could maintain pH of the system at about 12, which was propitious to the leaching process. The leaching rates of the coexisting metals in gold ores were less than 0.1% in alkaline thiourea system, which indicated that gold leaching in alkaline thiourea retained excellent selectivity. The alkaline thiourea system was suitable for leaching the pretreated oxidized gold ores in which the main phase was SiO2. The gold leaching rate reaching up to 82.68% suggests promising potential in commercial gold leaching processes.
La biolixiviación como pretratamiento de menas auríferas refractarias en matriz de sulfuros
Iglesias, N.,Carranza, F.,Palencia, I.
Revista de Metalurgia , 1998,
Abstract: In this paper the effectiveness of bacterial leaching as a pretreatment of gold ores bearing sulphide minerals is analysed. Three kinds of matrixes are studied: pyrite, arsenopyrite and copper sulphides. It is concluded that bacterial leaching is an effective pretreatment for these refractory gold-bearing ores. In the case of a pyrite matrix a direct contact between the mineral and the microorganisms is necessary. In the case of copper or/and arsenic sulphide matrix, bacterial leaching may be carried out by indirect contact mechanism with effects separation, thus allowing faster kinetics than conventional bioleaching processes. This kinetic improvement reduces operation times and so the capital and operating costs. In a future, this fact may result in the enlargement of the profitable gold ore reserves, incorporating minerals that, at present, are not considered gold ores since there is not a technology, feasible from an economic point of view, for their treatment. En este trabajo se analiza la eficacia de la biolixiviación en el pretratamiento de un conjunto de minerales auríferos en los que la refractariedad viene provocada por la presencia de sulfuros metálicos. Se estudian tres tipos de matrices: pirita, arsenopirita y sulfuros de cobre. Se concluye que la biolixiviación es un pretratamiento eficaz para estos tipos de menas refractarias de oro. En el caso de menas en matriz de pirita es necesario el contacto directo entre el sulfuro y los microorganismos. En el caso de menas en matriz de sulfuros de cobre y/o de sulfuros de arsénico, la biolixiviación puede realizarse por un mecanismo de contacto indirecto con separación de efectos, lo que permite alcanzar una cinética mucho más rápida que la de los procesos convencionales de biolixiviación. Esta mejora cinética reduce los tiempos de operación con el consecuente abaratamiento de instalaciones y coste de operación. Este hecho, en un futuro, puede significar la ampliación de las reservas tratables de menas de oro mediante la incorporación de minerales que actualmente no tienen la consideración de tales por no existir procesos tecnológicos con viabilidad económica para su tratamiento.
Development of Insulating Refractory Ramming Mass from Some Nigerian Refractory Raw Materials  [PDF]
O. A. Olasupo, J. O. Borode
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2009, DOI: 10.4236/jmmce.2009.89058
Abstract: Insulating refractory ramming mass was developed from suitable Nigerian refractory raw materials. Rammed samples from several ratios of clay, silica, mica, bentonite and calcium aluminate cement (Durax) were prepared using the American Foundrymen Society (AFS) standard rammer. They were thereafter tested for such properties as apparent porosity, volumetric firing shrinkage, cold compression strength, green compression strength, loss on ignition, thermal shock resistance and refractoriness. Results indicate that eight ramming cycles were just enough for the production of the ramming masses. Two optimal ratios obtained from the experiments have a refractoriness of 1500℃ , good compression strength and excellent thermal shock resistance. They are therefore recommended for lining of rotary furnaces and crucible furnaces for the melting of ferrous and non-ferrous alloys. It could be concluded that the ramming mass serve as a viable alternative to foreign ramming mass at the same temperature application.
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