Molybdenite Flotation Research Articles

Research on Potential Control Flotation of Molybdenite

In this paper, potential control flotation of molybdenite has been investigated which focus on the effect of pulp potential on flotation performance. Optimum flotation conditions of molybdenite are determined through tests: optimum pulp potential is 190mv~300mv, dosage of sodium sulfide is 6kg/t.The potential control flotation does not use sodium silicate which solved the problem of tailing settlement difficulties. The mechanism of potential control flotation shows that S0 is the main factor that achieves potential control flotation of molybdenite.

Floatability of chalcopyrite and molybdenite in the presence of lignosulfonates. Part II. Hallimond tube flotation

The effect of six lignosulfonates on the Hallimond tube flotation of chalcopyrite and molybdenite was studied as a function of pH, with the use of common pH modifiers (soda ash, potassium hydroxide, and lime). By comparing the flotation results with the adsorption data collected in Part I of this contribution, it becomes evident that the depression of chalcopyrite flotation takes places only when lignosulfonates adsorb on the mineral surface and, at the same time, a fraction of the xanthate collector is desorbed from the mineral surface. These two conditions are met only at high pH adjusted with lime. The depression of the natural floatability of molybdenite is relatively easy using all six lignosulfonates, but once the mineral is rendered strongly hydrophobic by the addition of an oily collector (dodecane), the depression of molybdenite by lignosulfonates is very difficult and only calcium lignosulfonates, and the highest molecular weight sodium salt, produce significant levels of depression. Overall, the results suggest that it is possible to selectively float chalcopyrite from molybdenite using lignosulfonates by depressing molybdenite. This can be achieved over a wide pH range provided that a pH modifier other than lime is used for pH control. Although the results showed that chalcopyrite flotation and molybdenite depression can be achieved under similar physicochemical conditions, further tests with real ores under industrial conditions have to be carried out with particular attention to the effect of process water quality.

Industrial use of nitrogen in flotation of molybdenite at the Sarcheshmeh copper complex

The Sarcheshmeh copper deposit contains 1 billion tonnes of ore averaging 0.7% copper and 0.025% molybdenum. It is located southeast of Iran and currently processes 41,000 t/d. Molybdenite as a by-product is recovered in two separate stages. First, a bulk copper–molybdenum concentrate is produced and in the second stage these two are separated. The recovery of molybdenite in the first and second stages is 65% and 85–90%, respectively. The yearly production of molybdenite concentrate varies between 3500 and 4000 t. Sodium sulphide is used as the depressant of the copper and iron bearing minerals which due to a rather high consumption (17.7 kg/t) constitutes one of the major cost items of the plant (i.e., 58% of total reagents cost). Nitrogen for the plant was supplied from an oxygen plant used for the smelter through a 1400 m long pipeline. After using nitrogen in the plant for a period of 21 months, the consumption of sodium sulphide was reduced from 17.7 to 14.2 kg/t at constant metallurgy. The reduction was lower than expected which was mainly due to the type of sodium sulphide used and the lack of any automatic instrument to control the depressant (sodium sulphide) dosage.

Palladium, platinum and gold distribution in porphyry Cu±Mo deposits of Russia and Mongolia

The porphyry Cu–Mo deposits in the southern Siberian craton and Northern Mongolia including subduction-, collision-, and rift-related igneous series of early Paleozoic to Mesozoic age, are all characterized by varying crustal contribution to their parent magmas and the presence of explosive breccias. Precious metal and associated element contents are reported for mineralized samples, sulphide concentrates, and chalcopyrite–molybdenite flotation concentrates from porphyry Cu±Mo intrusions of Russia (Sora, Aksug and Zhireken) and Mongolia (Erdenetiun-Obo). Average PGE contents in rocks are 17 ppb Pd and 22 ppb Pt in the Aksug deposit, 13 ppb Pd and <10 ppb (detection limit) Pt in the Sora, 14 ppb Pd and 21 ppb Pt in the Erdenetuin-Obo and 18 ppb Pd and 28 ppb Pt in the Zhireken deposit. Average gold content in rocks is 61 ppb in the Aksug deposit, 17 ppb in the Sora, 21 ppb in the Erdenetuin-Obo, and 30 ppb in the Zhireken deposit. The highest average 2.3 ppm Ag was recorded in the rocks of the Sora deposit. In general, the precious metal distribution in the studied deposits has no apparent relationship with the alteration types. The molybdenum content in rocks ranges between <1 and 128 ppm Mo in the Aksug deposit, from <1 to 5400 ppm Mo in the Sora deposit, from 2 to 755 ppm Mo in the Erdenetuin-Obo deposit, and from 3 to 1530 ppm Mo in the Zhireken deposit. The average copper content in rocks is 1540 ppm in the Aksug deposit, 460 ppm in the Sora deposit, 1460 ppm in the Erdenetuin-Obo deposit, and 220 ppm in the Zhireken deposit. The Cu–Mo ratios are highest in the Aksug and Erdenetuin-Obo deposits and lowest in the Sora and Zhireken deposits. The correlation matrix for selected major and trace element data on mineralized samples and sulphide concentrates (34 samples) indicates that precious metals are associated with either chalcopyrite or molybdenite. Copper shows a strong positive correlation with Au and Pd ( r≥+0.91) while Mo shows a strong positive correlation with Pt ( r=+0.98). In addition, Mo exhibits a strong positive correlation with W ( r=+0.94). An interelement positive correlation between precious metals is 0.57 (Ag–Au). The Pd and Pt contents of both chalcopyrite and molybdenite in flotation concentrates are low, varying from 9 to 83 ppb Pd and from <10 to 110 ppb Pt. The highest values recorded are 924 ppb Pd in sulphide concentrates from the Aksug deposit, and 684 ppb Pd and 299 ppb Pt in sulphide concentrate from breccia of the Zhireken deposit. The highest gold content, 5450 ppb Au, is in chalcopyrite flotation concentrate from the Aksug deposit, whereas in the majority of concentrates the gold content is in the order of a few hundreds parts per billion. The relatively low contents and limited variation of the precious metal contents in the individual deposits of Russia and Mongolia point to the essential role of the composition of the source and composition of parent magmas.

Comparative study on the selective chalcopyrite bioleaching of a molybdenite concentrate with mesophilic and thermophilic bacteria

This study evaluates different bioleaching treatments of a molybdenite concentrate using mesophilic and thermophilic bacterial cultures. Further studies on the chemical leaching and the electrochemical behavior of the MoS 2 concentrate were carried out. Bioleaching tests showed a progressive removal of chalcopyrite from the molybdenite concentrate with an increase in temperature. Chemical leaching tests support the idea of an indirect attack of the concentrate. Electrochemical tests indicate that chalcopyrite dissolution is favored when molybdenite is present. Therefore, this type of bioleaching treatment could be applied to purify molybdenite flotation concentrates by selectively dissolving chalcopyrite.

Copper removal from molybdenite concentrate by sodium dichromate leaching

Molybdenite flotation concentrate was leached with sodium dichromate–sulfuric acid solutions in order to remove the copper sulfide impurities. The experimental results indicated that the temperature has a large influence on the copper dissolution. The concentration of dichromate has also a pronounced effect for concentrations under 0.10 M, while sulfuric acid concentration over the stoichiometric value has a deleterious effect on the copper dissolution. The purification of molybdenite concentrates by this method is feasible, and the best results were obtained by leaching the concentrate with the stoichiometric concentration of H 2SO 4 and 0.12 M Na 2Cr 2O 7 solution for 90 min at 100°C. Under these conditions, about 95% of the copper was dissolved with little dissolution of molybdenum. The kinetic study showed that the dissolution of copper from the concentrate is well represented by a shrinking core model controlled by diffusion through a porous layer, 1/3 ln(1− α)−[1−(1− α) −1/3]= k t. The apparent activation energy obtained was 40 kJ/mol for the temperature range 50 to 100°C.

Molybdenite flotation from copper/molybdenum concentrates by ozone conditioning

Typically, rougher molybdenite flotation and recovery from bulk copper/molybdenum concentrates involves the use of alkalisulfides, Nokes reagents, cyanides, oxidants, and/or thermal treatment to depress copper sulfide minerals. The bulk copper/molybdenum feed generally varies from 0.2% Mo to 1.0% Mo, and with traditional reagents the single-stage rougher flotation recovery of molybdenite varies between 40% and 90% at a concentrate grade of 5% to 10% Mo. With ozone conditioning for copper depression, however, improved separations appear to be possible, as demonstrated by tests with CulMo concentrates from both the Phelps Dodge Morenci Operations and the Kennecott Copperton Operations. Single-stage rougher flotation after ozone conditioning can provide a molybdenum concentrate at a recovery of more than 90% and a rougher concentrate grade higher than 20% Mo in some cases. Subsequent cleaner flotation with additional ozone conditioning results in relatively copper-free molybdenum concentrates containing as much as 52% Mo. Preliminary analysis indicates that, with a multistage ozone conditioning/flotation strategy, the process is technically and economically viable and should be suitable for industrial application.

Evaluation of collectors for molybdenite flotation

The empirical relationship between molybdenite recovery and collector chemical structure was developed. This information can be used for screening collectors for the molybdenite flotation system at a minimal cost.

Magma San Manuel molybdenite recovery circuit — an operational review

The molybdenite flotation plant at the Magma Copper Co. San Manuel concentrator has been in operation since 1956. In January of 1980, the plant was converted from a hydrogen peroxide-ferrocyanide process to the current sodium cyanide-sodium hydrosulfide process. This paper is an operational review of Magma Copper Co.’s molybdenite recovery circuit, column cell flotation experience, and use of on-stream X-ray fluorescence analysis.

Relationship of petroleum hydrocarbon characteristics and molybdenite flotation

Experiences in AMAX plants and laboratories have shown that petroleum hydrocarbons differ in their effectiveness for enhancing the natural floatability of molybdenite. A research program was carried out to identify the characteristics of a petroleum hydrocarbon which make it suitable as an oily collector for molybdenite flotation. To provide a systematic set of flotation oils commercial refinery base stocks were blended with diesel fuel. The effects on molybdenite flotation of the following properties of the blended oils were investigated: average molecular weight, kinematic viscosity, molecular structure, density, and weight fraction of base stock in the blend. Standard laboratory batch-flotation tests were conducted using 40 different blended oil collectors. These data were compared with the molybdenite flotation results obtained with the Amoco and Texaco oils regularly used at the AMAX plants and the test results correlated by step-wise multiple-regression analysis. The experimental evidence indicates that a two-component blend of a higher molecular-weight base stock and a lower molecular-weight diluent oil can be a better molybdenite collector than a single-component oil. Furthermore, the flotation oils blended from naphthenic base stock gave superior flotation results whereas those blended from aromatic stock resulted in inferior molybdenite flotation.

Factors affecting the flotation recovery of molybdenite from porphyry copper ores

Investigations have been conducted to characterize the surface chemical and flotation properties of molybdenite in aqueous environments typical of those that exist in the copper circuits of plants which process porphyry copper ores. These investigations have revealed that molybdenite and quartz particles are negatively charged at the pH commonly used for bulk sulfide flotation, namely 11. While the adsorption of calcium ions reduces the magnitude of negative charge on molybdenite, the adsorption can reverse the surface charge on quartz particles when the calcium concentration in solution exceeds 1 × 10 −3 M. Heterocoagulation of molybdenite and quartz particles will thus be inevitable in solutions containing large amounts of lime and will impair the floatability of molybdenite. The deleterious effects of heterocoagulation can be somewhat overcome by an ultrasonic conditioning prior to flotation. Besides heterocoagulation, particle size is very critical for optimum molybdenite flotation. Coarse molybdenite particles (120 × 200 mesh) float extremely rapidly and completely without being influenced by heterocoagulation. The flotation of fine molybdenite particles (minus 200 mesh) is sensitive to particle size and heterocoagulation. Results of tests conducted to assess the effects of overgrinding of molybdenite have indicated that while there is no change in the crystal structure due to prolonged grinding, the floatability is significantly reduced due to the creation of very rough surfaces.

The effect of dextrin on surface properties and the flotation of molybdenite

The effect of dextrin on molybdenite surface properties has been investigated experimentally through measurements of zeta potentials, adsorption densities, contact angles, Hallimond tube flotation and oil flotation response. These studies indicate that the adsorption of dextrin on molybdenite occurs through physical interaction with the surface, possibly due to hydrophobic bonding. The hydrophobic bonding mechanism is in accord with the magnitude of the adsorption free energy, which was estimated to be—5.4 kcal per mole of dextrin monomers. Dextrin was found to be a very effective depressant for the air flotation of molybdenite in the absence of a collector, whereas it does not effectively depress molybdenite in an oil flotation process using iso-octane. This has been discussed qualitatively from the contributions of electrical double layer repulsion, van der Waals' attraction, and hydration effects.

The role of surfactants in the flotation of molybdenite at climax

AbstractThe use of petroleum hydrocarbon as a collector for molybdenum sulfide improved metal recovery but necessitated the investigation of surfactants to produce a suitable froth for flotation at the Climax, Colorado mill of American Metal Climax, Inc. Up to December, 1958, 346 surfactants had been tested and evaluated. A sulfated monoglyceride of coconut oil is presently employed at Climax. The study of the role of surfactants for molybdenum sulfide flotation is continuing. One of the better materials evaluated in the last 10 years is ethoxylated, esterified and neutralized lauryl alcohol. Longer and shorter chain alcohols ethoxylated, esterified and neutralized have also been evaluated with encouraging results. Adsorption of iron hydrated complexes on molybdenite occurs which results in increased wettability of the molybdenite, an effect to strongly link the molybdenite to the water phase and reduce separability. Adsorption of ionic iron on montmorillonite and other clays occurs which activates the clays for adsorption onto the molybdenite particles. In fact, a cocoon‐like coating has been found to surround molybdenite particles. This coating being highly water wettable, prevents particles of molybdenite from responding to flotation. Depression of molybdenite particulates may be caused by a “failure to collect” which is a descriptive term indicating the lack of a colector reaction at the molybdenite surfaces. For example, iron ionic complexes adsorbed at the molybdenite surface may not be reactive with the collector or the iron ions could reduce the collector concentrating by reaction in the fluid phase. Certain of the iron complexes upon adsorption onto the molybdenite may react on highly hydrated surfaces, firmly linking the particulates to the water phase. Actually, the depression of molybdenite is incompletely understood, but it is known that hydrated ionic complexes of ferrous and ferric iron are surface‐active on molybdenite. In excessive concentrations these ions could be depressive. On the other hand, limited concentration of these ions could serve as activating ions.

Flotation of molybdenite with various oil refinery fractions

AbstractLaboratory flotation experiments were done with various oil refinery fractions to assess their relative performances as collectors of molybdenite from a British Columbia ore.The recoveries obtained with high-viscosity oils, such as Carnea 21, Sunray DX Vapor Oil and Texaco No. 539, were 2 to 4 per cent higher than those obtained with low-viscosity oils, such as stove oil, Shell Dieseline and light furnace oil. The rougher concentrate grades obtained with the high-viscosity oils were 8 to 10 per cent MoS2 and those obtained ,with the low-viscosity oils were 12 to 16 per cent MoS2. Recoveries and concentrate grades obtained with 50:50 mixtures of very high viscosity oils (such as Shell 90/ 120 LVI pale and Shell 150/210 HVI bright stock) with light furnace oil, were better than those obtained with the high-viscosity oils.The frothing agents were pine oil and Arctic Syntex L. In the presence of the low-viscosity oils, the froths were shallow and dry. In the presence of the high-viscosity oils they we...

Flotation of molybdenite with various oil refinery fractions

Laboratory flotation experiments were done with various oil refinery fractions to assess their relative performances as collectors of molybdenite from a British Columbia ore.The recoveries obtained with high-viscosity oils, such as Carnea 21, Sunray DX Vapor Oil and Texaco No. 539, were 2 to 4 per cent higher than those obtained with low-viscosity oils, such as stove oil, Shell Dieseline and light furnace oil. The rougher concentrate grades obtained with the high-viscosity oils were 8 to 10 per cent MoS2 and those obtained ,with the low-viscosity oils were 12 to 16 per cent MoS2. Recoveries and concentrate grades obtained with 50:50 mixtures of very high viscosity oils (such as Shell 90/ 120 LVI pale and Shell 150/210 HVI bright stock) with light furnace oil, were better than those obtained with the high-viscosity oils.The frothing agents were pine oil and Arctic Syntex L. In the presence of the low-viscosity oils, the froths were shallow and dry. In the presence of the high-viscosity oils they were deeper and wet, and carried more slimes. Thus the concentrate weights and drawn froth volumes were influenced by the type of collector oil used. The relationship between concentrate weight and drawn froth volume was linear. Résumé Des essais que l'auteur a faits en laboratoire ont précisé la valeur relative d'huiles de raffinerie agissant comme collecteurs de molybdénite renfermée dans un minerai de la Colombie-Britannique.Les huiles de grande viscosité, telles la Carnea 21, la Sunray DX Vapor Oil, et la Texaco no. 539, donnent des recouvrements supérieurs, par 2 à 4 p. cent, à ceux d'huiles de faible viscosité, telles l'huile à poêle, la Shell Dieseline et l'huile légère pour brûleur. Les concentrés bruts retirés par les huiles de grande viscosité renfermaient 8 à l0 p. cent de MoS2 tan dis que ceux retirés par les huiles de faible viscosité renfermaient 12 à 16 p. cent de MoS2. Les recouvrements et les teneurs des concentrés retirés par des mélanges à parts égales d'huiles très visqueuses (Shell 90/ 120 LVI pale, Shell 150/210 VHI Bright stock) et d'huile légère à brûleur sont meilleurs que dans le cas où seule l'huile très visqueuse est utilisée.Les agents moussants Artie Syntex L et l'huile de pin ont servi au cours des essais. En présence des huiles de faible viscosité, les écumes étaient minces et séches. Par contre, en présence d'huiles de grande viscosité, elles étaient épaisses et humides, et elles portaient plus de schlamms. Evidemment les huiles agissant comme agent collecteur influent sur le poids des concentres et le volume des écumes. Il y avait relation linéaire entre le poids du concentré et le volume d'écume.

Flotation of Molybdenite

Flotation of Molybdenite