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A new short combined flow sheet including high intensity magnetic separation and flotation for a rare earth ore in Maoniuping deposit, China has been investigated. Massive conclusive results demonstrate, that it is critical to separate the ore by high intensity magnetic separation prior to flotation for tons of slimes and nonmagnetic gangue existing. The vital technological parameters affecting flotation have been studied in detail. Modified hydroxamic acid is an efficient collector for bastnasite flotation because of its high selectivity. Flotation results also indicate high temperature that play an unfavourable role on the recovery as well as the grade of bastnasite concentrate, when the rare earth ore is floated with modified hydroxamic acid and sodium silicate depressant. Bastnasite concentrates, averaging over 65 percent REO at an overall recovery of 82-84% is achieved by the new beneficiation technology. Keywords: bastnasite, REO, magnetic separation, flotation, chelating collector, desliming

Sep 1, 2012

By G. P. Wong

"In the Inco matte separation process, a slow-cooled converter matte is separated into three main discrete mineral phases: chalcocite (Cc), heazlewoodite (Hz) and a Cu-Ni-Fe alloy. After magnetic removal of the alloy, Cc and Hz are separated by flotation at pH>12 with diphenyl guanidine (DPG) as both collector and frother. High selectivity is achieved in rougher flotation. However, in later flotation stages such as in the middlings circuit, as oxidation takes place, Hz becomes highly floatable, resulting in a very poor separation between Cc and Hz.Starch and dextrin as Hz depressants were evaluated on the middlings circuit feed and showed no positive impact on Cc/Hz separation selectivity. Ethylene diamine tetra-acetic acid (EDTA) extraction showed the existence of abundant surface Cu and Ni ions. The use of triethylene triamine (TETA) or EDTA in flotation did not improve Cc/Hz separation selectivity. Microflotation tests were carried out on pure synthetic Cc and Hz minerals. It was found that Hz did not float in the presence of DPG. However, Hz conditioned with either copper sulfate solution or in contact with Cc floated readily in the presence of DPG. It is concluded that the major reason for Hz flotation in the middlings circuit is due to Cc oxidation releasing Cu ions that adsorb on the Hz surface making it reactive with DPG thus rendering the Hz floatable."

Jan 1, 2003

By Jan Svoboda, Toyohisa Fujita

The current status and history of innovation in magnetic methods of material treatment are reviewed. The milestones and key drivers of innovation in magnetic separation are identified, advantages of this technology in comparison to other physical methods of material manipulation are discussed and reasons for its failure to live up to its potential and expectations are indicated. Derailers that were responsible for the implementation failures are identified. The future focus in such diverse areas as mineral processing, waste treatment, recycling and biosciences is discussed and the research and development needs are outlined.

Jan 1, 2003

By Xing Yang, Zhen Peng, Guangwen Zhang, Haifeng Wang, Yaqun He

"Triboelectric separation of ilmenite ore based on the tribocharge differences between ilmenite and gangue minerals was conducted in this study. Triboelectric characteristics of ilmenite and its associated minerals were studied using polyvinyl chloride (PVC), pentatricopeptide repeats (PPR), copper, polymethyl methacrylate (PMMA), stainless steel (SS), teflon and quartz glass (QG) tribochargers in lab triboelectric unit. Results demonstrated that the ilmenite particles tribocharged positively while gangue minerals tribocharged negatively using PVC as tribocharger. The particle size also has a significant effect on tribocharge, and the -0.125+0.074 mm is the optimal size fraction of triboelectric separation. Charge-mass ratios of minerals increase with the increases of tribocharging length, but the increasing rate gradually reduce. At 1.5 m tribocharging length, charge-mass ratios of ilmenite, quartz, feldspar and mica are up to 6.07 nC/g, -6.05 nC/g, -4.30 nC/g and -4.56 nC/g, respectively. Based on the triboelectric characteristics of each mineral, triboelectric separation of ilmenite was conducted, and the grade of ilmenite ore increased from 15.47% to 28.40%. INTRODUCTION As a transition metal titanium plays an irreplaceable role in medical, aerospace and materials due to its light weight, high strength and corrosion resistance. Pure titanium dioxide is an excellent white pigment and is widely applied in industries of paint and textile. Ilmenite is the main raw material for titanium industry. For the beneficiation of ilmenite, series methods have been proposed, such as the application of dry magnetic and wet gravity separations to separate the ilmenite from the zircon and rutile. Electrostatic separation is extensively used in the beneficiation of heavy mineral sands for the recovery of rutile, zircon and ilmenite while flotation is used to separate fine ilmenite (Mehdilo et al., 2014; Fan et al., 2014). Compared with flotation and gravity separation, electrostatic separation does not consume water, and native properties of materials will not be changed and energy consumption will be reduced (Wang et al., 2014). Thus, the wide application of electrostatic separation and other dry separation methods is a trend in separation and purification industry, especially in water-scarce areas."

Jan 1, 2018

By Moris Fresko, Julia Sun, Charles C. Golembewski, Vytas Svalbonas

"A history of mill strain gaging at Metso is presented. The output of these strain-gaging programs is compared with calculated stress ranges from different finite element solutions. These comparisons expose the amount of approximation that exists in the analytical solutions, starting from geometry, and material properties, and ending with different forms of internal load models. The influence of strain gaging results on mill design and analysis practices is also discussed. While these instrumentation programs are valuable in identifying areas of high stress in mills, and locations of stress concentration factors, they are by no means extensive or comprehensive enough to verify general internal load models. The vast majority of the programs were aimed at getting additional data about potential failure points, rather than describing overall mill stress behavior. This is especially true since the more recent gaging programs have not included the difficult task of gaging the mill rotating structure interior. This paper tries to avoid the novice path of leaping to general conclusions on the basis of insufficient data."

Jan 1, 2014

By H. J. Cao

Valuable elements could be extracted by microorganism ferment fluid from bauxite, which mainly due to bacteria acid namely organic acid. And after leaching, reclaiming the remainder organic acid in leaching solution was an important procedure for bauxite leaching process. the re-searching status about organic acid reclaiming process from bauxite ore bioleaching solution was summarized. Common processes for recycling organic acid from bauxite bioleaching solution in this period and their advantages and disadvantages, research aspects which need being confirmed for the future were Indicated

Jan 1, 2014

By ?. Kostadinov

Theoretical study of the behavior of grinding medium presented by TBP (tetraballpebs) was conducted by computer modeling of the position of grinding medium at different speeds and different drum fill factor. For the modeling were used known equations of motion derived for the ball load. Algorithm was created by SolidWorks software, allowing determination of center of gravity of the load in the mill and energy for grinding. These results were compared with similar results obtained by ball grinding medium. The capabilities of both grinding media are demonstrated by graphics under the following conditions: 1.Equal dimensions of the experimental model of the mill; 2.Equal mass of the grinding loads; 3.Comparison of grinding bodies with the same number, mass and density. Keywords: simulation, behavior, grinding medium, balls, tetraballpebs

Sep 1, 2012

By C. L. Xiao

With reference to the test report carried out by Guangzhou Nonferrous Metal Research Institute in 1983, the mineral process flow sheet of Yichun Tantalum-niobium mine is determined based on the characters of ores and successful experiences in light of the problems in the existing flowsheet: The ore is desilted before crushing; the primary slime is separately treated; the staged grinding process used while the fine slime is collectedly treated with tantalum and niobium as the main recoveries and lepidolite and feldspar powder as the secondary. The flowsheet is featured by comprehensive recovery, low investment and low energy cost.

Jan 1, 2014

By Y. S. Sun, P. Gao, Y. F. Li, J. W. Yu

"Oolitic hematite ore is one of the most refractory iron ores in the world. It is not feasible to separate iron minerals from raw ore by conventional mineral processing methods. In recent years, a new technology called coal-based reduction followed by magnetic separation has been employed to produce metallic iron powder from oolitic hematite ore effectively. In order to find the nucleation mechanism, a thermodynamic analysis of the carbothermic reduction of oolitic hematite ore was conducted by the HSC 6.0 thermochemical software. The phase transition and microstructure changes during the coal-based reduction were also investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the iron oxides in the oolitic ore were reduced to metallic iron following the route of Fe2O3–Fe3O4–FeO–Fe in reduction process. The reduction reactions preferentially occur in the high activity regions to form a higher concentration of Fe elements, and then more supersaturated Fe separated out to form new phase nuclei. Under the action of homo-aggregation and principle of minimum free energy, the iron cores continuously absorbed migratory Fe around and grew into quasi-spherical iron particles embedded in slag phase. INTRODUCTION With the rapid increase of steel industry, premium grade iron ore in China has been gradually exhausted, and its supply has become bottleneck for the development of iron and steel industry (Guo et al., 2015). Therefore, it is urgent to exploit the refractory iron ores, such as oolitic hematite ore. Oolitic hematite ore is widely distributes in France, Germany, America, Canada, Pakistan, China, and among other countries (Maynard and Van Houten, 2004; Li et al., 2011). In China, the explored reserve of oolitic hematite ore is 3.72 billion tons, which accounts for approximately 1/9 of total iron ore resources of China (Gao et al, 2016). Oolitic hematite ore possesses complex composition,"

Jan 1, 2018

By M. Vasudevan

In sulfide mineral flotation, the efficiency of separation is severely affected by the presence of non-sulfide gangue minerals, such as altered silicates and serpentines. Although this is an acknowledged fact, most studies in mineral processing have focused on value minerals, and studies on gangue minerals affecting flotation performance are quite rare, and even those that do are limited in scope. This paper is an attempt to highlight the use of grade-recovery curves in studying the effects of gangue minerals. Specifically, we present the flotation response of problematic Ni and Cu ores which show highly uncharacteristic but similar grade-recovery characteristics despite the very different mineralogy and try to understand this behavior and the underlying mechanism. Finally, we propose chemical modifiers as solutions to overcome the detrimental effects of these gangue minerals and improve efficiency of flotation performance. Keywords: Non-sulfide gangue, grade-recovery, sulfide minerals, serpentines, talc, shale, slimes, spiking, modifiers

Sep 1, 2012

By M. Wierink

The lifecycle of a resource, specifically a metal, is often depicted as circle from primary production from mining to minerals processing and via manufacturing and use to disposal and recycling. When a material is recycled, it is considered as saved energy compared to producing the material from primary source. This is, however, a simplified representation. At each step of the life cycle, there are changes in the quality of the material due to different materials chemical and physical interaction, phase transformations due to diffusion, radiation etc. Due to these physical and chemical phenomena there are losses of material, which as determined by thermodynamics are not recoverable within the life cycle. This can be considered as an increase embodied energy per mass unit of substance and loss exergy from the material cycle. With low cyclic loss, the material will remain in the recycling loop for a long time, while with high cyclic loss it will disappear fast. Where you put the material determines how fast it disappears from the resource cycle. In this research paper the phenomena of quality degradation of material and idea of increase of embodied energy and exergy loss within a resource cycles is portrayed. The cyclic nature of material states and transitions and energy consequences of material quality degradation as well as the parameters affecting the length of the time scales of the material cycles are described. Currently the cyclic embedded energy and the history of material is not taken under consideration in generic life cycle assessment. This easily results into a conclusion that lifetime of product is optimized only in terms of how much energy an appliance uses during its lifetime, while ignoring the loss of embedded energy due to the effects caused by the environs the material is subjected to during the cycle. Better description of the time properties of material give us a possibility to design toward optimum lifetime of products in terms of resource efficiency. Keywords: product lifetime, material lifetime, recycling, cyclic resource efficiency, material state, material quality, exergy, embodied energy

Sep 1, 2012

By M. M. Moghaddam

Charge motion is of prime importance in the efficiency of comminution in tumbling mills. Since direct observation of charge shape and its motion in industrial mill are not possible, a combination of analytical and physical studies was used to determine charge trajectory. Software packages, which predict charge motion such as the GMT (Grinding Media Trajectory) only consider the outermost layer of charge (single ball) and ignore the interactions of grinding elements. In this research, the measured charge trajectory in a 1m-diameter mill with the transparent end, called model mill, was compared with that of the GMT. Four types of polyurethane rings were accurately machined to scale down the liners arrangements at two industrial mills. To explore various charge shapes and trajectories, the model mill was operated at 55, 70 and 85% of critical speed for five levels of mill filling (10, 15, 20, 25 and 30% by volume). The angular displacement of the toe, toe departure, shoulder and charge impact point were determined from the photographs taken from the model mill. New relationships to predict charge shape and charge impact points were introduced to modify the GMT results. The relationships were validated by the model mill using the new liner of the Sarcheshmeh copper complex SAG mill. The relative error of prediction was found to be 1.1%. The results indicated that when the lifter face angle increased from 7 to 30º, the distance between the charge impact point and the toe decreased from 52 to 31º for 25% filling. This meant increasing the probability of charge impacting the toe not the liner which favoured more efficient comminution practice. After converting AG mills to SAG mills on account of liner profile change, 31% increase in throughput (from 419 to 548 t/h) in addition to 4% decrease in the product size (from 516 to 496 µm) were realized which was a significant contribution in the plant performance improvement.

Sep 1, 2012

The status quo of ecological rehabilitation in metal mine in China and progress in the technology for ecological rehabilitation are presented, including soil reconstruction, soil improvement, plant selection. The present and future research fields are suggested: basic theory of ecological rehabilitation, operative technology of ecological rehabilitation, new technology application research and ecological rehabilitation plan, management and policy.

Jan 1, 2014

The ever increasing demand for energy and the progressive depletion of crude oil resources, have renewed interest in oil shale as an alternative fuel resource. Weathered oil shale samples were assembled from El-Nakheil phosphate mine in Quseir area, Eastern desert, Egypt. The oil shale samples were prepared and analyzed by XRD (X-ray diffraction), XRF (X-ray fluorescence spectrometry), and optical microscopic techniques. Rock-Eval pyrolysis and total organic carbon were used to study shale hydrocarbon potential. A leaching procedure using inorganic and organic acids was used to selectively dissolve the oil shale associated ash forming minerals. XRD results showed that calcite is the dominant carbonate mineral, whereas primary silicate minerals are quartz and montmorillonite. SEM (Scanning Electron Microscopy) observations indicated that the organic matter is dispersed throughout the rock matrix. The acid soluble fraction upon leaching was determined to be 37.59 and 42.74 wt% by using 5% HCl and 10% HCl, respectively. The TOC was increased from 20.78 to 29.88 and 34.09 wt% by using 5% HCl and 10% HCl, respectively. Keywords: el nakheil oil shale, characterization, xrd, xrf, sem, elemental analysis, proximate analysis, ultimate analysis, thin section, rock eval pyrolysis, acid leaching

Sep 1, 2012

By V. Dementiev

Pyrite cinders is a complex raw material, in which the valuable metals are: Au(2.04 g/t), Ag(35.0 g/t), Cu(0.38%), Zn(1.1%) and Fe(56.0%). In this case high costs for mining and ore processing are not required. The hydrometallurgical treatment of pyrite cinders using thiourea, sulfite and cyanide solutions are examined in this paper. It was found that thiourea leaching is ineffective due to high consumption of thiourea and sulfuric acid. The cyanidation on pyrite cinders was conducted. Various options of the preparation of the products for the subsequent cyanidation have been examined. The tests on cyanidation process optimization were conducted. The effectiveness of these cementation methods by metallic iron or extraction for copper recovery from water phase has been shown. Zinc precipitation can be found in the form of carbonate. In order to recover noble metals from cyanide solutions, the cementation onto zinc dust was tested. The developed technology provides for recovery at 49-56%Au, 20-25%Ag, 22.5%Cu and 50%Zn during NaCN (1.4 kg/t) and CaO (6 kg/t) consumption. The results of pilot plant testing are the basis for technical regulations in order to design a pyrite cinders treatment plant. The technology has been examined in pilot-plant conditions. In this case the recovery of 54.5%Au, 45.3%Ag, 30%Cu and 49.9%Zn was achieved to provide saleable products. Keywords: pyrite cinders, thiourea leaching

Sep 1, 2012

By M. Kargar Razi

According to the unique properties and many applications of nano gold powder, it was prepared from an acid leaching tail solution. The low value residual gold ions were existed in acid leaching tail solution in Mouteh gold mine in Iran with fellow heavy metals as pollutants (FeP2+P, Cu P2+P, and ZnP2+P). Preparation of nano gold particles is achieved by two steps. First, by addition of ammonia as separation step and second using suitable reagents for precipitation/extraction step. Conditions control includes pH, residence time, temperature, agitation, and molar ratio of reducing agents to reagents. The optimum results show that nano gold powder was prepared by temperature of 250 °C, urea to gold molar ratio of 3:1, and reduction time of 20 min. Also, heat treatment improves dispersion of nano sized gold particles. The properties of gold nano powders were evaluated by SEM, A.A, and UV- Vis spectroscopy methods. The size of prepared particles were about 80nm to 90nm.

Jan 1, 2014

By B. Aydin, G. Erturk, G. Bulut

Coal is a complex material because of its structure consisting of carbon constituents and mineral matter. Flotation is readily carried out due to hydrophobic characteristic of coal. Therefore coal flotation is the most commonly used technique for fine coal beneficiation in order to acquire clean coal separating ash forming mineral matter from carbonaceous matter. In the coal flotation, floatability of coal both depends on characteristic of coal and used flotation reagent. Frothers as a flotation reagent are used to facilitate air dispersion into fine bubbles by prevention of bubble coalescence in the pulp phase, and stabilization of flotation froths. In this study, the effects of frother types and concentrations at different pH and particle size on the coal flotation were investigated. The representative sample was taken from Zonguldak, Turkey. It contains 9.1% ash and 7313 (kcal/kg) calorific value. Pine oil, Dowfroth 250, MIBC and Isooctanol were tested as frother types. It is determined that 1.92 ppm frother concentration is sufficient to float coal, except pine oil. In mixed frother tests, it is seen that Dowfroth 250 is more effective than others. No significant difference in coal recovery was observed for flotation tests at the different pH values. The best results are obtained in size of coal (-0.1 mm) with all frothers.

Jan 1, 2014

By V. Panayotov

Slag and by-products of metallurgy bear valuable components and their processing raises an in-creasing interest. Coke and iron have to be separated and other components have to be depressed, in order to obtain sellable high quality copper concentrates. Use of classical mineral processing technologies, such as magnetic separation, sulphidization, hydrometallurgy, etc. yields copper concentrates with grade of 4%~6% Cu. Copper is lost in tailings and the whole technological cycle is low profitable. Technology proposed applies an electrochemical treatment of the industrial water entering the flotation cycle. Iron and iron compounds that do not bear Cu, coke and gangue materials are depressed during the copper flotation. Copper concentrate of grade of 9.8%~10% Cu is obtained at simultaneous increase of Ag recovery by 8%~10%. As a result company profitableness is increased. Technology proposed is easy to implement, it does not require changes in the existing technology flow-sheet, and additional investment is low. The flotation process can be aided by a specially developed system for real-time analysis of the obtained copper concentrate which allows in-time corrections in the flotation parameters and entire process control. Applied flotation schemes, technological parameters and results obtained are described.

Jan 1, 2014

By Z. A. Zhou

In Canadian oil sands processing, flotation is used to recover liberated bitumen droplets from oil sands slurries. Similar to conventional mineral flotation practice, a fundamental limitation of recovering bitumen from low grade oil sand ores is its slow and ineffective aeration of the liberated small bitumen droplets. Gas nucleation and cavitation could provide better mechanisms for accelerating bitumen-bubble attachment. A research program was undertaken to examine factors affecting spontaneous bubble nucleation on bitumen surfaces. The results demonstrate that surface hydrophobicity and existence of gas nuclei in process water play a critical role for bubble nucleation. While there are more bubbles nucleated on highly hydrophobic silanated glass surfaces than on moderately hydrophobic bitumen, bubble nucleation on clean hydrophilic glass surfaces is negligible. Heating process water up to 85 ~ 95oC (as used in commercial operation) or boiling tap water prior to gas nucleation tests is shown to remove sufficient amount of gas nuclei existing in the water, thereby drastically reducing the number of bubbles nucleated on bitumen. Enhancing gas nuclei formation in hot process water is identified as a promising strategy to improve bitumen-bubble attachment during oil sands conditioning, and hence to increase bitumen recovery from low grade ores.

Jan 1, 2014

By Mohsen Hashemzadehfini

Nowadays heap leaching has become established as a mineral processing technology for treatment of some low grade minerals such as copper, gold, and zinc, etc. Heap height, particle size, leach reagent consumption, and metal recovery are four important metallurgical parameters in a hydrometallurgical process like heap leaching. This paper investigated the effects of heap height and particle size on copper recovery as well as acid consumption. Three heap heights of 2, 4 and 6 meters and two particle size fractions of less than 25.4 mm and 50.8 mm were selected as variables in the experiments. The research results showed the inverse relation between heap height and copper recovery as well as acid consumption. Under given conditions, the copper recoveries of minus 25.4 mm ore are 78.63%, 66.27% and 52.88% higher than that of minus 50.8 mm samples for the heap heights of 2, 4, and 6 m, respectively. Both copper recovery and acid consumption increase with decreasing particle size. Keywords: heap leaching, heap height, particle size, acid consumption

Sep 1, 2012