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By V. Sheikhzadeh, M. Saghaeian, R. Hejazi, A. Abazarpoor

The research aimed to compare the chemical analysis (K, Na, Cl) of Iranian concentrate plants, which are the main source of materials corrosion in the pelletizing plants. Cl alongside alkaline elements (especially K) may cause corrosion and plug in the grate plates and other involved equipment. Therefore, it is tried in the processing plants to remove impurities from the concentrate to prevent potential problems in pelletizing and iron/steel making processes. Part of these impurities are existed in the nature of ores and others are sourced in the processing water. Various samples from the largest Iranian concentrate plants including Chadormalu, Gol-e-Gohar, Jalal-Abad and Sechahun were prepared to investigate the possibility of alkaline problems for each samples. The amount of Cl, K and Na of Chadormalu sample was obviously low and therefore no alkaline problem is expected. The Cl content of Gol-e-Gohar sample was high (980 ppm) while amount of K was less (0.008 Wt. %). Due to low content of K, most of Cl will release as Cl2 or HCl and so problems caused by KCl plugging would not be a problem. The amount of Cl in Sechahun case was nearly same as Jalal-Abad (400-600 ppm), higher than Chadormalu and less than Gol-e-Gohar samples. However, the K content was higher than all samples (0.04 Wt. %). Therefore, the amount of evaporated K would be 2-4 times more than other samples. Since the amount of Cl and K is simultaneously higher than usual iron ores, therefore alkaline problems may be a serious prevention factor for the continuous operation of this plant. In order to solve this problem some counter-measures is suggested and discussed including cleaning system, partial dust enriched with KCl removal and variation in the materials type of involved equipment.

Jan 1, 2018

By Nina Panteleeva, Elena Afonina, Stanislav Titkov, Jury Buksha

"Flotation processing of water-soluble minerals (potassium ores, sedimentary salts of salt lakes) is currently the main method for production of potassium fertilizers and concentrated carnallite which is the initial product for production of metallic magnesium. Flotation of sylvite (KCl) and halite (NaCl) is carried out in the electrolyte solutions: KCl-NaCl-H2O and KCl-NaCl-MgCl2-H2O. The report presents the results of studies of the effect of concentration and the electrolyte type on the size of air bubbles in a flotation cell in comparison with the floatability of mineral constituents of potash ores. The floatability in electrolytes of various compositions has been studied: - of sylvite (KCl) by alkylamines, - of halite (NaCl) by alkylmorpholines, - of silicate-carbonate slimes contained in the ore by ethoxylated surfactants. The reagent modes (regimes) activating the flotation desliming of potash ores have been developed."

Jan 1, 2014

By L. Li

Chemical composition, mineral composition, and iron occurrence state of main mineral are studied, Research of mineral processing technology is carried out according to ore features. The test results indicate, that through staged grinding-staged concentration process, the better separation index is up to 65.54%, iron preparation concentrate grade and 85.66% recovery with the fineness (-200 mesh) 45.88% in the primary grinding ore and the fineness (-200 mesh) 75.50%, in secondary grinding ore in the situation of best magnetic field intensity (roughing 0.2T and cleaning 0.15T).

Sep 1, 2012

By Y. F. Li

Fengning ilmenite ore is a magnetic deposit in gabbro containing high phosphorus and low titanium, the main minerals in which are ilmenite, magnetite and apatite. The dissemination size of magnetite is so fine that even the percentage of -0.010mm level is up to 36.50%. The fine and vein magnetite are distributed in gangue and ilmenite, so the majority of the magnetite is difficult to be separated from the gangue. Ilmenite is difficult to be recovered by low-intensity magnetic separation even through fine grinding. In high-intensity magnetic separation of ilmenite, the gangue inter-growth with the magnetite and the Fe-containing silicates may be enriched in the concentrate, and the ilmenite of the concentrate will be reduced. Based on the processing mineralogy research, combined gravity-flotation process is suggested to recover the ilmenite. The method is also good to reduce phosphorus in the ilmenite concentrate.

Jan 1, 2014

By Sergey S. Gudkov

In the current climate of changing the approach to mining and treatment of mineral resources, processing technologies are being developed that require little maintenance and are economically as well as ecologically sustainable. This may also involve the development of entirely new ways of ore processing. One promising approach is to use bioleaching for the pretreatment of gold refractory ores to cyanidation. Capital costs for vat bioleaching of concentrates and ores are very high and cannot be applied for small or medium-size deposits. IRGIREDMET JSC carried out bio heap leaching test work on refractory ore samples from three Russian deposits. Following this biological treatment a combination of flotation, vat bioleaching, and cyanidation are used to recover gold. After heap bioleaching, gold recovery was 75-80 per cent. It was found that efficiency of heap bioleaching process depends on ore feed size. High duration of this process is another feature and it lasts for about a year. This process can be also used for carbonates in the combination with other process during which acid generation occurs. The results of our studies have shown that this technology is amenable for refractory gold ores. Its introduction allows an increase gold recovery and to solve a number of environmental problems. Keywords: heap biooxidaton, the refractory of the ores, the degree of oxidation, arsenopyrite, pyrite, CIL

Sep 1, 2012

By R. Kobialka

In the article results of experiments over jaws? linings in jaw crushers with different shaping of working surface were presented. Following sets of jaws were under investigation: immobile plain jaw and moving jaw with grooving surface. Grooving jaws have groves with circular, triangular and trapezoid cross section. In order to evaluate efficiency of comminution both the grain composition of product and the content of irregular grains were determined, as well as the size of crushing forces and process efficiency were measured. For the combination: plain jaw with grooved one, a good results were obtained as regards the grain composition of product and the content of irregular grains. Crushing forces were higher at crushing with mixed types of jaws (the one plain, the second grooved), in comparison to crushing with using both grooved jaws. Efficiency of the process was definitely higher for mixed jaws.

Jan 1, 2014

By Hakan Gürsoy, Kemal Bilir, Bahri Öteyaka, Ali Uçar, Oktay Sahbaz

"Jet diffuser flotation column (JDFC) is a flotation device resembles Jameson flotation cell (JFC) in terms of operational principles, but it has significant difference structural points of view. This difference is an essential change in the downcomer to provide an increase of performance of the cell for the coarse particles. By using the hydrodynamic and fluid mechanics principles (Sahbaz et al., 2013) downcomer was changed as a diffuser, therefore turbulence at the end of the downcomer was reduced to provide better aggregate stability and homogeneous dissipation of the bubbles in the separation tank. According to experimental results carried out in pilot scale JDFC, not only higher flotation performance comparing with Jameson cell was obtained specifically for coarse talc particles in a certain condition, but also quiescent froth layer was acquired. In these tests, vertical pipe of JDFC having inlet diameter of 6 cm and outlet diameter of 11.5 cm was used with separation tank having the diameter of 39 cm. By using the data, pilot scale JDFC having 410 cm vertical pipe integrated with separation tank was produced and flotation tests were carried out by using the naturally hydrophobic mineral (talc). Finally, the talc recovery obtained as 94% by the use of JDFC, while Jameson cell has the recovery of 77% for the particle size of 250 µm."

Jan 1, 2014

By Kilian Neubert, Wotruba. Hermann, Lars Weitkämper

Metallurgical slags are produced in large quantities all around the world as a result of smelting, refining or alloying processes applied to metals, ores and recycling material. The slag phase serves different purposes in metallurgical processes. It prevents heat losses and protects the metal phases from contaminations and absorbs gangue and extracted impurities. Due to achievable metallurgical efficiencies certain amounts of valuable metal contents always remain in the residual slag. Recycling of these metallurgical slags has several positive effects, such as optimized ecological and economical compliance of the producing industry. If recycled metal contents can be reintroduced into existing processes, required inputs of raw material can be lowered. High metal prices enable the economic recovery of metal contents in metallurgical slags by applying different non-metallurgical processing methods. Conventional processing of metallurgical slags utilizes processes such as hand picking, selective comminution, screening and magnetic separation. Those state of the art processing techniques have limitations in terms of achievable metal recoveries and required energy demand. The approach for an optimized processing of metallurgical slags targets enhanced metal recoveries in combination with lower specific treatment costs. Processes such as coarse and ultrafine density separation, as well as sensor-based sorting as a pre-concentration stage are used to enable an efficient recovery of metal contents in slags. By applying these methods a completely dry working process is possible. This paper reviews the commonly used methods and describes approaches for innovative processing of metallurgical slags to enhance metal recoveries. Focus of this paper is laid on sensor-based sorting as well as on processes for dry density separation.

Jan 1, 2014

By X. M. Chen

The selection of leach reagent mainly according to the ratio of useful mineral to gangue in mineral raw material and the structure of mineral raw material. Besides that the price of reagent, the capability of reagent decomposing mineral and its causticity on equipment is also supposed to be in regard. On common conditions, the scandium content in mineral raw material is low, even Sc concentrate of specimen-Yunnan rare earth ore which contain Sc used in this experiment only is 148 g/t. Moreover, in enlarging scale experiments the content of scandium in leach liquid is only 3.6g/t, meanwhile various and complicated impurity existing in it. At present, both domestic and abroad has succeed in enriching scandium from vitriol solution, while enriching scandium from hydrochloric acid only has been studied in some minority units, which is not reported to be practical in industry. Therefore, this item offer a new research issue on Sc?s extract, which is as well as the task of this research. Spectrum analysis, chemic component analysis and scandium content have been made in main mineral measurement on rare earth with Sc in the paper. Based on characters of sample, select hydrochloric acid, vitriol and nitric acid as leach reagent and make different blueprints to accomplish the experimental research about selecting leach reagent. In the aspect of rare earth leach scandium leach density is researched, leach liquid to solid rate, leach temperature, leach time, leach granule rate and leach solution. This experiment claims that in the optimal experimental ambience, leach rate of vitriol is 58.18%, the leach rate of nitric acid is 50.73% and the leach rate of hydrochloric acid is 59.34%. Among them, hydrochloric acid has the best effect, therefore this experiment choose it as the leach reagent.

Jan 1, 2014

By Neill Bartie, Jacques Eksteen, Sharif Jahanshahi, Shouyi Sun

The gradual increase in Cr2O3 levels of UG-2 ores has become a matter of concern for platinum producers in South Africa due to the formation of chromite spinels in melters. The effect of bulk FeOx/MgO ratio, Cr2O3, temperature and oxygen partial pressure on phase stability and composition in the system FeOx-MgOSiO2- Cr2O3-Al2O3-CaO has been studied between 1400°C and 1600°C using the drop-quench technique. An increase in temperature was found to result in a decrease in [Fe/Cr]spinel. An increase in bulk FeOx/MgO caused Mg, Al and Cr in spinel to decrease, forming more magnetite relative to other spinels. [Fe]spinel decreased and [Cr]glass increased with a decrease in oxygen partial pressure.

Jan 1, 2003

By D. Saramak

The comminution technology based on High-Pressure Grinding Rolls presses (HPGR) application is currently one of the most efficient methods of hard ore comminution from the scope of the energy consumption and the development of industrial HPGR applications in ore preparation circuits is presently the world trend. However, even though the technology is already in use in many countries, which are the leaders in application of modern mining technology, there is still lack of base investigations over the HPGR performance. Throughput and energetic models of HPGR performance are quite well developed, but technological models predicting the comminution effects still needs an in-depth research. In the paper authors present the method of modeling of HPGR products? particle size distribution with using of suitable mathematical models. A basis of the HPGR performance assessment and HPGR-based crushing circuits design is a product?s particle size distribution. In order to precisely determine the particle size distribution of a HPGR product, parameters of product?s particle size distributions should be conditional on the main technical parameters of the roller press like operating pressure and the speed of rolls. The most accurate approximation of a distribution of size particle d appeared the Weibull?s truncated distribution and it is possible to obtain significant relationships between the approximation formula and the value of operating pressure, or feed characteristics. It makes possible a determination of mass recoveries of the product?s respective size fractions and the productivity planning. Instead of pressure (P), the other HPGR operating parameters can be applied, but the P value appears to produce the most relevant relationship. Keywords: HPGR, comminution, particle size distribution, ore processing

Sep 1, 2012

By Q. Cui, Z. G. Song, S. S. Lin, S. Q. Li, S. S. Lu, G. B. Zheng, A. J. Ren

"Mine tailings is one of the most important bulk industrial solid wastes, but its rate of comprehensive utilization is relatively low. Efficient separation, recovery and utilization of the valuable components is one focus of the comprehensive utilization of tailings. Beneficiation recovery of the valuable minerals is the most direct comprehensive utilization method for tailings. There are generally different kinds of nonmetallic minerals contained in the nonferrous metal mine tailings, which are secondary mineral resources waiting for further developing and recovery. Comprehensive utilization test studies on fluorite in tungsten beneficiation tailings and feldspar in molybdenum beneficiation tailings have been carried out by author and good test results are achieved. Some of the technologies developed in the test study have been applied in industrial productions, which have been working well. The economic, social and environmental benefits are remarkable. Our test studies and some production practices will be summarized and current situation and existing problems of comprehensive utilization for nonferrous metal mine tailings will also be discussed. Assumption and prospect for the future study on comprehensive utilization of nonferrous metal mine tailings will be brought at last.INTRODUCTION Mine tailings is one of the most important bulk industrial solid wastes, but its rate of comprehensive utilization is relatively low. Efficient separation, recovery and utilization of the valuable components is one focus of the comprehensive utilization of tailings. Beneficiation recovery of the valuable minerals is the most direct comprehensive utilization method for tailings. There are generally different kinds of nonmetallic minerals contained in the nonferrous metal mine tailings, which are secondary mineral resources waiting for further developing and recovery. Comprehensive utilization of nonmetallic minerals of nonferrous metal mine tailings not only can improve the value of the ore but also reduce the stock of tailings, being the key to reduce emissions at source for exploitation of nonferrous mineral resources (Cai, Yang, 2000)."

Jan 1, 2018

By Weiran Zuo, Emmy Manlapig, Fengnian Shi

The effect of metalliferous grains on electrical comminution efficiency was investigated by comparative experiments using natural rocks and synthetic samples. The result indicated that the existence of metalliferous grains affects the breakage probability and product size distribution of electrical comminution. On average, metalliferous grains increased the breakage probability of particle in the first pulse discharge by 55% and generated finer product at the coarse end. As a result, particles with metalliferous grains exhibited higher energy efficiency than that without metalliferous grain in electrical comminution. A positive linear relation between product fineness and specific energy in electrical comminution was observed. With the assistance of numerical simulation on the electrical field distribution of ore particle, the role of metalliferous grains in electrical comminution is confirmed and the mechanism of metalliferous grains effect is elucidated. Understanding of the effect of metalliferous grains on electrical comminution is important to evaluate the feasibility of applying electrical comminution to ores with different mineral composition, and to understand the breakage behavior in electrical comminution.

Jan 1, 2014

By Saeed Farrokhpay

It is known that the grinding condition has a major effect on the beneficiation characteristics of the minerals in subsequent processing, in particular, flotation. In the flotation process, particles surface and their condition can significantly influence collector adsorption and flotation performance. For example, particle shape and its surface roughness occurred during grinding may influence flotation characteristics of a specific ore. In fact, adsorption of different cationic and anionic species on mineral surfaces can be varied depending on the selected comminution procedure. The flotation performance of sulphide minerals can be detrimentally affected by the surface oxidation. The amount of surface oxidation may reduce the hydrophobicity of the mineral and makes adsorption of collectors less selective. Improved liberation may generally result in improved flotation recovery. However, this may result in finer grinding and slimes, and consequently, reduce the overall flotation recovery. This paper discusses the effect of wet and dry grinding on copper flotation of a complex Cu-Pb-Zn ore. Industrially, wet grinding is preferred due to its higher energy efficiency and owing to downstream processing requirements. In this study, series of flotation tests were conducted,and surface analysis (XPS and ToFSIMS) were performed after wet or dry grinding at two different P80 values. Mineralogical study was also conducted to investigate the liberation of valuable minerals after grinding. A higher copper flotation recovery was found for wet grinding. However, the copper recovery was increased by further grinding in both conditions (wet and dry). The results showed a higher collector adsorption on copper mineral surfaces after wet grinding. The surface analysis also revealed that the ore is slightly more oxidized after dry grinding probably due to higher temperature during dry grinding.

Sep 1, 2012

By Yuhe Tang

High Gradient Magnetic Separator with Horizontal Magnetic Line is a new type High Gradient Magnetic Separator product. It has many specific advantages, such as water-air joint discharging technique, double pulses pulp dispersion technique, multi-magnetic gradient for collecting matrix with different diameter rods, better discharging rate with the especial matrix dispose, high separating accuracy and wide applicability. In this paper, the author makes a description of High Gradient Magnetic Separator with Horizontal Magnetic Line, and puts its emphasis on analyzing industrial production data using high gradient magnetic separator with Horizontal Magnetic Line to separate weakly magnetic minerals. It is found that as the rougher for weakly magnetic minerals separation, High Gradient Magnetic Separator with Horizontal Magnetic Line has more stable metallurgical performance and cheaper running costs than other types of High Gradient Magnetic Separator when the properties of the ore change greatly and there is in the case of embedded fine particle size distribution. Keywords: high gradient magnetic separator, self cleaning technology, horizontal magnetic line, water air discharging technique

Sep 1, 2012

By Artem Dolotov, Alexander Ter-Oranesyants, Saveliy Kaplan, Boris Axenov, Vasiliy Kovalev, Valeriy Tsyplakov, Konstantin Grigorjev, Nikolai Vorob’ev-Desyatovskii

The issues of double refractory gold ores pressure oxidation were considered. It was demonstrated that along with chloride autoclave preg-robbing which has been studied there are other negative external and intra-autoclave processes resulting in gold losses. It was found that an ingress of even low concentrations of NaCN, ferrum(II) and ferrum(III) cyanide complexes, as well as thiocyanate compounds into the autoclave leads to decrease of gold recovery during further cyanidation in a "carbon in leach" process (CIL). Admixtures depressing recovery of gold can get into the autoclave together with water in the result of industrial accidents or due to peculiarities of recirculation of industrial water used for feed pulp preparation or with quench-water used for process temperature maintenance. In contrast to a chloride preg-robbing which occurs only at pressure oxidation of double refractory gold ores, cyanide preg-robbing starts in the autoclave feeding tank (so-called «upper» preg-robbing). Possible causes of cyanide autoclave preg-robbing and requirements to the quality of water supplied to autoclaving were discussed.

Jan 1, 2014

By Marina Nicolova, Irena Spasova, Plamen Georgiev, Stoyan Groudev

Different strains of "silicate" bacteria were used to improve the quality of kaolin by different ways of treatment. All strains formed large slimy capsules consisting of exopolysaccharides and were related to different species of the genus Bacillus, mainly to B. circulans and B. mucilaginosus. It was found that even a short contact of some hours of well developed cultures of these bacteria resulted in improvement of the bending strength and the other ceramic properties of the kaolin. The improvement was connected with the action of some secreted microbial metabolites such as soluble heteropolysccharides, monosugars and organic acids. The best results were achieved by continuous cultivation of bacteria in the presence of kaolin with a high relative humidity and subjected to periodic stirring.

Jan 1, 2014

By P. S. Rao

In 1951, Tata Steel became the pioneer in Asia by setting up its first ever washery in West Bokaro Colliery. The first beneficiation plant used to produce clean coal of 19% ash with chance cone. Feed size of chance washers were -75 mm to +6 mm. The fine coal (-6 mm) were used directly. With change in technology,in 1986,chance cones were replaced by DM cyclones and coal was washed in two circuits. In the coarse circuit -13 mm to +0.5 mm coal was washed in two stages while the fine coal of -0.5 mm was treated in froth floatation cell. With further improvement in the process the higher ash raw coal was feed to produce clean coal of 13% ash. In 1998, DSM cyclones were replaced by scrolled Evolute design cyclone which has Ep of 0.020 to 0.025 ranges resulting in increase efficiency of separation. With the increase in demand of clean coal, lower seam proportion has increased in raw coal production. The washability studies of individual seams indicated large difference in the seam characteristics in terms of washability and specific gravity cut points of the individual seams. So washing all seams together had resulted in frequent change in the character of coal and warrants frequent changes in the operating parameters of the plant in which the separating efficiency comes down and ultimately resulted in yield loss initially. With increase in knowledge and experience in coal washing the solution to this problem was achieved by adopting, seam-wise washing which is enabling process engineers by keeping set point for longer periods there by to enhance the separation efficiency. Keywords: coal processing, froth floatation, steam washing

Sep 1, 2012

By C. Perez

In mineral processing plants it is important to estimate rock composition, size and grindability to improve control of the grinding process. It is well known that variation in ore grindability and size distribution directly affects mills power consumption and throughput. This paper extends a general machine vision approach for on-line estimation of rock mixture composition using color information. Our proposed rock lithological recognition method requires the following steps: division of each image into sub-images, color feature extraction using the Binary Quaternion-Moment-Preserving thresholding technique (BQMP) and support vector machines (SVM) for classification. The BQMP thresholding technique splits the image in two and chooses representatives of each half using the histogram as features. The statistical parameters of the color data can be expressed using the quaternion moments into the representatives. This method can be recursively applied to the sub-images, obtaining 5x2n features in n iterations. Once the feature vector has been computed, each vector is assigned to one of three classes using a classifier. The method was tested on a database containing 20480 sub-images (64x43 pixels) of five ore types as follows: massive sulphide (MS), disseminated sulphide (DS), net textured (NT), gabbro (G), and peridotite (P). These ore types were assigned to three grindability classes: soft (MS), medium (DS and NT) and hard (G and P). The database was divided in 2 subsets: 15360 sub-images used for training and cross validation and 5120 sub-images used for test. The classification accuracy was compared with a method previously published based on a mixture of principal components analysis (PCA) for color, and wavelet texture analysis (WTA) for texture feature extraction. WTA-PCA approach reached a 76% accuracy in test while our BQMP method reached 90% of classification accuracy using only color features. Experimental results show that our proposed method yields excellent results compared to previously published results. Keywords: rock classification, lithological classification, grindability estimation

Sep 1, 2012

By Fangming Liu

The key problems of current flowsheets and equipments are analyzed. A new steel slag's crushing flowsheet whose key equipments are the improved inertia cone crusher and inertia vibrating jaw crusher is proposed. An advanced two stage open-circuit crushing method is adopted in the flowsheet, with 90% of particle size crushing under 6mm. Using inertia vibrating technology and selective crushing principle the crushers can realize steel slag separating fully into steel and slag and with flexible transmission mechanism the crusher can be protected when iron lump is passing. The flowsheets can enhance the recovery of metal greatly, and expand the application range of tail slag and added value.

Sep 1, 2012