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By C. Y. Sun

Flotation of chalcopyrite and unactivated malachite with xanthates (ethylxanthate, butylxanthate, octylxanthate and dodecylxanthate) is studied in this paper. Minerals interacted with xanthates are detected by FTIR, and simulated by molecular mechanics. It shows that chalcopyrite can be floated with 4 kinds of xanthates, and unactivated malachite can?t be floated with ethylxanthate but can be floated directly with later 3 kinds of xanthates while characteristic absorption peaks of those four kinds of xanthates are all detected by FTIR on chalcopyrite and malachite surface. After simulating the interaction between xanthate and mineral, it shows that H2O and OH-can interact with chalcopyrite and malachite, and their interaction energy may be so called energy bulwark which must be overcome by collector when collector interacts on minerals; the two sulfur atoms in xanthate group interact with copper and neighbor iron atoms on chalcopyrite. It also shows that molecular mechanics results with logP of collectors can interpret the mechanism of xanthate-mineral on atom scale.

Jan 1, 2014

By Hamid-Reza Manouchehri

"Sustainability calls for maintenance, rational use and enhancement of natural resources as well as balance consideration of ecology, economy, and social justice. The challenges in mining industry call for a sustained global effort using the leverage of available technologies and emerging new technologies. The industry uses significant amount of energy with the highest portion in comminution. To conserve energy, attempts have been made to improve the efficiency of the conventional crushing and grinding equipment. Nevertheless, the new and energy efficient comminution technologies are favorable through a longer term strategy. Since crushers are more energy efficient than mills, it is logic to conduct part of milling, in the crushing stage. After years of research and development, Sandvik introduces a new crushing technology, VibroconeTM, to change traditional crushing concepts. The new crushing device is able to crush and grind particles with a higher reduction ratio, more than two fold, than that of conventional crushers. By implementation of the new technology, a suitable feed size for milling can be provided to conserve energy as well as media and liner consumption, to reduce milling circulating load or increase mill capacity. There are other benefits associated with this machine, one of them being providing a higher surface area. This paper discusses the performance of the machine and its applications for comminuting different ores."

Jan 1, 2014

By W. S. Eu

Reduction of weathered mineral ores can initiate phase transformation which can affect either their activation or deactivation, subsequently influencing the extent of extraction of desired metals in a leaching reagent. The reduction of ilmenite ores for one occurs as a series of parallel, solid state reactions which at present has no known mechanisms, although the evidence of their effects is abundant. Understanding these reactions may well be the key to uncovering the mechanism of ilmenite activation, hence enabling precise control of its reaction process to maximize yield of TiO2 extraction. However, documenting the solid state reactions in the reduction of ilmenite is challenging due to the ore complexity, the number of simultaneous reactions and the difficulty of capturing critical intermediate reactions and phase transformations during processing. The phase transformations of ilmenite minerals reduced at temperatures up to 850°C were investigated in this study. Mineral transformations were studied in-situ using synchrotron radiation based X-ray powder diffraction with temperature resolved tests. The effect of the extent of reduction and specific mineral transformations were verified by leaching reduced ore with sulphuric acid. The re-sults suggest that transformation of major mineral phases occurs within of specific window of operation and thermal treatment appears to influence the extent of activation and leachability of ilmenite minerals.

Jan 1, 2014

By A. Bastrzyk

Text The mining and refining of minerals generates large amounts of solid waste. The waste from cleaning operations constitutes up to 90% of the total production. Although some of them can be used in mining, civil enegineering, construction, agriculture, most of them must be disposed in dumps and slurry ponds, causing major economic and enviromental problems (Alonso, 2002; Alon-so, 1999). The refuse from minerals cleaning may have considerable valuable particles content, which can be used in industry. Thus, the recovery of these particles from minerals waste by using a cleaning method effective at fine particle size, may overcome these consequences. Surfactants are used in numerous applications including emulsification and solid surface modification. In the oil agglomeration of minerals, the ionic surfactants (both anionic and cationic) are used for the hydrophobization of mineral surface and the oil-water emulsion preparation. When the cationic surfactant is injected into the oil-water mixture, surfactant molecules adsorb at the oil-water interface, changing droplets? properties. The addition of anionic surfactant to the mineral suspension was found to modify the solid-liquid interface. In this paper, the condition and mechanism of selective separation of magnesite from quartz are presented. A satisfactory was achieved with the amount of anionic collector (sodium oleate) equal to 15.2 mg/gsolid and with the amount of cationic collector 27.9 mg/gsolid for cetyltrimethylammonium bromide (CTAB) and 16.9 mg/gsolid for dodecyloammonium hydrochloride (DDAHCl) at pH 8. At these conditions, the amount of agglomerated carbonates was about 12% for CTAB and 5% for DDAHCl.

Jan 1, 2014

By Valentine Chanturiya1

We have developed a classification of geochemical barriers according to their origin, i.e. natural and artificial, and according to methods and areas of application. There has been an examination of the interaction between different classes of geochemical barriers with sulfate solutions containing nickel, copper and iron. As natural barriers, carbonates (calcite and dolomites) were used. For artificial barriers, a mixture of serpentine and carbonatite, thermo-activated copper-nickel dressing tailings, and a magnesium-containing sorbent based on brucite was used. Keywords: geochemical barriers, physical-chemical geotechnologies, treatment of natural and waste water, recovery of nonferrous metals

Sep 1, 2012

By Genrich A. Denisov

Principles of ecologically friendly geo-technologies construction are formulated on the basis of the works of the leading scientists in the field of rational processing of mineral resources of the Russian Academy of Sciences. One of these concepts is a new direction in rotational disintegration of mineral and technogenic raw material with the purpose of effective subsequent enrichment. A large amount of practical experience has been accumulated in the industry on selective destruction by application of vibrational method on initial material with consideration of its physical-mechanical properties and mineral structure. This method is successfully realised in a conic inertial pulverisation devices constructed by Mekhanobr Institute (St. Petersburg). A new construction of conical-inertial pulverisation with a modification of disintegration force has been developed recently at Mekhanobr Institute. It allows, in some cases, to increase selectivity of subdivision and to avoid over-disintegration. Advantages of “wet” subdivision methods in conic inertial disintegration devices are proved. The efficiency of such subdivision can be increased due to rational use of the phenomenon of a dislocation-dynamic diffusion. Its advantage is proved by the effect on disintegrated material by frequency-modulated variable electrical fields of low power. It was shown in industrial conditions, that the productivity of the spherical mill can be increased by 10 %, and that it also prevents ecologically harmful surface active substances (SAS) in milling zone and it reduces the dust content in the air. The techniques of tentative estimation of efficiency of various proceedings technogenic materials and their classification are created. The scientific fundaments of rational, ecologically friendly technology of processing and regeneration of various kinds of technogenic raw material are developed. A number of effective technologies on processing of wastes is developed and inculcated in concentration factories and metallurgical factories.

Jan 1, 2003

By Rebecca Hope, Derick Moolman, Frikkie Malan

"Despite the lip service that has been paid to pro-active plant maintenance processes over recent years, a significant portion of maintenance in industry is still reactive. The business driving force to prevent expensive production opportunity costs arising from “break-down maintenance” is obvious. Various benefits can be derived from successfully deploying remote equipment diagnosis technology and associated business processes.From an end-client’s viewpoint these include the ability to predict and take actions to prevent equipment breakdowns, increasing the lifetime of equipment by responding to appropriate operating instructions and therefore improving the return on capital expenditure. Better planning and scheduling of maintenance priorities and resources with performance measures like an Equipment Health Index are also possible. The knowledge that a qualified supplier engineer is constantly in touch with the operating conditions of their equipment, albeit remotely, is more than a comfort, and can be translated into quantifiable cost savings and improved supplier service levels.This paper analyses the reasons for the inadequate level of pro-active plant maintenance practice in industry today, and presents a number of important criteria in selecting appropriate solutions to this problem. A case study of a specific real-time, remote equipment management application is presented."

Jan 1, 2003

By Jens Markowski

The EU Directive 2000/53/EC on end-of life vehicles (ELVs) states that in 2015 at least 85 wt.-% of a vehicle has to be reused or recycled. This result in the obligatory need to separate additionally metallic and other components of the automotive shredder residues (ASR), so that they can be professionally prepared for recycling and reuse further. Currently the iron-containing fines of ASR are deposited as it is not possible to process in blast furnaces due to its particle size (< 4 mm), composition and material properties. Additionally problems are also caused in handling and transportation (dust) of the material. This work focuses mainly on the ASR materials utilization in blast furnaces. Material was further separated into two consecutive fractions by carrying out repeated crushing and magnetic separation twice. The two fractions have significantly higher iron content (up to 75 wt.-%) compared to the initial material mixture. The materials were assessed for their usage in blast furnaces based on the possible pelletisation with and without binders, stability of pellets, shape and size of pellets, etc. Pelletisation of the material was carried out with a single mould pellet press. Further lignite coal was added to the mixture as additive which improved the pelletisation behavior and the mechanical stability of pellets. Lignite coal was chosen as a reducing agent in the blast furnace process contributing towards additional savings in energy supplied. The experiments reveal that the production of pellets from iron-containing fines is possible with a lignite coal admixture of about 15 wt.-%. These pellets displayed good mechanical stability and can be used in blast furnace processes in recovery of the recyclable metals which are currently not recycled. The recycling of not yet recyclable metals would reduce the deposition and can be easily adopted into the economic cycle by their utilization. Keywords: Automotive shredder residue (ASR), FE-fines, pelletisation

Sep 1, 2012

By D. Saramak

Investigations over the application of hybrid comminution circuits with the High-Pressure Grinding Rolls (HPGR), on the main comminution stage on the basis of the lime and cement industry, were presented in the paper. Two crushing circuits were investigated, the first HPGR-based and the other one, with conventional jaw crusher. The results presented in the article confirm that hybrid comminution circuits with the application of HPGR are innovative ones, and they assure achieving the technological and economic competitiveness in the mineral raw materials processing industry. They are much more favorable in terms of the final product fineness and capacity but insignificantly less effective about the unit energy consumption. Technological performance of conventional crushing circuit and HPGR-based one were also compared in lab scale. The circuit with HPGR application gives finer products both on crushing and grinding stages. The average particle size reduction obtained in HPGR-based circuit is as much as twice greater, comparing to the conventional crushing devices. Keywords: comminution, HPGR technology

Sep 1, 2012

By Robinson Irarrazabal, Edison Collinao, Rodrigo de Carvalho, Patricio Davila, Marcelo Tavares

"In recent years, DEM (discrete element method) softwares, along with 3D laser measuring equipment, have become powerful tools to describe mill charge behavior, as well as forces acting on the liners of SAG mills. With the aim of contributing to streamline this application of the advanced technologies ME Elecmetal and Universidade Federal do Rio de Janeiro, UFRJ, proposed a new approach to improve the design of mill liners using elements from mechanistic modeling of grinding. The paper presents a methodology for continuous improvement of liner design, which uses information from the DEM collision energy spectra in the mill discriminated for the different components (ore and steel balls), as well as information on the breakage properties of the ore being ground. From these it proposes the concept of "effective collisions", which corresponds to the collisions that are of sufficient magnitude to cause breakage, thus allowing to discriminate from impacts that do not cause breakage either in a first impact or after repeated loading. It also tracks the collision of steel balls against the shell in order to assess their potential damage to the liners. An industrial case study is presented of a 38’ diameter SAG mill, which was experiencing challenges associated to liner breakage and low efficiency with the old liner design. Through a modification of the liner design, simulations demonstrated the potential benefit associated to reduction in ultraprojection and improvement in mill capacity. Implementation of the new design in the SAG mill was carried out, resulting in increase in daily throughput from 6 to 12%. Further, the time spent in liner change was reduced by 47% given the reduction in the numbers of parts. This operation also benefited from having no stops due to unplanned shutdowns to replace broken tiles. These demonstrate the benefit of coupling advanced computational tools to sound engineering principles in continuous improvement of liners."

Jan 1, 2014

By Matt Kilburn, Liming Lu, Steve Suthers, Alexander Edenton, Rodney Smyth, Matt Adam

"Magnetite concentrate is naturally good for pelletising. However, due to the depletion of reserves of traditional high grade hematite iron ore worldwide, the usage of magnetite concentrate in sintering is expected to increase substantially. Magnetite concentrate is typically high in Fe grade and releases extra heat when oxidised to hematite. This will not only improve the quality of agglomerates produced, but also have a potential beneficial impact on the fuel consumption of the agglomeration process. There are an increasing number of magnetite projects currently being considered and developed. However the concentrates from some of these projects are too coarse as pellet feeds and much finer and denser than normal sinter feeds. Accordingly, special strategies are required in order to utilise the coarse magnetite concentrates at high proportions in pelletising and sintering. This paper discusses various raw material preparation technologies and blending optimization methods demonstrated to be effective for improving the sintering and pelletising performance of coarse magnetite concentrates. Pre-granulation and addition of binders, such as hydrated lime, were found to be particularly efficient in recovering the sintering productivity of sinter blends containing magnetite concentrates. In pelletising, HPGR (High Pressure Grinding Rolls) grinding enabled production of good quality pellets from 100% magnetite concentrates and optimized blends containing up to 70% magnetite concentrates also formed good pellets.INTRODUCTION Magnetite concentrates are often used as feed materials for pellet plants or sinter plants depending on their grades and grain sizes. To achieve the required quality of green and fired pellets, the concentrates often need to be ground very fine (80% passing 38- 45 m), which inevitably consumes a great amount of energy. Therefore, efficient grinding processes are required to reduce the amount of energy consumption needed to achieve the sizing and chemical specification of pellet feeds. The use of magnetite concentrates in sintering has the potential to improve sinter chemistry, which is deteriorating over time due to the slowly decreasing grade of direct shipping iron ores around the world (Yang and Mathews, 1997; Yang and Witchard, 1998, Yang and Davis, 1999; Yang 2005). However, methods are required to allow the utilisation of high levels of concentrates in sintering while maintaining productivity and sinter quality (Han and Lu, 2017)."

Jan 1, 2018

By F. O. Milovich, V. A. Ignatkina, L. A. Samatova, E. D. Shepeta

"The aim of the research was to increase technological parameters of the flotation of finely disseminated scheelitecarbonate ore using selective reagent regime.In the studies the monomineral fractions of scheelite and calcite; samples of the scheelite-carbonate ore of the Primorsky deposit with the range of the carbonate module 3-65 were used. A carbonate module of ore is the ratio an initial assay of calcite to an initial assay of scheelite. Sodium oleate, iso-decyl alcohol, water glass, calcium chloride, soda or sodium hydroxide as flotation reagents were used. The flotation method in the Hallimond tube and in a mechanical cell, an adsorption method for study the kinetics of adsorption of oleate and isodecyl alcohol and its combinations on scheelite and calcite, IR spectroscopy including ATR to study the composition of surfacecompounds were applied. Selective reagent regime may include two ways - a combination of collectors or a modification of depressants of calcite and other gangue minerals. On one hand the combination of sodium oleate and higher fatty iso-alcohols of fractions C12-C16 in the rough scheelite flotation to reduce the flotation activity of calcite has been studied. On the other hand depression of calcite flotation by calcium chloride with water glass into rough flotation was used; modified the steaming cycle by Petrov's method applying change the concentration of water glass and other. Fatty iso-alcohols can adsorb on the surface of the calcite that reducing the adsorption of sodium oleate and floatability of calcite has been fallen. Their co-adsorbing with oleat on the scheelite surface were support the hydrophobization and flocculation of slime particles of scheelite. Flocculation of the particles of scheelite leads to increased up 3 times of the recovery of scheelite from the slime class, and calcite change up only 1.4-1.1 times it’s recovery.The growth of the carbonate module more than 11 is decreased the assay of WO3 in the scheelite concentrate of selection cycle."

Jan 1, 2018

By D. Izerdem, S. L. Ergun

"Beneficiation of the finely disseminated valuable minerals has been an important issue in the mineral processing field for decades. Treatment of the fine materials becomes difficult with using traditional gravity concentration equipment. To investigate particles behavior in a commonly used conventional gravity concentration equipment, a comprehensive study was undertaken in a plant, which only consists spiral concentrators as concentration units. Spiral concentrators require relatively coarse material to effectively concentrate valuables as well as offering greater simplicity for especially higher grade feeds. In the current work, chromite ore (d80 = 290 µm) was treated using spiral concentrators and the performance of spiral concentrators was examined. The design of the separation circuit comprised of rougher, cleaner and scavenger stages. The resultant fractions produced by each separation unit and feed samples were analyzed to identify the particle sizes, mineral liberations and chromite content. Grade and recovery comparisons were presented in size-by-size manner and the separation tendency of the particles were determined in varying feed rate conditions. The overall results indicated valuable mineral loss of the plant and alternative suggestions were pointed to reach the target values.INTRODUCTION Spiral concentrators are simple low energy consuming devices, which are generally used for pre-concentration of the minerals. They are cost efficient equipment separating minerals mainly based on density differences of the minerals. The adjustable splitters remove the concentrate as the remaining stream continues to move down the spiral. Separation on a spiral is achieved through a combination of forces that act on particles as they move down the trough of the spiral. The main forces known to act on the particle on a spiral are the gravitational force, centrifugal force, hydrodynamic drag and Bagnold force (Atasoy and Spottiswood, 1995; Burt, 1984). Since the classification in a spiral concentrator depends on particle specific gravity and size, the operation of spirals can be analyzed using size recovery or partition curves (Bazin et al., 2014). Spiral concentrators possess multiple design parameters for a variety of applications. The design parameters that govern the performance of the spiral can be identified as the diameter, number of turns, slope, pitch and the profile of the trough. For an efficient separation on a spiral concentrator, the properties of the slurry flowing on a spiral, ore texture, percent solids and flow rate play important roles."

Jan 1, 2018

By Lutz Rolf, Halit Z. Kuyumcu, Salas Cazón. Milton A.

Aim of experimental investigations was the mathematical description of the abrasion process running with a single particle stress. This is on the one hand the basis for the physical interpretation of the process, on the other hand the base for the simulation of abrasion processes carried out in technical scale. With this investigation for the first time the influence of the particle shape changing with increasing abrasion progress was quantitatively described. This influence affects itself particularly strongly on break-fresh particles up to an abrasion degree of approximately 10 to 20%. This is for the description of technical processes the most interesting area.

Jan 1, 2003

By M. Ito

The authors have developed the RETAC jig (a modified TACUB jig) and have reported that the RETAC jig can separate relatively low density particles such as plastics. To further improve the separation ability, a hybrid jig (a RETAC jig with an air bubbler under the particle bed), which can separate plastics having similar specific gravities by the differences in the wettabilities of the particles was developed. Surface modification of plastics with similar wettability enabling separation in the hybrid jig and the effects of wettability control of the plastics using reagents are reported.

Sep 1, 2012

By W. P. Roux

With depletion of higher grade iron ore reserves, and the need to process finer, lower grade material; there is a need to better understand the recovery efficiency of jigging process. The use of Positron Emission Particle Tracking (PEPT) was examined as a technique, to study the motion of particles inside a laboratory batch jig. PEPT is a noninvasive method that can provide three dimensional kinetic data of a particle during jigging. Particles with different densities and sizes were traced under the same jigging parameters, to obtain a data set that can be used for the development and verification of jigging models. From the results, detailed information on the stratification rate of a particle was obtained, with adequate resolution to see particle movement through an individual pulse. Detailed data of this nature is critical for the validation of CFD and DEM models. Keywords: positron emission particle tracking, jigging, jig models

Sep 1, 2012

By Cagri Emer

In conventional mechanical flotation cells, when the size of particles exceed a particular value, that is of the order of 100 µm for metal sulphides, the recovery of particles decline rapidly. It appears that the turbulence in the agitated vessel is sufficiently intense to rupture the forces of attraction between the particles and the bubbles, so the large particles are flung off the bubbles in the turbulent field. It has recently been suggested, that a fluidized bed would be a very favorable environment in which to contact bubbles and the particles. In a fluidized bed, particles are supported by rising flow of fluid, which separates them from each other and allows them to move freely while remaining close together. In this novel method, bubbles injected into the fluidized bed are able to rise through it, colliding with hydrophobic particles, transporting them to the top of the column where they can form a froth layer that overflows into a launder. The flow in a fluidized bed is generally slow and nonturbulent, and preliminary experiments have shown, that it is possible to collect mineral particles as large as 1 mm and coal particles as large as 5.5 mm. If the upper particle size limit can be extended, there could be significant reductions in the overall energy consumption in concentrators. Calculations show for example that if the top size for flotation could be increased from 100 µm to 400 µm, there would be a reduction in grinding energy of the order of 40%. It is therefore, important to study the mechanism of coarse particle capture in fluidized beds. In this work, the factors governing the capture rate of particles, particularly the particle and bubble size, the fluidization velocity and the superficial gas velocity have been investigated, and the results will be presented.

Sep 1, 2012

By M. Ranjbar, M. Khosravi Rad, A. Tohry

"The filling degree is defined as the volume ratio of the load inside the mill, which determines the power drawn from the motor, as long as the filling degree is not more than the optimum level. As the filling degree increases beyond the optimum level, the impact energy inside the mill will decrease and as a consequent, the mill power output will also decrease. Therefore, the mill filling degree is a key parameter in evaluating the grinding circuit performance, as it determines the mill reaction to the input feed. Since this parameter has an impact on the mill capacity, measuring the mill load is vital for control and optimization of grinding process. As in Choghart Processing Plant no instrument is available to measure the AG mill filling degree, an empirical model based on the bearing-oil pressure is proposed. The AG mill filling degree was related to the differences between the average pressure of input and output bearings, the circulating load and power drawn. It was shown that a quadratic model could relate the mill filling to the above mentioned measurements. This model showed that when the power drawn and circulating load decreases the bearing-oil pressure needs to be checked. If the bearing-oil pressure increases the feed rate needs to be decreased and steel ball be charged to the mill to increase the grinding and prevent mill overloading. INTRODUCTION The feed quality (size and hardness) affects the grinding process in AG mills. Reducing the top feed size and increasing the ore hardness reduce the mill efficiency and increase the particles with critical dimensions inside the mill. These will result in increasing the mill filling degree and reducing the mill throughput and efficiency (Wills and Finch, 2015). The volume ratio of the load inside the mill is called filling degree, which determines the mill power drawn. It is believed that if more energy is mainly spent on grinding (Wills and Finch, 2015). Therefore the mill power draw is used as a mean to control the mill efficiency."

Jan 1, 2018

By E. V. Mezentseva, S. M. Okunev

"In the article there is set forth a development experience of JSC LEBEDINSKY GOK Beneficiation Plant concerning the plan of increase in the production volumes of the iron ore concentrate with Fe content more than 69.5%. There are considered the issues regarding implementation of the updated process scheme of the concentrate beneficiation using fine screening operation, its industrial tests have shown an exploitability of this development direction. There are described the issues relating to the ceramic filters for dehydration of the additionally-beneficiated concentrate, there are given the production and process figures achieved during the exploitation. The methods of the research. In the paper there have been used the following scientific research methods: the methods of system analysis, mathematical statistics, classification, comparison, modelling, observance, experiment. INTRODUCTION JSC LEBEDINSKY GOK is the largest leading enterprise for iron ore beneficiation and the unique RF producer of the merchant hot briquetted sponge iron (HBI) highly demanded by the consumers. Raw materials for hot briquetted iron production are fluxed pellets produced from iron ore concentrate with Fe content more than 69.5% (additionally-beneficiated concentrate). Strategic program of the plant’s development foresees expansion of production of the highly demanded products that imposes a necessity of expending capacity of the enterprise and implementation in production of modern processes and equipment having low resource intensity and ensuring in addition a high efficiency. Construction of the third stage of the HBI Plant became one of directions for the strategic development of JSC LEBEDINSKY GOK implemented in 2017 that caused a demand in the production volumes and filtration of the iron ore concentrate with Fe content more than 69.5%. Purpose of the work – to develop and to provide a rationalization for efficiency of the production process and filtration of the iron ore concentrate with Fe content more than 69.5% ensuring increase of production volumes and its prime cost."

Jan 1, 2018

By T. C. Sun

Two wasted activated sludges (WAS), from an industrial wastewater treatment and a sewage treatment plant respectively, and 7 collectors are used to investigate the feasibility of air flotation thickening of WAS by adding the collectors used in mineral processing. The collectors experimented include straight chain fat acids with different chain length, sodium oleate, alkyl sodium sulphonate, sodium dedecylsulfonate, and dodecylamine. The results show that the thickening efficiency varied depending on different collectors. Of the collectors experimented, dodecanoic acid and dodecylamine are best collector for thickening both sludges.

Jan 1, 2014