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By F. Burat

The present research covers the results of experiments carried out with high frequency vibration screen on dewatering of coal fines. In the tests, the addition of surface active reagents was studied employing a high frequency vibrating screen. To increase the efficiency of mechanical dewatering processes, ultrasonic treatment was applied along with surfactants and optimum dewatering conditions were obtained. The moisture content of the feed material was from 82.5% to 41% by the optimization of operation parameters including the angle of the screen, vibration frequency, feed rate and screen opening size. Optimum parameters obtained in dewatering processes carried out with the vibrating screen were kept constant and the effects of surface active reagents and ultrasonic treatment on dewatering were investigated. Finally, the moisture level of the material was further reduced from 41.0% to 37.66%.

Sep 1, 2012

By I. Gombköto

In the EU-region, the automatically operated approximately 200 (rotating hammer) shredder plants processing large technical equipment (end-of-life vehicles, large household appliances) annually produces 8-9 million tons of non-metallic grinded by-product, which ends in landfills, without recovery. Although this by-product is organic material, still contains large amount of metal components worth recycling. These operations, such as shredding and processing end of life vehicles or mixed metal components are a growing market and it is become more potential if EU directive 2002/96/EC will become obligatory for new member and candidate countries and they have to apply EU regulations. Eddy current separators (ECS) are one of the most important units of separation of non-ferrous metals from insulators in waste recycling. The product of ECS processing of shredded ELV?s is usually a mixture of Al, Cu, Brass and stainless steel. This mixture has relatively low price on the market, while purified metal products are required by smelters for which shredder operators are able to get even higher price. Our aim at University of Miskolc was to find solution producing pure metal products using dry separation processes. Authors are presenting a possible solution, using ECS. Institute of Raw Material Preparation and Environmental Processing possesses an ECS, equipped with 305 mm wide belt, and a concentric magnetic rotor. The subject of our work was to investigate the behaviour of model particles with different shape, conductivity (aluminium and brass), orientation and size in order to separate Al and Brass. We used model particles with similar shapes of shredder plant originated ones. The magnetic flux and magnetic frequency was constant and derived by the design of the rotor. During our research work, belt speed and rotor speed of ECS were varied. The particle distance and trajectory caused by throwing was determined and the results are reported in this paper.

Sep 1, 2012

By Georg Unland, Thomas Wegner

"Different types of impact crushers use the physical effect of impact to crush rocks. The rocks can vary from soft to hard and from ductile to brittle but they should never be abrasive. Since the principles of impact crushing of larger rocks are hardly investigated these crushers are still sized rather by empirical than by scientific approaches.In order to investigate the principles of comminution by impact of large rocks a test rotor was developed and rocks of different dimensions were tested. The integrated measuring devices of the rotor enable the recording of impact forces and of absorbed impact energy with high resolution during the contact time.Since impact crushers stress the rock particles with a defined velocity the main crushing properties are gained as a function of the applied velocity and the particle size of the rock: likelihood of breakage, contact time, maximum crushing force, mass specific crushing work, surface related crushing ratio and crushed fragment shape distribution."

Jan 1, 2003

By P. C. Beuria

Iron ore concentrate contains different mineral phases viz. hematite, magnetite, goethite, kaolinite, and gibbsite. Presence of some of these phases like goethite, kaolinite, and gibbsite contribute to the loss on ignition (LOI) content of the sample. Iron ore fines (pellet feed) are pelletized for utilization in DRI & BF processes. In the present pelletization technology i.e., straight grate and grate kiln processes, the LOI in the ore should be within the range of 2.0-2.5%. LOI content in the iron ore concentrate is found to be more than 4% after beneficiation of low-grade iron ore. It is therefore difficult to produce good quality pellet because of high LOI content. The LOI content of the sample is a detrimental factor in the pellet making. For effective pelletization, the LOI content in iron ore fines needs to be reduced before pelletization. It can be reduced by fluidized bed roasting. The objective of present work is to understand the kinetics of removal of LOI from iron ore fines. The effects of bed depth, temperature, and residence time on reduction of LOI content in iron ore fines were studied using muffle furnace. The process of roasting was carried out at four different temperatures varying from 400 to 950 °C with a variable residence time of 30, 45, 60 & 75 minutes and at bed depths of 16, 32, 48 & 64 mm. In all instance of experiments carried out, one of the parameters was kept constant. It was observed that at 850 °C and 30 minutes of residence time, there was sufficient removal of LOI in static bed condition even at a high bed depth of 64 mm. Keywords: LOI, pellet feed, fluidized bed roasting, goethite

Sep 1, 2012

By Z. F. Hu

Tourmaline has the characteristics of piezoelectricity, thermoelectricity, spontaneous polarization and far-off infrared radiations. Ultra-fine powders of tourmaline have extensive applications in the fields of electron, chemical and environment protection, as well as health protection. The preparation technology of ultra-fine tourmaline powder is discussed. The key equipment of a pilot plant for producing ultra-fine tourmaline powder with jet mill and stirred ball mill is described. Using this pilot plant facility it is possible to produce tourmaline powder with particle size smaller than 100 nm, and a continuous production process can be realized. The final powder product has many superior performance such as high whiteness and large specific surface area, and it?s a negative ions emission can reach the value of 7190 ions per cubic centimeter.

Jan 1, 2014

By Y. Y. Li, Q. Chen, Y. X. Cai, Q. Zhang, S. Mao

"Due to the influence of combustion conditions, the fly ash produced by some power plants has the problem of high-carbon content. The unburned carbon in fly ash can be removed by flotation, and the decarbon tailings should reach the national standard level I fly ash. The fineness of the requirement is one of the important indicators and is also an important factor affecting the tail ash activity. In this paper,adopting two methods investigate the effect of particle size on the flotation index: one is direct flotation of fly ash, and the other way is wet grinding + flotation of fly ash, comparing the two methods and selecting the appropriate process,which provides a way for the effective utilization of fly ash. INTRODUCTION Fly ash is a solid waste discharged from coal-fired power plants. The annual amount of emissions of fly ash are very large in China. The amount of fly ash were discharged from coal-fired power plants are increasing gradually, and the amount of fly ash stored has exceeded 2.5 billion tons, but the comprehensive utilization of fly ash is not high, which brings about a huge environmental problems( Lu et al.,2011). Carbon is a harmful component of fly ash in cement and concrete application (Zhang et al.,2008). Fly ash decarburization is an essential link to improve the utilization efficiency of fly ash and the reduce pollution ( Yang et al.,2012). Carbon is selected from fly ash to make full use of fly ash resources and improve utilization of fly ash (Li et al.,2008). In this paper, the flotation decarburization of high-carbon fly ash is studied, through comparing the grinding and not-grinding processes, optimizing the separation process of fly ash, which provides a way for the effective utilization of fly ash."

Jan 1, 2018

By Francisca San Martín, Martin Rudolph, Willy Kracht, Tomás Vargas

It has been shown that bacteria Acidithiobacillus ferrooxidans can be used to depress pyrite in seawater flotation at natural pH, which opens the possibility for its use as an alternative to lime to depress pyrite in copper sulfide flotation. In order to have a better understanding of the mechanisms involved in pyrite depression with A. ferrooxidans, an exploratory experimental campaign was carried out, including attachment density and contact angle measurements, and the effect of adding bacteria before or after collector. Biodepression of pyrite improves when increasing pH from 3 to 8, with a decrease in recovery from 92% to 36%. This increase in depressing capability is accompanied by an increase in attachment density, from 2.58×108 bacteria/g to 1.99×109 bacteria/g at pH 3 and 8, respectively, suggesting that the mechanism of depression is related to the attachment of bacteria to the pyrite surface. It was observed that the conditioning sequence with collector and bacteria influences the biodepression capacity of A. ferrooxidans. Having as a reference a value of pyrite recovery equal to 97%, when using only xanthate in seawater flotation at pH 8, the effect of both conditioning with bacteria-followed-by-xanthate and xanthate-followed-by-bacteria were assessed. When bacteria were added before the collector, the recovery of pyrite decreased to 36%. On the other hand, when bacteria were added after collector, the recovery was 64%, showing that biodepression of pyrite with Acidithiobacillus ferrooxidans is more efficient when the conditioning is carried out first with bacteria. The contact angle values show that there is little effect of the second component added to the system, i.e., if pyrite is first conditioned with bacteria, the contact angle does not change significantly once the xanthate is added (bacteria-followed-by-xanthate). The same was observed when the conditioning sequence was xanthate-followed-by-bacteria.

Jan 1, 2018

By L. O. Filipov, N. E. Menad, A. Geneyton

"Zeta potential of synthetic monazites presenting various compositions were measured to investigate the effect of the main lanthanides substitutions on electrophoretic mobility and resulting IEP. The measurements are performed in a CO2 depleted and enriched solutions showing both reduced influence of monazite chemistry and strong influence of ions resulting from the solubilization and dissociation of CO2. The influence of oleic acid on the electrophoretic mobility of those monazites was also investigated. The influence of pH on oleate adsorption was studied using a bubble/particle adhesion system. Adhesion strength measurements were performed on pure synthetic monazite-(Ce) and monazite-(La). An extensive thermodynamic model of monazite in water was developed to highlight correlations between lanthanides hydroxides/carbonates species concentrations in the bulk solution and oleate adsorption. Based on electrophoretic measurements, advanced thermodynamic consideration and adhesion measurements, further details of the oleate adsorption model on monazite surface were proposed.INTRODUCTION Electrophoretic and potentiometric data on monazite and, a fortiori, other rare earth semi-soluble salts such as bastnaesite are extremely erratic (Chelgani et al. 2015). The isoelectric points measured with electrophoretic mobility methods range from 4.7 to 6.5 although sporadic data indicates an IEP (isoelectric point) far from that range. Different explanations are proposed in the literature to explain the IEP variability notably the numerous chemical substitutions that frequently occurred within monazite crystal lattice (Chelgani et al. 2015). Based on lanthanides speciation diagram, several authors highlighted the influence of specific lanthanide species on the flotation performance of rare earth semi-soluble salts when carboxylate or hydroxamate collectors are used. Although lanthanides ions have a great affinity for carbonates groups (Kragten et Decnop-Weever 1987), lanthanide (hydrogen) carbonates were not implemented in speciation diagrams. In this work, an advanced thermodynamic model is proposed to highlight correlation between flotation performance and lanthanide species predominance but also concentrations. Qualitative measurement of the monazite surface hydrophobicity are performed through tests of adhesion of coarse monazite particles onto bubbles. Since flotation and microflotation technics are highly influenced by hydrodynamic parameters, this method was investigated to obtain a sharp contrast between appropriate and inappropriate pH conditions. This paper is to investigate 1) the effect of lanthanides substitution on monazite surface properties through zeta potential measurements, 2) the mechanism of adsorption of carboxylates on monazite surfaces and 3) the effect of CO2 on monazite surface properties and carboxylates adsorption."

Jan 1, 2018

By S. K. Chaurasiya

o meet the ever increasing demand of iron oxide feed stock for rapidly growing domestic steel industries and to effectively manage the depleting reserve of high grade lumpy iron ore, Pelletization of iron ore fines/slimes are expected to play a dominant role in the near future. Use of pellets will also enable the blast furnace operator to achieve higher levels of productivity with lowering of operating cost. The effective utilization of Iron Ore Slimes is important not only from the point of view of optimum utilization of Iron values in the mined ore but also for preventing environmental pollution. A significant amount of slime is being accumulated at the tailing dam of one of the iron ore mines and with the present scale of operation the tailing dam will be filled in another 10 years. Hence to increase the life of tailing dam and for better utilization of the iron values a study has been carried out for the suitability of pellet manufacturing with slimes and fines at our laboratory. The pelletization studies are aimed for optimization of various parameters for production of Blast furnace/ DR grade pellets from beneficiated slimes and Fines. This paper attempts to describe the production of blast furnace grade pellets from beneficiated slime and fines and its characterizations.

Sep 1, 2012

By F. C. Araújo, T. Tavares, J. Leite

"This work presents the small-scale mining cluster of kaolin in Rio Grande do Norte (RN) and Paraiba (PB), both Brazilian states, including the following information: number of companies, process flowcharts, production numbers, mineralogical (XRD) and chemical (XRF) composition, granulometric distribution (screen and laser granulometer) and image analysis (SEM). Some social indicators in the region of the RN and PB States are presented in association with these data. The number of companies and their flowsheet were obtained through in situ visits and sample collection for technological characterization. The comparative study of the different flowsheets for kaolin production in the world was done using the databases and presenting the state of the art of kaolin processing. The results indicated that the mean feed typically contains 35-39% kaolin with quartz, muscovite and kaolinite as main mineralogical components and SiO2 (65.83%), Al2O3 (21.19%), K2O (3.9%), and Fe2O3 (0,63%) as main chemical constituents. The products of mineral processing are twofold, one between 74 µm and 37 µm, and the other smaller than 37 µm. The wastes of operation had major quantities of kaolin. The average Human Development Index (HDI) of the cluster region is approximately of 0.61, which shows an association between mineral processing plant and social indicators. The kaolin recovery, however, is between 30-55% for the three most common types of flowsheets that are currently used in the small kaolin mining cluster, indicating a need for technological improvement to achieve regional development. These data could be used incrementally to adapt the process plant currently used in the small-scale mining cluster of kaolin."

Jan 1, 2014

The simulation study on the process of iron ore beneficiation plant of Essar Steel, Kirandul was carried out. The iron ore fines and slimes generated nearby Bailadila mines of NMDC are used as raw materials for this beneficiation plant. The capacity of the plant is 1400 TPH operating in parallel in two streams. The capacity of the plant was utilized about 60% of throughput capacity. To improve the plant capacity as well as quality performance, the simulation study was conducted to detect the bottleneck of the process. The process samples were collected from input and output of each processing unit operation to generate the data base for simulation study at the feed rate of 400 and 500 TPH of iron ore fines in a single stream. The characteristics data i.e., breakage and selection functions were generated using MILLSOFT package for simulation of ball mills. Then MODSIM package was used to evaluate the performance of each unit operation to identify the bottleneck. It was established by a simulation study that the intermediate thickener draws high current when the feed rate is more than 400 TPH due to high torque drawn by rotating rake because of presence of coarse particles in the input stream to thickener. The problem was sorted out by classification of input stream of thickener to remove the coarse particles. Then the process was simulated at its rated capacity, and experimental validation studies at the plant were also conducted at the feed capacity of 600 and 700 TPH by modification of process flowsheet. The experimental data was almost matching with simulated data. Finally, the processing plant is running with full rated capacity without any bottleneck. Keywords: simulation of ball mill, breakage function, selection function, iron ore

Sep 1, 2012

By Shuji Owada, Shinya Suzuki, Chiharu Tokoro, Daisuke Haraguchi, Sayaka Izawa

"Coprecipitation with ferrihydrite has been one of the major treatment method for As(V) removal from wastewater such as acid mine drainage. We already confirmed coprecipitation of As(V) with ferrihydrite consists of two kinds of mechanism; one is two dimensional As(V) uptake to the surface of ferrihydrite by surface complexation and another is three dimensional As(V) uptake into ferrihydrite by surface precipitation. We also already confirmed As(V) adsorption process by ferrihydrite could be quantitatively evaluated by original surface complexation model with parameter values reported by Dzombak and Morel. However, As(V) coprecipitation process couldn’t quantitatively be represented by only the original model. In this study, construction and calculation using surface precipitation model were attempted for As(V) coprecipitation treatment with ferrihydrite. In the surface precipitation model, precipitation was described by the formation of solid compound between ferrihydrite and ferric arsenate. Activity of these precipitates was determined by surface precipitation ratio of FeAsO4(s) obtained experimentally from XANES analyses. Solubility products of surface precipitation of FeAsO4(s) (Ksp_FeAsO4(suf.)) were determined by fitting to sorption densities and surface precipitation ratio in each condition. The values of Ksp_FeAsO4(suf.) were determined 10-7.7 at pH5 and 10-10.2 at pH7, respectively. Based on the obtained Ksp_FeAsO4(suf.) value, As(V) removal and isotherm were calculated for As(V) co-precipitation treatment using surface precipitation model. Good agreement between experimental and calculated values was observed. These results were suggested that the quantitative prediction of As(V) co-precipitation treatment was possible if Ksp_FeAsO4(suf.) value was estimated experimentally."

Jan 1, 2014

By William Skinner, Jennifer MacCarthy, Jonas Addai-Mensah, Ataollah Nosrati

"Acid leaching in agitated tanks is central to hydrometallurgical processing for valuable metals’ (e.g., copper, gold, nickel and cobalt) recovery from low grade (e.g., < 2 wt.%) ores. In this study, atmospheric leaching behaviour of Australian saprolitic nickel (Ni) laterite ore using sulfuric acid was investigated under isothermal, batch conditions at pH 1. The effect of primary process variables comprising time (4 h) and temperature (70 and 95 oC) on the leaching mechanisms and kinetics was established for -2 mm, low grade (~1 % Ni) saprolitic ore dispersions at 40 wt.% solid loading. Leaching proceeded incongruently, reflecting the proliferation of gangue minerals’ constituent elements (e.g., Mg, Al, Fe) alongside Ni and Co in the pregnant leach solutions (PLS). Subsequent analysis showed that 89% Ni and 78% Co were extracted after 4 h at 95 oC whilst at 70 oC the recoveries of these metals were markedly low (< 25 %). Overall, 177 and 644 kg H2SO4 /t dry ore were consumed at 70 and 95 oC, respectively. Activation energy of 79.0 ±1.0 kJ/mol was estimated for the mechanism of Ni and Co leaching and associated kinetics. Particles size analyses indicated that when the breakage of frail laterite particles due to shear is taken into consideration, differences in feed and leached product particle size distributions were insignificant , despite a remarkable increase in BET specific surface area of the product. Mineralogical analyses of the feed ore and leached solid products revealed a sub-crystalline silica phase enrichment of the latter. The overall results suggest that the mechanism of acid leaching of saprolitic Ni laterite may be described by a chemical reaction-controlled, shrinking core model."

Jan 1, 2014

By Mario Gerards, Sergej Podkow, Marco Steinberg

"The JONES® WHIMS technology is based on the magnetic separation process and is widely used for the recovery of magnetically susceptible iron ore particles. The conventional machine design is well-known within the iron ore beneficiation industry for more than 50 years and recognized to be highly reliable, robust and extremely compact with the advantages of high capacity and selectivity. In 1981 Rana Gruber AS, Norway bought 14 JONES® WHIMS DP 317 separators when the magnetic separation plant was built and erected. Today, 11 of these old machines are still operating profitably and efficiently. The former supplier was the coal and minerals division of Klöckner-Humboldt-Deutz (KHD) which is today MBE Coal & Minerals Technology GmbH (MBE). This paper outlines a detailed description of the project of revamping the above mentioned old machines and describes the challenge of incorporating enhanced and newly developed technology into an existing processing plant. Further it gives an overview of the recent developments on the design of the JONES® WHIMS. In order to meet modern product requirements and to increase and secure plant productivity, in 2012 Rana Gruber AS settled a contract covering two new designed JONES® WHIMS DP 317 HFR separators to be implemented into the existing building and the upgrading of all 11 older JONES® WHIMS under the use of as many refurbished items as possible. The two new machines were fully developed by the product specialists of the supplier in cooperation with the operator Rana Gruber AS, thereby taking advantage of their great experience. The design of the new machine is based on the conventional design, i.e. the general operating mode as well as the overall dimensions are identical. Finally this paper gives an overview about the erection and commission phase of the two new machines and gives a detailed comparison between conventional and enhanced WHIMS technology."

Jan 1, 2014

By V. M. Mankov, O. V. Zamyatin

"Fine free gold at a size of minus 250-100 µm can be effectively recovered from mineral materials (buried clay placers, saprolites, gold-bearing aggregates, technogenic sands etc.), or MM, using some developed and implemented in practice cost-effective basic technological schemes of MM processing at every stage: exploration, main concentration processes, upgrading of gravity concentrates etc. Such technologies are based on mineral materials composition, different content of fine gold mass fractions, and include improved two-stage sluicing technology, jigging technology, advanced technology and integrated technology. The main operation principle of the given technologies is gravity concentration. They provide recovery of fine gold of any size from MM, including gold finer than 100 µm, using concentration systems and plants with a capacity of 1-2 and up to 100-200 m3 per hour. Selection of a cost-effective technology depends on its technical and economic viability regarding to mineral material composition, optimum performance and concentration rate. The developed technologies of mineral materials concentration establish a balance between technological, technical and economic factors, and ensure profitable development of deposits containing free gold and characterized by a complex composition of concentrating material. Free gold recovery with these systems increases by 2.0-2.5 times for gold particles at a size of minus 250+100 µm and 10-30 times for gold particles of minus 100 µm, compared to conventional sluicing systems. The Irgiredmet Institute has developed and supplies primary concentrate washing machines for upgrading gravity concentrates of up to 100 mm in size, with a capacity of 1.0-5.0 m3/h, fitted with various production equipment including pyro- and hydrometallurgical systems. Additionally, the Irgiredmet Institute develops and manufactures systems of mechanized processing of geological and technological samples (UOMP; registered design certificate No.27505, Russia) designed for complete recovery of free gold in the process of geological samples handling and decreasing of a human factor influence. A system includes a package of technologically associated disintegration, classification and concentration equipment with some “know-how” elements that provide effective recovery of fine gold at the exploration stage. A number of Irgiredmet’s patented technologies and systems (patents of the Russian Federation) have no equivalents in the field of mineral processing and provide designing of technologically practical and cost-effective flowsheets that offer higher recovery of gold of different sizes (fine gold), at every stage of processing of mineral materials including basic concentration processes, upgrading and exploration etc."

Jan 1, 2018

By Azin Zangooi, Cesar Gomez, James Finch

Frother concentration is a variable which significantly affects the flotation performance by decreasing bubble size and helping froth stabilization. Variations in frother concentration, which mostly go unnoticed in industrial operations, may affect these functions. Some factors that can cause variations include the fact that frothers are normally dosed based on feed tonnage and not solution concentration, unstable frother delivery, incomplete dissolution for low solubility frothers, addition of frother-free wash water, remnant frother in recycle waters and frother partitioning to the froth. A colorimetric technique developed for determining frother concentration on site makes it possible to detect the occurrence of these problems and to establish their magnitude, allowing conditions to be adjusted to reduce frother concentration variations. By sampling and analysis, frother distribution throughout a circuit can be established, referred to as ‘frother distribution mapping’. Experiences at several concentrators processing sulphide ores are used to illustrate time restrictions for sample analysis, and to demonstrate temporal and spatial frother concentration changes as a consequence of variations in the grinding stage, recycled waters containing frother, and frother partitioning.

Jan 1, 2014

By D. Krawczykowski, D. Saramak, T. Gawenda

"Annual world zinc consumption is as high as nearly 14 millions of tonnes. Approximately 50% share of zinc is used for corrosion protection in processes of continuous galvanization and the hot dip processes. In the latter, two zinc containing residues are produced: zinc ash and hard zinc, which constitute around 10% each. Paper concerns the method of possible separation of metallic zinc from the non-metallic zinc compounds from the zinc ashes – the waste product of hot dip galvanization process. The investigative programme covered the comminution tests of the feed (zinc ash) in selected crushers: jaw crusher, roller crusher and impactor. Results of investigations show that application of individual crushing device results in various breakage of the feed sample. Impact force caused the highest increase in finest particles size fractions of the product, while metallic and non-metallic fractions were comminuted differently. The compression force, in turn, caused the selective comminution, i.e. the breakage of metallic zinc was observed in a higher degree. The presented approach appears to be an economical supplementary method of initial recovery of metallic zinc from metallurgical zinc waste. For the high demands for the zinc in the world and the need of corrosion protection, the method presented in the paper helps in more effective zinc recovery and environmental protection.INTRODUCTION AND METHODOLOGY World production of metallic zinc during last decade shows a slight increase and in recent years its consumptions reach 14 millions of tonnes. Figure 1 shows world production of zinc in the time period 2009 – 2016. Main directions of zinc utilization include: - Galvanization - Production of zinc alloys - Brass and bronze production - Semi-manufactures of zinc - Chemicals The major share in global zinc consumption constitute galvanization process (Bright 2007). Two main types of zinc galvanization are: hot-dip galvanizing (HDG) and electro-galvanizing."

Jan 1, 2018

By Daniel Saramak

"Issues concerning effectiveness of the high-pressure comminution process in technological circuits of copper ore treatment were presented in the paper. Crushing processes taking place in high-pressure grinding rolls devices (HPGR) are currently one of the most efficient methods of hard ore size reduction in terms of the energy consumption. The HPGR products are characterized by a fine particle size and the micro-cracks formation in individual particles, which appear in downstream grinding processes, decreasing their energy consumption. The purpose of this paper was to analyse the effectiveness of a ball mill grinding process depending on the changeable conditions of run for the HPGR crushing process. The research programme carried out included crushing tests in the laboratory scale HPGR device at various settings of the operating pressure volume and selected qualitative properties of the feed material (i.e. particle size distribution). Particle size distribution analyses of all HPGR products were performed and in the next stage the material was a feed to the ball mill grinding process. Grinding process kinetics were investigated through the determination of mass recoveries of individual particle size fractions after defined grinding time intervals. The models, defining the grinding process effectiveness as a function of changeable conditions of HPGR process run, were determined on the basis of obtained results. Based on these models the optimal grinding time in a ball mill was specified which is, in turn, the basis for optimization of operation of the technological comminution circuits for a given material type. The obtained results proved that the application of HPGR devices in a given copper ore comminution circuit may improve the effectiveness of the downstream grinding process which leads to improvement of the entire circuit work efficiency through decreasing the process energy consumption and enhancing product size reduction."

Jan 1, 2014

By Fuqiang Zheng, Shuai Wang, Feng Chen, Yufeng Guo, Guanzhou Qiu, Tao Jiang

"The direct reduced iron powder and Ti-V-rich material was prepared from vanadium titanomagnetite concentrate by solid-state reduction-magnetic separation. The result indicated that under the studied conditions, adding KS can effectively improve the metallization rate of pellets. 2% KS was well mixed with vanadium titanomagnetite concentrate to make the pellets. The green pellet was preheated at 900 ? for 6 min. The preheated pellet was reduced at 1050 ? for 100 min, then crushed and ground to more than 80% was below 0.045 mm. The direct reduced iron powder and Ti-V-rich material were separated from the slurry by wet magnetic separation at 800Gs. The TFe content of magnetic material was 90.63%, and the Fe recovery rate reached 96.53%. The TiO2 and V2O5 contents of Ti-V-rich material were 28.40 % and 1.64 %, respectively. The TiO2 and V2O5 recovery rates were 69.05% and 96.82%, respectively. 1. Introduction The ilmenite and rutile are the main titanium resources which can be used in the present technical level and economic conditions[1,2]. However, with the rapid development of China’s economy, the market demand of titanium products is increasing sharply. The current supply of ilmenite and rutile cannot meet the needs of chemical industry[3]. China is rich in vanadium titanomagnetite concentrate which contains abundant titanium and vanadium resources. The TiO2 and V2O5 content of vanadium titanomagnetite concentrate are usually about 7% and 0.3%, respectively[4]. Because the TiO2 and V2O5 grades are low, it generally requires pre-concentrated to Ti-V-rich material before extracting the titanium and vanadium. Therefore, it is vital to find effective processes for pre-concentrating the titanium and vanadium in vanadium titanomagnetite concentrate. There are many methods[5-13] developed or under development to pre-concentrate Ti-V-rich material from vanadium titanomagnetite concentrate, including the blast furnace process, pre-reduction electric furnace process, to utilized vanadium titanomagnetite concentrate are direct reduction-electric furnace smelting, sodium salt roasting-direct reduction-electric furnace smelting and direct reduction-magnetic separation and so on. The blast furnace process and other methods cannot effectively utilize the titanium and vanadium resource due to the technical or environmental problems[9]. In this study, the vanadium titanomagnetite concentrate was obtained from Panxi region of China, the reserves of which account for 11.6% of vanadium and 35.17% of titanium all over the world[3]. The preparation of direct reduced iron powder and Ti-V-rich material based on reduction-magnetic separation is proposed. The process utilizes a new catalyst for titanium ore reduction in rotary kiln followed by magnetic separation. Using this novel technology, the titanium-vanadium and iron are successfully separated. Compared to the traditional reduction of Ti-bearing ore, the reduction temperature reduced to 1050 ?, leading to higher efficiency, lower energy consumption and investment, and broader applications."

Jan 1, 2018

By I. Grigoryeva, G. Voiloshnikov, V. Dementyev, N. Moskaeva, N. Voiloshnikova

"Adsorption processes with use of anion exchange resins are widely applied in the gold mining industry of Russia and the former Soviet Union. Anion exchange resin AM-2B and its analogs (with mixed basicity) are used as adsorbents. This paper focuses on the study of weak base anion exchange resin and its comparison with AM-2B resin. Different nature of the ion exchange groups of the adsorbents mentioned above provides essential differences in their properties both during adsorption and elution of gold and silver. Multistage gold elution and resin regeneration procedure is used for AM-2B resin whereas alkaline cyanide solution is used for weak base resin and allows for the reduction Capex and Opex in comparison with AM-2B resin. Anion exchange resins AM-2B and PuroGold S-992 were tested. Weak base resin is sensitive to pH of adsorption medium. Optimal pH value is 10.1-10.3 (at ?? >10.5 gold loading onto resin decreases dramatically). Adsorption isotherms for gold, silver, nonferrous metals, cyanide and thiocyanate ions from synthetic individual metal cyanide solutions were defined. Adsorption of all components onto PuroGold resin was lower than for ??-2? resin. Adsorption of metals from the solution with equal molar metal concentration (0.1 mg-equivalent/L of each metal) was also studied. The affinity of resins to cyanide metals complexes was established. Weak base resin has higher selectivity to gold in comparison with ??-2B resin and is less sensitive to ion composition of cyanide solution or pulp treated. Weak base resin was tested for gold recovery from gold ores. On the base of test results it was recommended to introduce this resin at some new plants in Russia. Commissioning and operation performance of gold plants confirmed efficiency of weak base resin use."

Jan 1, 2014