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By Leonardo Soto, Fernando Villanueva

"Antofagasta Minerals S.A. (AMSA), for its Centinela District Project, is currently developing, at a first stage, a new 90 ktpd Concentrator Plant incorporating Esperanza Sur (ESP Sur) and Encuentro (ENC) ores. In order to dimension properly main equipment, specifically for grinding circuit, a final decision has been taken using geological and metallurgical (comminution) data from both body ores. Data was analyzed internally within AMSA and its consultants to get a final proposed circuit for further engineering studies. Specific Energy Consumption (SEC) parameter is one of the main key factors for proper dimensioning. To get an accurate value different tests have been made and modelled to ESP Sur and ENC ores. Also, operational data from Esperanza operation has been taken into account due to its similar ore characteristics to ESP Sur ore and incorporated as input data for design. Depending on data, quality and amount, it is possible to estimate accuracy for project investment and risk level, hence investment decision can be taken under good and reliable information."

Jan 1, 2014

By T. N. Alexandrova

Results of mineralogical-technological research of carbonaceous rocks of Kimkansky precious metal occurrence are presented, on their basis new typemorphic natural and technological microelement associations were revealed using mathematical statistics methods. Keywords: carbonaceous rocks, processing, microelements, flotation, statistical criteria

Sep 1, 2012

By Ivan Bonchev, Elisaveta Djurova, Evgeni Visariev, Viktor Stoilov

"Two types of slag cooling is used world wide - cooling in ladles and cooling in pits. The flotation comparison of the type cooling regimes was done at Aurubis Bulgaria. In Copper smelter Aurubis Bulgaria (Pirdop), the residual copper in the slags from Flash furnace and Converters is recovered by flotation. The slag flotation plant processes blend of three parts FSF and one part converter slag. The slag processing comprises: pit cooling, crushing, two stages grinding (autogenous and ball) and flotation. The copper content in flotation concentrate is over 20 % and in flotation tail is under 0.5 %. In order to improve the copper recovery, different cooling rate of the liquid slags should be achieved. Three cooling experiments with flash smelting furnace (FSF) slag have been done: two of them in pits with different volume and one cooling experiment in metallic ladle. The ambient air temperature during the cooling tests was from -4 to +4 OC. Laboratory flotation tests in open cycle were done with an aim to compare the slags behaviors cooled at different conditions. In this paper the effect of different cooling on the flotation process will be presented. The copper recovery and distribution by sizes in the tails, copper content in the rougher concentrate, and the concentrate yield are discussed."

Jan 1, 2014

By B. K. Mohapatra

Small manganese ore bodies in south Odisha, India occurs both as stratiform and stratabound ore bodies. These two ore bodies show contrasting mineralogical, petrographical and chemical characteristics. Stratiform type of Mn-ores consists of manganese, iron and silicate- phases in approximately same proportion. In contrast, stratabound ore bodies contain a high proportion of manganese oxides, silicates and phosphorus phases. Phosphorus is found within apatite in the stratabound ore bodies while in the stratiform ore it occurs as an adsorbed state with iron phase (goethite). Both ore bodies are low-grade (17-23% Mn) therefore do not have a market value. However, the stratabound ores are enriched in phosphorus (P2O5: >1%) compared to the stratiform ores. Both the ore types were processed through gravity, magnetic and roast reduction followed by magnetic separation techniques. The strata bound ore could be upgraded to 33% Mn from a feed of 23% by combination of dry and wet magnetic separation methods. But the phosphorus content also suits up (P2O5: 1.2%) in the processed product making it unsuitable for further use. The stratiform ores do not respond to either gravity or magnetic separation because of close association of manganese with iron phases. However, this could be beneficiated through roast reduction followed by magnetic separation. An ore with 17% Mn content could be upgraded to 40% Mn with a 42% yield and 78% recovery. The goethite, having phosphorus, converts to magnetite and is retained within the magnetic fraction, thereby reducing the concentration of phosphorus in the non-magnetic fraction, which becomes the product. This report demonstrates the influence of ore petrology in determining the up-gradational potential of manganese ore in the southern Odisha, India. Keywords: manganese ore, physical beneficiation, phosphorus rich ore

Sep 1, 2012

By Z. G. Song, C. Y. Sun, X. R. Zhang, Y. Yu

In skarn type scheelite deposit, there are calcium minerals with floatability similar to scheelite, such as calcite, fluorite, etc., which are difficult to separate. Heating cleaning method developed by Petrov has been widely applied in processing rough concentrate of scheelite for nearly half a century, but there exists a general lack of full understanding of the interaction between floatation reagent and mineral particles surfaces. The mechanism on separation of scheelite and calcium minerals in heating cleaning process was investigated by mineral flotation experiments, XPS analysis, as well as solution chemistry and crystal chemistry calculations. The results showed that the sequence of minerals floatability using sodium oleate as collector and a large amount of sodium silicate as modifier in heating flotation test was scheelite > calcite > fluorite, which was the same as solution chemistry calculations based on Gibbs free energy vs. pH and also the same as Ca-X intensity order by crystal chemistry analysis. There are two sides about the mechanism of heating cleaning method: one is that the adsorbed collector on calcium minerals surface is desorbed more easily than scheelite, and the other is selective dissolution of calcium ions from the mineral surface because of Ca-X intensity difference in heating and stirring process.

Jan 1, 2014

By P. Oliveira, A. Peres, A. Silva

"The decrease in iron content and increase in contaminants grade, associated with greater participation of compact and semi-compact materials, has impacted the recovery of a mechanical cells flotation circuit in the Iron Quadrangle, Brazil. The recovery decrease in the flotation stage motivated the current conventional flotation circuit reevaluation seeking alternatives to restore the recovery, without affecting the final concentrate quality parameters, with low investment. Sampling, chemical characterization of samples, bench scale flotation experiments, and mass balances were conducted. Analysis of the results showed opportunities to improve the circuit performance. The stages prior to the flotation circuit changes were: rougher, cleaner, recleaner and scavenger. In the previous configuration, recleaner was operated as cleaner scavenger and the iron grade in the scavenger concentrate was 23%, representing 38% of the new feed. After the circuit change, the circulating load was reduced from 38% to 15% and the iron content was upgraded to 42%, resulting in increased residence time. The iron content in the global tailings of the concentrator was decreased from 10.9% (year of 2013 average) to 10.2%, representing gains in both mass and metallurgical recoveries.INTRODUCTIONRegarding plant practice, the year 1972 represents a landmark for the concentration of iron ores in Brazil. VALE started up 28 units of WHIMS (wet high intensity magnetic separators) at the Cauê plant in Itabira, each one producing 1x106 t/year of concentrate. Later 17 WHIMS machines were commissioned at Conceição. During the 80’s decade of last century, changes in the ROM required the addition of a cleaner flotation stage to decrease the silica content in the pellet feed.The first company to use reverse cationic flotation as the only concentration operation of iron ore was SAMARCO (start up in 1977). Since 2015 flotation has been utilized at VALE in Itabira as major concentration process, magnetic separation acting as scavenger stage.The Jones matrix type WHIMS were manufactured for decades under patent by KHD Humboldt Wedag. After the expiration of the Jones patent, Eriez Magnetics took the world leadership regarding WHIMS manufacturing. The Brazilian branch of Eriez is Inbras. Based on plant practice experience at the Fabrica concentrator, the Brazilian company Gaustec was established (RIBEIRO and RIBEIRO, 2010) and is now present in different countries. The mega sized WHIMS GHX-1400 (18.000 Gauss, gaps smaller than 1.5 mm) were developed to face the challenge of huge throughput required by iron ore processing (Ribeiro et al, 2017)."

Jan 1, 2018

By E. Kusaka, M. EL Salmawy

"The electrokinetic behavior of EL Maghara coal has been investigated in the presence of nonyl and octyl nonionic surfactants containing polyethoxy of different sizes with trade names of Triton-X100 (TX-100), Triton-X 705 (TX-705), Triton WR-1339 (TWR-1339) and Brij 58. The electrokinetic behavior was determined by zeta potential measurements. Zeta potential measurements were conducted by Laser-Doppler electrophoresis technique using zetamaster. The results show that the zeta potential of Egyptian coal varies with pH value, the hydrocarbon chain and number of ethoxy groups in the hydrophilic group of the surfactant. It was found that the polymeric surfactants reduce the negative values of zeta potential of coal. The shift of PZC of coal upon deashing appears to be closely relevant to silicate mineral removal."

Jan 1, 2014

By Liu Xiaodong, Jiang Meifen, Kou Xiaoyan, Lu Xianjun

"Two low grade calcium bentonite (Ca-bentonite) from Hejia (HJ) and Boteng (BT), Shandong, China, mainly contain montmorillonite and quartz, and slightly feldspar, calcite, and montmorillonite content are 32.37% and 55.90%, respectively. In order to examine the feasibility to produce activated clay to meet the standard of Chinese chemical industry (HG/T2569-2007), three types of industrial production process are proposed according to the screen test. The first process is grinding the raw bentonite to -200 mesh and then activating. The second is to activate the raw bentonite directly, and then classify the production to -200 mesh. The last one is to activate the raw bentonite after purification. Three parameters, which are sulphuric acid strength, ratio of liquid to solid and treatment time, are optimized via orthogonal test for every process. The preliminary test indicates that it is feasible to produce acid bentonite of difference quality. For the sample of HJ, milling the raw to -200 mesh first and activating afterwards, the parameter is at 9% acid strength, the ratio of liquid to solid 2, the time 4 hours, temperature 90°C, the products can meet the qualified grade for animal and vegetable oils refining. For the sample of BT, milling the raw to -200 mesh first and activating afterwards, the parameter is at 15% acid strength, the ratio of liquid to solid 2.5, the time 2 hours, temperature 90°C, the products can meet the qualified grade of high decolorization for petroleum products refining. For the sample of BT, adopting purification to -325 mesh by stirring and rubbing at first, and then activating at 9% acidity, under the conditions that the ratio of liquid to solid is 2, the time is 2 hours and the temperature is 90°C, the products can meet the first grade of high activation degree for petroleum products refining."

Jan 1, 2014

By S. M. Narbekova, L. V. Semushkina, Zh. A. Aldybayeva, A. A. Mukhanova, D. K. Turysbekov, N. K. Tussupbayev

More complex and heavy-concentrating oxidized and mixed sulphidic oxidized ores are involved in production because of increasing needs for non-ferrous metals. Extraction of the oxidized minerals of non-ferrous metals general in current technologies. The problem is solved to oxidized polymetallic ores the preliminary selective sulphidization is the oxidized surface of the components by means of hydrogen sulphide, sulphide and calcium polysulphide, and also element sulphur, etc. The task was to study details of flotation of the oxidized lead-bearing ore of the Zarechnoe deposit (Kazakhstan) with calcium polysulphide as sulphidation. According to chemical analysis initial samples of the ore contain, %: lead – 4.8; zinc – 0.1; general iron – 0.81. Phase structure lead is characterized by the oxidized form of 57.76-64.5 %; by sulphidic status of 25.5-32.64 %, and by plyumboyarosite of 19.0-23.02 %. Researches on flotation beneficiation of oxidized lead-bearing ore are conducted. Sulfidizator gave to grinding, on flotations there were used the collector (butyl xanthogenate of sodium) and frother (T-80). Experiments were conducted with a new sulphidizator – calcium polysulphide. The latter is obtained by interaction of CaO calcium oxide with sulfur and water at high temperature with component mass the following ratio S:CaO:H2O =10:5:85. Extent of mill initial ore was optimised (88.42 % of - 0.071 mm grade). For the optimum mill mode the studies on matching of an optimized consumption of sulphidizators are performed. On basic technology with application of sulphide of sodium as a sulphidizator at optimum mill, the lead concentrate with the content of lead 64.4 % at extraction of 86.6 % was received. The content of cerussite in a concentrate was about 14.9 % at extraction of 82.1 %. With application of calcium polysulphide as a sulphidizator the lead concentrate with the content of lead 68.0 % at extraction of 88.0 % was received. The content of cerussite has made 16.0 % at extraction of 85.0 %. Application of a new sulphidizator allows to increase extraction of lead in a concentrate from 64.4% to 68% and cerussite extraction – from 82.1 % to 85.0 %. The possibility of application of calcium polysulphide as a sulphidizator instead of conventional sulphurous sodium was established.

Jan 1, 2018

By A. Javadi

"Our recent studies revealed that the sulfide minerals in contact with water during grinding produced hydrogen peroxide (H2O2) where the amount of H2O2 production by the minerals found to be in the order of pyrite > chalcopyrite > sphalerite > galena. The H2O2 effect on the oxidation of pulp components and its influence on the concentrate grade and recovery in flotation have been studied and the results have been presented and discussed in this paper. Studies have also been carried out to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp and as well of controlling the formation of these species through known chemical means for depressing the generation of the oxidant. Flotation tests using a complex sulfide ore with the same reagent scheme that is being used at Bama concentrator in Iran but with the addition i) Na2S reductant and ii) inorganic (EDTA) and organic (TETA) surface modifiers, during grinding stage have been performed to judge the beneficial or detrimental role of H2O2 on the selective flotation of sulfides. The results demonstrate that the selectivity of metal sulfides against pyrite increases with increasing generation of H2O2 in the pulp liquid.INTRODUCTIONOur recent studies have illustrated the formation of hydrogen peroxide (H2O2) by metal-sulphides during grinding in the presence and absence of oxygen (Javadi Nooshabadi & Hanumantha Rao, 2013a; Javadi Nooshabadi & Hanumantha Rao, 2013b; Javadi Nooshabadi & Hanumantha Rao, 2013c; Javadi Nooshabadi & Hanumantha Rao, 2014). In the absence of oxygen, it was found that pyrite surface is catalytically active and able to breakdown water molecules to form OH• free radical and thereby deriving oxygen in the formation of H2O2 from water molecules. The in-situ formation of H2O2 and its influence on sulphide flotation has not been addressed yet. The presence of strong H2O2 oxidant in the pulp liquid and its selective oxidation of pyrite would be beneficial in depressing pyrite flotation. Therefore, it is important to build correlation between percentage of pyrite in the concentrate, grinding conditions and concentration of OH•/H2O2 in the pulp as well as to study possible ways of flexibly controlling the formation of these species through known chemical means for depressing the generation of the oxidant."

Jan 1, 2018

By Jonas Addai-Mensah

Despite the fact that nickel (Ni) laterites accounts for about 60 % of the world?s nickel mineralization, commercial processing of complex, low grade Ni laterite ores by conventional beneficiation (e.g. magnetic, electrostatic and flotation separation) still presents intractable challenges, particularly in heap leaching. Invariably, low grade laterite ores require aggressive hydrometallurgical techniques (e.g., highly acidic lixiviant leaching at ambient or elevated temperatures) for Ni and cobalt (Co) extraction. As a precursor to heap leaching, agglomeration of the multi-mineral phase feed particles into robust and porous granules of 4-10 m permeable bed, is essential. In the present work, several basic and applied studies of the agglomeration behavior of real Ni laterite ores and selected oxides and clay minerals (hematite, quartz smectite and kaolinite) which constitute the predominant host gangue phases of typical laterite ores are performed. Isothermal, batch agglomeration tests involving sulphuric acid solution as a binder were carried out to produce coarse, narrow-sized (5 ? 40 mm) granules which were well characterized. The influential role of feed ore characteristics (e.g., mineralogy/chemistry and primary particle size distribution) and binder composition (30 vs. 44% w/w H2SO4) and dosage (15-25 wt.%) in agglomeration behavior and granule properties were examined through several characterization techniques including granule size, compressive strength, bed percolation and re-wetting stability and 3-dimensional micro-structure analyses. Links between feed mineralogy/chemistry and size, binder formulation, agglomeration behavior, curing conditions and final granule properties and structural characteristics are established. The implications of the findings to Ni laterite plant agglomeration for enhanced heap leaching are discussed. Keywords: nickel laterite, complex low-grade ores, agglomeration, heap leaching, micro-structure

Sep 1, 2012

By Yuliy Rubinstein

"The paper presents a analysis of the history and the trends of development of flotation apparatus. The laws of their evolution are stated and the place and role of column flotation are indicated. It is demonstrate development and different design of column apparatus. The major parameters of column cell such as diameter and height are discussed. Options are proposed on optimization of hydrodynamic characteristics of columns with large-capacity cells. High efficiency of columns with cell height of 4-6 m is shown on examples of coal preparation. A new generation of multi sectional column cells has been developed. In the cells are zones with different aerohydrodynamic parameters: combined in the machine are co-and counter- counter flows of phases. The transition from single-chamber column to multi-sectional apparatus makes it possible to create favourable hydrodynamic and aeration regimes in each section of the column dependent on the pattern of material distribution by floatability. Efficiency of application different designs column apparatus uses shown on the example of enrichment of various non-ferrous metals ores and coal. The principles of mathematical simulation of the flotation process are developed. A scaling-up procedure for column cells was based on flotation macro- and micro- dynamics simulation.INTRODUCTIONColumn flotation is considered to be one of the most significant achievement in the field of mineral processing in the end of last century. We cannot but agree with this statement but would like to understand what underlies this success. History of the flotation column can not be considered in isolation from the development of flotation apparatus on the whole. It can be argued that the first attempt to switch from oil flotation to the use of bubbles during flotation was performed Bessel brothers in 1877 (Berlin patent 42 class 22, July 2) and in 1886 (Berlin patent 39,369 May 12). According to these patents, the crushed ore was mixed with oils , hydrocarbons and water. Then the pulp received in this way was heated up to boiling . Air bubbles and steam formed during boiling facilitate the flotation of ore particles coated with oil (first patent) or bubbles been generated by the reaction of lime with acid (second patent). The evolution in the design of the flotation apparatus incorporates the following key stages. Further development is connected with the Francis Elmore’s idea to use gas bubbles received at water electrolysis (UK, 13578; 1904). This method was not introduced then, but much later, in our time and on the essentially new technical basis it found a use for sewage treatment (electroflotation). Gas bubbling under vacuum patented also by Elmore (UK, 17816; 1904) obtained a practical use. It should be noted that the method did not lose its importance till now. The design of the camera has been surely optimized (Glembotskii etal, 1963). A year later A. Macquisten (UK, 26712) developed pressure (compression) flotation. Thus, the H.Sulman, H.Picard, D. Bell’s (US, 853120, May 29, 1905) basic patent and the adjoining T. Goover’s patent 1910 (US, 953746) formed the basis of the first and most important element of modern flotation: flotation with air bubbles sucked in from the environment. In 1914, J.Callow received a patent for on an apparatus where air was sparged through the porous false bottom of the cell ( US, 1104755). Woolen fabric folded four times was fixed on a perforated metal frame to be used for air sparging (Gaudin, 1932). The following year Durrel created the prototype of the injection (ejector) apparatus. The jet aerator made it possible to significantly reduce the size of the bubbles, in comparison with the filter cloth. An apparatus with slurry pre-aeration in an airlift prior to feeding into separation cell was developed Wagner in 1917 (US, 1235083). And finally, the first column apparatus with a counter-current of slurry and air was developed by M. Towne and S. Flynn in 1919(US, 1,295,817). ("

Jan 1, 2018

By F. K. Ikumapayi

An approach to environmental sustainability and improved process economy, in sulphide minerals production is recycling of process water in flotation of complex sulphide ores, although the chemistry of process water may be a critical issue to flotation efficiency. The influence of major components of calcium and sulphate ions in process water on xanthate collector adsorption and flotation response using pure chalcopyrite, galena and sphalerite minerals were investigated by Hallimond flotation, zeta-potential measurement, FTIR and XPS spectroscopy studies, while bench scale flotation tests were also carried out using complex sulphide ores. The impact of the species in flotation was comprehended using deionised water, tap water, process water and simulated water containing equivalent amount of calcium and sulphate species in process water. Hallimond flotation results showed a decrease of chalcopyrite and galena recovery in process water and also in the presence of calcium and sulphate ions in both deionised and process waters, whereas sphalerite does not respond to flotation. The adsorption of calcium and metal ions but not sulphate ions on the minerals is evidenced by zeta-potential data. FTIR and XPS studies revealed the presence of surface oxidized sulfoxy species and surface calcium carbonates on chalcopyrite in the presence of process water and water containing calcium ions, surface oxidized sulfoxy and carbonate species on galena in the presence of deionised water, process water and water containing calcium and sulphate ions, all at flotation pH 10.5, and these surface species influenced xanthate adsorption. The presence of surface oxidized sulfoxy and carbonate species at the sphalerite flotation pH 11.5 were seen in the presence of deionised water, process water and water containing calcium and sulphate ions, but the surface species does not influence xanthate adsorption. Bench scale flotation using two different complex sulphide ores showed that chalcopyrite, galena and sphalerite recoveries are better in process water than tap water. The studies showed that the process water can be recycled in flotation with no detrimental effect on grade and recovery of sulphide minerals. Keywords: sulphide minerals, flotation, zeta-potential, FTIR, XPS

Sep 1, 2012

By Shobhana Dey

A low volatile medium coking coal from Jharia coal field, India was used for this investigation. The proximate analysis of the sample shows that it contains about 25% ash, 21.4% volatile matter and 52.4% fixed carbon. The sizewise ash analysis of -0.5 mm coal indicates that -0.5+0.15 mm fraction contains lower ash (21.9%) than -0.15 mm fraction (29.7%). The flotation characteristics of the -0.5 mm coal were determined by release analysis. The study reveals that recovery of combustible at 15% ash is about 27% and 43% at 17% ash level. The low recovery is due to the presence of high ash in finer fraction. In order to improve the recovery, the -0.5 mm feed was classified into -0.5+0.15 mm and -0.15 mm fractions, and subjected to flotation separately. The recoverable combustible obtained from the release analysis of -0.5+0.15 mm at 15% ash level is 46%. The effect of collector dosage, frother dosage and aeration rate on flotation was studied. The responses of these variables in collectorless flotation of the -0.5+0.15 mm fraction containing low ash were also studied. A lower aeration and frother dosage favored the generation of clean coal with low ash. The ash content in the tailing stream from -0.5+0.15 mm flotation circuit is close to that of the original -0.15 mm fraction. The former is ground to -0.15 mm and the two fractions are processed together. As -0.15 mm fraction contains relatively higher ash, collector aided flotation using sodium silicate was performed to recover the clean coal with 17% ash. The products of the overall flotation circuit having different ash levels were recommended for use in different applications. The reject from -0.15 mm flotation circuit contained 56.4% ash which can be used for fluidized bed combustion (FBC). This eventually leads to complete utilization of coal.

Sep 1, 2012

By N. N. Orekhova, I. V. Shadrunova, N. G. Novikova, N. ?. Volkova

The purpose of the research is scientific substantiation and formulation of strategy and technical solutions of handling liquid wastes of plants producing and refining copper-zink pyritic ores. In the course of research studied are chemical composition of technogenic waters of mining plants as well as water and alluvia of intake river within and outside a sanitary zone of Southern Ural mining plant using inductively coupled plasma mass-spectrometry and X-ray fluorescence analysis techniques. A particular focus is made on microcomponent composition. Novel data on Cd, Li, Be, Mn, Co, Cu, Zn migration with technogenic flows and accumulation of these elements in alluvia is obtained. It is showed that extraction of valuable components from technogenic waters is a novel problem for refiners that can be solved only in cooperation with mining industry ecologists. Laboratory research of selective copper and zink extraction into corresponding practical products by galvanocoagulation and sulphide precipitation is carried out. Common factors of phase formation are studied using physicochemical modeling, X-ray phase analysis and electronic microscopy. Methods of intensification of processes and increasing of extraction ratio of metals in products are elaborated. A technology of comprehensive processing of undersoil waters is proposed. Enlarged laboratory and pilot plant tests of technological solutions for protecting hydrosphere and extracting metals from mine waters carried out on several plants of UMMC-Holding Corporation showed a possibility of obtaining additional products having weight content of metal which is profitable for consequent metallurgical processing and purification of waters to comply with quality standards. A possibility of transformation of technological chain depending on season variability of water quality is put behind the designed technological schemes.

Jan 1, 2018

By T. Fujita

The incinerated bottom ash includes titanium oxides and a small amount of chromium oxides. Initially, 89 % of chromium was removed from ash at magnetic flux density at several stages of wet magnetic separation from 0.05 T to 6 T. The bottom ash from an industrial waste incineration process includes about 10 % of TiO2. The minerals that contain titanium are rutile and perovskite. These minerals are paramagnetic and show low magnetic susceptibility, therefore, the high magnetic field strength, created by a superconducting magnet, is necessary to capture these minerals. At the first stage of separation, a magnetic field strength of 6T was applied in order to attract the particles that contain iron oxides to the higher magnetic field region. At the second stage of separation, the magnetic capture rate of weekly magnetic particles decreased with increasing the magnetic susceptibility of the aqueous solution (i.e. the medium for dispersing the particles) in order to separate the highly magnetic materials. The para-magnetic salt such as ferric chloride was dissolved in the water to increase the magnetic susceptibility of the medium. After a two-step wet HGMS with superconducting magnet, the grade of TiO2was increased from 10 % to 28 % with a recovery of 64 %.

Jan 1, 2014

By Jan Svoboda, Atsushi Shibayama, Toyohisa Fujita, Toshio Miyazaki, Kenji Murata

"The electrical disintegration (ED) method and disintegration by underwater explosion were investigated as new fragmentation techniques for the kimberlite ore and tungsten scrap of superalloy (carbide bit). The results of various breakage tests demonstrated that both fragmentation methods as new disintegration techniques for recycling were able to liberate various components of materials of different resistivity and elastic impedance.SUMMARYThe breakage of the kimberlite ore from South Africa (sample size: 15 mm x 15 mm x 6 mm) was achieved by the ED method. A relationship between the sample size, voltage, the electrical current and the energy needed for the disintegration was found from the experimental results. Kimberlite exhibited a high degree of breakage, when the high voltage of 60 kV and the pulse current of approximately 5000 A were applied to the sample by the generator during 0.2 microseconds (Fig. 1)."

Jan 1, 2003

By Irena Grigorova, Tashka Ignatova, Ivan Nishkov, Andrian Valchev

"Feldspars used by ceramic and glass industries as fluxing agents are mainly obtained from high quality feldspar deposits. The demand for feldspar as raw material for industrial applications especially in ceramic manufactures is continuously increasing. However, due to the depletion of those deposits, the research activities related to the recovery of feldspar from the lower grade feldspar deposits and feldspar bearing rocks such as pegmatite, granite, arkosic sandstone and syenite have been intensified in the last two decade. In Bulgaria, the main deposit of arkosic sandstone is located in the area of Shumen town, NE Bulgaria. In Srednya deposit arkosic sandstones are found in Upper Cretaceous sediments (Santonian). In this formation, there are two major industrial minerals - feldspar and quartz. They may be of economic value and possibly suitable for commercial uses. The main purpose of the present study was to investigate the beneficiation and upgrading processes of Srednya deposit arkosic sandstones. In a laboratory scale it was studied the possibility to obtain the feldspar concentrate and quartz sand from arkosic sandstones. Particle size distribution, chemical and mineralogical compositions of quartz-feldspar sands were determined. The bench-scale tests using the KOALIN AD laboratory experimental facilities were conducted. Many processing techniques were tested: disintegration, washing, sizing, carbonate flotation and feldspar flotation. The experimental results show that there are possibilities to obtain the silica sand with low content of Fe2O3 - below 0.02 % and potassium feldspar with content of K2O > 14 %. A new technology for recovery of feldspar and silica sand from arkosic sandstone was developed."

Jan 1, 2014

By Wei Sun, Chengwei Li, Zhiyong Gao, Yuehua Hu

"Grinding for mineral liberation is a prerequisite for a successful flotation separation. Different grinding media produce mineral particles with different morphologies and surface properties. In this study, the surface physicochemical properties of fluorite particles produced by ball and rod mills were systematically investigated through single mineral flotation experiment, wettability measurement, X-ray diffraction (XRD) test and scanning electron microscopy (SEM) observations. The XRD observations reveal that the surface exposure degree for both mill particles follows the order {111} > {110} > {100}. The difference lies in that the rod mill ones have a higher exposure of more reactive {110} and {100} surfaces, leading to a stronger interaction with the collector. The difference also leads to their higher elongation and lower roundness values of rod mill particles which are beneficial for the particle-bubble attachment by shorting the induction time. The wettability and flotation results show that the rod mill ones have a lower critical surface tension and a greater hydrophobicity when treated with the collector solution and accordingly perform a higher flotation recovery. This work, for the first time, revealed the importance of the exposure of crystal surfaces in determine the shape factors and reactivity of the mineral particles and will help provide guidance for optimizing flotation separation and particle surface modification. INTRODUCTIONFluorite (CaF2) is the most important source mineral for producing F-based chemicals and materials which are widely used in industrial, environmental, and medical fields [1, 2]. In ore deposit, there are two kinds of occurrence forms of fluorite mineral. Firstly, the fluorite mainly coexisted with the gangue minerals like calcite (CaCO3) and quartz (SiO2). Because of their similar density and fine-grained dissemination in ore deposit, ball mill grinding before flotation separation has been widely applied to produce relatively fine particles [3]. Secondly, the fluorite is often associated with other valuable minerals with higher relative density such as scheelite (CaWO4) and cassiterite (SnO2). Due to their obvious density differences and coarsely grained distribution in ore deposit, rod mill grinding before gravity separation has been usually used to produce more uniform particles and avoid over-grinding [4-6]. After the gravity separation, a flotation separation is also employed to beneficiate the fluorite [7]."

Jan 1, 2018

By Patricio Berrios, David Barriga, Peter Amelunxen, Gerson Sandoval, Roger Amelunxen

Laboratory test equipment and methods have undergone relatively little change since their introduction in the 1950’s. The Denver sub-A cell is still by far the most commonly used laboratory batch cell, but bottom-driven and instrumented cells are beginning to appear. Test procedures have also changed little over the past 60 years, and most engineers continue to rely on empirical models for predicted plant scale performance from laboratory scale tests. This approach is problematic, because changes in the froth phase characteristics in the lab hamper the reliability and reproducibility of the empirical extrapolation to plant scale. In a previous work, the authors reported on the impact of froth recovery at the laboratory cell, showing that variability in the froth recovery can lead to significant error in the modeled kinetic rate constant unless it is properly accounted for in the scale-up model. In this work, we review the role of hydraulic entrainment in the lab cell, and how variability in particle specific gravity, shape factor, and froth residence time can impact the entrainment recovery.

Jan 1, 2014