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By D. P. Chakraborty

Joda East Iron Mine, one of the captive iron ore sources of Tata steel, located in the state of Odisha in eastern India caters to approximately 45% of the iron ore requirement of the Jamshedpur Steel Plant. The iron ore occurring in the mine having high in iron content along with high in alumina. Clay and gibbsite are the predominant mineral phases present as surface coating, fracture filling and/or free occurring and are responsible for alumina content higher. Alumina in iron ore impacts the techno-economic performance of a steel plant by impacting sintering and blast furnace productivity. The impact is even higher when it comes to fine ore used in the blast furnaces in the form of sinter as it constitutes a major portion of the blast furnace burden. Therefore, it is beneficial to upgrade iron ore in the mine head and to reduce alumina before it is subjected to agglomeration. Mineralogical test works reveal, that alumina in iron fines is mainly associated with the clay attached to the hematite particles, either free or interlocked to a very fine size. The paper describes the efforts made to reduce alumina in the iron fines in Joda East processing plant, without much of capital investment for a very sophisticated fines beneficiation circuit. In this process, a suitable dispersant was added in the plant that dispersed the masked slime coating over the iron ore fines, thereby making a better quality iron ore fines with reduced alumina content. The alumina in fines improved by 0.2 units? means from a label of 2.4-2.6 % reduced to 2.2-2.4 %. With this initiative, not only the primary objective of alumina reduction is met but also it has given substantial benefit in reduction of silica and as well as moisture in product. This moisture reduction also has given bottom line impact by reducing idle freight and royalty.

Sep 1, 2012

By Z. H. Zhang

Shizhuyuan is a world-class WO3, Mo, Bi and CaF2 poly-metallic deposit; it has rich reservation, but great difficulty in ore?s processing; thereby, for many years, it has been the target problem of beneficiation technologies. This paper, while briefly reviews its main scientific and technological advancement, pays special attention to the complete set of new technology and technical index achieved in recent years, which is characterized by using full-floatation flow-sheet as the backbone flow-sheet, explores some key factors influencing tungsten floatation, and presents a brief introduction to such new equipment as flotation column and comprehensive utilization of fluorite.

Jan 1, 2014

By Fangming Liu

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

Sep 1, 2012

By Takashi Furuyama, Sukeyuki Mori, Takafumi Okuma, Norio Hashiguchi

"In order to achieve a high recovery of particles finer than 10µm, three types of dry Tower Mill (VD-1, KD-1, KD-2 and KD-3) have been developed. These mills differ from each other in the size of the comminuting part, the inside diameter and shape of the classifying part and the system involved in the collecting process. The last version (KD-3) of tower mills in which the comminuting and classifying operations has been separated, can produce particles finer than 10µm from a limestone ore sizing from 420 to 3360µm. In this tower mill, products in comminuting section are blown up and transported into the classifying column, made of an inverted cone on top of a cylinder, before they agglomerate and settle down. Fine particles are deported and recovered in a cyclone with a central spiral ribbon.Previous studies on the grinding efficiency of the tower mill KD-3 have shown how the maximum size of collected products increased with the airflow velocity, disturbing in the same way a smooth regulation of the grinding operation with the tower mill KD-3. A complete knowledge of factors that influence the maximum size of collected products is needed, therefore, to increase the efficiency of the grindingclassifying operation and ensure a better control over the collected products. The present study deals with this issue and, assuming that the structure of the classifying column could be one of these factors, its internal structure was modified (insertion of vertical plates, cone or horizontal nets) before carrying out comminution tests that would establish a relationship between the inward shape of the column and the maximum size of collected products. It was found that the weight of products collected in the cyclone decreases when a cone or some horizontal nets are inserted inside the column. At the same time, the weight of products collected in the column increases. This is due to the fact that coarse particles blown up from the comminution section collide with the base of the cone or the nets and settle down the bottom of the classifying column. Therefore, the cone and some horizontal nets inserted inside a classifying column, have the particularity to stabilize the maximum size of particles (15.1-17.5µm and 8.4-11.3µm) in the cyclone even when the airflow velocity in duct increased. These tools could of great help in the production of particles of definite size to fit for instance the paper industries requirements (production of limestone material sizing - 10µm as paper filler)."

Jan 1, 2003

By Rhulani F. Maluleke, Francis W. Petersen, John H. Marsh, Johann de T. Steyl, Allan Nesbitt

"Pressure leaching of chalcopyrite and nickeliferrous pyrrotite at temperatures between 105 and 200 ºC has been proposed as a potentially viable route for the extraction of mineral elements from sulphide concentrates. In general, these concentrates contain iron, and the economic success of the processes is partially dependent on the choice of the environmentally acceptable iron-removal technique. One of the most widely used methods for the removal of iron from sulphate liquors is precipitation as hematite, goethite, or jarosite. The nature of the iron precipitate formed, dictates downstream dewatering and residue treatment and disposal options. However, a better understanding of iron precipitation under the defined process conditions would consequently be of benefit in process design and optimization.This study investigated the precipitation of iron in the autoclave at temperatures between 105 and 200 ºC. The effects of temperature, acid concentration, iron concentration, and the presence of other metal cations on the nature and composition of the precipitates were determined."

Jan 1, 2003

By Kwan Ho Kim

In this study, free fall tests are conducted with the objective of understanding the breakage properties of waste concrete for the guide of the direction of the better comminution process. Waste concrete of 75mm×53mm is tested at various drop heights with or without heat pretreatment. Test results indicate that a block of waste concrete does not break by free fall, but eventually breaks by repeated free falls. The number of free falls required for complete separation of large aggregates from the cement mortar considerably reduced when the samples were heated at 400?. Therefore, a great energy saving can be obtained when heating the waste concrete prior to crushing. The energy saving was found to be dependent on the height of free fall but in all cases, was still large enough to offset the additional energy required for heating. Also, it was found that the heat pre-treatment gives an additional advantage in that it produced cleaner recycled aggregates. This may result from easier detachment of cement mortar from the aggregates due to weakening of bonding forces by heating. By analyzing the size distribution of the crushed product, a free-fall breakage model is developed using the particle breakage ratio and the breakage pattern. The developed model can be used to predict and to analyze waste concrete processing circuit.

Jan 1, 2014

By M. Roy

Coke combustion during sintering process is significantly governed by coke breeze size distribution, which in turn affect sinter quality i.e. sinter granulometry, Tumbler index, Reduction Degradation Index and Reducibility Index of sinter. To know the effect of microfines of coke breeze on sintering process parameters, pot sintering tests were conducted and it was found that when microfines are eliminated and optimum coke size (1-3mm) is used yield of sinter increased by more than 7%. Similarly productivity increased by 9%, the strength of sinter i.e. ISO Tumbler Index increased by 2.3% and +10mm sinter size increased by 5.5%. Controlling of microfines during crushing and by improving crushing index will result in improved quality and productivity of sinter with lesser amount of coke breeze. This paper describes that how to optimize solid fuel i.e. coke breeze consumption in sintering process through granulometry control. Keywords: iron ore sintering, coke breeze granulometry, productivity of sinter, quality of sinter

Sep 1, 2012

By H. M. Yang

Structural alteration of pyrophyllite during mechanical activation in a planetary mill was investigated by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. Mechanochemical effect markedly promotes the decrease in reflection intensities with increasing the grinding time. Prolonged grinding causes the pyrophyllite to become the amorphous structure. It can be indicated that pyrophyllite is very susceptible to alteration by grinding. Crystal size (d006) of pyrophyllite appears to be a limit after 2h grinding. IR spectroscopy analysis shows a little alteration in the bands of pyrophyllite after mechanical activation. The results indicate that the ordered structure of pyrophyllite is destroyed and lattice deformation occurs. Porous silica was then successfully prepared via leaching the mechanically activated pyrophyllite. Pyrophyllite was first ground for 6 h. Ground samples were subsequently leached with 4 M hy-drochloric acid at 80 °C for 2 h to produce porous silica with specific surface area of 188.1 m2/g, total pore volume of 0.18 mL/g and average pore size of 3.9 nm from N2 adsorption analysis. Otherwise, the porous silica obtained from direct leaching of the original pyrophyllite only has a specific surface area of 4.3 m adsorption analysis. 2/g and total pore volume of 0.03 mL/g. It is inferred that grinding is favorable for the formation of microstructure pores. It offers a simple and convenient route for the preparation of porous materials from natural minerals.

Jan 1, 2014

By Muammer Kaya, Sait Kursunoglu

"Energy is the major concern for society. It is expected that developing country economies and populations will grow and consume more energy. Interest in nuclear power is rising, while the world looks for non-depletable energy source that will not contribute to global warming. However, it still has concerns of nuclear proliferation, radioactive waste and safety. It is necessary to overcome these concerns if nuclear energy is expanded to developing countries. Thorium (Th) utilization as nuclear fuel will be an opening key of these difficulties because Th produces less Plutonium (Pu) and less radioactive waste with enhanced safety. Research into the use of Th as a nuclear fuel has been taking place over forty years, through with much less intensity than that for uranium (U) or U-Pu fuels. Nuclear industry is currently using only 0.7% of the available energy from mined U. With huge resources of Th and relatively little U, Turkey has made utilization of Th for large-scale energy production a major goal in its nuclear power programme. Thorium fuel is plentiful and inexpensive. Energy is major concern for developing Turkish society. Turkey, today exports more than 70% of its energy as fossil fuels. In the last 50 years, Turks are skeptical, anxious and indecisive about having nuclear energy for electricity production. In the last 10 years, Thorium is brought into Turkish government’s attention and national discussion as a new, safe, clean, affordable, CO2-free, alternative, strategic and domestic nuclear energy fuel. Turkey recently contacted four VVER-1200 type Russian Nuclear Power Reactors using U as a fuel in Akkuyu (Rosatom) and another four units will be established in Sinop in the next decade by Japan (Mitsubishi-Westinghouse). Turkish nuclear programme must envisage use of domestic Th as a fertile material. This paper briefly reviews the developments of Th-fuel cycle for nuclear energy from global and Turkish perspectives. Previous Th reserve development and recovery studies from Turkish bastnasite ore are summarized in this paper."

Jan 1, 2014

By I Brum

Brazil and Colombia have large reserves of coal, those reserves in Brazil are located predominantly in the south and Colombia the main reserves are located in the north. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently, these countries are developing projects and partnerships aiming to qualify this mineral resource, adding quality to the final product of the processing plants. In this scenario the processing of Brazilian and Colombian coal in flotation columns appears as a promising alternative, having been successful in mineral systems containing fine particles This paper aims to study the overall process of column flotation for a specific Brazilian coal and a specific Colombian coal. The material used in this study consists of fine coal from Brazil (Copelmi) and Colombia (Cerrejon). The objective is to recover carbonaceous matter and reduce the ash and contaminants grade. The two coals were floated using a negative bias in a 5 cm diameter conventional flotation column of 5 m high. Flotation parameter investigated included air velocity in the range 0.6 to 1.5 cm/s. For all runs, a constant negative bias of -0.25 cm/s and a pulp concentration of 8% w/w were used. For Cerrejón coal, 300 g/ton of frother and 907 g/ton of collector was used, whereas for Copelmi coal, 600 g/ton of frother and 1815 g/ton of collector was employed. The frother was a commercial Aerofroth 65 (AF65), whereas the collector was Kerosene. For the Colombian coal, in general, yield, organic recovery, ash recovery and water recovery decreased with the increasing air rate. However, for Brazilian coal the air rate had no significant effect. For Colombian coal, the highest yield (60% w/w) and organic recovery (69% w/w) were obtained at the lowest air rate (0,6 cm/s). Keywords: negative bias, column flotation, coal

Sep 1, 2012

By Chuansheng Luo

If lead-zinc ores have high oxidation rate, separation of lead and zinc is very difficult. This paper studied the technology of preferential flotation by the coarse grinding and re-grinding. The lead concentrate grade is 51.40% and the lead recovery is 62.83% when feed grades Pb 1.74% and Zn 6.46% with oxidation rate being 13.75%. At same time, the zinc concentrate grade is 50.07% and its recovery is 90.01%.

Sep 1, 2012

By Ralph J. Holmes, Victor Sharp, Steven J. Spencer, CSIRO Minerals, Kevin J. Davey, Jonathan J. Campbell, Peter L. Phillips

"Improved measurement tools for monitoring and control of AG/SAG mill performance have a high level of interest in industry. Historically, acoustic emission monitoring has been widely used on SAG/AG/ball mills and hydrocyclones to provide new information on the conditions inside these devices affecting their performance. The current work was focused on a new technique using surface vibration monitoring of a number of pilot-scale and production-scale AG/SAG mills to yield insights into the events occurring in the mills. The development of relationships between signal analysis outputs and mill operating conditions can be used for soft-sensor measurement of mill process variables. The technique used an array of accelerometers mounted on the mill lifter bolts linked to a fast data acquisition system which monitored the surface waves generated during operation. Details of the system are presented. Mill operating variables were adjusted systematically to provide a wide range of operating conditions for surface vibration signal collection. The experimental approach is discussed.The signals acquired during the experiments were analysed using a range of techniques. The results show that strong relationships exist between measured vibration power (both total power and within certain frequency bands) and mill load level/power and mill speed. A new method for extraction of power spectral density and band power information on features of interest in a mill rotation cycle is also presented."

Jan 1, 2003

By Lilong Huang, Xiang Zhao, Yuan Long, Li Shi, Guowang Zhang, Xiao Xiao

"Vertical stirred mill is expected to upgrade the iron concentrate by further size reduced efficiently. The tests for fine grinding of iron ores from Baiyun Boyu iron ore, Baogang Goup, iron contained tails of Cu-Pb-Zn ore in Wanguo ore, Xiaoshalong iron ore in Qinghai were conducted in this paper. The data of appropriate grinding fineness, optimum grinding conditions and energy consumptions obtained from the test were used to select appropriate scale of the vertical stirred mill, optimize the parameters of the grinding process and upgrade the iron concentrate of the iron ore dressing plant or design the new ore dressing plant. Based on the laboratory tests, industrial system of regrinding and magnetic separation with vertical stirred mill as the regrinding mill in micro-fine grained iron concentrate upgrading has worked out very well. The grade of Fe in iron concentrates has increased to about 65.0% (by 4.0~6.5 point percent) when the iron concentrates were reground to designed fineness and the specific energy is 5.0~7.1kWh/t. The system of regrinding and magnetic separation is proven to be eco-efficient in iron concentrate upgrading."

Jan 1, 2014

By F. S. Hoseinian, K. Filho, D. Deglon, T. Souza, M. Safari

"This paper investigates the reverse flotation of hematite in three laboratory flotation cells with very different contacting environments. The main objectives are to investigate the recovery of coarse quartz by flotation and fine hematite by entrainment. The laboratory flotation cells used were the mechanical, oscillating grid and pneumatic cells. The effect of froth height and solid concentration were investigated in the mechanical and pneumatic cells. The effect of impeller speed and energy input were investigated in the mechanical and oscillating grid cells. Froth height results show that coarse quartz particle recovery decreases almost linearly with increasing froth height due to increased detachment of coarse quartz particles in the froth. Fine hematite particle recovery also decreases almost linearly with increasing froth height due to decreased water recovery and associated entrainment. Agitation/energy input results show that coarse quartz particle recovery increases with increasing impeller speed to an optimum, after which this decreases dramatically. The increase is due to improved gas dispersion, generation of smaller bubbles and increased bubble-particle collision and attachment. The decrease is due to significantly increased bubble-particle detachment at higher impeller speeds. The recovery of coarse quartz particles in the OGC is higher than that in the mechanical cell with an optimum at a much lower energy input. Solids concentration results show that both mass recovery and water recovery increase with increasing solid concentrations. The pneumatic cell achieves higher mass recoveries and lower water recoveries than those in the mechanical cell at equivalent solids concentrations and operating conditions. INTRODUCTIONFlotation is a selective process for separating different minerals from each other. The flotation separation efficiency depends on the recoveries of the mineral species by both true flotation and entrainment (Neethling and Cilliers 2009; Wang et al. 2015). Both chemical variables and hydrodynamic conditions within the flotation cell affect the recovery and selectivity of the flotation process. Cationic reverse flotation of hematite is a common method for selective separation of quartz from iron ores to produce pellet feed. The presence of coarse quartz particles in the tailings and fine hematite particles in the concentrate are two major challenges in the reverse flotation of hematite (Vieira and Peres 2007)."

Jan 1, 2018

By I. Nishkov, I. Grigorova, N. Valkanov, M. Ranchev

The processing of sulphide ores with variable and complex mineral composition and physical properties, such as those processed by two-stage selective flotation scheme in “Erma reka” concentrator, Minstroy Holding JSC, requires excellent selectivity in order to achieve acceptable concentrate grades. The lead-zinc ores from the hydrothermal lead-zinc deposits mainly contain galena (PbS), sphalerite (ZnS), pyrite (FeS) and chalcopyrite (CuFeS2), as well as non-metal minerals such as quartz, carbonates and clinopyroxenes skarns. One of the main impurities present in sphalerite is iron, which is known to be detrimental to the rate of sphalerite flotation and its recovery. The results from the conducted laboratory and industrial tests, presented in the previous study, showed that it is possible to depress the iron rich sphalerite by adding MINFIT® (modified sulfur-oxy depressant) at the pH of approximately 9.5 in rougher lead flotation circuit, leading to reduction of zinc sulphate consumption and complete elimination of cyanides from the flotation process. Furthermore, the consumption of copper sulphate, which reactivates the surface of the zinc minerals, was significantly reduced. Consequently, the optimisation of the reagent regime in the Erma reka concentrator, led to notably improved qualitative (grade, recovery) properties of the final lead and zinc concentrates. Moreover, when comparing the reagents consumption for 2014 and 2016 – when the processing plant have been applying the new optimized reagents regime, comprises the use of MINFIT as the primary depressant, the following results have been achieved: ZnSO4 decreased by 30%; CuSO4 consumption decreased four times and full rejection of cyanides from the process. Finally, this paper provides a state-of-the-art review of the obtained results during the period of application of the new flotation reagents regime in the Erma reka concentrator, Minstroy Holding JSC.

Jan 1, 2018

By Choi Sang-Ken, Chung Hun-Saeng, Kim Byoung-Gon, Lee Jae-Jang, Park Chong-Lyuck

"Graphite has unique properties such as high thermal resistance, low thermal expansion coefficient, and good thermal and electrical conductivity, and is often utilized as coating materials for electrical conductors, TV Brown tubes, electromagnetic shields, and so on. Additionally, its excellent lubrication property is widely used in oil and solid lubricants. Finely ground graphite particles in the sub-micron range are commonly used for these applications.Sub-micron fine graphite particles are typically prepared in liquids by vibration ball mills. However, it is known that the wet process takes long periods of grinding time like 24 hours or more and requires a series of subsequent highenergy operations such as de-watering, drying, regrinding and classification. On the other hand, there would be numerous advantages if fine grinding could be done effectively in dry atmosphere. However, since crystalline graphite has a layered structure giving a high lubrication property, its dry grinding, especially when obtaining sub-micron size particles, is extremely difficult. The shape of the graphite particles is also important for its utilization since particles with flaky shape can maintain relatively high electrical and thermal conductance as well as lubrication ability. Therefore, it would be necessary to reduce the size of graphite particles into fines with flaky shape while grinding proceeds. Dry grinding characteristics of natural graphite under various atmospheric conditions with gases using different mills were studied, and fine flaky particles by grinding the graphite intercalation compounds and the exfoliated graphite were produced. However, there were no sufficient investigations on the size reduction of natural graphite at low atmospheric pressures in attritional milling conditions. The main purpose of this paper is to provide sub-micron fine grinding characteristics of natural crystalline graphite at various degrees of low atmospheric pressure, and to discuss the size reducing models in an attrition mill"

Jan 1, 2003

By Jian Zhang, Yongfu Yu, Fuguang Zhang, Liping Che

There is one large-scaled iron ore deposit in Inner Mongolia of China, but it is very complex which includes about 170 types of minerals and 71 elements. The hematite, magnetite are mainly iron ores. It is difficult that the iron mineral can be separated efficiently by common dressing methods due to the complexity, and the iron concentrates in the mineral processing factory contains many foreign substance such as K, Na and Si so that the process in iron mill is influenced because of the foreign substance, so it is vital reducing the foreign substance.

Jan 1, 2003

By E. Barsky

"The aim of separation is to obtain two products that are as distinct as possible from each other. It is currently believed that the most objective criteria for the quality of a separation are the Hancock criterion and the entropy criterion.1. Hancock criterion:- for yield of fine product"

Jan 1, 2003

By Roberto C. G. Oliveira, Scott C. Brown, Brij M. Moudgil

"The wettability or surface energy of particle surfaces dictates a number of multiphase ensemble interactions that have a significant impact in mineral processing. Dispersion, bulk powder handling and flotation are just a few of the processes that are largely influenced by the degree of hydrophillicity or hydrophobicity on particulate surfaces. Because of the importance of surface wettability, a number of simple, precise and accurate techniques for accessing surface wettability or contact angle on macroscopic flat surfaces have been developed. However, these techniques cannot be directly applied to the particulate surfaces that are often in query. Though a number of techniques are available for accessing the wettability of particulate surfaces, these methods are either relative, application specific or prohibitively tedious. In the present study, key features of existing techniques are combined to formulate an improved method to delineate particle wettability that is simple, versatile and capable of providing reproducible measurements in an industrial environment.Through the use of an inert adhesive and an inert macroscopic surface as a support, it is illustrated that precise measurements of particle wettability are obtainable under suboptimal or ‘shop floor’ conditions. The measurement of the maximum external meniscus height formed between a test liquid and a particlecoated rod is employed to estimate phenomenological contact angles on particles ranging form a few nanometers to several hundred microns in size."

Jan 1, 2003

By Markus Dammers, Christopher Robben, Hermann Wotruba, Christian Schropp

"In most underground mining processes the entire extracted ore is transported from underground workings to surface processing plants for separation of valuable minerals and gangue material. Most of the transported material consists of barren rock with negligible metal content, especially for low grade deposits, such as in the copper or gold metal ore mining. Increasing mining depths result in higher costs for transportation and hoisting. Therefore, rejecting waste rock as soon as possible from the material stream gains importance. The concept of resource to product integration in the form of earliest waste rejection in combination with subsequent backfilling follows the philosophy of ‚leaving waste underground?. Implementing mineral processing underground can lead to less required mass movement to surface, hence reducing transportation and hoisting costs. At the same time, rejected waste can be used as backfill to increase extraction rates by reducing pillar volumes. In the mill, a stable high grade feed leads to decreased specific operating and investment costs as well as increased productivity and recovery. These effects as a whole have a large potential to reduce cut-off grades so that resources can be turned into reserves. Within the I²Mine (Innovative Technologies and Concepts for the Intelligent Deep Mine of the Future) project of the European FP7, investigations are carried out by the Unit of Mineral Processing of RWTH Aachen University, the Institute of Mining Engineering I and TOMRA Sorting Solutions | Mining. One aim of the cooperation is to develop new concepts for a comprehensive integration of near-to-face processing in combination with backfill into the overall underground mining process. Effects on up-, down- and side-streams are investigated to prove the potential of resource to product integration in comparison to common underground mining systems and processing methods."

Jan 1, 2014