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By F. Q. Dong

According to the principle that should be originated from nature, compatible with nature, used in nature and back to nature and based on conception of designing of eco-material, the author combined the ideas of material, environment, zoology and healthy. Properties of natural mineral materials were used to produce micro-aggregate elements by bionic method, so its components and function could accord with living environment. Eco-mineral functional materials which can adjust, purify and optimize the microclimate were reviewed. The authors pointed out the multifunction, com-pounding, the compound characteristics and integration regularities of micro-aggregates. It was the first time in the world to put forward the ?gene? technique or ?material chip? technique of manufacturing function micro-aggregates and eco-function elementary materials. The results of this re-search supported by the national ?863? Hi-tech Project, mainly including the high-efficient air purifying mineral compound material indoor, the clay elementary antibacterial materials, the masonry cement/coating/putty/compound with preventing radon radiation, environmental friendly composite functional coatings, mosquito repellent and healthcare material and zeolite-based energy-saving composite materials, were introduced. Finally, the foreground of mineral materials in the field of future advanced eco-friendly materials was also discussed.

Jan 1, 2014

By J. E. Gebhardt

Progress is reported on capturing the effects of gangue chemistry in the context of a comprehensive stockpile heap leach model for leaching copper sulfide ores, employing leading edge computational fluid dynamics (CFD) technology. The stockpile is a complex multi-phase process, comprising of a solid porous media, with complex fluid flow, gas and liquid phases, competing solid-liquid reactions, dissolution of minerals and transport through the heap. The model accounts for many of the challenging physical and chemical features of the heap, including transport and reactions kinetics for the important copper and iron sulfide minerals, ferrous oxidation, bacterial effects, thermal energy, acid and sulfate balances. In this contribution, the model has been extended to incorporate dissolution of various species from gangue reactions and precipitation of hydronium and potassium jarosite, ferric hydroxide, alunite, and gypsum. The effect of aeration on the simulation of a copper sulfide heap leach is provided as an example.

Sep 1, 2012

By Ashutosh Shandilya

Froth flotation is a selective separation process and rarely used for beneficiation of limestone in the world as compared to other minerals and also mostly known conventional methods of up gradation of ROM including wobbling, selective mining, sorting, preblending etc. Limestone is mainly used in the manufacture of cement, steel and chemical industries. High grade limestone deposits are depleting day by day and the requirement of the industries have to be met by beneficiating the low grade limestone deposits in the world. And because of marginal quality of limestone, it cannot be directly used in cement industry. At ACC Madukkarai cement works, Coimbatore, Tamilnadu, full fledged mineral beneficiation process is adopted to enhance the quality of low grade lime stone from 38-42 % CaO to 45-47 % CaO and silica reduced from 19-22 % to 11-13 % by use of oleic acid (commercial grade and vegetable origin) 0.38 kg/ton of limestone and caustic soda 0.05 kg/ton of limestone. Keywords: OK-8 Cells, Froth flotation process, Beneficiation studies, Low-grade lime stone, Oleic acid, % solids, Pulp density, Ph, Iodine value, saponification value, Denver cell

Sep 1, 2012

By M. Bhartia

India is the 5th largest producer of steel in the world and is slated to produce more than 180 Mt by 2020. Expectedly about 50 % of this would be through the Blast furnace route and the rest through Sponge iron / DRI route. Considering that there will not be any major change in iron making technology by that time, the Blast operation would require lump ore (10-40mm) with around 64% Fe grade and sinter fines (<10mm) with 60% Fe (min) as its feed. DRI process would need calibrated ore of size 5-18 mm as the most suitable size of feed. It is also expected that of the total requirement of ore for the DRI route a significant part would be DRI pellets. In India, there is considerable debate going on regarding the technology to be adopted for the processing of iron ore and there is a lack of clear consensus. The above scenario indicates that the processing requirement of iron ore in the country would involve both washing technology as well as beneficiation technology. CDE Asia Ltd is in the forefront of iron ore processing in the country and the experience gained by the company over the last few years of functioning has led the company to believe that route to be adopted depends on the end product requirement and the starting grade of the feed. Keeping in mind the nature of the feed required for the Blast furnace & DRI operation; it is obvious that good washing technology would be highly beneficial to the iron ore industry. Depending on the grade of ore available the limits of washing will be decided and equipment for lump ore beneficiation such as jigs could be incorporated into the washing circuit. Scrubbing of ore either before washing or selectively scrubbing the lumps could be necessary. Very low grade ore and jig rejects would be required to be totally ground and beneficiated for the production of pellet feed in order to utilize the iron ore resources entirely. Another source of ore for pelletisation would be slimes generated from the washing process as well as the huge quantities already available in the tailings dams in the operating mines. Deslimimg and magnetic route of beneficiation could release at 30-40% of the Fe locked up in these tailings ponds/dams. The paper describes the concept with examples from operating plants and proposes how the adoption could be engineered through test work and proper plan of integration. Keywords: washing, beneficiation, iron ore, lumps, sinter fines, pellets, jigs, screens, evowash, nanowash, thickeners, log washers, drum scrubbers

Sep 1, 2012

By Robin J. Batterham

The Bologna Process started in 1999 with a declaration signed by ministers from most European countries. As of 2012, the Bologna Process now has 47 participating countries (EHEA 2012). Overall, the Bologna process has demonstrably changed higher education in many countries to allow for considerably more flexibility in course offerings. Keywords: bologna model, education

Sep 1, 2012

By F. Q. Cheng

Despite the successful industrial practice to recovery KCl by flotation, the adsorption state of collectors at KCl salt surfaces is still not fully understood. In this paper, the captive bubble contact angle measurements at KCl and NaCl crystal surfaces in their saturated solutions are reported. The influence of different collectors and their concentration are considered. The results show that both cationic and anionic collectors produce a hydrophobic state at the structure breaking KCl salt sur-face, with finite contact angle values of between 30o and 40o. In contrast, the contact angle at the structure making NaCl salt surface is zero at all collector concentrations, suggesting that no collec-tor adsorption occurs, a supposition that is supported by results from molecular dynamics simulation (MDS). Further, it appears that the presence of surface defects such as edges and corners promote the adsorption of collectors at the KCl surface, and that the flotation is achieved by bubble attachment at the edges/corners of KCl particles with the formation of aeroflocs.

Jan 1, 2014

By A. K. Suri

India plans to increase the nuclear power share in overall energy-mix to about 30% by 2032 using both indigenous and imported reactor technologies. In the immediate time-frame, it is envisaged to generate 10000 MW electricity by PHWR technology by 2020 using indigenous uranium resources. This necessitates setting-up of new uranium mills and augmenting the existing resource, mining and milling capacities. This paper describes the current status and future R & D needs towards achieving the targeted demand of yellow-cake. Keywords: uranium, hydrometallurgy, leaching, yellow cake

Sep 1, 2012

By Sanchita Chakravarty, Sumantra Bhattacharya, Divya Jyoti, A. K. Mukherjee, Soni Jaiswal

"Release analysis is independent of collector and frother dosage and type, but it is primarily influenced by the degree of liberation or “state of release of the sample”. The shape of release curve is an indication of the degree of liberation. This paper briefs about the effect of reagent combination, particle size and surface characteristics on the release analysis of difficult-to-clean LVC coal.Release analysis of three LVC coal fines obtained from two different coalfields of India was carried out at three different size levels such as -0.5mm, (-0.5+0.1) mm, and -0.1mm. The collectors used were n-dodecane and commercial diesel oil. Incomplete liberation of coal fines even at a size of -100µm, corroborated by photomicrographs of ROM and clean coal macerals, in a great measure reduced the flotation-based cleaning potential of the fines. FESEM images of fines reveals that the adherence of ultrafine onto the surface of relatively coarser particles reduced the clean coal recovery. The results obtained also appear to be coal, reagent combination and, particle size and particle surface specific. Only one coal indicated the liberation as is usually expected for -0.1mm particles with a reasonable yield of 65% at 18% ash. INTRODUCTION Froth flotation has a long history of being used to treat coal fines. Coal flotation is considered to be difficult, if the percentage of Near Gravity Material (NGM), i.e. essentially locked particles, in flotation feed is >10% [Aplan, 1993], which is usually the case with all the coking coal fines in India. The fines are rich in vitrinite, so valuable for coking coal. Unfortunately, there appears to be no standard procedures to determine the separation efficiency of froth floatation. Release analysis proposed by C.C. Dell in 1953 [Dell, 1953], aimed to determine the ultimate floatability of coal. Several other techniques had been proposed but release analysis technique has been considered to be a vast improvement over the batch flotation process [Forrest et al. 1994]."

Jan 1, 2018

By Abhakumari

Effect of applied DC potentials on the bioleaching of a chalcopyrite concentrate in the presence of Acidithiobacillus ferrooxidans is discussed. Copper dissolution was the highest at an applied potential of +600mV (SCE), while all the dissolved copper got cathodically deposited at a negative potential of -600mV (SCE). Electrobioleaching at an applied potential of +600mV (SCE) was established at different pulp densities as a function of time. Effect of the magnitude of electrolytic currents on the activity and growth of bacterial cells was studied. Preadaptation of bacterial cells to the concentrate slurry and electrolytic growth conditions significantly enhanced copper dissolution. Electrochemical and biochemical mechanisms involved in electrobioleaching are illustrated with respect to oxidative dissolution and bio catalysis of anodic oxidation.

Sep 1, 2012

By Jacqueline Satur, Yoshiaki Kon, Buenaventurada Calabia, Xiao Sheng Yang, Arvo Naumanen, Kenzo Sanematsu, Sayaka Morita, Tetsuichi Takagi

Granite ores are composed of silicate minerals and a variety of valuable REE (rare earth elements)-bearing minerals, however the processing technique to recover these valuable minerals is not yet developed. In this study, the recovery of REE-bearing minerals by dry magnetic separation and wet high intensity magnetic separation (WHIMS)-settling from surface sample and from drill core sample, respectively, of a granitic REE-Zr-Nb ore deposit was investigated. The two samples have different mineralogy however in both samples, light REE are commonly contained in REE carbonate minerals while Y and heavy REE are commonly contained in zirconium silicate minerals and pyrochlore. The liberation size of the REE-bearing minerals in the two samples ranges from 10-250 ?m. Previous flotation testwork conducted on the drill core sample reported high recoveries of La2O3 (88%) and Ce2O3 (88%) but low recoveries of Y2O3 (42%), ZrO2 (17%), and Nb2O5 (29%). The objective of this study was to obtain higher recoveries of Y2O3, ZrO2, and Nb2O5 by dry magnetic separation and WHIMS-settling. Both processes implemented the application of a low magnetic intensity to initially separate the ferromagnetic minerals then a high magnetic intensity to recover the REE-bearing minerals. The results showed higher recoveries of Y2O3, ZrO2, and Nb2O5 by dry magnetic separation and WHIMS-settling indicating the potential of magnetic separation and gravity separation in recovering the heavy REE-bearing minerals. WHIMS-settling is more recommendable than dry magnetic separation because of its applicability in treating a wider range of particle size. In the WHIMS-settling, the light REE, Y, and Zr minerals were recovered mainly by applying four stages at high magnetic intensity of 21,500 gauss while the weakly magnetic pyrochlore was recovered mainly by decantation of the nonmagnetic slurry after a short settling time of 0.25 to 0.50 h. (MAX.300 words)

Jan 1, 2014

In recent years, coal beneficiation has gotten considerable attention. Selective oil agglomeration has been accepted as the best method to produce clean coal with a high removal of pyrite sulphur. In this study, spherical oil agglomeration of Datong coal fines was carried out using diesel oil as a bridging liquid. The oil agglomeration has a surface properties based on coal cleaning technique. The effects of fundamental parameters have been investigated including the concentration of bridging liquid, the size of coal particle, the solid content of slurry, the agitation time and rate, pH, surfactants on the agglomeration performance and various salts on the ash rejection and removal of pyrite of the agglomerated products. The optimum conditions of particle size, diesel concentration, solid content, agitation speed and time, pH and the dosage of active agent have been determined as less than 8µm, 20wt%, 1200r/min and 10 minutes, 7.5g/t and 100g/t, respectively. Under these conditions the ash content in the products can be achieved 1.5% below, the ash rejection was up to 92%. It has been observed that ionic strength of the aqueous medium affects the agglomeration performance. The precombustion coal cleaning process based on improved selective agglomeration results in high ash and pyrite sulphur removals. Over 80% removal of pyrite sulphur can be achieved from run-of-mine coals by offering a more cost-effective sulphur reduction solution rather than any other SO2 removal technology. In addition, the removal of pyrite sulphur is very necessary for not only the prevention of environmental pollution but also economical reasons.

Jan 1, 2014

By Chen Dong, Yang Wenwang, Liu Zhineng, Tan Ming

"To meet the requirement of production expanding of a certain potash ore dressing plant in Xinjiang province of China, industrial test of XCF/KYF-50 flotation machine was performed to process potash ore. The tank of XCF/KYF-50 flotation cell is in U shape, 50m3 of volume. This flotation cell is able to suck slurry by itself, and can be arranged on the same base level without high difference. In this paper, two sets of XCF/KYF-50 flotation cells were adopted to replace 8 sets of 8m3 flotation cell in original flow sheet of flotation. Aeration rate, slurry suction capacity, power consumption and slurry suspension are investigated. The measuring results show the slurry suction capacity of the flotation cell is larger than 12.80m3/min and solid particles disperse evenly in the tank without deposition. Industrial test result indicates that the final grade of concentrate is 26.69% at the recovery of 90.95%, which is up to expected performance. XCF/KYF-50 flotation cell has advantages of high flotation efficiency, significant energy saving and reasonable configuration of automatic control system, this kind of flotation cell can meet the requirement of production expanding of this potash ore dressing plant well."

Jan 1, 2014

By Z. Naziemiec

Since several years in Poland a huge demands on mineral aggregates occur, for the reason of intensive development of housing and road industry, as well as industrial building. Limitations in re-sources of broken aggregates in Central and Northern parts of Poland cause, that both the non-waste production of aggregates with high quality and the production of alternative aggregates from recycling gain greater importance, nowadays. It entails increase in demands for crushing devices, which are easy and reliable in operating as well as inexpensive and enabling to obtain a good quality products. Jaw crusher, regarded as the most spread in Polish industry, meet these requirements, however, their crucial disadvantage is a large content of irregular grains in crushing products. Numerous investigations show, that the shape of grains is a significant feature of aggregates, which influences on durability and quality of produced concretes. The advantage of jaw crushers is their easy operation, low price as well as low amount of dusts (wastes) generated in comminution products in comparison to other types of crushers (i.e. hammer crushers).

Jan 1, 2014

By R. Kobialka

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

Jan 1, 2014

By A. Vilinska

Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral-solution interface. Recent developments in biotechnology have not only aided hydrometallurgical leaching operations but also shown great promise in mineral beneficiation processes. The adhesion of bacteria on minerals alters the surface properties relevant to flotation and flocculation of minerals. The biomodification of mineral surfaces occurs through the attachment of microbial cells, oxidation reactions and adsorption or chemical reaction with the metabolite products. Several types of heterotrophic and chemolithotrophic bacteria have been successfully applied in flotation and flocculation processes for the last two decades. Al-though the potential of microorganisms in minerals beneficiation has been realised by several re-searchers from their laboratory investigations, the studies were mostly confined to pure mineral systems and there is hardly any sincere effort to apply the methodologies on ores. This paper presents a brief summary of the literature in bioflotation and bioflocculation, and attempts to outline new dimensions of research for a practicable application of this technology in mineral industry.

Jan 1, 2014

By G. Prabhulingaiah, D. M. R. Sekhar

"A phosphate deposit of estimated 6 billion tons of P2O5 is located 180 to 300 meters below the sea level, 185 kilometers north of port Luderitz, Namibia. The ore bed is 6 kilometers wide and 220 kilometers long. The ore deposit analyzing 16% P2O5 is loose sediment of 1.5 meters thick without over burden. Sizing of the ore to - 1.4 mm + 0.150 mm improves the grade to 23.54% P2O5 with a P2O5 recovery at 83.75% containing phosphate pellets and flakes of sea shells. Clay, bacterial debris as organic matter, flakes of broken sea shells and fine phosphate containing particles report to - 0.150 mm fraction and + 1.4 mm fraction contains sea shells and few phosphate containing pellets. The mineralogical composition of phosphate containing pellets is estimated (Droste, T.C., 2004) 80% frankolite, 6% pyrite, 4% illite, 3% quartz, 3% amorphous SiO2, 1% carbonates, 1% organic carbon and = 1% ilmenite, magnetite, zircon etc. The phosphate content in the pellets is around 27.7% P2O5. Trials to separate by gravity or flotation processes were not successful. Leaching of carbonates (sea shell flakes) under mild acidic condition (= 2% acetic acid or HCl solutions) or calcinations followed by leaching however yielded residues (concentrates) of grades 27.85 - 32.74% P2O5 at P2O5 recoveries ranging from 78.45 - 96.8% P2O5."

Jan 1, 2014

By Ricardo Montero

At this time, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc. After the use-phase, the electronic devices become electronic waste (e-waste); consequently it is important to consider e-waste as a secondary supply for recovery of these metals. One of the most important components is the printed circuit boards (PCBs) because the amount of their precious metals is ten times higher than rich precious metals bearing ore. This paper presents the recovery of Au, Ag, Cu and Nb from PCBs of discarded computers using leaching column technique. The amount of these metals in used PCBs was: 613 g/ton of Au, 1515 g/ton of Ag, 36 g/ton of Nb and 23.4 % of Cu. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm. Then, it was leached with sodium cyanide solution in a glass column using the following conditions: sodium cyanide concentration 4 g/L, flux 20 L/kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained: 46.6% of Au, 51.3% of Ag, 47.2% of Nb and 62.3 % of Cu. The products obtained are: a) loaded carbon that contains the desired metals and b) processed PCBs with precious metal contents. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of US$ 155 639, considering the recovered metals from loaded carbon. The internal rate of return for 10 years period (IRR) and net present value (NPV) estimated are 27% and US$ 105 926 respectively. Keywords: printed circuit boards, recovery, precious metals, niobium, leaching column

Sep 1, 2012

By Tom Liu

This paper is a fundamental study of bubble-particle collision efficiency in turbulent flows. A CFD-based microscale scheme for the prediction of turbulent bubble-particle collision efficiency in a 3D isotropic turbulent flow is developed, and in this way, turbulence effects on particle-bubble collision efficiency are taken into account for the first time. By comparing the computed results with experimental data from the literature, the CFD simulation is shown to correctly predict the bubble-particle collision efficiency in a quiescent environment. The CFD method was then applied to the investigation of bubble-particle collision efficiency in a turbulent flow, and the simulation results are shown to be qualitatively consistent with the real observations. The predicted collision efficiency can be used in a multiscale modelling scheme, which would account for all control variables in a flotation cell, such as impeller structure and tip speed, air nozzle structure and air flow rate This study indicates how microscale simulations of bubble and particle behaviours, coupled to macroscale CFD simulations of flotation cells, can provide a powerful tool predicting the flotation rate in a real flotation cell.

Jan 1, 2014

By H. R. Manouchehri

The importance of the grinding environment and its effect on sulphide minerals flotation behavior has been known for many years. The grinding environment may play a role in controlling fine and coarse particle flotation along with dissociation of different chemical species in grinding environment. Dissociation of different chemical species and ions within the process water may result from changing the grinding environment. The mining and mineral processing industry undertakes activities that may impact on water resources. These include use and storage of chemical storm-water management, process water management, mine dewatering and management of tailings. In mineral flotation understanding and controlling water quality is paramount important not only because of its effect on flotation but also with respect to control the quality of the water which is released to the environment. Releasing of different anionic and/or cationic chemical species in the process water results from the interactions among different mineral within the ore, process water, and the milling environment. In fact grinding mill acts as an electrochemical reactor which affects the flotation performances of different value minerals as well as the quality of the tailing products. An increasing in antimony content in process/discharge water at Boliden?s Tara processing plant in Ireland to above limitation level was reported in April 2010 which needed to be controlled. An increase up to 6 times of the permitted level was reported which needed an immediate action to control due to environmental considerations. Therefore attempts were made to detect why this higher amount of Sb is released and how to control and minimize its release to the process/reclaim water. This paper discusses how/why Sb content in process/reclaim water was increased by changing the mill electrochemistry and the strategies were taken into considerations to control it. Different strategies, including electrochemical controlling of the milling section, Fenton process, using Bauxsol in treating the process water, etc., have been considered and tested which are described herein. All strategies taken into consideration for solving the problem were successful which indicated good understanding of the issue and good decision making. Furthermore, for each solution the capital and operational costs were roughly estimated. Accordingly, the Sb content in process/discharge water was controlled to a value lower than allowed limitation, i.e., 1 ppm. Keywords: antimony, water contamination, mill electrochemistry, ag milling, grinding media, eh-ph, sulfide minerals, fenton process, bauxsol, lime addition

Sep 1, 2012

By F. M. Zafar Kaifi

Magnesite producing companies rely on high grade purity MgO. The mineralogy of magnesite has a significant impact on the manufacturing of magnesite bricks. The manufacturing process of bricks companies utilizes 90% magnesite from 85%~90% MgO. The main objective of the magnesite bricks was to utilizes the indigenous raw material available in bulk quantity. With better under-standing of chemistry of the mineral species and strict control of bricks manufacturing/processing conditions can be better produce efficiently, a low cost high quality bricks with minimum detrimental environmental impact.

Jan 1, 2014