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By R. X. Li

The overall flow-sheet of producing chromium (III) sulfate is described in this paper. The suitable conditions of each process such as sintering, leaching, aluminum removal, reduction, and de-composition conditions were experimentally studied. The results show it is reasonable to produce chromium (III) sulfate with the flow-sheet pointed out in this research work. The final product is Cr2(SO4)3 solution contained 150~250g/L Cr.

Jan 1, 2014

By G. Venkateswara Rao

The multi-gravity separator (MGS) is a novel piece of equipment for the separation of fine and ultra-fine minerals. However, the published literature does not demonstrate its use in the separation of Iron ore fines. Therefore, an attempt was made to study the effects of different process variables on the performance of an MGS for the beneficiation of Iron ore fines. The results obtained from this study revealed that among the parameters studied, drum rotation, amount of wash water and angle of inclination play dominating roles in controlling the yield and grade of the Iron ore. The majority of the newly developed Multi gravity concentrators have tremendous potentials for various applications. Therefore, the performance evaluation of these concentrators treating various minerals, coals, heavy metal recovery from tailing dams, etc., have become an active research topic. Several attempts have also been made to develop appropriate mathematical models of individual concentrators. Despite all these efforts, these concentrators have yet to find the widespread applications they deserve. The ?as received? sample assayed 40.80% Fe, 40.90% SiO2,0.24% Al2O3and 0.20 % LOI and all other trace elements within the specified range. The current paper deals with the Mineralogical studies, characterization and process amenability studies of Sub grade Iron ore from Deposit No. 5, Bacheli complex of Bailadila using Multi Gravity Separator (MGS).

Sep 1, 2012

Much has been published in recent years on the challenges facing the engineer of the 21st century and the consequent challenges facing the education providers and industry. The world is changing rapidly on the social, economic, political, technical and environmental fronts and our metallurgists/mineral processing engineers of the future will arguably need to have a different set of skills than those which were traditionally regarded as adequate during the latter half of the 20th century. This paper attempts to explore some of these issues and their ramifications.

Jan 1, 2014

By S. S. Lu

In sodium oleate and salicylhydroxamic acid systems, sequence of floatability of three sulfate minerals is: barite>celestite>gypsum, in lauryl amine system is: gypsum>celestite>barite. XPS and infrared spectrum analysis are used to find that it is chemical reaction between sodium oleate and three minerals, physical adsorption on the surface of minerals for lauryl amine, and it is chelating reaction between salicylhydroxamic acid and three minerals possibly. Theoretical calculation on chemical bonds in crystal structures of three minerals is carried out, finding that breaking degree of Mn+?O2- in crystal structures of three sulfate minerals is closed related with floatability.

Jan 1, 2014

By V. Panayotov

Slag and by-products of metallurgy bear valuable components and their processing raises an in-creasing interest. Coke and iron have to be separated and other components have to be depressed, in order to obtain sellable high quality copper concentrates. Use of classical mineral processing technologies, such as magnetic separation, sulphidization, hydrometallurgy, etc. yields copper concentrates with grade of 4%~6% Cu. Copper is lost in tailings and the whole technological cycle is low profitable. Technology proposed applies an electrochemical treatment of the industrial water entering the flotation cycle. Iron and iron compounds that do not bear Cu, coke and gangue materials are depressed during the copper flotation. Copper concentrate of grade of 9.8%~10% Cu is obtained at simultaneous increase of Ag recovery by 8%~10%. As a result company profitableness is increased. Technology proposed is easy to implement, it does not require changes in the existing technology flow-sheet, and additional investment is low. The flotation process can be aided by a specially developed system for real-time analysis of the obtained copper concentrate which allows in-time corrections in the flotation parameters and entire process control. Applied flotation schemes, technological parameters and results obtained are described.

Jan 1, 2014

By Hao Zhang, Dezhou Wei, Qiang Zhao, Caie Zhang, Baoyu Cui, Xuetao Wang

"Nowadays, long periods of relatively low iron ore prices have made the steel industry get the greater pressure. To develop appropriate processing technology based on characteristics of the iron ore, so as to reduce the beneficiation costs, is crucial to the improvement of iron and steel enterprise competition. For a typical low-grade iron ore from northeast China, beneficiation process research was conducted based on the in-depth studies of ore characteristics. Results show that the iron grade of the ore was 31.56%, the content of FeO was 6.59%, the main iron minerals were hematite and magnetite with fine dissemination sizes and partly scattering in gangue; With the grinding fineness of 65% passing 0.074mm, and regrinding fineness of 90% passing 0.074mm, the concentrate with 66.80% iron and recovery of 82.90% was obtained via the combined flowsheet of stage grinding – classification – gravity concentration – low and high intensity magnetic separation – reverse flotation. Ratios of gravity concentration and low intensity magnetic separation were 70.21% and 7.57% respectively in 40.42% of total concentrate yield; The loss of micro-size fractions can be reduced by feeding spiral tailings into magnetic separation and flotation; It’s helpful in reducing the dosage of reagents and beneficiation costs by increasing the throughput of gravity concentration and outputting concentrate of low intensity magnetic separation.INTRODUCTION Iron and steel industries are facing the increasing pressures in the continued falling iron ore prices. In order to improve the competitiveness, it is extremely urgent for them to develop more appropriate separation process for the reduction in iron ore beneficiation cost. As a typical low-grade iron ore, Anshan-type iron ore is one of the most important iron ore resources in China [1-3]. The flowsheet of stage grinding and separation contained the classification of the coarse particles and the fine particles, the gravity concentration, the magnetic separation and the anionic reverse flotation has been widely applied for Anshan-type iron ore. With the appropriate separation progress as well as equipment, satisfactory separation results had been obtained, and mineral particles with different size were recovered separately [4-7]. However, the low recovery of fine mineral particles and the relatively high beneficiation costs still prevented the efficient application of the process [8]. For a Anshan-type low-grade iron ore, a typical process flowsheet, as mentioned earlier, with stage grading, classification of the coarse particles and the fine particles, gravity concentration, magnetic separation, anionic reverse flotation was adopted currently. And the concentrate with 67.10% iron and recovery of 75.50% was obtained and the gravity concentrate accounted for 39% of the total concentrate. However, a large amount of fine liberated iron ore particles were lost in the tailings."

Jan 1, 2018

By Z. M. Dai

Microorganisms in AMD (Acid Mine Drainage) were enriched in 9K culture medium. The enrichment was applied to leach copper pyrite after the microbial community structure and metabolism was stable. Before and after bioleaching, the microbial DNA was extracted and applied to RFLP (restricted fragment length polymorphism) analysis to demonstrate the relationship between the leaching efficiency and the change of microbial community. Atomic absorption spectrometry results showed that when concentration of the pulp was 10% and pH were 1.5, 2.0 and 2.5, the leaching rate were 56%, 57% and 34% on the 18th day respectively. These results indicated that the rise of pH resulted in the decrease of leaching rate. In lower pH condition, the growth of microbe was faster: when pH was 1.5, the microbial cell number reached to 1.4×107cells/mL on the 9th day; while pH was 2.5, the microbial cell number decreased to 4×106cells/mL. The analysis of microbial community structure showed that Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans were dominant species before bioleaching (account for 43% and 32% respectively). And after bioleaching, these two species were still dominant when the initial bioleaching pH were1.5 and 2.0. While the initial bioleaching pH was 2.5, the proportion of these two species decreased. These results demonstrated that the initial bioleaching pH would affect the microbial community structure in bioleaching system at room temperature, and this affect could lead to different copper pyrites bioleaching efficiency.

Jan 1, 2014

By M. Paymardi, A. Foroutan, T. P. Oladele, M. Abbaszadeh

"Reducing the amount of zinc and iron in lead concentrate is one of the important aspects of processing in lead and zinc flotation plants which results in improvement of lead concentrate quality and prevents zinc loss. In mineral flotation industries, lignin sulfonates are known for their depressant properties for both non-metallic and sulfide minerals such as pyrite and pyrrhotite.This paper investigates the effect of lignin sulfonate on flotation of galena, sphalerite and pyrite in sulfidic lead and zinc bearing ores. Batch flotation tests were carried out on a high pre-activated zinc samples. The feed contains 0.9% lead, 2.3% zinc and 7.5% iron. The dosage of all reagents such as sodium cyanide, zinc sulfate, ethyl xanthate and methyl isobutyl carbinol (MIBC) were kept constant for lead flotation step except calcium lignin sulfonate (CLS) that was varied between 0 and 80 gr/ton.Results for lead rougher concentrate showed that the grade of lead increased by 2.7% while the recovery decreased around 4 % at the highest dosage of CLS. Furthermore, zinc recovery decreased by 6.3% with no significant change in grade. Iron recovery in lead rougher concentrate decreased by 2.3 % while the grade changed around 1%. In sphalerite flotation step, CLS dosage was changed in the range of 0 to 80 gr/ton while the dosage of other reagents such as copper sulfate, lime, amil xanthate and MIBC were kept constant. In this step, no decreasing in grade and recovery of zinc was observed, while iron recovery decreased. It was suggested that CLS has a depression effect on sphalerite in conjunction with other zinc depressants such as zinc sulfate and sodium cyanide. CLS was further used in plant with non-pre-activated zinc minerals. Similar trends were observed in plant.INTRODUCTIONlead-zinc sulfide minerals play an important role in the production of lead and zinc metals in the mineral processing industry (Luo, Feng et al. 2016). Due to complexity of the lead-zinc ores mineralogy, in some situations, their flotation properties vary significantly from one deposit to another one even in itself (Bulatovic 2007)."

Jan 1, 2018

By Z. G. Li

The large-scale vibrating screen has been applied widely in coal industry and other industrial areas as a kind of important device. As vibration mechanical device, it works very hardly and works in very bad environment so that the structure of screen is damaged easily. Therefore, it is very important that how to detect the fault of structure as early as possible to make the repair schedule reasonably and economically and to avoid the body hurt and device damage. As a kind of important structure of vibrating screen, the lower crossbeam is the main carrying structure and it is easily damaged, so it is regarded as a researched object in this thesis and it is tested under the load in the laboratory. Based on the test, acoustic emission wave signals can be got-ten by modern acoustic emission testing technique. Then, the ?wavelet packet - energy? from the characteristics of acquiring signals is used as neural network input vector. In the BP network structure design, the design of a hidden layer with variable number of BP network is established. Based on the error by contrast, the best nerve number can be identified in the hidden layer. Through integrated analysis, using Levenberg-Marquard BP study algorithm, network-training errors are relatively small, the acoustic emission signal is used in BP neural network as a pattern of recognition. In Matlab6.5, neural network model identification is created and taking advantage of nonlinearity and the ability of learning and memory of Neural Network, this model is fixed by training structure of network with training samples. The work presented shows that acoustical emission signal processing and research on early fatigue fault diagnosis based on the wavelet and the neural network is viable.

Jan 1, 2014

By H. M. Gao

According to the difficulty of dolomite removal from collophanite,normal-reverse floatation process has been adopted in floatation with the use of highly selective collector G-4 and depressant S721. Good indexes of flotation have been obtained with the run-of-mine ore containing 17.96 % P2O5 and 2.31 % MgO being upgraded to a concentrate containing more than 30% P2O5 and less than 1% MgO. The reagent interaction mechanism in low grade collophanite flotation has been stu-died by FTIR analysis and theoretical calculation. The results indicate that the interaction between collector G-4 and collophanite is the result of chemical adsorption in combination with physical ad-sorption with chemical adsorption playing the major role. Depressant S721 adsorbs on dolomite surface to form a water film and effectively depresses the flotation of dolomite and reduces the MgO content in the concentrate.

Jan 1, 2014

By N. Karapinar

Ferrihydrite, a member of iron oxides family, has been used as an adsorbent for the removal of heavy metal ions from industrial wastewater. The success of the operation depends mainly on the efficient removal of ferrihydrite from the aqueous phase. Hence, the emphasis of this study was given on the separation of ferrihydrite by high gradient magnetic separation (HGMS) method to overcome solid-liquid separation difficulties of ferrihydrite. Magnetic seeding technique in which the magnetite mineral was chosen as a seeding reagent was used to make magnetic separation available. The method clearly involves the attachment of ferrihydrite to a magnetic seed material and subsequent magnetic separation of ferrihydrite ? magnetite coagulates. Seeding of ferrihydrite with magnetic particles was achieved by exceeding the solubility limit of the ions in the presence of dispersed magnetite. Magnetic separation results of seeded ferrihydrite showed that maximum seeding performance is obtained in the pH range of 7.0~10.0. Iron/magnetite ratio had a marked effect on the separation of seeded iron oxide precipitate by HGMS. This ratio determines the operation parameters such as magnetic field strength and flow rate. It was concluded that when used with magnetic seeding technique, HGMS can be used to surpass separation difficulties of ferrihydrite used in adsorption-based treatment techniques.

Jan 1, 2014

By M. Guo

Coal-based Direct Reduction in Interior-combustion Shaft Kiln (CDR/ISK) is a brand-new technique. Compared with the traditional Coal-based Direct Reduction (CDR) technique, its main character is to use Interior-combustion Shaft Kiln (ISK) as the reactor of direct reduction. After being crushed and grinded, iron ore is made into green pellet, which will be surface-coated by coal fines. Then, the surface-coated green pellet can be directly reduced in ISK. The pellet should not be too dry and should be charged from the top of ISK. Oxygen-contained air should be blasted into ISK to keep the temperature in it higher than 1000 degrees centigrade, at which iron oxide will start direct reduction. The reduced pellet will be discharged from the bottom of ISK and after de-surface-coated, spherical Direct Reduced Iron (DRI) can be gained. The volume of carbon monoxide in the off-gas discharged from ISK is less than one per cent. By using this technique to get one tonne DRI, the consumption of coal is about 300kg of fixed carbon, which is much lower than the energy consumption by using other CDR techniques. There is a lot of complex refractory iron ore in China, which remains unexploited. The iron-bearing minerals in this kind of the iron ore can not be beneficiated economically by present technique of gravity, magnetic, flotation or magnetic roasting because the iron minerals are too very finely disseminated to be liberated, or, the iron minerals are too similar to gangue to be separated each other. By using CDR/ISK, complex refractory iron ore can be directly reduced in lower temperature and all kinds of iron mineral can be turned into iron metal. As the grains of iron metal growing larger during direct reduction, magnetic separation can be used to separate iron metal from gangue mineral, thus high-grade iron metal fines can be gained. According to the experiments, the grade of iron metal fines is above 90 percent and the recovery of iron is higher than 90 percent. The consumption of coal to process one tonne of complex refractory iron ore is only about 90kg of fixed carbon.

Jan 1, 2014

By Sergey Romanenko, Tatyana Aleksandrova, Karen Arustamian

"Current status of question about grinding stage effect to electrochemistry parameters of operation preparation slurry before intermediate selective flotation was assessed in the present scientific work. Needs of more detail study chemical reactions in the slurry preparation and flotation processes were shown. The ores are polymetallic sulphide type and the one are most difficult for mineral processing. The methodology allows increase information base during floatation tests. Ionometric methods and elements of neural network have been used in the study of mineral processing questions.We have also identified the relationship between the received values of the electrochemical parameters and the technological results in selective flotation. The optimal values of the electrochemistry parameters in operation of the preparation slurry before selective flotation has been found. The main effect of using the proposed methodology is to obtain scientifically based solutions to improve the technology parameters of flotation polymetallic sulfide ores. Challenging issue of selectivity of sulphide-polymetallic ores will be considered using case study of sulphidepolymetallic ores. It was shown that several factors are formed in ore grinding: formation of hydroxyl oxides of iron compounds, copper cation leaching, metal-sulphide and metal-sulphite complexes formation. The chemistry was revealed for current processes in slurry preparation operation before selective flotation. Quantitative assessment of interrelations between electrochemical parameters of slurry and process performance was given with using electrochemical control methods. Neuron network-based model was estimated based on data array and was allowed to establish optimum electrochemical conditions of metal-sulphite complex formation to provide maximum efficiency of selective flotation.INTRODUCTIONPhysical and chemical processes that take place in ore grinding have a significant impact on flotation selectivity and can cause low selectivity of the flotation process. Today this issue is given much attention. In the paper [1] it is pointed out that sulphide oxidation products and slurry components, such as sulphide ions, metallic iron and its oxidation products, have effect on flotation performance. So, metallic iron has impact on metal-sulphite complex formation as a result of oxidation-reduction reactions as follows:"

Jan 1, 2018

This paper discusses current workforce demand projections for mineral processing engineers and emerging trends in mineral processing education. Attempts are made to identify gaps that often result in a mismatch between skills taught and skills needed by the practicing engineer. Clear examples of this include a less than uniform training in chemical aspects of mineral processing, and an understanding of the statistical and experimental design tools necessary to tame the often-large variation in operational parameters and plant data. The end goal is an educational system modernized to prepare mineral processing specialists for productive careers in the sustainable development of natural resources. A framework for revamping education based on an integrated modular approach is also presented. Keywords: mineral education trends, mineral processing programs

Sep 1, 2012

By L. A. Vaisberg

"Mining processing plants are the most high-performing industrial enterprises in the world economy system. Even at an average-scale mining enterprise, the grain-size separation equipment continuously processes 105 to 106 dissimilar mineral particles per hour. In separation by physical properties, their number increases by at least 10 to 50 times. Mathematical modeling of such a high flow of discrete particles is carried out using two different approaches: the discrete-particle and the phenomenological methods. The calculations demonstrate the possibility of handling big data when describing the processes of separation of granular material. INTRODUCTION The interest to the screening process and the process of formation of new screen designs in Mekhanobr is traditional since the moment of its foundation. It is symbolical that the first publication of the Mekhanobr proceedings in 1924 was the monograph dedicated to screens and screening products as such, which was the first one in the world at that moment. It was a book of Prof. L. B. Levenson, one of the founders of Mekhanobr, who headed the Technical Bureau of the Institute. Vibratory screening is the most mass process in the technologies of solid minerals processing, which determines significantly the energy demands of crushing and grinding cycles, and at some enterprises determines the quality of the final product, for example in case of crushed stone, coal or abrasive materials production. The general understanding and simulation of the process of poly-dispersed granular materials vibratory screening was developed at several conceptual levels taking into account the features of classification of materials with different size and density.Considering the real industrial processes of vibration screening, it shall be noted that at the sieve surface of the screen in the initial part of the deck the classification in a thick material layer (in natural conditions) occurs, which further transfers to a thin layer (free movement). In the process of screening of light minerals, for example coal or metallurgic feedstock, screening is mainly performed in the thick layer."

Jan 1, 2018

By Diogo R. Prado, José Aurélio M. da Luz

Drying operation can have a major importance in a mineral processing undertaking. The proper sizing of dryers can ensure the specified dewatering level without energy wastage. However, often the sizing of fluidized bed is done disregarding the actual residence time distribution (RTD) of the particles inside the reactor. In this case it is usual to adopt the average residence time as a design criterion. In this work, we have quantified the effect of residence time distribution on drying, ensuring that a previously adopted fraction of the particles remains inside the reactor for the required time lapse needed for drying. Design criteria such as particulate flow rate and drying time, taking into account the statistical distribution of residence time was studied, matching the thermodynamic and fluid dynamic aspects of the drying process. Experimental tests carried out have confirmed the RTD for a teetering bed as the same for a canonical ideal mixing system. Although the fluidized bed volume using the proposed formulation was higher than that found for the average time based procedure, the efficiency gain in drying has proven advantageous.

Jan 1, 2014

By M. Nonaka

An attempt to produce fuel from biomass waste by hydrothermal treatment has been made with expectation to effectively utilize a renewable source of energy and an unexploited energy resource. In this paper, we have used empty fruit bunch (EFB) that is a residue after recovery of crude palm oil from palm oil trees in a plantation in a tropic country. A hydrothermal treatment was conducted using a 500 mL autoclave, with alkali (K2CO3) catalyst. EFB was decomposed more by alkali catalyst of lower alkali content and rather polymerized in higher catalytic region. The functional group composition of the solid phase oil is similar independent of alkali content, however its burning characteristic became more incombustible with increasing alkali content.

Jan 1, 2014

By V. A. Vorob'ev, A. N. Larionov, E. N. Ivanov, M. A. Ryazanov

The aim of the research is to increase the recoverable value of poor, difficult-to-digest complex mineral raw materials. In the Republic Belarus, universal centrifugal-shock devices have been created for crushing, grinding and classification of ore and non-metallic mineral raw materials in dry mode, which differ from foreign analogues by a higher level of resource saving (including electricity and materials). Dry-ore preparation technologies have been tested on a pilot scale: fine crushing (replacing grinding in rod mills), grinding (replacing wet grinding in ball mills) and pneumoclassification on different types of ores, - which made it possible to identify the criteria for the suitability and unsuitability of mineral raw materials for their use. The possibility of regulating the upper and lower limit of the size of the finished material is established, the possibility of reducing the yield of slimes (-0,020 mm) to 5 times is determined. A comparative analysis of the contrast degree of separation characteristics of ore a similar granulometric composition, crushed in wet and dry conditions, is performed. The achieved contrast degree of gravity properties after dry grinding - 104,3; after the wet - 60.2. When enriching on a centrifugal concentrator, gold recovery to the concentrate after dry grinding increased by 13.12% while improving the quality of the concentrate from 78.3 g/t gold to 90.75 g/t. When testing the gravity-flotation scheme for the enrichment of poor gold-quartz ore, the increment of gold extraction after dry grinding was 7.6% for gravity and 9.5% for flotation; the total increase in extraction is 17.1%. The possibility of flotation of a larger material after dry grinding has been proved, with an extraction gain of 1.5% compared to the flotation of thinner material after ball milling. The influence of dry technology on the efficiency of the leaching of gold and silver (an extraction gain of 5.5 to 10%) and heap leaching (extraction gain - up to 18.3%) was studied. The positive influence of dry ore preparation technologies on the efficiency of gold and silver heap leaching and heap leaching, thickening and filtration is proved. Lines of dry ore preparation technologies can be used in modular complexes for processing technogenic raw materials.

Jan 1, 2018

By J. Roth

The increasing demand of the filler industry regarding fineness and better delaminated products led to the development of a series of different grinding machines, which differentiate basically by the grinding mechanism as well as the kind of classification. Spiral jetmills grind, as it is well known preferably by delamination, therefore a spiral jetmill with integrated dynamic classifier has been developed. Especially the enhancement of the functional properties of the used industrial mineral fillers is a factor of highly increasing importance. These properties are very often bound to the platy shape of the minerals expressed by the aspect ratio. The developed Spiral Jetmill shows sufficient ability for such delamination and therefore increases in aspect ratio. In a series of comparative tests the suitability and advantages of this system regarding achievable fineness down to the submicron range as well as the conservation or even improvement of the aspect ratio of different minerals has been studied. As an emphasis on the results application tests with certain materials in the plastics field have been conducted. Due to the fact that in this range the required specific energy for achieving the necessary fineness increases exponentially another target is to optimize the grinding efficiency. A special feed control system provides on one hand a sufficient load inside the mill to obtain maximum utilization of the applied energy and on the other hand to prevent the mill from overfilling and coming with this a poor classification. The integrated classifier is a combination of a high speed motor with directly attached classifier wheels. This unit on one hand grants the necessary high circumferential speed of up to 190 m/s for providing an exact top cut of the ultrafine products and on the other hand gives the required operational reliability for continuous operation. Hard grindable impurities, which enrich inside the mill chamber, can be rejected from the process leading to an even cleaner product. Comparative tests on a talc product with certain free quartz impurities showed a significant improvement of the final product with respectively low loss on rejected material. This effect again had a beneficiary impact on the suitability of the final product when used in plastics application.

Jan 1, 2014

By Ana Elisa Casas Botero

The Rhodococcus opacus microorganism was evaluated as a biocollector for flotation of barite. The electrophoretic behaviour of the mineral, before and after R. opacus interaction, was evaluated and showed that the cells adhesion shifted the mineral zeta potential curves. Adhesion tests were suggested a high affinity of the bacteria for barite. The experiments of the adsorption rate of the R. opacus on the mineral surface showed fast kinetics, achieving a maxim of cell adsorption after 5 minutes. Adsorption isotherm curves for barite could be categorized as Langmurian (L) type II. The best bioflotability results for barite achieved values around 75% for a R. opacus concentration of a R. opacus concentration of 250 ppm in the pH around 5.0. The studies were compared with the flotation of barite using a traditional collector. The bioflotation experiments were discussed considering the obtained adhesion tests. The results were supported by the Thermodynamic approach for selected pH values. The fundamental flotation studies showed the paramount potential that R. opacus presents as a biocollector and its possible application in the mineral flotation industry.

Jan 1, 2014