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By Ruiyang Zhang, Ping Fang, Dezhou Wei, Shuling Gao

A CFD based numerical simulation of flow characteristics of hydrocyclone was conducted with different structural and operational parameters to investigate its distribution characteristics and influencing mechanism. The results show there exist several unsymmetrical envelopes of equal vertical velocities among both upward inner flows and downward outer flows in the hydrocyclone, and cone angle and apex diameter have remarkable influence on the vertical location of the cone bottom of the envelop of zero vertical velocity. It is also found that some tangential velocity isolines exist in the horizontal planes located in the effective separation region of hydrocyclone, and feed pressure has almost no effect on the distribution characteristics of both vertical velocity and tangential velocity of flow in hydrocyclone, however the magnitude and gradient of tangential velocity are made increased obviously, so as to make the high density particles motion velocity to the wall increased and to make the cyclonic separation effect improved. The simulation results also show when the apex diameter increased, the pressure of the fluid field decreased, however the pressure grads in the apex district increased, and the degree of changing is different as the cone angle, which showed some interactive influence of cone angle and apex diameter on the fluid field of hydrocyclone. While the feed pressure also has almost no effect on the pressure distribution characteristics, however the its magnitude and gradient are made increased accordingly, which can improve the separation accuracy according to particle density.

Jan 1, 2014

By C. Perez

In mineral processing plants it is important to estimate rock composition, size and grindability to improve control of the grinding process. It is well known that variation in ore grindability and size distribution directly affects mills power consumption and throughput. This paper extends a general machine vision approach for on-line estimation of rock mixture composition using color information. Our proposed rock lithological recognition method requires the following steps: division of each image into sub-images, color feature extraction using the Binary Quaternion-Moment-Preserving thresholding technique (BQMP) and support vector machines (SVM) for classification. The BQMP thresholding technique splits the image in two and chooses representatives of each half using the histogram as features. The statistical parameters of the color data can be expressed using the quaternion moments into the representatives. This method can be recursively applied to the sub-images, obtaining 5x2n features in n iterations. Once the feature vector has been computed, each vector is assigned to one of three classes using a classifier. The method was tested on a database containing 20480 sub-images (64x43 pixels) of five ore types as follows: massive sulphide (MS), disseminated sulphide (DS), net textured (NT), gabbro (G), and peridotite (P). These ore types were assigned to three grindability classes: soft (MS), medium (DS and NT) and hard (G and P). The database was divided in 2 subsets: 15360 sub-images used for training and cross validation and 5120 sub-images used for test. The classification accuracy was compared with a method previously published based on a mixture of principal components analysis (PCA) for color, and wavelet texture analysis (WTA) for texture feature extraction. WTA-PCA approach reached a 76% accuracy in test while our BQMP method reached 90% of classification accuracy using only color features. Experimental results show that our proposed method yields excellent results compared to previously published results. Keywords: rock classification, lithological classification, grindability estimation

Sep 1, 2012

By F. Karakas

Water based paint formulations consist of some industrial minerals with quantities varying from 20 to 50 %. Quality of paint is directly related to these minerals used as pigment or filler in the production. Titanium dioxide is the most important and expensive pigment in paint formulations. Other minerals such as calcite and calcined kaolin are used as filler and mainly as a substitute for TiO2. Consequently, particle-particle interactions including adsorption, coating and size distribution of pigment mixture directly affects the paint quality. In the present paper, a new type of pigment mixture for possible use in architectural water based paints was developed through grinding. The effect of different types of grinding methods on physical properties of TiO2 and calcite mixture and the quality of paint produced by these mixtures have been revealed. Three different types of mills; conventional ball mill, vibratory ball mill and high-speed attritor were used for grinding of TiO2 and calcite. Viscosity, zeta potential and particle size distributions were used to characterize the pigment mixtures obtained upon grinding. The quality of paint was evaluated by standards based on both wet and dry paints such as viscosity, density, opacity and gloss. The paint produced with the pigment mixtures prepared in vibratory ball mill and high speed attritor showed improvement in physical properties particularly in the distribution and dispersion of mineral particles. Keywords: grinding, pigment, paint, TiO2, calcite

Sep 1, 2012

By Anatoly Usov

The detailed researches of a broad circle of problems connected to development of the electric pulse method destruction materials (EPD) of a various nature and area of use are executed. The electrical and power characteristics of process, physical fundamentals of selectivity of a breakdown and destruction are investigated, the device of electric pulse (EP) disaggregation and ?omminution of materials are developed, the technological efficiency of disintegration of industrial minerals estimated. Due to its technological advantages, the EPD could have a great potential in minerals mining and processing technologies. Low specific power and weight-and-size characteristics of EP installations based on the existing out-of-date electric equipment are at present the main reasons hindering the effective application of the method in mining and processing technologies. The main studies carried out in Russia in the field of electro technical equipment development for EP technology are presented. The pulse capacitors service life affects greatly the economic efficiency of the process because the capacitors cost accounts for a considerable, and in some cases, the most part of the operational costs. Determined and analyzed in the study are the ways which could significantly improve the specific characteristics of high voltage pulse generators (VPG), such as to use of high-frequency voltage transformation to develop a charger; to use pulse transformers (PT) with iron magnetic circuits made of materials characterized by high magnetic permeability, in pulse generating circuits; as well as to use special ways which could produce voltage pulses with a short front. The experiments have proved the possibility to adapt these technological solutions for EP devices, and a further strategy of the EP technologies development and application has been suggested on this base. Keywords: electric pulse disaggregation, electric pulse installation, charger battery, high voltage pulse generator

Sep 1, 2012

By U. M. J. Boin, W. L. Dalmijn, T. P. R. de Jong

"This paper explores the complex interrelationship between the resource cycle, recycling and metal production as a function of economics, environmental legislation, and product design. It is argued that central to optimising this resource cycle lies the control in particular of physical separation plants by the application of advanced sensor technology and sorting equipment, as well as suitable control and sampling algorithms supported by optimising mass balance models.Metals are produced through a long chain of processes. For primary resources, metals production goes through mining, mineral processing, ore smelting, conversion and refining steps or via low temperature hydrometallurgical processes, or a combination of both pyro- and hydrometallurgical operations. For the recycling of resources, metals are separated and recovered from metal scrap, which plays an increasingly important role in the world. Metals after being produced, either from primary or recycling resources, have to be further refined or manufactured into various types of alloys and finally shaped into different products for the end-users. Since the end-user discards products the contained materials find their way back into the resource cycle as scrap. Therefore, controlling the metallurgical reactors also controls, in a much broader sense, the material quality in the complete metals cycle, from the production phase, to the end-use phase, up to the recycling phase (Reuter et al., 2003). The recycling phase includes separation of materials into saleable intermediate products, which are reintroduced into the production phase as a recycling resource. Therefore, the metallurgical processes in each unit operation in the metals production and processing chain have to be controlled, so as to achieve optimal performance of high product quality, low energy and materials consumption, and low environmental impact."

Jan 1, 2003

By A. De1

Because of the extremely low utilization of strain energy in the breakage of solid particles, the energy efficiency prevalent in comminution technology is extremely poor. Schoenert considered that single-particle comminution under slow compression is the most energy-efficient mode of comminution and that energy efficiency should be compared to that. The usual method for grinding minerals and cement has been the ball mill, in which the hit-and-miss aspect of loose-bed comminution severely reduces energy efficiency. The fine grinding of minerals is a particularly energy-intensive process. Schoenert showed that the energy consumed in the comminution of particles in confined beds is second only to that of single-particle comminution under slow compression and developed the method of conducting particle-bed comminution continuously in a high-pressure roll mill. Since its first industrial installation in 1985, the high-pressure roll mill has established itself as the comminution device of choice for significantly improving the productivity and energy efficiency of size reduction from coarse size feeds down to products finer than 20 microns. The first of several hundred installations were in cement plants. The preliminary design and optimization of the industrial operation of high-pressure grinding roll (HPGR) systems, owing to the continuous nature of the device, cannot be efficiently done through laboratory experiments and needs to be achieved through proper system modeling. While the energetics of size reduction in high-pressure grinding rolls has been modeled very well, no model exists for the macroscopic variables in HPGR comminution. In high-pressure roll mill grinding, size reduction results from confined particle-bed comminution under compressive stresses such that the daughter particles produced are highly fractured, stressed, or otherwise weakened. This paper attempts to relate the comminution / compaction behavior for confined particle-bed under compression in a piston-die press with the macroscopic variables in HPGR comminution. A model describing the pressure-densification relationship is presented and used to accurately simulate the macroscopic variables in high-pressure grinding rolls, utilizing experimental data for particle-bed comminution with the piston-die press. The accuracy of the predictive simulations strongly suggests that, starting with a few batch-mode laboratory-scale experiments, it should be possible not only to identify the optimal operating conditions for existing operations but also to successfully design new industrial high- pressure grinding roll systems.

Sep 1, 2012

By R. M. Zhao

The process conditions and mineral characters of cleaning separation stage in magnetite concentration plant are studied in the paper, and the affecting factors and the methods to increase the concentrate grade are analysed and given. The BKJ cleaning special drum magnetic separator is developed specially for the cleaning stage according to process conditions and mineral character. The separation mechanism, structure characters, separation process and excellent adaptability of BKJ special magnetic separator are described. The results in Zhangjiawa Concentration Plant show that the BKJ special drum magnetite separators play an important role in increasing the concentrate grade and improving the economic benefit.

Jan 1, 2014

"The most common agglomeration technique in iron and steelmaking is sintering, which requires the use of iron ore/concentrate mixtures, limestone and dolomite as fluxes and coke as fuel in order to produce the required melt at high temperature to cause agglomeration of the particles. Sinter feed blends containing high proportions of magnetite concentrate are difficult to granulate and to produce granules of high permeability, and sufficiently robust quasi-particles for successful sintering operations. Since the granulation of iron ore sinter feed requires no use of a binder, the added fluxes play a vital role in holding the granule particles together until they sinter. The fluxes also help to improve the granule quality and control slag composition in the blast furnace. It is well-known that the particle size distribution of the fluxes affects the granulation effectiveness and green bed permeability which determine the productivity, physical and metallurgical properties of the granules and sinter. Hence it is necessary to understand the role of flux particle size on granule properties so as to improve the granulation of iron ore sinter feed blends containing high magnetite concentrate. In this study, laboratory granulation experiments have been carried out on iron ore sinter feed blends containing high proportions of magnetite concentrate at different addition levels of limestone and dolomite mean particle sizes, to understand the influence of limestone and dolomite particle sizes on granulation rate processes and granule properties.INTRODUCTION Increases in iron ore production to meet the global demand for iron and steel products has led to the depletion of high grade iron ores and thus the current utilisation of low grade iron ore fines and concentrates. However, sinter, pellets and the lump are the required feed types used in the blast furnace. The high basicity sinter is the main iron bearing feed accounting for 70-85% in the blast furnace due to its good metallurgical and mechanical properties that allow high productivity, efficient processes and low production cost (Adam et al., 2017)."

Jan 1, 2018

By Dmitriy Makarov

The paper presents the modeling and analysis of oxidation of pyrite copper-zinc ore samples from the Letnee, Yaman-Kasy and Valentorskoye deposits. It is found, that the oxidized samples contain copper and zinc sulfates that are leached under the sample and water contact. It is shown, that sulfide floatability is decreased by the longer-term oxidation.We advise to improve nonferrous metals recovery by joint leaching and ultrasonic treatment of oxidized compounds. Study of the geotechnological processes of non-ferrous metal extraction, on the basis of two copper-zinc ore deposits shows, that heap leaching is of little use for the ores of the Letnee deposit. Leaching results for the Yaman-Kasy ore showed more promise.

Sep 1, 2012

By A. V. Zimin

It is a well-known fact that usage of reverse cationic flotation in magnetite ores processing enables to improve the quality of magnetite concentrates. We designed an iron ore concentrate technology (with 70 -71 % of iron) including reverse cationic flotation in pneumo-mechanical flotators RIF (developed by RIVS Corporation, Russia) with good biodegradable etheramines as collectors for flotation of quartz. Practical application of high biodegradable flotation reagents decreases environmental impact risk of objects and enterprises of mining industrial complex. This work presents results of development of flotation technology for production of high quality ferruginous concentrates from magnetite ores of Russia and Ukraine deposits. Keywords: magnetite ores, reverse cationic flotation, ferruginous concentrates, pneumatic-mechanical flotation machines, environmental impact

Sep 1, 2012

By E. Hulthén

Cone crushers are used in the mineral, mining, and aggregate industry for fragmentation of rock materials. Control systems for cone crusher settings are widely used to compensate for wear and to protect the machines. The eccentric speed in a cone crusher affects the number of compressions the material is exposed to and thus the particle size distribution of the product. Eccentric speed also affects crusher capacity. However, the speed of the crusher is mostly fixed, because speed changes must be made by shifting pulleys, a process which is quite time-consuming. By applying a frequency converter, which has decreased in cost during recent years, it has become possible to adjust the speed continuously. By also applying mass-flow sensors to the process, the crusher can be run optimally to yield the most sellable products in a given moment. Existing systems normally only protect the machine. The sensors can be mass-flow meters, e.g., conveyor-belt scales. To analyze data from the process and calculate the appropriate value for the speed, an algorithm has been developed. The developed algorithm was tested and evolved at a crushing plant for aggregates that produces around 350 kton a year. The algorithm was implemented in a computer that could communicate with the frequency controller, retrieve data from four mass-flow meters, and also interact with the opera-tor. The computer was reachable over the Internet for the researchers at Chalmers and the algorithm was tuned and improved on-line. The result is a crushing stage that consistently and maximally produces the most desirable product. The performance (yield of required products) increased by 4%. As a bonus, the lifetime of the mantles increased 27% on the evaluated crusher.

Jan 1, 2014

By Y. Foucaud, C. Eswaraiah, L. Filippov

Enhanced gravity separators such as Falcon concentrator which uses additional centrifugal force, are the most common gravity concentration techniques used for fine particles processing. Hence, understanding the kinetics and separation mechanisms within these separators is of paramount interest. Recent research yielded a predictive physical model for the Falcon Ultra Fine (UF) which however does not explain some results obtained with industrial ores. This study aims to identify the mechanisms involved in Falcon UF separation with the objective of confirming or rejecting the hypotheses on which the current model is built and suggesting potential points of improvement. The Falcon UF kinetics is investigated through the processing of complex low-grade and fine-grained ores from the Altenberg tin deposit (Germany), the Tabuaço tungsten deposit (Portugal) as well as a synthetic iron ore. Saturation tests are performed on the Falcon UF by controlling the separation efficiency in terms of recovery and enrichment ratio with time or feed mass. Results show an evolution of Falcon UF performance with time in contradiction with the stationary separation hypothesis on which the physical model is based. Observation of the concentrate bed suggests the presence of erosion figures in furrows which may play locally an active role in the separation. In terms of Falcon UF separation timing, three phases can be distinguished. First, upon initial feeding of the bowl, a bed quickly grows unselectively and ultra-fine particles are ejected from the bowl until the bed reaches its final profile. Next, actual separation occurs with selective concentration of dense particles. Finally, capture sites saturate and recovery drops. The evolution of partition curves over time confirms the existence of two separation mechanisms. First, differential particles settling within the flowing film responsible for the ejection of small size particles during the whole separation cycle which is already accounted for in the physical model. The second mechanism involved may be explained by the action of lift force, neglected in the physical model, which acts preferentially on coarse particles deposited at the surface of the bed resulting in coarser particles being rejected in the tailings. Hence, the addition of a lift force component to the existing model is suggested to account for this second separation mechanism.

Jan 1, 2018

By Ernesto de la Torre, Karla Velín, Alicia Guevara

"The following study shows the improvement and simulation of a gold recovery plant of 24 t/day of capacity by gravity concentration, flotation and leaching. The ore processed had grades of 6 g/t Au, 15 g/t Ag, and 0.69 %Cu with the mineralogy consisting of 2 %chalcopyrite, 12 %pyrrhotite, 7 %plagioclase and 50 %quartz. The recovery process starts with crushing the ore followed by grinding it further in a ball mill. The ground ore is then concentrated in a Falcon centrifugal concentrator with concentrate being processed by amalgamation process. Gravity tails are sent to a flotation circuit where the copper minerals and some gold are concentrated. Lastly, the flotation tailings undergo cyanidation for gold recovery. Currently, the overall recoveries are 82.8 %Au, 49.6 %Ag and 99.1 % Cu. The optimization was developed in the laboratory using a Wilfley table by gravity concentration. Flotation tests in the laboratory were performed using potassium amyl xanthate and pine oil. Lastly, cyanidation was then performed on the flotation tailings. The results showed the optimum concentration of sodium cyanide in cyanidation is 2 g/L, which produced an increase in gold recovery from 30% to 44%. The reduction of diameter particle from 132 to 80 µm also produces an incremental recovery of gold and silver from 11% to 21% Au and 0.4 to 3% Ag in gravity concentration. Likewise in the cyanidation the recovery of gold and silver has shown a rise from 44 to 62% and 8 to 32% for Au and Ag respectively. However, the flotation method the gold recovery is reduced from 68 to 30% Au by reducing the particle size. Computer simulations using the programs, Moly-Cop and ModSim were performed to determine optimum parameters for the recovery of precious metals at the gold recovery plant."

Jan 1, 2014

By Sergey Dyachenko

"Following the adopted strategy for making the production modern, efficient and environmental friendly the Company completed a stage of the integrated program aimed at reconfiguration of its processing capacity.Upgrade of the Talnakh Concentrator with commissioning of two start-up facilities (SF) allowed an increase of 30% in its ore processing capacity up to 10 mtpa. In addition to a new high-tech equipment installed, a new concentration process was adopted offering the main advantage of 25-30% reduction of sulfides in concentrate. New concentration technology enabled the total amount of produced nickel concentrates (from Norilsk and Talnakh Concentrators) to be processed at upgraded smelting facilities of Nadezhda Metallurgical Plant and allowed decommissioning of smelting capacities of Nickel Plant resulting in emissions reduction by 30%.Nornickel plans to boost the capacity of Talnakh Concentrator to 18 mtpa by 2022, after commissioning of the 3rd SF. This will provide a shorter route for ores transportation from Talnakh mines along with improvement of cost/performance ratio of ore processing through the usage of the modern equipment and optimized concentration flow scheme. Total capacity of Talnakh Concentrator will be sufficient to process ores from Talnakh deposits with planned upstream assets development taken into account. Volume of ore mined from Norilsk deposits to be processed at Norilsk Concentrator will be also increased.Upgrading the crushing section at Kola MMC Concentrator in 2015 provided finer particles of the crushed ore, resulting in 6.6% increase in specific capacity of ore mills as well as 1% higher recovery of non-ferrous metals due to improved liberation of ore minerals.In 2015-2017 the Company was actively engaged in optimization of existing process flow schemes and parameters of Kola MMC, new high-performance reagents were adopted for concentration process, namely, collectors, depressors, flocculants. These measures allowed the Concentrator to reduce its annual operating unit costs and ensure sustainable production of concentrate with the lower grade of the incoming feedstock.Launched in October 2017, Bystrinsky GOK’s Concentrator was 3D designed and received a range of advanced technological solutions.All design process procedures and technologies rolled-out at the Company’s concentrators were developed by Russian R&D institutes, with the key role of Gipronickel Institute, R&D Service of Kola MMC and Polar Division's in-house Engineering Support Centre."

Jan 1, 2018

By Robin B. Batterham

"Since the 1970?s we have seen a marked corporate response in terms of the environment. In part this has come from regulation but it has largely come from stakeholders and the community. Rising expectations have in general been met. We now see a similar trend towards sustainability. At the same time, the importance of mining to the share market has decreased drastically and with that decrease has come the requirement for the mining sector to show returns similar in manner to other sectors. While rationalisation can achieve some progress towards these goals, the long-term requirement is for innovation, as it always has been. This paper looks to the logical goal of innovation within a sustainable mining framework and targets the removal of the desired metal values with minimal environmental footprint. It is suggested that broad ranging alliances will be necessary, particularly amongst the R&D suppliers, to achieve this goal. Industry will need to take an active role given the recent global restructuring.THE MARCH TO SUSTAINABILITYSince the 1970?s there has been an increasing corporate response on environmental matters. We have moved from matters environmental being issues relevant only to minority groups through a series of attitudinal changes by management. Whilst there have always been examples of excellent environmental performance, for many in the 70?s spending money on improving the environment beyond some minimal level was seen as a distraction from production or treated in a similar way to donations to the community. There is little of that attitude these days, as most mining companies have long since regarded the environment as a core business direction. Indeed, for some years one could note an escalation in matters of environmental reporting to the extent that the environmental performance of companies is now very public. In some cases, NGOs have even been invited to help certify and audit the reporting standards. Similarly with health & safety.There is now a rising expectation on the part of the community that social matters will also be given the same level of support as health, safety and the environment. This time around it would appear that the mining industry is at the leading edge of sustainability. The Global Mining Initiative (Global Mining, 2002) and the contributions to the Rio World Summit on Sustainable Development (Rio +10, 2002) suggest that sustainability is being taken very seriously by the mining industry. For sustainability it is convenient to use the Brundtland (1987) definition. This definition has widespread acceptance with governments, industry, environmental groups, financial institutions and individuals as a direction against which our activities and plans can be measured."

Jan 1, 2003

By T. Bhambhani, O. Yavuzkan, D. R. Nagaraj

"The recovery of oxide Cu minerals by flotation is a longstanding challenge in the minerals industry, especially for high acid-consuming ores which would not be economical for direct acid leaching. Sulfidization (often using controlled potential sulfidization or CPS) using NaSH (or Na2S) followed by flotation using traditional sulfide collectors is the widely used technique. CPS has certain limitations: a) inability to recover certain oxide Cu minerals because they are refractory to sulfidization, b) high consumption of NaSH (or Na2S), and c) potential health and safety hazards associated with NaSH (and Na2S). Flotation of oxide copper minerals using alkyl hydroxamate (AHX) collector has been studied extensively. Investigations using single minerals and laboratory ore flotation have been conducted in the past to demonstrate the efficacy of alkyl hydroxamates. The technology has been used intermittently in plants. One of the main challenges in plant use has been quantifying the true potential for alkyl hydroxamates for recovery of various oxide Cu species in complex and variable ore systems and identifying the most suitable conditions for optimal use. Quantitative mineralogical analysis using QEMSCAN was used in this study to characterize flotation products lab flotation samples. Analysis of concentrates and tails from hydroxamate flotation and CPS flotation stages demonstrated that certain oxide Cu minerals respond exclusively to alkyl hydroxamates and not to CPS. The hierarchy of interaction of AHX with the various oxide Cu minerals could be inferred from these studies. Finally, these studies also allowed quantification of a group of minerals species, which (erroneously) report as part of the Acid-Soluble Cu [ASCu] but cannot be recovered by flotation, thereby facilitating an estimation of the true recovery potential for alkyl hydroxamate.INTRODUCTIONCopper that is economically recoverable occurs in three major types of ores, which are defined by the modal mineralogy of Cu. For sulfide ores, Cu occurs as sulfide minerals and is satisfactorily recovered by flotation using sulfide collectors. Non-sulfide ores, which contain Cu in the form of oxides, phosphates, carbonates and silicates, described in the industry as “oxide” ores (or ores containing “acid-soluble” Cu or ASCu), are currently treated using hydrometallurgy, which involves leaching with dilute sulfuric acid followed by solvent extraction and electrowinning, unless the ores contain acid consuming gangue minerals such as dolomite. For mixed sulfide-oxide ores (i.e. containing both sulfide and oxide Cu minerals) that do not contain acid consuming gangue minerals, Cu values are easily recovered by flotation of sulfide Cu minerals followed by leaching of oxides (only when a leach plant is available). However, when the ore contains acid consuming gangue minerals flotation is required to recover both sulfide and oxide Cu minerals."

Jan 1, 2018

By P. Somasundaran, G. Anastassakis, Z. Pan, D. R. Nagaraj

Gums are often used as depressants for talceous gangue minerals in the flotation of nickel and platinum bearing ores. However, the mechanisms of gum adsorption on talc are not clearly established. In this work, adsorption of guar gum at the talc-solution interface is investigated using spectroscopic and allied techniques. Guar gum adsorption on talc is not affected significantly by changes in solution conditions such as pH and ionic strength. Electrokinetic studies showed that guar gum decreased the negative zeta potential of talc but did not reverse the charge. Fluorescence spectroscopy studies conducted to investigate the role of hydrophobic bonding using pyrene and dansyl probes showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Urea, a hydrogen bond breaker, reduced the adsorption of guar on talc to the same extent as that for guar/alumina system, in which hydrogen bond plays an important role. All of the above results suggest that one of the main driving forces for guar adsorption on talc is hydrogen bonding rather than electrostatic or hydrophobic force.

Jan 1, 2003

By Yuhua Wang, Huilan Yang, Yanqing Jiang, Dongfang Lu

"Generally, the concentration of bauxite flotation tailings is around 10%, a large amount of water in tailings needed to be recycled in the flotation process. Sedimentation and dewatering properties of tailings were investigated under different conditions. Surface high negative charges on mineral particles are the key factor to destroy the settlement of tailings when the pulp pH is around 8.9. Hence, the modification of pulp pH around 7 is necessary to the diminution of the repulsive force between mineral particles and then the acceleration of sedimentation of tailings. Anionic polyacrylamine with molecular weight of 14 million is the best flocculant for the settlement of tailings in all tested polyacrylamines. P-toluene sulfonic acid shows better properties than hydrochloric acid for pulp pH adjustment when anionic polyacrylamine with molecular weight of 14 million is used as flocculant. Although the flotation of diaspore is depressed in the presence of polyacrylamine using sodium oleate as collector, but the recycling water traded by the combination of ployacrylamine and p-touenesulfonic acid does not show the depression effects on the flotation of bauxite ore. The lower residual content of polyacrylamine in recycling water treated by the combination of ployacrylamine and p-touene sulfonic acid plays an important role. INTRODUCTION Generally, the waste water generated from mineral processing plant is usually treated by sedimentation, oxidization, electrodialysis, ions exchange, active carbon adsorption and flotation technology, and the treated water is also used again in the industrial process. Flotation was adopted widely to improve the quality of bauxite from low grade diasporic bauxite in China. For flotation, the grinding fineness of bauxite is over 90% -0.074 mm, sodium carbonate and sodium hexametaphosphate were used as regulators, so the tailings pulp is very difficult to settle and be dewatered (Y. Wang et al., 2004; Y. H. Wang et al., 2007; Wang Yu-hua et al., 2008; Wang Yuhua et al., 2011). The water recycling of bauxite tailings are becoming the highlight for the industrial application of the flotation process for bauxite ore. Researchers in China shift their attentions onto this topic."

Jan 1, 2018

By Jochen Petersen, David G. Dixon

"Although heap leaching may be perceived as a somewhat low-tech route for the extraction of low-grade minerals, the underlying physical, chemical and biological processes are in fact extremely complex. There has been increased interest in heap leaching of sulphide minerals in recent years with the advent of controlled bio-heap leaching, and the need to mine more marginal ore deposits.A detailed investigation into the dynamics of heap leach processes has provided much insight into the underlying complexities, and has led to the development of a sophisticated modelling tool. Some of the features include mineral kinetics, particle level effects, bacterial growth, oxidation and adsorption, gas adsorption, pore diffusion, bulk advection, gas balance and heat conservation.Two case studies are presented which illustrate specific features of the model for different applications and how these have helped to identify key areas of concern. In each case the model has proved as an invaluable tool either for the improvement of existing heap leach practice or for the development and assessment of novel applications."

Jan 1, 2003

By Dilip Kumar Mohanty

In today?s world, Sustainability is the key issue before the mankind. With the ever-increasing population & unimaginable boost in industrial growth to cope up with a steady increase in demand and fast change in life style of a human being, the natural resources are exploited to such an extent that the very existence of living beings in this earth planet is threatened. In such devastating situation, the concept of Sustainability emerges out as a great savior. This concept focuses on minimum/ judicious use of natural resources, thereby preserving the resources for future generation while meeting the bare minimum requirement of the present generation. For an emerging economy like India, Mining and Mineral based industries form the back bone of our economic development. Thus, sustainability of mining and mineral processing industry has a far reaching impact on sustainable economic development of our nation. While at a macro-economic level, we have to strike a balance between economic development vis-à-vis socio-economic & environmental impacts, Industries have to ensure judicious and frugal use of natural resources by making use of energy efficient plants & machineries and adopting befitting technology for reduction & recycling of waste. In the context of the above, it would be interesting to look into the sustainability measures taken up by National Aluminium company (Nalco) at its Crushing & conveying plant at Panchpatmali Bauxite Mine, which is incidentally Asia?s largest Bauxite Mine. In the backdrop of the above stated facts, in this paper the authors make an attempt to bring out the sustainability issues in areas of energy conservation, environmental impact/pollution vis-a-vis mitigation measures adopted in crusher & conveyor plant of Panchpatmali Bauxite Mine & CSR / peripheral developmental activities undertaken by Nalco to mitigate the socio- economic impacts. Keywords: sustainability, energy efficiency, recycle, csr, peripheral development

Sep 1, 2012