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By Yang Zhao, Tao Xiu-xiang, Chen Song-jiang

"China is rich in low-rank coals that account for 45.68% of existing coal reserves in China. The clean and efficient utilization of low rank coals is of great significance for ensuring the effective energy supply and promoting economic development and environmental protection. In order to solve the difficult problem in flotation of low rank coal, it has become the focus of research in the related field that oily bubbles instead of air bubbles are taken as a carrier in flotation to improve the attachment efficiency and recovery of low rank coal. In this paper, low rank coal slime collected from Shendong mining area was used as the experimental material, and it focused on the characteristics of oily-bubble flotation process of low rank coal. Additionally, difference in conventional flotation and oily-bubble flotation was discussed. The induction time between air bubbles, oily-bubbles and fine low rank coal particles was measured. The results indicated that the induction time between oily-bubbles and coal particles was obviously lower than that of air bubbles. By comparing the foam height of air and oily bubbles, it was found that the amount of oily bubbles is less than air bubbles, causing relative low flotation rate of oily-bubble flotation at initial stage. Besides, the maximum foam height and half-life of air bubbles and oily-bubbles were measured respectively. The results showed that the stability of oily-bubbles was higher than that of air bubbles, which is benefit for the enrichment of concentrates. The clean coal water recovery of oily-bubble flotation is lower than that of air bubble flotation, which indicated oily-bubble flotation is lower in water entrainment. INTRODUCTION China is the largest energy consumer in the world, accounting for 23% of global energy consumption in 2016 and 27% of global energy consumption growth. Whereas coal is taken as the major primary energy source and its share of China’s primary energy consumption is 62% in 2016, in which the low rank coals, such as lignite, long-flame coal, weakly caking coal, and non-caking coal, accounted for about 50% of total coal production capacity (China’s energy market in 2016, BP). Moreover, the exploitation and utilization of low rank coals and other coals that are difficult to float have been an important strategy for China’s sustainable development of the coal industry (Liu et al., 2014). However, the combustion of low-quality coals leads to a serious environmental pollution. In addition, the deterioration in geological conditions of coal resources, and the increasing improvement in the mechanization for mining significantly caused the increased amount of fine coal."

Jan 1, 2018

By H. Gallardo, J. Yianatos

Flotation is a separation process in which mineral recovery depends on the particle surface properties. The selective collection of particles by air bubbles requires hydrophobic mineral surfaces. Hydrophobicity can be selectively induced on a valuable mineral surface by means of reagents. For this purpose, it is required that mineral grains in the ore become physically liberated or exposed in the particle surface after grinding. The grinding process generates three types of particles according their exposed surface in the floatable mineral: locked particles (0-10%), associated particles (10-90%) and liberated particles (90-100%). Locked particles have low floatability, and they typically show low recovery (<20%), while liberated particles have a high floatability and can be easily recovered (98-100%) at different particle sizes (10-150 µm). The main challenge in the flotation process is the recovery of associated particles. These particles typically have recoveries of 20-80%, but strongly depend on the particle size, particle surface liberation and collector dosage. Recent studies on particle floatability by size-liberation have significantly contributed to improving the characterization of flotation processes. In this work, a study of flotation recovery of associated particles of 10-90% liberation is presented for particle sizes (10-150 µm) and collector dosages (5-40 g/ton). In this work historical data on galena recovery based on particle cross-section composition of galena was used, assuming they represent an acceptable estimate of particle surface composition, as shown by some previous researchers. The results showed that galena recovery can be well represented by a model consisting of the interaction of a linear function and a Gamma distribution function to account for the liberation and the particle size effects. Consequently, an alternative approach for modelling the recovery of associated mineral (10-90% liberation), with a reduced number of parameters, was developed and validated.

Jan 1, 2018

By X. H. Zhou

Column flotation is being widely adopted for fine particle treatment by the mineral processing industry due to its simplicity of structure, high efficiency and good separation performance. Cyclonic static micro-bubble column flotation (FCSMC) is an innovative column separation technology that has been successfully applied in the coal preparation industry in China. Recently, the application of this equipment has been further expanded to the separation of several minerals such as fluorite, copper, iron, etc. The bottom of the FCSMC is a cone in which cyclonic field is generated when circulating pump is injected tangentially into the column. The unique cyclonic structure is believed to help enhance the column separation performance. Since the FCSMC is a new flotation device, little work has been done to understand the fundamentals of this technology. In this research, a computational fluid dynamics software, ANSYS/ FLOTRAN, was employed to simulate the flow field of a lab FCSMC system (F0.2 m, F3.0 m by length.) The distribution patterns for velocity field and flow field were investigated under single phase condition. It has been found that axial velocity of the slurry decreases and becomes stable along the height of the column from bottom to top, and the slurry performs as a descending flow pattern. Another observation is the velocity fluctuates vigorously near the wall due to wall effect. Compared to axial velocity, the radial velocity distribution is smaller and more complicated. The basic pattern is that on a given cross section of the column radial velocity increases from the wall to the center and it the velocity changes greatly around the center. Under the condition of column height less than 0.8 m, the axial velocity is negative and it directs from the wall to the column axis. When column height is higher than 0.8 m a reverse pattern is obtained, i.e., axial velocity is positive while directing from column axis to the wall. Special efforts were directed to investigate the tangential velocity pattern. Results indicate that the tangential velocity patterns of different cross sections are similar and showed a symmetrical distribution. Tangential velocity distribution concluded two zones: outer whirlpool and inner whirl-pool. And, interestingly, it has been found that on different cross sections the highest tangential velocity always occurs at the same position of the cross sections.

Jan 1, 2014

By P. A. Bepswa

A numerical study done to test the efficacy of heuristics developed for the design of measurement networks for high precision metallurgical accounting is presented in this paper. The heuristics considered were designed to maximise variance reduction of terminal stream measurements through data reconciliation for observable linear flow systems. A complex metallurgical process flow sheet from the mineral sands industry was used as a case study. Monte Carlo type simulations coupled with a non-linear programming based steady state data reconciliation algorithm were used as tools to investigate the heuristics. The results obtained suggested a close correlation between magnitudes of measured variances and the respective levels of variance reduction obtained through data reconciliation for both internal and terminal streams. It was observed that variance reduction through data reconciliation was maximised for terminal stream measurements in networks characterised by high precision measurement of internal streams and/or in flow sheets characterised by high ?stream to node ratios?. Terminal streams attached to highly interconnected parent nodes were observed to experience higher reductions in variance compared to terminal streams attached to less interconnected parent nodes. The results generally highlight the additional benefits of highly interconnected flow sheets and high precision internal stream measurement regimes on the maximisation of variance reduction of terminal stream measurements through data reconciliation. These findings are significant to metallurgical accounting and to process accounting applications in general in that they provide a conceptual basis for design decision making regarding the construction of measurement networks aimed at maximising variance reduction of targeted streams through data reconciliation.

Jan 1, 2014

By J. J. Liu

In the Bayer process, control of alumina trihydrate particle size, oxalate stability and morphology and foaming is crucial for improving the yield and quality of alumina trihydrate. One way to economically achieve such control is to employ specifically developed chemical additives, termed, crystal growth modifiers (CGM?s). In this paper, the mechanism of action and practical application of CGM?s in the Bayer process are summarized. The application of CGM additives allows for both enhanced agglomeration and secondary nucleation control, and hence coarsening of the particles. Current research efforts have utilized the information gained from mechanistic studies to enhance the performance of CGM products. It was demonstrated in both laboratory tests and industrial operations that the newly developed CGM formulations have a range of properties with enhanced performance, compared to the current commercial products.

Jan 1, 2014

By T. J. Chen

Vanadium-beard bone coal is one of important vanadium resources in China.To extract vanadium tailings from Stone coal is produced after extracted vanadium from stone coal through the roasting, leaching and other processes. About 120-150 tons of tailings will be produced in extracting 1 ton of vanadium pentoxide. A lot of tailings that are willfully piled up have caused serious environmental pollution and wasting of resources; it is therefore necessary to realize its resource utilization. This study increases the activity of vanadium tailings by means of alkali fusion, and then uses different alkali activators to react with vanadium tailings so that geopolymer with high value added is produced. Sample of geopolymer is acquired from a mixture containing vanadium tailings, alkali activators, water and a little sodium aluminate through compression-molding process under 20MPa pressure. After cured in room temperature for three days, the maximum compressive strength of the sample can reach 36.2MPa. XRD analysis indicates quartz, the major crystal phase in vanadium tailings is decomposed,and the activity of vanadium tailings is heightened. FTIR and SEM analyses show: structural change having an important impact on the mechanical strength of geopolymer occurred during the process of vanadium tailings generating geopolymer.

Sep 1, 2012

By Sudarshan Martins, Peter Radziszewski

"Tumbling mills are machine, operating in non-equilibrium, capable of applying forces on the ore contained within, causing the ore to break down. The action of the mill on the ore is very inefficient, producing a large quantity of heat. The inefficiencies of the mill drive the desire for improvement, spawning research and development activities. Given the non-equilibrium nature of the mill, the theory of Large Deviations is proposed as the framework that captures the state of the mill. The theory of Large Deviations allows for the determination of the rate function and the scaled cumulant generating function (SCGF), for systems in either equilibrium or non-equilibrium. Powerful connections can been made between familiar concepts of statistical physics and the concepts introduced by the theory of Large Deviations: entropy can be associated with the rate function; the scaled cumulant generating function with the free energy. It is shown that observables, compatible with Large Deviation theory, can be identified for the tumbling mill. Here, the time series of the energy associated with an element of the charge is such an observable. Furthermore, using some experimental data, it is shown that the time series of the energy can define a rate function, thereby describing the system within the Large Deviation framework. Finally, a discussion of the results is given, particularly how this theory can be further developed for tumbling mills."

Jan 1, 2014

By Liang Dianyin

In this paper, the molybdenite flotation tailing of cleaner-scavenger bank which has a mass of very fine particles has been taken as raw ore to be processed by flotation with/without ultrasonic. The effect of ultrasonic frequency, intensity, processing time and uploading location on molybdenite flotation efficiency is investigated by four-factor three-level orthogonal experiment, and the effect significances of these ultrasonic variables to molybdenite flotation efficiency have also been evaluated. Single-factor analysis of variance is conducted to investigate whether the effect of ultrasonic on molybdenum ore flotation efficiency is significant or not. The samples extracted from different ore species in different time have been mixed to analyze the particle size. The results show that the particle size of +38µm in concentrate obviously increases while the particle size of -25µmobviouslydecreaseswith ultrasonic, which means that ultrasonic is good for flotation due to sludge removing effect. Keywords: ultrasonic, flotation efficiency, sulfide ore, tailing, grade, sludge removing

Sep 1, 2012

By Q. X. Li

The state discharge standard for arsenic-containing wastewater which is the first kind of pollution is less than 0.5 mg/L. In fact, in a certain company, the acidic arsenic-containing wastewater in non-ferrous smelting was as high as 860 mg/L, which is far beyond the state discharge standard. Obviously, the direct release of this wastewater without further treatment would result in great hazards to the ecological environment. To aim directly at the characteristics of acidic arsenic-containing wastewater, in this study, two steps of treatment including oxidation-flocculation and removal fluoride by mixing alkaline neutralization were suggested. Through analyzing various influencing factors in treatment effects, the optimum technical conditions were obtained. The sediments after treating were recyclable and the secondary pollutions can be avoided. Moreover, the results also show that, all indexes of the effluent after treating are lower than the First Grade Standard of Integrated Wastewater Discharge (GB 8978-1996). This novel method has advantages of short flow sheet, easy operation and low cost.

Jan 1, 2014

By U. S. Chattopadhyay

The estimated requirement of the nation by the year 2020 is approx. 80 Mt of steel and more than 0.2 million MW installed capacity of the electricity, thereby increasing the consumption of the coking and non-coking coal, which is expected to be in tune of about 75 Mt & 500 Mt respectively. One of the major deleterious factors in achieving the goal is the deteriorating quality of the feed coal used in both steel and power industries. Indian coking coals, in general, are typified by high ash, high inert (both organic and inorganic), low rank, low reactive macerals content, heterogeneous petrographic make-up, inferior coking properties and poor amenability to washing, thereby necessitating suitable washing measure. Coke-based steel industries in India require washed coking coal containing ash % varying between 17-19. The situation demands taking on immediate challenges to fill up the gap between the requirements and supply of coking coal. This paper reviews the R&D attempts in this laboratory and throws light on the key measures as long-term solution to the problem. Search for alternative source of coking coal, like LVC coal and their judicious preparation technology. The low volatile coking coal (LVCC) constitutes about 50% of the total coking coal reserves in India. These coals are characterized by high raw coal ash content (37 to 40%) and very difficult washability potential. If these coals are treated in the existing washeries, which are generally 2 or 3-product systems, the cost of clean coal is high as the byproduct sale value is low. It has been proposed to produce a new type of by product, which enjoys high demand and good coking properties.

Sep 1, 2012

By H. Deng

Oxidized zinc ores are the main source of zinc metal except sulfides. To have a better understanding about the performance of smithsonite and the main gangue, quartz, in flotation, the aggregation behaviors of smithsonite and quartz in water were confirmed by different techniques (sedimentation tests and optical microscopy). The experimental results show that smithsonite and quartz particles aggregate in the pH range 7.5-11. The results of zeta potential suggest that the aggregation does not correlate with the DLVO theory, when the iso-electric point of smithsonite and quartz is 8.0 and 2 respectively. When the solution pH is less than 8.0, smithsonite has an opposite charge to the quartz particles. Electrostatic adsorption makes effort on these two kinds of particles according to DLVO theory. Whereas, solution chemistry calculation shows the pH range 8-11 corresponds to hydroxide formation, suggesting that this is the species responsible for aggregation. And their concentrations are much higher in sodium hydroxide system than that in sodium carbonate system. Aggregation of smithsonite and quartz due to the flocculation action of zinc hydroxide is proposed.

Sep 1, 2012

By K. W. Stöckelhuber, A. Wenger, H. J. Schulze

"An important elementary step of the flotation process is the forming, drainage and rupture of a thin intervening liquid film between bubble and mineral particle.After the encounter of the bubble with the solid surface a wetting film is formed. The initial thinning of this film is driven by the capillary pressure inside the bubble. When the film has reached a certain thickness rupture can take place.There are two possible mechanisms describing this process:-, Growing fluctuation waves (spinodal dewetting) on fluid interfaces under the influence of any kind of attractive forces (electrostatic, van der Waals). -, Nucleation inside the film.Metastable wetting films on negatively charged, hydrophobic glass surfaces (gaseous phase methylated), or on hydrophilic, positively charged glass surfaces (with Al3+ ions), have been analysed by means of the kinetics of film thinning according to the Reynolds law. These experiments demonstrate that both mechanisms can be responsible for the rupture of a thin wetting film. In the case of hydrophobic surfaces the nucleation mechanism is preferred; in the case of opposite charged silica surface the capillary waves mechanism due to an attractive electrostatic double layer force between silica and air bubble takes place.Hereby the existence of a long range hydrophobic force. on a hydrophobic surface can be excluded. The apparent interaction can be explained by the presence of gas nuclei formed on heterogeneous surface sites. The results provide deeper insight into the mechanisms of wetting film stability, adhesion process in flotation and droplet coalescence."

Jan 1, 2003

By I. Dymov

"The extractive metallurgy of precious metal ores involves gravity concentration, flotation and cyanide leaching. Pre-oxidation, such as roasting, autoclaving, bacterial oxidation and other techniques, is required for processing refractory ores. Selection of the process is mainly driven by the grade, reserve and mineralogy of the target elements. The concentrations of precious metals in the crust are extremely low and highly variable, resulting in ore variability in many gold, silver and PGE deposits. More importantly, precious metals in an ore may occur in two or three forms (i.e. microscopic, submicroscopic and surface-bound), making ore processing of precious metals extremely challenging. The objective of geometallurgy and process mineralogy is to reduce and minimize the technical risk in project evaluation, process selection, mine planning and production forecasting through geometallurgical modelling, representative sampling and subsequent systematic mineralogical characterization and metallurgical testwork. Geometallurgy is a technique to document variability within an orebody and quantify and evaluate the impact of many factors including geology and mineralogy on grinding, flotation, leaching and metal recovery processes, while mineralogy is one of the major predictive and trouble-shooting tools for many new mineral projects and operating mines. This paper presents an overview of fundamentals, methodologies and techniques applied in geometallurgy and process mineralogy and highlights the importance of both disciplines in process selection and plant optimization with applicable case studies. INTRODUCTION Precious metals, including gold, silver and platinum group elements (PGE) occur in various geological settings and ore types. The concentrations of these metals in the crust are extremely low and highly variable, resulting in ore variability in many gold, silver and PGE deposits. More importantly, precious metals in an ore may occur in two or three forms (i.e. microscopic, submicroscopic and surface-bound), making ore processing of precious metals extremely challenging. Process selection is most important in any precious metals project and is mainly driven by the grade, reserve and mineralogy of the target elements. Free-milling ores, such as Kupol in Russia, Hemlo in Canada, Grasburg in Indonesia, UG-2 in South Africa, Lac des Iles in Canada, and Noril’sk in Russia, can be processed using flotation or cyanidation with or without gravity. B2Gold Corp, a Canadian gold company, just started a number of new and under construction free-milling gold operations such as Fekola mill in Mali, Mastbati mine in Philippins and Otjikoto mine in Nambia. However, refractory ores (particularly gold ores), such as the Carlin and Goldstrike mines in the USA, Giant in Canada, Pueblo Viejo in Dominican Republic, Porgera and Lihire in PNG, Kittilla in Finland, Fairview in South Africa and Shuiyindong in China, must be processed using pre-oxidation prior to cyanide leaching. In some mildly refractory gold ores, such as Kumtor mine in Kyrgyzstan and KCGM in Australia, ultrafine grinding is required to liberate fine-grained gold particles. For some gold ores containing both free-milling and refractory components (such as Cripple Creek mine in Colorado, USA), two or more recovery processes may be required. The variability of grade, metal deportment, ore hardness and other parameters is one of the risks that encountered in development and operation of many precious metals projects. To minimize and reduce the technical risk caused by ore variability, geometallurgy and process mineralogy have been used by mining companies in the last two decades to measure and quantify the spatial variability of the deposits that are being developed. This paper presents an overview of fundamentals, methodologies and techniques applied in geometallurgy and process mineralogy, it highlights the importance of both disciplines in process selection and plant optimizat"

Jan 1, 2018

By Ajay K. Jha1

Drilling and Blasting are two important unit operations in the production cycle of a mine and a strong link exists between these two and other unit operations/subsystems like loading, transportation, and crushing. Under the present concept of ? Mine to Mill?, it is important to optimize the drilling and blasting operations by applying scientific approach to drilling and blasting using sophisticated instruments and new technologies, which depends heavily on Information technology (IT) to meet this imperative. Development of innovative models and software has lead to blast optimization process. Till date, the blast results are evaluated in terms of available empirical approaches like powder factor, which are too simple to exclude some key parameters or lack in providing reliability because of non-availability of user friendly IT enabled techniques. Although with the help of developed approaches, formulation of user-friendly software to assist the site engineers in effective post blast assessment has started but there is a dearth of holistic approach to design an optimum blast considering the techno-economic feasibility of the subsystems and the geo-mining conditions to achieve blast optimization. The science of IT enablement in drilling and blasting is capable to build innovative models for achieving blast performances which will be doped with productivity, economy and safety with due regard to environment. The present paper discusses the use of existing IT enablement in various mines of India citing the Indian scenario and the future requirements for achieving the techno-economics in overall mining operations.

Sep 1, 2012

By G. P. Wong

"In the Inco matte separation process, a slow-cooled converter matte is separated into three main discrete mineral phases: chalcocite (Cc), heazlewoodite (Hz) and a Cu-Ni-Fe alloy. After magnetic removal of the alloy, Cc and Hz are separated by flotation at pH>12 with diphenyl guanidine (DPG) as both collector and frother. High selectivity is achieved in rougher flotation. However, in later flotation stages such as in the middlings circuit, as oxidation takes place, Hz becomes highly floatable, resulting in a very poor separation between Cc and Hz.Starch and dextrin as Hz depressants were evaluated on the middlings circuit feed and showed no positive impact on Cc/Hz separation selectivity. Ethylene diamine tetra-acetic acid (EDTA) extraction showed the existence of abundant surface Cu and Ni ions. The use of triethylene triamine (TETA) or EDTA in flotation did not improve Cc/Hz separation selectivity. Microflotation tests were carried out on pure synthetic Cc and Hz minerals. It was found that Hz did not float in the presence of DPG. However, Hz conditioned with either copper sulfate solution or in contact with Cc floated readily in the presence of DPG. It is concluded that the major reason for Hz flotation in the middlings circuit is due to Cc oxidation releasing Cu ions that adsorb on the Hz surface making it reactive with DPG thus rendering the Hz floatable."

Jan 1, 2003

By Minna Päällysaho

For the first time, the idea of sustainable development was recognised at a high political level at the UN Conference on Environment and Development held in Rio de Janeiro in 1992 (UNEP, 1992). Then the governments of the world committed themselves to promote sustainable development in their national activities and international co-operation. In 2001, the European Council approved the EU Strategy for Sustainable Development (European commission, 2011). This complements and supports the EU?s so-called Lisbon Strategy (European council, 2000) on competitiveness. The revised Strategy for Sustainable Development was approved in June 2006. Recently sustainability has had an important role in policy and decision-making while the public awareness towards limits of the environment has been rising. However, the indicators of industrial sustainability satisfy primarily the needs of corporate management and global investors. The information is often broad and non-specific and might occasionally even give a false impression. Moreover, contradictions between environmental, economical and social aspects also point out the unreliability of existing sustainability indexes. Therefore, the current state of affairs serves the interests of neither the industry nor the policy makers. Current corporate sustainability indexes and indicator systems need to be assessed with scientific methods encompassing the identification of their strengths and weaknesses. This requires quantitative and qualitative assessment and synthesis of existing indexes and indicator systems, providing new data on the functionality of existing corporate sustainability indicators. Therefore, the assessment lays the foundation for the development of new, more balanced sustainability index. Our first aim in this multidisciplinary article is to analyse existing global sustainability indexes for process industry. Second, we will introduce a first version of a new sustainability index for process industry, which includes the environmental, social and economic impacts of the plant, as well as legislation aspects.

Sep 1, 2012

By M. M. Fan

In Florida?s phosphate industrial practice, the most favorable upper size limit of froth flotation is 1.18 mm which corresponds to particle weight of about 2.8 mg. Conventional froth flotation is not efficient in upgrading coarse particles (+0.425-1.18 mm). A limited number of studies have been devoted to understanding and improving coarse particle flotation. We have shown that the coarse particle flotation performance can be significantly improved by the presence of picobubbles generated by hydrodynamic cavitation. In this study, the size of picobubbles produced under certain hydrodynamic conditions was measured by a laser particle size analyzer. A size-by-size flotation performance analysis of coarse phosphate froth flotation in the presence of picobubbles is conducted in terms of flotation kinetics, selectivity and recovery. It was found that picobubbles doubled the flota-tion rate, increased the P2O5 recovery more significantly for +0.85-1.18 mm particles than +0.425- 0.6 mm and +0.60-0.85 mm particles. At a given acid insolubles (A.I.) rejection, the presence of picobubbles increased the P2O5 recovery by up to about 25%.

Jan 1, 2014

By Q. Huo

The alumina production might not continue when the sulfur content of bauxite was too high. In order to bring down the sulfur content in bauxite, we studied on the bauxite desulfurization by bacteria screened from the acid mine drainage at mines of high sulfur content. The screened bacteria were domesticated by the high sulfur content bauxite. The experiments of bauxite desulfurization were carried out under the conditions of 5% pulp density, temperature of 30?, rotate speed of 120rpm. Bacterial desulfurization for 30 days, the sulfur content of the bauxite was reduced from 5.73% to 1.55% and the desulfurization percent was 72.9%. The recovery percent of alumina was 94.3%. The study showed that it was feasible to bring down the sulfur content of bauxite by bioleaching and this technique might make full use of the low grade bauxite.

Jan 1, 2014

By Moris Fresko, Julia Sun, Charles C. Golembewski, Vytas Svalbonas

"A history of mill strain gaging at Metso is presented. The output of these strain-gaging programs is compared with calculated stress ranges from different finite element solutions. These comparisons expose the amount of approximation that exists in the analytical solutions, starting from geometry, and material properties, and ending with different forms of internal load models. The influence of strain gaging results on mill design and analysis practices is also discussed. While these instrumentation programs are valuable in identifying areas of high stress in mills, and locations of stress concentration factors, they are by no means extensive or comprehensive enough to verify general internal load models. The vast majority of the programs were aimed at getting additional data about potential failure points, rather than describing overall mill stress behavior. This is especially true since the more recent gaging programs have not included the difficult task of gaging the mill rotating structure interior. This paper tries to avoid the novice path of leaping to general conclusions on the basis of insufficient data."

Jan 1, 2014

By J. Leite

In a small-scale mining in Brazil?s northeast, scheelite were exploited since 1940?s using a traditional gravity concentration flowchart (composed by jigs and shacking tables) that operates with low efficient for fine particles. Tailing of this plant was submitted to chemical, mineralogical and size characterization. Results pointed 50% smaller than 74µm with a grade of 0.11% WO3. The particle?s size is an important operational variable to heighten recuperation by shacking tables. Tests using Falcon SB40 centrifuge concentrators and shacking table were realized, optimizing their operational variables. Based on the tests results a new flowchart was proposed for concentrating and tailings recovery.

Sep 1, 2012