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By S. L. Zheng

The compound material of Nano-TiO2 Supported on the diatomite was prepared by the hydrolytic method with purified diatomite and TiCl4. The compound material was characterized by SEM, XRD, TEM, EDX, XPS, and the application test of the compound material was studied. The characterization test results showed that the Nano-TiO2 was coated on the surface of diatomite, the crystal of TiO2 is anatase, and the average crystal size is 12 nm. The pore diameter was reduced, but pore volume and surface area of the compound material are increased after Nano-TiO2 Supported on the diatomite. The application test results for treating coking waste water and formaldehyde gas show that the compound material of Nano-TiO2 / diatomite has adsorption and photo-catalytic function and strong degradation performance for phenol and formaldehyde.

Jan 1, 2014

By Gus Van Weert, Samuel A. Bolorunduro, David B. Dreisinger

"Silver is currently lost as jarosite during the pressure oxidation of sulphides and cyanidation of the residues yields 5-10% of silver. Efforts to recover silver from complex sulphides, which contain economic fractions of silver require an understanding of the behaviour of acanthite during pressure oxidation. However, previous studies of acanthite (Ag2S) reaction have been complicated by the formation of argento-jarosite and uncertainties arise on the interpretation of the results.In this work, the acid pressure oxidation of high-grade natural silver sulphide mineral (acanthite) was carried out at 110-150°C and under the conditions similar to that of pressure oxidation of complex sulphide. The predominant product of reaction is elemental sulphur. The rate of reaction increases with increasing temperature and with the presence of ferric ions. The kinetics is controlled by chemical reaction with activation energy of 72.6 kJ/mol. The rate of reaction decreases with the presence of silver sulphate in the initial slurry. The proposed overall reaction is close to: []"

Jan 1, 2003

By Venkataramana Runkana, Aditya Pareek, Vishnu Masampally, Nagaravi Kumar Varma Nadimpalli

"Recovery and grade of the ore produced are two important metrics, which define the profitability of a mineral processing plant. Achieving high grade and high recovery at the same time in a mineral processing plant is difficult due to conflicting nature of the two objectives. To explore the operability limits of the plant operations and find the set of operating conditions that can help achieve the best possible recovery and grade, there is a need to solve a multi-objective optimization (MOO) problem. Past research focused on building a plant-wide simulation model or on optimization of individual units or a part of a mineral processing plant like grinding circuit, crushing circuit, etc. However, it is necessary to consider optimization of the complete plant in order to optimize the plant performance. Here, we have formulated the mineral processing plant performance optimization as a MOO problem. We have applied machine-learning algorithms such as random forest to build models to predict the recovery and grade of the ore. A non-dominated sorting-based multi-objective evolutionary algorithm called NSGA-II (Non-dominated Sorting Genetic Algorithm II) was employed to solve the MOO problem. Since the number of parameters that influence recovery and grade are quite large, we have applied machine-learning algorithms for feature selection or identification of key process variables. Pareto optimal conditions were determined for manipulated variables like grinding mill throughput, speed ratio at SAG mill, speed of centrifugal pump, water addition at different locations etc. The results obtained are useful in identifying the operability of a mineral processing plant to achieve the optimum grade and recovery for a given feed grade and the processing circuit. INTRODUCTION Copper is majorly mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits. Among all the available ores, sulfides are the most commercial ores, especially chalcopyrite (Greenwood and Alan, 1997). Copper grade in these ores generally lies between 0.4 to 1.0%. In order to perform smelting operation, the grade of copper has to be improved to around 30% (Biswas et al. 2013). This targeted copper grade is achieved through two stages of mineral processing. Firstly, the copper in the ore has to be liberated by crushing the mineral rock. Secondly, the liberated copper in the crushed ore is then physically separated from other minerals like nickel by froth flotation techniques."

Jan 1, 2018

By Z. G. Guan

The tungsten ore in Xingluokeng belongs to a symbiotic deposit containing granite and fine vein-type wolframite and scheelite. The tungsten (WO3wolframite) accounts for only 0.233% of the raw ore, 49.60% of the , 49.60% of the scheelite and 0.8% of the tungstite. The dissemination size of the tungsten ore is extremely uneven, with 0.02~1.28 mm for scheelite and 0.01~1.28 mm for wolframite. The dissemination size of scheelite is coarser than that of wolframite. The size of 83% of scheelite and 60% of wolframite is greater than 0.04 mm. The composition of minerals in the ore is quite complex. The major metallic minerals include wolframite, scheelite and pyrite, which are followed by molybdenite, chalcopyrite, arsenopyrite, limonite, magnetite, hematite and siderite. The major gangue minerals include quartz, feldspar, muscovite, biotite and sericite, which are followed by chlorite, fluorite, apatite, dolomite, etc. According to the dissemination features and liberation degree of the tungsten minerals, the technology flowsheet of gravity concentration for coarse particles and flotation for fine particles to re-cover the low-grade and fine vein-type tungsten minerals is adopted, and -0.7 mm is selected as the processing size. The closed-circuit grinding procedure, with the combination of the rod mill and high-frequency vibration screen, is adopted. The grinding product is classified into three products of -0.7 +0.2 mm, -0.2 +0.04 mm and -0.04 mm. The gravity separation is adopted for the former two to recover tungsten minerals and the flotation is adopted for the last one. Under the condition that the raw ore contains 0.23% WO3, some technology indexes of beneficiation have been achieved. The gravity tungsten concentrate contains 63.54% WO3 with the recovery 70.11%. The slime flotation tungsten concentrate contains 35.22% WO3 with the recovery 10.48%. The composite tungsten concentrate contains 57.53% WO3 with the recovery 80.59%. Thus, the tungsten minerals are re-covered effectively.

Jan 1, 2014

By M. Etelapaa

A new approach to controlling the process of selective flotation of sulphide minerals from pyrite in a lime environment is covered in the presentation. Advantages of process control based on the electrochemical potential of slurry controlled by ?? ? electrode are proved and compared to conventional methods of ?? ? metering and conductometry. Keywords: flotation, electrochemical potential, automation dosing system, neural network

Sep 1, 2012

By E. Lee

With the growing environmental concern, as well as the increasing concern for sustainability of natural resources, the need of improving the performance and efficiency of today?s crushers is be-coming increasingly important. However, the development of existing crushers requires an extended basic knowledge about the crushing process itself. The aim of the present study is therefore to find the theoretically optimal way of crushing compressively under given circumstances. In the present paper, optimizations have been performed with the purposes of maximizing product yield and minimizing energy consumption. Performed on an ideal crushing stage free from physical limitations, the optimization results have been obtained in terms of number of compressions and their corresponding compression ratios. Complementing earlier results on interparticle breakage (Hulthén et al., 2006), presented here are thus the results from corresponding optimizations with single particle breakage and interparticle breakage. It is concluded that modern crushers are not working optimally in any of the studied aspects for gneiss. In fact, optimizations indicate that a lowering of the compression ratio, as well as a shortening of the crushing sequence, are theoretically favourable. The outcome of this study is therefore highly promising as to giving new ideas and suggestions of improvements in existing crushers, and can even result in redesign of compression crushers.

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 A. Makavetskas

"The purpose of the research is to study the mineralogical features of the structure of the wall accretion formed during melting on the working surface of the walls of metallurgical aggregates and adversely affect the stability of the lining of blast furnaces (BF). We presented the results of studies of the material composition of lining and wall accretion of the furnaces of blast furnaces of the metallurgical plant specializing in the smelting of ferromanganese, nodular and pig iron. It is established that the garnissage is an aggregate of layered texture, formed as a result of the crystallization of slag and metallic melts. Refractory calcium and magnesium silicates and aluminosilicates (minerals of the melilite group, leicite, olivine group minerals) and amorphous glassy oxide solid solutions of variable composition crystallize from the slag melts in the upper part of the hearth. In the slag matrix, inclusions of carbon (amorphous and graphite) and products of crystallization of metallic melts of alpha-iron, iron carbides and / or manganese are observed. Evidence of carbon evolution (in the form of graphite) is precisely in the crystallization of metal melts, there are significant differences in the structure of carbon in coke and in the garnissage. The conducted studies confirm that it is impossible to obtain reliable information on the material composition of new formations in the blast-furnace process without using a complex of modern methods of technological mineralogy.INTRODUCTION The formation of the wall accretion (garnissage) - a solid protective layer as a result of smelting products crystallization on the inner (working) surface of the liner. This is due to the design of blast furnaces with a high-efficiency heat sink using copper coolers and the use of carbon blocks with high thermal conductivity in the lining. The objective of the study was research of the material composition of the lining and wall accretion of the blast furnace hearth of one metallurgical plant that specialized in smelting ferromanganese, nodular and pig iron, to assess the effect of new formations for stability of the lining of blast furnaces (BF)."

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 F. M. Zafar Kaifi

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

Jan 1, 2014

Poor floatability of fine particles is known to be the main cause of the low recovery of ilmenite in Panzhihua, which is the largest titanium mine of China. To get an optimum ilmenite recovery, selective flocculation, and flotation of fine ilmenite was investigated through flotation tests, particle size analysis, zeta potential tests and scanning electron microscopy. The results indicate that carboxymethyl cellulose (CMC) shows flocculation effect for both ilmenite and titanaugite without selectivity, while selective flocculation could be realized by the combination of water glass and CMC. It is because that competitive adsorption would take place on these two kinds of mineral when water glass and CMC are used together. On the surface of ilmenite, the adsorption ability of CMC is stronger than that of water glass, so that CMC can absorb to the same extent irrespective of the presence of a pre-adsorbed layer of water glass and ilmenite particles is flocculated by CMC. The same cannot be said of the titanaugite phase as water glass strongly adsorbs onto the titanaugite, and the adsorption of CMC is hindered. Therefore, the titanaugite particles keep dispersion. Furthermore, the flotation of fine ilmenite particles is feasible as the ilmenite floccules could react with sodium oleate. In the flotation separation of Panzhihua ilmenite ore, the recovery of TiO2 increased from 52.63% to 68.28% by selective flotation. Keywords: ilmenite, flotation, selective flocculation, adsorption

Sep 1, 2012

By C. Y. Sun

China is a country with abundant resources of tungsten, taking one of the world?s top-positions regarding both the total reserve and the amount of industrial production. China?s tungsten resources occur mostly in multi-metallic deposits rather than in single-metallic deposits. China?s multi-metallic tungsten ores have the characteristics of coexistence with other valuable components such as molybdenum, bismuth, copper, sulfur and fluorite. These ores are usually low in grade and difficult to process. The technological challenge in mineral processing lies in separation of multi-metallic components in these complex ores and a comprehensive utilization of natural resource. Several cases of industrial practice of processing China?s typical multi-metallic tungsten ores are presented.

Jan 1, 2014

By Swati Mohanty

Spiral concentrator, which works on the principle of gravity separation, is widely used in the mineral industries for separation of solid particles based on the size and density. In the present study, CFD simulation of the flow profile on a laboratory scale spiral concentrator of height 2.29 m, pitch 0.435 m and width 0.17m was carried out. A single computational domain covering the entire spiral was considered. Volume-of-Fluid algorithm was used to track the interface and predict the flow profile. In the present study the Donor-Acceptor method was used for the calculation of volume fraction in the cell. Simulation results show that the velocity increases as the water flows down due to the convective force and gravitational force, but the viscous force acting in the opposite direction retards the flow. Thus the maximum velocity is attained at turn three at which the viscous force overpowers the other forces and further down the velocity decreases. Measured water depths along the radius of the spiral at various heights were compared with simulated depths, which were in good agreement. The simulated liquid phase velocity profile was used to carry out preliminary studies on the flow profile of solid particles of size 500 micron and densities 2600kg/m3 and 5100kg/m3, based on the Lagrangian model taking into consideration fluid-particle interaction.

Sep 1, 2012

By Jun Xiao, Jianwen Yang, Yanhong Dong, Daixiong Chen

"MANGOTE Surface oxidizied mine is a gold-bearing deposit in Congo's Mai-Ndombe Province. In the past decades, the ore has been exploited in a crude way by local farmers, which directly causes the severe processing difficulty and lack of economy of cyanide leaching. Hunan Research Institute for Non-ferrous metals (HRIM) is currently investigating options to recover gold through understanding the mineralogical characteristics of MANGOTE surface oxidized ore. Chemical analysis , X-ray diffraction(XRD) and Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN ) were conducted on samples from mine site. The bulk analysis results showed that gold separation of gold from gangue minerals was feasible after grinding the ore samples to 86.53% -74µm and adjusting the pulp specific weight at 100g/L, and gravity separation was conducted with using spiral chute after grading of fine particles. The research results highlight relationship between mineralogical characteristics of abandoned ore and economy of comprehensive utilization that might be directive experience to similar cases. INTRODUCTION The occurrence state of gold in natural gold minerals determines the basic recovery and recovery effect of gold(Komnitsas, C., & Pooley, F. D. 1989). The occurrence of gold in the ore refers to the form of gold in the ore.Generally the existing state of gold can be divided into four major categories according to the viewpoint of the dispersion system: independent minerals and gold, a coarse dispersed system;colloidal gold, a colloidal dispersion; solid solution gold, is atomic ion dispersion; adsorptive gold, according to the adsorbed particle is the micelle or ion, respectively is a colloidal dispersion or ion dispersion(Mao, S. D., & Yang, R. S. 2009; Liu, J. J. et al. 2007; Horisberger, M., & Rosset, J. 1977; Li, Y., & Audétat, A. 2013).With the increasing technology of comprehensive utilization of resources,varied plants can now process different gold ores with various occurrence states(Neesse, T. 2014; 7. Ogundare. et al.2014)."

Jan 1, 2018

"The global demand for the copper metal is continuously increasing however, the high-grade copper ore deposits are constantly depleting. As a result, ore bodies with complex mineralogy characteristics and rich in arsenic-copper bearing minerals are increasingly processed. Arsenic-copper sulphides such as enargite can represent a significant amount of arsenic in concentrate, which causes high financial penalties by smelters. On the other hand, arsenic (As) is a highly toxic inorganic pollutant, which causes human health and environmental problems. Recent research studies have demonstrated promising results showing the possibility of separating arsenic-copper sulphides from copper sulphides using controlled pulp potential (Eh) flotation at laboratory scale. However, the selective removal of arsenic-copper minerals in real ore systems is not well understood. Two ore samples were selected from the Tampakan copper-gold deposit located in the Philippines named the HAS (high arsenic sample) and the LAS (low arsenic sample) samples and the mineralogical analyses were performed on both samples. The floatability of enargite in a batch flotation system under controlled pulp potential conditions was investigated for the HAS and the LAS samples. It was observed that it is possible to selectively separate enargite from other copper minerals after reducing the pulp potential to about -200 mV SHE at pH 11 in the LAS sample. However, no separation between enargite and other copper minerals was observed at a reducing potential for the HAS sample. Mineralogical analyses and surface chemistry studies were undertaken for both samples to find out the reasons for different observations. This study has an important implication in sulphide flotation to achieve sustainable development in the utilisation of arsenic-copper mineral resources. INTRODUCTIONAs the demand for copper is increasing, the extraction and development of resources including complex deposits is becoming necessary. These complex deposits often have issues such as: lower grade ores, floatable non-sulphide gangue, very fine-grained ore and therefore poor liberation and significant regrinding, mixed copper mineralogy, complicated galvanic interactions, economic levels of gold and silver, and high levels of impurities such as arsenic. There is currently no established methodology for separating arsenic-bearing copper minerals from other copper sulphide minerals by flotation. The possibility of separating arsenic-copper sulphides from other copper minerals by controlling the potential of the flotation pulp has been shown in previous studies. However most of these studies were conducted on single mineral systems and the selective removal of arsenic-copper minerals in complex ore systems is not well understood. The flotation behaviour of arsenic-bearing minerals within complex ores differs significantly from that of pure mineral systems due to the effects of mineralogical composition, the degree of liberation, and the surface oxidation. The understanding and manipulation of these effects can lead to improvements in the selective flotation recovery of arsenic-bearing species from complex ore systems."

Jan 1, 2018

By S. Kelebek, A. Khan, J. Caceres, Beckett. D.

"Pyrrhotite in nickel-copper sulphide ores is nickeliferrous and intimately associated with pentlandite. Due to its low nickel content, pyrrhotite rejection is an important step in processing of these ores. In our laboratory, various reagents were investigated for their effect on pyrrhotite depression. Among these, a combined use of triethylenetetramine and sodium metabisulphite was found highly promising.The work described in this paper has two parts. The firs part is a summary of results obtained on process samples from the pyrrhotite rejection circuit at Falconbridge’s Strathcona Mill. The second part involves simulation of the circuit performance based on the reagent conditions used in the experimental work and the concept of split factors.Two sets of reagent conditions were evaluated. The first one involved baseline conditions, simulating the current reagent performance. The second one simulated the impact these new reagents can have on the circuit performance.The simulation results obtained under baseline conditions indicated a good agreement with the current circuit performance. The simulation results suggest that at practically the same pentlandite recovery and tailing grades, the circuit concentrate nickel grade can be doubled through effective pyrrhotite rejection by these new reagents."

Jan 1, 2003

By T. Wajima

"A novel carbonaceous immobilizing agent for heavy metal contaminated soil was prepared from rice straw using sulfur immersion and pyrolysis, and the lead immobilization in artificial contaminated soils using sulfur-impregnated carbonaceous material was estimated. The rice straws were cut to 1 cm pieces, and then immersed in 0.1 - 1 M K2S solution for 0 - 24 h to prepare sulfur-immersed materials. The immersed-materials were heated at 400 oC for 1 h in nitrogen gas to produce the sulfur-impregnated carbonaceous material by pyrolysis. The abilities of the product to immobilize lead from aqueous solution were examined to obtain the product with high lead immobilization ability. With increasing K2S concentration, the immobilization ability of the product for lead gradually increases and then above 0.5 M K2S those are almost constant, while 15 min is sufficient for the immersed time to obtain the product with high lead immobilization ability. The product prepared from material immersed in more than 0.5 M K2S solution for less than 15 min has a maximum immobilization ability for lead ion. The lead immobilization using the sulfur-impregnated product is sustainable due to the formation of leadhillite [Pb4SO4(CO3)2(OH)2] and anglesite [PbSO4]. The product can immobilize lead ion in various artificial lead contaminated soils. By mixing artificial lead contaminated soil with the sulfur-impregnated product, the eluted solution became neutral, and the eluted concentrations of lead ion dropped below the Japanese elution standard for soil.INTRODUCTION Soil contamination with heavy metals is a worldwide problem. Accumulation of heavy metals in soils affect soil ecology, agricultural productivity, quality of agricultural products, water resources, and serious health problems for human and animal (Raicevic, et al., 2005). In the United States, for example, approximately 63 % of the sites on the National Priority List (NPL) for the treatment of contaminated soils are contaminated by metals, and lead is the most common metal, found at 15 % of the sites. In Japan, according to a report by the Ministry of Environment, 43 % of the contaminated sites that exceed the environmental quality standards are contaminated by lead compounds. Soil contamination by lead compounds is also prevalent in other developed and developing countries where lead compounds are used extensively in industrial activities without careful contamination management. Lead is a ubiquitous heavy metal pollutant in soils due to their use widely. The primary sources of Pb contamination include industrial activities such as mining, smelting of metals, and the use of Pb-containing products such as paints, lead-acid batteries, bullets, gasoline and pesticides (Cao, et al., 2009). It can damage human nervous (especially children) and reproductive systems (ATSDR, 2007). The high concentration of Pb in the soil poses risks to human and animal health by the leaching of metals from the soil into water and the consumption of edible plants growth in the contaminated soil. Therefore, proper remediation is necessary to reduce metal availability in soil for protecting human health."

Jan 1, 2018

By D. Johann, E. Zanetti, I. A. S. Brum, P. M. Zancan, A. F. Castro

"This study was done from a sample of coal mined at the Vale-Mozambique mine, located in Moatize district, Tete Province. The aim of this work is to analyze the reagent system in the flotation of coal fines belonging to the Upper Chipanga layer (UC). Among coal processing methods, flotation stands out as one of the most important for the concentration of this material, in particular in the treatment of fine particles. The total feed of the Vale-Mozambique processing plant is 8,000 tph of coal, where 10% of this feed corresponds to the fine fraction that feeds the flotation circuit. The material used in this study had a particle size of 96% smaller than 0.25 mm. The reagents used in the flotation tests were betacol and diesel oil as hydrophobizing agents and MIBC as frother. The range of betacol concentrations in the first test phase was 200 g/t to 500 g/t, and in the second phase 200g /t to 500g /t while diesel oil and MIBC were kept constant at 300 g/t. The immediate analysis followed the Brazilian standards NBR 8289, NBR 8293, NBR 8290; and NBR 8299. The results showed that it is possible, from a feed with ash content around 22.84%, to obtain products with levels below of 10% ash, with a mass recovery around 50%. The recovery of carbonaceous matter was also evaluated and presented positive results. Complementing this study, the effect of H2O recovery was evaluated and it was observed that for the concentrations of betacol the recoveries ranged from 6 to 9%, and for diesel oil plus MIBC were 4 to 7%.INTRODUCTION Considering the increase in population and energy consumption as humanity has been living along the last decades and the consequent demand for non-renewable natural resources, it is clear the challenge of the mineral industry in the search for new technologies and improvement of the existing ones. This challenge is justified by the need for better industrial results and to meet the market specifications, taking into account the reduction of deposits with higher contents and the need for beneficiation of more complex ores, lower levels and lower release granulometry. Usually in these situations, processes already well-established as the gravimetric (Sampaio and Tavares, 2005) have not good results."

Jan 1, 2018

The molybdenum ores currently utilized in China are mostly molybdenum sulfide ores whereas oxidized molybdenum ores, being finely disseminated and difficult to process, have not been exploited and utilized effectively. In this article the beneficiation process of a molybdenum ore occurred in an oxidized ore zone was investigated in order to provide a new way for the development and utilization of the oxidized molybdenum ores in China. The molybdenum mineral in the ore was mainly wulfenite and the associated minerals included barite, limonite, quartz and small amount of cerusite. Limonite in the ore occurred in a crust and honeycomb-like colloidal state and composed the framework for the formation of the other minerals in the ore, which filled the pores in the framework. Wulfenite was mainly fine-grained and occurred in the fine porous crust and honeycomb-like framework. The finely disseminated ore structure made the separation and recovery of the molybdenum mineral in the ore very difficult. On the basis of the mineralogical study of the ore, experiments were conducted to compare the various mineral processing methods for the beneficiation of the ore, including single gravity concentration, single magnetic separation, single flotation, and a combination of high intensity magnetic separation and gravity concentration. The results indicated that with single gravity concentration a molybdenum concentrate containing 5.85 % Mo with a yield of 11.76 % and a Mo recovery of 43.5 % was produced. With single high intensity magnetic separation it was very hard to obtain a molybdenum concentrate product. With single flotation process a molybdenum concentrate containing 7.06 % Mo with a yield of 15.14 % and a Mo recovery of 62.63 % was produced. With a combination of high intensity magnetic separation and gravity concentration a molybdenum concentrate containing 6.46 % Mo with a yield of 11.81 % and a Mo recovery of 42.11 % was produced. In conclusion, compared to the other methods the flotation process can produce more reasonable technological and economical results and is the best process for the exploitation and utilization of the finely disseminated oxidized molybdenum ore.

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