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By R. Hejazi, Saghaeian. M., H. Abedini

Continuous vacuum belt filters mainly carry out an important duty in the solid-liquid separation processes such as iron ore concentrate dewatering. However as the particles become finer, the resistance to filtration and dewatering would increase and as the result cake moisture content tends to increase. So in recent decades, using additives in order to improve the filtration performance has been considered by many researchers. In the present study, the effect of several surfactants on the filtration rate and cake moisture content of Chadormalu iron ore concentrate (80% =40 micron) was investigated using a laboratory scale vacuum filter. The results of several tests indicated that a non-ionic surfactant (Lauryl Alcohol Ethoxylated, LAE) has the best performance on reducing the moisture content of the cake and reducing the cake formation time. The optimum dose of LAE was found to be 300 g/ton which reduced the concentrate cake moisture content from 13.76 to 11.28% (wet weight base). Some industrial filtration tests were performed in Chadormalu iron ore concentrate plant to prove the effectiveness of this surfactant. The surfactant is mixed with water and added to the concentrate slurry before distributing on the vacuum belt filter. The industrial and experimental results were almost similar, so that adding about 300 g/ton of LAE would reduce the final cake moisture content from 12.87 to 10.76%.

Jan 1, 2014

By Gülay Bulut, Ferihan Göktepe

Pyrite is the most abundant and widespread sulphide mineral and its flotation has been investigated by many researchers. It is well known that, pyrite is floatable under acidic conditions and recovery drops with increase in alkalinity due to changes in solubility of iron hydroxides on the pyrite surface. Most of the works also revealed out that pyrite displays variable behaviour in flotation circuits. This behaviour mainly related with origin and mineralogical composition of ore, liberation size, electrochemical behavior of minerals constituting ore, the trace and minor element content of the mineral, texture, application variables belonging to flotation circuits. In this study, copper activation effect was examined on different origin of pyrites. The experiments were performed with five high grade samples of pyrite from the different mining districts of Turkey. The pyrite samples were different from each other with respect to either their physical or chemical properties; they were different physical appearances and contained different associated minerals. In the micro-flotation tests, 1x10-4 mole/L copper sulphate and 1x10-4 potassium ethyl xanthate were used as flotation reagents. First of all pyrite samples were floated using only xanthate at different pH. Results showed that best floatation results obtained at acidic pH range for all pyrite samples. When copper ions were used to activate, all pyrite samples floated at neutral and basic pH values, too but depending on the samples, recovery and pH ranges were slightly changed.

Jan 1, 2014

By G. Dodbiba, T. Fujita, M. Kawata, S. Yamasaki, K. Mitsuhashi, J. Ponou, Y. Iwazaki, T. Atarashi

"The grade of copper ore and concentrate is recently decreasing and it will continues decrease further in the future. The effective liberation treatment for low grade copper ore and the removal of arsenic from copper concentrate is becoming even more important. In this work, the magnetic separation of copper concentrate by heat treatment and the flotation of low grade copper ore by microwave irradiation was studied. The heat treatment of copper minerals in the air atmosphere, the magnetization of most copper minerals increases and especially the magnetization of chalcopyrite shows the largest magnetization, after being heated at 500 oC. The wet HGMS of copper concentrate has been studied and the results have then been compared with the ones when calcined concentrate was used instead. The microwave treatment before ball milling increased the degree of liberation up to 100%, especially when compared with the case when only ball mill was applied to the as-received ore. The flotation of ground copper ore after microwave irradiation showed that the grade copper minerals such as chalcosite and bornite in froth part is much larger than that of tailing part.INTRODUCTION The copper has been used many kind of technological fields and will be more important for the future technology. The global copper production from mine is predicted as shown in Figure 1 (Northey, S. 2014). The copper production peak will be appeared in 2030 and the demand peaks in 2040. In the future the recycling of stocked copper and copper alloy will be necessary to satisfy the demand (Yoshimura, A. 2018). Changes in the grade of copper in copper concentrate, exported from several countries are shown in Figure 2. The copper grade in copper concentrate after mineral processing is gradually decreases every year and it is less than 30% nowadays. On the other hand, the copper ore grade change and prediction are shown in Figure 3. The grade of copper ore is also decreasing to less than 1% in 2010 (Northey, S. 2014). In the future the copper grade gradually decreases, reaching to less than 0.5% in 2080 and the energy to produce the copper metal will increase. The effective liberation treatment for low grade copper ore and the removal of arsenic from copper minerals become more important, nowadays. The microwave irradiation of copper ore for the liberation, energy etc. has been reported by several researchers (for example, Batchelor, A.R. 2017). The magnetization change of copper ore by heating has been reported to remove the arsenic (Sawada, M 2015). In this report, the magnetic separation of copper concentrate by heat treatment and the flotation of copper concentrate by microwave irradiation are discussed after the characteristics of secondary copper minerals are investigated by these treatments."

Jan 1, 2018

By R. Weyhe, B. Friedrich, H. Heegn

"Nickel-metal hydride batteries (Ni-MH) are storers of electrochemical energy, which have a higher specific storage capacity than lead or nickel-cadmium batteries. The demand for Nickel-metal hydride batteries is increasing rapidly since their market launch in the early 1990's. In 1999 the output of cells exceeded 80,000 tons per year (1 billion cells per year). Today there is no suitable and sustainable recycling process to recover nickel, cobalt and rare-earth metals. The discarded batteries are used in the steel industry as alloy material because they contain nickel. Cobalt and rare-earth metals are lost; they are non-recycleable.In a German governmental funded research project, IME Aachen, ACCUREC Mühlheim and UVR-FIA Freiberg are cooperating in processing as well as in creating a feasibility study. The target of this project is the development of a new recycling process for metal recovery from Ni-MH-batteries. The proposed process consists of a combination of mechanical, pyrometallurgical and hydrometallurgical processing steps.After shredding the steel shell, the various fractions of battery materials are carefully separated by mechanical processing. A hammer mill with one rotor with a perforated discharge grid of 20 mm opening, was found to be suitable for crushing the batteries to release the active mass of electrodes for metallurgical processing. The ground material is wet screened at a mesh size of 0.5 mm; thus a fine fraction is obtained with valuable components such as Ni, Co, and RE and an oversized fraction consisting of a mix of iron chips, electrodes grids, plastic chips, paper, and flocculent material of separators. The organic components are avoidable when there is a thermal step at the beginning of processing batteries.The separated fine fraction is smelted in an electric arc furnace. Any pyrometallurgical process relies on a suitable slag system. In this specific case, the process has to allow separation of nickel and cobalt as metal from the rare-earths almost quantitatively, collecting the rare-earths as well as impurities e.g. as oxides. The products are a nickel-cobalt alloy and a slag phase enriched with rare-earth oxides for further treatment to ‘mischmetal’."

Jan 1, 2003

By Tracy Shimmield, Philip Samar

"Metals have been mined as ores since pre-history but metal production has increased dramatically in modern times driven by expanding Global GDP. Metal ore mining produces large amounts of waste rock and mine tailings. Mine tailings are the wastes produced after extracting the desired metal from the ore. There are several ways of dealing with this waste, and Ritcey (2005) identifies the following possibilities, land-based storage, backfill to the mine, deep lake disposal and marine disposal. In Papua New Guinea (PNG), both Misima and Lihir Mines adopted the marine disposal option, releasing tailings through a submerged pipe onto the sea floor. This special case is referred to as Deep Sea Tailings Placement (DSTP) in which the tailings deposition is sufficiently deep as to be below the euphotic zone. The most important aspect of deep sea tailings placement is that the tailings are deposited at great depth where exchanges between the seabed and the surface layers are small. The first quantitative multidisciplinary study of tailings impact on the deep sea was carried out from 2006 to 2010 in Papua New Guinea. The physical, chemical and biological work carried out has placed PNG at the forefront of research into the assessment and management of deep-sea environmental impacts related to mining in PNG. The study has provided data which has led to a better understanding of the ecological and geochemical processes in deep water that accompany DSTP in PNG and provided baseline data on deep-sea ecosystems in a scientifically poorly known tropical ocean. Additionally, guidelines on best practice for DSTP have been developed Here we present geochemical data obtained from sediment samples from the marine environment surrounding Lihir and Misima Islands."

Jan 1, 2014

By D. Bastin, J. Frenay, J. Dassas

"The Luiswishi deposit belongs to the Cu-Co deposits of the Southern Group of the Katangian Copper Belt and is operated by a joint venture between EGMF (Entreprises Générales Malta Forrest) and Gecamines (Générale des Carrières et des Mines). The Cu-Co ore is beneficiated by the sulphidization process at the NCK (New Concentrator of Kipushi) at Kipushi.Sulphidization followed by flotation with sulphydryl collectors is a common practice for the treatment of oxidized base metals ores. This process is complex and its application at the industrial scale is quite sensitive. In Central Africa it is also a cost intensive treatment as the sulphidizing agent has to be imported. In order to improve the metallurgical performances and to optimise the economics of the process, a laboratory research program was carried out by the Laboratory of Metallurgy and Mineral Processing (MTM) of the University of Liège in close collaboration with EGMF and Gecamines. This program included the study of various flotation reagents as dispersing, depressing and activating agents.This paper presents the results obtained with the use of ammonium sulphate as activator of the sulphidized xanthate flotation. Although ammonium sulphate has been mentioned in the literature as a promoting agent of the sulphidized xanthate flotation of malachite, its effects on the flotation of cobalt oxides was not known.The testworks were carried out on various oxidized siliceous ore types from the Luiswishi deposit. A 1.7 l Agitair laboratory flotation cell was used. NaHS and potassium amylxanthate were respectively choosen as sulphidizer and collector. A mixture of gasoil and tall oil (90/10) was used as secondary collector. A multistage sulphidization was realised. Values of pH were followed during the different tests and an ion selective electrode Ag/Ag2S was used to control the Es potentiel evolution during the stepwise addition of the sulphidizer."

Jan 1, 2003

By Carlos Pereira, Fábio de São José, Francielle Nogueira

Votorantim Metals Corporation is one of the leader companies in the extraction of zinc in Brazil. One of its mines, located in the city of Vazante - MG, was composed by zinc silicate ores, but recent studies have indicated a change in mineralization type with arise of zinc sulphide’s ore bodies with disseminations of galena (PbS) and silver. The liberation size between sphalerite and galena in this ore occurs in very fine granulometry (approximately 18µm), fact that has negatively influenced into the flotation process. Aiming to reduce this problem, studies about the use of dispersing in the flotation process have started. Thus, this study investigated the action of different reagents dispersing on the stability of the suspensions. The tests were carried out with samples of mineral galena and sphalerite using four types of dispersing within two different dosages and two pH. The reagents tested were sodium hexametaphosphate, sodium silicate, carboxymethiylcellulose, and sodium polyacrylate. The results of the dispersion tests were analysed in relation to dispersion index. The tests with hexametaphosphate showed high dispersion for both galena and sphalerite. The sodium polyacrylate and arboxymethiylcellulose showed a high dispersion index for galena and a low index for sphalerite implying that reagent can be used in the concentration process of galena.

Jan 1, 2014

The energy dispersion X-ray fluorescence (EDXRF) analysis technique is a rapid and accurate method for describing sample?s element component and percentage composition. On the base of profound research for the national and international development and research condition, the author researched the EDXRF analyze technique and the EDXRF analyzer?s principle in depth, the difficulties and the key points for research and development of EDXRF analyzer; gave a scheme for re-search of bench EDXRF analyzer; researched some algorithms used in energy spectrum analysis; developed the energy spectrum analysis software based on the Visual C++ 6.0; together with the energy spectrum analysis software, the author designed and processed the structural of the bench XRF analyzer and integrated the import X-ray tube, thermoelectrically cooled Si-PIN photodiode X-ray detector and pulse amplitude analyzer as a model machine. The result shows: The model machine can be used in multi-element analysis at the same time for different types of dry mineral samples, with fast analysis speed, accurate model and high stability.

Jan 1, 2014

By Miguel Becerra, Daniel Jordán, Jorge Soto, Luis Torres

"Most SAG grinding operations currently use ball sizes between 5.5 and 6 inch maximum size. However, in most cases the use of this ball sizes hasn’t been justified by a phenomenological analysis of the real effect on the grinding process, but rather by trial and error. The analysis of the influence of ball sizes in SAG grinding hasn’t been developed in detail by considering the effect on process parameters inside the mill, grinding efficiency or internal classification. Historically a conventional grinding reference has been made on the empirical procedure developed by Azzaroni (1980). Further to Azzaroni’s methodology, Sepulveda (Sepúlveda, 2007) developed the SPEC methodology, incorporating the ball size effect on the grinding efficiency parameters using a population balance model included on Molycop tools spreadsheets.This paper demonstrates a detailed analysis at pilot scale of the ball size employed in SAG grinding and scaling that exists between the different levels. This analysis includes assessing the effect of balls sizes on parameters associated with grinding efficiency and its effect on the total fill level, product size distribution and specific energy consumption, among others. In a complementary way it develops a technical - economical evaluation from industrial data comparing two different ball sizes and its effect on the grinding process analysed integrally."

Jan 1, 2014

By Douglas Fuerstenau

"Comminution not only is the major energy cost in mineral processing but it also can limit the grade of ores that can economically be processed. Rittinger first postulated that the energy for comminution is proportional to the new surface produced. Because most of the strain energy needed to initiate and propagate cracks in particles cannot be recovered, researchers reported woefully low comminution efficiencies. Recognizing this, Schoenert proposed that the baseline for assessing comminution efficiency should be the mechanical energy needed to break single particles. After extensive single-particle studies, Schoenert turned to comminuting beds of particle in piston dies. Finding particle-bed comminution to be energy efficient, he had the brilliant conception of making the process continuous, namely his invention of the choke-fed high-pressure roll mill (HPGR). Practical comminution involves masses of particles, which can lead to energy efficiencies far less than that of single-particle breakage. A three-way classification of grinding modes in terms of the mobility of the particle mass provides the necessary insight into the low efficiency of different comminution machines: namely, single-particle breakage, confined particle-bed grinding (HPGR), and loose-bed grinding (ball mill). Examples are given for determining and comparing comminution efficiencies. The size distribution of comminuted products become self-similar, and a single parameter, the median size, can be used to quantify the extent of comminution. The reduction ratio, expressed in terms of the mean size of the feed and product, varies linearly with expended energy and the slope of such plots is a measure of the grindability of the mineral. This approach clearly gives the order of energy efficiency as single-particle > particle-bed > loose-bed comminution. HPGRs are more efficient at low reduction ratios but lose that advantage at higher reduction ratios. Extensive hybrid grinding experiments carried out with our instrumented ball mill and HPGR showed significant energy savings by first comminuting the material in the HPGR and followed by the ball mill. At Cerro Verde an industrial-scale hybrid HPGR/ball mill system is reported to have a 13 percent energy savings over a SAG mill/ball mill system."

Jan 1, 2014

By C. Dorfling, C. A. Snyders

South Africa has extensive mineral processing and extractive metallurgy capacity and infrastructure for metal production from natural resources. Decreasing ore grades, increasing labor costs, and more stringent legislation have made economic metal production from primary resources challenging. Opportunities exist for metal production from secondary resources such as mining wastes and end-of-life consumer goods. The objectives of this study were to evaluate the current status of metal production from secondary resources in South Africa and to identify potential opportunities for further development. Two main classes of secondary resources, namely mining waste and electronic waste, were considered. Primary metal producers are dominating metal production from mining wastes; several of the gold, platinum and chrome producers operate low risk and low cost tailings retreatment facilities that contribute significantly to their overall production. Further opportunities exist in, for example, the treatment of more than 450 estimated gold tailings dumps in Gauteng, as well as metal recovery from slags and furnace dust. The majority of companies involved with electronic waste recycling in South Africa focus on collecting and disassembling; only a few perform preliminary physical processing, with the recovered fractions then being sent overseas for metal recovery. Projections are that the rate of waste generation will increase significantly and that treatment will become critical to comply with more stringent environmental legislation. Projects related to process development, techno-economic evaluations and environmental impact studies for metal recovery from batteries, printed circuit boards, and fluorescent lamps are underway. South Africa is ideally positioned to further explore opportunities for synergistic relations between metal recyclers and primary metal producers. Processing of electronic waste for production of technology metals, for which limited natural resources exist in South Africa, would be a key enabler for local manufacturing industries and expansion of the value chain.

Jan 1, 2018

By Brian Lindner, Lidia Auret, Niel Knoblauch

In this paper, a fault detection and identification framework based on feature extraction and topology extraction methods is proposed, and evaluated on a simulated base metals refinery high pressure leaching process. Feature extraction methods included linear and kernel principal component analysis, while process topology information was extracted with linear cross-correlation, partial cross-correlation and transfer entropy. Connectivity maps were constructed to identify possible fault propagation paths to aid root cause analysis. The results indicate that process topology can enhance the fault identification capability of data-based process monitoring methods. The study of the considered base metals refinery pressure leaching process is ongoing, with future work including the creation of a fault library which would lead to further critical evaluation of the proposed fault detection and identification framework.

Jan 1, 2014

By G. Venkateswara Rao

The jigging of ferrous ore to produce higher-grade products has been practiced for many decades. This is due to easy separation, a beneficial trade- off between operating cost and reduced yield relative to Dense Media Separation (DMS). Jigging becomes prominent for beneficiation of iron ores in the coarser size range. At present drive is towards the use of under bed air pulsed jigs for the beneficiation of ferrous ores. The main advantage is that the under bed air pulsed jigs are capable of generating the large pulse of amplitudes required to fluidize a deep bed of heavy ores particularly lump iron ore up to 40mm size. The major jig parameters effecting the jigging operation are bed height, shape of the pulse, residence time, operating pressure, valve cycle time and water flow rate. With the pulse shape set correctly for optimum stratification rate, even it is still necessary to provide enough residence time, to ensure the difficult material will take time to migrate to the expected layer in the bed. In order to find the Jig Stratification Index (JIS) parameters like bed height, operating pressure, water flow rate, cycle valve time and shape of the pulse were optimized first by conducting various tests. Typical Iron ore samples from Odisha (both lump and fines) were subjected to stratification studies at residence time of 1, 5 and 15 minutes. Jig Stratification Index (JSI) for both lump (0.30) and fines (0.20) were determined by using APIC Jig. The maximum possible JSI was calculated by using heavy liquid separation test (0.42 for lump and 0.24 for fines). It is found that the jig bed JSI is less than the Heavy liquid JSI for both lump and fines. The ratio of Jig bed JSI to the heavy liquid JSI is 0.83 for lump and 0.71 for fines. The JSI and ratio of Jig bed JSI to Heavy liquid JSI are low for fines due to fluid turbulences causing some degree of remixing in the jig bed. The fluid turbulences are more for fines than lump, hence jigging of fines is difficult and challenging. Keywords: sub grade iron ore, gravity separation, jigging, apic jig, stratification, residence time, jig stratification index

Sep 1, 2012

By H. J. Schulze

From a colloidal science point of view (Schulze 1984, Nguyen & Schulze, 2004) five micro-processes are responsible for successful particle-bubble formation: the approaching of the particle to the liquid-air interface, the thinning and rupture of the intervening liquid film, the expansion of the three phase contact perimeter, the generation of sufficient large capillary force to stabilise the aggregates and the transport process of particles into and within the froth layer. Flotation reagents influence mainly the thinning and rupture of the intervening liquid film between particles and air bubbles, the expansion of the three phase contact after the rupture of the liquid film and the stability of the aggregates against external destruction forces in the flow field. But it exist also a non-negligible influence on the approaching of particles to the bubble surface during the encounter process and on their passing over into the froth layer and the froth stability.

Jan 1, 2003

By E. Szelag

The adsorption and stabilization of mineral dispersed systems by using Pluronic copolymers with different molecular weights and EO content has been studied. The role of sequential adsorption of EO-PO copolymers and cationic surfactant (CTAB) on the carbonate particle properties and in determining the stability of their suspension was studied with particular attention to the conformation of the polymer at the solid-liquid interface. The purpose of this work was to investigate the flocculation phenomena, influence of polymer molecular size on stability of suspensions of magnesite and dolomite and the effect of addition mode of polymer and surfactant. The suspension stability measurements and the determination of sedimentation speed were carried out using an optical analyser (Turbiscan). In most of investigated cases, the biggest floccs and the fastest sedimentation were found for low concentrations of copolymers.

Jan 1, 2014

By A. M. Ozbayoglu

Gross calorific value (GCV) of coals was estimated using artificial neural networks, linear and non-linear regression techniques. Proximate and ultimate analysis results were collected for 187 different coal samples. Different input data sets were compared, such as both proximate and ultimate analysis data, and only proximate analysis data and only ultimate analysis data. It was observed that the best results were obtained when both proximate analysis and ultimate analysis results were used for estimating the gross calorific value. When the performance of artificial neural networks and regression analysis techniques were compared, it was observed that both artificial neural networks and regression techniques were promisingly accurate in estimating gross calorific values. In general, most of the models estimated the gross calorific value within ±3% of the expected value.

Sep 1, 2012

By A. N. Zagorodnyaya

The results of research on recovery of ammonium perrhenate from by-products of lead production are presented in the article. For the first time in the world, rhenium marketable products were produced on lead plant of Kazakhstan. Distribution of rhenium in lead production has been studied. During oxidative agglomeration of lead charge, 67.43% rhenium is sublimated and at that, 67.27% rhenium is trapped by the dusts of a system of gas purification, out of them 6.21% is transferred into different solutions, 1.89% into slime and only 0.09% into exhaust. During agglomerate smelting, up to 72% of its rhenium is sublimated and condensed in the dusts also. At leaching stage of sulphate product under dusts processing by the method of sulphatization, 15% of its content in the dusts is transferred into solution. The sorption method on the ionite ?N-21 has been proposed for recovery of rhenium from the solutions of sulphatization. At the same time, rhenium recovery from the dusts into commodity was 13%. The method of direct hydrometallurgy - leaching the dusts by solutions of sulphuric acid under presence of manganous concentrates, has been proposed as alternative method of recovery. This method has allowed increasing recovery of rhenium and other metals from the dusts into solution up to 90%~95%. Rhenium solvent extraction by ??? has been proposed for recovery of rhenium from the leaching solutions. At that, extraction of rhenium into marketable product from the dusts is above 75%.

Jan 1, 2014

By Yagmur Sirinyurt, Ayhan Ali Sirkeci, Gülay Bulut, Mustafa Özer, Tuncer Acar

"The basic requirement of glass industry for the silica sand is at least 99% SiO2 content. On the other hand, coloring impurities such as Fe and Ti, must be removed. Flotation is the most widely used method for the purification of silica sands from impurities. In this study experimental studies were carried out to reduce Fe content of Mersin (Turkey) district silica sands by flotation. Silica sand sample with a d80 particle size of 1.85 mm was reduced below 0.5 mm in size. Then the size fraction -0.5 +0.106 mm was subjected to flotation tests. In flotation tests, sulfonate-type R801-R825, fatty acid based DER NA 7 (Produced by a Turkish company) and HA110-HA150 a blend of various chemicals produced by Mersin Cam-Is Mining Company (producer of glass raw materials) were used as collectors. Flotation tests showed that sulfonate type R801-R825 collectors provided much better results in acidic medium (pH: 3). The optimum pH value for DER NA, HA150 and HA110 collectors was found to be 7. It was observed that the addition of collector at once caused an increase in the amount of floated product that resulted in a loss of silica to the tailings. In the case of multistage addition of the collector much better selectivity was achieved. As a result of flotation tests conducted under best conditions, a concentrate assaying 0.046% Fe was obtained with a weight percentage of 93.4 when DER NA 7 was used as a collector. In the case of R801-R825 a concentrate was produced with 0.058% Fe content with a yield of 98.4%. On the use of HA150-HA110 the concentrate was produced with 96% weight recovery and 0.052% Fe content."

Jan 1, 2014

By Polezhaev S. Yu, I. V. Ukraintsev, Boduen A. Ya, Saburbayeva L. Yu

"Comparison studies of different technologies are performed when selecting optimum option for gold ore and concentrate processing. Methods of ultrafine grinding, oxidizing roasting, bacterial leaching and pressure oxidation are used to extract gold from refractory ores and concentrates. Refractory gold flotation concentrate produced from pyrite-arsenopyrite ores of Bestobe deposit is a case study in this paper. The results of the experimental tests of the direct leaching of flotation concentrate and pre-oxidation products using different methods (oxidizing roasting cinder, pressure oxidation and bacterial leaching cakes) are the following: - cyanidation of original flotation concentrate provides recovery of Au at 46.6 %; - oxidizing roasting increases gold recovery from 46.6 % to 85 %; - BIOX increases gold recovery up to 86 %; - preliminary pressure oxidation of flotation concentrate ensures steadily high Au extraction in the follow-up cyanidation at 94.9-96.5 %. Pressure oxidation and bio-oxidation has changed dramatically the strategy of refractory gold ore processing. These solutions provided for development of ore deposits that considered earlier non-commercial. However, refractory ore processing has a complex character in terms of developing process flowsheet and requires large amount of studies to be performed for each new project. Gold extraction is the basic but not the only criteria to technology selection for gold ore and concentrate processing. Opex and capex, ore reserves, regional geography, developed infrastructure and skill personnel should be considered. Process studies and feasibility study of the developed technology shall be provided for each specific gold ore deposit. INTRODUCTION Due to changes in available feedstock and depletion of easy-to-process ores, refractory ores containing finely disseminated gold and silver in sulphides (primarily, in pyrites and arsenopyrites) are more and more involved into processing. Experts say that such ores amount above 40 % of the world’s gold reserves. Conventional technologies of gold extraction from refractory ores include flotation, roasting and cinder cyanidation (Fraser etal., 1991). However, today’s best available practice for refractory gold ore processing are bacterial (BIOX) and pressure (POX) oxidation."

Jan 1, 2018

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