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By V. E. Dementyev

This paper presents a brief overview of some IRGIREDMET advances in gold hydrometallurgy. Original impulse-percolation technology and equipment for intensive cyanidation of gravity concentrates have been developed and introduced into industrial practice by IRGIREDMET since 1980s (RF Patents N1593250). The process is based on leaching using special hydrodynamic and reagent conditions providing high dissolution rate for coarse gold particles. Gold and silver are precipitated from pregnant solution by cementation or electrowinning. There was also proposed an im-proved cementation method using zinc in a contact with electrically conductive material. The units including closed water recirculation, tails detoxification and semi-dry tails IRGIREDMET is well experienced in gold adsorption technology using ion exchange resins and activated carbons. The comparison of CIL and RIL processes were done for a number of gold mines, for example for Sukhoi Log gold deposit. The properties of prospective foreign and domestic ad-sorbents including strong-base, bi-functional and weak-base resins as well as activated carbons were studied. The Institute has developed some adsorption/elution technologies and equipment, such as a two stage RIP adsorption technology for gold/silver ores, an improved technology for gold elution from loaded resin and carbon, electrowinning cells for gold recovery from RIP and CIP eluates etc. Large scale ?Resin In Pulp? tests using weak-base resin were finalized and process design criteria were developed. Gold plant design is on progress at the moment. Improved technology for carbonaceous (preg-robbing) gold ores was developed. It was tested for some gold deposits including Sukhoi Log. It allows to overcome preg-robbing activities of ores treated and to improve dramatically performance of cyanidation and adsorption circuits. The studies on refractory gold ore treatment including bio-oxidation, pressure oxidation, roasting and ultra-fine grinding were conducted. Heap leach technology was tested and introduced by Irgiredmet for a number of Russian mines. Zinc cementation, activated carbon and ion-exchange resin adsorption were used for gold recovery from pregnant heap leach solutions. The options including combined technology ?Heap leach/ RIL or CIP? for clay ores were also developed and tested. The plant using developed technology is at construction stage now. The study on In-Situ gold leaching was conducted. The comparison of different gold lixiviants for this purpose was carried out. Gold recovery from pregnant leach solution by activated carbon and anionite including gold elution from loaded adsorbents etc. was also studied. In 2000 the In-Situ leaching technology was commissioned at Maminskoye gold deposit (Ural). The technologies for treatment of complex ores and by-products were proposed. For example, the technology of gold, silver, copper and zinc recovery from calcines after sulphuric acid production was developed.

Jan 1, 2014

New technology for on-line particle size analysis of mineral slurries has opened up new applications for particle size measurement. In some cases the particle size distribution of the final concentrate is an important quality issue. This paper discusses established on-line particle size analysis technologies and presents experiences on the use of a new technique employing laser diffraction in several minerals processing operations. The main innovations in the new instrument are a simple dilution system and multiple scattering correction algorithm, which allows wide solids content variations of diluted sample in the measurement cell. Representative sample for laser measurement is produced by a simple and reliable dilution system. The applications discussed are; Blaine number measurement of Fe concentrate before pelletizing, grinding of variable batches of ore and paste thickener control.

Jan 1, 2014

By l. Bokányi, T. Varga

"The recycling of waste car tyres is a very important environmental task. The waste tyres usually are re-used or recycled by thermal processes like pyrolysis, gasification or incineration. The main problem associated with these processes is the sulphur content of waste tyres originated from the vulcanisation process, which pollutes the environment and the valuable products (i.e. pyrolysis oil) as well. In our research the desulphurisation of waste, mechanically prepared tyre sample was systematically investigated by the biosolubilisation with Acidithiobacillus thiooxidans, strain Karitas. Parallel, the experiments with sterile 9K nutrient medium were also carried out. It was found that the vulcanisation sulphur can be solubilised due to both the bio- and the chemical leaching, although the bioleaching is more effective. The solubilised vulcanisation sulphur then forms precipitates. The precipitates are forming in the bulk solution, as well as on the surface of rubber particles. The origin of the precipitates was investigated using XRD and scanning microscopy with micro probe. The origin of the precipitates is different: while in the process of the vulcanisation sulphur solubilisation with 9K medium the jarosite (KFe3+3(SO4)2(OH)6) forms, the course of the biosolubilisation with Acidithiobacillus ferrooxidans Karitas is accompanied by the formation of the jarosite and the halotrichite (FeAl2(SO4)4 · 22H2O) as well. The formation of the latter is the biomineralisation. The mechanisms of the bio- and chemical solubilisations are rather different as it was found and experimentally proved by several tests, and depends on the retention time of the solubilisation. Special efforts were done to elaborate the proper separation of the precipitates from rubber particles. Combination of intense dynamic stirring and recycling flotation process to remove the precipitates was applied for this purpose. The surface properties of synthetic jarosite were revealed using zeta-potential measurements at different pH and in presence of collectors. The parameters of the flotation were chosen based on the revealed surface properties of the precipitates. Finally, the sulphur recovery of the recycled rubber was achieved as low as <0.5%, sulphur content of it 0.17%, 12-times lower than that of the waste tyre sample after mechanical preparation."

Jan 1, 2018

By Azin Zangooi, Cesar Gomez, James Finch

Frother concentration is a variable which significantly affects the flotation performance by decreasing bubble size and helping froth stabilization. Variations in frother concentration, which mostly go unnoticed in industrial operations, may affect these functions. Some factors that can cause variations include the fact that frothers are normally dosed based on feed tonnage and not solution concentration, unstable frother delivery, incomplete dissolution for low solubility frothers, addition of frother-free wash water, remnant frother in recycle waters and frother partitioning to the froth. A colorimetric technique developed for determining frother concentration on site makes it possible to detect the occurrence of these problems and to establish their magnitude, allowing conditions to be adjusted to reduce frother concentration variations. By sampling and analysis, frother distribution throughout a circuit can be established, referred to as ‘frother distribution mapping’. Experiences at several concentrators processing sulphide ores are used to illustrate time restrictions for sample analysis, and to demonstrate temporal and spatial frother concentration changes as a consequence of variations in the grinding stage, recycled waters containing frother, and frother partitioning.

Jan 1, 2014

By Y. C. Liu

Ningxiang-type iron deposit is a most important sedimentary oolitic hematite deposit in China. Its? detected ore reserves are 3.72 billion tons, which is 73.5% of all detected reserves, and there are about 10 billion tons of prognostic resources. It is considered as the ?poor mine? for a long time be-cause of its difficult prooerty. But based on the ore characteristics of different deposits, the technological characteristics of ore are different with great diversity in ore baring horizon, distribution range, deposit scale, ore petrology, ore mineral assemblage and iron content. Through the study of deposit features and technological mineralogy of different Ningxiang-type of iron deposits in China, and based on industrial types and natural types of ore deposits, we divide different technological types according the technological features of the ore such as mineral composition, particle size, dissemination, occurrence of useful elements and harmful elements, the main physical and chemical properties of mineral and geological conditions of deposits, etc, moreover, propose the different utilization, mineral processing technologies and product schemes for the different types of ore.

Jan 1, 2014

By C. L. Tang

Parts of the wastewater are reused directly and the rest moderately purified and reused, so the utilization rate of wastewater of the whole processing plant reaches 100 percent. At the same time, beneficiation indicators have been improved stably, and great economic and social benefits have been achieved.

Jan 1, 2014

By Ingvar Ymén, Anders Sandc, Jan Rosenkranzc, Lisa Malma, Ann-Sofi Kindstedt Danielssonb

The understanding of particle surface properties is essential for the study and evaluation of froth flotation phenomena, particularly in the investigation of various chemical or reagent effects. Dynamic Vapor Sorption (DVS) is a method used for the analysis of surface properties of powders for instance in the pharmaceutical industry. To the knowledge of the authors, it has however not been used before in applications related to mineral processing. The DVS technique involves measurement of the water uptake of a relatively small amount of sample as a function of the relative humidity (% RH) in a temperature-controlled environment. The purpose of this work was to evaluate the method and investigate how it can complement existing techniques for surface characterization in mineral processing. Four samples (feed, CuPb concentrate, Cu concentrate and Pb concentrate) from the Cu – Pb flotation process in the Garpenberg concentrator, Sweden, were analyzed by DVS and the traditional capillary absorption technique (Washburn capillary rise). This enabled comparison between the two methods and evaluation of their respective advantages and disadvantages. Both methods give the expected ranking of the hydrophobicity for CuPb concentrate, Cu concentrate and Pb concentrate, but a discrepancy was observed for the feed. Washburn gave a value for the contact angle which was in the same range as for the CuPb concentrate, whereas DVS gave a value for the moisture uptake which was much higher than for the CuPb concentrate. Thus, DVS ranks all samples correctly, but with an unexpectedly high value for the feed whereas Washburn gives good ranking for three samples out of four. Potential reasons for the discrepancies are discussed.

Jan 1, 2018

By I. Grigoryeva, G. Voiloshnikov, V. Dementyev, N. Moskaeva, N. Voiloshnikova

"Adsorption processes with use of anion exchange resins are widely applied in the gold mining industry of Russia and the former Soviet Union. Anion exchange resin AM-2B and its analogs (with mixed basicity) are used as adsorbents. This paper focuses on the study of weak base anion exchange resin and its comparison with AM-2B resin. Different nature of the ion exchange groups of the adsorbents mentioned above provides essential differences in their properties both during adsorption and elution of gold and silver. Multistage gold elution and resin regeneration procedure is used for AM-2B resin whereas alkaline cyanide solution is used for weak base resin and allows for the reduction Capex and Opex in comparison with AM-2B resin. Anion exchange resins AM-2B and PuroGold S-992 were tested. Weak base resin is sensitive to pH of adsorption medium. Optimal pH value is 10.1-10.3 (at ?? >10.5 gold loading onto resin decreases dramatically). Adsorption isotherms for gold, silver, nonferrous metals, cyanide and thiocyanate ions from synthetic individual metal cyanide solutions were defined. Adsorption of all components onto PuroGold resin was lower than for ??-2? resin. Adsorption of metals from the solution with equal molar metal concentration (0.1 mg-equivalent/L of each metal) was also studied. The affinity of resins to cyanide metals complexes was established. Weak base resin has higher selectivity to gold in comparison with ??-2B resin and is less sensitive to ion composition of cyanide solution or pulp treated. Weak base resin was tested for gold recovery from gold ores. On the base of test results it was recommended to introduce this resin at some new plants in Russia. Commissioning and operation performance of gold plants confirmed efficiency of weak base resin use."

Jan 1, 2014

By L. Gutierrez, R. Yepsen, F. Alarcón

Chile is the world's largest copper producer which is mostly in the form of sulfides for which froth flotation is the most efficient concentration process. As a result a concentrate that contains high concentrations of copper sulfides such as chalcopyrite, chalcocite and enargite is obtained. In the last decades processing of ores containing high concentrations of enargite (Cu3AsS4) has continuously increased in Chile, which is related to the fact that ore deposits nawadays are more heterogeneous and complex. Enargite is a mineral that contains arsenic and its presence in the copper concentrates implies severe penalties. In addition, the shortage of fresh water has driven the search for new alternative sources of water, among which seawater has proved to be one of the most attractive. The objective of this research is to study the behavior of the enargite in the process of flotation using seawater, and at the same time to compare its behavior with the results obtained using conventional water. The study was carried thorugh micro-flotation tests using pure samples of enargite, at pH values ranging from 4 to 11, both in fresh and seawater. PAX and MIBC were used as collector and frother respectively. Micro-flotation tests were also done at different redox potential conditions so that the effect of the surface oxidation of enargite was evaluated in seawater. The results indicate that the recovery of copper from enargite is reduced in seawater compared to fresh water, in particular at the pH values close to those of the formation of the first hydroxy complexes of Mg and Ca. In general, the experimental data indicate that the floatability of enargite is strongly affected when seawater is used, in particular at oxidizing conditions. These results suggest that Mg2+ and Ca2+ ions contained in seawater interact with the surface of enargite forming hydrophilic species.

Jan 1, 2018

By A. K. Suri

India plans to increase the nuclear power share in overall energy-mix to about 30% by 2032 using both indigenous and imported reactor technologies. In the immediate time-frame, it is envisaged to generate 10000 MW electricity by PHWR technology by 2020 using indigenous uranium resources. This necessitates setting-up of new uranium mills and augmenting the existing resource, mining and milling capacities. This paper describes the current status and future R & D needs towards achieving the targeted demand of yellow-cake. Keywords: uranium, hydrometallurgy, leaching, yellow cake

Sep 1, 2012

By H. Matsuoka, M. Kawata, K. Haga, K. Mitsuhashi, C. Tokoro, A. Shibayama, R. Kawarabuki

"The mineral surface characteristic is important for the flotation because it affects the flotation behavior of the mineral. Conventionally, in the flotation process for Cu sulphide ores, the degree of ore floatabilities varies depending on the mineral phase such as chalcopyrite, bornite, or chalcocite. Therefore, mineral surfaces are treated with activators and depressants to control the floatability of target minerals and obtain high recovery performance. There are lots of flotation reagents which have many effects on ores depending on ore characteristics and conditioning methods. For example, sodium hydrosulphide (NaHS) as activator is known to have the effect of resulfurizing and activating oxidized surface of chalcocite and bornite. On the other hand, NaHS is reported to depress chalcopyrite floatability. In this study, the evaluation of mineral surfaces was conducted to predict flotation behavior. Activation of Cu minerals (chalcocite, bornite, and chalcopyrite) by NaHS was experimented. The three Cu minerals were treated in two steps. Firstly, they were oxidized in the drying oven. Secondly, they were treated with NaHS solution. After each treatment step, each mineral was measured by contact angle apparatus then analyzed by X-ray photoelectron spectroscopy (XPS). The results of surface characteristics after oxidation and NaHS treatment were utilized to accomplish the study’s objective. INTRODUCTIONCopper sulfide minerals such as chalcocite (Cu2S), bornite (Cu5FeS4), chalcopyrite (CuFeS2) are well-known abundant copper-containing minerals. Generally, these minerals are recovered and concentrated via collector flotation. In flotation, the wettability of the mineral surface is an important factor in its recovery. When the surface is hydrophobic, the mineral has high floatability and when the surface is hydrophilic, it has low floatability. Usually, Cu sulfide minerals have high floatability. However when their surfaces are oxidized, their floatability becomes lower in flotation. In this case of surface oxidation occurrence, activators are added before flotation to modify the surface property of the Cu sulfide minerals so that they can be floated at a certain flotation condition. Sodium hydrosulfide, NaHS, is known as one of the activators. Zhao et al. (2018) reported that NaHS is often used as sulfurizer for oxidized sulfide minerals (Becker et al., 2014, Clark et al., 2000, Newell et al., 2006, 2007, Newell and Bradshaw, 2007). Although the floatability of Cu sulfide minerals was raised by adding NaHS generally, the results of this flotation study showed that the flotation behaviors of mixed chalcocite, bornite, and chalcopyrite were different. Therefore, it was considered that NaHS works differently for each mineral."

Jan 1, 2018

By Valentine Chanturiya, Irina Khabarova, Maria Ryazantseva, Igor Bunin

"XPS investigations of the influence of HPEMP - treatment duration on the surface composition for natural chalcopyrite and sphalerite are described. HPEMP is a video pulse with a nanosecond front lasting between 5 and 10 ns. The electrical field component can reach 30 kV, whereas pulses repetition frequency is 100 Hz. In general, the formation of metal-deficient surfaces, polysulphides or elemental sulphur and oxides/hydroxides, were determined during the treatment for both sulphides as well as the essential differences of the way of mineral surface transformation during the treatment. The chalcopyrite surface shows the formation of elemental sulphur under the HPEMP treatment at 103 pulses while appearance of unstable sulphite species was detected at the chalcopyrite surface within 5 seconds (0.5•103 pulses) under the same treatment conditions. The results indicate that the quantity of adsorbed water (at.%) is changed considerably during the HPEM - treatment depending on treatment duration for both minerals. The concentration of water onto the chalcopyrite surface decreased during 30 seconds (3•103 pulses) of the HPEMP - treatment and it rose after the treatment at 5•103 pulses. The inverse dependency was obtained for sphalerite surface. Single mineral flotation tests have shown the significant increasing of the minerals recovery."

Jan 1, 2014

In this paper, various methods, such as XPS, XRD, SEM and zeta potential measurement are applied to investigate the action mechanism of sodium sulfide in flotation of lead and zinc oxysalt minerals. The experimental results show that the mechanisms of sodium sulfide in flotation of lead oxysalt minerals and zinc oxysalt minerals are different: on the surface of cerusite, there is lead sulfide phase formed under the reaction of sodium sulfide, resulting that the cerusite surface shows the form of galena, which is advantageous to the adsorption of anion collector and improves the floatability of cerusite as a result. On the surface of zinc oxysalt minerals, there is no zinc sulfide phase formed, but the sodium sulfide increases its surface electronegativity, and enhances the adsorption of cation collector lauryl amine, so the floatability of zinc oxysalt minerals is improved. The difference of action mechanisms of sodium sulfide on lead and zinc oxysalt minerals exactly explains the reason why different collectors are selected in the flotation of cerusite and smithsonite, which are both carbonate minerals although.

Jan 1, 2014

By T. Damyanov

Spherical grinding media (balls) are the most widely used media for comminution of ores by grinding. A modelling simulation study of the behavior of two grinding media in the grinding process was conducted to determine the possible advantages of the new shape milling bodies called tetraballpebs. Tetraballpebs are in the shape of tetrahedrons with spherical convex walls. A three dimensional CAD model of the mill drum with a diameter of 1200 mm was used. A continuous operating mode was simulated in terms of the 3D contact elements of the model (milling bodies and mill drum). Simulation tests were carried out in a typical grinding mode and at a typical rotational speed of the drum mill (75 per cent of the critical speed in cataracting mode). Studies carried out with both grinding media include equal number of milling bodies with the same weight and volume. Having thus ensured a uniform mass of the grinding media and same number of milling bodies, and constant other conditions and process parameters, conclusions can be drawn about the influence of the shape of the milling bodies on the grinding process. A kinematic analysis of the system using CAE (computer-aided engineering) model parameterization was conducted. The controlled parameters are: ? Power draw; ? Kinetic energy of each milling body; ? Motion of milling bodies inside the drum Keywords: grinding, grinding simulation, balls, tetraballpebs, DEM, CAD-CAE

Sep 1, 2012

By W. G. Wu

More and more researches and applications of organic chelating agents as depressors or activators are carried out in the course of research and application of modern flotation. The paper puts forward the necessary condition of organic chelating agents as depressors or activators by analyzing the chelating chemical performance of organic chelating agents with metal ions and the stability of chelates formed by them; at the same time, puts forward four sufficient conditions of organic chelating agents as depressors or activators according to different hydrophilic capability of the chelates and different performance of depression and activation of organic chelating agents for minerals. Namely, the ?1+1/4? necessary and sufficient conditions of organic chelating agents as depressors or activators are put forward.

Jan 1, 2014

By C. Y. Sun

In this paper, the development of research and practice on the separation process of fine complex Cu-S ore at a Copper Mine in south of China, was discussed. Since early 1980s, various processes were used, such as the process of bulk flotation-separation, the process of selection flotation and the process of iso-flotation. Especially when the process of selective flotation was put into operation, further development was achieved in beneficiation results, but the difficulty in separation of chalcopyrite from pyrite has not been solved yet, so causing a poor quality of Cu concentrate. The author has successfully developed a new separation process characterized by the use of collector thionocarbamate and fast flotation. The selectivity of fine chalcopyrite and pyrite was greatly improved. This process supplied a new route for the treatment of fine complex Copper sulphide ores.

Jan 1, 2014

By Shi Shuaixing Zhang Yuejun, Fan Xuesai Zhangming

"For the traditional principle of flotation cell design, or in the perspective of some researchers, the mixing effect of impeller for flotation cell is not only to suspend the particles off the bottom, but also to mix slurry well to achieve a uniform system. But for some special processing conditions, the depth profile of slurry concentration and particle size demonstrates an obvious difference. In the part around of the impeller in the cell, the slurry concentration is much higher than the part below the lip.For the vanadium titano-magnetite flotation process, distinguished with high concentration and large coarse particle size fraction, even though the concentration is very high, it can reach good gas dispersion, which is a fundamental principle for flotation cell design and application. The gas dispersion is not a challenge in the high slurry concentration environment, not only in the vertical direction, but in the cross section. Different levels (the distance from the lip is 400mm, 700mm, 1200mm, 1700mm, 2200mm, 2700mm) slurry in the flotation cell is sampled and analyzed. The slurry concentration of the 3 levels(1700mm, 2200mm, 2700mm) is about 55%, but the slurry concentration decreases from 55% to 25% sharply towards the lip.Therefore, a new understanding and viewpoint is presented, that the uniform system of slurry is not always reasonable for all of the flotation process. For some special process, if the coarse particles are needed to agitated well and transported to the upper cell, the quiescent zone in the upper cell will be destroyed and enhance the detachment probability for the coarse particles. The difference of slurry concentration and particle size fraction benefits the air dispersion and coarse mineral particles recovery.1.INTRODUCTIONNowadays, flotation is the most widely used separation process in the mineral processing industry. The importance of flotation technology in the global economy is significant. A rough estimate of the quantity of crushed ore treated by flotation is about nine billion tons per year, and the portion of base metals processed using this method is approximately 95% (Brewis, 1996)."

Jan 1, 2018

By S. Chuanyao

In last decade, along with its booming Chinese economy, China?s higher education has experienced rapid growth. In 2010, the number of various colleges totals more than 3500, with 2.2 million faculties registered. Currently there are almost 30 million students studying in the colleges, 3 times more than 10 years ago. Mineral Processing was initiated in 1949 as a sub-discipline of Mining Engineering, one of the 13 first level disciplines. Mineral Processing is now established in 34 Chinese colleges, recruiting 2600 undergraduate students, 540 postgraduate students and 100 PhD students every year. A further 9 institutes offer postgraduate education in this field. More than 3000 graduates majoring in Mineral Processing join the industry or institutions each year. The four-year undergraduate teaching and practical training in the colleges is designed to produce qualified mineral processing professionals. This includes courses in mathematics and natural science, fundamental engineering and basic and specialization courses. Recently, the ?Excellent Engineer Program? was launched to strengthen students? practical capabilities. This is a 3+1 teaching and training model; 3 years of theoretical course study plus 1 accumulated year of various practical studies, either inside or outside the college. As for graduate employment, mining-related major graduates have been in a good demand thanks to the intensive investment in mineral sector by Chinese companies. The shortage of experienced metallurgists generates a greater than 90% employment rate for Mineral Processing graduates. However, the biggest problem we are still facing is the gap between the quality of the graduates and the requirements of industry, as a result of occupation attraction, teaching systems, faculty quality, and so forth. Another problem is international orientation. Although nowadays Chinese-foreign cooperation in college education is popular, collaborative mineral related projects are far less common, leaving much room for improvement. Looking ahead to the next 10 years, we still have the right reasons to estimate continued prosperity in the minerals sector as well as mineral processing education in China. A brief analysis and views on this will also be shared in the presentation. Keywords: China, mining engineering curriculum, excellent engineer program

Sep 1, 2012

By F. Karakas

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

Sep 1, 2012

By A. Mainza, I. Govender, J. Waters

"The study of the properties of mineral processing suspensions is important in understanding how a circuit might behave. As soon as the predominantly dry ore enters a wet milling stage the ore properties undergo changes as a ‘slurry’ is created. Slurries can be classified in terms of their physical properties (particle density, solids concentration, particle size and size distribution, particle shape), and their flow properties such as rheology. Slurry flow regimes are classified into true homogeneous, pseudo homogeneous, heterogeneous and fully segregated, and only true homogeneous and pseudo homogeneous suspensions can be characterized by their flow structure. A class of the heterogeneous regime are the so-called dense phase or settling slurries - those which result in a clear water surface on standing, although they may approach a pseudo homogeneous state if suspended for a sufficient period of time. They are usually extremely difficult to characterize by their rheological properties alone and the rheological characterization of these slurries has always posed a problem, especially at higher concentrations. Previous rheological studies have focused on the individual concentrator units dealing with milling, classification, pumping, flotation, fine grinding, thickening.In this work an attempt was made to characterize two ore types (copper and a Platreef platinum ore) using a custom built Paterson and Cooke tube rheometer, at concentrations up to 43% by volume. After applying a turbulence correction, results showed Bingham plastic behavior. A conventional vane rheometer was then used to compare the rheological behavior of platinum concentrator streams. A size criteria was used to identify any rheologically dominant streams."

Jan 1, 2014