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By D. I. Verrelli

Within the flotation community a belief has developed that some particle shapes are more ?floatable? than others. This is usually attributed to an influence of particle shape or roughness on the induction period required to achieve attachment between the particles and the air bubbles in the pulp. Up to now, such measurements have not been able to readily isolate the effect on individual flotation subprocesses. In contrast, our experimental apparatus, the CSIRO Milli-Timer, enables us to directly observe the process of particle?bubble interaction and attachment by means of a high-speed video recording, thus providing a direct measure of the induction period for attachment. To assess the influence of particle shape on induction time we used two varieties of methylated borosilicate glass particles ? spheres and angular ?frit? ? in a range of tightly-sized fractions. In doing this, we take care to account for the influence of other factors that could affect the induction time, such as the polar angle of sliding commencement, and approach velocity. These parameters are recorded as variables for each interaction, and corrected for using multiple nonlinear regression. Our results illustrate the importance of particle shape on induction period, with angular particles exhibiting induction periods that were an order of magnitude lower than those of spheres. Furthermore, the induction period was seen to decrease with increasing particle velocity, or kinetic energy on approach, but increased as the trajectory approached the limit of just grazing the bubble. Particle shape in mineral processing is a consequence chiefly of the mineral type and the type of grinding employed. The results presented herein indicate that attention should be paid to the shape of particles obtained from the grinding operation, besides particle size. Keywords: attachment, bubbles, flotation, induction period, particles, shape effects, surface roughness

Sep 1, 2012

By Di Liu, Yongjun Peng

"It was identified that clay minerals adversely affect fine coal flotation through slime coatings. In the study, it was interesting to find that an anionic polymer dispersant, lignosulfonate, successfully mitigated the negative effect of clay minerals in coal flotation using fresh water, but in saline water, it exacerbated coal flotation.In order to understand the mechanisms underpinning the different behaviour of lignosulfonate in coal flotation using fresh and saline water, the adsorption isotherm, and dynamic light scattering (DLS) measurements were conducted in this study. While DLS monitored the molecular conformation change (swelling or shrinking) of the polymer in fresh and saline water, adsorption isotherms enabled polymer adsorbed amount on clay and coal mineral surfaces to be determined. It was found that lignosulfonate adsorbed on the coal and clay mineral surfaces providing effective electrostatic repulsions and resulting in a mitigation of clay minerals from coal surfaces in deionised water. In the presence of saline water, however, polymer molecular conformation changed. Polymer molecules were compressed and adsorbed in form of aggregates. The adsorption amount of lignosulfonate on clay minerals increased in saline water. A low dosage of lignosulfonate could not provide sufficient electrosteric repulsion to disperse clay minerals. Moreover, the high adsorption amount of the polymer on coal and clay surfaces led to a more hydrophilic coal surface, and coal flotation was therefore depressed in saline water. This study provides a new insight into understanding the role of anionic polymeric dispersants in mineral flotation using different quality water."

Jan 1, 2014

By A. J. Lynch, D. K. Tungpalan, Y. Reja, E. C. Avelar, G. Figueroa, S. Gómez, R. Alanis, M. A. Corona-Arroyo

"Have you been on a mine site? This question was posed by Emeritus Professor Alban Lynch to Higher Degree by Research (HDR) Students from the Sustainable Minerals Institute - Julius Kruttschnitt Mineral Research Centre (SMI-JKMRC) in the Student Technical Presentations in 2015. From that question, five HDR students from SMI-JKMRC organised a placement on mine sites in Mexico. The SMI-JKMRC is well known for its tradition to provide their students with opportunities to enhance and test their skills in mineral processing plants. The Student Venture became a short internship for HDR students which had the objective of establishing collaboration with mining companies in Australia and overseas, and of providing a unique experience for the HDR students in regard to their training, professional development, networking and cultural interchange. In return for the companies’ support, the students conducted plant audits to evaluate the process performance thereby providing valuable data to the host company. The 2016 Student Venture was held at the Grupo Peñoles & Grupo Fresnillo in Mexico, in which three mine sites received five HDR students from JKMRC and one young researcher from Universidad de Guanajuato (UG). This paper describes the positive outcomes for the mining company and the students for this experience. The Venture was considered very successful, as it provided valuable training for the students as well as in depth information about the operation of the comminution and flotation circuits of the host sites for the Grupo Peñoles & Grupo Fresnillo. The experience also provided an opportunity for an exchange of knowledge between the HDR students and the site personnel from the host operations. The indication of the success of the experience for all involved was the support of the host company in future student internships."

Jan 1, 2018

By Zoran S. Markovic

The extensive laboratory investigations were carried out in order to determinate behavior of sulphide and nonsulphide copper bearing particles during the flotation. The present ore sample were contained 0.55% Cu with 20.1% of nonsulphide copper in it and gangue material with higher contents of alumina about 19.07%. In this paper will be presented some results such as: effect of particle size, pH and applied collectors. The main goal was in application of collectors S-7518, as well as mixture of KEX and Z-96. Z-96 is a product from Chemical Industry Zupa Krusevac which was used as auxiliary collector in mixture with xanthates. The best results were done with this mixture in ratio KEX / Z-96 as 77/23 % in area of oxidized minerals flotation, but the collector S-7518 was achieved better results in sulphide mineral flotation. The S-7518 has better selectivity between copper minerals and pyrite comparing to mixture of KEX/Z-96 in mentioned optimal ratio. Flotation recovery and copper grade in concentrate were studied by flotation kinetics tests.

Sep 1, 2012

By C. R. Mambote

One of the processes developed for vanadium recovery from the fly ash of crude oil is through acid leaching. In the process, iron is one of the impurities that should be removed before vanadium precipitation, due to the fact that iron tends to co-precipitate with vanadium. The mechanism of iron precipitation is understood in terms of ferric hydrolysis, followed by the dimerization and subsequent polymerization of the crystalline iron compound. In order to develop a new approach for the fly ash processing, in the present paper the precipitation of iron from the liquor after the leaching process was studied with addition of NaOH or NH4OH in the presence of H2O2 or Na2C2O4 at 80°C. The objective was to investigate the feasibility of the selective precipitation which could be applied to vanadium and nickel recovery from the fly ash. The experimental results show the difficulties of removing iron by precipitation without co-precipitating nickel and vanadium.

Jan 1, 2014

By Megan Becker, Cyril O’Connor, Jenny Wiese, Gaynor Yorath

The effect of particle shape on true flotation has been widely reported. The present paper presents results obtained in investigating the effect of particle shape on the entrainment of particles during the flotation process. Different hydrophilic minerals with particles of varying aspect ratios were used and their shape determined using rheological tests and QEMSCAN. Their entrainment properties showed a close relationship to their shape with the recovery due to entrainment increasing as the aspect ratio of the particles increased. The effect of surface charge, by changing pH, and size of particles showed that the effect of shape was sustained at different pHs and particle sizes. Proposals are made to explain these observations in terms of the known relationships between drag coefficients and terminal velocities and shape. Since it has been previously reported that different milling procedures can affect particle shape, these results indicate that it is possible that such different procedures may result in increased entrainment of hydrophilic minerals.

Jan 1, 2014

By Y. F. Guo

Among the different valences of vanadium, V (?) is insoluble in acid, V (?) and V (?) is in-soluble in water but soluble in acid. Vanadium mainly exists as V (?) in vanadium titanium-rich material obtained by reduction -milling-separation from vanadiferous titanomagnetite. Therefore, the vanadium titanium-rich material can not be used to extract vanadium by acid directly. In this paper, the vanadium leaching was studied by oxidation roasting and acid leaching. Through oxidation roasting, vanadium is transformed from the insoluble V (?) into V (?) or V (?) in order to improve the leaching of vanadium. The results show that vanadium leaching increases significantly by oxidation roasting-acid leaching. Leaching of vanadium is up to 70.18% under the optimized conditions of roasting temperature of 950 ?, roasting time of 40 min, sulfuric acid concentration of 40%, leaching time of 4h, leaching temperature of 95 ? and liquid to solid ratio of 4 : 1.

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 V. Y. Dementyev

Laboratory and pilot-plant testing using a sample of gold-bearing semi-oxidized ore from a Russian deposit followed by a flow sheet and reagent flotation mode development to design a plant was carried out in IRGIREDMET in 2009-2010. According to the developed flow sheet low alkaline flotation conditions are recommended in order to activate the surface of sulfides. The pH lowering from natural (7.5-8.0) to optimal (4.6-4.8) value using sulfuric acid provides for an increase in gold recovery. Before CIL, a final flotation concentrate is pretreated using pressure oxidation. It was found that the use of recycled solutions from pressure liberation in order to create acidic conditions for flotation instead of sulfuric acid during pilot-plant testing is recommended. The flow sheet offers the detoxification of remaining pressure oxidation solutions together with the flotation tailings. The carbonates presented in the tailings significantly reduce the consumption of lime for detoxification and allows for the use of two tailings dams instead of three. The first is used for the tailings of flotation and pressure oxidation recycled solutions, which were detoxified together. The second tailings dam is used for detoxified cyanidation cakes of the flotation concentrate. It was found during pilot-plant testing that flotation under natural and acidic conditions provides for 88.9 percent and 93 percent gold recovery, respectively. 4.1Au percent increase recovery was achieved due to the reduction of gold losses with flotation tailings and better quality of concentrates.

Sep 1, 2012

By Chris A. Fleming

"The ability to recover cyanide from gold plant tailings has been known almost as long as the cyanidation process has been practiced, but there has been little incentive to process tailings in this way in the past. With the development of technologies that make it possible to recover and recycle free or complexed cyanide directly from gold plant slurry tailings, which indicates, on paper at least, significant cost savings compared to cyanide destruction, coupled with the introduction of legislation to seriously limit the discharge of cyanide to the environment in most gold-producing regions of the world, many companies are evaluating the cyanide-recovery alternative.There is arguably an even more compelling reason for mining companies to consider cyanide recycling. With the growing storm of negative public opinion that the use of cyanide in the mining industry is attracting - following several highly publicized spills over the last couple of years - the time has come for the gold industry to demonstrate environmental diligence and stewardship in the use of this commodity that is so vital for their industry. There is no doubt that the widespread implementation of cyanide recycling will reduce the impact of the cyanidation process on the environment, both by reducing the risk of spills (with less cyanide being transported from manufacturing plants to gold mines), and by reducing the loading of toxic and nontoxic metals and ions in the tailings.This paper briefly discusses the pros and cons of the different processes that are available for the treatment of gold plant tailings to regenerate and recovery cyanide for recycling, and presents a techno-economic argument for the incorporation of this technology into many gold plant flowsheets today."

Jan 1, 2003

By Paulo Sérgio de Oliveira, Joaquim D. Donda, Andreia C. Rosa

"The search for energy efficient technologies for comminution processes is constant in mineral processing studies, since those processes represent a major percentage of operational costs. In this context the use of stirred mills is increasing, especially for ultrafine grinding. Although many authors claim that these new equipment are more efficient than the conventional ball mills, there were very little chances to prove that in a practical way, since there are few industrial circuits where those technologies perform the same duty. Therefore, the regrinding circuit of Germano second concentrator offers an interesting opportunity: a vertical mill operating in parallel with two ball mills. During almost two years of operation, several sampling campaigns were conducted to evaluate the vertical mill performance and to compare the operational data of the three mills. The industrial data was also compared to jar mill tests results, which are monthly conducted in Samarco labs in order to predict the specific energy consumption required by the ore fed to these circuits. The vertical mill demonstrated the same ability to achieve the product specifications of the ball mills while proved to be able to reduce the medium specific energy consumption in about 40%."

Jan 1, 2014

By A. J. Lynch, L. Ergun, M. Oner

"A research program on modelling cement grinding circuits has been in operation at Hacettepe University, Ankara, for four years. It has concentrated so far on tube mill and air separator grinding circuits for cement clinker, with emphasis on plant sampling surveys, including axial sampling inside the tube mills. The methodology is to use plant data to build the models and to supplement this by laboratory data where necessary, for example the determination of breakage functions. The plant data come from comprehensive sampling surveys and so far 33 surveys of clinker grinding circuits have been carried out in 9 plants. The operating conditions have been• mill sizes – 3.2 to 4.8 metres diameter and 8.5 to 15 metres long,• mill feed rates – 46 to 158 tonnes per hour,• air flow through mills – 25000 to 125000 cubic metres per hour,• cement clinker work indexes – 10.3 to 18,• separator sizes – 2. to 3.1 metres diameter,• separator feed rates – 132 to 689 tonnes per hour,• separator speeds – 12.3 to 21 metres per second.The ball mill model is Whiten’s perfect mixing model and the separator model is the Tromp curve with a fish-hook. This paper emphasises on the importance of calculating the breakage rates and the discharge functions with three case studies at five different circuits which were selected for discussion because they show how particular features of circuit operation can be included in the general models. Size distributiongraphs are used to illustrate every aspect of the discussion.In case I the special emphasis on calculating the breakage rates and discharge rates separately is given in a high pressure grinding roll-ball mill-separator circuit. The tonnes of each size fraction in the mill and the calculated values of R/D, D and R are determined. The values of R per mw are also given to allow comparison with mills of other sizes. The circuit allows the comparison of the static type (V Sep) and dynamic type separators (SKS). Comparing the reduced efficiencies shows that the dynamic separator is slightly more efficient than the static one.In case 2 data are given from two compartment tube mills having the same diameter and the motor power but different ball size gradation. The breakage rate particle size variation of the second chamber of two mills indicate that having finer ball size distribution causes higher breakage rate values."

Jan 1, 2003

By Yuqing Feng, Ping Fang, Dezhou Wei, Zichuan Guan, Shuling Gao, Baoyu Cui

"Air core, as an inevitable phenomenon of rotational flow field inside hydrocyclone, has a major impact on hydrocyclone’s separation characteristics. The air core formation process, its structural features and its influencing factors were investigated systematically in this paper. Numerical study on the air core of a f50 mm hydrocyclone was carried out using a commercial computational fluid dynamics (CFD) modelling software package ANSYS/Fluent with the selection of Reynolds Stress Model (RSM) for the turbulence model and Volume of Fluid (VOF) for capturing the air-liquid interface. Physical experiments were conducted under the same geometry and operation conditions and the particle image velocimetry (PIV) technology was used to measure the liquid flow. The CFD results are compared with the experimental measurement with good agreement demonstrated. The air core was formed generally at around 0.7 s, air outsides of the air core was eliminated completely after 1.7 s. The centreline axial velocities and the water blocking hydrocyclone simulations showed that air of the air core entered the hydrocyclone from the underflow area and exhausted from the overflow area, but there was also some air flowing into the air core from the overflow area. The largest swing of the air core occurred on the top of the underflow pipe, and a protuberance similar to the shape of Adam’s apple appeared when the air entered the vortex finder. CFD simulation results also showed that the air core diameter was decided by axial position and parameters of hydrocyclone. The structural parameters have more effects on the air core diameter than the operational parameters."

Jan 1, 2014

By R. Venugopal

The paper reviews the development of Mineral Engineering education and training programmes in India. It highlights the major academic programmes and describes the evolution of the curriculum and design of courses in response to the changing requirements of India?s mineral and coal industries. An outline of the efforts needed to sustain and further improve the existing programmes is also provided. Keywords: manpower, mineral engineering

Sep 1, 2012

By H. Sarvamangala

Selective separation of alumina, silica, calcite and apatite from hematite was achieved through microbiologically induced flotation and flocculation in presence of bacteria (B.subtilis) and that of hematite from apatite after interaction with yeast (Saccharomyces cerevisiae). Bacterial and yeast metabolites containing extracellular proteins were characterized from mineral-grown cell free extract. Bacteria and yeast can adhere to mineral surfaces and influence subsequent separation of the minerals. Bacteria functioned as a stronger depressant for hematite, while yeast cells depressed apatite at neutral pH. Selective affinity of the bacterial and yeast cells towards the mineral surface was observed through adsorption studies. Extracellular proteins (EP) were isolated from B.subtilis and yeast. The protein profile of the EP of bacterial and yeast cells grown in presence and absence of minerals was studied. This study has demonstrated the utility and amenability of microbially-induced mineral beneficiation of iron ores through bacterial and yeast cells and their metabolic by products.

Sep 1, 2012

By Baidyanath Mandal

Technology in the solid-liquid separation industry has evolved rapidly during the last fifty years and from the beginning, DIEMME Filtration has played a very important role in this evolutionary process by developing innovative solutions, which are used for a diverse range of industrial applications. Since the last decade, we find more and more examples of filter presses employed in the mining & mineral processing field, where high performances in terms of productivity, dewatering capacity and mechanical strength even in extreme working conditions are required. Mainly the requirement of such high quality equipment comes from the Process, however in few cases the reason could be linked with the environment. For stringent process applications like Mineral Concentrates dewatering & leached Slurry Filtration, it requires a high quality & extremely reliable equipment. In these applications, since many years industries are achieving the desired result by using Diemme Filter Presses. Also, recently, due to stringent environment practices are been applied globally, industries needs equipments which could dewater a high amount of residues / tailings with minimal moisture content in the filtered cake. In comparison to all the conventional dewatering equipments, Diemme Filter Presses are most efficient for these kind of product & applications. Diemme Filtration is a highly professional & technological company with several decades of experience in designing equipment for mineral processing. We take up each project as separate & design and manufacture equipment based on individual process or project requirement. This presentation will be focused on the Solid-Liquid separation technologies & equipment Diemme Filtration offers to the mineral processing Industries. It consists of Diemme?s History, Global Network, Technologies & Expertise, R & D Capabilities, Manufacturing Range, Some Applications & results on different mineral processing. Keywords: solid-liquid separation, filtration, dewatering, filter press

Sep 1, 2012

By G. X. Du

Reaction kinetics of serpentine and hydrochloric acid is theoretical basis for optimizing reaction process conditions of serpentine and hydrochloric acid. Kinetics of serpentine and hydrochloric acid was studied in this paper. The results indicated that apparent reaction order to hydrochloric acid was two and reaction kinetic equation could be expressed as: 2HClHCl,ddtckct-=·. The diffusion rates of hydrogen ions in liquid film on surface of serpentine particle and in amorphous silica layer generated in the reaction and chemical reaction velocity during the reaction had important effects on to-tal reaction velocity. And chemical reaction velocity had the most significant influence. The relation of conversion rate of magnesia xMgO with reaction time could be expressed as: 1(1)xkt--=·.

Jan 1, 2014

With shortage of sulfide nickel ores, laterite ore was paid more attention by scientists. Because its grade is commonly lower than sulfide nickel ores, laterite ore can not be utilized effectively be-coming the bottleneck of study. Leaching laterite ores from Yuanjing, Yunnan province, organic ac-ids show better selective than sulfide acid in nickel and cobalt recovery. Organic acid has low de-pendent on pH, keeping leaching capability even higher than 3. On the other side, when pH up to 2, sulfide acid can not leach laterite ores any more. After four kinds of organic acid leaching laterite ores, besides citrate, malate and succinate have good leaching and effectively selective capability. Especially, succinate has the best selective leaching capability of nickel and cobalt in four kinds of organic acids for latter anion purification and separation. Isolated from waste water with sugar, Aspergillus niger (zs1) has great capability to produce organic acids and vigorous growth. Laterite ores have been respectively processed by direct-leaching and indirect-leaching. Indirect-leaching gives a better result than direct-leaching. Extraction of nick-el by indirect-leaching reaches 44.3%, far more than that of direct-leaching. Moreover extraction of nickel at pulp density of 5% is higher than that at pulp density of 10%, reaching 63% in 11 days and extraction of cobalt also is 48.1% in the same period. Compared with nickel and cobalt, iron gives low extraction in solution, containing organic acids produced by Aspergillus niger .

Jan 1, 2014

By M. Marinov

The Bulgarian deposits of quartz-kaolin raw materials are localized in the NE Bulgaria. For many years, the quartz-kaolin sand separation has been performing by water washing technology. After wet separation the raw material yields two products ? washed kaolin (different grades) and quartz sand (different grades). Research and development program has started to improve the quartz-kaolin sand separation. The program has undertaken an increasing of processing capacity, to decrease the losses in the tailings and to provide production of new quartz sand grades. The kaolin-silica raw materials from Vetovo open mine and the technological tailings from Vetovo processing plant were characterized. It was established that there are a lot of losses of quartz in final tailings. New approach on kaolin-silica raw material separation was tested in laboratory scale. The test work was performed on Derrick Stacksizer screening machines. The results of laboratory experiment show that there are possibilities to increase the quartz sand recovery and to start the production new grade sand. The full-scale pilot test was performed including the following units: two Derrick Stacksizer screening machines equipped with 0.430 mm and 0.150 mm opening Derrick Urethane Panel, respectively; Flat bottom DN 500 Hydrocyclone and DN 100 Hydrocyclon. The pilot test data clearly demonstrate that the Derrick Stacksizer screening machines are suitable for Bulgarian silica-kaolin raw material. Based on the test data a new quartz-kaolin separation technology was developed. The new technology was introduced in Vetovo processing plant increasing processing capacity and decreasing the losses of quartz in final tailings. Additionally the production of silica sand grade PK 0.16 is increased and starts the production a new grade PK 0.10.

Sep 1, 2012

By Yongfu Yu, Xiaotie Wang, Fuguang Zhang, Liping Che

"The flotation process of native Rare Earth minerals such as bastnasite, monazite, mixed minerals of bastnasite and monazite, using the new effective collector Dh was studied in this paper, respectively, and the flotation properties are described. The good qualities of the new collector Dh were revealed through comparing with other collector of Rare Earth minerals. The test results of different ore samples show that at moderate pulp pH (8.5-9.5), Rare earth minerals can be effectively separated from barium, calcium and silicon bearing intergrowth minerals (barite, calcite and silicate minerals) and high quality Rare Earth concentrates can be obtained successfully by the new collector Dh, acid silica gel, turpentine and reagents fitting together rationally. In order to determine optimum technical conditions, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents (Dh and acid silica gel) on the flotation were investigated in the test.Simultaneously, the paper explores the mechanism of the flotation of Rare Earth minerals from intergrowth minerals. The infrared spectra for Dh and Rare Earth cation by analysis in theory shows that Dh formed chelate complex with Rare Earth cation and were adsorbed on the surfaces of Rare Earth minerals. The mechanism of the intergrowth minerals depressed by acid silica gel can be explained as gummy colloid hydrolyzed from acid silica gel which are selectively absorbed on the gangue minerals, making them hydrophilic and depressed, with pulp pH value of alkalescent."

Jan 1, 2003