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By E. V. Manlapig, M. C. Harris

"The complexity of the flotation process has made the identification of an appropriate model structure, for use in the prediction of flotation circuit performance, far from obvious. Work performed under the auspices of the AMIRA P9 flotation program has indicated that the metallurgical performance achieved from a flotation cell arises from the interaction of two essentially independent property classes, namely the cell operating conditions and the properties of the cell feed stream. These observations have led to the development of a model structure that associates a constant set of flotation parameters to the streams of the circuit, which are transformed into a flotation response depending on the operating conditions within the flotation cell.A variety of alternative model structures exist within the literature which do not make this distinction between cell and stream flotation properties, and many of these models are in widespread use for flotation optimisation and design studies, both in industry and academia.In this paper, data collected from an industrial flotation circuit is used to derive the parameters associated with two different types of flotation models. Simulations performed using these models demonstrate the need to differentiate between cell and feed properties. A model that does not differentiate between these two properties fails to successfully predict the metallurgical performance of a flotation circuit after a disturbance."

Jan 1, 2003

By Pramila Misra, Jibardhan Meher, Debadutta Das

The concentrated coal-water slurry has been receiving considerable attention recently due its ability to replace fossil fuels. Attainment of stable and concentrated slurry has been succeeded so far through several physical and chemical techniques. The present article reports the formulation and stabilization of a highly concentrated coal-water slurry formed from five varieties of non-coking coals with variable ash contents obtained from Eastern part of India, employing three varieties of starch esters, such as starch benzoate, starch formate, and starch carbamate as dispersant. The apparent viscosity of the modified coal-water slurry has been measured by varying coal loading, dispersant percentage, pH, temperature, etc. The apparent viscosity of the slurry has been found to be decreased substantially on addition of 0.8% of adsorbate in the slurry. The particle-particle interaction has been considerably decreased and stable concentrated coal-water slurry containing high weight fraction of coal (61.5-63.5%) has been achieved in each case. The slurries stay in a non-settling form for about a month with viscosity in a permissible low range. The coal-water slurry has been found to behave as a non-Newtonian liquid. Comparison of the zeta potentials of the naked and modified coals evidences that adsorption of the dispersants at coal-water interface results in inhibition of the agglomeration of coal particles through mostly steric repulsions.

Jan 1, 2014

By Sanchita Chakravarty, Sumantra Bhattacharya, Divya Jyoti, A. K. Mukherjee, Soni Jaiswal

"Release analysis is independent of collector and frother dosage and type, but it is primarily influenced by the degree of liberation or “state of release of the sample”. The shape of release curve is an indication of the degree of liberation. This paper briefs about the effect of reagent combination, particle size and surface characteristics on the release analysis of difficult-to-clean LVC coal.Release analysis of three LVC coal fines obtained from two different coalfields of India was carried out at three different size levels such as -0.5mm, (-0.5+0.1) mm, and -0.1mm. The collectors used were n-dodecane and commercial diesel oil. Incomplete liberation of coal fines even at a size of -100µm, corroborated by photomicrographs of ROM and clean coal macerals, in a great measure reduced the flotation-based cleaning potential of the fines. FESEM images of fines reveals that the adherence of ultrafine onto the surface of relatively coarser particles reduced the clean coal recovery. The results obtained also appear to be coal, reagent combination and, particle size and particle surface specific. Only one coal indicated the liberation as is usually expected for -0.1mm particles with a reasonable yield of 65% at 18% ash. INTRODUCTION Froth flotation has a long history of being used to treat coal fines. Coal flotation is considered to be difficult, if the percentage of Near Gravity Material (NGM), i.e. essentially locked particles, in flotation feed is >10% [Aplan, 1993], which is usually the case with all the coking coal fines in India. The fines are rich in vitrinite, so valuable for coking coal. Unfortunately, there appears to be no standard procedures to determine the separation efficiency of froth floatation. Release analysis proposed by C.C. Dell in 1953 [Dell, 1953], aimed to determine the ultimate floatability of coal. Several other techniques had been proposed but release analysis technique has been considered to be a vast improvement over the batch flotation process [Forrest et al. 1994]."

Jan 1, 2018

By W. L. Jiang

Reverse-flotation technology is often applied in iron ore dressing plant, in order to enhance the quality of iron concentrate from magnetic separation. However, this technology has disadvantages in operating cost, energy consumption, and environmental protection. Developing innovative equipment to process magnetite ore more-effectively is a way to get rid of these disadvantages of reverse flotation and improve the quality of iron concentrate. This paper describes the development of Complex Flashing-Field Magnetic Cleaner, a new kind of equipment based on the principle of combination of separation in magnetic field and separation in gravity field. This innovative equipment possesses a tailor-made magnetic system and has the characteristics of a magnetic field, which can strengthen the formation of magnetic agglomerations and the dispersion of gangue minerals, improving the quality of separation. The automatic control system developed specifically for this equipment can further increase the accuracy of separation and stabilize the process. Test results showed that this equipment is reliable in operation, economically beneficial, and has large potential of application.

Jan 1, 2014

By Andrew Logan

Newcrest has a strong history of growth over the past 20 years, yielding value from previously marginal ore bodies. We have grown regionally in Asia Pacific through our operations in Australia, Indonesia and Papua New Guinea, and also established a beachhead in West Africa. The company has a reputation of realizing value from large, low-grade deposits adopting step change approaches. Newcrest is focused on an overall strategy of gold, low cost, long life and moderate growth. Capability step changes play a large delivery role. They transition from a business offline-to-online approach as opportunities mature. Newcrest believes in a) Knowing what ?good? looks like, b) An open innovation approach to actively working with others, c) The leap frogging leverage of making the ?old new again?, d)An adopt-adapt-develop methodology enabled by rapid prototyping/piloting, e) Getting our handsdirty with test work and plant analysis, and f) Staying focused on a few high business leverage areas. This paper describes Newcrest?s approach and our experiences in establishing renewed metallurgical processes, specifically aimed at increasing innovation adoption. Some of our step changes discussed include: 1) Early waste rejection to avoid high energy processing downstream, 2) Broader gold product channels to reduce site based processing needs, 3) Lower energy processing, and 4) Geo-Metallurgy approaches. Keywords: Newcrest, gold, step change, open innovation, adopt, adapt, develop, offline, online, prototyping, old new again, waste rejection, low energy, geo-metallurgy

Sep 1, 2012

By A. Zangooi

Frothers play major roles in flotation through interaction at the air/water interface. A method of determining frother adsorption density (coverage), i.e., the number of molecules per unit of interfacial area of bubble surface, is introduced. The technique is based on mass balancing the frother around a continuously operated bubble column. The mass balance requires collection of bubbles before they burst. The column design and operating procedure is reviewed, and some preliminary results discussed. Keywords: flotation, colorimetric frother analysis technique, frother mass balance, coverage

Sep 1, 2012

By A. Chattopadhyay

Porphyry copper deposits are the most important source of copper and also gold within the orogenic belts. These deposits are characterized by low grade copper ore (0.2% to 1% copper) and host precious metals like gold, silver and platinum. A characterization tool has been developed for complex porphyry type copper-gold deposits with an aim to quantify copper and precious metal deportment. This quantification is a challenging task due to low grades and also due to the presence of both visible and invisible precious metal content in different sulphide and non-sulphide phases. Studies were initiated on various complex, ore deposits and also on samples representing various processing streams such as flotation and leach products. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metals content in various species. The relevance of this characterization to metallurgy will also be briefly discussed in this paper.

Sep 1, 2012

By J. Yianatos

The regrinding stage is necessary to achieve the particle size (liberation) for the final upgrade in the cleaning flotation process. At present, vertical mills (Vertimill) are employed at industrial scale, using small steel balls as grinding media. The regrinding process characterization requires mixing regime knowledge along with the mean residence time of the liquid and solid phases. The residence time distribution (RTD) and the actual mean residence time estimations from theoretical relationships are complex due to the presence of three components (solid mineral, balls and water), mass transport characteristics and segregation affecting solid holdup. Therefore, the experimental RTD determination is suitable for industrial mills. In this work, RTD measurements were performed in two different industrial flotation plants. Both plants operate with Vertimills of 1000-1500 HP in the regrinding process with different circuit arrangements according to the plant treatment capacity. The RTD was measured using the radioactive tracer technique. This technique allows for non-invasive tracer detection where the procedure consists of selecting a liquid (Br82 in aqueous solution) or solid (irradiated solid) tracer for RTD data acquisition in real time. The RTD was modelled by the Large and Small Tanks in Series (LSTS) model, which allowed the characterization of the different mixing regimes for both liquid and solids in the regrinding mills. Effective mean residence times in the range 2-11 min were obtained with RTD shapes similar to those obtained in tumbling ball mills. It was found that residence times of liquid and fine particles were similar, which is consistent with results observed in other mixing systems, e.g. mechanical flotation cells. Also, the mean residence times estimated from the RTD allowed the mass balance adjustment to be validated from metallurgical sampling data. RTD estimations are useful for better understanding the Vertimill behaviour and to identify the actual breakage rates. Keywords: vertical mill, residence time distribution, particle size, modeling

Sep 1, 2012

By M. Saghaeian, R. Hejazi, R. Barreiro, M. Tavousi, M. Ahadi, O. Asghari

"Banded iron formations are the major iron source for producing high grade concentrate. BIF are generally lower grade and more difficult to extract. In order to know how best to process BIF ore, it require comprehensive knowledge on ore bodies even in the early stages of the mining process. Geometallurgy combines geological and mineral processing information and allows for higher flexibility in response to changes in the plant feed when mining different parts of the ore. This can lead to economic benefits, owing to improved plant operation, yet is time consuming and correspondingly costly. The main focus of this paper work has been to develop a comprehensive geometallurgical testing framework for developing Yogi BIF low grade magnetite deposit located at Western Australia. In order to provide successful geometallurgical mapping, was collected data from several different disciplines (geology, chemistry, mineralogy) and parameters (physical properties, metallurgical response and geotechnical measurements) during drilling activities and test work. The investigation shown magnetic separation behavior of material had high variation and is most important element in the proper design of ore beneficiation plant. This paper provides an improved and efficient magnetic separation test methods used for the investigation of separation behavior and variability of the Yogi Ore deposit and evaluates their applicability and potential in the geometallurgical context. In this paper a small-scale magnetic separation has been developed that allows estimating from single pass separation test using small amounts of sample material. Verification of the evaluation method and validation was done with different mineral systems."

Jan 1, 2018

By J. T. Liu

Packing in a flotation column is one way to increase separation efficiency and effective descending flotation-column height. In this paper, the difference between filling packing and sieve packing is described, and the flaws of filling packing in flotation columns in industrial application are pointed out. A change of flotation process and its effect on flotation results are reported. Based on sieve-plate filling, a high-efficiency mixed packing mode consisting of screen-plate packing and honeycomb-tube packing has been proposed, with the packing mode optimized in the cyclonic static microbubble flotation column in the separation zone. In the mixed packing mode, the honeycomb tubes are used to reduce the vortex effect at the base of the column and weaken the radial dispersion of jetting bubbles, and the sieve plates are used to comminute bubbles in the separation zone, to lengthen the bubble migration path, and to stabilize the foam layer. The superiority of honeycomb-tube packing is analyzed using bubble-particle collision theory, and the dynamic equations of collision probability are derived. The role of mixed packing in guaranteeing mineral recovery is analyzed by the axial dispersion method, and a dimensionless axial dispersion model is derived. When a high-turbulence flow is maintained, a static separation environment is formed in which secondary mineral processing is rendered more effective. In this way, a nonlinear separation environment is formed in the flotation column. Finally, mixed packing was applied in an industrial test. A large vortex developed at the base of the column. It was observed that the bubbles in the radial flow were homogeneously dispersed, the residence time of the pulp was prolonged, and the froth layer became thick and stable. Based on the test data, it was found that the sieve packing has the potential to yield a product of approximately 25.83% copper concentration with 91.78% recovery from a feed concentration of approximately 0.727%. If mixed packing were used, the product concentration could be further increased to 27.60% from a feed of approximately 0.739% concentration with 93.38% recovery.

Jan 1, 2014

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

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

Jan 1, 2003

By Markus A. Reuter, Bernardete Castro, Antoinette van Schaik, Han Remmerswaal

This paper describes the inseparable relation between product design, liberation, and metallurgical recovery in the optimisation of the recycling of passenger vehicles. This is illustrated by the use of an optimisation model that uses among others a material combination matrix based on metallurgical process data, which depicts the consequences of the quality of intermediate recycling products on the metallurgical material recovery and final alloy metal quality. Various simulations will illustrate the effect of changes in product design and hence liberation on the recycling of end-of-life vehicles. Although this paper focuses on cars, the discussion is equally valid for any end-of-life product. Calibration of the model will be discussed with reference to experiments carried out in order to study the optimal recovery of aluminium applications used in passenger vehicles.

Jan 1, 2003

By Tatyana A. Ivanova, Tamara N. Matveyeva, Anatoliy A. Fedorov, Tatyana V. Nedosekina, Valentin A. Chanturiya

An ingenious methodology purposively developed by the authors for comprehensive assessment of flotation properties, electrophysical characteristics and. crystal chemistry features of natural gold-bearing sulfide minerals of different origin has been used in this study. Examination of the elemental composition of the minerals, ion-molecular components of the liquid phase in suspensions, surface properties of sulfides and different flotation reagents sorption forms was performed using the methods of X-ray phase and spectral analysis, potentiometry, UV and IR spectrometry, computer image analysis, and computer simulation techniques. The role of isomorphous impurities in the formation of hydrophobic sulfhydric collector layers on mineral surfaces in complex ore processing has been elucidated. The parameters characterizing the variability of the Fe:S ratio in pyrite of different origin have been determined based on non-stoichiometry characteristics of natural gold-bearing sulfide crystals. An ingenious method of formatting and linear approximation of experimental data was used to find out the quantitative relationships between the impurity content, electrophysical characteristics, non-stoichiometry and floatability of pyrite from a number of different deposits. The effect of the impurity species present in sulfides on the characteristic pH value marking the floatability peaks as such and their trend of shift towards higher alkalinity has been revealed. A theoretical substantiation has been given to prognostic assessment criteria for processing characteristics of gold-bearing sulfide minerals with varying composition. New flotation reagents and advanced reagent systems which help to increase the contrast of processing characteristics for different gold-bearing sulfides, resulting in improved selectivity, have been developed. The mechanism of selective flotation of precious metal-bearing Fe and As sulfides achieved by using short-chain dithiocarbamates and a mixture of cyclic trithiocarbonate with oxyalkylsulfides has been analyzed.

Jan 1, 2003

The ultimate goal of a mineral processing plant is to recover as much of the target mineral(s) as possible from the ore being treated to achieve the best economics. Selection of the mineral processing techniques is the most important step in achieving this goal. However, due to the complexity of the ore, the recoveries of valuable minerals may be not satisfactory even when the mineral processing technique(s) are well chosen. In other words, minerals of interest can be lost to the tailings for mineralogical reasons. For example, gold is mainly extracted from the ore by gravity, flotation, cyanidation, or a combination of these processes, and high recovery (>90%) can be achieved when gold occurs as coarse grains. However, when a refractory ore is being processed, gold extraction will be challenged by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery mainly include grain size, shape, surface coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking in sulphide, silicate and other minerals as fine-grained gold inclusions and/or as invisible submicroscopic gold is by far the most common factor leading to poor gold recovery encountered in gold ore processing. Processing of PGE ores faces the same challenges as gold. Small grain size and locking of PGM in sulphide and non-sulphide minerals often cause PGM losses. When silver ore contains significant amounts of pyrargyrite, proustite and stephanite, silver recovery by cyanidation can be very low because of the slow dissolving kinetics of these minerals. In the processing of base metal ores, high content of pyrite, intergrowth of chalcopyrite with sphalerite and presence of clay miner-als may cause problems in recovering Cu-, Pb- and Zn- bearing minerals. Process mineralogy helps address all issues and problems related to mineral processing with predicting and trouble-shooting being two major objectives. It provides useful information on process selection, flowsheet development, recovery improvement and reagent consumption optimization. The information acquired from a process mineralogical study can be used as a guide for a metallurgical testwork program for process design or optimization.

Jan 1, 2014

By H. Z. Liu

An extra-refractory gold ore in China belongs to Carlin Type Gold Ore which is not only submicroscopic but also rich in arsenic and organic carbon. They have been proved that its floatability is not good enough and the gold in the ore could not be leached almost if it was not pretreated. The tests for the ore were carried out in accordance with flotation-concentrate preoxidation-cyanidation(or CIL) processes in order to exploit the mine. Two new depressants were discovered in the flotation tests and improved concentrate grades from about 20g/t to 32~50g/t. The methods of the concentrate preoxidation tests were alkaline atmospheric oxidation, acidic atmospheric oxidation, acidic pressure oxidation, roasting oxidation?biooxidation. The cyanidation tests after the concentrate preoxidation have proved the gold extraction of the pressure oxidation to be the highest(92.5%) and that of roasting secondary(89.3%). After fuller techno-economic comparison, it is suggested that the flotation-pressure oxidation or roasting-CIL process should be the most optimal for treating the ore. The gold recoveries of the ore were 83% for the pressure oxidation and 80% for the roasting respectively.

Jan 1, 2014

By Peter Kondos

The need for a sustainable development of ore deposits makes it imperative to be innovative and mindful in creating an economically and environmentally viable operation, while maintaining a good working relationship with the various stakeholders involved in developing and operating a large and complex mining project. This is becoming immensely important as gold ore deposits are becoming more mineralogically complex along with lower grades presenting both metallurgical and environmental challenges that need to be addressed in mitigating risks and improving project economics. This paper presents Barrick?s approach to development of strategic technologies for our long-term sustainable growth through conversion of valuable resources into reserves for both our green-field development projects and the expansion of our existing mining operations. Some of the key strategic solutions, including mineral processing, metallurgical and energy technologies, developed by Barrick and their impact on some of our complex gold and copper-gold ores will also be discussed in this paper. Keywords: gold ores, copper-gold ores, processing, breakthrough technologies

Sep 1, 2012

By C. Y. Sun

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

Jan 1, 2014

By Z. H. Zhang

Shizhuyuan is a world-class WO3, Mo, Bi and CaF2 poly-metallic deposit; it has rich reservation, but great difficulty in ore?s processing; thereby, for many years, it has been the target problem of beneficiation technologies. This paper, while briefly reviews its main scientific and technological advancement, pays special attention to the complete set of new technology and technical index achieved in recent years, which is characterized by using full-floatation flow-sheet as the backbone flow-sheet, explores some key factors influencing tungsten floatation, and presents a brief introduction to such new equipment as flotation column and comprehensive utilization of fluorite.

Jan 1, 2014

By W. Yao, M. L. Li, R. Cui

"The purpose of this research is providing a flotation process for recovery of lead in lead silver residues from a zinc smelting plant with a new hydroximic acid collector (HOC). The collecting ability and reaction mechanisms of HOC were investigated based on pure mineral flotation tests and analysis of zeta potential. The pure anglesite flotation tests showed that HOC has a good collecting ability for anglesite. Zeta potential measurements proved that HOC adsorbed on anglesite surface physically and chemically. The lead-silver residues in a zinc smelting plant with lead grade about 17.5% was used as raw material for flotation tests. The results showed that under the conditions of pH adjusting agent lime 500g/t, inhibitors sodium silicate 2000g/t, collector HOC 1500g/t, frother alcohol oil 75g/t, the grade of the lead concentrate can be reach 47.18% and the recovery was 76.39% by one roughing-one scavenging-three cleaning and middles back to the flow-sheet in turn after the lead-silver residues were washed by two stages of cleaning-filtration.INTRODUCTION Nowadays, with the increasing exploitation of natural mineral resources, more and more secondary resources should be researched and used for the valuable metals. Hydrometallurgical zinc leaching residues, which contain a considerable amount of zinc, lead, silver and other minor valuable constituents, is a typical and abundant secondary resources (Zhang et al., 2011). A huge quantity of zinc leaching residues (ZLR) had been produced per year (Jiang et al., 2017).This residues not only occupy precious land but also threaten the environment because of the dissolved heavy metals especially in rainy days (Han et al., 2014). Consequently, it is urgent to develop an effective and clean method to dispose this residues which can benefit not only in economical but also in environmental (Jha et al., 2001)."

Jan 1, 2018

By Xiaojing Li, Yueyuan Zhou, Shengyao Ma

The paper presented the acnalysis of field intensity of rare-earth permanent magnet with high BH product and the research of magnet configuration with narrow pole pitch on open magnet surface, both using ANSYS. The possibility to separate micro-disseminated feebly magnetic minerals by improving the field intensity and the capture line distribution rate on open magnet surface were verified. The research on the method to pile up magnets to increase peak value of field intensity on the open magnet to 1.0T was done through correlation analysis between shape and dimensions of magnetic material and field intensity. And the research on technology method to improve capture line distribution rate in the separating field to 1.25×105/m2 was done through optimization design of magnet configuration of the open magnet with narrow pole pitch. Laboratory tests were performed with hematite sample from ore dressing plant such as Hainan mine, Qidong iron ore, etc. The separation results acquired were at the same level as using the electromagnetic separator, verifying the possibility to separate micro-disseminated feebly magnetic minerals with open magnet. The research suggested a new idea about the development of magnetic separator with high efficiency and low costs to separate feebly magnetic minerals and non-magnetic gangues.

Jan 1, 2014