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By Mohammad Kor, David Beattie, Agnieszka Mierczynksa-Vasilev

The selectivity of polymer adsorption in mixed mineral systems is the basis for polymer depression of gangue minerals in flotation. Effective polymer depressants not only reduce gangue mineral recovery, they also have minimal effect on the recovery of the value phase, presumably through targeted adsorption on the gangue phase, and minimal uptake on the value phase. Traditionally, polymer depressant design has been guided by single mineral phase adsorption tests, with affinity and maximum adsorbed amount determined for gangue and value phases separately. However, there is a need to determine the actual extent of adsorption on the gangue phase while in the presence of the value phase. In this work, we report on the development of in situ atomic force microscopy (AFM) imaging for determination of polymer depressant coverage and morphology on mixed mineral surfaces. Our group has previously used AFM imaging on single minerals to connect adsorbed layer characteristics with bubble-particle attachment and flotation outcomes. Two sample types were used to test the methodology: (i) a mixture of two crushed/ground minerals encased in resin; and (ii) a composite mineral sample containing macroscopic regions of three different mineral phases. The samples have been used to probe the selective uptake of two modified dextrin polymers (octenyl succinate anhydride dextrin). AFM images acquired in situ (while all surfaces are immersed in the same polymer solution) of each mineral phase have revealed the natural selectivity of the polymer for the mineral surfaces. In all cases, the polymers adsorb on the all mineral surfaces present, but to a varying extent.

Jan 1, 2014

By Gianni Shena, Francesco Montanari

"Recent improvements in the resolution of X-ray computed tomography (CT) make it a promising alternative to traditional time consuming, error prone laboratory procedures for mineral liberation analysis, such as heavy liquid fractioning and measurements on polished sections. All indications are that in a few years CT will be well-established in many laboratories as a rapid technique for accurate liberation studies. In this scenario it would be able to provide liberation spectra or washability data in tens of minutes following sampling. However, although CT is a fast evolving technology, its on-line application is unlikely in the foreseeable future.Dual-energy (DE) radiography is another X-ray technique originating from non-destructive evaluation (NDE) and medical fields, which allows retrieval of the volumetric content of valuable components from two-phase particles in a fraction of second. Two radiographic images at different X-ray energies of a single particle or a monolayer of particles are taken in short time sequence. The thickness of the two phases is calculated particle by particle by image subtraction, whereupon particle grades can be derived. The development of the method for on-line applications requires the presentation of non-overlapping particles in the gap in the X-ray source detector measurement couple. Straightforward extension of the principle to multiphase systems is not possible. The paper reviews the state of the art of these two techniques as applied to mineral liberation problems."

Jan 1, 2003

By Y. M. Fu

In order to evaluate the flotation process, the process flow sheet was investigated. The process mineralogy of main products was studied. Through chemical mineralogical and screening analysis as well as surveying using a microscope and scanning electro-microscope, the oxidation degree and mineral composition of main-products the liberation of main minerals, the occurrence of elements such as Pb, Zn were revealed. It is pointed that to determine the flotation process, the type of prod-ucts optimum grind of original ore and middling was provided on the basis of liberation of main minerals is reliable. As correct finer ground original ore, first high-grade lead-concentrates and zinc-concentrates fast was floated from a great part of free of the galena and sphalerite of liberated. Then for finely re-ground middling of locked mineral grains of difficult liberation, mixing lead-zinc-concentrates second was floated. The four products was best in contact with characteristic of ore of Fan Kou. Therefore be obtained certain to successful economic effect.

Jan 1, 2014

By Bharat Garg

The coking coal or clean coal from raw material division, Tata Steel Ltd. is a prime source of energy for inhouse steel making. Coal reserves of semi soft coking coal at West Bokaro is beneficiated by dense media cyclone and froth flotation processes to produce clean coal. In dense media cyclone process two byproducts-middling and rejects are also produced along with clean coal. With the growing demand for clean coal, it becomes imperative to maximize the recovery of clean coal in beneficiation processes. This will help, not only in reduction in cost of production, but also in raw resource conservation, and proper utilization. In this context, a case study was conducted at West Bokaro to identify opportunities for clean coal recovery from by-products. This paper mainly discusses the process for recovery of clean coal from byproducts and study of further liberation of clean coal from byproducts for economic consideration.

Sep 1, 2012

By A. Bastrzyk

Text The mining and refining of minerals generates large amounts of solid waste. The waste from cleaning operations constitutes up to 90% of the total production. Although some of them can be used in mining, civil enegineering, construction, agriculture, most of them must be disposed in dumps and slurry ponds, causing major economic and enviromental problems (Alonso, 2002; Alon-so, 1999). The refuse from minerals cleaning may have considerable valuable particles content, which can be used in industry. Thus, the recovery of these particles from minerals waste by using a cleaning method effective at fine particle size, may overcome these consequences. Surfactants are used in numerous applications including emulsification and solid surface modification. In the oil agglomeration of minerals, the ionic surfactants (both anionic and cationic) are used for the hydrophobization of mineral surface and the oil-water emulsion preparation. When the cationic surfactant is injected into the oil-water mixture, surfactant molecules adsorb at the oil-water interface, changing droplets? properties. The addition of anionic surfactant to the mineral suspension was found to modify the solid-liquid interface. In this paper, the condition and mechanism of selective separation of magnesite from quartz are presented. A satisfactory was achieved with the amount of anionic collector (sodium oleate) equal to 15.2 mg/gsolid and with the amount of cationic collector 27.9 mg/gsolid for cetyltrimethylammonium bromide (CTAB) and 16.9 mg/gsolid for dodecyloammonium hydrochloride (DDAHCl) at pH 8. At these conditions, the amount of agglomerated carbonates was about 12% for CTAB and 5% for DDAHCl.

Jan 1, 2014

By Aidan Giblett, Karen McCaffery, Robert Dunne

"A worldwide decline in competency levels of practicing metallurgists over recent decades has become clearly evident and is a common topic of discussion among senior practitioners and professional associations. The associated impacts on the industry are material and include operational inefficiencies, missed optimisation opportunities and suboptimal new plant designs. There are many contributing factors to this condition. Decrease in competency is particularly evident both in regions where imbalance between supply and demand has led to a general reduction in experience levels for comparable roles over time and in emerging regions where a rapid rise in demand for practitioners has occurred in conjunction with rapid economic development and industrialization. The context, depth and breadth of education curricula and levels vary with location such that solutions to the technical competency dilemma may need to be developed specifically for each region with these influences in mind. Delivering, demonstrating and maintaining competencies are a critical requirement of undergraduate training and ongoing professional development. Other factors such as generational and cultural characteristics and expectations, political influences, role requirements and employment reward and recognition systems all play a critical role in determining if core competencies can be effectively developed, applied and subsequently maintained. This paper reviews factors impacting and some common approaches to competency development. The authors’ experiences in the management of professional development efforts within the global industry are reviewed and a blueprint proposed to address industry requirements in this area."

Jan 1, 2014

By Liu Jin

"In order to reduce the dosage costs and increase the economic benefits of a full floating process in a low grade complex multi-metals W-Mo ore, based on the study of the magnetic characteristics of the main gangue minerals, a joint process by magnetic separation and floatation technology is adopted. The first step of the flowsheet is to recover magnetite by magnetic separation, then remove the magnetic gangues by high gradient magnetic separation (HGMS) and finally recycle the W-Mo from the magnetically separated tailings by flotation. Results of the lab experiment show that in comparison with the full flotation process, the floatation feed tonnage of the combined flowsheet are only 46%. The grade and the recovery of Mo in the rough Mo-Bi concentrate is similar with the original one while the WO3 in the tungsten rough concentrate is increased from 3.85% to 6.64%. The dosage costs are reduced by 53%. The new process can significantly improve the plant economically. INTRODUCTION With the continuous exploitation of scheelite resources, the easily obtained resource is gradually depleting. The ""lean, fine and complex"" scheelite resource has become the main research object of tungsten beneficiation (Lou et al., 2010) (Xiao et al., 2013). The passive situation of tungsten beneficiation can be reversed by enhancing technological innovation and investment in science and technology, changing the business philosophy and mode of production, optimizing the process structure and process conditions, improving various technical indexes and reducing production costs of reagents, which will maximize economic benefits (Jiang et al., 2012 ) (Zhu et al., 2016). A polymetallic deposit of tungsten molybdenum bismuth original process adopts a full flotation process. With the expansion of stope mining, the content of valuable metals in the ore continues to decrease, resulting in a high cost per ton of concentrate produced and a low output value (Li et al., 2015)."

Jan 1, 2018

By M. A. Naimanbayev, Zh. A. Baltabekova, N. G. Lokhova

"Integrated utilization of natural resources using energy-saving and waste-free technologies is relevant around the world. This applies to such type of raw material as titanium-magnetite ore. Shortage of ilmenite raw materials in the Republic of Kazakhstan for titanium slag melting challenges the search of alternative titanium-containing raw materials, titanomagnetites in particular. At the same time there are deposits of indigenous titanomagnetite ores of huge reserves, which can become the complex raw material for production of iron, titanium and vanadium. Tymlay field in the South-Eastern part of Chu-Ili watershed is of particular interest, within the Karasay ore unit with iron content of 30,4 and titanium dioxide - 10%, and after beneficiation titano-magnetite concentrate contains Fe-52,4; TiO2-of 16,06%. Technology of titanium-magnetite concentrate ore-thermal melting was developed at Tymlay deposit producing hot metal and low titanium slag that can become the raw material for titanium production using chloride method. Slag produced in course of titanomagnetite ore-smelting consists mainly of alumosilicates and sodium silico titanates, magnesium and calcium titanates, titanium dioxide and lower titanium oxides. Following operations were carried out to improve titanium slag quality: slag sintering with sodium hydroxide; cake leaching with water to remove water-soluble impurities; to reduce the number of operations impurities leaching with hydrochloric acid was combined with pyrohydrolysis of titanic acid; rutile concentrate production (85% TiO2, 7,66% SiO2), silica removal by means of sodium hydroxide solution treatment, finally sellable rutile concentrate was produced with titanium dioxide 91-92% and silica 1,7 to 2,0% content. Based on research results technological scheme of titano-magnetite concentrate processing at Tymlay deposit was proposed producing hot metal and certified rutile concentrate, suitable for chlorination."

Jan 1, 2018

"A sulfide ore containing 2.19 g/t Au and 13.13 g/t Ag was studied for the deportment and extractive metallurgy of pay metals. The ore is composed mainly of non-sulfide minerals with approximately 10% pyrite and minor amounts of marcasite, chalcopyrite, galena, sphalerite, and arsenopyrite. The deportment study using a comprehensive approach showed that gold and silver minerals in the ore are mainly native gold (Au), electrum (Ag, Au), petzite (Ag3AuTe2), hessite (Ag2Te) and volynskite (AgBiTe2) with minor amounts of acanthite (Ag2S) and argyrodite (Ag8GeS6). At current grinding fineness (P70@150µm), the majority of liberated native gold and electrum particles are larger than 20µm with 85% >40µm, some of them are even larger than 150µm, indicating that extended leach time may be required to dissolve these coarse gold grains to completion and gravity concentration needs to be considered. Petzite is relatively fine with all liberated particles being less than 80µm in size. Gold distribution and leach testwork results showed that liberated gold accounts for 50% of the head assay, exposed gold associated with sulfide and non-sulfide minerals accounts for 30% and 11% of the head assay, respectively. Gold locked in sulfide and non-sulfide accounts for 4.8% and 4.1%, respectively. Thus, it is recommended that cyanide leaching be considered for extracting gold in this ore. This paper presents the detailed results of the gold and silver deportment study and extractive metallurgy testwork, and discusses the impact on process selection and flowsheet development.INTRODUCTION Gold and silver have been found in various geological environments and ore types. In terms of the gold deportment and extractability, gold ores can be classified into two categories and 12 types. Their extractive metallurgy is largely driven by mineralogical factors such as particle size, association with other minerals, coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of refractory gold minerals and locking of submicroscopic gold in sulfide and sulfarsenide mineral structures (Zhou et al., 2004; Marsden & House, 2006; Zhou, 2013a, 2013b). Compared to gold, silver mineralogy is more complex and metal extraction is more challenging due to its presence in over 200 Ag-bearing minerals (a silver-rich ore body would typically contain 5 to 10 different silver minerals) (Gasparrini, 1984), presence of refractory silver minerals (such as pyrargyrite, prustite and stephanite) and submicroscopic silver in sulphide minerals (such as galena and copper minerals) (Chryssoulis et al., 1985; Di Prisco et al., 2002). The presence of these issues often causes problems in Ag-bearing ore processing. Therefore, knowing the deportment of gold and silver in the ores and metallurgical products is important for flowsheet development and process optimization."

Jan 1, 2018

By Junwei Han, Kai Xue, Wenqing Qin, Tan Xu, Fen Jiao, Lianbing Cai, Wei Liu

"The research aimed at solving the problem of the stacked spent magnesia-chrome refractories using in non-ferrous metal smelters, which contain various heavy metals and are considered as a hazardous waste. The purpose of the research is to recycle the spent refractories environmentally and economically using gravity separation and flotation to obtain metal concentrates for smelting and using chloridizing volatilization to remove the trace metals from tailings, providing raw material to reprocess magnesia-chrome refractories. In the course of the study, laboratory techniques for the preparation of experimental samples of spent magnesia-chrome refractories were developed including the sequence of operations of material grinding, gravity separation, tails regrinding, flotation, filtration and subsequent unification of concentrates, filtration and chloridizing volatilization of tails, and collection of volatiles. Laboratory tests carried out on several types of samples of spent magnesia-chrome refractories from different smelters showed that gravity separation provided increase in quality of concentrates including about 80% metals (including Ag, Pb, Bi) and flotation separation provided increase in recovery of concentrates under the condition of 200g/t of emulsified kerosene, and 500g/t of combined collector. Based on combined technology of gravity and flotation separation, about 90% metals were recovered from the refractories by a closed-circuit test and the total concentrates contained 40% metals, which can be returned to smelting process as a feeding. Because a small amount of metal in raw materials will seriously affect the performance of refractories, chloridizing volatilization is necessary for removing the remaining 10% metals from tails mixed 8% coke and 13% magnesium chloride at a temperature of 1200°C. Thus, the tailings can be reused as a raw material for new refractories.INTRODUCTION Magnesia-chrome refractory has been used extensively in various industries such as secondary metallurgy, non-ferrous furnaces and cement making due to their high temperature stability, low thermal expansion and outstanding erosion-corrosion performance at high temperatures (Gotod et al., 2005; Vezza et al., 1997; Gregurek et al., 2015). Generally, the magnesia-chrome refractories are produced from a mixture of magnesia and massive variety of chrome ores. However, massive chrome ores are being depleted throughout the world. Even more serious is that the heavy metal chromium (Cr) can transfer into soil and water, which will have an influence on the survival and development of human beings (Zhao et al., 2006; Jiang et al., 2004; Qintie et al., 2013). As a result, regulations treating spent magnesia-chrome refractories as potentially hazardous waste are being enforced, making their disposal difficult and expensive."

Jan 1, 2018

By V. A. Luganov

The processing of pyrite concentrates may be accomplished with a preliminary enrichment due to withdrawal of iron sulfides from initial concentrate. The withdrawal of iron sulfides is possible with the help of magnetic separation when the magnetic iron sulfides (pyrrhotites) separate from non-magnetic fraction?the sulfides of non-ferrous metals. The conversion of non-magnetic pyrite to magnetic pyrrhotites of adjusted structure occurs because of roasting with the withdrawal a part of sulfur. The resultant pyrrhotites are strong ferromagnetic with hexagonal structure. This paper contains results of studying magnetic properties of pyrrhotites, findings of the de-composition of initial pyrite with the consequence homogenizing of product and hardening of product of decomposition in liquid nitrogen. Define the type of pyrrhotites super lattice structure, was established that at increasing of sulfur contention the magnetic properties of pyrrhotites are change ? pyrrhotite begin evince the properties of antiferromagnetic material and magnetic susceptibility of material is interruptive changing from 0 to 1.7×10-3~1.9×10-3 SI units/g system. The paper contains results of technological researching of pyrrhotizing-magnetizing roasting of pyrite concentrates in different condition: in unoxidizing, with the decreasing contention of oxygen and in autogenous regime in air atmosphere. Established that the magnetic susceptibility of products depend of pyrite degree dissociation and achieve 2×10-3~3×10-3 SI units/g system at 40%~45% desulphurization. Defined the conditions of steady regime autogenous roasting, at resultant products possess coefficient of magnetization, and this can be used magnetic separation for separating ferromagnetic pyrrhotites from gangues and non-magnetic sulfides of non-ferrous metals. This technology of pyrrhotizing roasting is recommended for effecting in industrial condition. The initial materials and products of roasting subjected to chemical, thermogravimetric, Moss-bauer spectroscopy and X-ray analysis, defined the magnetic properties.

Jan 1, 2014

By S. K. Dutta

Enormous amount of iron ore fines is generated, due to partly soft and friable nature, during mining. Coal fines are also produced during their processing. These fines cannot be used directly in ironmaking reactors. Utilization of these fines for extracting metal is of vital concern for resource conservation and pollution control, and therefore, a novel concept of agglomeration by cold-bonding is developed. Composite briquettes/pellets of iron ore fines with coal fines were prepared in the laboratory by cold-bonding technique. Various binders such as lime, Ca(OH)2, slaked lime, dextrin, molasses, fly ash etc were employed either alone or in combination in different proportions for making composite briquettes/pellets. It was possible to obtain dry strength of composite briquettes more than 300 N/briquette in some cases and more than 200 N/briquette in many trials. The combination of fly ash with slaked lime and molasses produced the highest strength, more than 400 N/briquette. Drop strength and shatter index values of composite briquettes/pellets were also measured. In briquettes, best compressive strength (978 N/briquette) is observed by using polyvinyl alcohol (PVA) binder. In pellet, best compressive strength (362 N/pellet) is achieved by PVA; shatter index (0.1%) and dry drop strength (158 numbers) are also good. Compressive strength above 200 N/pellet is obtained by fly ash, slaked lime and molasses combination.

Sep 1, 2012

By Pengbo Chu, James Finch

Bubbles around 1 mm diameter provide the high interfacial area for capture and transport of hydrophobic particles in flotation. The formation of such fine bubbles is commonly achieved by addition of frothers that appear to simultaneously retard coalescence and promote break-up. High inorganic salt content in process water can substitute for frother. In this work we focus on the action of salt (sodium chloride) on formation of bubbles by break-up. An experimental setup that isolates break-up from coalescence was employed. A pocket of air is exposed to controlled mechanical turbulence to produce single bubbles by the induced deformation of the air and the events imaged. The presence of salt is shown to produce smaller bubbles than in water alone. Comparison with a similar study on frothers is made. The argument is advanced that the presence of frother and salt creates surface tension gradients at the air/water interface which add to the mechanical energy of the deformation and break-up process.

Jan 1, 2014

By I. A. Khabarova

The paper presents the results of experimental investigations of the effect by high-power nano-second electromagnetic pulses (HPEMP) on change of surface composition, physical-chemical and flotation properties of pyrrhotite, and search of optimal combination of flotation reactants providing increase of metal extraction from disseminated copper-nickel ores. Preliminary electropulse effect on products before flotation allows to create optimal conditions for flotation separation of pentlandite and pyrrhotite owing to forming the new phases and defects on the surface of sulphides. It was established, that the yield of monomineral fractions of pyrite, pyrrhotite and chalkopyrite increases by 5%~15 %, compared with flotation with one butyl xanthenes (BX), during usage of combination of thionic carbamate (isopropylmethylthionocarbamate (ITC) or isopropylethyl- thionocarbamate (Z-200) with butyl xanthate (BX). Sorption of investigated reactants and strength of their fixing on the surface of minerals are examined; it helped to reveal the cause of rise of floatability of sulphide minerals for the case of combination of reactants. Preliminary high-pulse processing and reactant conditions with usage of combination of thionic carbamate and xanthate have been tested on the sample of disseminated copper-nickel ore from Norilsk region.

Jan 1, 2014

By Rodney J. Hundermark, Sharif Jahanshahi, Shouyi Sun

"The major platinum producers in South Africa make use of electric furnaces for the melting of PGM bearing nickel - copper concentrates. To gain better understanding of the furnace operation, research was conducted at CSIRO Minerals in Melbourne, Australia. One aspect of the research project was the investigation of the factors affecting the electrical conductivity of melter type slags.Electrical conduction in slags can occur through two mechanisms: ionic and electronic. There is good understanding of the ionic mechanism. In slags containing high levels of iron, the dominant mechanism is electronic. There is limited understanding of the electronic mechanism and one of the aims of the research was to investigate this mechanism further.Experimental work was carried out on Al2O3.CaO.FeOx.MgO.SiO2 slags similar in composition to the melter slags. Conductivity increased significantly with iron oxide content. Above 20wt% FeOx, electronic conduction was significant and the conductivity varied with the oxidation state of the slag. As the iron oxide content was increased further, the electronic mechanism became more dominant. The conductivity reached a maximum at around pO2 = 10-7 to 10-4 atm., although this value was dependent on the total iron oxide content and basicity of the slag."

Jan 1, 2003

By Q. Cui, Z. G. Song, S. S. Lin, S. Q. Li, S. S. Lu, G. B. Zheng, A. J. Ren

"Mine tailings is one of the most important bulk industrial solid wastes, but its rate of comprehensive utilization is relatively low. Efficient separation, recovery and utilization of the valuable components is one focus of the comprehensive utilization of tailings. Beneficiation recovery of the valuable minerals is the most direct comprehensive utilization method for tailings. There are generally different kinds of nonmetallic minerals contained in the nonferrous metal mine tailings, which are secondary mineral resources waiting for further developing and recovery. Comprehensive utilization test studies on fluorite in tungsten beneficiation tailings and feldspar in molybdenum beneficiation tailings have been carried out by author and good test results are achieved. Some of the technologies developed in the test study have been applied in industrial productions, which have been working well. The economic, social and environmental benefits are remarkable. Our test studies and some production practices will be summarized and current situation and existing problems of comprehensive utilization for nonferrous metal mine tailings will also be discussed. Assumption and prospect for the future study on comprehensive utilization of nonferrous metal mine tailings will be brought at last.INTRODUCTION Mine tailings is one of the most important bulk industrial solid wastes, but its rate of comprehensive utilization is relatively low. Efficient separation, recovery and utilization of the valuable components is one focus of the comprehensive utilization of tailings. Beneficiation recovery of the valuable minerals is the most direct comprehensive utilization method for tailings. There are generally different kinds of nonmetallic minerals contained in the nonferrous metal mine tailings, which are secondary mineral resources waiting for further developing and recovery. Comprehensive utilization of nonmetallic minerals of nonferrous metal mine tailings not only can improve the value of the ore but also reduce the stock of tailings, being the key to reduce emissions at source for exploitation of nonferrous mineral resources (Cai, Yang, 2000)."

Jan 1, 2018

By Sanjay Chaudhuri, V. K. Kalyani, Pradeep Kumar Singh, T. Gouri Charan

"Indian coal industry is the world's third largest in terms of production and fourth largest in terms of proven coal resources. Indian coal deposits are generally of high ash content varying from 24 to 50%. The coking coal reserves of India constitute about 12% of the total coal inventory, and the coals are washed in washeries, before being used for metallurgical purposes. The processes used for washing coking coal is Jigs, Heavy medium bath and Cyclones for the sizes upto 0.5mm, while the coal fines are washed in spirals and conventional flotation cells. Extensive studies were carried out for understanding the performance of an operating conventional flotation plant. The performance studies revealed that appreciable quantity of clean coal is being lost in the tailings due to varied reasons and the required quantity and quality was not achieved. In this study, laboratory Flotation experiments were carried out to examine the cleaning characteristics of the said tailing and to determine the effective process parameters for recovery of clean coal at desired ash level ( 16-17%). Response Surface Methodology was applied to investigate the operating conditions of the Froth Flotation for modeling and optimization. Primary study reflects that there is a possibility to recover clean coal at 16-17% ash level with a yield of about 60-70% from that Flotation tailing of feed ash about 28%.INTRODUCTIONMost of the Indian coking coals are difficult in cleaning characteristics and high ash content due to its drift origin and its age of formation for more than 225 million years. Indian coking coal reserve is limited about 12% of total coal reserve. The minerals are homogeneously mixed with the coal macerals. The open cast mining practice and mechanized mining methods are being adopted to meet the increasing demands of coals resulting in generation of more coal fines and subsequently the quality is deteriorated. Indian good quality coking coal reserves of higher seams are fast depleting and hence coking coals of difficult cleaning characteristics of lower seams (LVC) are being now explored. Due to increased mechanization of coal mines to cope up the increased demand and followed by size reduction of lower seam coals in search of better liberation , the coal fines are increasing by leaps and bounds. The processes used for washing coking coal is Jigs, Heavy medium bath and Cyclones for the sizes upto 0.5mm, while the coal fines are washed in spirals and conventional flotation cells."

Jan 1, 2018

By A. V. Golovanov, A. V. Mihailova

"NPO RIVS employs complex approach to engineering and design of the new facilities in close cooperation of Mining, Research, Hydrometallurgy, Design, Construction, Power Supply, Automation, Production and other departments. General Design Contractor (and then General Contractor) is directly involved in geological exploration, engineering surveys, floatability studies, feasibility study of process solutions and construction options. It delivers greenfield project and guarantee its efficient performance in future. Shiralgin is a small gold and copper deposit, gold average grade is 4.7 g/t. RIVS departments have studied ore floatability, developed process procedures for design and performed pilot testing. Construction of integrated plant including ore crushing and grinding, flotation and hydrometallurgy units with Dore gold production of 5 000 thousand tons ore per year (66.7 t/h) is recognized as economically viable. The technology used of separate dry stockpiling of flotation tailings and cyanidation tailings. Water circuit for concentration and hydrometallurgy is separated, too. Process design was performed based on BIM software like Autodesk Revit, Civil 3D, Rocscience slide using process procedures developed by RIVS Research units. Engineers provided modeling of primary crushing unit, coarse ore storage, main building (including grinding, flotation, thickening, filtration, loading, hydrometallurgy), tailings thickening unit, building for reagent storage and conditioning, tailings pond for dry stockpiling of flotation tailings and cyanidation tailings, sedimentation ponds, laboratories, infrastructure including Administration building and camp. Payback period is 3.5 years. 3D model of facility is currently stored at the State Agency of Geology and Mineral Resources affiliated to the Government of the Kyrgyz Republic.INTRODUCTION The Kyrgyz Republic has substantial potential of mineral resources including gold ores. Mining industry actively develops and involves international investors. Inventory includes 42 deposits (Figure 1) that have reserves of 616.4 t [1] of gold. The Kyrgyz Republic takes the third place in gold mining among CIS countries after Russia and Uzbekistan by producing up to 20 t annually."

Jan 1, 2018

By Kevin Galvin, Simon Iveson

Fine particles are the most valuable because they are the most liberated. However, they are also the most expensive and difficult to recover and concentrate. The Reflux Classifier is a novel invention that combines many of the virtues of existing fine particle separation technologies in a way that provides profound synergies. Multiple parallel narrow channels create a laminar-shear separation zone. The laminar flow provides a well-defined velocity gradient that exposes particles on the wall to a conveying velocity that is approximately proportional to their size, thus reducing the dependence of elutriation velocity on particle size. The high shear rate in these channels generates a hydrodynamic lift force that selectively lifts low-density particles off the channel wall and thus causes them to be preferentially conveyed out in the overflow. Particles that are not elutriated slide back down into the mixing reflux zone beneath the inclined channels which gives them multiple opportunities to re-enter the channels. The resultant suspension of both coarse and fine high-density particles in the fluidized bed zone at the base of the unit generates a strong autogenous dense medium that helps to direct large low-density particles back up to the overflow. The fluidization water also simultaneously de-slimes the high density underflow product. When placed in a centrifuge, the benefits of these features multiply with the improvements in capacity and selectivity that arise from high G-forces. When inverted, these features can be used to perform flotation well beyond the conventional flooding limit. Hence this invention platform has the potential to dramatically improve both gravity and flotation separation performance across the minerals processing industry.

Jan 1, 2014

By R. Shiva Kumar, G. E. Sreedhar, Rajan Kumar, K. Suresh, A. K. Aketi Veera, M. Narasimha, P. S. Jodan

"In most of the coal washeries, Dense Medium Cyclone’s (DMC) are deployed to treat coarse coal fraction in the range of 50-0.5 mm. DMC’s are very popular due to its ability of high tonnage, ease of operation and effective separation at high near-gravity material (NGM) in feed coal. The ease or difficulty of washing is merely depending on the NGM fraction present in run of mine coal. However, the quantitative effect of NGM on DMC performance was not explored in the literature. Hence, in this investigation, the influence of NGM on DMC performance is focused. With the help of synthetically prepared coal mixture, the effect of NGM mass fraction on separation efficiency is studied in three different approaches. Firstly, by increasing the NGM coal fraction systematically from low to as high as possible; second by varying the distribution of NGM coal; and third by varying distribution of particles lying just above and below the near-gravity zone. Washability studies are also carried out to establish the theoretical yield for the prepared synthetic mixtures. Pilot-plant experiments are carried out in a 4-inch DMC with 1.4 operating separation density treating coal in the size range of 4 - 0.5 mm. From results, the partition curves are constructed by both density and size wise distributions. It is observed that at higher NGM coal fraction i.e above 60%, the performance of DMC is very poor with significant coal particles misplacement. In second approach with increased distribution at higher density fractions, the separation efficiency reduces. In third series the distribution of fraction in near-gravity zone doesn’t much effect the separation except the shift in separation density. It is observed that smaller size (-0.5 mm) coal particle having high NGM content seems have a profound effect on DMC performance leading to significant fines misplacement to wrong products."

Jan 1, 2018