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By Gábor Mucsi, József Faitli, Imre Gombköto, Sanjay Kumar, Zoltán Molnár, Balázs Ráczkevi, Ádám Rácz

"Generally, fly ash particles are very fine (< 100 ?m), mainly spherical and glassy materials form an outer shell on it. This paper deals with the laboratory investigation of ground fly ash based geopolymer. This material can be applied in many fields, mainly in the construction industry, e.g. non-structural elements, concrete, pavements and products, containment and immobilization of toxic, hazardous and radioactive wastes, advanced structural tooling and refractory ceramics, and fire resistant composites used in buildings, etc. The preparation of fly ash using high energy density milling is presented. Systematic experimental series were carried out in order to optimize the preparation process. The particle size distribution (LPSA) and structure of fly ash (FTIR) and the uniaxial compressive strength ,the permeability and structure of geopolymer product, furthermore the rheology of geopolymer paste were investigated. The product properties were studied as a function of the fly ash fineness. As a result of the investigation the relationship between the grinding circumstances, the ground material properties and the geopolymer characteristics was identified. It was found that the above mentioned physical properties of the geopolymer strongly depend on the grinding process."

Jan 1, 2014

By Jan Svoboda, Toyohisa Fujita

The current status and history of innovation in magnetic methods of material treatment are reviewed. The milestones and key drivers of innovation in magnetic separation are identified, advantages of this technology in comparison to other physical methods of material manipulation are discussed and reasons for its failure to live up to its potential and expectations are indicated. Derailers that were responsible for the implementation failures are identified. The future focus in such diverse areas as mineral processing, waste treatment, recycling and biosciences is discussed and the research and development needs are outlined.

Jan 1, 2003

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

By Walter W. Focke, Zola Kwela, Willem van der Merwe, Arao Manhique

"The advantages of the de Wet zirconium process for the manufacture of AZST from zircon sand include: Fewer processing steps; removal of radioactivity by leaching rather than by precipitation; alkali reagent recovery in the form of a sodium silicate solution that is essentially free of radioactivity; fewer waste streams and less waste to discard.Here we report on our efforts at maximizing the alkali recovery in the sodium silicate product stream: Milled zircon, d50 ˜ 9 µm, was fused with caustic soda pearls in open reaction vessels at temperatures between 650°C and 850°C. Fusion times of 1, 2, 4, 24 and 336 hours (with intermittent milling) were investigated.For prolonged fusion times the fusion products approached equilibrium compositions. However, the phases Na2ZrSiO5 and Na4Zr2Si3O12 observed at 850°C did not form at 650°C. Since they do not hydrolyse in water they limit the recovery of alkali. For 2-hour fusions a broad spectrum of non-equilibrium reaction-products, that are rich in sodium silicates, is formed. Optimum process conditions, with respect to NaOH recovery, correspond to a 2:1 stoichiometry and fusing for 2-hour at 850°C. At these conditions the alkali recovery is ca. 78% and the zirconia yield is ca. 57%."

Jan 1, 2003

Electrochemical behaviors of synthetic and natural enargite in buffer solutions have been investigated using open circuit potential, stationary polarization and cyclic voltammetry as functions of solution pH, scan direction, scan range, scan rate and dissolved O2. The results indicate that the electrochemical behaviors of synthetic and natural enargite are very similar; solution pH, scan direction, scan range and scan rate have remarkable effects on the electrochemical behavior of enargite while dissolved O2 has little effect on the electrochemical behavior of enargite. The potential range in which enargite possesses the ability of passivation is from ?0.9 V to + 0.83 V vs. SCE. Enargite is most stable in neutral and alkaline solution around potential ?0.2 V vs. SCE. The main oxidation products on enargite surface in alkaline solution are Cu(OH)2 while the potential imposed on it is within the range of ?0.2 V to 0.33 V vs. SCE and Cu(OH)2 + S0while the potential applied is higher than 0.52 V vs. SCE.

Jan 1, 2014

By Claudio L. Schneider, Reiner Neumann

Any serious study of stereological conversion procedures must be based on an as accurate as possible complete fractionation of a real mineralogical texture. The original work on the Dolomite- Sphalerite Magstream? separation provided excellent data for establishing a working stereological conversion procedure, which has been successfully applied to a number of ores since its implementation. The linear grade distributions measured from these fractionated particles have been published and are accessible. The procedure for stereological conversion from areal measurements is exactly equal to the procedure for linear measurements. Particle composition from the dolomite-sphalerite density-fractionated particle sets, derived from both linear and areal data (Figures 1 and 2, respectively) are redundant, after proper transformation, and match the particle’s compositional range (plotted against S.G.) expected from Magstream?; direct density measurements by Hemicropicnometry plots within the ranges. Linear data cannot be used without conversion, but areal measurements are often directly applied as liberation spectra. Our areal measurements, without stereological conversion (Figure 3), differ completely from the results after transformation, and its density range falls mostly out of the expected/measured values. Therefore non-transformed areal data cannot be directly applied as useful liberation information.

Jan 1, 2003

By Yimin Zhu

This paper introduces the sixteen mappings and rules of mineral flotation and the subgroup, period etc in periodic table of chemical element to provide mineral flotation workers to refer in theory and practice research. the nine mappings and rules of mineral flotation and the subgroup, period are Saline minerals including the first main groups and collectors of aliphatic acid and aliphatic amines, Minerals including the second main group elements and collector of aliphatic acid, Hydrated ion of the second main group elements and quartz flotation, The floatability of oxidized minerals including the four main group elements, Organic acid including the fifth main group elements and wolframe, tin flotation collectors, The floatability of sulfide minerals including the fifth main group elements, Inorganic compounds including the seventh main group elements and mineral flotation regulator, Oxidized minerals including the forth Subgroup elements and organic flotation agents with phosphorus and arsenic, Oxidized minerals including the fifth subgroup elements and organic floating agents including the fifth main group elements, Minerals including the first subgroup elements and CN-, Sulfide minerals including the second subgroup elements and CN-, The effect of the highest N-valency inorganic acids or salts including p area elements of the third period in mineral flotation, Oxidized minerals including transition elements of the forth period and 3# flocculating agent, The floatability of minerals including elements of the sixth period, Element area of generating compositions and the collecting theory of mineral flotation and so and. Keywords: mineral flotation, periodic table of chemical element, subgroup, period, regulator, coordination chemistry

Sep 1, 2012

The status quo of ecological rehabilitation in metal mine in China and progress in the technology for ecological rehabilitation are presented, including soil reconstruction, soil improvement, plant selection. The present and future research fields are suggested: basic theory of ecological rehabilitation, operative technology of ecological rehabilitation, new technology application research and ecological rehabilitation plan, management and policy.

Jan 1, 2014

By Yuexin Han

The wet preconcentration of haematite, comminuted by high-pressure grinding roller was studied, using the cylindrical ferromagnetic medium. The effects of various factors including rod diameter, rod gap and background magnetic field intensity (BMFI) on the performances of preconcentration for different size fractions and the force analysis of single mineral particles with different diameter in the separation zone were emphatically investigated. The results showed that as the rod diameter increased, the rod gap decreased, and the BMFI increased the tailings grade and the tailings yield reduced while the concentrates recovery raised that was regardless of variations in feed size distribution. For the -3.2+0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 7 mm at BMFI of 454kA/m is used to get a higher performance. For -0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 4 mm at BMFI of 263kA/m is used to get a higher performance. After the classifying preconcentration, at the optimum condition, the overall concentrate grade increases by 9.56 percentage points and the concentrate recovery is up to the 82.67% with a tailing grade of 10.68% and a tailing yield of 40.31%. The magnetic force, exerted on weekly magnetic minerals was proportional, to the specific susceptibility and square of BMFI. For the same BMFI, the magnetic capturing force on coarse particles increased, and that on fine particles decreased with the increasing of rod diameter. For the lean locked-particles, considering the gravity and viscous resistance of particles, rods with a big diameter were beneficial to the capture of coarse particles and had no influence on the capture of fine particles, while rods with a small diameter were good for the capture of fine particles and not suitable for the capture of coarse particles of lean locked-particles. Keywords: low grade haematite, high-pressure grinding roller, high intensity magnetic separation, pre-concentration

Sep 1, 2012

By Ana Elisa Casas Botero

The Rhodococcus opacus microorganism was evaluated as a biocollector for flotation of barite. The electrophoretic behaviour of the mineral, before and after R. opacus interaction, was evaluated and showed that the cells adhesion shifted the mineral zeta potential curves. Adhesion tests were suggested a high affinity of the bacteria for barite. The experiments of the adsorption rate of the R. opacus on the mineral surface showed fast kinetics, achieving a maxim of cell adsorption after 5 minutes. Adsorption isotherm curves for barite could be categorized as Langmurian (L) type II. The best bioflotability results for barite achieved values around 75% for a R. opacus concentration of a R. opacus concentration of 250 ppm in the pH around 5.0. The studies were compared with the flotation of barite using a traditional collector. The bioflotation experiments were discussed considering the obtained adhesion tests. The results were supported by the Thermodynamic approach for selected pH values. The fundamental flotation studies showed the paramount potential that R. opacus presents as a biocollector and its possible application in the mineral flotation industry.

Jan 1, 2014

By Vinay Jain, Dharmendr Kumar, Beena Rai, Venugopal Tammishetti

"Selective dispersion-flocculation is considered to be an effective process for the beneficiation of ultrafine particles. This process is based on the preferential adsorption of a flocculant on the mineral particles to be flocculated, leaving rest of the mineral suspended. It has been successfully implemented at plant scales for the beneficiation of ultrafine particles of iron ores, for which conventional methods such as gravity separation, magnetic separation and flotation do not work efficiently. However, the key element responsible for the success of any selective flocculation process is the appropriate choice of the flocculant used for achieving the desired selectivity. At our lab, we are working on design and development of such selective reagents for mineral processing applications, including the beneficiation of iron ore slimes, using a combined molecular modeling and experimental approach. In this study we have employed density functional theory (DFT) to calculate the interaction energies and explain the interaction mechanisms of chitosan with the main minerals present in iron ore slimes, namely, hematite [a-Fe2O3], goethite [a-FeO(OH)], gibbsite [a-Al(OH)3] and kaolinite [Al2Si2O5(OH)4]. The magnitudes of the computed interaction energies follow the trend: Hematite > Goethite > Gibbsite ~ Kaolinite Al-OH terminated > Kaolinite Si-O terminated Analysis of the optimized geometries and electronic structures reveals that the O & N atoms of chitosan molecule form coordinate bonds with surface Fe-atoms of hematite while only weak hydrogen bonds are formed in the case of goethite, gibbsite and kaolinite surfaces thus explaining reasons behind the stronger interactions with the hematite surface. The theoretical findings were validated by performing selective flocculation experiments using chitosan as a flocculant. The selective flocculation experimental results show that a final concentrate of ~60% Fe can be obtained from a feed containing 53.13% Fe with Fe recovery of 74%. The mineral estimation in the obtained concentrate indicated that hematite and goethite are recovered in concentrate while gibbsite and kaolinite are rejected in the tails. These observations were consistent with our theoretical findings. Our work highlights the promising role molecular modeling techniques such as DFT can play in the design and development of selective reagents for beneficiation of alumina-rich iron ore slimes."

Jan 1, 2018

By M. Wierink

The lifecycle of a resource, specifically a metal, is often depicted as circle from primary production from mining to minerals processing and via manufacturing and use to disposal and recycling. When a material is recycled, it is considered as saved energy compared to producing the material from primary source. This is, however, a simplified representation. At each step of the life cycle, there are changes in the quality of the material due to different materials chemical and physical interaction, phase transformations due to diffusion, radiation etc. Due to these physical and chemical phenomena there are losses of material, which as determined by thermodynamics are not recoverable within the life cycle. This can be considered as an increase embodied energy per mass unit of substance and loss exergy from the material cycle. With low cyclic loss, the material will remain in the recycling loop for a long time, while with high cyclic loss it will disappear fast. Where you put the material determines how fast it disappears from the resource cycle. In this research paper the phenomena of quality degradation of material and idea of increase of embodied energy and exergy loss within a resource cycles is portrayed. The cyclic nature of material states and transitions and energy consequences of material quality degradation as well as the parameters affecting the length of the time scales of the material cycles are described. Currently the cyclic embedded energy and the history of material is not taken under consideration in generic life cycle assessment. This easily results into a conclusion that lifetime of product is optimized only in terms of how much energy an appliance uses during its lifetime, while ignoring the loss of embedded energy due to the effects caused by the environs the material is subjected to during the cycle. Better description of the time properties of material give us a possibility to design toward optimum lifetime of products in terms of resource efficiency. Keywords: product lifetime, material lifetime, recycling, cyclic resource efficiency, material state, material quality, exergy, embodied energy

Sep 1, 2012

By M. R. Garmsiri

With the environmental issues and water recycling becoming more significant, the development of deep cone thickeners has improved the efficiency of thickening. While deep cones performance is dependent on many factors, the sensitivity of an industrial thickener to each variable factor has not been determined. In this work, four industrial deep cone thickeners, which are used on tailings stream in Shahrebabak Copper Complex, were monitored for a year to analyze the effectiveness of different factors affecting the performance. Feed flow rate, fine fraction of the feed, solids concentration, flocculant dosage and concentration, solids density, pH, temperature and bed height were the factors investigated on the basis of partial R2 and partial correlation. Results indicated that, with positive effect, feed slurry dilution affected the dewatering efficiency most sensitively. With a negative effect, the sensitivity of dewatering efficiency of deep cone thickeners to flocculant dosage was negligible. While, decreasing flocculant solution concentration had a considerable positive effect.

Sep 1, 2012

By Shailin Lalloo, Allan B. Nesbitt

A fluidised bed was exposed to high gravities by placing it in a centrifuge. The bed expansions were measured and compared with the bed expansions predicted by the Richardson-Zaki model (1954). The Richardson-Zaki model was found to predict effectively the fluidisation behaviour of defined particles in this increased gravity environment.

Jan 1, 2003

By Y. M. Zhu, G. C. Gong

"The influences of citric acid (CA) on the flotation behavior of cassiterite using styrene phosphonic acid (SPA) as the collector were studied via single mineral flotation tests, contact angle measurements, zeta potential determinations and solution chemistry calculations in this paper. The results of single mineral flotation tests revealed under the conditions that pH=4 and the dosage of SPA 100 mg/L, the recovery of cassiterite reached 76.78%. The addition of 20 mg/L AC decreased the recovery by 12.42% at pH=4. Contact angle measurements demonstrated the adsorption of CA prior to SPA made the cassiterite more hydrophilic. The results of zeta potential determinations and solution chemistry calculations indicated the chemisorption of C6H7O7- and C6H6O72- filled parts of the Sn site on cassiterite surface and prevented the SPA from getting adsorbed. The hydrophilic effect of AC was stronger than the hydrophobic effect of SPA and the flotation of cassiterite was crippled. INTRODUCTION Tin is an important metal which is widely used in medical instruments, marine engineering materials, electronic and electrical devices, welding, weapon manufacturing and organotin compounds industries (Angadi et al., 2015). Cassiterite is the only mineral from which the tin can be extracted, thus it is of great importance to efficiently exploit the cassiterite mineral. Flotation is an indispensable method for the recovery of cassiterite (Li et al., 2015). However, cassiterite is usually in association with many other gangue minerals which are of similar floatability, such as quartz, calcite, fluorite, iron oxide, wolframite, scheelite and tourmaline (Sreevinas, 1997). So some modifiers are necessary in the cassiterite flotation process. The amounts of the modifiers used in the flotation must be judicious and the overmuch modifiers may cripple the recovery of cassiterite (Parsonage et al., 1987). Nevertheless, the research about the effects of the modifiers on the flotation behavior of cassiterite has been rarely reported. In this paper, the influences of citric acid (CA) on the flotation of cassiterite using styrene phosphonic acid (SPA) as the collector were investigated by flotation tests, contact angle measurements, zeta potential determinations and solution chemistry calculations."

Jan 1, 2018

By G. Voiloshnikov, A. Bogudlova

"The deleterious effect of carbonaceous matter during cyanidation of gold ores (so called preg-robbing) has been recognized for many years. Based on this, a new method using flotation to reduce the content of carbonaceous matter was developed. Low-sulfide gold-bearing ore with carbonaceous matter of 0.14% from a Russian deposit was processed. The purpose of these tests was to compare two flow sheet options. Option I comprised removal of carbonaceous product prior to sulfide flotation. Option II comprised removal of carbonaceous matter from flotation concentrate. It was found that the content of carbonaceous material can be reduced in sulfide gold-bearing concentrate prior to leaching. High gold recovery was observed during the separation of carbonaceous material prior to sulfide flotation using Option I. Due to lower reagent consumption the costs for reagents were decreased using Option II. The results have shown the effectiveness of a new method. Patent No. 2783808 was obtained for removal of carbonaceous material prior to sulfide flotation. This information will be used to design a large processing plant flow sheet in Russia."

Jan 1, 2014

By L. Rintala

The design of a hydrometallurgical process starts with the analysis of the raw materials to be treated, for example mineralogy, chemistry, deposit size are analysed. Based on this information suitable unit processes for pre-treatment, leaching, solution purification and product recovery are selected. Typically, process design for the new ore deposit relies on laboratory tests such as pre-treatment and leaching experiments. The experimental work is the most time consuming and expensive part of the process design. Reducing the number of experiments would shorten the time of designing a new flowsheet or development of new process technology. A large amount of information is available about the hydrometallurgical experiments and the amount is increasing continuously. For example, word search using ?hydrometallurgy? from Scopus database results in over 4 000 publications with the word in title, abstract or keywords. This number consists of 2 500 articles, 900 conference papers, and 90 reviews since 1972. The number of hydrometallurgical publications per year has increased from 13 in 1972 to 150-200 in the last few years. The objective of this study was to analyze how detailed data of experiments about the gold extraction is published and how that data could be exploited more effectively when designing hydrometallurgical processing for new ore. The leading idea is that similar ores should have the similar response in leaching. If the published information was used more efficiently, the amount of experiments would be reduced. More than 200 cases of experimental data of gold leaching have been analyzed for this study. There are over 30 factors that could be used in comparison when selecting process alternatives, but challenging fact is that not all these factors are documented in all publications. Results show that the usefulness of the published data in the development of hydrometallurgical flow sheet for gold using decision-support tools is not that straightforward. The quality of the published information about gold extraction varied between the publications and the descriptions of the raw materials, experimental arrangements and results were often missing details. Methods to normalize the data for description of the cases and a system to describe different features unambiguously are needed. Keywords: refractory gold, host mineral, leaching, data analysis, case-based reasoning

Sep 1, 2012

By Janne Kauppi, Kaj Jansson, Piia Suvio, Saara Hagnäs

"Historically the focus at the mineral processing sites has been to improve the production operations, while little focus has been set on how factors, such as the quality of water used in the process affects the metal recovery. Simultaneously increasing public pressure and water scarcity is driving the mining industry to recycle more water back to the process, which in turn leads to accumulation of impurities within the recycled water. This paper presents a concept for a systematic approach on targeting the impurities that have a negative effect on the metal recovery at the flotation circuit by using a novel solution called Process Water Recycling Plant (PWRP). These plants are designed with specific ore type in mind. PWRP produces cost-effectively process water to different target qualities, especially for flotation purposes enabling higher and more stable flotation recovery. It consists of pre-designed and standard water treatment units for a wide range of volumes. The application-specific configuration of units is governed by the water quality requirements, and can be designed according to specific customer needs. Testing has been carried out in order to investigate, which recycling water impurities affect the different ore types and how the metal recovery in flotation is affected as a consequence of the poor-quality water. The results indicate that every ore type is impacted differently and without a good understanding on how the water quality impacts the process performance, adverse effects on the flotation recovery can occur.INTRODUCTION With a focus on where water is used within the mineral processing, it has become evident that even though water is used in several different processes, majority of the water losses within the site occur at the tailings processing and the tailings storage facility. New tailings management technologies that can increase the recovery of water are actively being developed, but the key to improving the efficiency of water use and reducing the operational risks lies in closing the water loops and increasing the slurry density in the tailings processing. With this shift from conventional tailings technologies towards paste and dry stacking, water efficiency is vastly improved, but it might in turn lead to process water challenges with impurities, reagents and fines being recycled and accumulated within the production processes."

Jan 1, 2018

By Zhou Junwu, Han Long, Song Zhenguo, Sun Chuanyao

The deposit genesis, the ore property, and the mineral characteristics, which has a close relationship with the beneficiablity, could be regarded as the “Genetic Properties”, actually are the determining factors for beneficiation process development. However, in conventional concentrator’s process development and engineering, there have been lack of systematic research and test on those genetic properties, also lack of well-established collecting, statistics and analysis system for those huge amount of data such as the historical mineral processing technique research, process mineralogy study, practical operating and engineering data. Obviously it is far less than enough for profound integration combining modern IT together with traditional mineral processing technology, as a result there are a number of disadvantages in mineral processing R&D and engineering, such as long term, high cost, low efficiency as well as repetitive testwork not making full advantage of previous experiences. Aiming to make utmost of those Genetic Properties and overcome above disadvantages in mineral processing R&D and engineering, the concept of “Genetic Mineral Processing Engineering (GMPE)” is put forwarded, and the strategical study has been conducted on this regard, with the main focus on following aspects: a) Testing and extraction of the “Genetic Properties”; b) Establishment of data base and data warehouse of GMPE; c) Intelligent decision making system for beneficiation process; d) Verification testwork; e) Virtual concentrator. The technical route proposed is to firstly conduct research and test on those Genetic Properties mentioned above, based on that the specific data base will be set up and applied for intelligent process recommendation and simulation with a few verification testwork conducted in the meantime, finally achieve a fast, high efficiency and precise determination of technology and process for ore beneficiation. The systematic study on the three-in-one GMPE would make an innovative breakthrough in conventional mineral process testwork research and engineering methodology, and provide technical support for the concentrator’s design and upgrading.

Jan 1, 2018

By D. Z. Wang

A red copper plate, discovered in the ruins of Dachengshan in Hebei province, was recognized as a forged one rather than a cast one, which means it was probably made from natural copper during the Longshan Culture period (2200~2208 BC) in the Chinese history. The copperware, found in the Niangniang Tai relics in Wuwei city, Gansu province, contains 99.6% copper and 0.4% Sn, Pb, Sb and Ni, which was guessed to be made during the Qijia Culture about 2000~ 1900 BC in the Chinese history in the late Neolithic before Shang dynasty. This shows that Chinese ancestors were able to distinguish, sort and use some native metals and minerals more than 4000 years ago.

Jan 1, 2014