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By Kazutoshi Haga, Batnasan Altansukh, Shirchinnamjil Nyamdelger, Atsushi Shibayama, Narankhuu Ariunbolor, Gunchin Burmaa

In this study, the authors investigated the capability of an acidic thiourea solution and silicon-organic polymers (PSTM-3c, PSTM-3T) as ion-exchange resins to recover of gold from gold-bearing ore concentrates. Firstly, elemental gold present in flotation concentrates was dissolved by leaching with a solution of nitric acid and thiourea under the optimized conditions. The best result on gold thiourea leaching was obtained under a nitric acid concentration of 2 N, thiourea concentration of 2 %, and oxidant (Fe2(SO4)3) concentration of 3 %, solid:liquid ratio (S:L) of 1:20, leaching time of 6 hours at 20 °C with a gold recovery of 93.7 % for a gold flotation (unroasted) concentrate. For the roasted gold concentrate, the dissolution of gold was 94.8% under the optimized leaching condition as nitric acid concentration of 0.5 N, thiourea concentration of 2 %, and the oxidant concentration of 1 %, S:L ratio of 1:10, leaching time of 4 hours at 50 °C. Secondly, a series of sorption tests was carried out on a pregnant leach solution containing gold complex Au[S=C(NH2)2]2+ using silicon-organic polymers (PSTM-3c and PSTM-3T), respectively. The effects of solution pH, adsorption time and temperature in the sorption process are also studied. As the results, the PSTM-3c and PSTM-3T polymers were adsorbed about 94.4 % and 95.1 % gold from the pregnant leach solutions under the optimum sorption conditions, respectively. It was found that the both PSTM-3c and PSTM-3T polymers were effective for the recovery of gold from the pregnant leach solution of thiourea. Adsorption activity of the PSTM-3c and PSTM-3T polymers was confirmed by new peaks near 1700 cm-1 in the FT-IR spectrum of the gold-adsorbed polymers, respectively.

Jan 1, 2014

By P. Huang, D. W. Fuerstenau

Various factors that control the natural flotability of talc, including differences due to crystal face and edge effects, were delineated. For study of talc depression phenomena, dextrin was used as a model depressant. For the enhancement of talc flotation, dodecylammonium acetate (DDAA) was used as the collector. The interaction of DDAA with talc was assessed by flotation experiments and electrokinetic (zeta potential) measurements, from which the role of hydrophobic bonding can be demonstrated. The results presented in this paper provide useful information on how the crystal chemistry and surface chemistry control the electrical double layer, adsorption phenomena, wettability, and flotation behavior of talc in aqueous media.

Jan 1, 2003

By Markus A. Reuter, Joep Verwoerd, Marc J. A. Pijnenborg, Yongxiang Yang

"Incineration is a proven disposal technology for all waste materials with heat release potentials, and provides high degree of toxic destruction and control for a broad range of hazardous materials. In the Netherlands, all the hazardous wastes are processed at AVR-Chemie located at the Rotterdam harbour, through rotary kiln incinerators. The newly enforced regulations from the European Union with stricter emission levels require a better understanding of the incineration process and improved process control. However, the transport phenomena and combustion processes within the kiln system are very complex and not well understood. In order to get better understanding of the incineration process, research has been carried out to study the fluid flow and combustion behaviour of the incineration system. Computational Fluid-dynamics (CFD) was used to simulate the gas flow and waste combustion process, and temperature measurements of the operating rotary kiln incinerator were conducted to validate the CFD model. This paper will present the latest results from the current research project for simulating gas flow and combustion heat transfer for a wide range of hazardous waste streams.The simulation of the waste incineration process was carried out using a general-purpose CFD code Phoenics. The rotary kiln and the secondary combustion chamber (SCC), with a waste processing capacity of 50,000 ton/y and an energy input of 30 – 40 MW, is translated into a CFD model. The model includes a k-e turbulence model and a global gas-phase combustion model (3-gas or 7-gas combustion model). The 3- gas model (Simple Chemically-Reacting System, SCRS) predicts only the thermal effect of the fuel combustion, and only one global fuel is used, therefore, real chemical species are not taken into account. In the 7-gas combustion model, (an Extended SCRS, ESCRS), different forms of waste fed into the incinerator have been modelled into a mixture of a general hydrocarbon fuel C3H4 and other components such as CO, CO2 and H2O. Thus, all the incoming fuel streams with different compositions and calorific values can be properly converted into separate inlets. The combustion of the waste is assumed to take place only in gas phase in two steps: (1) primary combustion of the main fuel component C3H4 to form CO and H2, (2) secondary combustion of CO and H2O to form CO2 and H2O. The rate of each combustion reaction is assumed to be controlled by turbulent mixing of fuel and oxidant (air or oxygen), i.e. the Eddy-Break-up (EBU) model. The resulted temperature field was validated with temperature measurement data, and the simulated temperature distribution from both 3-gas and 7-gas model have reasonable agreement with the measured data."

Jan 1, 2003

By Yuhua Wang, Haitao Zheng, Guangli Zhu, Yuehao Zhao, Fushun Yu, Dongfang Lu

"Spodumene, feldspar and quartz possess similar surface properties, which make the difficult to separate spodumene from other silicate minerals by flotation. The differences of crystal structure, surface property and floatability of three minerals were studied by various technical means. The results show that Li-O and Al-O bonds in spodumene structure are not strong and easy to be broken. However, Al-O and Si-O bonds in feldspar and Si-O bond in quartz are very strong and not easy to be broken. High contents of Al and Li on spodumene surface were found by XPS measurements, which is benefit for the adsorption of anionic collector. The surface energies of main cleavage planes of spodumene (110), feldspar (001) and quartz (001) are 1.88 J/m2, 2.97J/m2 and 2.68J/m2, respectively. Hence, the exposed surfaces of feldspar and quartz are not saturated and easy to adsorb OH- ions from solution and cause the lower IEP than spodumene. The contact angles of three minerals in water are lower than 16º, suggesting that the hydrophilicity of three minerals is high, and the order of hydrophilicity is quartz > feldspar >spodumene. Correspondingly, contact angles and flotation recoveries of spodumene are bigger than that of feldspar and quartz in presence of a combined anionic and cationic collector named YOA.INTRODUCTION Flotation technology plays most important role for the recovery of spodumene from pegmatite ore. Generally, spodumene with fresh surface is easy to be floated using soap and oleic acid as collector, and the best flotation pH range is 4.0 to 9.0. However, the flotability of spodumene will become worse when its surface was polluted by slime which produced by the weathering of spodumene and other silicates (Dresler et al. 1998; Moon and Fuerstenau 2003; Menéndez et al. 2004; Yu et al. 2015). In addition, the species of Ca2+, Fe3+, Mg2+ and other metal ions in pulp can not only activate the flotation of spodumene, but also the activation of gangue minerals, and then the flotation selectivity of spodumene from gangue minerals became wores (Wang and Yu 2007; Yu et al. 2014). In order to eliminate the negative effects of slime and metal ions on the flotation of spoddumene, the desliming and long time scrubbing with the addition of NaOH and Na2CO3 were adopted. Usually, NaOH shows the activation for spodumene flotation, and the recovery of spodumene increases with the increase of NaOH dosage. Na2CO3 can eliminate the non selective activation of Ca2+, Fe3+, Mg2+ ions in the pulp, and the concentrate grade of spodumene increases with the increase of Na2CO3 dosage. Anionic collectors such as chelants, hydroxamic acid, oxidized paraffin soap, naphthenic acid and oleic acid were widely used for the flotation of spodumene (Dresler et al. 1998; Moon and Fuerstenau 2003; Menéndez et al. 2004; Yu et al. 2015)."

Jan 1, 2018

By Liu Xinghua

Yuanjiacun iron ore located in Shanxi province of China has finely disseminated grain size and contains refractory iron-bearing silicate gangue minerals such as chlorite. Therefore, a large amount of secondary slime (the content of -10µm fraction was up to 32.92%) was produced inevitably in fine grinding process, and chlorite was also enriched in concentrate from the content of 4.3% to 14.8% after high intensity magnetic separation. These two characteristics result in the difficulty to deal with Yuanjiacun iron ore by flotation. In this test work, contrast tests between single reverse flotation and selective flocculation desliming-reverse flotation were conducted on Yuanjiacun iron ore. The test results show that after selective flocculation desliming, the iron grade of cationic reverse flotation concentrate increases by 6.15% and the recovery increases by 7.25%; the iron grade of anionic reverse flotation concentrate also increases by 2.15%. Furthermore, analyses of grain size composition and mineral composition were carried out on separation products, the results indicate that selective flocculation desliming plays a dual role of optimizing grain size composition of flotation feed and removing iron-bearing silicate gangue minerals (chlorite) effectively.

Sep 1, 2012

By Y. De Gao, C. Gang Zhong, X. Yang Qiu, Li Wan

The chelating reagents are used as effective collectors in wolframite flotation, and certain metal cations need to be added using chelating collectors so as to activate valuable minerals and obtain good flotation indexes. Different metal cations will result in different reactivity with collectors, in order to select the effective activator in BHA flotation of wolframite, the activation effectiveness of different metal cations on wolframite ((Fe,Mn)WO4) flotation were studied using pure minerals. The results showed that the wolframite activation by Pb2+was the best among the selected cations. The maximum flotation recovery of wolframite was found to be 95.58 % under conditions of 100mg/LBHA and 1×10-4mol/L of Pb2+at pH 9. The dosage of Pb2+needs to be controlled in an optimum range. Also, the activation mechanism of Pb2+ on BHA flotation of wolframite was investigated by measurements of contact angle, zeta potential, adsorption capacity and IR spectroscopy. It was found that Pb2+ could chemically adsorb onto the wolframite surface improving the flotability of wolframite and enhancing the adsorption of BHA on wolframite. When the dosages of BHA and Pb2+ were 100 mg/L and 1×10-4 mol/L, the adsorption quantity of BHA on wolframite sharply increased up to 0.30 mg/L at pH 9 compared with wolframite treated with only BHA.

Jan 1, 2014

The simulation study on the process of iron ore beneficiation plant of Essar Steel, Kirandul was carried out. The iron ore fines and slimes generated nearby Bailadila mines of NMDC are used as raw materials for this beneficiation plant. The capacity of the plant is 1400 TPH operating in parallel in two streams. The capacity of the plant was utilized about 60% of throughput capacity. To improve the plant capacity as well as quality performance, the simulation study was conducted to detect the bottleneck of the process. The process samples were collected from input and output of each processing unit operation to generate the data base for simulation study at the feed rate of 400 and 500 TPH of iron ore fines in a single stream. The characteristics data i.e., breakage and selection functions were generated using MILLSOFT package for simulation of ball mills. Then MODSIM package was used to evaluate the performance of each unit operation to identify the bottleneck. It was established by a simulation study that the intermediate thickener draws high current when the feed rate is more than 400 TPH due to high torque drawn by rotating rake because of presence of coarse particles in the input stream to thickener. The problem was sorted out by classification of input stream of thickener to remove the coarse particles. Then the process was simulated at its rated capacity, and experimental validation studies at the plant were also conducted at the feed capacity of 600 and 700 TPH by modification of process flowsheet. The experimental data was almost matching with simulated data. Finally, the processing plant is running with full rated capacity without any bottleneck. Keywords: simulation of ball mill, breakage function, selection function, iron ore

Sep 1, 2012

By C. B. Wu

This paper presents an analysis of comminution behavior of using cast iron segment (CIS) as fine grinding media with comparison to conventional steel ball. Grinding experiments utilize just one-size medium and mixed size media in laboratory were carried out and its efficiency is expected to be improved. The results show that no matter whether one-size medium or mixed size media employed, grinding efficiency of CIS media can be considerably equal to that of steel ball, on the other hand, grinding product by two kinds of media can conform to Robin-Rammler?s size characteristic curve and distribute in function of . )exp(100nbxy-= Comparing with steel ball, the milling capacity with CIS media could be increased up to about 8.6 percent, overcomminution decreased 3.96 in percentage and qualified size increased 3.98 in percentage in case of grinding fineness retained. At the same time, due to the improvement of grinding product size characteristic and its metal distribution characteristic, the grade and recovery of easy to separation size increased 0.24 in percentage and 6.47 in percentage respectively. Based on these results, the CIS media can be employed as novel fine medium for grinding process substituting for steel ball.

Jan 1, 2014

By R. Hejazi, Saghaeian. M., H. Abedini

Continuous vacuum belt filters mainly carry out an important duty in the solid-liquid separation processes such as iron ore concentrate dewatering. However as the particles become finer, the resistance to filtration and dewatering would increase and as the result cake moisture content tends to increase. So in recent decades, using additives in order to improve the filtration performance has been considered by many researchers. In the present study, the effect of several surfactants on the filtration rate and cake moisture content of Chadormalu iron ore concentrate (80% =40 micron) was investigated using a laboratory scale vacuum filter. The results of several tests indicated that a non-ionic surfactant (Lauryl Alcohol Ethoxylated, LAE) has the best performance on reducing the moisture content of the cake and reducing the cake formation time. The optimum dose of LAE was found to be 300 g/ton which reduced the concentrate cake moisture content from 13.76 to 11.28% (wet weight base). Some industrial filtration tests were performed in Chadormalu iron ore concentrate plant to prove the effectiveness of this surfactant. The surfactant is mixed with water and added to the concentrate slurry before distributing on the vacuum belt filter. The industrial and experimental results were almost similar, so that adding about 300 g/ton of LAE would reduce the final cake moisture content from 12.87 to 10.76%.

Jan 1, 2014

By Fedotov. K. V., A. Y. Senchenko, V. A. Chanturiya

"The paper describes an efficient process to treat the ore from the largest in Russia copper deposit – Udokan. The recommended process is universally applicable to Udokan ores different in composition and allows reaching high copper recoveries during production of high-grade cathode copper and sulphide concentrate with 45% copper content. There are several promising trends for the process optimization and in the case they are implemented, economics of the whole project could improve significantly. One of the most important optimization options implies reduction of specific energy consumption in the course of comminution operations. Another possible option to optimize the already selected process flowsheet is production of cathode copper from sulphide concentrate directly at a mining and metallurgical plant without sending the latter to other metallurgical works.INTRODUCTIONUdokan copper deposit with resources of more than 20 million tons of copper is the largest in Russia and one of the largest copper deposits in the world. The deposit is located in Kalar District of the Trans-Baikal Territory, 30 km away from Novaya Chara railway station of the Baikal-Amur Mainline.Scientists and engineers from various research institutions have studied Udokan copper ores for years. Along the way, some conceptual process flowsheets have been proposed and each of them has its own pros and cons. The key requirement to the processes being developed was their universal application for processing of all the ore types using a single flowsheet. Due to the hard mining and geological conditions and because of complex material composition of Udokan ores it is of great difficulty to design a process which would provide for maximum economic benefits. That is why the process optimization has been ongoing until now.According to the Russian standards, the main input document for design of a metallurgical plant is referred to as a Process Design Report that covers the following key data sections: analysis of metallurgical testing results, validation of the process, design criteria, process flow diagrams, the mass and metallurgical balances, process description, equipment list and other information necessary for the subsequent design."

Jan 1, 2018

By T. Surkova

For the moment reserves of high-grade ores are practically depleted requiring ever-increased involvement of low assay raw materials, such as black-shale ores, in industrial operations. Black-shale ores are constituted of minerals containing such valuable components as vanadium, uranium, molybdenum, manganese, and rare-earth elements (REE). We studied technogenic solutions of black-shale ores processing, after uranium, molybdenum, and vanadium were recovered. Mentioned solutions contain rare-earth elements in substantial quantities (S REE 70-100 mg/dm3) that is very important factor taking into consideration the world demand ever-increasing last years. Higher concentrations of iron and aluminum inhibiting REE sorption and extraction recovery are found in solutions. We propose a method of hydrolytic deposition to cleaning solutions from impurity elements (Fe, Al). Study of hydrolytic deposition kinetics allowed identifying optimal conditions to run this process. Rare-earth elements may be recovered from purified solutions through sorption process followed by their further deposition from eluates in form of concentrates. Keywords: black-shale ores, rare-earth elements, a method of hydrolytic deposition, impurity elements, sorption

Sep 1, 2012

The flotation of nickel sulphide minerals is normally difficult in the presence of serpentine minerals due to the coating of serpentine particles on the nickel mineral surface. To improve the flotation, dispersants such as polyphosphate and carboxy methyl cellulose are normally used to remove the slime coating. However, in the flotation using high ionic strength process water, these dispersants are invalid due to their ionic nature. In this study, a new type of non-ionic dispersants, Pluronic triblock copolymers were examined with an objective of improving the flotation of ultrafine pentlandite (a nickel sulphide mineral) in the presence of lizardite (a serpentine mineral) in saline water. Three Pluronic triblock copolymers varying in solubility and hydrophile-lipophile balance (HLB) values were studied by flotation tests, settling tests and froth measurement. It was found that two of the copolymers improved pentlandite flotation against lizardite, and one copolymer deteriorated the flotation. The effect of Pluronic triblock copolymers on the flotation was actually linked to their dispersibility and foamability, which were governed by their physical properties. The two copolymers with a higher solubility or HLB value produced more stable mineral suspensions and more stable froth in the flotation resulting in better nickel grade and recovery in both rougher and cleaner flotation. Keywords: ultrafine particle, flotation, slime coating, dispersion, saline water, triblock copolymers

Sep 1, 2012

By Jonas Addai-Mensah

In this paper, the results emerging from the several basic and applied studies performed to provide fundamental understanding of the interplay between clay pulp chemistry, orthokinetic flocculation performance, particle interactions, applied shear and dewaterability of fine clay mineral dispersions are presented, reconciled, and discussed. Modification of pulp chemistry and behaviour was achieved by using kaolinite and Na-exchanged (swelling) smectite clay minerals, divalent metal ions (Ca(II), Mn(II)) as coagulants and high molecular weight, anionic polyacrylamide copolymers: carboxylate substituted (PAM A) and 2-amido 2-methyl propane sulphonate (PAM S) (PAM S), non-ionic polyacrylamide homopolymer (PAM N) and non-conventional, non-ionic polyethylene oxide (PEO) as flocculants. Clear links between pulp interfacial chemistry, particle interactions and dewatering behaviour, resulting from the influence of hydrolyzable metal ion, pH, temperature, polymer structure type and shear, are established. Optimum conditions for improved, orthokinetic flocculation performance of negatively charged clay particles, reflecting faster settling flocs (>10 m/h) comprised: (i) coagulation, (ii) moderate agitation rate, (iii) shorter agitation time and (iv) anionic rather than non-ionic PAM. The optimum flocculation conditions did not, however, have a significant impact on the final sediment solid content of 20 ? 25 wt%. Further application of shear to pre-sedimented pulps improved consolidation by 5 - 15 wt % solid. Application of the findings and new knowledge gained to real plant tails? case studies for marked improvement in dewaterability through thickening is demonstrated.

Sep 1, 2012

By B. Friedrich, A. Weyhe, H. Heegn

"Nickel-metal hydride batteries (Ni-MH) are storers of electrochemical energy, which have a higher specific storage capacity than lead or nickel-cadmium batteries. The demand for Nickel-metal hydride batteries is increasing rapidly since their market launch in the early 1990’s. Today there is no suitable and sustainable recycling process to recover nickel, cobalt and rare-earth metals. The discarded batteries are used today in the steel industry as alloy material because they contain nickel. Cobalt and rare-earth metals (RE) are lost; they are non-recycleable.In a German governmental funded research project, IME Aachen, ACCUREC Mühlheim and UVR-FIA Freiberg are cooperating in processing as well as in creating a feasibility study. The target of this project is the development of a new recycling process for metal recovery from Ni-MH-batteries. The proposed process described in this paper consists of a combination of mechanical, pyrometallurgical and hydrometallurgical processing steps. This process is capable of treating all types of Ni-MH-batteries. After comminution steel and organics are separated. The separated Ni-MH is smelted in an electric arc furnace. The products are a nickel-cobalt alloy and a slag phase enriched with rare-earth oxides for further treatment to ‘mischmetal’. Both the Nickel-Cobalt alloy and the ‘mischmetal’ will be directly used in battery production."

Jan 1, 2003

By Rogerio C. Guimarães, Antonio E. C. Peres

The production of phosphate concentrates (phosphate rock) from slimes represents a challenge to the phosphate industry worldwide. In Brazil, this challenge is particularly relevant due to the consistently low P2O5 grades and the igneous origin. The Brazilian phosphate deposits are made up mainly of apatite from alkaline chimneys, representing 80% of the Brazilian reserves; phosphorite deposits contribute 18% and the other sources (guano, phosphorous bauxite, and apatite from veins) reach 2%. The Brazilian industry beneficiates phosphate ores that are mineralogically more complex than those treated elsewhere. The low apatite grade, inherent to the igneous Brazilian ores, added to the mineralogical complexity due to the weathering of the rocks, has represented a permanent challenge to the Brazilian process engineers. The total measured, indicated and inferred reserves reach 3.2 million tonnes of ore with average grade 11% P2O5. The development of local technology for phosphate beneficiation started in the 1960’s. The first industrial experiences of producing phosphate rock from slimes (-44µm or -325#) fraction started at Arafertil, currently Bunge Fertilizantes SA, in Araxá, in the 1980’s. This production corresponds, nowadays, to 35% of the total production of concentrates in the company (830,000t/year) in a circuit consisting of desliming in 40mm microcyclones and concentration in flotation columns, corn starch and fatty acids being utilised as reagents. The performance of slimes flotation and the process control, at Bunge´s concentrator, were improved after the introduction of column flotation technology, in the first half of the nineties. The column flotation technology for slimes recovery was expanded to other Brazilian concentrators still in the nineties: Ultrafértil (Catalão – GO), Bunge (Cajati – SP), Fosfértil (Tapira – MG) and Copebrás (Catalão – GO). At present the Brazilian production of phosphate rock is approximately 4.5Mt/year, with a strong trend for a market increase. Genuinely Brazilian technology is utilised for the processing of slimes, the concentrates representing 11 to 13% of the overall production. The production of apatite concentrates from slimes was relevant to increase phosphate recovery and reduce costs, contributing to the growth of the fertilisers industry.

Jan 1, 2003

By O. V. Suvorova, V. G. Minenko, D. V. Makarov, A. L. Samusev, E. A. Selivanova

"Saponite is a valuable marketable product widely used foundry, metallurgy and construction, in the chemical, food and consumer goods industries, in medicine, and in agriculture.The feasibility of producing of high-quality construction materials with enhanced physical-chemical and decorative characteristics from saponite-containing products has been given a scientific basis and experimentally validated. The compressive strength of the samples in the sintering temperature range of 800-1000 ?? varied between 35 and 80.9 MPa; the bending strength 8 and 26.7 MPa, which is superior to the high-grade ceramic bricks of the M-300 brand. It has been established that the saponite-containing product obtained using the electrochemical separation of process water has a high sorption capacitance relatively the heavy-metal ions such as nickel and copper (40.7 and 99.8 mg/g, respectively). As a result of sintering at 750 ?? the sorption capacity of the sorbent for the nickel and copper ions increased to 194.2 and 212.8. Using the XRD and SEM with energy-dispersive spectroscopy studies, we diagnosed the metal-containing phases and validated the metal sorption mechanism.This study opens up the possibility of practical realization of the saponite-containing product as high-quality building materials and heavy-metal sorbents while addressing the issue of process water treatment. INTRODUCTION The Lomonosov deposit of the Archangelsk diamondiferous province accommodates 10 kimberlite pipes. The anticipated volume of diamond-bearing ore and dump rock to be removed before reaching the open-pit mining limit is 300 mln t (Karpenko, 2009; Bezborodov, etal. 2003). Rock in the deposit is almost completely displaced by clay minerals, predominantly saponite, amounting to 90% in the vent facies (Karpenko, 2009)."

Jan 1, 2018

By Elves Matiolo

This paper describes, in detail, results obtained from a research study of a complex iron ore aiming to produce a pellet feed concentrate with at least 65% of Fe and less than 3.5% of SiO2 in the final concentrate. The work includes an ore desliming followed by column flotation at laboratory scale. The ore sample was from Carajás province - Brazil and represents a complex low grade compact itabirite ore, analyzing 35.9% Fe, 45.1% SiO2 and 0.57% of Al2O3. Yet, the feed was treated previously by magnetic separation and grounded to 97% < 20 µm; this sample was named MAG 2. The chemical and mineralogical characterization of the MAG 2 sample showed that Fe and SiO2 grades were 50.7% and 24.3% respectively and was composed mainly by hematite, goethite and quartz. The particle size distribution, using a laser diffraction technique, showed that 90% of the particles were < 18 µm; 50% less than 8 µm and 10% minor than 1 µm. When the cationic reverse flotation without desliming was tested the selectivity of the process was very low and did not meet the concentrate metallurgical goals of the pellet feed product. However, when desliming was applied prior to flotation, a concentrate product with chemical characteristics of the pellet feed was obtained. The best results after desliming and column flotation achieved global iron metallurgical recovery of 72% with Fe grade in the concentrate of 66.5% and 2.1% SiO2 using starch as depressant for the iron oxides minerals at 1200 g/t ? 1500 g/t and an amine as the quartz collector at 100 g/t concentration (pH constant, at 10.5). It is believed that the desliming stage was key in the separation of the iron bearing particles and has a high potential for the flotation process of this type of ores.

Sep 1, 2012

By I. A. Agapov, I. S. Anisimov, N. V. Rylov, A. M. Sagitova

"The smelter slags represented silicate crystalline rock with medium to coarse-grained structure with spinifex skeletal network of olivine in hedenbergite matrix. Accessory magnetite, pyrrhotite and copper sulfides chalcopyrite, bornite, covellite, chalcocite and digenite occurred in dissemination in silicate matrix. The sample was studied by optical and electron microscopy with support of quantitative XRD. Modal mineralogical composition included olivine, pyroxene, magnetite, chalcopyrite, quartz, pyrrhotite. Copper deportment showed copper distributed in chalcopyrite (40 %), cuprite (22 %), covellite (21 %), bornite, chalcocite, digenite (5 %), Cu-bearing pyrrhotite (4 %) and spinel (2%). Liberation of copper minerals in the material ground to P80=71 µm was good with over 90 % sulfides in free grains and floatable binaries. The results showed theoretical possibility of 65 % copper recovery by flotation. Conclusion based on mineralogical data was precisely confirmed with flotation tests studies that proved to recover around 60 % of copper to commercial grade concentrate. INTRODUCTION Annual world copper matte smelter slags production is estimated to be millions of tones and contain thousands tones of unrecovered Cu, Zn and significant amounts of Ag and Au. Mineralogical study of one large processing sample of material of historical piles of Cu matte smelter slag was carried out to find possibility to recover copper and define theoretical recovery by flotation. The study of the slag material was aimed to determine possibility of upgrading the material on existing copper flotation plant to develop additional mineral resources. The objectives for mineralogical investigation were to target for best liberation fineness, determine theoretical recovery and possible concentrate quality for sulfide flotation tests. MATERIALS AND METHODS Large representative processing sample was collected by mixing of 120 t of slag material representatively excavated from historical piles of Cu matte smelter slag. The sample was used to define the processing technology to recover copper and gold from the material."

Jan 1, 2018

In this paper High Pressure Grinding Rolls(HPGR) was utilized to pretreat CVRD southern specular hematite for enhancing the pelletization of the refractory hematite. The process parameters of HPGR, balling and firing were optimized, and the mechanism of HPGR was demonstrated by determining the surface activity by means of Blaine specific surface area tester, laser size analysis, scanning electron microscopy (SEM),X-ray diffraction (XRD), micro calorimeter and pelletability index. It is shown that the pelletization of the refractory hematite was greatly improved. The drop strength of green balls increases from 3.4 times to 13.6 times from 0.5m height while the bentonite dosage decreases from 2.2% to 1.3%.The compressive strength of roasted pellets also reaches 2500N/pellet. The mechanism of the pretreatment of CVRD southern specular hematite concentrates by HPGR is revealed that the surface activity is improved by an increases in specific surface area and the amount of micron size fractions, and higher lattice deformation and defects due to the fractures occurring inside particles during static pressure comminution, resulting in more wetting enthalpy, higher pelletability index and good property of roasting.

Jan 1, 2014

By M. Morales, J. Yianatos

"In this work, an alternative approach to evaluate the flotation performance along a flotation rougher row is presented. The collection zone as well as the froth zone performances were separately evaluated. For this purpose, sampling for metallurgical balances along with sampling of top-of-froth (TOF) grades in each cell of a flotation row were employed. The modelling of the rougher circuit consisted of using TOF grades for evaluating the collection zone recovery, because they are a good representation of the bubble loading, which identifies the true flotation process, as shown in previous studies for shallow froths. In addition, the feed characterization, size-by-liberation, allowed the identification of the mineral distribution and its evolution along the circuit. The latter result was obtained by fitting the recovery profiles as well as the TOF grades down the flotation bank. The flotation rates and the maximum recoveries in terms of size-by-liberation (size classes: -45 µm, +45-150 µm, +150 µm, and liberation classes: -20%, +20%-80%, +80%) were then estimated. The results were in good agreement with those reported in literature by other authors and showed the new approach allows flotation kinetics to be characterized in industrial circuits.INTRODUCTIONMineral recovery in industrial flotation circuits is a function of the mineral characteristics, such as particle size distribution and liberation (Trahar, 1981, Jameson, 2012), and operating conditions such as air flowrate, pulp flowrate, solids percent and reagent conditioning (Jameson 1977; Klimpel, 1980; Mehrotra and Kapur, 1974). The cell type and size (self-aerated or forced air) and the circuit arrangement (single cells or banks of cells in series) are also relevant factors. Sampling of circuits (e.g. rougher, cleaner or scavenger) are commonly carried out using standard automatic samplers for metallurgical balance assessment. However, the flotation plants are generally not provided with proper accesses for local streams, which hinders the recovery estimations and the flotation rate characterization."

Jan 1, 2018