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By N. S. Voiloshnikova

Large-scale continuous ?Resin-In-Pulp? process tests were conducted at Irgiredmet. The object for testing was the sample of oxidized gold ore from one of Siberian deposit. Weak-base ion ex-change resin PuroGold was used as adsorbent. The duration of ?Resin-In-Pulp? tests was sufficient for a completing of three cycles ?Adsorption/Elution?. Gold in feed was 0.95 mg/L. Gold in solid phase of adsorption tails? 0.065 g/t. Gold in liquid phase of adsorption tails? 0.026 mg/L. Total gold in adsorption tails ?0.11 g/t. Gold recovery ?94.3 %. The use of regenerated resin had practically no effect on gold losses with adsorption tails. Alkaline cyanide solution (NaCN-20g/L, NaOH- 5g/L) was used as eluent for gold elution from loaded resin. Elution temperature ?60 °C. Number of eluent bed volumes passed ?10. Loaded resin analysis was following (g/ton): Au? 1700~1250; Ag? 400~460; Cu? 250~450; Zn? 5100~9600; Fe? 860~1200. Elution efficiency: Au? 95.3%~97.8%; Ag? 84.0%~88.0%; Cu? 84.0%~88.0%; Zn? 97.0%~99.0%. Although high zinc resin loading was shown zinc was eluted efficiently. The adsorption properties of fresh PuroGold resin, PuroGold resin after 3 cycle ?Adsorp-tion-Elution?cycles in comparison with AM-2B resin were tested. It was shown from adsorption isotherms that selectivity of PuroGold resin slightly less in comparison with AM-2B resin mainly due to its higher zinc adsorption properties. It was founded on base of test results that adsorption properties of PuroGold resin was practically constant during three ?Adsorption/Elution? cycles. Gold may be efficiently recovered by resin tested. There were no difficulties during gold elution from loaded resin and its regeneration. PuroGold resin was recommended for industrial use in RIP process. Process design criteria were developed and plant design is on progress at the moment.

Jan 1, 2014

By Sepideh Javanshir

The process of liquid?liquid extraction of gold from chloride solution is complicated by the presence of many variables acting simultaneously in an unknown non-linear fashion for the determination of the final extraction efficiency. In practice, it is quite difficult to develop a model for predicting various properties of such process. Therefore, an alternative approach based on Artificial Neural Network (ANN) is considered to assist in the simulation process. Artificial neural networks (ANN) are powerful tools that can be used to model and investigate various highly complex and non-linear phenomena. This paper presents application of Multi-Layer Perceptions (MLP) to construct relationship that will be employed to develop a quantitative method for the estimation of the extraction efficiency as a function of hydrodynamical parameters such as stirrer speed, [AuCl4]- and DBC concentration, organic and aqueous flow rate. The model is shown to be in excellent agreement with the experimental data (R2 value for training and testing data was 0.9992 and 0.9915 respectively). Therefore, it can be used to optimize the parameters of liquid?liquid gold extraction with dibutyl carbitol (DBC).

Sep 1, 2012

By X. Y. Liu

A culture-independent approach based on 16S rRNA gene clone library was used to analyze the bacterial community change both associated to the solids and in the liquid phase during pyrite bioleaching process. Phylogenetic analyses of 16S rRNA fragments revealed that the retrieved se-quences mainly related to genus Leptospirillum, genus Sulfobacillus and genus Acidithiobacillus. During the bioleaching process, genus Leptospirillum trends to grow associated to the solids while major of genus Sulfobacillus were in the liquid fase, only accounting little portion in the solids. Genus Acidithiobacillus can grow both on the solids and in the liquid phase, but accounting high portion on the solids.

Jan 1, 2014

By G. Bonifazi

Mining activities belong to human history, they are lost in the mists of time. They usually impact on large portions of the territory, both directly (exploitation areas and logistic activities directly related to exploitation) and indirectly (exploited material handling, processing and storage areas). As a result, at the end of mine life cycle, dismissed areas usually cannot be directly re-utilized without efficient and well addressed rehabilitation actions. Main goal of the proposed approach was to analyze the results obtained when a set of procedures, based on the collection and the analysis of remote sensed data, is developed to evaluate the effect of rehabilitation of land contaminated by extractive industry activities and to perform a monitoring and registration of the environmental impact of such operations by the application and the integration of modern information technologies, as Earth Observation (EO) and Geographic Information Systems (GIS). The study was developed in the framework of the EU-Asia program of the European union (EXTRACT-IT Project-Contract No: CN/ASIA IT&C/006 (89870): Application of Information Technologies for the sustainable management of Extractive industry activities) and it was addressed to three different dismissed mine areas in India, Thailand and China, respectively. The results, in terms of methodologies selected, strategies applied and results obtained, are described with particular reference to Fuxin coal mine area in China.

Jan 1, 2014

By E. Barsky

Physical principles of two-phase flows with a polyfractional solid phase have not received a sufficient theoretical interpretation as yet. Two-phase flows in the separation mode with a counter-flow of particles are even more complicated. Only statistical methods give an insight into general regularities of such processes. These processes can be interpreted best by analogy with the statistical model of an ideal gas developed by L. Boltzmann, although here a number of difficulties arise. The notion of a statistical system for such flows is substantiated. A mathematical estimation of a statistical system is presented. New notions are introduced, namely, potential extraction of a system and lifting factor. A relationship having the physical meaning of entropy is derived for a two-phase flow in the separation modes. The connection of this new entropy with flow parameters, such as the number of particles, separation factor and chaotizing factor, is established. Properties of this entropy are analyzed, as well as the analogy and difference between this entropy and Boltzmann?s entropy. The notion is formulated and the definition of the chaotizing factor of a process is suggested. In the framework of a statistical approach to two-phase flows in the separation mode, the notion of flow mobility has been formulated. Principal regularities of mass transfer in zone/apparatus sys-tem are analyzed. Principal ideas of a cellular model of the process are formulated, and main relationships for its description are derived. Proceeding from the cellular model, a dependence describing the degree of fractional separation of a narrow size grade is found. The analysis of this dependence makes it possible to reveal the crucial role of the Froude criterion for gravitational separation processes. It is found empirically that this parameter is a basis for the affinization of separation curves (Barsky E, Barsky M, 2006; Barsky, 1980).

Jan 1, 2014

By A. Gül

This investigation was carried out with low grade Murgul-Cakmakkaya copper ore once used to be dumped away as waste material. Sulphide minerals in the ore sample observed are chalcopyrite, pyrite, sphalerite and to some extent molibdenite; quartz, calcite and dolomite are the gangue minerals. The ore sample assays 0.28% Cu, 2.94% Fe and 3.36% S. Mineralogical study of the ore sample showed that adequate liberation of chalcopyrite for flota-tion was achieved below 100 µm. In flotation tests Aerophine 3418-A was the collector employed, NaOH or Ca(OH)2were the pH modifiers. Deactivators used were sodium meta bi-sulphide, starch, dextrin and lime. MIBC was the frother used throughout the tests. Test results showed that starch alone was the most suitable depressant to give the optimum metal content and recovery val-ues. Activated charcoal was used to adsorb excess collector species in the flotation pulp during cleaning stages After two stages cleaning of the rougher concentrate using starch as the depressant a copper concentrate assaying 21.2% Cu was obtained with 79.5% recovery while the tailings contained 0.01% Cu and metal losses were about 3%

Jan 1, 2014

By L. C. Zhou

The floatability of andalusite and associated minerals are studied and their action mechanisms of andalusite and associated minerals with collector alkyl benzene sulphonate are also studied. Through the mensuration of electrical potential and the infrared spectroscopy, as well as desorption tests, it is confirmed that the interaction of andalusite with sodium dodecyl benzene sulphonate (SDBS), is in addition to physical adsorption, but also is chemical adsorption. The study results of the pure minerals are used for the flotation of actual andalusite mineral. By flotation from contain-ing 45.68% andalusite ore, the fine andalusite concentrate is gained which Andalusite grade is 85.88%, containing Al2O355.29% and Fe2O3 less than 1.5%.

Jan 1, 2014

By R. M. Zhao

The process conditions and mineral characters of cleaning separation stage in magnetite concentration plant are studied in the paper, and the affecting factors and the methods to increase the concentrate grade are analysed and given. The BKJ cleaning special drum magnetic separator is developed specially for the cleaning stage according to process conditions and mineral character. The separation mechanism, structure characters, separation process and excellent adaptability of BKJ special magnetic separator are described. The results in Zhangjiawa Concentration Plant show that the BKJ special drum magnetite separators play an important role in increasing the concentrate grade and improving the economic benefit.

Jan 1, 2014

By P. Han

The preparation technological conditions and regeneration method of two novel granulated adsorbing materials of rectorite/fly ash composite (Material 1) and rectorite/water quenched - slag composite (Material 2) and the use of them to remove heavy metals from copper smelting plant wastewater have been studied. The experimental results showed that under the preparation conditions with the ratio of rectorite to fly ash or water - quenched slag of 1:1, the amount of the additive (Industrial Starch, IS) of 15% (Material 1) or 10% (Material 2), the addition of 50% water, and the calcination temperature of 500? (Material 1) or 400? (Material 2), the efficiency of heavy metal removal with the granulated materials was the best, whereas the ratio of disintegration loss was the lowest. Under the treatment conditions of natural pH, and with the addition of the granulated materials of 0.07g/cm3 (Material 1) or 0.05g/cm3 (Material 2), a reaction time of 60 minutes (Material 1) or 40 minutes (Material 2), and the adsorption temperature of 25?, the efficiency for the granulated materials to remove Cu2+Pb2+Zn2+Cd2+ and Ni2+ from the copper smelting plant wastewater was 98.9, 97.5, 96.7, 90.2, and 79.1, (Material 1) or 98.2, 96.3, 78.6, 86.2, and 64.2, (Material 2), respectively, and the quality indexes of the wastewater after treatment conformed with the first level of integrated wastewater discharge standard (GB8978-1996). When the adsorption of heavy metal ions on the surface attained saturation the granulated materials could be regenerated by washing with 1 mol/L sodium chloride (NaCl) solution and still with quite good heavy metal removal efficiency. The granulated adsorbing materials had the advantages of high efficiency of wastewater treatment, easy method of solid-liquid separation and regeneration, and a broad prospect of applications.

Jan 1, 2014

Rotor speed is one of the key hydrodynamic parameters in froth-flotation and it plays an important role in bubble-particle attachment. Laboratory scale studies for optimizing the rotor speed to achieve maximum flotation rate constant (K) of quartz, ground by ball mill, are. Purity of quartz was 99.4 percent and d80 of ball mill product was 230 µm. Each size fraction was separately subjected to flotation at three different rotor speeds, namely, 1200, 1000 and 800 rpm, and the flotation rate constant was calculated. The results showed that the flotation rate constant was high at the rotor speed of 1200 rpm. The flotation rate constants achieved at 1200 rpm were 8.676, 8.232, 7.818, 7.248, 7.068 and 6.984 min-1forthesize fractions of +300, -300+250, -250+212, -180+150, -150+125 and -125+106 µm, respectively. Keywords: froth flotation, rotor speed, flotation rate constant, ball mill, quartz

Sep 1, 2012

By F. Göktepe

Flotation gases and conditioning of the pulp with them are one of the important parameters of flotation and should be taken into account especially in the flotation of sulphide ores. In this study, flotation of pure chalcopyrite and pyrite samples were investigated with air, oxygen and nitrogen as flotation gas and the effect of conditioning with these three gases also were performed. Flotation gas was introduced for 5min, 10min, 15min and 20 min. For chalcopyrite flotation there was no drastic change in recovery when air, oxygen and nitrogen were used as flotation gas but conditioning the pulp with oxygen for 10 minutes increased the recovery about 8% where pulp potential has been approximately 25 mV with chalcopyrite and 150 mV with platinum electrodes. Conditioning with all three gases decreased the pyrite recovery by about 20% with 20 minutes conditioning. Pulp potential decreased in the presence of nitrogen while conditioning with air and oxygen increased the pulp potential for both electrodes. Generally potential increased for both minerals with oxygenation and aeration time but it was stable or slightly decreased with nitrogenation. Comparison of the gases showed that the different flotation gases do not effect flotation recovery but conditioning the pulp with these gases at pre-flotation effects chalcopyrite and pyrite flotation recovery, most dramatically pyrite.

Jan 1, 2014

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

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

Jan 1, 2018

By J. Langwaldt

Ammonium-nitrate is a main component in blasting agents and dissolved ammonium residues may be discharged with mine water. The European Union aims to reach a good state of the water quality and recommends ammonium content below 0.5 mg/L for drinking water. Natural zeolites adsorb ammonium from water. In this work, the removal of low-concentration ammonium by commercial natural zeolites was studied in continuous tests. Natural zeolites made up between 83% and 95% of the mineral composition. The major zeolite minerals were chabazite and clinoptiolites and minor amounts of erionite and mordenite were as well present. The five natural zeolite samples, 500~710 µm, were conditioned to obtain zeolites in the Na-form. Ammonium adsorption onto natural zeolites depends mainly on the zeolite mineral type. The chabazite containing zeolite was superior over the four clinoptiolite samples for the removal of low concentrations of ammonium from water (pH of 7.5, flow 5 mL/min, room temperature). The adsorption capacity of chabazite was 48.3 mg NH4+/g zeolites, i.e. 73% of the theoretical exchange capacity 69 mg NH4+/g, during duration over 107 days and almost 6700 bed volumes exchanged. The four tested clinoptiolites had an ad-sorption capacity of 15.7mg to 25.0 mg NH4+/g zeolites. The natural zeolites were rapidly regenerated by an alkaline sodium chloride solution fed to the columns.

Jan 1, 2014

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 Ricardo Montero

At this time, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc. After the use-phase, the electronic devices become electronic waste (e-waste); consequently it is important to consider e-waste as a secondary supply for recovery of these metals. One of the most important components is the printed circuit boards (PCBs) because the amount of their precious metals is ten times higher than rich precious metals bearing ore. This paper presents the recovery of Au, Ag, Cu and Nb from PCBs of discarded computers using leaching column technique. The amount of these metals in used PCBs was: 613 g/ton of Au, 1515 g/ton of Ag, 36 g/ton of Nb and 23.4 % of Cu. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm. Then, it was leached with sodium cyanide solution in a glass column using the following conditions: sodium cyanide concentration 4 g/L, flux 20 L/kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained: 46.6% of Au, 51.3% of Ag, 47.2% of Nb and 62.3 % of Cu. The products obtained are: a) loaded carbon that contains the desired metals and b) processed PCBs with precious metal contents. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of US$ 155 639, considering the recovered metals from loaded carbon. The internal rate of return for 10 years period (IRR) and net present value (NPV) estimated are 27% and US$ 105 926 respectively. Keywords: printed circuit boards, recovery, precious metals, niobium, leaching column

Sep 1, 2012

By Z. G. Song

As a kind of complex physicochemical process, grinding would affect the subsequent mineral processing such as flotation considerably. In this study, the effect of wet grinding on malachite and calcite flotation using sodium oleate as collector was studied. And the mechanism of the effect of grinding was investigated. Laboratory scale grinding and flotation testing of malachite and calcite samples were performed. Different grinding media were used, including steel balls and zirconia balls. It was the aim of this work to study the effect of grinding on the pulp chemistry paying particular attention to flotation recovery. The effect of grinding media and different addition location of sodium oleate on malachite and calcite flotation was studied. The methodology used in this project involved grinding the ore with and without the addition of sodium oleate in mill, measuring the pH and metal ions produced by minerals after grinding, adding various quantities of sodium oleate and determining the copper recovery. The presence of species of products on the minerals after grinding was probed using X-ray photoelectron spectroscopy (XPS), and the metal ions produced by minerals after grinding were measured by atomic absorption spectrometry (AAS). It is showed that the mil-ling environments evaluated significantly affected the flotation of malachite and calcite. This study also discusses the effecting mechanism of grinding environment on floatability of malachite and calcite.

Jan 1, 2014

By M. D. Vilarinho, W. Xuan, F. Vasconcelos Guimarães

"This article summarises the efforts to reduce the energy consumption in grinding in a magnetite ore beneficiation plant. ArcelorMittal Kryvyi Rih ore beneficiation plant produces magnetite concentrate at 65% Fe and 8% SiO2, of which the D80 is approximately 44µm after three stages of grinding with ball mills and magnetic separation. Characterisation and laboratory scale bench tests performed on samples from the beneficiation plant indicate that the industrial flowsheet could be simplified. After the first stage of grinding and magnetic separation, a significant size fraction of the intermediate concentrate is already well liberated. Therefore, it can be directly concentrated in a second stage magnetic separation without further grinding. If a screen of 150µm size can be implemented after the first stage of grinding-magnetic separation, only the oversize of screening, representing 35% of the material, requires secondary and tertiary grinding and magnetic separation. The combined concentrate from the two fractions already meets the industrial specifications. This new route can provide the same final product, with fewer mills; it saves around 30% in energy consumption only in the grinding step without changing the main structures of the processing plant.INTRODUCTION Comminution, including crushing and grinding, is responsible for at least 40% of total energy usage in mining and mineral processing. This paper shows an example to reduce grinding cost, by changing the flow sheet design strategy in ArcelorMittal Kryvyi Rih (AMKR).AMKR is one of the most important mining and steel complexes in Krivoy Rog basin in Ukraine, which has been studied over 100 years because of mining of iron ores. The iron ores are associated to Banded Iron Formation of the Saksagan suite, with an average iron grade of around 36 percent Fe. The total thickness of the Krivoy Rog Supergroup reaches 5-6 km, whereas that of the iron-ore Saksagan Group comprises up to 1400 m. High-grade iron ore extends to more than 2,000 m below present surface"

Jan 1, 2018

By X. W. Zhang

Mica plate is broadly used in electric industry, production of man-made mica paper plate is in-creasing. The problem coming with is that large quantities of leftover materials unable to be re-cycled are produced during cutting and molding of mica plate productions. The leftover materials are always abandoned as crabs, which not only pollute the environment but also waste our resources. The study intends to find a new measure to decompose and to reuse the mica plate leftover materials so as to create a new production process of mica plate, which is clean and does not produce crabs.

Jan 1, 2014

By G. Jenny

The particle size distribution of ground minerals is of decisive importance for downstream processes like floatation, separation, drying or others. In order to optimize the process efficiency on one hand and the final product quality on the other hand an early control of the grinding or classification stage is essential. The ultrasound based particle size analyser OPUS is capable of performing on-line particle size distribution (PSD) and solid content measurement of mineral slurries such as iron ore, copper ore, fluorspar, or quartz sand and alumina directly in heavy and rough process environment. The instrument provides a PSD of 31 size classes and can be applied for particles from nanometer range up to several millimetres. Arbitrary interpolations in between the 31 measured points are available. Typical residue values show an excellent agreement to off-line particle size analysis methods such as e.g. sieve analyses or laser diffraction. OPUS is designed as rugged in-line probe made from stainless steel. The applied technique is independent of product flow dynamics, contamination, optical properties, vibrations, pressures or changes in solid concentrations. The instrument provides all data on the system?s PC or on the process control system by a variety of interfaces.

Jan 1, 2014

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