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By Nóra Schreithofer, Zoltán Jávor, Kari Heiskanen

"One of the challenges the mineral processing industry is facing is caused by the fact that water resources in mining areas are becoming very limited and the cost of water is increasing. The water sources in arid regions often have high salt content. Environmental regulations are forcing plant operations towards completely closing the water cycles within plants. This means that impurities (salts, reagents, ions dissolved from minerals, etc.) accumulate within the circuit that will affect the flotation performance. Water purification can significantly increase the operating costs therefore it should be carefully considered weather the impurities need to be completely removed or is there a tolerable level of impurities that can still be left in the process water without significant deterioration of the flotation performance? Several additional questions arise: what are the tools that help identify what is a tolerable level of impurities? How do the different impurities interact and what is their effect on the process? The effect of frothers on the dynamic properties of air/liquid interface in different size-scales has been extensively studied by the authors in the past. Based on these studies a frother characterization framework was developed that systematically examines the dynamic surface properties of the air/liquid interface in relation to the bubble size. This work can be considered as tool that could be used for the above mentioned purpose. The present study investigates weather the same frother characterization framework can be applied for systems where both frother and different types of salts are present. Nasfroth 240 was used as a frother, in combination with structure-breaker KCl or structure-maker NaCl and CaCl2. Bubble size measurements in laboratory scale mechanical flotation cell and laboratory flotation column and dynamic surface property measurements (dynamic surface tension and dilatational elasticity) were performed. The results highlighted the addition of salt to the frother solutions significantly decrease the bubble size and increase the froth high. The coalescence behavior of bubbles showed correlation between the D32 and ionic strength of salts. The results highlighted that the studied structure maker and structure breaker salts effect the dynamic surface properties in different way."

Jan 1, 2014

By Henrique Kahn, Daniel Uliana, Juliana Antoniassi, Viviane Shimizu

"Mineral exploration and geometallurgy require a large number of samples for physical, chemical and mineralogical assays. The combination of all these data and their spatial distribution define the ore variability. This is important in exploration programs and crucial in feasibility studies as well as at the production operation level. Ore mineralogical composition and its associations, characterizing the geological formation and mineralization, are the main keys to define the ore domains and its variability, which can be quickly assessed by cluster analysis and by modern automated mineralogy tools. One hundred and ten copper ore samples from Sossego mine, in Brazil were compared and classified by X-ray diffraction cluster analysis based on the position and the intensity of the diffracted peaks. Initially four ore types were categorized based on content of major minerals: quartz, feldspar, amphibole, iron oxides, mica and chlorite. Results showed a strong correlation between the grouping and the samples location in Sequeirinho and Sossego orebodies, with a straight link to types/intensities of hydrothermal alteration prevailing in each body, which reflects the mineralogical composition and thus the X-ray patterns. Samples from four recognized ore types were submitted to detailed automated mineralogical studies by electron beam image analysis and differ strongly from each other regarding their chemical and mineralogical compositions and relevant parameters for mineral processing. Chalcopyrite is essentially the only valuable mineral, occurring both as submillimetric grains included in other minerals and as larger crystals. Except for pyrite, other sulfide minerals occur as traces. Chalcopyrite liberation curves indicate that samples from Sossego have higher liberation degree than those from Sequeirinho. The proposed method proved to be very efficient and accurate to classify a large number of samples within a short time frame, allowing the distinction of the ore types regarding their mineralogical composition as well as the mineral processing parameters."

Jan 1, 2014

By Stephen Gay, Dewetia Latti

"When improving a plant a mineral processing engineer would like to know the mineral composition distribution. In order to assess this distribution in particles, as compared to the corresponding distribution in particle sections, a procedure needs to be applied to the observed particle sections. Such a procedure is called a stereological correction. There exists many stereological correction procedures, but one group of such procedures is based on using those stereological equations that do not require making assumptions regarding particle shape or texture.In particular Davy derived an equation to estimate the covariance of mineral composition distributions for particles from both particle sections and linear intercepts. Furthermore, this covariance can also be used to measure the variance of the composition distribution of each mineral.This paper shall present results verifying this equation. The experimental method was based on obtaining particle information from serially-sectioned particles. Particle samples selected for serial sectioning displayed a range of natural textures including liberated, binary and composite particles. The exposed surface of the polished sections were analysed using QEM*SEM. This procedure was repeated until all of the grains have been polished away. The covariance of mineral distributions were calculated from the serial sections and compared with that calculated using Davy’s equation."

Jan 1, 2003

By Peter Ay, Harry Pempel, Satya Narra, Mike Müller, Jens Markowski

"Within the next few years major changes in mobility are expected. Increasing numbers of electric powered cars, electrobikes and E-Scooters define the transport sector. Recently lithium based traction batteries as storage medium have led into matrurity of series production combining high electrical efficiencies with low weights and compact dimensions. Due to the relatively young development with lithium batteries utilization, only few investigation were conducted regarding their recycling. Conventional battery recycling processes can not be applied due to differences in design and chemistry. So an automated disassembly and processing procedure for lithium traction batteries has been developed in the R/D-project ""Li-WERT"". Instead of complete smelting of the batteries without pretreatment, an automated disassembly and specific treatment of the material streams was realised, adjusted to the needs of the subsequent recovery technologies. A higher quality, with reduced expenses for the separation of fine-grained or fused material mixes, can be obtained for the individual components. The automated disassembly using an industrial robot significantly reduces dangers for the operating crew. The selective disassembly and beneficiation allows full recovery of the fractions. The batteries will be disassembled to cell level by the industrial robot. Anodes, cathodes, and separation layers are isolated and processed. The technology is designed, that no waste is generated for disposal. The pelletised cathode coating and the other separated metals (stainless steel, copper, aluminum) can be used in respective metallurgical plants. Circuit boards and plug contacts are also coveted secondary raw materials for reuse. The process is modular and offers high flexibility, e. g. for new battery types/ sizes by quick adjustment of the robot and tool change. Adaptation to other cathode materials (e. g. Li[FePO]) is possible. After finishing the R/D-project, a pilot plant for demontage was realised in 2013."

Jan 1, 2014

By Aldo Cipriano, Fernando Estrada

The mining industry is in search of control strategies that allow considering a global optimization of their processes, ensuring their stability. This has led to the application of recently developed control techniques on large-scale systems in the mining processes. One of the most important process of the mining industry is the mineral grinding, as the product particle size impacts, in a significant manner, the recovery rate of the valuable mineral in the separation stages. As a solution, a centralized hybrid model predictive control (HMPC) is presented; this control approach maintains the product particle size on a defined range and minimizes energy consumption, maintaining the grinding plant in a stable operation. As a comparison, a conventional model predictive control with an expert system to handle discrete events was developed, showing HMPC is a suitable solution that can used in the grinding process, with the benefit that it handles in the same controller both discrete and continuous dynamics and events.

Jan 1, 2014

By Rong Fan, Andrea Gerson

"The small recovery of Ag, often in the order of 50%, by traditional flotation and leaching process strategies is closely related to the complicated and heterogeneous nature of Ag-bearing minerals with Ag typically being associated with numerous minerals within any given ore-body. Moreover, grain sizes may be extremely fine with micron-scale common. In order to design cost-effective Ag-bearing mineral flotation and leach recovery strategies it is firstly necessary to characterise the speciation of Ag and its correlation with other elements, e.g., Cu, As and Sb, within the ore matrix and process streams. The traditional QEM-SCAN analytical approach can prove problematic for some mineralogies due to difficulties in recognising degrees of crystallinity, polymorphs, complex solid solution series, high value trace element mineralogy, very fine grained materials; and the requirement for a comprehensive data base. Moreover, there is difficulty ‘seeing’ either surface films or surface contaminants which can both lead to poor flotation performance. There is therefore clearly a need to develop confirmatory and complementary approaches when these uncertainties arise. Synchrotron X-ray microprobe analysis provides a powerful tool for the mineralogical characterisation of finely segregated heterogeneous Ag-containing materials. These measurements enable comprehensive characterisation of the Ag-bearing components using synchrotron microprobe X-ray fluorescence mapping (µ-XFM), X-ray diffraction (µ-XRD) and X-ray absorption spectroscopy (µ-XAS). Further analytical strength is provided by principal component analysis of laboratory ToF-SIMS data which enables the statistical identification of correlated surface species enabling examination of surface chemical characteristics responsible for mis-reporting of Ag containing components within flotation streams. We describe the application of these techniques to a selected Ag-containing feed and tail and demonstrate how these compliment and extend traditional analytical methodologies."

Jan 1, 2014

By R. Prakash

Column flotation has now gained wide application in the recovery of various minerals. The performance of the flotation device depends on the mixing characteristics of the phases inside the devices. In this work, quality of mixing in a flotation column has been analyzed by using information entropy theory. Empirical models have been developed for flotation column with the parameters which affect the quality of mixing. The efficiency of the particle separation in the flotation column has been enunciated based on the quality of mixing. The present analysis on the quality of mixing in flotation column may give insight into a further understanding and modeling of flotation devices in industrial applications.

Sep 1, 2012

By O. N. Mohanty, S. Mohan Rao, N. D. Rao, T. Mukherjee, P. V. T. Rao

"Tata Steel has its captive chromite resources at Sukinda, Orissa. They contain two ore types, i.e. (i) Ferruginous and (ii) Siliceous. The generation of off-grade ores is an increasing trend and simultaneously customer quality requirements are becoming ever more stringent. The ferruginous type ore also contains a considerable quantity of in-situ fines (~20% particles below 0.5 mm) that compound the beneficiation problem.In this paper, new strategies are discussed for producing additional value.added products after evaluating the present beneficiation practice in terms of changing market scenario, processing capability of the plant and ore characteristic. They would entail use of MGS - an enhanced gravity separator, for recovering additional products from plant tailings; production of ferruginous coarse concentrates (-3+0.5 mm with ~46% Cr2O3) using jigs; production of marketable grade lumpy (-40+10 mm size) concentrates from low grade siliceous ore using jigs and >2.8 Cr/Fe ratio siliceous ore fines treated in the Chrome Ore Beneficiation plant gravity circuit units and low intensity magnetic separator. The studies indicate that it is possible to recover 79-80% of the chromite, against a theoretical maximum of 82% from both the ore types, in the form of several marketable grade concentrates that would also include refractory grade."

Jan 1, 2003

By T. Fujita

A high-grade fluorite ore is converted into hydrogen fluoride to produce many kinds of materials containing fluorine. Recently, it is becoming necessary to use low-grade fluorite ore due to the depletion of high grade ore. The low-grade fluorites usually have impurities such as SiO2, P, CaCO3 and arsenic. The most impurities such as SiO2, CaCO3 and P can be removed by using flotation method. However, the removal of arsenic is difficult, and the arsenic contamination decreases the hydrogen fluoride production percentage. The novel technologies for processing low-grade fluorite ore are urgently needed, in order to lower the arsenic concentration to less than 100 mg/kg. In this study, the removal of arsenic from low-grade fluorite ore has been investigated by means of an autogenous grinding using tower mill in sulfuric acid aqueous solution and 0.3 mm zirconia balls in water. The nano grinding in water can prevent the dissolution of 0.3 mm size zirconia balls as grinding media by sulfuric acid solution. Experimental results showed that the arsenic concentration was reduced from 260 mg/kg to 90 mg/kg and CaF2 recovery reached 90% by this process.

Sep 1, 2012

By Andrzej Luszczkiewicz, Alicja Bakalarz

The application of new collectors is considered to improve the beneficiation of Polish sedimentary complex copper ores from the Legnica-Glogow Copper Basin (SW Poland), the upgradeability of which becomes more difficult because of ores grade declining. One group of potential collectors is represented by nonpolar reagents. According to the available literature data, only selected sulfides float in the presence of the nonpolar liquids. The paper presents laboratory scale flotation results for the main sulfide minerals occurring in the Polish copper ores applying either thiol (potassium ethyl xanthate) or nonpolar (aqueous emulsion of n-dodecane) collectors. The investigated feed contained 1.91 % Cu in the form of sulfide minerals such as bornite, chalcopyrite, chalcocite and covellite. Other sulfide minerals including galena, pyrite and sphalerite were also present in the samples. Several flotation tests with various doses of each collector were conducted. Mineralogical analyses of flotation products were carried out and the results compared. A comparison of the results indicated that all sulfide minerals floated well with high recoveries ranging from 91 % to 99 % in the presence of the thiol collector. The use of the nonpolar collector provided results in flotation of sulfide minerals with different terminal recoveries from 61 % for chalcopyrite to 100 % for sphalerite. The most significant differences in flotation in the presence of both types of collector under various conditions of upgrading were observed for chalcocite, chalcopyrite and covellite. Similar flotation results were observed for sphalerite and galena for both collectors. The studies confirmed selective flotation of sulfides from the copper sulfide ores of the Legnica-Glogow Copper Basin in the presence of nonpolar collectors.

Jan 1, 2014

By Wolfgang Öfner

Many technical processes also yield dusty residues which usually contain appreciable amounts of valuable matter. Often they also accumulate substances detrimental to the process. Dumping them entirely in landfills wastes raw material and causes high disposal costs, but recycling them without prior treatment is often not feasible. Physical separation processes are preferable because of their rather low energy demand. In order to develop such treatment systematically, the residues must be characterized properly. The technique for such a characterization is taken from mineral processing: perfect fractionation according to continuous properties of the particles supplemented with chemical analysis are used for plotting the Henry-Reinhardt chart. This represents the benchmark for assessing actual separation processes and tests. Their results are compared in terms of ?selectivity? and plotted in the kappa chart. In this paper, Henry-Reinhardt chart and kappa chart are applied to several different types of residues from iron and steel production and show their potential for being upgraded before reutilization in the production process. This approach is suitable for virtually all dusty residues from other industrial processes as well. Keywords: residue, dust,iron and steel, process development, Henry-Reinhardt chart, kappa chart

Sep 1, 2012

By Anatoly Usov

The detailed researches of a broad circle of problems connected to development of the electric pulse method destruction materials (EPD) of a various nature and area of use are executed. The electrical and power characteristics of process, physical fundamentals of selectivity of a breakdown and destruction are investigated, the device of electric pulse (EP) disaggregation and ?omminution of materials are developed, the technological efficiency of disintegration of industrial minerals estimated. Due to its technological advantages, the EPD could have a great potential in minerals mining and processing technologies. Low specific power and weight-and-size characteristics of EP installations based on the existing out-of-date electric equipment are at present the main reasons hindering the effective application of the method in mining and processing technologies. The main studies carried out in Russia in the field of electro technical equipment development for EP technology are presented. The pulse capacitors service life affects greatly the economic efficiency of the process because the capacitors cost accounts for a considerable, and in some cases, the most part of the operational costs. Determined and analyzed in the study are the ways which could significantly improve the specific characteristics of high voltage pulse generators (VPG), such as to use of high-frequency voltage transformation to develop a charger; to use pulse transformers (PT) with iron magnetic circuits made of materials characterized by high magnetic permeability, in pulse generating circuits; as well as to use special ways which could produce voltage pulses with a short front. The experiments have proved the possibility to adapt these technological solutions for EP devices, and a further strategy of the EP technologies development and application has been suggested on this base. Keywords: electric pulse disaggregation, electric pulse installation, charger battery, high voltage pulse generator

Sep 1, 2012

By W. S. Eu

Reduction of weathered mineral ores can initiate phase transformation which can affect either their activation or deactivation, subsequently influencing the extent of extraction of desired metals in a leaching reagent. The reduction of ilmenite ores for one occurs as a series of parallel, solid state reactions which at present has no known mechanisms, although the evidence of their effects is abundant. Understanding these reactions may well be the key to uncovering the mechanism of ilmenite activation, hence enabling precise control of its reaction process to maximize yield of TiO2 extraction. However, documenting the solid state reactions in the reduction of ilmenite is challenging due to the ore complexity, the number of simultaneous reactions and the difficulty of capturing critical intermediate reactions and phase transformations during processing. The phase transformations of ilmenite minerals reduced at temperatures up to 850°C were investigated in this study. Mineral transformations were studied in-situ using synchrotron radiation based X-ray powder diffraction with temperature resolved tests. The effect of the extent of reduction and specific mineral transformations were verified by leaching reduced ore with sulphuric acid. The re-sults suggest that transformation of major mineral phases occurs within of specific window of operation and thermal treatment appears to influence the extent of activation and leachability of ilmenite minerals.

Jan 1, 2014

By Seungwoo Park, Gaurav Soni, Roe-Hoan Yoon, Hyunsun Do, Kaiwu Huang

In a flotation froth (and foam), air bubbles become larger due to coalescence, causing bubble size to increase, bubble surface area to decrease, and hence casing less hydrophobic particles to drop off to the pulp phase below. Thus, bubble coarsening provides an important mechanism by which product grades are increased. On the other hand, excessive bubble coarsening results in low recoveries. In the present work, a model describing the process of bubbles becoming coarser in a foam as they rise to the top by deriving a mathematical relation between the Plateau border area, which controls film drainage rate, and the lamella film thickness, which controls bubble-coalescence rate. The model has been derived by assuming that liquid drainage rate increases due to slip at the air/water interface, and that the critical rupture thickness is determined by the capillary waves created by thermal motion. The model developed in the present work can predict the bubble size ratio between the top and bottom of a foam as functions of aeration rate, foam height, and surface tension (frother dosage). The model predictions are in good agreement with the changes in bubble sizes measured using a high-speed camera.

Jan 1, 2014

By Rakesh Kumar, S. Mehrotra, T. Alex

"This paper, an overview of our recent findings on mechanical activation (MA) of minerals/materials, emphasizes the importance of sample genesis, mechanically induced/altered porosity and surface area, mineral interactions, glassy inorganic materials, surface alteration and zeta potential changes and, mechanically induced reactivity of solids. Materials investigated include Al-oxyhydroxides (gibbsite and boehmite), fly ash and granulated blast furnace slag. Planetary, attrition, vibratory and conventional ball mills are used for MA. Genesis of boehmite has been found to have a bearing on its behavior during MA. For example, BET specific surface area (SSA) of boehmite prepared by thermal dehydroxylation of gibbsite has decreased from 265 to 65 m2/g during 240 min of MA; in contrast, the SSA of hydrothermal boehmite has increased from ~2 to 36 m2/g. Mechanisms of surface area changes in the two boehmite samples differing in their genesis is explored. MA of gibbsite and its mixture with hematite/quartz using attrition milling has indicated that the presence of the second phase promotes amorphisation. Amorphous materials show signs of change in nature of bonding during milling as illustrated by MA of fly ash. Physicochemical changes during MA are not restricted to the bulk phase. The genesis of zeta potential changes in MA solids can be many; for example texture induced zeta potential changes as observed for gibbsite, while zeta potential changes during the milling of granulated blast furnace slag occur due to enhanced (possibly non-congruent) dissolution. Interesting manifestations of mechanically induced reactivity and its correlation with physicochemical changes are illustrated in terms of alkali leaching of boehmite and, hydration of MA slag. New findings reported here are associated with several open questions and are highlighted in the paper."

Jan 1, 2014

By Yong Liu, Peng Qian, Shu-Feng Ye, Shao-Jun Chu, Pei-Wei Han

"Chromite with a low mass ratio of Cr to Fe (Cr/Fe ratio) was treated by the carbochlorination method using solid chlorinating agent (MgCl2 and CaCl2) and carbon in the present paper. The results showed that iron could be selective removed mainly in the form of FeCl2. The removal of iron was indirectly, which consisted of the decomposition of solid chlorinating agent to release Cl2/HCl and the carbochlorination of FeO•Cr2O3 by Cl2/HCl and C. The Cr/Fe ratio increased as increasing temperature from 700 ? to 900 ? in air atmosphere, while the tendency was opposite in N2 atmosphere. The removal efficiency of iron by CaCl2 was better than that by MgCl2. At last, a new pelletizing process was proposed to treat fine chromite with a low Cr/Fe ratio based on carbochlorination method, which could produce the high quality roasted chromite pellets with higher Cr/Fe ratio and compressive strength. INTRODUCTION Chromite is mainly used for the production of ferrochromium. A high Cr/Fe ratio (>2) of chromite is usually required to meet the technical specification of ferrochromium.(Gasik, 2013) Attentions have been attracted to the economic and efficient methods for the recovery of chromium from lower-grade ores as the higher-grade ores become depleted. However, the Cr/Fe ratio is difficult to improve through the conventional beneficiation methods (such as gravity concentration, flotation) due to the spinel composition, although beneficiation methods could increase the metal content of chromite ores by removing gangues.(Nafziger, 1982) The main industrial mineral of chromite is (Fe,Mg)O•(Cr,Al,Fe)2O3, which belongs to spinel magnetite.(Liu, 2013) Iron should be selectively removed through the structural dissociation of spinel to increase Cr/Fe ratio.(Nafziger, 1982)"

Jan 1, 2018

By Heinrich Hutchison, Thomas von Moltke, Roelof F. Sandenbergh, Katarina P. Cerovic

In the leaching of gold in aqueous cyanide solutions the rate of gold leaching may be decreased by the passivation of the gold, that may however be prevented or reversed in the presence of lead species in solution. In the present study potentiostatic, potentiodyanamic and XPS (X-ray photoelectron spectroscopy) analysis were used to further clarify the action of lead ions on the anodic activity of gold in alkaline cyanide solutions. It was found that lead increased the gold dissolution rate as it deposited on the gold surface at potentials more positive than its reversible Nernst potential for bulk metal deposition, i.e. by underpotential deposition mechanism, but that it decreased gold activity if present as bulk plated lead on the gold.

Jan 1, 2003

By F. O. Milovich, V. A. Ignatkina, L. A. Samatova, E. D. Shepeta

"The aim of the research was to increase technological parameters of the flotation of finely disseminated scheelitecarbonate ore using selective reagent regime.In the studies the monomineral fractions of scheelite and calcite; samples of the scheelite-carbonate ore of the Primorsky deposit with the range of the carbonate module 3-65 were used. A carbonate module of ore is the ratio an initial assay of calcite to an initial assay of scheelite. Sodium oleate, iso-decyl alcohol, water glass, calcium chloride, soda or sodium hydroxide as flotation reagents were used. The flotation method in the Hallimond tube and in a mechanical cell, an adsorption method for study the kinetics of adsorption of oleate and isodecyl alcohol and its combinations on scheelite and calcite, IR spectroscopy including ATR to study the composition of surfacecompounds were applied. Selective reagent regime may include two ways - a combination of collectors or a modification of depressants of calcite and other gangue minerals. On one hand the combination of sodium oleate and higher fatty iso-alcohols of fractions C12-C16 in the rough scheelite flotation to reduce the flotation activity of calcite has been studied. On the other hand depression of calcite flotation by calcium chloride with water glass into rough flotation was used; modified the steaming cycle by Petrov's method applying change the concentration of water glass and other. Fatty iso-alcohols can adsorb on the surface of the calcite that reducing the adsorption of sodium oleate and floatability of calcite has been fallen. Their co-adsorbing with oleat on the scheelite surface were support the hydrophobization and flocculation of slime particles of scheelite. Flocculation of the particles of scheelite leads to increased up 3 times of the recovery of scheelite from the slime class, and calcite change up only 1.4-1.1 times it’s recovery.The growth of the carbonate module more than 11 is decreased the assay of WO3 in the scheelite concentrate of selection cycle."

Jan 1, 2018

By N. D. Dementieva

Based on lab and pilot-plant tests to recover gold, silver and lead of a Russian deposit, a collective and flotation concentration flow sheet with lead and sulfide concentrates was proposed. The type of the deposit is gold-sulfide-quartz-bearing. The recovery of gold, silver, and lead to a lead concentrate was 47.4%, 68.1% and 70.7%, respectively. The grade of gold and silver grade was 170 g/t and 372 g/t, respectively. The mass percent of lead, zinc and arsenic mass percent was 41.7%, 0.34% and 0.63%, respectively. The recovery of gold and silver recovery to a sulfide concentrate was 50.1% and 28.8% at the grade of gold 20.5 g/t and silver 66.2 g/t. Sulfide concentrate with arsenic mass percent ~3% was biooxidised followed by CIL and obtaining metal at the site as well as zinc concentrate from bioleaching solutions with zinc mass percent 45% at its 64% recovery. The total gold and silver recovery using a developed technology with the account of their treatment at a polymetallic plant was 92.2% and 93.7%, respectively.

Sep 1, 2012

By Shuji Owada, Yang Geng, Natsuko Kuroki

Micro-bubble flotation is considered to be an ideal method for the separation of fine or ultra-fine particles, which are difficult to be separated with conventional flotation and other solid separation technologies. Micro-bubble flotation can increase the probability of bubble-particle collision more than conventional milli-bubble flotation. However, there are also some problems. For example, it is known that the rising velocity of micro-bubble is quite low; therefore, the flotation rate reduces. And also, the bubble-particle adhesion probability becomes lower than that of milli-bubble flotation, which is proved in our prior research. In this paper, we applied ultrasonic irradiation to the micro-bubble flotation system in order to solve the above problems and focused on the bubble-bubble and bubble-particle interactions. For clarifying the behavior of bubble-bubble interaction, bubbles behavior was recorded by high-speed camera under irradiation of various ultrasonic frequencies. As a result, in the case of bubble-bubble interaction, it is proved that bubbles are highly coalesced by ultrasonic irradiation especially in the lower frequency and it can enhance more precise separation. In the case of bubble-particle behavior, it is found that the floatability become higher with the ultrasonic irradiation of higher frequency, and it is indicated that ultrasonic irradiation might improve the bubble-particle adhesion probability. Additionally, it is also found that the apparent CMC of the micro-bubble flotation under the ultrasonic field become much lower with higher frequency than with lower frequency, and it is suggested that the dramatic improvement of hydrophobization is achieved.

Jan 1, 2014