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By Cagri Emer

In conventional mechanical flotation cells, when the size of particles exceed a particular value, that is of the order of 100 µm for metal sulphides, the recovery of particles decline rapidly. It appears that the turbulence in the agitated vessel is sufficiently intense to rupture the forces of attraction between the particles and the bubbles, so the large particles are flung off the bubbles in the turbulent field. It has recently been suggested, that a fluidized bed would be a very favorable environment in which to contact bubbles and the particles. In a fluidized bed, particles are supported by rising flow of fluid, which separates them from each other and allows them to move freely while remaining close together. In this novel method, bubbles injected into the fluidized bed are able to rise through it, colliding with hydrophobic particles, transporting them to the top of the column where they can form a froth layer that overflows into a launder. The flow in a fluidized bed is generally slow and nonturbulent, and preliminary experiments have shown, that it is possible to collect mineral particles as large as 1 mm and coal particles as large as 5.5 mm. If the upper particle size limit can be extended, there could be significant reductions in the overall energy consumption in concentrators. Calculations show for example that if the top size for flotation could be increased from 100 µm to 400 µm, there would be a reduction in grinding energy of the order of 40%. It is therefore, important to study the mechanism of coarse particle capture in fluidized beds. In this work, the factors governing the capture rate of particles, particularly the particle and bubble size, the fluidization velocity and the superficial gas velocity have been investigated, and the results will be presented.

Sep 1, 2012

By P. Somasundaran

Gangue minerals can often have severe adverse effects on selective value mineral separation. Such effects can be mediated through a variety of pathways or mechanisms. One popular mechanism is that of ?slime coating? or heterocoagulation, wherein the gangue mineral fines are believed to coat the value mineral surfaces and thereby reduce selectivity and floatability. Another pathway that has received relatively little attention is that mediated through the effect of gangue minerals on pulp rheology, and consequently selective separation. Our recent work in developing a scientific understanding of these effects has highlighted the prevalence and importance of this pathway. In this study, the impact of shape and morphology of serpentine gangue minerals on suspension rheology and selective Ni flotation from ultramafic ores was investigated. We found strong evidence for micro- and macro-network formation in the presence of acicular (needle-shaped) or fibrous minerals, which impacted pulp rheological properties. Results also supported the hypothesis that morphology has a greater role to play than mere shape. The size of the network ranged from 5 microns to 2 cm depending upon the amount and aspect ratio of fibrous minerals. These networks impede many flotation sub-processes, such as gas dispersion and bubble-particle interactions. Additionally, the small pore size of the networks prevents bubble penetration leading to a large transport of the gangue minerals to the concentrate via lifting of the entire network by bubble flux, which resulted in a significant grade dilution. Based on the scientific insights generated in this study various techniques have been developed to improve selective value mineral separation. Keywords: fibers, aspect ratio, microstructures, networks, pulp viscosity, gangue transport

Sep 1, 2012

By S. Gaydardzhiev

Laboratory batch tests having preliminary and orientation character aiming at improvement of the molybdenum flotation at Ellatzite copper processing plant in Bulgaria have been conducted. The following technological parameters have been screened to study their influence on the grade and recovery of copper and molybdenum during the rougher flotation stage: flotation pulp density, pH, addition of secondary collector and replacement of MIBC by pine oil as a frother. The results have shown that slightly better grade/recovery figures could be obtained for both copper and molybdenum at lower flotation pulp densities. The addition of kerosene has improved the recovery of molybdenum however, on the expense of that of copper. The effects from pH variation and the replacement of MIBC by pine oil as a frother have been almost negligible.

Sep 1, 2012

By M. Ito

The authors have developed the RETAC jig (a modified TACUB jig) and have reported that the RETAC jig can separate relatively low density particles such as plastics. To further improve the separation ability, a hybrid jig (a RETAC jig with an air bubbler under the particle bed), which can separate plastics having similar specific gravities by the differences in the wettabilities of the particles was developed. Surface modification of plastics with similar wettability enabling separation in the hybrid jig and the effects of wettability control of the plastics using reagents are reported.

Sep 1, 2012

By A. Kuriwada

Dolomite is a mineral, which consists of CaCO3 and MgCO3. In this work, a series of experiments were carried out in order to adsorb boron from a boron-containing solution using a calcinated dolomite sample, and then to desorb it from the loaded adsorbent. A particular modification on the surface of dolomite was observed when it was thermally treated at certain temperature, ranging from 750 oC to 1050 oC; in turn, it is the specific surface was increased. In other words, the experimental results suggested that the calcinated dolomite exhibited a high adsorption capacity for boron, indicating its effectiveness in effectively adsorbing boron from drinking water or wastewater.

Sep 1, 2012

By M. Naymanbayev

The characteristics of the mineral composition of ores and valuable set of components: the technology of processing depending on the type of mineralization, the nature of the impregnation of ore minerals and their composition have been considered. There have been given technological schemes for processing concrete objects. The analysis of fitness fields for industrial development (degree of scrutiny, the effectiveness of developed enrichment and hydrometallurgy technology) has been provided.

Sep 1, 2012

By P. Basarova

The attachment of bubbles onto a collecting surface is an ubiquitous natural phenomenon, playing a critical role in numerous practical processes. The goal of the project is to broaden the knowledge about hydrodynamic interactions between small bubbles and large solids that occur in nature and industrial processes. Focusing on collision processes between a single rising bubble (Db<1 mm) and a larger falling spherical particle in stagnant liquid, the theoretical model describing the bubble trajectory is given here. The model is based on analysis of forces acting on the bubble, and utilizes equation for the bubble motion. Mobile and immobile type of bubble surface mobility are considered. The calculated results are compared with the experimental data; here a high-speed video camera was used to capture the bubble motion and bubble-particle interaction. Very good agreement between experimental and calculated data was found. For both types of surface mobilities, the bubble deviation in the horizontal direction is nearly linear. The proportion constant is bigger for immobile bubble surface and increases with the bubble size. Furthermore, particular forces acting on bubble were studied. A similar course of relative bubble velocity and force impact was observed for identical bubble position. For cases when the bubble centre is close to the particle axis, only deflection in one direction is observed. When the bubble is reaching the maximum trajectory, the force ratio is changed. The bubble is firstly pushed away from the particle, but when it is within close distance from the particle, the bubble is pushed towards the particle.

Sep 1, 2012

By Peter J. Scales

The recovery of water for re-use in minerals processing is an important issue in the reduction of water use in mining, as is the dewatering of tailings to reduce the propensity of ?wet? tailings dams. It is common in these dewatering operations to use thickeners whereby polymeric flocculants are combined with the dilute feed to the thickener to aid sedimentation and the subsequent consolidation of particulate materials. Thickeners are the workhorses of water recovery and tailings dewatering and although the basics are well understood, there is still no ability to reliably predict the throughput and underflow density from a thickener based on traditional sedimentation tests and flux analysis. The reasons for the discrepancy between full-scale operations and predictions based on laboratory tests are numerous, including difficulties in mimicking the flocculation conditions experienced in the field and the shear conditions in the thickener. The latter effects are little understood and hard to quantify and include effects due to flocculated aggregate densification, complimentary shear and compressional effects and aggregate break-up. Developing a set of test protocols to quantify the effects of densification, shear in compression effects and aggregate breakup and the subsequent contributions of each to compressional dewatering in a thickening environment has been completed for a simple model polymer flocculated particulate suspension. The data and analysis shows that aggregate densification is a dominant contributor to the difference between observed and predicted behavior based on laboratory tests. A major consideration in the analysis is the fact that common thickener operations are permeability limited and although the various effects are all important, the one that results in the fastest water release is dominant. Of interest also are the shear rate, concentration, and time dependence of the aggregate densification process. A basic model of the process has been developed along with network yielding tests conducted using rheometry. Keywords: compressional dewatering, gravity thickening, rheometry, aggregate densification, raked batch settling

Sep 1, 2012

By Kyle Bartholomew, Robert McIvor

"Functional performance analysis of closed circuit grinding provides valuable insight into the two components of ball mill circuit grinding efficiency: classification system efficiency and mill grinding efficiency. Classification system efficiency isolates the combined effect of classifier performance and circulating load ratio from other circuit variables, such as ore grindability and the mill grinding environment. Optimization of classification system efficiency ensures grinding energy is applied to particles needing further size reduction and not to overgrinding. Entirely based on size distribution data, classification system efficiency precisely distinguishes subtle changes in classification system performance. Use of the functional performance equation to isolate mill grinding efficiency allows for proper optimization of the mill grinding environment by isolating confounding effects of changes in classification and ore grindability. Variables such as mill percent solids and grinding media selection can be optimized using the mill grinding efficiency subcomponent of functional performance. First published by McIvor in 1988, the functional performance equation provides a set of standardized, quantitative optimization criteria, simple and powerful, which link circuit performance to plant design and operating variables that can be manipulated. Functional performance optimization has been applied in numerous mineral processing plants globally and continues to gain acceptance as a practical means for grinding circuit optimization. In this paper, examples of derivation and industrial application demonstrate the means by which functional performance analysis dissects grinding circuit efficiency into its subcomponents allowing the reader to apply this straightforward, powerful optimization methodology at their mineral processing operation."

Jan 1, 2014

By D. G. Hulbert

"Mineral processes are complex operations that have been modelled, controlled and simulated by diverse technologies. A review is given of some models of mineral processes in the literature. A new variation of a dynamic process model of flotation is presented. Process models, describing real and relevant physical variables, give a good understanding and good qualitative simulations, but can sometimes require prohibitively difficult and extensive parameter estimations. Process control is usually best done on operational plants by the fitting of system models, which can home in on the plant?s observability, controllability and optimisation. System models can be of a form amenable for use in appropriate techniques for controller design and implementation. The control of milling circuits is discussed in some detail. While simulators use models to predict dynamic or steady-state information, part of their strength lies in their ease of use and their ability to test different types of specifications. Some results are given for a flotation circuit simulator that can be made to solve virtually any permutation of specifications.INTRODUCTIONThe development and application of appropriate technology can lead to better operation of mineral processing plants in industry, so that substantial benefits can be obtained from improved throughputs, efficiencies and product qualities. This paper addresses some of the principles and methods used in the quest for the development and exploitation of such technology. Although the design of processes is often the motivation for modelling and simulation, this paper also targets the use of modelling and simulation for the control and optimum operation of mineral processes. The two processes given the most attention here are flotation and milling.Technologies used in mineral processing range from simple to very complex. Simple technical principles, such as mass and component balances, can yield some simple and effective strategies for modelling and control. However, minerals in particulate form have such complex physical and chemical properties that there appears no end to the complexity that emerges, as more and more factors are taken into consideration in the pursuit of better results and understanding. The situation is aggravated by the complexity of mineral processing plants, which have spatially variable conditions within process units, and complicated interactions between these units."

Jan 1, 2003

By B. Rath

An effective process plan is an important part of maintaining consistent recoveries in mineral processing operations. Traditionally, Mineralogical studies are completed using chemical and metallurgical methods to monitor recovery and elemental distribution. The development of mineralogy and more efficient processes in mineral analysis techniques means that mineralogy is now more accessible as an efficient and comprehensive study tool. As operating costs increase and feed grades decrease it is important to maintain tight control of process and ensured maximum recovery is maintained at all times. Just a few days of losses in recovery caused by changes in ore type or processing conditions can have a large effect on total metal recovery and profit. Mineralogical audits can be used to minimize these losses by monitoring the fundamental behavior of feed ore on a regular basis. Smart use of mineralogical studies can develop mineralogical and ore type benchmarks in a detailed, which can be used in process control and monitoring. Geological ore types can be used to identify key mineralogical parameters that may be used in routine and cost effective analysis. Mineralogical systems ideally suited to this because of the depth of information on everything from modal mineralogy to locking/liberation characteristics and mineral associations. Mineralogical studies can equally be applied to specific unit operations within the process, which can allow more detailed information to be gathered on areas of the process that have been identified as critical. This will be especially effective for flotation or oxidation processes where process parameters can be very sensitive to small changes in mineralogy. This paper deals with the Ore Morphology, Ore Mineralogy, Gangue mineralogy, Photo micrographs under reflected, transmitted light and XRD studies Ore, Mineral studies of Sub grade Iron ore of Bacheli Complex, Bailadila Sector, India. Keywords: mineralogy, liberation, liberation studies, ore mineral, gangue mineral, morphology, jasper, ferruginous clay

Sep 1, 2012

By Cesar Gomez, Jaime Álvarez, Lisette Wen

Laboratory mechanical flotation cells are extensively used in mineral processing for running batch flotation tests with a variety of purposes, for example assessing feed characteristics, determining flotation kinetics, or testing of new reagents and procedures. It is known that the results obtained depend on the operation mode, self-aerated or forced-air, and on the operating conditions selected for the test, in particular impeller speed and gas flow rate. These different results are a consequence of changes in size distribution of the generated bubble population and its remarkable evolution when frother is added; variations in bubble size affect the bubble surface area flux (BSAF), a variable which correlates with particle collection. Results of a two-phase (air-water) test program designed to measure bubble size for a variety of combinations of impeller type and speed, gas flow rate, frother type and concentration, and cell volume, demonstrated the wide range of BSAF with which the cell can be operated. The results obtained in this work demonstrated that gas dispersion in a forced-air lab flotation machine is significantly affected by the characteristics of the impeller/cell geometry combination in use, and the operating conditions selected. Operating conditions must be carefully selected and maintained during the test to ensure consistent results, in particular when frother concentrations below 20 ppm are used, because frother concentration in the cell will decrease as flotation progresses as a consequence of frother partitioning to the concentrate.

Jan 1, 2014

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

Dielectrophoresis is a separation technique that uses a non-uniform electrical field to separate particles on the basis of their permittivity. There are many areas of mineral processing that might benefit from the application of dielectrophoresis. These include: coarse removal of gangue, recovery of ultrafine particles, upgrading of flotation concentrates or simply as a laboratory analysis technique. In order to determine the potential value of dielectrophoresis to the mineral processing industry, the response of composite particles was investigated. The electrical properties of composites involve complex relationships between the shape, distribution and permittivity of the individual grains within the rock. The relationship between mineral composition and dielectrophoretic force was measured on single particles from two ore types. The results were used to populate a model that could predict the separation characteristics of the ore. The insights gained from this model separator allowed potential applications of the technology to be examined and their performance evaluated.

Sep 1, 2012

By Y. H. Tang, H. Y. Zhang

"Tailings from lead-zinc mine contain plenty of dolomite and low-grade fine-grained barite, which is difficult to enrich by mineral processing. Since the density of barite and dolomite has some differences due to the fine dissemination size in a complex sedimentary, the gravity separation tests were conducted with no results obtained. The magnetic separation was conducted to remove the magnetic gangues, and the results were not satisfactory because of the gangue minerals such as limonite and others were low in content. The results of floatation tests showed that the mineral separation of barite and dolomite is quite difficult because that they have similar mineral floatability. Experimental research shows that the good results can be obtained by “desulfurizationbarite floatation” processing with the new depressant TS. The barite concentrate containing BaSO4 91.27%, BaSO4recovery is 70.25% when sodium dodecyl sulfonate serves as a collector and TS as the depressant.INTRODUCTIONBarite is an important mineral material. Often associated with other minerals, it usually needs to be separated by mineral processing in order to meet the application requirements. The main barite beneficiation methods include hand sorting, gravity separation, floatation, magnetic separation, acid leaching, etc. Usually barite associated with oxide ore such as fluorite dolomite, quartz ore etc. are also associated with sulfide ore such as pyrite, sphalerite and galena. The separation between barite and sulfide ore (such as pyrite) is easy. On the other hand, the separation between barite and oxide ore (such as dolomite and fluorite) is very difficult. There are quite a lot of reports on the separation between barite with fluorite dolomite however the separation between barite and dolomite is seldom discussed.The ore properties are quite complex attributable to mineral assemblage containing a large amounts of dolomite. As the density of barite and dolomite has some differences, gravity separation between them is usually easy. The gravity separation tests were conducted with no results obtained due to the fine dissemination size in a complex sedimentary. The magnetic separation was conducted to remove the magnetic gangues, and the results are not satisfactory as the gangue minerals such as limonite and others were low in content. Due to the fine dissemination and intimate association of minerals, and barite and dolomite contain the same group ions of Ba2+, Ca2+ and Mg2+, the results of flotation tests showed that the mineral separation between barite and dolomite by flotation means problematic. Previous studies have been conducted by several institutions but none to date has come up with a satisfactory process in dealing with the deposit. This may be attributable to: high cost of reagents; unsatisfactory performance. Therefore, the key to the flotation separation of barite and dolomite is the application of selective inhibitors. Based on previous test observations and years of extensive research experience in barite processing technology, with the new depressant TS has selectivity inhibition on dolomite developed and used, good results can be obtained by “desulfurization-barite flotation”, which allows barite in the lead-zinc tailings to a comprehensive recovery."

Jan 1, 2018

By T. Mütze

The progress in comminution is often described by the specific surface area and the energy utilization or the brakeage ratio and breakage function. The principal mechanisms of size reduction are therefore, well known. All four parameters share a common disadvantage: They are limited in describing the behavior of a feed material with fine particles and a wide particle size distribution. An alternative is to describe the progress in comminution with ? The particle size distributions Q(x) before and after the stress or ? The particle concentration ratio pcr(x), which combines these two states. In the case of a self-similar fracture behavior, (in short: self-similarity) the progress in comminution can be simplistically described by the relationship between a reference particle size and the stress intensity. Self-similarity means self-similar breakage functions of geometrically similar particles of the same strength, a certain stress situation and stresses up to the breakage point. Self-similar breakage functions show the same curve at different stress intensities when the fragment size x is normalized with a reference particle size xNorm. This behavior was demonstrated for single particle comminution repeatedly and unequivocally. In the field of particle bed comminution, these results differ in literature. Therefore, the self-similarity in particle bed comminution was systematically investigated at the Institute of Mechanical Process Engineering and Mineral Processing of the TU Bergakademie Freiberg as part of a research project. Limestone, quartz, silicon carbide and glass beads, were examined with a hydraulic press. The particle sizes covered monodisperse fractions in the range of 1-1000 µm, bimodal mixtures of these fractions and polydisperse fractions. The results obviously show that there is no self-similar fracture behavior in the case of glass beads, quartz and silicon carbide. Statements on the self-similarity of limestone are much more difficult: Only some of the investigated limestone fractions show a similar clear, non-self-similar behavior. Self-similar curves appear particularly for fine monodisperse fractions as well as bimodal mixtures, which stressed with pressures above 200 MPa. Considering the measurement accuracy of particle size analysis the coincidence of the curves can be explained by the fact that progress in comminution almost ends above 200 MPa. At this point, a hydrostatic stress state is reached in the particle bed which is known from the literature. This stress state inhibits further fractures. Overall, it has been verified for the investigated materials that there?s no self-similar fracture behavior in particle bed comminution. One reason for the diverse opinions in literature is that there are three types of particles after the comminution in the particle bed: ? Particles which are stressed below their breaking point, ? Particles which are stressed right up to the break point, and ? Particles which are stressed beyond their breaking point.

Sep 1, 2012

By Z. Chen

This study is concerned with the behavior of bubble clusters in a well-controlled turbulent flow. We used a specially designed cell where the bubble aggregates could be formed and exposed to breakage by a rotating impeller. The effects of impeller speed and the concentration of collector on cluster behavior were studied. It was found that the size of the clusters increases with the concentration of collector used. We also found that although the clusters could easily be destroyed under the action of impeller, they could reform, especially at lower impeller speeds. It was observed that the size of the bubbles arriving into the impeller region in the absence of particles before breakage was considerably higher than the size of the clusters formed at the same impeller speed. It appears that both cluster breakage and re-formation take place simultaneously, and the extent of formation and regrowth is mainly determined by the hydrophobicity of the particles and the impeller speed.

Sep 1, 2012

By D. Kosior

Influence of frothers (a-terpineol and n-octanol) concentration on kinetics of a three phase contact (TPC) formation by a bubble colliding with a hydrophobic surface (Teflon) of different roughness was studied using a high-speed camera (1040 frames per second). It was found that the Teflon surface roughness and the frother concentration strongly affected time of the TPC formation (tTPC) and time of drainage (tD) of the liquid film separating the colliding bubble from the solid surfaces. With increasing Teflon surface roughness, from ca 1 to 80 µm, the time of the TPC formation was shortened by over the order of magnitude, from ca 100 to a few milliseconds only. At low a-terpineol and n-octanol concentrations, thetTPC values were shorter than in distilled water due to lowering the bubble velocity in the frother presence and diminished bouncing of the colliding bubble. However, at high frothers concentrations the tTPC values were prolonged, despite that the bubble velocity was similar. The prolongation of the tTPC at high frother concentrations indicates that air (micro- and/or nano-bubbles) was present at the Teflon surfaces of different roughness. The mechanism of the tTPCprolongation at high frother dosage is described.

Sep 1, 2012

By I. Zh. Bunin, G. K. Khachatryan, N. E. Anashkina

For optimization of diamond processing technology the influence of nanosecond high voltage pulses on mechanical and technological properties of diamond crystals and kimberlite rock-forming minerals (calcite, olivine, serpentine) was investigated. Using methods of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), microscopy and mikrohardness measurement the changes of structural, physic-chemical surface properties, and microhardness of minerals as the result of impacts, was studied. Non-thermal impacts caused a decrease of kimberlite rock-forming minerals microhardness in general to 40-66% as the result of surface microstructure destruction which is caused by formation of micro cracks, traces of surface breakdown and other defects. At the same time, the pulse energy impact on natural diamonds led to formation of B2 type crystal lattice microsift defects, elevated concentration of which increases the hardness properties of crystals. The obtained result indicates possibility of applying pulsed energy effects to improve the softening efficiency of diamond-bearing kimberlites rock-forming minerals without damaging the diamond crystals and ensuring their preservation by the subsequent grinding of ores. By IR and X-ray photoelectron spectroscopy revealed that processing by hight voltage pulses causes a change of natural and synthetic diamonds surface functional cover composition. Short-term exposure (~ 10 - 30) leads to detachment and partial destruction of secondary phases mineral films on the surface of natural technical diamonds, increasing floatability and hydrophobicity of crystals. However, with increasing duration of treatment (~ 30 - 150) occurs surface hydroxylation (found by XPS for synthetic diamonds), as a result of diamond surface layer oxidation. The effect of increasing the natural diamonds flotation activity by 14% (from 47% to 61%) was experimentally established as a result of processing diamond crystals with nanosecond pulses (~ 10-50 sec), which indicates the principal possibility of using pulsed energy impacts to intensify the diamond flotation during processing diamond-bearing kimberlites.

Jan 1, 2018

By l. Bokányi

The Tóth adsorption isotherm-model was derived and has been widely used for the inhomogeneous solid surfaces. The three-parameter isotherm incorporates the effect of the interaction between the adsorbed substances as well. All classic isotherms can be clearly derived from this one. Bio sorption is the sequestering of dissolved components, i.e. metals from aqueous environment by living or dead biomass. The mechanism of the bio sorption is rather complex and predominantly refers to the affinity of the chemical functional groups: acetoamido groups of chitin, structural polysaccharides, amino and phosphate groups in nucleic acids, amino, amido sulfhydryl and carboxyl groups in proteins, hydroxyls in polysaccharides, sulphates, etc. towards the soluted substances, i.e. heavy metal ions. The physisorption, as well as the micro precipitation also play a role in the bio sorption mechanism. The description of such a complex process can be done by a model reflecting this complexity. According to our experimental results obtained using algae and immobilised algae for the sorption of heavy metal cations, the most appropriate model for such a description is the Tóth-isotherm, the parameters of which can be interpreted. Flotation process is also a very complex one, the overall result of which depends on the partial results of many micro processes and parameters. The particle interaction which very often takes place in the flotation systems makes the phenomenon even more complex. The flotation kinetic model with particle interaction was already introduced by author in 1994 and further developed in 2000. In this paper based on the experimental results obtained with metallic particles in case of recycling flotation the applicability of the Tóth-equation as an alternative flotation kinetic model for the systems with particle interaction is proved. The applicability of Tóth-model in mineral processing demonstrates again its universal character and the great talent of the late József Tóth, great Hungarian chemist. Keywords : Toth isotherm, biosorption, Langmuir, Freundlich

Sep 1, 2012