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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 P. Somasundaran, Tarun Bhambhani, D. R. Nagaraj, P. Patra

"Certain non-sulfide gangue minerals are known to have a detrimental impact on flotation performance. When present in large amounts, they can negatively affect recoveries, grades and throughput at current operations, and dictate the viability and economics of a greenfield project. While the problem has been investigated for a long period of time, a scientific understanding of the mechanisms by which these minerals affect performance has not been obtained, and no acceptable solutions have been developed. This study focused on the role of physical aspects (e.g. shape, size and morphology) of these minerals as the underlying factors for poor performance. Flotation tests were conducted using model mineral systems to understand the impact of one phyllosilicate mineral (muscovite) on flotation kinetics, recoveries and grades. The study reveals that there is minimal impact on flotation kinetics, no impact on recoveries, but a very strong detrimental impact on concentrate grade. The traditional mechanisms of transport such as true flotation and entrainment are not sufficient in describing the extent of transport. The transport is attributed to the unique platy morphology of muscovite, which allows for action of buoyancy forces. Data also shows that the muscovite transport to the froth phase depends on particle size; coarser sized muscovite (100-150@) report to the froth phase in much larger amounts than medium sized muscovite (50-100@). At finer size fractions (<50@) the transport is also increased, and this is likely due to entrainment."

Jan 1, 2014

By J. B. Rubinstein

"The paper gives an overview of the history of flotation machine development. The laws of their evolution are stated and the place and role of column flotation are demonstrated.The major parameters of column cell diameter and height are discussed. Options are proposed for optimization of the hydrodynamic characteristics of large-capacity column cells. The high efficiency of columns with cell height of 4-6 m is demonstrated. The optimum parameters of multisectional column machines are determined. Their advantages compared to monocells are shown. A scaling-up procedure for column machines was developed based on flotation macro- and microhydrodynamics simulation."

Jan 1, 2003

By Nani Pajunen, Kari Heiskanen

"Products filling our societal needs, like communication and transportation needs, are becoming more sophisticated and efficient. The cost has been an increased complexity of material combinations. The same trend is also seen in investment goods. As an example, different crusher types have almost doubled the power to weight ratio in a relatively short time while producing even higher crushing rations. This has been possible by high performance materials and advanced designs. Another example is new hybrid materials in prefabricated high-strength steel structures in construction with the aim to lighten the products and obtain energy savings in the use phase e.g. in transportation. This development in general has made the end of life phase obscure. Recycling is often understood as the first phase of the material cycle. This has been supported by the material centric point of view. When, say indium, has been collected and mechanically treated to a concentrated fraction, it is assumed as recycled. This is not the case. The same applies to special steel alloys where one tends to lose some of the alloying elements to slag or even into the gas phase in the melting and refining stage, not in the earlier steps of recycling. At present there is no clear understanding of recycling of hybrid materials and no clear willingness to create new functional recycling systems. As the EU directives and most of legislation worldwide are based on the material centric thinking and implemented even on total mass recovery basis there is neither legislative incentive nor very strong economic incentives to work out the problem. In our research, we focus on industrial design towards sustainability from a product centric point of view from product collection to final metallurgical steps. It is vital, in the design phase of product, to understand the effects of decisions on recyclability to a saleable raw material. Main goal of our work is to create the fortunate circumstances in supply chain - to pass the barriers and find the effective and fruitful drivers - for reasonable use of raw materials and recycling co-operation with industry. The boundary conditions in the work are extractive metallurgical performance and the economic viability of all the steps. It can be shown from our work that small design alterations may have a large impact on the recyclability. The earlier the decisions are made in the product life chain the more positive impact they will have. It can also be shown, that a strong processing and metallurgical industry is vital to any meaningful recycling of the modern EoL products. Finally, it is also question of the individuals and values: supply and demand. Are you ready to take up the gauntlet: demand recyclable products."

Jan 1, 2014

By Elzbieta Mielczarski, Jerzy Mielczarski, Jan Drzymala, Yann Duvalm

Polyethylene glycol monoalkyl ethers (CnEm) render quartz hydrophobic while feldspar remains hydrophilic. As a result quartz can be separated from feldspar in small frothless flotation devices such as the Hallimond tube. The separation can be accomplished at room temperature at pH < 7 and C16E33 concentrations between 10-5 and 10-4 M for quartz particles smaller than 0.4 mm. No separation is observed when feldspar ore containing about 60 % of feldspar and 40% of quartz is subjected to flotation in a laboratory flotation machine. The reason for the lack of separation is a low hydrophobicity of quartz in the presence of polyethylene glycol monoalkyl ethers and high intensity of mixing in the flotation machine. The flotometric tests showed that the contact angle of quartz in monoalkyl ethers of polyethylene glycol solutions is less than about 18 degrees and depends on the structure and concentration of the ether and the pH of the system.

Jan 1, 2003

By M. L. Torem, R. H. Rojas, A. G. Merma

"Fine particle recovery by conventional flotation processes is very low mainly due to the low probability of bubble/particle collision and adhesion. In order to solve the problem of low particle recovery, several flotation technologies have been developed to increase bubble/particle collision efficiency. Among these technologies, the electroflotation process stands out. This process has advantages in the generation of microbubbles (<100 µm) and in the production of different amounts of hydrogen and oxygen microbubbles. These advantages favorably influence the fine particle floatability, due to the greater probability of particle/bubble collision and adhesion. The electroflotation tests were conducted for a hematite/sodium oleate system in a Partridge-Smith modified electroflotation binary cell of 0.38 L usable volume. The sodium oleate concentration, particle size, pH and current density were evaluated. Satisfactory results in the recovery of hematite were found at pH values of 7, reaching hematite floatability of 99% and 90% with hydrogen and oxygen bubbles, respectively.INTRODUCTIONThe flotation recovery of fine and ultrafine particles is normally very low and is caused by several factors, among them, the low probability of collision and adhesion bubble-particle, the difficulty to overcome the energy barrier (entrainment and entrapment), low selectivity, surface oxidation and mineralogical changes (Schulze et al., 1989; Waters et al., 2008; Shahbazi et al., 2010). This problem can be overcome by decreasing the bubble size or by increasing the apparent particle size. However, it is worth noting that the use of small bubbles or micro bubbles also involves some disadvantages such as their low momentum resulting in a slower process comparing with conventional flotation. Electroflotation is an attractive alternative for treating fine particles with small bubbles less than 100 µm, generated by the electrolysis of water. Electroflotation is one of the variants of the flotation process, where the gaseous phase is produced by electrolysis of an aqueous solution, generating oxygen and hydrogen bubbles (Sarkar, 2010; Gupta and Ali, 2012). These smaller size bubbles allow the recovery of fine particles by increasing the collision efficiency. This process is versatile and competitive in relation to other techniques such as dissolved air flotation and dispersed air flotation because the electroflotation units are smaller, more compact and require less maintenance and less operating cost than other flotation units (Zouboulis and Matis, 1995,). In addition, the electroflotation process is a clean technique and provides results in a short time, requiring only the investment in the electroflotation cell construction stage and the choice of the electrodes (Ketkar et al., 1991; Sarkar et al., 2010; Sun et al., 2011). In this sense, this study assesses the effect of pH, particle size and sodium oleate concentration on electroflotation of hematite fines."

Jan 1, 2018

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 T. C. Sun

Two wasted activated sludges (WAS), from an industrial wastewater treatment and a sewage treatment plant respectively, and 7 collectors are used to investigate the feasibility of air flotation thickening of WAS by adding the collectors used in mineral processing. The collectors experimented include straight chain fat acids with different chain length, sodium oleate, alkyl sodium sulphonate, sodium dedecylsulfonate, and dodecylamine. The results show that the thickening efficiency varied depending on different collectors. Of the collectors experimented, dodecanoic acid and dodecylamine are best collector for thickening both sludges.

Jan 1, 2014

By S. S. Indi, D. Santhiya, S. Subramanian, K. A. Natarajan

The interaction of sphalerite- and galena-adapted Bacillus polymyxa (B. polymyxa) cells with sphalerite and galena has been investigated through adsorption, electrokinetic and flotation studies. The amount of sphalerite-adapted cells adsorbed onto sphalerite and galena is found to decrease with increase in pH. On the other hand, the adsorption density of galena-adapted cells onto galena shows a feeble maximum around pH 8, and the amount adsorbed is marginally higher in the pH range of 8 . 11.5. In the case of sphalerite the amount adsorbed is higher in the pH range of 5 to 7. The adsorption density of both the adapted cells is higher for galena vis-à-vis sphalerite. Electrokinetic studies indicate significant surface chemical changes on the chosen sulphide minerals and the bacterial cells, consequent to microbe-mineral interactions. Selective flotation tests on a synthetic mixture of galena and sphalerite confirm that sphalerite could be preferentially floated from galena, using galena-adapted cells, but not with the sphalerite-adapted cells. The cells adapted to galena assay a higher polysaccharide content and are more hydrophilic, while the sphalerite-adapted cells have a higher protein content and possess greater hydrophobicity. Transmission electron microscopic studies have provided evidence in support of the differences between the cell surface characteristics of sphaleriteand galena-adapted cells. Possible mechanisms of interaction between the minerals and the bacterial cells are discussed.

Jan 1, 2003

By G. A. Wierink

This paper discusses a new method to increase flotation recovery. As known from literature, fine and coarse particles have different flotation rate constants, hydrodynamic behaviour and require different reagent regimes. The device discussed allows separate processing of finer and coarser slurry by extraction of a third stream, carrying finer slurry, from the flotation cell. By separate treatment of fine and coarse slurry operational conditions and so flotation recovery for both may be optimized more efficiently. Extraction and classification of the third stream is accomplished by low speed centrifugation and Taylor-Couette flow separation. This Dual Outlet Device (DOD) can be installed in a traditional flotation cell without need for equipment replacement. In order to asses different design options for the DOD a transparent laboratory scale model was built. For this scale model Computational Fluid Dynamics (CFD) simulations using the RANS k-e and LES turbulence models were performed. Essential insight in the dominant flow systems relevant to optimal operation of the DOD was obtained from the CFD simulations and flow visualization tests with the laboratory scale model. Based on these findings a number of configurations were investigated at pilot plant scale in a 5 m3 Outokumpu flotation cell. The results of the pilot plant study show that utilization of the DOD provides a method for in-cell control over particle size distribution in the slurry. Use of the DOD in a flotation cell may enhance flotation recovery and decrease flotation reagent consumption significantly, against marginal investment and operation costs.

Jan 1, 2014

By P. Saha, D. M. Chakrabarti, J. P. Srivastavam, P. Bhattacharyya, B. R. Sarkhel, Banerjeem B.

The phosphatic soil deposit at the Sukulu hills region of Uganda contains 10-12% P2O5. The ore occurs as a naturally degraded soil deposit containing a very sticky slime composed of earthy lateritic minerals. Desliming of the ore, which is imperative for its further beneficiation, is an extremely difficult hurdle to overcome for its commercial utilisation. Earlier studies on samples of the same ore at the National Metallurgical Laboratory (NML) and abroad established that it was necessary to pass the ore through a series of three stages of desliming, each consisting of a step of vigorous attrition scrubbing followed by hydrocycloning, for effective elimination of the sticky slime. In the present paper an innovative use of the very strong shear-fields created inside a hydrocyclone has been discussed, that could effectively eliminate the stubborn slime from the ore. The standard design of the hydrocyclone was suitably modified to increase the shearing effect on the slurry. It was possible, through the application of this modified hydrocyclone, to not only totally eliminate all the stages of attrition scrubbing, but also to reduce the subsequent stages of hydrocycloning. The modified technique yielded a concentrate of grade comparable to that obtained by employing the earlier more complex flow sheet, with about 25% higher P2O5 recovery.

Jan 1, 2003

By I. Govender, M. C. Richter, N. Mangadoddy

"We present an analysis of trajectory and time averaged data of near gravitational material (NGM) representative coal tracer particles within a magnetite medium passing through a 100mm diameter hydrocyclone imaged with PEPT (positron emission particle tracking) at iThemba labs, Cape Town. The tracking of neutrally buoyant tracers as well as the other NGM allows an empirical study of the approximate dynamical behaviours of both the dense medium as well as the range (size and density) of particles around the separator’s cut size within a partially imaged volume of the cyclone body lying within the field of view of the detector. The study was commissioned as part of a CFD validation study using empirical data from a real-world lab-appropriate system in order to shed light on the inner workings of hydrocyclones and their separation mechanisms. We employ various optimisation and noise reduction techniques within the analysis and follow a detailed investigation of the velocity fields derived from the raw spatial positions with an emphasis on the velocity profile within the forced and free vortex zones. Challenges encountered with this high velocity particle tracking experiment within a highly attenuating environment are also discussed. Various important velocity distributions are shown and compared to theoretical predictions. The power law decay profile of the free vortex and radial velocity scaling with regards to the Froude number are reproduced in line with the static particle approach. INTRODUCTION Cyclones have long been a vital industrial tool for the separation of different classes of particles. These cyclonic separators (with either gas or liquid medium) operate by forcing the solids-bearing fluid at high pressure into a cylindrical vessel causing high tangential velocity fluid rotation as well as, in the case of an “open” (with exit channels open to the atmosphere) cyclone, a central vortex air column spanning from underflow to overflow exit. The fluid is forced to exit the cyclone at two locations, the spigot and the vortex finder, generating the underflow and overflow respectively. The body of the cyclone usually terminates in a conical shape to focus the underflow stream. This geometry and large incident fluid velocity force high density materials toward the wall of the vessel where they are most likely to move along and down the inside wall away from the inlet to exit via the underflow while lower density materials traverse the cyclone body closer to the central vortex and are buffeted by the upward-moving column towards the overflow exit. This separation mechanism is selective of density and size in an interplay between the centrifugal force due to the rotation of the fluid and a drag force acting on the particles."

Jan 1, 2018

By Joseph Kelly, Christopher Kelsey

This revolutionary super-fine crusher has the unique capacity to generate fine and ultra-fine products from single stage reductions of coarse or fine mineral feeds. The crusher consists of a rotating compression chamber and an internal gyrating mandrel. The axis of rotation of the shell is displaced relative to the axis of the vertically mounted mandrel. The inner surface of the compression chamber is machined as double cone frustums at an angle equal to the displacement angle. Crusher feed is accelerated into a compacted particle bed, which lines the inside of the compression chamber. The depth of the compacted bed progressively increases until the mandrel is engaged. The mandrel is then free to rotate with the compression chamber. Continued feeding increases power draw and triggers the counter rotating mandrel gyration drive. The gyrating mandrel delivers multiple compressions at high pressure to the rotating particle bed. High concentrations of energy are harnessed within a small active volume over short retention times. The combination of extraordinarily high power intensity and extreme compressive force results in primary compressive fracture and induced secondary tensile failure. The axially displaced rotation of the compression chamber effectively distributes the breakage forces throughout the particle bed. This paper covers open circuit, pilot trials on magnetite, perlite, garnet, marble and a copper/pyrite concentrate. Particular emphasis is placed on the extraordinary results achieved with trials on zircon and highly refractory fly ash. The extreme duties were deliberately chosen to demonstrate the crusher’s application scope and potential to impact capital operating and maintenance costs as the technology matures. Super-fine crushing, once considered impracticable has the potential to offer compelling options for the generation of ultra-fine products.

Jan 1, 2014

By Vladimir Vigdergauz, Sergey Kondratiev

The paper reviews the existing criteria of the formation of particle-bubble aggregates during flotation. It is shown that predictions obtained by these criteria do not completely fit to the interaction between mineral particles and air bubbles. Experimental results of the studies into the influence exerted by molecular forms of collectors on the particle-bubble interaction are reported. Rate of dry spot expansion on the surface of pyrite with various combinations of chemically and physically adsorbed xanthate are examined. It is shown that molecular forms of collectors accelerate the rate of dry spot expansion on the mineral surface after the local rupture of the water film between particle and air bubble. The authors come to a conclusion that the molecular forms of collectors remove water from the interlayer between mineral particle and air bubble during their contact. Similarities of the proposed mechanism with the action of ion-molecular associates of fatty acids and amines are discussed. Reagents with high surface pressure and rate of spreading at the water-bubble interface are required for the effective interfacial dewatering. It is concluded that the value of surface pressure can serve as the criterion for efficiency of physically adsorbed reagents. The low surface pressure indicates weak collecting ability but high selectivity of the collector. Therefore, the presence of the molecular forms of collectors in the sorption layer is the necessary condition for formation of particle-bubble aggregates, and comparison of the surface tensions of collectors could be recommended as the estimation criterion of their flotation activity and selectivity.

Jan 1, 2014

By Vladimir Vigdergauz, Elena Belogub, Dmitriy Makarov

The influence of supergene oxidation on physicochemical and technological properties of polysulfide ores was studied. Modeling and analysis of oxidation pyrite copper-zinc ore samples from the Valentorskoye deposit show that sulfide floatability is decreased by the longer-term oxidation. The treatment of oxidized samples by sulfuric acid in oxidative conditions and its impact on the elemental sulfur composition on the surface of sulfides was discussed. It is shown that an enhancement of the floatability of sulfides of oxidized polysulfide ores after leaching by sulfuric acid could be perspective for the developing of combining floatation-hydrometallurgical technology of the nonferrous metals recovery.

Jan 1, 2014

By Erico Tabosa, Meng. Jun, Kym Runge, Matthew Brennan, Weiguo Xie, Dee Bradshaw

Turbulence and its distribution are of great importance in flotation cell design as they affect suspension of particles, air dispersion and particle-bubble collision rates, which in turn determine flotation performance. However, there is no mature technique to measure turbulence in three phase (liquid-solid-gas) systems such as in flotation cells. In this article, the authors present two new approaches that are suitable for measuring turbulence distribution in three phase systems and validate their applicability. The first technique uses a piezoelectric vibration sensor (PVS) to measure fluid kinetic energy standard deviation and the second technique applies electrical resistance tomography (ERT) to measure conductivity variation at a measurement position in a flotation cell. For the PVS technique, calibration of the sensor was performed to determine the values of parameters that were needed to calculate the force applied to the sensor. Then measurement was conducted in a 60L batch flotation cell and the results were compared with LDA measurement. This demonstrated that the piezoelectric sensor signal provides a good representation of fluid kinetic energy standard deviation at the position of measurement. For the ERT technique, conductivity distribution data was processed to give conductivity variations, which were then used to calculate fluid kinetic energy standard deviation at the measurement position. The spatial distribution of turbulence obtained by performing multiple measurements at different positions in the 60 litre batch flotation cell was found to agree with the PVS measurement results. These two techniques are potentially powerful tools for turbulence measurement in flotation environments, enabling a clearer understanding of turbulence’s influence on flotation performance to be determined.

Jan 1, 2014

By R. C. Miranda

This paper intends to demonstrate the applicability of tools for advanced process control and online particle size image analysis in crushing and autogenous grinding circuits. In a crushing plant, cameras are installed in the conveyor belts of the circuit products. The vision system continuously processes the acquired images and thus obtains the variation of the size distribution curve. From these measurements, the advanced control system can operate, for example, at the opening of the crusher, in order to keep the P80 in the desired range. In addition, through the power information and level of the crusher&apos;s chamber, it is possible to increase the capacity of the crushing circuit. If the crusher is not equipped with an automatic opening adjustment, a warning may be issued to the operator to provide this setting manually. In mineral processes that use autogenous and semi-autogenous grinding for fragmentation, obtaining online F80 through the vision system allows for manipulating the parameters of rotation speed and solids concentration, through which the amount of material at the critical particle size that is produced can be controlled. In addition, the noise produced in the mill can be measured and controlled. Thus, it is possible to prevent breaches and to optimise the mill capacity for grinding. Image analysis combined with an expert system that translates this information and acts to seek the most appropriate particle size distribution, brings greater stability to the process optimising the capacity of the equipment, which allows for significant gains in production.

Sep 1, 2012

By Häkkinen Antti, Salmimies Riina, Matveinen Maria

"Tailings generated during the upgrading of ore present a major challenge for the mineral processing industry. On one hand, the processing of tailings requires added capital input. On the other hand, increased difficulties in obtaining permits for dams and landfilling and increased costs associated with storage and tailings management also result in increased costs. To promote sustainability and make tailings management economical, added value must be generated from the waste material. This might be possible through the recovery of the metal values in the waste. This work discusses the possibilities of recovering metals from multimetal tailings through leaching in a stirred tank. The characteristics of the tailings are crucial and the distribution of the metals within the different size fractions is used to identify the most attractive route for the hydrometallurgical step. Leaching of nickel and copper is further investigated using acids at different concentrations. The leaching of base metals is possible at acidic conditions. Increased temperature and concentration of the leaching agent promote the dissolution of the metals, as could be expected. With simultaneous dissolution of several metals the dissolution mechanisms are difficult to identify. Furthermore, as several metals, not all of them being target elements, are leached another challenge arises from the selective recovery of those metals from the liquid phase."

Jan 1, 2014

By Avishan Atrafi

Frothing behavior of surfactants originate from their preferential adsorption at the gas-solution interface. Different surfactants may demonstrate different adsorption behaviors depending on their molecular structure and surface activity. The quantity and rate of adsorption of surfactants at the gas- solution interface in flotation systems will certainly affect kinetics of reaction and fractionation of surfactant between bulk and foam phase and subsequently their frothing characteristics. In this paper, the frothing characteristics of sodium oleate which is the main constituent of fatty acids used in flotation systems is explained. The adsorption behavior of sodium oleate is then compared to a typical non-ionic frother (Methyl Isobutyl Carbinol, MIBC) in terms of different adsorption behavior at the gas-solution interface. Since long chain fatty acids are weak electrolytes, their behavior is a strong function of pH. Also semi soluble salts including apatite contain considerable amounts of ions like calcium in their lattice, so the effect of presence of ions on the frothing behavior of fatty acids requires an investigation. A mass balance on the surfactant transferred to the foam was solved to estimate the bubble surface area flux in foam, which explained how the adsorbed surfactant at gas-solution interface controls the bubble surface area flux at foam. Since sodium oleate adsorption at foam takes place gradually, frother concentration as a function of time was monitored by the total organic carbon measurement (TOC) to compare the surfactant uptake rate at different concentrations, pH and ionic strength. The surfactant concentration adsorbed within foam together with the value of adsorption density from the Gibbs adsorption, leads to the calculation of the surface area flux and prediction of average bubble size in the foam at a specific time frame. This value was compared at different concentrations of sodium oleate. Dynamic surface tension measurements were accompanied to explain the adsorption behavior, though finally equilibrium surface tension turns out to better explain the foamability characteristics. Keywords: flotation collectors, flotation froths, foams, fatty acids, adsorption behavior

Sep 1, 2012

By E. Ashirbaeva

"Ores of ferrous metals traditionally make up the bulk of recoverable reserves of solid minerals, and iron ore concentrates - in the processing and consumption. To obtain concentrates, three main methods are used: dry and wet magnetic separation, gravity and flotation. But even their integration into complex developed schemes with finishing operations often do not solve the problem of obtaining high-quality concentrates, which are necessary for powder metallurgy and electric steelmaking. Increasing the iron content in the concentrate by removing harmful impurities is the goal of this work. The possibility of reducing the operations of wet magnetic separation twice and completely eliminating concentrating operations in ball mills from the scheme of operations has been established. Selective leaching agents for each type of iron ores have been created, allowing to obtain concentrates with an iron content of not less than 68-69% and negligible concentrations of harmful impurities. Methodical recommendations for long-term storage of bioreagents in the active state, their immobilization and preparation in industrial conditions at the enterprise Nedropolzovatelja are developed. The proposed biotechnology, which allows to obtain high quality iron and conditional concentrates for harmful impurities, is protected by patents (RU 2537684 ""Method for fine-tuning of high-sulfur magnetite concentrate"" for magnetite ores and Pat. RU 2599068. For the industrial implementation of the new technology, organizational and technological measures have been developed in the system with Road maps for types of ores. The developed technology makes it possible to condition noble metal, tin, tungsten, nickel and other concentrates in harmful impurities such as arsenic, antimony, mercury, sulfur, copper, zinc, iron, phosphorus, manganese, in total 30 components that pass into solution under the influence of bioreagents.INTRODUCTION Consumption of various metals is steadily increasing every year, the volume of mining is constantly increasing. Ores of ferrous metals traditionally make up the bulk of the recoverable reserves of solid minerals. Enrichment technologies for iron-containing ores are reduced to the combination of three main methods: wet and dry magnetic separation, gravity and flotation. But even the use of complex advanced technological schemes often does not lead to the production of high-quality concentrates suitable for metallurgical processing. In this case, either lapping operations or effective technical and technological solutions are used in the main enrichment cycle. Widely used in practice methods for improving the quality of iron ore concentrates include the use of finishing operations (fine screening, reverse cation flotation), staging of concentrates, the use of more sophisticated equipment (separators with running magnetic field, magnetic gravity classifiers, column flotation machines)."

Jan 1, 2018