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By V. K. Gupta

Selection of mill size for reducing a feed material of a given size to the desired product size is generally based on the specific energy estimate obtained from Bond test. Over the last thirty years or so, an attempt has been made to develop a more accurate and powerful alternative approach based on the characterization of the particle breakage kinetics and material transport through the mill over a range of operating conditions of interest and correlating the degree of size reduction achieved with the net specific energy input to the mill. Particle breakage kinetics are described in terms of the specific grinding rate and breakage distribution parameters for the individual size fractions. Precise estimates of these parameters and the net energy input to the test ball mill (a laboratory or pilot scale mill) are important for development of desired energy-size correlations. In this context, three tasks are important: (a) preparation of the feed charge, (b) design of batch grinding experiments and (c) computational technique used for estimation of the breakage rate and breakage distribution parameters. This paper highlights several aspects of these three tasks that have been overlooked by researchers working in this field, and describes a more appropriate approach for estimation of model parameters and specific energy input. Several examples are included based on the data available in the literature and those generated in our laboratories to illustrate important points.

Sep 1, 2012

By Alain Broussaud

The lecture is about the growing role and the evolution of advanced process control (APC) in the mining and mineral processing industry, taking into account major trends in Information Technology. It reflects the standpoint of a team, which has already successfully developed APC technology for more than 20 years. Advanced process control systems tend to rely on combinations of artificial intelligence techniques or algorithms that complement each other and cooperate. Each technique or algorithm makes it possible to use certain type of knowledge about the process, so that the advanced control systems benefit at any time from the combined knowledge of process and control engineers and plant operators, from knowledge derived from past research work and process modeling, from a considerable amount of data provided by advanced instrumentation in real time, and from knowledge that can be extracted automatically and at any time from past data and images. The lecture will first review and compare the role, merits and limitations of algorithms that are used for online decision making in mineral processing plants: expert systems, fuzzy logic, neural networks, soft sensors, optimizers, and MPC controllers. The lecture will also review the role of online image analysis and sound analysis in process control. Recent developments in this area open new dimensions, in particular the ability for advanced process control algorithms to automatically explore the past, move back and forth in time in order to make better informed decisions, and the ability to cooperate with the operators for better performance. Applications will be presented. Recent progress in process simulation makes it possible to design, configure, check, and pre-tune APC systems before plant startup, opening new options for implementing APC. In conclusion, the author will share his experience about the key ingredients for sustainable success in APC Keywords: mineral processing plants, APC, MOC controllers

Sep 1, 2012

The Indian steel industry is growing at a rapid pace and expected to be the 2nd largest steel producer in the world after China. To cope up with this growth and to sustain it, the industry needs to focus on effective utilization of domestic metallurgical coals. While the importance of indigenous coal has increased, its supply from the domestic sources is declining. This is primarily due to high ash content in Indian coals leading to its difficulty in washing to a low level competitive to imported coals. Non-availability of a suitable beneficiation technology to bring down the ash to such a low level is the other reason. Effective utilization of current technologies has enabled Tata Steel to bring down the ash to 13-16% from its captive collieries. However, further lowering the ash using the conventional beneficiation technologies is difficult and unsustainable. New technologies should be developed for bringing down the ash further. A thrust area research program has been undertaken at Tata Steel for producing clean coal with 8% ash maintaining the yield currently achieved in its washeries. The technologies attempted are based on chemical beneficiation of coal. In leaching process, suitable chemicals are used for extracting ash minerals from the coal. As an alternative process, the combustible part of the coal is being extracted using a suitable organic solvent through an organo-refining process. Both the processes have been successfully developed in the laboratory and are being demonstrated in pilot scales. Various beneficiation processes practiced at Tata Steel including the efforts made for developing new processes for achieving clean coal with 8% ash have been discussed in this paper. Keywords: metallurgical coals, washing, beneficiation technologies, chemical beneficiation, leaching, solvent, and organo-refining process

Sep 1, 2012

By Shenxu Bao, Ying Bian, Xiang Liu, Liuyi Ren, Yimin Zhang, Chun Liu

Efficient enrichment of high-carbon low-grade mica stone coal containing vanadium is a key problem in the mineral processing field, and the mature beneficiation process is yet to be developed and applied. In this paper, a special mineral mica type of stone coal containing vanadium from Tongshan, Hubei Province, China was selected as the research object. Chemical analysis results show that this mineral contains V2O5 0.71%, SiO2 49.28%, C 13.44%, and CaO 6.26%. Scanning electron microscope (SEM) shows that vanadium generally exists in all kinds of mica minerals in 20 µm to 50 µm fractions. Mica stone coal containing vanadium must be ground to a particular fineness (approximately 45 µm). To reduce acid consumption during vanadium extraction from stone coal through acid leaching, a pretreatment process was proposed to enrich micas by using shaking table and flotation methods. A new combined technology process was implemented, resulting in a 0.96% improvement in the vanadium grade of raw materials in the succeeding process. Vanadium losses were controlled to 4.57% through the pre-concentration process, which reduced the burden of the subsequent procedure. The content of high acid consuming minerals was also diminished, such that approximately 6612 CNY was saved from producing 1 t V2O5. Therefore, stone coal containing vanadium should be pre-concentrated by using an appropriate combined process to reduce costs.

Jan 1, 2014

By Sergey Ulianov, Arkady Senchenko, Alexey Shvets, Arkady Bakotin

"This paper contains description of research results of technology development for copper recovery from weathered tails of iron processing plant. The predominant host mineral that contains valuable component is chalcopyrite occurring in its free form and in associations with ore and rock-forming minerals. Copper grade is 0.26-0.30%. Emulsion inclusions of chalcopyrite in pyrite and sphalerite were noted. Major problem is low copper recovery (30-35%) by flotation. When studying chalcopyrite in primary concentrate it was determined that the surfaces of many chalcopyrite grains are covered with oxide films which prevented collector attachment onto them. Second issue was deep association of chalcopyrite with pyrite and sphalerite. Sulfidizing reagent addition did not help to reach the required level of copper recovery to concentrate. In the result of research performed the technological flowsheet was developed including preliminary treatment of head material in a special unit aiming at oxide films removal, followed by copper rougher flotation on head size tails, crude concentrate regrinding and a number of cleaner flotation operations. After the treatment of weathered tails according to the flowsheet developed, copper recovery to flotation concentrate became 71.53%, at 23.46% copper grade. The suggested technology allows one to solve the issue with treatment of technology-related copper-containing stockpile material, as well as to include the ores where copper is represented by sulfide minerals covered with oxide films into processing."

Jan 1, 2014

By Hemant Nerurkar

The destination of human development journey is envisioned as human well being. Human well-being is the extent to which individual share the ability and the opportunity to live the kinds of lives they value it includes environmental security, good health and living conditions, all of which are closely related to each other. The breakthroughs, which transformed the human race, have close interdependency with the environment. With the increase in world population, the requirement of natural resources is increasing every day. The nature is still stronger than man is but we must use natural resources more responsibly. The key to our well being is sustainable development Development effort for human well being may have adverse impact on the environment also. To keep the net impact positive is critical for sustainable development. For mineral processing industry, the value of a mineral is in the actual value as perceived by the end user. The process designs, investments in technology development all have direct relationship with the value of use and making a net positive impact on our ecosystem The value proposition has shifted towards raw materials and is a big differentiator. The availability of good quality raw material is difficult or is available at a premium. The challenge today is to develop green technologies that make effective and efficient usage of low grade raw materials The low grade raw materials as available pose a significant opportunity for human race for delivering value. They offer an easier reach to a value as perceived in end use but the journey is full of challenges. The first challenge is development of technology for maximizing grade recovery as required by the downstream process. The second challenge is to make the technology viable so that it contributes value to end use and the third challenge is to keep the net impact of the process positive The mining and mineral processing fraternity, being at the beginning of this value chain is set to take the first step in this journey for a tryst with ultimate human well being. Keywords: sustainable development, challenges in mineral processing

Sep 1, 2012

By K. Yoo

Cuprous oxide is one of the oldest antifouling agents and also acts as red pigment in these paints. In printed circuit board manufacturing industries, waste etchant contains a substantial amount of copper ion. In the present study, a process was suggested for recovering cuprous oxides from the waste etchant and optimum conditions were investigated to recover the cuprous oxides. The process consists of two steps: in first step, Cu powder is added into wastewater solution, and cupric ions re-duce into cuprous ions (Cu+Cu2+?2Cu+), where cuprous ions precipitate as cuprous chloride; In second step, cuprous oxide is synthesized by adding NaOH into cuprous chloride solution (2CuCl+2NaOH?Cu2O+NaCl+H2O). Optimum conditions were investigated to recover cuprous oxide in the processes. When copper powder was added into wastewater with copper ions, Cu concentration decreased from 15.6% to 2.6% and ORP decreased from 620 mV to -59.9 mV. This result shows that cupric ions reduced into cuprous ions. XRD data indicated that the precipitate was cuprous chloride powder. Using the cuprous chloride recovered and NaOH solution, cuprous oxide was synthesized. To investigate the optimum condition, various NaOH solutions were added into water with CuCl, and then pH, ORP, Cu concentration, Cu contents in precipitates were analysed. XRD data showed that main component of precipitates was cuprous oxide.

Jan 1, 2014

By T. C. Rao

This presentation identifies how mineral (coal included) processing profession should look at the challenges (threats) being faced by mineral industry. Presently, the focus is more on supply and demand on minerals. In addition, the R&D activities in the chain of mine-to-metal are paying more attention (if not only on) the processes being adopted, development of new equipments and modeling and simulation. But the profession is grossly ignoring aspects such as impact of the processes on other resources, of the ways we extract, use and dispose them socio-economically and efficiently. A business model which may encompass all these dimensions are essential for the sustainable development of mineral industry and a possible approach in this direction is presented. To start with, for the sustainable growth and existence, the profession must be aware of the prospective impacts of their activities on critical factors such as ? political (changing government policies), geographical (environment, land, water and habitat), which have major bearing on the survival and growth of the industry. Mineral Processing professionals have to join hands with mining engineers to answer some relevant questions related to the impact of mineral industry on society. Mining can become economically viable only if mineral processing engineers come out with innovative solutions to reduce capital and operating costs. The solutions have to be adoptable and practically feasible so that industry looks at us for directions. In fact, we have to move towards beneficiation of nano particles striving towards zero waste. Some of the gaps in the knowledge of procedures being followed in the design and operation of processing plants are highlighted. Enhancing the knowledge base for solving unexplored possibilities, solutions to evolve sustainable development measures which demands innovation both at academic and practicing levels is the need of the future. Well-structured academic programmes are to be formulated so that the graduates of these programmes can make an effort to look at processes/concepts with a new insight and approach; the profession should excite the young brains with challenges. R&D funding agencies have to have a long-term perspective on mineral processing so that closer interactions between academic institutes, industry and R&D organizations are sustainable and that innovations are at least a few years ahead of needs of future challenges. Keywords: sustainable growth

Sep 1, 2012

By Robinson Irarrazabal, Edison Collinao, Rodrigo de Carvalho, Patricio Davila, Marcelo Tavares

"In recent years, DEM (discrete element method) softwares, along with 3D laser measuring equipment, have become powerful tools to describe mill charge behavior, as well as forces acting on the liners of SAG mills. With the aim of contributing to streamline this application of the advanced technologies ME Elecmetal and Universidade Federal do Rio de Janeiro, UFRJ, proposed a new approach to improve the design of mill liners using elements from mechanistic modeling of grinding. The paper presents a methodology for continuous improvement of liner design, which uses information from the DEM collision energy spectra in the mill discriminated for the different components (ore and steel balls), as well as information on the breakage properties of the ore being ground. From these it proposes the concept of "effective collisions", which corresponds to the collisions that are of sufficient magnitude to cause breakage, thus allowing to discriminate from impacts that do not cause breakage either in a first impact or after repeated loading. It also tracks the collision of steel balls against the shell in order to assess their potential damage to the liners. An industrial case study is presented of a 38’ diameter SAG mill, which was experiencing challenges associated to liner breakage and low efficiency with the old liner design. Through a modification of the liner design, simulations demonstrated the potential benefit associated to reduction in ultraprojection and improvement in mill capacity. Implementation of the new design in the SAG mill was carried out, resulting in increase in daily throughput from 6 to 12%. Further, the time spent in liner change was reduced by 47% given the reduction in the numbers of parts. This operation also benefited from having no stops due to unplanned shutdowns to replace broken tiles. These demonstrate the benefit of coupling advanced computational tools to sound engineering principles in continuous improvement of liners."

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 Hans-Åke Häggblad, Bertil I. Pålsson, Jan Stener, Kent Tano, Andreas Berggren, Pär Jonsén

Numerical modelling of grinding in tumbling mills is traditionally done with the discrete element method (DEM). The grinding balls are then represented by DEM particles and the mill structure is considered rigid. To include more physical phenomena several numerical methods can be combined. One important improvement is to include the mill structure response, using the finite element method (FEM). The interaction between charge and lining can then be studied in detail. The pulp can also be included using a particle-based continuum method e.g. smoothed particle method (SPH). The strength of SPH lies in modelling of free surface flows and very large deformations and it is suited to model simultaneous fluid and granular flow. Still, the coarse particles (grinding balls) in the charge are suitable to be model using DEM. Each of these methods has their strength and weaknesses, but combined they can successfully mimic the main features of the charge movement. With these numerical tools the complex interaction between the different components of the grinding process; pulp, charge, lining and the mechanical behaviour of the mill, can be studied together. This work will present novel numerical approaches to model, simulate and validate charge behaviour in tumbling mills. These numerical models give possibilities to better understand the physical and mechanical behaviour of particulate material systems during grinding in a tumbling mill. This is important in order to develop and optimise future high-capacity grinding circuits and save energy.

Jan 1, 2014

By Gabriela Pino, Maurício Torem, Lorgio V. Gonzales

It has been long known that many microorganisms are able to interact with mineral particles to obtain a concentrate; thus, one possible technique is flotation and its related process. Biological process have been attracting attention in mineral processing due to lower operating cost and their possible applications to process low-grade and fine ores. The adhesion of microorganism to surface of mineral particles can alter the hydrophobicity of mineral markedly. Such surface modifications modify its hydrophobicity or hydrophilicity will be used to flotation of cassiterite fines. The major difficult to float fine particles is attributed to the low probability of bubble-particle collision, one characteristic of electroflotation process is the ability to create very tiny bubbles, which is known, improve the collision efficiency and flotation performance of fine particles. In this study, the electroflotation of fine particles using Rhodococcus opacus strain as bioreagent was investigated. Electroflotation experiments were carried out using particles of cassiterite around 8µm of mean diameter the adsorption of R. Opacus onto cassiterite particles was confirmed by Fourier transform infrared spectroscopy (FTIR), electrokinetic and contact angle analyses. The measurement of bubble size by laser diffraction showed a mean bubble size of around 26 µm, current density and bacteria concentration appear to be the main parameters affecting the mean diameter of bubbles, electroflotation tests reported recovery around of 64.5 % at pH 5, concentration of 2,87 x10¹² cells/ml (50 mg/L) and current density of 51,4 mA/cm2.

Jan 1, 2014

The Arctic is a region of special economic, geopolitical, research, socio-ethnic, and defense interests of both Russia and other countries of the Arctic zone. Introduction of innovation technologies at ore-processing factories is a direct responsibility of the state and this problem should be solved on the basis of coordination of interests of different stakeholders. The task of elaboration of scientific principles of rational state regulation in the North is very topical. Innovations require considerable investments first of all from private capital. However as an investment object innovations are not attractive for investors as they require large expenditures for long-term projects, and they are connected to high risks because market incentives form striving to get quick profits of private companies and result in a certain behaviour strategy while innovations need ?long money?. Under such conditions without state regulation of investment and innovation activities development of the mining sector in the Arctic practically has no prospects. At innovation development of mining enterprises economic growth is provided at the expense of active state innovation activities. The elaborated strategy of ore-processing enterprises should correspond to the modern paradigm of the ore-processing industry development which is not only for extraction of minerals but also for multi-profile structure having comprehensive use of the resources on the rational basis intended for rational complex utilization of mineral resources of the AZR which by the definition includes maximally full use of the whole aggregate of resources on the economically rational basis with obligatory environmental with resource reproductive and socio-economic functions and deterrents. The main principle of creation of innovation technologies is to obtain more products of higher quality with minimal costs. This allows increasing ?productivity of the resources? several times. This principle makes increasing productivity of the resources the most important and in this case efficiency of use of the resources brings extra profits at the expense of lack of new costs such as payment for protection and utilization of wastes. According to the economic theory only ratio between demand and supply is able to fix optimal proportions in economy and to give necessary signals for investment activities of mining enterprises. In this context market for minerals and increase of mineral resources productivity do not create incentives for investment activities without which neither sustainable economic growth nor solution of macroeconomic tasks are possible. Nevertheless countries should not reject this idea in spite of economic efficiency of the enterprises. Extraction degree of useful components and especially oil in the Arctic zone is one of the lowest in the world. This can lead to crisis of oil industry and other mining sectors. The reason for that is lack of a state policy of realization of innovation technologies in the mining sector in the Arctic.

Jan 1, 2014

By V. P. Yakushkin, B. S. Ksenofontov

"Multistage model designed and used for more detailed description of floatation process. The study develops a new model of flotation kinetics description. It defines flotation as process that consists of several stages: air bubbles and particles are separate, air bubbles and particles form a raising aggregate, aggregate raises to froth layer. This description significantly differs from commonly used model, which is much simplified. The multistage model gives an in-depth description and considers different aspects of flotation. Experimental approval of the new model resulted in its accuracy.The model is to be used for description of all flotation processes’ kinetics of wastewater treatment. It helps in accurate designing of flotation treatment plants and may be used for further research of flotation process. Columnar flotation installation was designed by using multistage model. This installation consists of new tubular aerators with special ejectors, froth pressing system as well as unit of thin-layering lighting to catch microflotocomplex “particle – bubble”. Usage of tubular aerators allowed to aerate the overall volume of pulp. Due to use of special ejectors with longer mixing camera we state higher volume of small-sized floto-active bubbles. Use of multistage model allowed to optimize and get higher technological results of potash salts enrichment. Tests were conducted on centrifuges-floatation installation system. Meanwhile, froth concentrate contained mainly thin hydrophobic particles sized circa 0,1 mm. As a result we set that during floatation cleaning process of froth concentrate 95-98% of chloride potassium (KCI) is derived from foam.The final product satisfies production quality. Columnar floatation installation productivity was 17 – 21 m3/m2h, which is a high technological result. Columnar floatation installation is one of the best examples of concentrating equipment using nearly all technological indices."

Jan 1, 2018

By Vasile Murariu, William Pate, John Herbst, Dilek Alkac

"Multiphysics models are essentially first principles models capable of providing very accurate micro scale predictions. The computational requirements for Multiphysics Models are extensive, precluding their direct use for flowsheet simulations. Population balance models get their form from theory but the model parameters have to be provided from experiments. The prediction errors for the population balance models are typically significantly higher than those for the Multiphysics Models but the computational effort for Population Balance Models is typically much less than that for the Multiphysics models. The hybrid model described here takes advantage of the strengths of each of the two primary model types and minimizing the weaknesses of each. The Multiphysics Model is used to perform high accuracy "experiments" that are difficult or impossible to conduct in laboratories or plants. The results of these experiments are combined with standard laboratory or plant data to parameterize and further enhance the Population Balance portion of the hybrid model. The creation of a useful Hybrid Model is demonstrated for a MP1000 secondary crusher. The validation of the hybrid crusher model is also presented. Finally the use of the Hybrid Model is illustrated in a full comminution flowsheet simulator."

Jan 1, 2014

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

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

Jan 1, 2018

By Teja Reddy, Narasimha Mangadoddy, Mandakini Padhi

"In mineral comminution circuits, the feed to hydrocyclone consists of a heterogeneous mixture having varied degrees of liberation and sizes leading to the multi-component particle system. The presence of multicomponent particles exhibits a significant change in the classification performance parameters. In this work, a numerical study is conducted with an artificial mixture of magnetite and silica of different proportions having similar particle size distribution to understand the multicomponent interaction in a laboratory scale hydrocyclone. The heterogeneous feed is injected tangentially would attain different settling rates under the influence of centrifugal, drag and turbulent dispersion forces. In this work, Large Eddy Simulation (LES) is used to resolve the continuous phase turbulence. Modified Algebraic Slip Mixture (ASM) model using the corrected Newtonian rheology of fines to simulate multi-density and multi-size particles of the mixture in a hydrocyclone. The influence of the multi-component particles on classification performance is extracted from the simulation in terms of the performance curve, i.e. recovery to underflow, volume fraction distribution and the key forces acting on each particle in the mixture. An interaction was observed between different components during the classification process, featuring accumulation of heavier particle at wall-side pushing the lighter particles into the inner locus of zero vertical velocity (LZVV) zone. The comparison of separation factors of different size particles presented the higher probability of the magnetite of same size reporting to wall region and hence to underflow. Hence, an increased component cut-size with the increased magnetite proportion, particularly a profound effect on lighter density component’s cut-size was observed. INTRODUCTION The multicomponent existence is found in naturally occurring ores, affecting the pure metal extraction, nonetheless also affects the comminution and classification processes. Among many another classifier, hydrocyclone is a vital equipment used vastly in many industries. The main advantages over other classifiers are a static body, low operating cost and maintenance, high throughput, low floor space requirement etc. A typical hydrocyclone consists of a cylindrical section with a central tube connected to a conical section with a discharge tube. The fluid is injected tangentially into hydrocyclone causes swirling and thus generates centrifugal force within the device. The multiphase interaction inside the hydrocyclone is extremely complex and mostly explained by theories based on hypothesis. In past years, many theoretical models were proposed like a balanced orbital model (Criner, 1950), the residence time model (Reitema, 1961) etc. Though these models give an estimation of the cut-size and other performance parameters, it cannot predict the accurate performance of the actual state of operation. Among these models, the balanced orbital theory is the most adapted concept, based on the force balances of the particle in the dual vortex flow of hydrocyclone. The finer particle is subjected to the inward drag force, generated from the outer vortex flow to the air core, and drags the particle towards the overflow. The larger particle with the higher mass have enhanced centrifugal force and falls into primary vortex near wall reporting to the underflow. Generally, the forces acting on the particle include the drag force, centrifugal force, pressure gradient force, added mass force, Saffman lift force, Magnus force and basset force (Kraipech, 2005). The major forces like a drag, centrifugal, pressure gradient are the function of the particle properties like the size and the density. Hence, the existence of the multi-size and the multi-density particle will affect the separation phenomenon, with the varied forces acting on it. The understanding of the multicomponent classification effect using ores has been only explored in few studi"

Jan 1, 2018

By M. Muravyov, T. Kondrat’eva, A. Bulaev

Metallurgical treatments of sulfide ores containing copper and zinc are characterized by significant losses of base metals, particularly formation of the flotation tailings and slags during the dressing and pyrometallurgical treatment respectively. In addition, SO2 gas obtained during roasting and converting may be as raw material for sulfuric acid production. A treatment of the industrial metallurgical wastes has been investigated. Two samples of old pyrite tailings from two concentrators that contained 0.36% and 0.26% of copper and 0.23% and 0.22% of zinc were leached with 10% sulfuric acid in the column. Recovery of copper reached 47% and 38% while recovery of zinc was 47% and 41% from the first and second samples, respectively. The pregnant leach solutions contained 15.9 g/l and 10.5 g/l of ferric iron. Ferric iron is the strong oxidant and ferric containing pregnant leach solutions can be used for ferric leaching of different types of raw materials containing sulfide minerals. Therefore, ferric leaching of copper converter slag flotation tailings contained 0.53% of copper and 2.77% of zinc with the first pregnant leach solution was conducted. The effect of various experimental parameters on the leaching dynamics of copper, zinc, and iron under batch conditions was investigated. Under the best conditions (temperature 70oC, pulp density 30%) the recovery of copper and zinc reached 80% and 42%, respectively. Thus, it has been shown that acid leaching of base metals from old pyrite flotation tailings with using of the pregnant leach solution for the ferric leaching of copper converter slag flotation tailings is a prospective technique for the complex treatment of mining and metallurgical wastes. Investigated processes could be introduced into the technological flow-sheet of typical pyrometallurgical plants.

Jan 1, 2014

By Fang Liu, Xin Tan, Zhong-ming Wang, Yan-bo Shang, Jie Zhao

"The flotation separation of sulphides bulk concentrate containing Cu, Zn, Mo and Bi, which was obtained by both table-flotation of gross sand of gravity separation of wolframite and bulk flotation of wolframite slimes using butyl xanthate and oil No. 2, etc., has been conducted by using the cyanide process in the tungsten concentrator. The process has problems of high reagents consumption (25 tonne of cyanide dosage per year) and mineral processing cost (800~1000 RMB reagents cost per tonne of by-product concentrates), high mutual containing loss in the by-product concentrates and serious environmental pollution caused by lots of cyanide-containing wastewater. In order to solve this problem, a new cyanide-free separation technology is studied, which is used to process this sulphides bulk concentrate with 8.68% Cu, 8.98% Zn, 0.26% Mo, 1.58% Bi and 40.12% S. The results of the closed circuit test show that Cu, Zn, Mo and Bi can effectively be separated from this sulphide minerals concentrate by using the reasonable flotation-gravity flowsheet, high-efficiency collectors and regulators simultaneously. The metallurgical recovery and concentrate grade are as follows: molybdenum recovery is 94.63% with 50.62% Mo content; copper recovery is 85.18% with 29.29% Cu content; zinc recovery is 75.92% with 46.49% Zn content; total Bi recovery is 65.08% with 16.86% Bi content. The new technology is an alternative to the cyanide process due to its low cost for reagents, satisfying separation results and economic profits, and solves the problem of environmental pollution caused by the use of large quantities of cyanide. Some important parameters in separating the Cu-Zn-Mo-Bi sulphides concentrate are also introduced in this paper. This study provides pretty good technical support for separating the polymetallic sulphide ores containing Cu, Zn, Mo and Bi by cyanide-free technique."

Jan 1, 2014

By Zhazira Baltabekova, Nina Lokhova, Arailym Dukembayeva, Madali Naimanbayev, Zhantore Dzhurkanov

"Recycling of industrial waste provided they have enough valuable elements requires significantly less investment compared with ore processing. Promising man-made raw material of rare earth elements (REE) is phosphogypsum. Works performed on dismantlement of phosphogypsum only concern phosphogypsum processing from apatit. In this case, none of the developments was tested for phosphogypsum produced on the basis of phosphorus, chemical and mineralogical composition of which is markedly different from apatites. We studied phosphorites of the Karatau deposits (Kazakhstan). Mineralogically all the layers are composed of three main ingredients: phosphate, silica and carbonate, which account for 92-96% of the weight composition of ores and rocks. Of impurities there are pyrite, iron hydroxides, gypsum, fluorite. In addition to the actual composition of phosphate in phosphate ores there are apatite. Silica is presented by chalcedony and quartz, and carbonate by calcite and dolomite. The results of X-ray microanalysis showed point cluster of grains containing REE in samples of phosphate ore. Analysis of the grain showed that REE are in the form of phosphates and silicates, which according to numerous studies in apatites is not established. In this regard, phosphogypsum, waste of production, is different in composition too. Therefore, transfer of techniques proposed in the methods for extracting REE from phosphogypsum after processing apatite, did not give the stated results and required a new approach to solving this problem. It should be noted that the phosphogypsum produced by processing the Karatau phosphorite contains medium group of REE by 2.6, and heavy group by 7.8 times more than phosphogypsum from processing the Kola apatite. Given the shortage of medium and heavy REE research to develop ways to extract the lanthanides from phosphogypsum after processing phosphate rock is promising. The study contains results of studies on the extraction of REE from phosphogypsum after Karatau phosphorite processing."

Jan 1, 2014