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By B. Z. Wu

The ore dressing of tin-polymetallic lean ores is a difficult problem and the research emphasis in domestic nonferrous metals mining field. Through research and tackle key problem,and in order to supply reference in dealing with the same types ores, this paper expatiates the exploiture and appli-cation of six item new technology and technics in ore dressing of tin-polymetallic lean ores. It include the technics of multi-step compounding disposing tailings, grinding step by step, grinding and processing circularly technology, high thickness without circle flotation technology, dispersedly flotation tin step by step technology, exceed fine lean plumbum stibium zinc flocculation flotation technology, the synthetically recovery of waste water after ore dressing technology.

Jan 1, 2014

By Z. G. Li

The large-scale vibrating screen has been applied widely in coal industry and other industrial areas as a kind of important device. As vibration mechanical device, it works very hardly and works in very bad environment so that the structure of screen is damaged easily. Therefore, it is very important that how to detect the fault of structure as early as possible to make the repair schedule reasonably and economically and to avoid the body hurt and device damage. As a kind of important structure of vibrating screen, the lower crossbeam is the main carrying structure and it is easily damaged, so it is regarded as a researched object in this thesis and it is tested under the load in the laboratory. Based on the test, acoustic emission wave signals can be got-ten by modern acoustic emission testing technique. Then, the ?wavelet packet - energy? from the characteristics of acquiring signals is used as neural network input vector. In the BP network structure design, the design of a hidden layer with variable number of BP network is established. Based on the error by contrast, the best nerve number can be identified in the hidden layer. Through integrated analysis, using Levenberg-Marquard BP study algorithm, network-training errors are relatively small, the acoustic emission signal is used in BP neural network as a pattern of recognition. In Matlab6.5, neural network model identification is created and taking advantage of nonlinearity and the ability of learning and memory of Neural Network, this model is fixed by training structure of network with training samples. The work presented shows that acoustical emission signal processing and research on early fatigue fault diagnosis based on the wavelet and the neural network is viable.

Jan 1, 2014

By C. Y. Wang

Based on Slurry Electrolysis, and combined with the problems of extraction antimony, lead and their separation from complicated antimony-lead concentrate, a series of tests have been done in this paper. Using Slurry Electrolysis to treat complicated antimony-lead concentrate, antimony and lead can be separated in one step. And 2# metal antimony can be achieved in cathode directly at the same time. Lead in concentrate is restrained still in the residue at the form of PbCl2. After converting the residue with ammonium carbonate and removing sulfur with kerosene, the high quality of lead concentrate (Pb is above 45%, S is below 15%) and pure sulfur can be achieved, respectively. The recovery of all in Slurry Electrolysis process is as: Sb 95%, Pb 95%, Ag 80%, S 60%.

Jan 1, 2014

By T. Onnela

Metso Mining and Construction Technology is one of the world leading suppliers of equipment and knowhow for aggregate and mining industry. The processing capacity, ease of use, and reliability are featuring Metso?s state-of-the-art cone crushers. Crushing is a complicated process affected by numerous parameters. The optimized crusher kinematics is one of the key factors for high performance. To fine tune the crusher kinematics and crushing chambers one needs to know how different parameters affect. The main cone crusher parameters are head angle and diameter, gyration point, shaft speed, eccentricity, stroke length, and inclination and design of crushing cavity. Selecting the correct combination of these parameters is a multi task optimization challenge. In practical life there are more factors to achieve satisfactory performance, like crushing chamber wear and profile management keeping the performance constant over the whole wear life, control of crusher frame loads, ability to handle disturbances in feed material etc. The extensive research work has lead to a solution that enables the highest possible material density in the crushing chamber. This design provides maximum reduction of processed material and thus increased share of 0/10 mm product. High density in the cavity offers further benefits, such as high throughput capacity, less material contact with wear parts and even load on crusher frame and bearings. The challenge that an equipment supplier involved with high density crushing is how to design a robust cone crusher, which is able to cope with the high crushing forces due to high resistance from the crushed material against the gyration movement. Metso has launched a new series of cone crushers HP3, HP4 and HP5 that are all able to work in high density crushing applications The test results and evidence from over 300 installations clearly prove the effectiveness and importance of high density crushing. Keywords: cone crusher, crushing chamber, crusher kinematics

Sep 1, 2012

By G. X. Du

Reaction kinetics of serpentine and hydrochloric acid is theoretical basis for optimizing reaction process conditions of serpentine and hydrochloric acid. Kinetics of serpentine and hydrochloric acid was studied in this paper. The results indicated that apparent reaction order to hydrochloric acid was two and reaction kinetic equation could be expressed as: 2HClHCl,ddtckct-=·. The diffusion rates of hydrogen ions in liquid film on surface of serpentine particle and in amorphous silica layer generated in the reaction and chemical reaction velocity during the reaction had important effects on to-tal reaction velocity. And chemical reaction velocity had the most significant influence. The relation of conversion rate of magnesia xMgO with reaction time could be expressed as: 1(1)xkt--=·.

Jan 1, 2014

By Sami Makni, Ahmed Bouajila

"To remain competitive in an open market, mining companies are more and more requested to optimise their complex and highly multivariate processes. The increasing amount of process data, brought about by intensive use of instrumentation and the progress in computer data acquisition, enhances the need for more and more powerful and robust tools for the analysis and modelling of the process data. Now, with the emergence of multivariate data analysis (MDA) techniques, on-line clustering of mineral process behaviour is possible and could help in the extraction of valuable process operation indicators. MDA can be used in different mineral processes such as flotation, grinding, smelting etc.In this paper, we focus on grinding process considered as the most costly and power consuming node of the mineral processing scheme. Different objective-oriented levels of data clustering will be addressed.First, the evaluation of grinding operation taking into account data and constraints from all processes before (e.g. blasting, crushing) and after (e.g. flotation, leaching, etc.) the grinding node. The second level deals with process diagnosis by differentiating operation level and identifying behaviour drifts. Control and optimisation are two other levels concerned here with the selection of optimum trajectories in the drift correct.Industrial plant data are processed in order to illustrate the feasibility and the potentiality of MDA applications in addressing the clustering and interpretation of grinding mill behaviour."

Jan 1, 2003

By Yongfu Yu, Xiaotie Wang, Fuguang Zhang, Liping Che

"The flotation process of native Rare Earth minerals such as bastnasite, monazite, mixed minerals of bastnasite and monazite, using the new effective collector Dh was studied in this paper, respectively, and the flotation properties are described. The good qualities of the new collector Dh were revealed through comparing with other collector of Rare Earth minerals. The test results of different ore samples show that at moderate pulp pH (8.5-9.5), Rare earth minerals can be effectively separated from barium, calcium and silicon bearing intergrowth minerals (barite, calcite and silicate minerals) and high quality Rare Earth concentrates can be obtained successfully by the new collector Dh, acid silica gel, turpentine and reagents fitting together rationally. In order to determine optimum technical conditions, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents (Dh and acid silica gel) on the flotation were investigated in the test.Simultaneously, the paper explores the mechanism of the flotation of Rare Earth minerals from intergrowth minerals. The infrared spectra for Dh and Rare Earth cation by analysis in theory shows that Dh formed chelate complex with Rare Earth cation and were adsorbed on the surfaces of Rare Earth minerals. The mechanism of the intergrowth minerals depressed by acid silica gel can be explained as gummy colloid hydrolyzed from acid silica gel which are selectively absorbed on the gangue minerals, making them hydrophilic and depressed, with pulp pH value of alkalescent."

Jan 1, 2003

By Y. S. Sun, P. Gao, Y. F. Li, J. W. Yu

"Oolitic hematite ore is one of the most refractory iron ores in the world. It is not feasible to separate iron minerals from raw ore by conventional mineral processing methods. In recent years, a new technology called coal-based reduction followed by magnetic separation has been employed to produce metallic iron powder from oolitic hematite ore effectively. In order to find the nucleation mechanism, a thermodynamic analysis of the carbothermic reduction of oolitic hematite ore was conducted by the HSC 6.0 thermochemical software. The phase transition and microstructure changes during the coal-based reduction were also investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the iron oxides in the oolitic ore were reduced to metallic iron following the route of Fe2O3–Fe3O4–FeO–Fe in reduction process. The reduction reactions preferentially occur in the high activity regions to form a higher concentration of Fe elements, and then more supersaturated Fe separated out to form new phase nuclei. Under the action of homo-aggregation and principle of minimum free energy, the iron cores continuously absorbed migratory Fe around and grew into quasi-spherical iron particles embedded in slag phase. INTRODUCTION With the rapid increase of steel industry, premium grade iron ore in China has been gradually exhausted, and its supply has become bottleneck for the development of iron and steel industry (Guo et al., 2015). Therefore, it is urgent to exploit the refractory iron ores, such as oolitic hematite ore. Oolitic hematite ore is widely distributes in France, Germany, America, Canada, Pakistan, China, and among other countries (Maynard and Van Houten, 2004; Li et al., 2011). In China, the explored reserve of oolitic hematite ore is 3.72 billion tons, which accounts for approximately 1/9 of total iron ore resources of China (Gao et al, 2016). Oolitic hematite ore possesses complex composition,"

Jan 1, 2018

By E. A. Brocchi

This work is dedicated to the chemical treatment of a typical EAF dust by chlorine content agents. The residue contains 48% Fe2O3 and 28% ZnO mainly in the franklinite structural form. The others less compounds are: 4.00% CaO, 2.60% MnO, 2.20% MgO, 1.08% PbO, 0.36% Cr2O3, 0.21% B2O3, 0.03% CdO and 0.01% NiO. The experiments purpose is selectively to remove zinc from the residue leaving the iron behind. Thermodynamics studies have indicated some roasting possibilities. The experimental results have shown that both HCl leaching and carbochlorination will remove iron and zinc without any selectivity. However, either the chlorine or the calcium chloride roasting seems to form, preferentially, the zinc chloride. So, it will be presented how the EAF Dust can be treated by the using of chlorine roastings process such as carbochlorination in order to separate the zinc and iron present in the frankilinite, main EAF dust content.

Jan 1, 2014

By Tilak Raj Mankhand, Mudila Dhanunjaya Rao, Kamalesh K. Singh

"Zinc dust is used for the removal of primary impurities by cementation from the zinc sulphate electrolyte before electrowinning of zinc. However, the industrial zinc electrowinning plants has been reported that the zinc dust consumption is in large excess than the stoichiometric requirement. In the present investigation, morphology of the zinc dust has been altered by ball milling and utilized for the cementation of cadmium, which is one of the major impurity and compared the change in the rate of cementation with original zinc dust. Initially, 325 mesh size zinc dust was used for the optimization of the excess quantity of zinc dust to be used at a temperature of 50 °C. The chemical analysis of zinc dust before and after ball milling and morphology were studied by scanning electron microscopy (SEM), and the solution was characterized by Atomic Absorption Spectrophotometer. The rate of cementation increased with increase in ball milling time. The residual precipitate obtained after filtration was also characterized by X-ray diffraction analysis. Finally experiments were conducted to study the effect of temperature and kinetics of cadmium cementation using first order reaction kinetics. Based on the integral method, the calculated activation energy for the cadmium cementation with 4-hours ball milled zinc dust was found to be 3.39 KJ/mole. INTRODUCTION Primary production of zinc in the world is carried out by hydrometallurgical route. The primary impurities in the neutralized zinc sulphate solution that cause negative effect on electrowinning are copper, cadmium, cobalt, and nickel. Copper diminishes the current efficiency and cadmium contaminates the cathode zinc (Morgan, 1977) while electro winning. Nickel and cobalt lead to perforation in the zinc deposit and prevents the electro winning process (Abrasheva et al, 1984). Due to higher electro positivity of these metal impurities than zinc, they can co-deposit with cathode zinc at the time of electrolysis. In addition to that, some possible impurities (including cobalt) in the electrolysis may lower the hydrogen overvoltage, allowing deposition of hydrogen at cathode resulting in fall of current efficiency. The deposition of zinc on the cathode is possible only at higher hydrogen overvoltage which is practicable in the absence of such impurities (Raghavan et al., 1999). Cementation is one of the prominent purification technique, and in that less reactive metal can be replaced by highly reactive metal by allowing them into precipitation. Cementation of cadmium from zinc sulphate electrolyte is being done by the addition of zinc dust."

Jan 1, 2018

By S. M. Saghaeian

The studies on the product finer than 12 mm due to crushing and sizing plant of Gol-e-Gohar Iron Ore mine showed which this material contains significant amount of valuable iron minerals. Based on the carried out experimental studies on representative samples of fine hematite iron ore, a processing flow sheet was designed to upgrade iron content. This plant is known as first hematite iron ore enrichment plant in Iran which the dry medium intensity magnetic separators (with magnetic field intensity 4500 gauss and high gradient) has been used. The main objective of the plant is production of high iron product with iron content more than 61% and weight recovery more than 55% from the feed with iron content of 54%. In this plant, at first material are screened by a single deck screen (6mm), then oversize particles is separated at one stage by magnetic separator, while undersize ones at two stages. Based on the results of experimental tests, a final high iron product with iron content of 62.4% and weight recovery 63.9% can be achieved. It should mention which the iron content can be enhanced through increasing the speed of magnetic separators especially at the part of separation of finer iron ore.

Jan 1, 2014

By Yuexin Han

The wet preconcentration of haematite, comminuted by high-pressure grinding roller was studied, using the cylindrical ferromagnetic medium. The effects of various factors including rod diameter, rod gap and background magnetic field intensity (BMFI) on the performances of preconcentration for different size fractions and the force analysis of single mineral particles with different diameter in the separation zone were emphatically investigated. The results showed that as the rod diameter increased, the rod gap decreased, and the BMFI increased the tailings grade and the tailings yield reduced while the concentrates recovery raised that was regardless of variations in feed size distribution. For the -3.2+0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 7 mm at BMFI of 454kA/m is used to get a higher performance. For -0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 4 mm at BMFI of 263kA/m is used to get a higher performance. After the classifying preconcentration, at the optimum condition, the overall concentrate grade increases by 9.56 percentage points and the concentrate recovery is up to the 82.67% with a tailing grade of 10.68% and a tailing yield of 40.31%. The magnetic force, exerted on weekly magnetic minerals was proportional, to the specific susceptibility and square of BMFI. For the same BMFI, the magnetic capturing force on coarse particles increased, and that on fine particles decreased with the increasing of rod diameter. For the lean locked-particles, considering the gravity and viscous resistance of particles, rods with a big diameter were beneficial to the capture of coarse particles and had no influence on the capture of fine particles, while rods with a small diameter were good for the capture of fine particles and not suitable for the capture of coarse particles of lean locked-particles. Keywords: low grade haematite, high-pressure grinding roller, high intensity magnetic separation, pre-concentration

Sep 1, 2012

By Mohsen Hashemzadehfini

Nowadays heap leaching has become established as a mineral processing technology for treatment of some low grade minerals such as copper, gold, and zinc, etc. Heap height, particle size, leach reagent consumption, and metal recovery are four important metallurgical parameters in a hydrometallurgical process like heap leaching. This paper investigated the effects of heap height and particle size on copper recovery as well as acid consumption. Three heap heights of 2, 4 and 6 meters and two particle size fractions of less than 25.4 mm and 50.8 mm were selected as variables in the experiments. The research results showed the inverse relation between heap height and copper recovery as well as acid consumption. Under given conditions, the copper recoveries of minus 25.4 mm ore are 78.63%, 66.27% and 52.88% higher than that of minus 50.8 mm samples for the heap heights of 2, 4, and 6 m, respectively. Both copper recovery and acid consumption increase with decreasing particle size. Keywords: heap leaching, heap height, particle size, acid consumption

Sep 1, 2012

By Matti Kongas, Kari Saloheimo, Antti Remes

"The paper studies the control performance of the flotation process as a function of the measurement accuracy and sampling frequency of an on-stream XRF analyzer, using a simple dynamic model. An additional aim is to assess how the economical result of a mineral flotation process depends on the quality of process control based on the on-line elemental assays.An on-stream XRF analyzer measures the concentrations of slurry lines in a continuous cycle from several process points. The control performance depends on the analytical accuracy and sampling frequency of the concentration measurement. With a long cycle time, the state of the process changes before a new measurement becomes available. With short measurement times the statistical variance of the counted X-ray pulses increases, increasing the random error in the analysis. In addition, the measurement accuracy depends on the concentration of the component to be measured from the slurry.To quantify the effect of analysis error and frequency to process control, a simple dynamic process model is created in the Matlab environment. Data from a copper flotation circuit is used as a test case. The process model comprises a first order reaction equation and the grade-recovery -relationship estimated from process data. The control was modeled using the control strategies implemented into a rule based advanced control system.The economical performance of the control was studied by calculating the overall net smelter return at various analyzer parameter combinations. The economical performance of the process declines strongly when the sampling cycle is increased. In studied case the sample measurement time did not have a significant effect on the results. The economical performance of the simulated process corresponds to an almost uncontrolled process when sampling cycles longer than 40 min are applied."

Jan 1, 2003

By S. N. Shahcheraghi

Grinding is one of the most important and expensive steps in mineral processing allocating about 70% of the total energy in the plants. Nowadays, for optimizing the energy consumption in these equipments, the rock behavior and its size distribution during the crushing have been normally predicted using selection and breakage functions to be able to optimally model and design grinding circuits. For this purpose, the case of Miduk copper mine in Kerman province, Iran was studied. The samples were taken from primary ball mills feed and were subject to screen analysis to achieve uniform sizes. Then, selection and breakage functions were determined at the different grinding times in laboratorial ball mill. Finally, ore size distribution in different grinding times was estimated using MATLAB software

Sep 1, 2012

By Xiaodong Jia, Williams. Richard A.

This paper describes the recent developments, arising from research at Leeds, in the computer modelling of packing of complex shaped particles and prediction of physical properties of the structures represented by the packing. The computer model DigiPac, is capable of packing particles of any shapes and sizes in a container of arbitrary geometry. The ability to predict packing structure of real particle shapes and to compute directly some structure-dependent physical properties (such as liquid permeability, mechanical strength/ stability, compaction and sintering, dissolution and leaching, etc.) is obviously highly desirable and has significant potential in industrial applications. Examples are presented relating to the packing of granular materials.

Jan 1, 2003

By S. Z. Khan, Veerendra Singh, Y. Rama Murthy, S. Prasad, Sunil Kumar Tripathy, Gajanan Kapure

"In this study, a low-grade ferruginous low-grade chromite ore was subjected to reduction roasting by using conventional heating as well as microwave heating. Sukinda chromite ore deposit contains majorly iron-bearing minerals as gangue phase. The magnetic susceptibility of these minerals enhances effectively after reduction roasting. Alteration of crystalline structure and magnetic property of these metals enables separation of low-grade ore by using magnetic separation. Conventional roasting studies by varying the temperature, time of reduction and reductant dosage were changed for low-grade ferruginous chromite ore. Similarly, microwave power, retention/exposure time and reductant dosage varied for reduction roasting studies under microwave environment. It is found that low-grade ferruginous chromite ore can be upgraded by reduction roasting and 61.2% Cr2O3 was recovered with a chromium-to-iron ratio of 1.93 from feed chromium-to-iron ratio of 1. Microwave reduction roasting studies resulted in upgradation of chromium-to-iron ratio to 1.73 with a recovery of 21% Cr2O3.INTRODUCTION The chromite ore occurs as a spinel containing oxides of chromium, iron, magnesium and aluminium. Most of the Indian chromite deposits are of ferruginous (rich in iron content) which indicates the abundance of ferruginous gangue minerals along with chromite. The primary use of chromite ore is towards the production of ferrochrome alloys. Chromite ores with less than 40% Cr2O3 and the chromium-to-iron ratio (Cr-to-Fe ratio) <1.8 is considered to be unsuitable for the smelting process (Tripathy et al. 2012, Tripathy et al. 2012a). A considerable amount of low-grade chromite ore and overburden excavated during chromite mining is getting accumulated every year, causing a threat to the environment. Its disposal poses a significant challenge and, hence, the beneficiation of low-grade chromite ore and its utilisation has been attracting a lot of attention. Different physical method of beneficiation methods is generally employed for the improvement of the Cr-to-Fe ratio (Tripathy et al. 2012, Murthy et al. 2011, Tripathy et al. 2012a, Tripathy et al. 2013, Tripathy et al. 2016, Tripathy et al. 2017, Tripathy et al. 2017a). It is observed that the enrichment of the chromite ore is carried out by using gravity and in some places by magnetic separation. However, the enrichment of Cr-to-Fe ratio from low-grade ferruginous chromite ore is difficult by using the above-mentioned beneficiation methods due to the presence of near gravity and near-magnetic susceptibility minerals along with chromite. However, an alternative beneficiation method is needed to explore for the beneficiation of such mineral deposits. Reduction roasting followed by magnetic separation is an alternative option for the separation of these types of ores which is widely reported for the iron and manganese ore (Li, et al., 2010; Chun, et al., 2014, Rath et al., 2018). These processes are majorly focussed on differentiating the magnetic susceptibility between minerals and subsequent separation by using magnetic field. The main advantage of such method is dry process option along with the pre-processed product for the costly smelting process. Also, the roasting of minerals in a microwave environment is also an active research topic in the recent time. So, the amenability of the separation feature of the roasting process by using conventional heating as well as microwave heating can be can be studied for the low grade ferruginous chromite ores."

Jan 1, 2018

By Ashish Agarwal

For a correct evaluation of the performance of any process, it is important to reconcile the data gathered in the plant from the material balance point of view for all the streams flowing in and flowing out of the process unit. There are two main approaches to reconciliation of data, which involve minimization of the sum of the squares of: (i) the closure residuals and (ii) the component adjustments; both weighed with the estimated variances of the components. Though, these approaches have served us well, it has not been possible to ascertain if the reconciled values for various components and the split factors obtained using these approaches are truly the best estimates. In this paper, this aspect has been investigated by analyzing pseudo-experimental data of known error structure on size classification of particles in a hydrocyclone. Three types of basic error structures were considered for the measured component values: absolute error, relative error and chi-square error. The error structure was modified by adding a random component of error using normally distributed random numbers corresponding to zero mean and different levels of variance. By carrying out a large number of simulation experiments, it has been shown that in the presence of random errors, irrespective of the basic error structure of data, which is usually unknown, the chi-square error minimization criterion can be used to obtain most reliable results. Keywords: data reconciliation methods, chi-square error minimization

Sep 1, 2012

Certainly, one of the core processes for the recovery of fine magnetic susceptible iron ore particles, mainly hematite iron ores, is the wet high intensity magnetic separation or WHIMS. This paper outlines a variety of recent developments and innovative process designs in the JONES® type WHIMS. It highlights the latest examples of flow sheets in terms of the diversity of combined rougher, scavenger, cleaner stages and adds to this the new more advanced JONES® type WHIMS equipment technologies like the HIGH FLOW ? HF, the QUATTRO ? Q and the SPLITT OPERATION ? SP. As a result of the increase of the capacity and magnetic intensity, the specific production cost could be decreased. The high worldwide acceptance for this continuous development testifies for the success and state of the art technology.

Sep 1, 2012

By L. Y. Feng

The percentage of leached zinc in massive zinc oxide ores (11.7% Zn, >2 mm) is up to 73.3 % in 120 days. Alternatively, crushed to -0.154 mm, mixed with cement 5% (wt), pelletized and solidified. The diameters of the pellets obtained are between 5 mm to 8 mm. When the pellet solidification periods are 3 days, 10 days and 45 days respectively, the alkaline leaching rates of zinc in the pellets are up to 95.8%, 89.1% and 76.4% respectively. Decreasing the solidification time can re-duce reaction time, increase dissolution of zinc in pellets and lower the effect of initial zinc concentration on leaching rate. The experiment results show that the minimum solidification time is three days, and the kinetic study indicates that alkaline leaching of the low grade zinc oxide pellets is controlled by the diffusion of the leach liquor through the gangue layer in the whole leach process, and the apparent rate constants are 3.33×10-2 day-1, 9.18×10-3 day-1, 5.82×10-3 day-1 respectively.

Jan 1, 2014