Mineral Processing Plants Research Articles

Mineral processing plant site selection using integrated fuzzy cognitive map and fuzzy analytical hierarchy process approach: A case study of gilsonite mines in Iran

Selecting the most suitable location for a mineral processing plant is of vital importance for achieving the highest throughput and lowering overall costs. The aim of the research is to select the best location for a gilsonite processing plant (Kermanshah Province, Iran). First, laboratory scale concentration experiments were conducted to determine the most suitable concentration technique for the material from all gilsonite mines nearby. It was concluded that, one production line is enough to concentrate of the material from all mines by flotation method. Afterwards, the effective criteria for locating the processing plant were identified as processing, facilities and infrastructure, mining, environmental, geographical, social and cultural, legal, geological and finally technical and technological factors. Considering the multiplicity of effective factors and interactions between them, fuzzy cognitive map (FCM) method is used for ranking of the factors. A survey for the evaluation of each factor was conducted through interviewing a number of experts in various mining engineering fields. Then, the FCM method was used to determine the weights of each factor. The results show that distribution of mines is the most important factor. In order to determine the appropriate site for installation of the plant, 4 sites were selected in the vicinity of larger mines by investigating the geological maps, using Geological Information System (GIS), aerial photos and objective visits. In order to obtain the global weights of alternatives, the local weights obtained from FCM and FAHP methods were combined. According to the results, site No.4, located at longitude 34˚ 18′28″ and latitude 45˚ 41′ 49″ was proposed as the best location.

Dimensioning a stockpile operation using principal component analysis

Mineral processing plants generally have narrow tolerances for the grades of their input raw materials, so stockpiles are often maintained to reduce material variance and ensure consistency. However, designing stockpiles has often proven difficult when the input material consists of multiple sub-materials that have different levels of variances in their grades. In this paper, we address this issue by applying principal component analysis (PCA) to reduce the dimensions of the input data. The study was conducted in three steps. First, we applied PCA to the input data to transform them into a lower-dimension space while retaining 80% of the original variance. Next, we simulated a stockpile operation with various geometric stockpile configurations using a stockpile simulator in MATLAB. We used the variance reduction ratio as the primary criterion for evaluating the efficiency of the stockpiles. Finally, we used multiple regression to identify the relationships between stockpile efficiency and various design parameters and analyzed the regression results based on the original input variables and principal components. The results showed that PCA is indeed useful in solving a stockpile design problem that involves multiple correlated input-material grades.

Nonzero-Sum Game Reinforcement Learning for Performance Optimization in Large-Scale Industrial Processes.

This article presents a novel technique to achieve plant-wide performance optimization for large-scale unknown industrial processes by integrating the reinforcement learning method with the multiagent game theory. A main advantage of this technique is that plant-wide optimal performance is achieved by a distributed approach where multiple agents solve simplified local nonzero-sum optimization problems so that a global Nash equilibrium is reached. To this end, first, the plant-wide performance optimization problem is reformulated by decomposition into local optimization subproblems for each production index in a multiagent framework. Then, the nonzero-sum graphical game theory is utilized to compute the operational indices for each unit process with the purpose of reaching the global Nash equilibrium, resulting in production indices following their prescribed target values. The stability and the global Nash equilibrium of this multiagent graphical game solution are rigorously proved. The reinforcement learning methods are then developed for each agent to solve the nonzero-sum graphical game problem using data measurements available in the system in real time. The plant dynamics do not have to be known. Finally, the emulation results are given to show the effectiveness of the proposed automated decision algorithm by using measured data from a large mineral processing plant in Gansu Province, China.

Development of automated control system for the mineral processing plant in the process of modernization

The experience of retrofitting the automated process-control system at the mineral processing plant in the conditions of reconstruction of the mineral processing plant LLC JV “Barzasskoye Tovarishchestvo” (Beryozovskiy) is considered. The automated process-control system (APCS), retrofitting goals and ways to achieve them are indicated, the main subsystems of the integrated APCS are presented, and the enlarged functional and technical structure of the upgraded system is presented.

Shifting the boiler units of mining enterprises and processing plants to a new scheme of heat supply

This article analyzes the current situation in the heating circuit of the boiler room. Nowadays the Taiginsky enterprise proposes to modernize the heat supply system. For the first time, the dual circuit scheme is applied instead of a three circuit scheme. The scheme was developed instead of the existing boiler room scheme. There is also a description of the main equipment of the boiler. A hydraulic calculation was performed and a piezometric graph of the existing and proposed schemes was built. In addition, there is the heat calculation of fire-tube boiler and calculated technological losses during the transfer of heat energy to consumers. The calculation of the main technical and economic indicators is given in the economic part. The protection system of boiler units from mechanical and chemical influences is considered.

Correntropy based data reconciliation and gross error detection for bilinear systems

Data reconciliation and gross error detection plays an important role in the process control as measured signals are often contaminated by measurement errors. The simultaneous reconciliation of flow rate and composition measurements results in nonlinear constraints. A Correntropy based data reconciliation and gross error detection method is proposed for the type of bilinear systems with specific to the flow rate and measurement composition. Correntropy is a robust estimator and is effective in reducing the effect of gross errors. Moreover, unmeasured variables can be effectively identified. The Correntropy based data reconciliation and gross error detection method is applied to the mineral processing plant and air separation process for application. Results demonstrate that the proposed method can overcome the weakness of being sensitive to the effect of gross errors.

Copper recovery from thickener overflow by electrocoagulation/flotation: optimization of response surface, modeling, and sludge study

The electrocoagulation/flotation process is a novel approach in mining industry that is implemented to return Cu metal to the production cycle, which improves copper recovery and reduces waste water. In this research work, the response surface methodology was applied to optimize the factors effective in Cu metal recovery and sludge volume produced from thickener overflow. To this end, the D-optimal experimental design was utilized. The influences of four independent parameters including the electrolysis time, initial pH, current density, and electrodes type were studied to investigate the initial Cu grade percentage (28%) and sludge volume produced from thickener overflow. All these parameters were found to have important effects on the Cu metal recovery and the sludge volume produced. The linear and quadratic models were utilized for the Cu grade and sludge volume, respectively. The importance of the independent variables and the interaction between them was assessed by ANOVA. The optimum operating conditions with 27.22% Cu grade were taken to be: electrolysis time: 6.5 min, initial pH: 6.7, current density: 50.2 A/m2, and electrode type: Fe-Al. Similarly, for the produced sludge volume of 861 cm3, the following conditions were found: electrolysis time: 15 min, initial pH: 4.1, current density: 48.7, and electrode type: Fe-Al. The outcomes underscored a practical viewpoint of electrocoagulation, known as an acceptable method for Cu recovery from mine industrials, especially in mineral processing plants.

Assessment of efficiency in reduction of dust concentration in mineral processing plants using the state-of-the-art technical measures

Abstract Airborne coal dust hazard at the workplaces in hard coal processing plants in Poland is presented. The methods for dust control in coal processing plants are discussed. The results from testing the dust control efficiency at the workplaces are given. The test results of airborne dust concentration are analysed as well as advantages and disadvantages of used technical measures are indicated.

Experimental analysis of jet slurry erosion on martensitic stainless steel

Due to their enhanced tribological properties that contribute to an increased useful life of components, martensitic stainless steels are an excellent option for industrial applications such as hydroelectric, petrochemical, civil construction and mineral processing plants. In the present investigation, the erosive wear of AISI 410 martensitic stainless steel is evaluated after thermal treatment by quenching and tempering by mass loss, under erosive attack at 30° and 90° incidence angles, using a self-made jet slurry erosion equipment controlling parameters such as speed, volume of fluid, temperature and concentration of erosive particles of erodent. The characterization of the eroded samples was carried out in terms of the microstructure (SEM) and microhardness as well as the particle size distribution (LG) and morphology of the erodent. It was possible to establish the relationship between the slurry erosive wear and the physical properties inherent of stainless steel for this particular experimental configuration, concluding that the steel presents better resistance to jet slurry erosion wear when compared to austenitic steel commonly used in the industry.

Kibali Gold Mine sulphide concentrate treatment – understanding the preoxidation of sulphide concentrates

ABSTRACTKibali Gold Mine (KGM) processing plant treats both free milling and partially refractory ores. The flotation concentrate, is subjected to ultrafine grinding in 8 parallel FLS VXP 2500 ultrafine grinding (UFG) mills and undergoes a two stage preoxidation process at controlled pH of 10.2, prior to cyanidation. The primary objective of preoxidation is to reduce the reactivity of sulphide surfaces and thus reduce cyanide and oxygen demand downstream. Complex interactions amongst operational parameters of feed density, pH and dissolved oxygen concentration, complicates the circuit.This work demonstrates the impact of these interactions on gold dissolution and cyanide consumption. Aggressive preoxidation conditions have shown that the sulphide oxidation reactions not only increase temperatures but also generate cyanicides consistent with observed high cyanide consumption and poor dissolved oxygen concentration.From the extensive analysis of plant data and laboratory testwork, the plant has established and defined a niche operating domain for optimal preoxidation processes. This has been shown by the resultant drop in the sulphide concentrate residues from above 5 g/t at commissioning to below 3 g/t, currently achieved.

Developing a stepwise approach to simulate a hammer mill through the Whiten model - the adherence for a gold ore

Abstract Comminution represents a large portion of the capital and operating cost of a mineral processing plant. In 1983, Cohen estimated that comminution processes could account for 30% to 50% of the power consumption of the mill, and typically represents 50% of the operating costs of a mine. Therefore, its optimization is directly related to reduction of these operating costs. Among the crushing equipment, the hammer mill is one which is dedicated to operations that aim for a high reduction ratio with the controlled generation of fines. This crusher is recommended for friable and low abrasive ores presenting a high productive capacity. This study aims to develop a stepwise approach that allows the use of the classical crusher model (Whiten-Andersen) in modeling and simulation of circuits containing a hammer mill, simulating the resulting product according to variation of rotation speed within the equipment. The existing model for crushers developed by Whiten-Andersen considers the Perfect Mixing Model, which represents crushing through equations related to selection and breakage functions, that provide an equilibrium condition. This study aims to develop a stepwise approach that allows the use of the classical crusher model in modeling and simulation of circuits containing a hammer mill, by simulating the effect that the variation of rotation speed within the equipment implies in the generated product. The comparisons between the experimental and simulated data indicated that the model fits the data for both, P80 values and percentage passing in 19.1 mm sieve. The model created was validated based on specific experimental campaign.

Improving flocculation and dewatering performance of iron tailings thickeners

Most of the mineral processing and hydrometallurgical plants consume large volumes of water. A portion of this water is recycled to the process while the remainder is lost. This necessitates optimization of dewatering systems particularly in arid and semi-arid mining regions. In this paper the bench and full-scale flocculation behavior of iron ore tailings is investigated in order to improve the dewatering performance of tailings thickeners of an iron beneficiation plant. In the batch settling tests, the effect of flocculant dosage (5–20 g/t solid), slurry solids concentration (3–12 %), pH (4–12), and flocculant dilution (0.05–1 %) on the flocculation performance (settling rate, supernatant turbidity, and sediment volume) was studied. The results reveal that the flocculation performance improves at higher slurry pH and flocculate dosage as well as lower slurry solids content. In the plant-site experiments, the influence of increasing the slurry pH (from 8.1–11.2) and dosage of flocculant (from 8 to 13 g/t solid) together with flocculant injection strategy on the thickening performance was examined. The thickeners underflow density and overflow clarity increased with raising the slurry pH and flocculant dosage as well as distributing the flocculant solution at different locations along the feed stream. The proposed modifications were accompanied by a reduction of 23% in the total water consumption corresponding to an annual savings of $576,000.

Pre-concentration potential evaluation for a silicate zinc ore by density and sensor-based sorting methods

Abstract Pre-concentration consists of the preliminary discarding of a fraction of the mineral processing plant feed which contains little or none of the mineral of interest, reducing the mass to be processed in downstream operations (e.g. milling, concentration and dewatering), as well as the capital and operational costs. In this context, this study investigates the performance of density and sensor-based sorting separation methods in the removal of carbonate gangue of a zinc ore, in size fractions typical of crusher products, using sink and float tests with heavy liquids, jig stratification and laboratory scale ore sorting tests using an X-Ray Transmission (XRT) sensor. The best results were obtained through sink and float in heavy liquids, which indicated the possibility of discarding 30% of the feed mass, removing over 60% of the carbonates (CaO and MgO) and losing only 2% of the zinc. The ore sorting tests also presented positive results, with approximately 93% of metallurgical recovery in 70% of the mass for both size fractions tested. The jig stratification results were worse, since the zinc content discarded with this method was high. The results indicate significant reduction potential for Capex and Opex costs using pre-concentration strategy.

A geometallurgical study of flotation performance in supergene and hypogene zones of Sungun copper deposit

ABSTRACT The feed of mineral processing plants, usually consist of different minerals from various geological zones, which show different behavior in separation processes. In this research, samples from supergene and hypogene zones were provided to investigate the flotation behavior of copper minerals. Flotation experiments were carried out in three phases of supergene sample, hypogene sample and mixed samples. Based on the results, the recovery rate of the mixed sample was 83.61%, which is 7.63% and 1.79% higher than the recovery of the samples of hypogene and supergene zones, respectively. The concentrate grade values obtained for blended, hypogene zone and supergene zone are 10.32%, 2.81% and 12.37%, respectively. The maximum values of flotation constant and infinite recovery are 0.956 (s−1) and 88.833% for the mixed sample. It was also concluded that the highest amount of k and infinitive recovery were related to supergene zone sulfide flotation which are 0.831 (s−1) and 84.33% respectively.

Effects of Cations/Anions in Recycled Tailing Water on Cationic Reverse Flotation of Iron Oxides

It is well known that reverse flotation performance of iron oxides is affected by water quality. Since many potential variations among water sources recycling in a mineral processing plant bring unpredictable effects on the flotation system of iron oxides: disturbing ions/compounds, pH, hardness, residual reagents, etc. In this study, the recycled tailing water from a local plant, characteristically constituting of Ca2+, Mg2+, Na+, K+, Al3+, Fe3+, Cl−, SO42− etc., was introduced into the cationic reverse flotation process of an iron ore. A series of bench flotation tests using iron ores, micro-flotation tests using pure fine quartz, water chemical analyses, and zeta potential measurement were conducted with the objective of identifying the possible influences of both cations and anions in the recycled tailing water on the flotation performance. The flotation results pointed out that the cation with higher valency had more severe influences on the recovery of iron oxides. The formation of the pH-dependent surface complexes on mineral surfaces, for example, Fe(OH)+, Fe(OH)2+, and Fe(OH)3 resulted from Fe3+ ions adsorption, contributed to the less negative zeta potentials of the quartz, and consequently weakened its interaction with the amine collector. It is worthy to note that SO42− ions seem to have a more positive effect on the recovery of iron oxides than Cl− ions. This is probably attributed to the formation of inner/outer- sphere surface complexes on the iron oxides, inhibiting the dissolution of the iron ions/species, and the coordination with these cations from the recycled tailing water, shielding their disturbances in the flotation.

Plant-Wide Control Framework for a Grinding Mill Circuit

This article proposes a generic plant-wide control framework that can be used to develop a hierarchical control structure (regulatory control, supervisory control, and optimization) to operate a single-stage closed grinding mill circuit in an economically optimal manner. An economic objective function is defined for the grinding mill circuit with reference to the economic objective of the larger mineral processing plant. A mineral processing plant in this study consists of a comminution and a separation circuit and excludes the extractive metallurgy at a metal refinery. The operational performance of a comminution circuit as represented by a single-stage grinding mill circuit, primarily depends on the performance of the grinding mill. Since grind curves define the operational performance range of a mill, grind curves are used to define the set points for the economic controlled variables for optimal steady-state operation. For a given metal price, processing cost, and transportation cost, the proposed str...

Water recovery via the removal of Cl− ion and total dissolved solids using electrodialysis in Gohar Zamin Iron Ore Concentrate Plant (GIOCP): modeling and simulation

The desalination process consists of a set of multi-step actions, which are conducted on saline water in order to remove excess salts and other minerals. In the desalination process, water is recovered, so that it would be suitable for industrial usage. In the present study, electrodialysis (ED) was used for desalination, especially for removing chloride (Cl-) ion and total dissolved solids (TDS), in Gohar Zamin Iron Ore Concentrate Plant (GIOCP). To optimize the influential factors in the removal of chloride and TDS in ED, the response surface methodology (RSM) was utilized. To this end, the D-optimal experimental design was applied to optimize the experiments. The effects of three independent parameters, including electrolysis time (A), consumption voltage (B), and initial concentration of chloride ion (C), were assess for the removal of chloride and TDS from recovered water. In addition, interactive and linear models were applied to determine the responses of chloride and TDS removal rates, respectively. The optimal operating conditions for the removal of chloride with 51.46% efficiency were obtained at the runtime of 30 minutes, consumption voltage of 12 V, and initial concentration of 300 ppm. Similarly, optimal TDS removal with 48.03% efficiency was achieved at the runtime of 30 minutes, consumption voltage of 12 V, and initial concentration of 300 ppm. According to the findings, ED was a highly reliable method for the removal of salts from water, as well as the high-quality recycling of water from mineral industries, especially in mineral processing plants.

Water-saving strategies in the mining industry – The potential of mineral processing simulators as a tool for their implementation

As the mining industry is facing an increasing number of issues related to its fresh water consumption, water-saving strategies are progressively being implemented in the mineral processing plants, often leading to variations in the process water chemistry. However, the impact of water chemistry variations on the process performance is rarely known beforehand, thus creating an obstacle to the implementation of those water-saving strategies. To tackle this problem, the effect the different dissolved species present in the process water have on the processing plant performance must be quantified, and this information must be digitalized in a practical and suitable form to be used in mineral processing simulators. To achieve this goal, a methodology to digitalize the influence of the process water composition on the flotation performance is presented in this paper. Using the flotation of a fluorite ore as case study, the relationship between process water composition and the flotation kinetics of that fluorite ore was determined. This relationship was digitalized in HSC Sim, a mineral processing simulator, turning it into a tool capable of simulating the flotation performance under a variety of process water compositions. Finally, the potential of this new tool to help implementing water-saving strategies on the mine site is discussed, and the challenges that need to be overcome in order to apply this tool at industrial scale are being addressed.

Stability analysis of an industrial salinity gradient solar pond

In this study, an assessment of salinity gradient stability of an industrial solar pond during two operation seasons (2014 and 2105) is presented. An industrial solar pond was constructed to supply a low-temperature heat (up to 60 °C) to achieve the temperature requirements of the flotation stage in a mineral processing plant (Solvay Minerales in Granada (Spain)). Along the first season, the salinity gradient was considered technically destroyed in April 2015 as the height to the upper convective zone increases from 0.3 m in July 2014 to 0.8 m. Two different methodologies based on the stratification principle were adapted and used in order to evaluate the salinity gradient stability. The boundaries of the salinity gradient appeared as the main source of instability. In the upper zone it is associated with the environmental parameters (e.g., rain and wind) that affect the upper convective zone and the upper layers of the non-convective zone that subsequently transmit the instability to the lower layers. In the bottom zone it is caused by operation parameters, such as the heat extraction or the addition of salt. Both methodologies provided similar predictive capability of stability results. However, the results provided by the stability analysis using the thermal and salinity expansion coefficients are a more useful tool in the control of the salinity gradient for solar pond technology.

Grinding and Flotation Optimization Using Operational Intelligence

In recent years, metal-producing companies have increased their investment in automation and technological innovation, embracing new opportunities to enable transformational change. Transformation to a digital plant can fundamentally revolutionize how industrial complexes operate. The abundant and growing quantity of real-time data and events collected in the grinding and flotation circuits in a mineral processing plant can be used to solve operational issues and optimize plant performance. A grade recovery model is used to identify the best operating conditions in real time. The strategy for increasing the value of instrumentation in current plants is reviewed. An optimal Gaudin size distribution model provides augmented information from traditional sensors to find the optimal grind cut size to reduce metal losses in the flotation circuits. Sensors in flotation circuits enable an estimate of the recovery and determination of the optimal froth depth and aeration using an air hold up flotation model. A strategy of classifying data for on-line generation of insights to using operational intelligence tools is described. The implementation of a recovery/grind strategy with industrial examples in non-ferrous mineral processing is presented.