The effect of Na2SO3 as a pyrite depressant in NaCl and KCl saline media and the presence of kaol... more The effect of Na2SO3 as a pyrite depressant in NaCl and KCl saline media and the presence of kaolinite were evaluated by zeta potential tests. Chalcopyrite was also included in the study, because pyrite usually accompanies this mineral. Subsequently, the floatability results of both minerals in the NaCl solution were optimized based on the design of experiments (DoE). The Box-Behnken DoE was applied considering the percentage of kaolinite (X1), collector dose (X2), and depressant dose (X3) as factors. The results were modeled using artificial neural networks (ANNs) to construct contour plots and to determine the optimal conditions. In particular, maximization of the mass recovery of chalcopyrite and minimization of that of pyrite were sought. The particle swarm optimization algorithm was used as an optimization technique. The results indicated that the optimal conditions to maximize the floatability of chalcopyrite were kaolinite 6.85%, collector dose 3.58 × 10-3 mol/dm 3 , and depressant dose 3.49 × 10-5 mol/dm 3. On the contrary, the optimal conditions to minimize the floatability of pyrite were 5% kaolinite, collector dose 5 × 10-4 mol/dm 3 , and depressant dose 6.4 × 10-5 mol/dm 3. Under these conditions, the mass recoveries of chalcopyrite and pyrite were 66.1% and 14.0%, respectively. The results also indicated that the presence of kaolinite negatively affects the flotation of chalcopyrite, while the effect of Na2SO3 is not significant. In general, the findings suggest that Na2SO3 is a viable alternative to consider as a pyrite depressant in saline environments.
Physicochemical Problems of Mineral Processing, 2018
Depression of pyrite by dextrin in flotation with xanthates has been studied. The adsorption of d... more Depression of pyrite by dextrin in flotation with xanthates has been studied. The adsorption of dextrin and xanthates at the pyrite/aqueous solution interface has been investigated through electrokinetics, Raman spectroscopy and batch adsorption studies using oxidized pyrite. Microflotation studies were undertaken to evaluate the pyrite depression with dextrin using ethyl and propyl xanthates as the collector. The surface density of ferric hydroxide on pyrite depended on pH and was highest about the iep (pH 7.5) of the oxidized pyrite. Dextrin adsorption was directly related to the surface density of ferric hydroxide and took place through two steps suggesting two adsorption mechanisms on ferric hydroxide. Xanthate adsorption as dixanthogen occurred along with ferric hydroxide dissolution causing partial dextrin desorption from the pyrite surface; consequently, coadsorption of xanthate and dextrin occurred on the surface. Depression of pyrite flotation with xanthate was determined b...
The design of a flotation circuit based on optimization techniques requires a superstructure for ... more The design of a flotation circuit based on optimization techniques requires a superstructure for representing a set of alternatives, a mathematical model for modeling the alternatives, and an optimization technique for solving the problem. The optimization techniques are classified into exact and approximate methods. The first has been widely used. However, the probability of finding an optimal solution decreases when the problem size increases. Genetic algorithms have been the approximate method used for designing flotation circuits when the studied problems were small. The Tabu-search algorithm (TSA) is an approximate method used for solving combinatorial optimization problems. This algorithm is an adaptive procedure that has the ability to employ many other methods. The TSA uses short-term memory to prevent the algorithm from being trapped in cycles. The TSA has many practical advantages but has not been used for designing flotation circuits. We propose using the TSA for solving ...
Multiphase systems are important in minerals processing, and usually include solid–solid and soli... more Multiphase systems are important in minerals processing, and usually include solid–solid and solid–fluid systems, such as in wet grinding, flotation, dewatering, and magnetic separation, among several other unit operations. In this paper, the current trends in the process system engineering tasks of modeling, design, and optimization in multiphase systems, are analyzed. Different scales of size and time are included, and therefore, the analysis includes modeling at the molecular level (molecular dynamic modeling) and unit operation level (e.g., computational fluid dynamic, CFD), and the application of optimization for the design of a plant. New strategies for the modeling, design, and optimization of multiphase systems are also included, with a strong focus on the application of artificial intelligence (AI) and the combination of experimentation and modeling with response surface methodology (RSM). The integration of different modeling techniques such as CFD with discrete element si...
The heap leaching of minerals is one of the more commonly used processes in the mining industry. ... more The heap leaching of minerals is one of the more commonly used processes in the mining industry. This process has been modeled by many authors. However, the validation, verification, and implementation of these models are difficult since there is uncertainty about the operating conditions and the leaching model parameters. This work uses the uncertainty quantification, based on uncertainty and sensitivity analysis, for studying the model strength against uncertainties in heap leaching. The uncertainty analysis (UA) is used to quantify the effect of the magnitude of the uncertainties of the input variables on the recovery of heap leaching. Global sensitivity analysis (GSA) is used to study the nature of connections between the recovery and input variables of the leaching model. In addition, GSA facilitates the detection of whether a leaching model is over-parameterized. The information obtained allows studying some applications of the kinetic model. The Mellado et al. kinetic model is used as an example. The UA results indicate that the kinetic model can estimate the recovery behavior considering the full range of uncertainties of input variables. The GSA indicates that the kinetic model is over-parameterized on the uncertainties range considered; this conclusion contradicts the results when the local sensitivity analysis is used. However, the model shows a good correlation between the results of GSA and the kinetic behavior of heap leaching. In addition, the kinetic model presents versatility because it allows the determination of operating regions for heap leaching.
In this work it is suggested to develop a theory for chemical products, that defines the bases an... more In this work it is suggested to develop a theory for chemical products, that defines the bases and serves to guide and put in order the development of knowledge in the area. A nature representation of chemical products is carried out based on the simple observation that a chemical product is a system consisted of different chemical substances, and that it is manufactured for one or more purposes, in other words, it is formed by components, an organization and an environment. This representation is used to identify different kinds of chemical products design problems.
... 18th European Symposium on Computer Aided Process Engineering -ESCAPE18 Bertrand Braunschweig... more ... 18th European Symposium on Computer Aided Process Engineering -ESCAPE18 Bertrand Braunschweig and Xavier Joulia (Editors ... Let denote C, ={ (T,Q) IQ = FCp(I;n -T), r; STS t; las the Hohmann/Lockhart curve for a hot stream h, then the hot composite curve can be defined ...
Modelling and simulation of a flotation circuit usually involve identifying the structure of the ... more Modelling and simulation of a flotation circuit usually involve identifying the structure of the flowsheet, deriving model equations to represent each operation, and solving the resulting total model equations according to one of various available simulation strategies. The flotation circuit synthesis problem determines the type of operations and their sequence needed to achieve the extraction of valuable metals from the
Although heap leaching has become established as the technology for treatment of some copper, gol... more Although heap leaching has become established as the technology for treatment of some copper, gold, and zinc minerals, as well as its extension to the treatment of other types of minerals such as saltpeter and mine tailings, little study has been made on the optimization of this technology. Usually the operation of heap leaching is carried out until the maximum recovery has been obtained, or until observing that the concentration in the output solution of the heap exhibits no further extraction. The present study makes an analysis to determine if these criteria present the best conditions from the economic standpoint. Two variables are examined including, (1) leaching time, and (2) height of the heap, at a copper mineral treatment plant. The results of the study showed that the design (height of the heap), and planning of the operation (operational time) were interactive factors, and that maximum recovery was not necessarily the best measure of operational efficiency based on economic considerations.
Heap leaching is a technology for which there is great interest in developing mathematical models... more Heap leaching is a technology for which there is great interest in developing mathematical models that allow one to simulate, design and optimise the underlying process. Recently, the authors have presented analytical models for heap leaching that describe time scales for the particle and the heap in a rather simple model but with enough accuracy to be applied in the planning, optimisation, control and design of heap leaching. The simplicity of these models allows us to overcome the mathematical complexities of partial differential equation-based models and the error of empirical models. In this work, we present these analytical models, and then show how uncertainty in the input variables and parameters affects the response of the process by comparing the response curve with fixed parameters to the ones with uncertainty. Here we present simulation experiments of heap leaching processes under uncertainties based upon analytical models and using Monte Carlo techniques. We conclude that, in some cases, there exists an important influence of the input variables' uncertainty on the response of the heap leaching process.
In this paper we present some considerations on the computation of optimal flow rates for the hea... more In this paper we present some considerations on the computation of optimal flow rates for the heap leaching process of solid reactants from porous pellets. We use a model already published by authors, which is suitable in applications where the scale-up is necessary. This approach allows to obtain better flow rates. Novelty of this approach is the simple form of
The technology of solvent extraction in the hydrometallurgical industry typically consists of two... more The technology of solvent extraction in the hydrometallurgical industry typically consists of two circuits, an extraction circuit and a stripping circuit, coupled by a common solvent. Process flow patterns regularly range from single-solvent circulation loops to schemes employing solvent and aqueous bypass or intermediate solvent recycle. The design of these processes using graphical methods runs into a series of complications produced by the coupling of the flow loops. In this paper, a graphical method is developed for the preliminary analysis of different flow structures for these coupled circuits. The method is simple and can be performed by hand. Several examples are presented to illustrate the utility of the proposed method.
In this paper we present an alternative method based on analytical and numerical solutions for so... more In this paper we present an alternative method based on analytical and numerical solutions for solving the differential equations which describe heap leaching of one or more solid reactants from porous pellets. We propose to use analytical solutions for the differential equations which describe rate dissolutions along the pores and the surface of the particles under suitable regularity conditions. Moreover,
ABSTRACT AbstractIn this paper we present analytical models suitable for scaling up the heap leac... more ABSTRACT AbstractIn this paper we present analytical models suitable for scaling up the heap leaching process of solid reactants from porous pellets. The models are based on first order ordinary differential equations together with some constitutive relations derived from models based on ordinary and partial differential equations and other relations based on insight. The models are suitable for applications in which the scale-up is neccesary. This approach allows to obtain accurate solutions for actual industry heap leaching operations. Novelty of this approach is the simple form of the models and its accuracy as compared with more complex models. Due to the models simplicity, they can be used for analysis, design, control and optimization of heap leaching processes without mathematical complexities. The models include the effect of heap height, particle sizes, flow rates, and several operation-design variables. Finally, some numerical experiments which confirm our theory are presented.
A flowsheet synthesis methodology is presented for the design of fractional crystallization proce... more A flowsheet synthesis methodology is presented for the design of fractional crystallization processes. The methodology is based on four interconnected/nested networks. The first network is derived by identifying a set of thermodynamic states providing a basis for feasible separation alternatives. In this network, the nodes correspond to multiple saturation points, solute intermediates, and process feeds and end products. The second
The environmental problems generated by waste from the mining industry in the mineral extraction ... more The environmental problems generated by waste from the mining industry in the mineral extraction for business purposes are known worldwide. The aim of this work is to evaluate the microalga Muriellopsis sp. as a potential remover of metallic ions such as copper (Cu+2), zinc (Zn+2) and iron (Fe+2), pollutants of AMD type waters. For this, the removal of these ions was verified in artificial acid waters with high concentrations of the ions under examination. As well as, the removal was evaluated in waters obtained from areas contaminated by mining waste. The results showed that Muriellopsis sp. removed metals in waters with high concentrations after 4 to 12 hours and showed tolerance to pH between 3 to 5. These results allow proposing this species as a potential bioremediator for areas contaminated by mining activity. In this work, some potential alternatives for application in damaged areas are proposed as a decontamination plan and future prevention.
The effect of Na2SO3 as a pyrite depressant in NaCl and KCl saline media and the presence of kaol... more The effect of Na2SO3 as a pyrite depressant in NaCl and KCl saline media and the presence of kaolinite were evaluated by zeta potential tests. Chalcopyrite was also included in the study, because pyrite usually accompanies this mineral. Subsequently, the floatability results of both minerals in the NaCl solution were optimized based on the design of experiments (DoE). The Box-Behnken DoE was applied considering the percentage of kaolinite (X1), collector dose (X2), and depressant dose (X3) as factors. The results were modeled using artificial neural networks (ANNs) to construct contour plots and to determine the optimal conditions. In particular, maximization of the mass recovery of chalcopyrite and minimization of that of pyrite were sought. The particle swarm optimization algorithm was used as an optimization technique. The results indicated that the optimal conditions to maximize the floatability of chalcopyrite were kaolinite 6.85%, collector dose 3.58 × 10-3 mol/dm 3 , and depressant dose 3.49 × 10-5 mol/dm 3. On the contrary, the optimal conditions to minimize the floatability of pyrite were 5% kaolinite, collector dose 5 × 10-4 mol/dm 3 , and depressant dose 6.4 × 10-5 mol/dm 3. Under these conditions, the mass recoveries of chalcopyrite and pyrite were 66.1% and 14.0%, respectively. The results also indicated that the presence of kaolinite negatively affects the flotation of chalcopyrite, while the effect of Na2SO3 is not significant. In general, the findings suggest that Na2SO3 is a viable alternative to consider as a pyrite depressant in saline environments.
Physicochemical Problems of Mineral Processing, 2018
Depression of pyrite by dextrin in flotation with xanthates has been studied. The adsorption of d... more Depression of pyrite by dextrin in flotation with xanthates has been studied. The adsorption of dextrin and xanthates at the pyrite/aqueous solution interface has been investigated through electrokinetics, Raman spectroscopy and batch adsorption studies using oxidized pyrite. Microflotation studies were undertaken to evaluate the pyrite depression with dextrin using ethyl and propyl xanthates as the collector. The surface density of ferric hydroxide on pyrite depended on pH and was highest about the iep (pH 7.5) of the oxidized pyrite. Dextrin adsorption was directly related to the surface density of ferric hydroxide and took place through two steps suggesting two adsorption mechanisms on ferric hydroxide. Xanthate adsorption as dixanthogen occurred along with ferric hydroxide dissolution causing partial dextrin desorption from the pyrite surface; consequently, coadsorption of xanthate and dextrin occurred on the surface. Depression of pyrite flotation with xanthate was determined b...
The design of a flotation circuit based on optimization techniques requires a superstructure for ... more The design of a flotation circuit based on optimization techniques requires a superstructure for representing a set of alternatives, a mathematical model for modeling the alternatives, and an optimization technique for solving the problem. The optimization techniques are classified into exact and approximate methods. The first has been widely used. However, the probability of finding an optimal solution decreases when the problem size increases. Genetic algorithms have been the approximate method used for designing flotation circuits when the studied problems were small. The Tabu-search algorithm (TSA) is an approximate method used for solving combinatorial optimization problems. This algorithm is an adaptive procedure that has the ability to employ many other methods. The TSA uses short-term memory to prevent the algorithm from being trapped in cycles. The TSA has many practical advantages but has not been used for designing flotation circuits. We propose using the TSA for solving ...
Multiphase systems are important in minerals processing, and usually include solid–solid and soli... more Multiphase systems are important in minerals processing, and usually include solid–solid and solid–fluid systems, such as in wet grinding, flotation, dewatering, and magnetic separation, among several other unit operations. In this paper, the current trends in the process system engineering tasks of modeling, design, and optimization in multiphase systems, are analyzed. Different scales of size and time are included, and therefore, the analysis includes modeling at the molecular level (molecular dynamic modeling) and unit operation level (e.g., computational fluid dynamic, CFD), and the application of optimization for the design of a plant. New strategies for the modeling, design, and optimization of multiphase systems are also included, with a strong focus on the application of artificial intelligence (AI) and the combination of experimentation and modeling with response surface methodology (RSM). The integration of different modeling techniques such as CFD with discrete element si...
The heap leaching of minerals is one of the more commonly used processes in the mining industry. ... more The heap leaching of minerals is one of the more commonly used processes in the mining industry. This process has been modeled by many authors. However, the validation, verification, and implementation of these models are difficult since there is uncertainty about the operating conditions and the leaching model parameters. This work uses the uncertainty quantification, based on uncertainty and sensitivity analysis, for studying the model strength against uncertainties in heap leaching. The uncertainty analysis (UA) is used to quantify the effect of the magnitude of the uncertainties of the input variables on the recovery of heap leaching. Global sensitivity analysis (GSA) is used to study the nature of connections between the recovery and input variables of the leaching model. In addition, GSA facilitates the detection of whether a leaching model is over-parameterized. The information obtained allows studying some applications of the kinetic model. The Mellado et al. kinetic model is used as an example. The UA results indicate that the kinetic model can estimate the recovery behavior considering the full range of uncertainties of input variables. The GSA indicates that the kinetic model is over-parameterized on the uncertainties range considered; this conclusion contradicts the results when the local sensitivity analysis is used. However, the model shows a good correlation between the results of GSA and the kinetic behavior of heap leaching. In addition, the kinetic model presents versatility because it allows the determination of operating regions for heap leaching.
In this work it is suggested to develop a theory for chemical products, that defines the bases an... more In this work it is suggested to develop a theory for chemical products, that defines the bases and serves to guide and put in order the development of knowledge in the area. A nature representation of chemical products is carried out based on the simple observation that a chemical product is a system consisted of different chemical substances, and that it is manufactured for one or more purposes, in other words, it is formed by components, an organization and an environment. This representation is used to identify different kinds of chemical products design problems.
... 18th European Symposium on Computer Aided Process Engineering -ESCAPE18 Bertrand Braunschweig... more ... 18th European Symposium on Computer Aided Process Engineering -ESCAPE18 Bertrand Braunschweig and Xavier Joulia (Editors ... Let denote C, ={ (T,Q) IQ = FCp(I;n -T), r; STS t; las the Hohmann/Lockhart curve for a hot stream h, then the hot composite curve can be defined ...
Modelling and simulation of a flotation circuit usually involve identifying the structure of the ... more Modelling and simulation of a flotation circuit usually involve identifying the structure of the flowsheet, deriving model equations to represent each operation, and solving the resulting total model equations according to one of various available simulation strategies. The flotation circuit synthesis problem determines the type of operations and their sequence needed to achieve the extraction of valuable metals from the
Although heap leaching has become established as the technology for treatment of some copper, gol... more Although heap leaching has become established as the technology for treatment of some copper, gold, and zinc minerals, as well as its extension to the treatment of other types of minerals such as saltpeter and mine tailings, little study has been made on the optimization of this technology. Usually the operation of heap leaching is carried out until the maximum recovery has been obtained, or until observing that the concentration in the output solution of the heap exhibits no further extraction. The present study makes an analysis to determine if these criteria present the best conditions from the economic standpoint. Two variables are examined including, (1) leaching time, and (2) height of the heap, at a copper mineral treatment plant. The results of the study showed that the design (height of the heap), and planning of the operation (operational time) were interactive factors, and that maximum recovery was not necessarily the best measure of operational efficiency based on economic considerations.
Heap leaching is a technology for which there is great interest in developing mathematical models... more Heap leaching is a technology for which there is great interest in developing mathematical models that allow one to simulate, design and optimise the underlying process. Recently, the authors have presented analytical models for heap leaching that describe time scales for the particle and the heap in a rather simple model but with enough accuracy to be applied in the planning, optimisation, control and design of heap leaching. The simplicity of these models allows us to overcome the mathematical complexities of partial differential equation-based models and the error of empirical models. In this work, we present these analytical models, and then show how uncertainty in the input variables and parameters affects the response of the process by comparing the response curve with fixed parameters to the ones with uncertainty. Here we present simulation experiments of heap leaching processes under uncertainties based upon analytical models and using Monte Carlo techniques. We conclude that, in some cases, there exists an important influence of the input variables' uncertainty on the response of the heap leaching process.
In this paper we present some considerations on the computation of optimal flow rates for the hea... more In this paper we present some considerations on the computation of optimal flow rates for the heap leaching process of solid reactants from porous pellets. We use a model already published by authors, which is suitable in applications where the scale-up is necessary. This approach allows to obtain better flow rates. Novelty of this approach is the simple form of
The technology of solvent extraction in the hydrometallurgical industry typically consists of two... more The technology of solvent extraction in the hydrometallurgical industry typically consists of two circuits, an extraction circuit and a stripping circuit, coupled by a common solvent. Process flow patterns regularly range from single-solvent circulation loops to schemes employing solvent and aqueous bypass or intermediate solvent recycle. The design of these processes using graphical methods runs into a series of complications produced by the coupling of the flow loops. In this paper, a graphical method is developed for the preliminary analysis of different flow structures for these coupled circuits. The method is simple and can be performed by hand. Several examples are presented to illustrate the utility of the proposed method.
In this paper we present an alternative method based on analytical and numerical solutions for so... more In this paper we present an alternative method based on analytical and numerical solutions for solving the differential equations which describe heap leaching of one or more solid reactants from porous pellets. We propose to use analytical solutions for the differential equations which describe rate dissolutions along the pores and the surface of the particles under suitable regularity conditions. Moreover,
ABSTRACT AbstractIn this paper we present analytical models suitable for scaling up the heap leac... more ABSTRACT AbstractIn this paper we present analytical models suitable for scaling up the heap leaching process of solid reactants from porous pellets. The models are based on first order ordinary differential equations together with some constitutive relations derived from models based on ordinary and partial differential equations and other relations based on insight. The models are suitable for applications in which the scale-up is neccesary. This approach allows to obtain accurate solutions for actual industry heap leaching operations. Novelty of this approach is the simple form of the models and its accuracy as compared with more complex models. Due to the models simplicity, they can be used for analysis, design, control and optimization of heap leaching processes without mathematical complexities. The models include the effect of heap height, particle sizes, flow rates, and several operation-design variables. Finally, some numerical experiments which confirm our theory are presented.
A flowsheet synthesis methodology is presented for the design of fractional crystallization proce... more A flowsheet synthesis methodology is presented for the design of fractional crystallization processes. The methodology is based on four interconnected/nested networks. The first network is derived by identifying a set of thermodynamic states providing a basis for feasible separation alternatives. In this network, the nodes correspond to multiple saturation points, solute intermediates, and process feeds and end products. The second
The environmental problems generated by waste from the mining industry in the mineral extraction ... more The environmental problems generated by waste from the mining industry in the mineral extraction for business purposes are known worldwide. The aim of this work is to evaluate the microalga Muriellopsis sp. as a potential remover of metallic ions such as copper (Cu+2), zinc (Zn+2) and iron (Fe+2), pollutants of AMD type waters. For this, the removal of these ions was verified in artificial acid waters with high concentrations of the ions under examination. As well as, the removal was evaluated in waters obtained from areas contaminated by mining waste. The results showed that Muriellopsis sp. removed metals in waters with high concentrations after 4 to 12 hours and showed tolerance to pH between 3 to 5. These results allow proposing this species as a potential bioremediator for areas contaminated by mining activity. In this work, some potential alternatives for application in damaged areas are proposed as a decontamination plan and future prevention.
Uploads
Papers by Luis Cisternas