The copper extraction in shaking bioreactors was modeled and optimized using response surface methodology（RSM）. Influential parameters in the mesophilic bioleaching process of a low-grade copper ore including p H va...The copper extraction in shaking bioreactors was modeled and optimized using response surface methodology（RSM）. Influential parameters in the mesophilic bioleaching process of a low-grade copper ore including p H value, pulp density, and initial concentration of ferrous ions were comprehensively studied. The effect of leaching time on the response（copper extraction） at the 1st, 4th, 9th, 14 th and 22 nd days of treatment was modeled and examined. The central composite design methodology（CCD） was used as the design matrix to predict the optimal level of these parameters. Then, the model equation at the 22 nd day was optimized using the quadratic programming（QP） to maximize the total copper extraction within the studied experimental range. Under the optimal condition（initial p H value of 2.0, pulp density of 1.59%, and initial concentration of ferrous ions of 0 g/L）, the total copper extraction predicted by the model is 85.98% which is significantly close to that obtained from the experiment（84.57%）. The results show that RSM could be useful to predict the maximum copper extraction from a low-grade ore and investigate the effects of variables on the final response. Besides, a couple of statistically significant interactions are derived between p H value and pulp density as well as p H value and initial ferrous ion concentration which are precisely interpreted. However, there is no statistically significant interaction between the initial ferrous ion concentration and the pulp density. Additionally, the response at optimal levels of p H value and pulp density is found to be independent on the level of initial ferrous concentration.展开更多
This paper attempts to address some nonlinear differential equations which describe main mechanisms governing heap(bio)leaching process as an important metallurgical facility in mining and mineral processing industrie...This paper attempts to address some nonlinear differential equations which describe main mechanisms governing heap(bio)leaching process as an important metallurgical facility in mining and mineral processing industries.The Homotopy Perturbation Method(HPM),Finite Volume Method and Analytical(Laplace)Method have been employed to provide proper solutions for these equations.Comparison was made between the methods and agreement was close;considering the fact that the proposed solution in comparison with the others provided a remarkable accuracy in dealing with nonlinear problems associated with mining and mineral processing industries.The maximum error of HPM in relation to the analytical solution was 0.02.The numerical finite volume method incorporating a computational fluid dynamics model termed PHOENICS provided rational and accurate results;describing that many chemical and biological processes extremely affect the transportation mechanism of the aqueous compounds in a heap structure and subsequently on the process efficiency.Besides,all solution methods presented to simulate heap leaching process provided valuable information related to the time dependence concentrations of dissolved compounds.The results obtained from this study can be effectively applied to manage the heap leaching costs to make the process feasible.展开更多
文摘The copper extraction in shaking bioreactors was modeled and optimized using response surface methodology（RSM）. Influential parameters in the mesophilic bioleaching process of a low-grade copper ore including p H value, pulp density, and initial concentration of ferrous ions were comprehensively studied. The effect of leaching time on the response（copper extraction） at the 1st, 4th, 9th, 14 th and 22 nd days of treatment was modeled and examined. The central composite design methodology（CCD） was used as the design matrix to predict the optimal level of these parameters. Then, the model equation at the 22 nd day was optimized using the quadratic programming（QP） to maximize the total copper extraction within the studied experimental range. Under the optimal condition（initial p H value of 2.0, pulp density of 1.59%, and initial concentration of ferrous ions of 0 g/L）, the total copper extraction predicted by the model is 85.98% which is significantly close to that obtained from the experiment（84.57%）. The results show that RSM could be useful to predict the maximum copper extraction from a low-grade ore and investigate the effects of variables on the final response. Besides, a couple of statistically significant interactions are derived between p H value and pulp density as well as p H value and initial ferrous ion concentration which are precisely interpreted. However, there is no statistically significant interaction between the initial ferrous ion concentration and the pulp density. Additionally, the response at optimal levels of p H value and pulp density is found to be independent on the level of initial ferrous concentration.
文摘This paper attempts to address some nonlinear differential equations which describe main mechanisms governing heap(bio)leaching process as an important metallurgical facility in mining and mineral processing industries.The Homotopy Perturbation Method(HPM),Finite Volume Method and Analytical(Laplace)Method have been employed to provide proper solutions for these equations.Comparison was made between the methods and agreement was close;considering the fact that the proposed solution in comparison with the others provided a remarkable accuracy in dealing with nonlinear problems associated with mining and mineral processing industries.The maximum error of HPM in relation to the analytical solution was 0.02.The numerical finite volume method incorporating a computational fluid dynamics model termed PHOENICS provided rational and accurate results;describing that many chemical and biological processes extremely affect the transportation mechanism of the aqueous compounds in a heap structure and subsequently on the process efficiency.Besides,all solution methods presented to simulate heap leaching process provided valuable information related to the time dependence concentrations of dissolved compounds.The results obtained from this study can be effectively applied to manage the heap leaching costs to make the process feasible.
