behzad sedaghat - Academia.edu (original) (raw)

Papers by behzad sedaghat

Annually, gigagrams of cobalt residues, called hot filter cake (HFC), are produced from the Co ne... more Annually, gigagrams of cobalt residues, called hot filter cake (HFC), are produced from the Co neutralization step at Iranian zinc plants. With respect to the composition of HFC )i.e., 15-25% Zn, 0.5– 1.5% Co, 3–8% Mn(, it can be used as a secondary source of zinc, cobalt and manganese. In the present study, for the first time, treatment of HFC for separation and recovery of zinc has been studied. The residue was treated by employing selective alkaline leaching, in order to recover the maximum amount of zinc, followed by zinc electrowinning process. As a results, a solution was obtained from alkaline leaching under the optimum condition of 75 °C, sodium hydroxide of 8 M, solid-to-liquid ratio dm of 1:10, and stirring speed of 600 rpm, having zinc recovery of 88.5 %. In the following step, the electrowinning process, under the optimum working conditions being current density 350 A/m and time 10 hours, was carried out to produce a zinc powder with high purity of 99 percent. Finally, a...

Physicochemical Problems of Mineral Processing, 2013

The transport of heavy metals from mining disposal site to groundwater and surface water is one o... more The transport of heavy metals from mining disposal site to groundwater and surface water is one of the most serious environmental problems in the world. The transport of heavy metals such as Zn, Cd and Mn from leaching filter cake in RECo, Zanjan, Iran was examined by using column leaching. Parameters studied included: flow rate, pH of input solution and leaching time. In this study, the maxi- mum dissolution percents of Zn, Cd and Mn in input solution pH of 5 were 45.50 %, 53.97% and 19.94%, respectively. To statistically analysis the experimental results, SPSS14 software was employed. The results of SPSS 14 indicated that for the Zn, Cd and Mn dissolution, time and flow rate were found re- spectively, the effective parameters for the pollution in zinc leach residues.

Fizykochemiczne Problemy Mineralurgii - Physicochemical Problems of Mineral Processing

ABSTRACT

Transactions of the Indian Institute of Metals, 2015

ABSTRACT The assessment of heavy metal transition from Ni–Cd zinc plant residue (filtercake), as ... more ABSTRACT The assessment of heavy metal transition from Ni–Cd zinc plant residue (filtercake), as concentrations of zinc, nickel, cadmium and lead, requires quantification and a mathematical model that predicts their relative concentrations. Variability of filtercake characteristics may change the availability of heavy metals to the leachate or environment. In this study, a novel artificial neural network (ANN) model was constructed to predict Zn, Ni, Cd and Pb concentration leached from Ni–Cd filtercake in the leaching column. A three-layer backpropagation neural network was optimized and developed based on the Bayesian training algorithm. The inputs of this network are pH, flow rate of acidic influent, particle size and time. The geometry of the network giving the minimized mean square error (MSE) and sum of squared error (SSE) was a three-layer network having 18 neurons in the hidden layer (4🔞4) with a tangent sigmoid transfer function (tansig) at the hidden layer and linear transfer function (purelin) at the output layer. The fitting, regression, error and histogram plots for each response illustrate that there is a good agreement between the experimental data and the predicted values. Finally, a generalization of the developed model was carried out as 3D plots to evaluate the interactions of the input parameters on the transition of heavy metals to the leachate. With respect to these results, the effect of particle size on concentrations of zinc, nickel and lead are less (<3 mg/L) than that of cadmium (<3 mg/L). Furthermore, it was found that, at low flow rate, the concentrations of extracted metals are high due to enhancement of exposure residence time (between particles and leach solution).

The assessment of heavy metal transition from Ni-Cd zinc plant residue (filtercake), as concentra... more The assessment of heavy metal transition from Ni-Cd zinc plant residue (filtercake), as concentrations of zinc, nickel, cadmium and lead, requires quantification and a mathematical model that predicts their relative concentrations. Variability of filtercake characteristics may change the availability of heavy metals to the leachate or environment. In this study, a novel artificial neural network (ANN) model was constructed to predict Zn, Ni, Cd and Pb concentration leached from Ni-Cd filtercake in the leaching column. A three-layer backpropagation neural network was optimized and developed based on the Bayesian training algorithm. The inputs of this network are pH, flow rate of acidic influent, particle size and time. The geometry of the network giving the minimized mean square error (MSE) and sum of squared error (SSE) was a threelayer network having 18 neurons in the hidden layer (4🔞4) with a tangent sigmoid transfer function (tansig) at the hidden layer and linear transfer fun...

Annually, thousands tons of Co residues called Hot Filter Cake (HFC) are produced from Co neutral... more Annually, thousands tons of Co residues called Hot Filter Cake (HFC) are produced from Co neutralization step of Iranian zinc plants. With respect to the composition of HFC )i.e., 15-25% Zn, 0.5–1.5% Co, 3–8% Mn(, it can be used as a secondary source of zinc, cobalt and manganese. In the present study, for the first time, treatment of HFC for separation and recovery of zinc has been studied. The residue was treated by employing selective alkaline leaching, in order to recover the maximum amount of zinc, followed by zinc electrowinning process. Therefore, a solution was obtained from alkaline leaching under the optimum condition of 75 °C, sodium hydroxide of 8 M, S/L of 1:10, and stirring speed of 600 rpm, having zinc recovery of 88.5 %. In the following step, the electrowinning process under the optimum working conditions being as current density= 350 A/m2 and time= 10 hours, was carried out to produce the zinc powder with high purity of 99 percent. Finally, a simple and effective c...

Hydrometallurgy, 2013

ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was devel... more ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was developed after a two-step precipitation from leaching solution of copper oxidized ore, followed by copper concentrate leaching and electrowinning. The copper oxidized ore was primarily comminuted to a size below 100 μ, followed by acidic leaching at 25 °C for 40 min in H2SO4 solution, in which recovery of copper and iron were 95.95% and 12.63%, respectively. To remove iron impurity, at the first step of precipitation, NaOH was added to increase pH from about 1.5 to the optimum pH of 3.8 at 60 °C for 60 min; thus iron precipitation with recovery of over 80% was achieved. Copper precipitate as concentrate was obtained in the same method from iron-removed solution. The optimum condition of copper precipitation was found to be pH of 5.5, 25 °C and 45 min with 98.69% recovery. One of the advantages of this process was production of Na2SO4 with 99.1% purity after vaporization of the remaining solution from two-step precipitation. The obtained copper concentrate was leached at approximately the same condition of the first leaching step, and then the provided pregnant solution proceeded to an electrowinning cell with lead alloy anode contained antimony and steel sheet cathode under the following condition: temperature of 50 °C, reaction voltage of 2 V and current density of 300 Am− 2. Finally, a scale-up experiment was carried out and the copper cathode with 99.99% purity produced.

Elsevier Hydrometallurgy

ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was devel... more ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was developed after a two-step precipitation from leaching solution of copper oxidized ore, followed by copper concentrate leaching and electrowinning. The copper oxidized ore was primarily comminuted to a size below 100 μ, followed by acidic leaching at 25 °C for 40 min in H2SO4 solution, in which recovery of copper and iron were 95.95% and 12.63%, respectively. To remove iron impurity, at the first step of precipitation, NaOH was added to increase pH from about 1.5 to the optimum pH of 3.8 at 60 °C for 60 min; thus iron precipitation with recovery of over 80% was achieved. Copper precipitate as concentrate was obtained in the same method from iron-removed solution. The optimum condition of copper precipitation was found to be pH of 5.5, 25 °C and 45 min with 98.69% recovery. One of the advantages of this process was production of Na2SO4 with 99.1% purity after vaporization of the remaining solution from two-step precipitation. The obtained copper concentrate was leached at approximately the same condition of the first leaching step, and then the provided pregnant solution proceeded to an electrowinning cell with lead alloy anode contained antimony and steel sheet cathode under the following condition: temperature of 50 °C, reaction voltage of 2 V and current density of 300 Am− 2. Finally, a scale-up experiment was carried out and the copper cathode with 99.99% purity produced.

Recovery and separation of cobalt and manganese from one of zinc plant residues (ZPR), namely hot... more Recovery and separation of cobalt and manganese from one of zinc plant residues (ZPR), namely hot filter cake (HFC) using a hydrometallurgical process was studied. The process is carried out in four steps as follows: (1) washing zinc, (2) reductive leaching with hydrogen peroxide, (3) cadmium cementation with zinc powder and (4) separation of cobalt from manganese with beta naphthol. In this research, the separation between manganese and cobalt from the HFC using N-N reagent was investigated. The influence of several parameters on the course of the reaction such as N-N quantity, pH, temperature and reaction time was also examined. The optimum separation conditions were found to be N-N quantity: 8 times of stoichiometric value, time: 30 min, temperature: 25 °C and pH = 1.5. Using the optimized conditions, the cobalt and manganese precipitation was nearly 99% and 0%, respectively. A kinetic study of manganese precipitation through N-N reagent has been carried out to assess the effect of kinetics parameters. The data obtained for the leaching kinetics indicated that the precipitation of manganese is an ash diffusion controlled reaction and the reaction activation energy is equal to 1.4kJ/mol.

Annually, gigagrams of cobalt residues, called hot filter cake (HFC), are produced from the Co ne... more Annually, gigagrams of cobalt residues, called hot filter cake (HFC), are produced from the Co neutralization step at Iranian zinc plants. With respect to the composition of HFC )i.e., 15-25% Zn, 0.5– 1.5% Co, 3–8% Mn(, it can be used as a secondary source of zinc, cobalt and manganese. In the present study, for the first time, treatment of HFC for separation and recovery of zinc has been studied. The residue was treated by employing selective alkaline leaching, in order to recover the maximum amount of zinc, followed by zinc electrowinning process. As a results, a solution was obtained from alkaline leaching under the optimum condition of 75 °C, sodium hydroxide of 8 M, solid-to-liquid ratio dm of 1:10, and stirring speed of 600 rpm, having zinc recovery of 88.5 %. In the following step, the electrowinning process, under the optimum working conditions being current density 350 A/m and time 10 hours, was carried out to produce a zinc powder with high purity of 99 percent. Finally, a...

Physicochemical Problems of Mineral Processing, 2013

The transport of heavy metals from mining disposal site to groundwater and surface water is one o... more The transport of heavy metals from mining disposal site to groundwater and surface water is one of the most serious environmental problems in the world. The transport of heavy metals such as Zn, Cd and Mn from leaching filter cake in RECo, Zanjan, Iran was examined by using column leaching. Parameters studied included: flow rate, pH of input solution and leaching time. In this study, the maxi- mum dissolution percents of Zn, Cd and Mn in input solution pH of 5 were 45.50 %, 53.97% and 19.94%, respectively. To statistically analysis the experimental results, SPSS14 software was employed. The results of SPSS 14 indicated that for the Zn, Cd and Mn dissolution, time and flow rate were found re- spectively, the effective parameters for the pollution in zinc leach residues.

Fizykochemiczne Problemy Mineralurgii - Physicochemical Problems of Mineral Processing

ABSTRACT

Transactions of the Indian Institute of Metals, 2015

ABSTRACT The assessment of heavy metal transition from Ni–Cd zinc plant residue (filtercake), as ... more ABSTRACT The assessment of heavy metal transition from Ni–Cd zinc plant residue (filtercake), as concentrations of zinc, nickel, cadmium and lead, requires quantification and a mathematical model that predicts their relative concentrations. Variability of filtercake characteristics may change the availability of heavy metals to the leachate or environment. In this study, a novel artificial neural network (ANN) model was constructed to predict Zn, Ni, Cd and Pb concentration leached from Ni–Cd filtercake in the leaching column. A three-layer backpropagation neural network was optimized and developed based on the Bayesian training algorithm. The inputs of this network are pH, flow rate of acidic influent, particle size and time. The geometry of the network giving the minimized mean square error (MSE) and sum of squared error (SSE) was a three-layer network having 18 neurons in the hidden layer (4🔞4) with a tangent sigmoid transfer function (tansig) at the hidden layer and linear transfer function (purelin) at the output layer. The fitting, regression, error and histogram plots for each response illustrate that there is a good agreement between the experimental data and the predicted values. Finally, a generalization of the developed model was carried out as 3D plots to evaluate the interactions of the input parameters on the transition of heavy metals to the leachate. With respect to these results, the effect of particle size on concentrations of zinc, nickel and lead are less (<3 mg/L) than that of cadmium (<3 mg/L). Furthermore, it was found that, at low flow rate, the concentrations of extracted metals are high due to enhancement of exposure residence time (between particles and leach solution).

The assessment of heavy metal transition from Ni-Cd zinc plant residue (filtercake), as concentra... more The assessment of heavy metal transition from Ni-Cd zinc plant residue (filtercake), as concentrations of zinc, nickel, cadmium and lead, requires quantification and a mathematical model that predicts their relative concentrations. Variability of filtercake characteristics may change the availability of heavy metals to the leachate or environment. In this study, a novel artificial neural network (ANN) model was constructed to predict Zn, Ni, Cd and Pb concentration leached from Ni-Cd filtercake in the leaching column. A three-layer backpropagation neural network was optimized and developed based on the Bayesian training algorithm. The inputs of this network are pH, flow rate of acidic influent, particle size and time. The geometry of the network giving the minimized mean square error (MSE) and sum of squared error (SSE) was a threelayer network having 18 neurons in the hidden layer (4🔞4) with a tangent sigmoid transfer function (tansig) at the hidden layer and linear transfer fun...

Annually, thousands tons of Co residues called Hot Filter Cake (HFC) are produced from Co neutral... more Annually, thousands tons of Co residues called Hot Filter Cake (HFC) are produced from Co neutralization step of Iranian zinc plants. With respect to the composition of HFC )i.e., 15-25% Zn, 0.5–1.5% Co, 3–8% Mn(, it can be used as a secondary source of zinc, cobalt and manganese. In the present study, for the first time, treatment of HFC for separation and recovery of zinc has been studied. The residue was treated by employing selective alkaline leaching, in order to recover the maximum amount of zinc, followed by zinc electrowinning process. Therefore, a solution was obtained from alkaline leaching under the optimum condition of 75 °C, sodium hydroxide of 8 M, S/L of 1:10, and stirring speed of 600 rpm, having zinc recovery of 88.5 %. In the following step, the electrowinning process under the optimum working conditions being as current density= 350 A/m2 and time= 10 hours, was carried out to produce the zinc powder with high purity of 99 percent. Finally, a simple and effective c...

Hydrometallurgy, 2013

ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was devel... more ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was developed after a two-step precipitation from leaching solution of copper oxidized ore, followed by copper concentrate leaching and electrowinning. The copper oxidized ore was primarily comminuted to a size below 100 μ, followed by acidic leaching at 25 °C for 40 min in H2SO4 solution, in which recovery of copper and iron were 95.95% and 12.63%, respectively. To remove iron impurity, at the first step of precipitation, NaOH was added to increase pH from about 1.5 to the optimum pH of 3.8 at 60 °C for 60 min; thus iron precipitation with recovery of over 80% was achieved. Copper precipitate as concentrate was obtained in the same method from iron-removed solution. The optimum condition of copper precipitation was found to be pH of 5.5, 25 °C and 45 min with 98.69% recovery. One of the advantages of this process was production of Na2SO4 with 99.1% purity after vaporization of the remaining solution from two-step precipitation. The obtained copper concentrate was leached at approximately the same condition of the first leaching step, and then the provided pregnant solution proceeded to an electrowinning cell with lead alloy anode contained antimony and steel sheet cathode under the following condition: temperature of 50 °C, reaction voltage of 2 V and current density of 300 Am− 2. Finally, a scale-up experiment was carried out and the copper cathode with 99.99% purity produced.

Elsevier Hydrometallurgy

ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was devel... more ABSTRACT A step by step hydrometallurgical process for the production of copper cathode was developed after a two-step precipitation from leaching solution of copper oxidized ore, followed by copper concentrate leaching and electrowinning. The copper oxidized ore was primarily comminuted to a size below 100 μ, followed by acidic leaching at 25 °C for 40 min in H2SO4 solution, in which recovery of copper and iron were 95.95% and 12.63%, respectively. To remove iron impurity, at the first step of precipitation, NaOH was added to increase pH from about 1.5 to the optimum pH of 3.8 at 60 °C for 60 min; thus iron precipitation with recovery of over 80% was achieved. Copper precipitate as concentrate was obtained in the same method from iron-removed solution. The optimum condition of copper precipitation was found to be pH of 5.5, 25 °C and 45 min with 98.69% recovery. One of the advantages of this process was production of Na2SO4 with 99.1% purity after vaporization of the remaining solution from two-step precipitation. The obtained copper concentrate was leached at approximately the same condition of the first leaching step, and then the provided pregnant solution proceeded to an electrowinning cell with lead alloy anode contained antimony and steel sheet cathode under the following condition: temperature of 50 °C, reaction voltage of 2 V and current density of 300 Am− 2. Finally, a scale-up experiment was carried out and the copper cathode with 99.99% purity produced.

Recovery and separation of cobalt and manganese from one of zinc plant residues (ZPR), namely hot... more Recovery and separation of cobalt and manganese from one of zinc plant residues (ZPR), namely hot filter cake (HFC) using a hydrometallurgical process was studied. The process is carried out in four steps as follows: (1) washing zinc, (2) reductive leaching with hydrogen peroxide, (3) cadmium cementation with zinc powder and (4) separation of cobalt from manganese with beta naphthol. In this research, the separation between manganese and cobalt from the HFC using N-N reagent was investigated. The influence of several parameters on the course of the reaction such as N-N quantity, pH, temperature and reaction time was also examined. The optimum separation conditions were found to be N-N quantity: 8 times of stoichiometric value, time: 30 min, temperature: 25 °C and pH = 1.5. Using the optimized conditions, the cobalt and manganese precipitation was nearly 99% and 0%, respectively. A kinetic study of manganese precipitation through N-N reagent has been carried out to assess the effect of kinetics parameters. The data obtained for the leaching kinetics indicated that the precipitation of manganese is an ash diffusion controlled reaction and the reaction activation energy is equal to 1.4kJ/mol.