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Kamran Haghighi H.,Amirkabir University of Technology | Kamran Haghighi H.,University of Applied Science and Technology of Iran | Rafie M.,University of Zanjan | Moradkhani D.,University of Zanjan | And 2 more authors.
Transactions of the Indian Institute of Metals | Year: 2015

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 (4:18:4) 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). © 2015, The Indian Institute of Metals - IIM.

Kamran Haghighi H.,Amirkabir University of Technology | Moradkhani D.,University of Zanjan | Sedaghat B.,Research and Engineering Company for Non ferrous Metals RECo | Rajaie Najafabadi M.,Amirkabir University of Technology | Behnamfard A.,Amirkabir University of Technology
Hydrometallurgy | Year: 2013

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. © 2012 Elsevier B.V.

Moradkhani D.,Research and Engineering Company for Non ferrous Metals RECo | Moradkhani D.,ZINC Inc | Moradkhani D.,University of Zanjan | Hajisoleimani B.,Research and Engineering Company for Non ferrous Metals RECo | And 2 more authors.
Pb Zn 2010 - Lead-Zinc 2010 Symposium, Held in Conjunction with COM 2010 | Year: 2010

In this study, the effect of cationic collector (coco-alcyl-amine-acetate) concentration, for optimization of zinc recovery and grade response in flotation by mixed (KAX-Armac C) or catanionic collectors, has been investigated. In the view of above, the orthogonal array design L18 (21× 37) according to the Taguchi quality engineering method that comprises one parameter at two levels and seven parameters at three levels, was chosen. The parameters were sodium silicate, starch, sodium sulfide, xanthate (in two stage) and Armac C concentrations, pH and flotation time. The sample was obtained from Angouran mine and its XRD analysis showed that the ore contains predominant phases of zinc non-sulfide and calcite minerals. Statistical analysis and S/N evaluation methods were also employed to determine the relationship between experimental conditions and yield levels. According to the results, Armac C concentration has a maximum effect on the zinc recovery and grade responses in the process. Under optimum conditions, zinc recovery and grade in concentrate were 82.69% and 41.68%, respectively.

Safarzadeh M.S.,ZINC Inc | Safarzadeh M.S.,Research and Engineering Company for Non ferrous Metals RECo | Moradkhani D.,ZINC Inc | Moradkhani D.,Research and Engineering Company for Non ferrous Metals RECo | Moradkhani D.,University of Zanjan
Separation and Purification Technology | Year: 2010

Addressed is the effect of heat treatment on the dissolution behavior of zinc, cadmium and nickel from Cd-Ni zinc plant residues. The proposal was considered for possible positive effect of heat treatment on the separation of nickel present in the residue, due to some phase transformations. The leaching experiments were carried out with the heat-treated residues at identical leaching conditions. The residues were heat treated at 100-1000 °C for 1 h and water-leached after subsequent cooling down to the room temperature. The results obviously showed that the heat treatment necessarily reduces the dissolution of zinc but does not affect the dissolution of cadmium. However, the recovery of nickel was increased by 83.80% upon the temperature increase from 25 to 800 °C, whereas at temperatures above 800 °C, the recovery of nickel did not change. This work offers a possible vehicle for the separation of nickel from the residues. The increase in nickel dissolution was attributed to the formation of water-soluble nickel sulfate which was further verified by the XRD detection. © 2010 Elsevier B.V. All rights reserved.

Moradkhani D.,University of Zanjan | Sedaghat B.,Research and Engineering Company for Non ferrous Metals RECo | Khodakarami M.,Research and Engineering Company for Non ferrous Metals RECo | Khodakarami M.,Imam Khomeini International University | Ataei I.,Research and Engineering Company for Non ferrous Metals RECo
Physicochemical Problems of Mineral Processing | Year: 2014

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.

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