The dissolution kinetics of the dissolution of iron ore in aqueous HCl/HNO3solution was studied. The elemental composition of the ore was carried out using the inductively coupled plasma-optical emission spectrophotom...The dissolution kinetics of the dissolution of iron ore in aqueous HCl/HNO3solution was studied. The elemental composition of the ore was carried out using the inductively coupled plasma-optical emission spectrophotometer (ICP-OES). The result showed that the iron ore contain;Fe (62.1%), O (21.7%), Cu (11.1%), Mg (2.39%), Na (1.51%), Mn (1.47%), K (0.78%), Ca (0.58%) and Zn (0.01%). It was determined that the dissolution rate increased with increased solution concentration, temperature, time and decreased particle size of the ore. The optimum conditions for effective dissolution of 88% of the iron ore were found to be 8 Mof the solution, 353 K, 100 min and ore particle size of less than 75 μm. The kinetic evaluation of the dissolution process was studied using three different shrinking core models (SCM);Film diffusion: kft =XB;interfacial chemical reaction krt =?1-(1-XB)1/3?and ash/product layer diffusion :??for spherical materials was performed. The results obtained showed that the rate determining step for the dissolution process was the product layer diffusion and therefore, the reaction followed this mechanism. The apparent activation energy (Ea) and the order of reaction were found to be 20.48 kJ/mol and 0.7 respectively.展开更多
Model for prediction of the concentration of tin extracted during potassium hydroxide leaching of cassiterite has been derived. The model: A = Nt1.53, indicates that the concentration tin extracted is dependent on the...Model for prediction of the concentration of tin extracted during potassium hydroxide leaching of cassiterite has been derived. The model: A = Nt1.53, indicates that the concentration tin extracted is dependent on the residence time. It was found that the validity of the model is rooted in the expression Log A = Log (Nt1.53). Tin extraction per unit time as obtained from experiment and derived model are 2.6666 and 2.6268 mg/min respectively. The maximum deviation of the model-predicted concentration of dissolved tin from the corresponding concentration obtained from the experiment was found to be less than 8%, which is quite within the acceptable deviation limit of experimental results and hence, impacting about 92% confidence coefficient on the model.展开更多
The extraction of Cobalt(II) from aqueous solution using 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone (HPMNP) in various organic solvents was studied as a function of pH and extractant concentration. Extraction into...The extraction of Cobalt(II) from aqueous solution using 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone (HPMNP) in various organic solvents was studied as a function of pH and extractant concentration. Extraction into organic chloroform phase was more efficient than with any other solvent. The extraction equilibrium constant was found to be log Kex= -7.04. Optimum conditions for extraction of Co(II) exist at pH of between 5.5 and 7.0, ionic strength of 0.3 Mand constant extractant concentration of 0.02 M. Shaking the organic Co(II) chelate complex with 0.2 Macid strips the Co(II) ions into the aqueous phase. It was established that Co(II) complex extracted is of composition, Co(PMNP)2.展开更多
文摘The dissolution kinetics of the dissolution of iron ore in aqueous HCl/HNO3solution was studied. The elemental composition of the ore was carried out using the inductively coupled plasma-optical emission spectrophotometer (ICP-OES). The result showed that the iron ore contain;Fe (62.1%), O (21.7%), Cu (11.1%), Mg (2.39%), Na (1.51%), Mn (1.47%), K (0.78%), Ca (0.58%) and Zn (0.01%). It was determined that the dissolution rate increased with increased solution concentration, temperature, time and decreased particle size of the ore. The optimum conditions for effective dissolution of 88% of the iron ore were found to be 8 Mof the solution, 353 K, 100 min and ore particle size of less than 75 μm. The kinetic evaluation of the dissolution process was studied using three different shrinking core models (SCM);Film diffusion: kft =XB;interfacial chemical reaction krt =?1-(1-XB)1/3?and ash/product layer diffusion :??for spherical materials was performed. The results obtained showed that the rate determining step for the dissolution process was the product layer diffusion and therefore, the reaction followed this mechanism. The apparent activation energy (Ea) and the order of reaction were found to be 20.48 kJ/mol and 0.7 respectively.
文摘Model for prediction of the concentration of tin extracted during potassium hydroxide leaching of cassiterite has been derived. The model: A = Nt1.53, indicates that the concentration tin extracted is dependent on the residence time. It was found that the validity of the model is rooted in the expression Log A = Log (Nt1.53). Tin extraction per unit time as obtained from experiment and derived model are 2.6666 and 2.6268 mg/min respectively. The maximum deviation of the model-predicted concentration of dissolved tin from the corresponding concentration obtained from the experiment was found to be less than 8%, which is quite within the acceptable deviation limit of experimental results and hence, impacting about 92% confidence coefficient on the model.
文摘The extraction of Cobalt(II) from aqueous solution using 1-phenyl-3-methyl-4-(p-nitrobenzoyl)pyrazolone (HPMNP) in various organic solvents was studied as a function of pH and extractant concentration. Extraction into organic chloroform phase was more efficient than with any other solvent. The extraction equilibrium constant was found to be log Kex= -7.04. Optimum conditions for extraction of Co(II) exist at pH of between 5.5 and 7.0, ionic strength of 0.3 Mand constant extractant concentration of 0.02 M. Shaking the organic Co(II) chelate complex with 0.2 Macid strips the Co(II) ions into the aqueous phase. It was established that Co(II) complex extracted is of composition, Co(PMNP)2.
