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Papers by archana agrawal

Colloids and Surfaces, 1990

Colloids and Surfaces, 46 (1990) 239-253 239 Elsevier Science Publishers BV, Amsterdam - Printed ... more Colloids and Surfaces, 46 (1990) 239-253 239 Elsevier Science Publishers BV, Amsterdam - Printed in The Netherlands Equilibrium Studies for the Sorption of Cu" on Lanthanum Diethanolamine - A Chelating Material JP RAWAT, ANEES AHMAD and ARCHANA AGRAWAL ...

Waste Management & Research, 2006

To recover pigment grade TiO2, operating plants all over the world use chemical processes. Slag-b... more To recover pigment grade TiO2, operating plants all over the world use chemical processes. Slag-based technology is considered to be attractive because of low waste generation and low chemical cost due to high titanium content and is poised to replace the conventional technology. This paper provides a review of the slag-based technology with the specific aim to produce leachable slag and achieving high titania yield from recovered wastes. Leachable oxides of the lower oxidation state, such as TiO and Ti2O3, facilitate the leaching process. However, during smelting these oxides increase the viscosity of the slag. Formation of titanium carbide or carbonitride is also not desirable as it leads to resistance to the leaching of titanium. This report highlights the problems and their possible solutions to obtain leachable slag.

Waste Management & Research, 2004

Almost all metallurgical processes are associated with the generation of wastes and residues that... more Almost all metallurgical processes are associated with the generation of wastes and residues that may be hazardous or non-hazardous in nature depending upon the criteria specified by institutions such as the US Environment Protection Agency, etc. Wastes containing heavy and toxic metals such as arsenic, cadmium, chromium, nickel, lead, copper, mercury, zinc, etc., that are present beyond permissible limits deemed to be treated or disposed of, and non-hazardous wastes can be utilized for metal recovery or safe disposal. Zinc is in growing demand all over the world. In India, a major amount of zinc is imported and therefore processing of zinc secondaries will assist in satisfying the gap between demand and supply to some extent. This report mainly focuses on the current practices and recent trends on the secondary processing of zinc. Attempts made by various laboratories to develop ecofriendly processes for the recovery of zinc from secondary raw materials are also described and discu...

Minerals Engineering, 2005

Mikrochimica Acta, 1994

A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic sur... more A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5.6 is reported. The complex is extracted into a chloroform-propan-2-ol (4:1) mixture and shows maximum absorbance at 520 nm. Beer's law is obeyed in the range 1–14 µg/ml with an average molar absorptivity of 15800 l mol-1 cm-1. The molar ratio

Journal of Hazardous Materials, 2009

Every metal and metallurgical industry is associated with the generation of waste, which may be a... more Every metal and metallurgical industry is associated with the generation of waste, which may be a solid, liquid or gaseous in nature. Their impacts on the ecological bodies are noticeable due to their complex and hazardous nature affecting the living and non-living environment which is an alarming issue to the environmentalist. The increasingly stringent regulations regarding the discharge of acid and metal into the environment, and the increasing stress upon the recycling/reuse of these effluents after proper treatment have focused the interest of the research community on the development of new approaches for the recovery of acid and metals from industrial wastes. This paper is a critical review on the acidic waste streams generated from steel and electroplating industries particularly from waste pickle liquor and spent bleed streams. Various aspects on the generation of these streams and the methods used for their treatment either for the recovery of acid for reuse or disposal are being dealt with. Major stress is laid upon the hydrometallurgical methods such as solvent extraction.

Journal of Environmental Management, 2013

Recovery of valuable materials/metals from waste goes hand in hand with environmental protection.... more Recovery of valuable materials/metals from waste goes hand in hand with environmental protection. This paper deals with the development of a process for the recovery of metals such as Mo, V, Ni, Al from spent hydroprocessing catalyst which may otherwise cause a nuisance if dumped untreated. A detailed study on the separation of molybdenum and vanadium from the leach solution of spent hydroprocessing catalyst of composition: 27.15% MoO₃, 1.7% V₂O₅, 3.75% NiO, 54.3% Al₂O₃, 2.3% SiO₂ and 10.4% LOI is reported in this paper. The catalyst was subjected to roasting under oxidizing atmosphere at a temperature of about 550 °C and leaching in dilute sulphuric acid to dissolve molybdenum, vanadium, nickel and part of aluminium. Metals from the leach solution were separated by solvent extraction. Both molybdenum and vanadium were selectively extracted with a suitable organic solvent leaving nickel and dissolved aluminium in the raffinate. Various parameters such as initial pH of the aqueous feed, organic to aqueous ratio (O:A), solvent concentration etc. were optimized for the complete extraction and recovery of Mo and V. Molybdenum and vanadium from the loaded organic were stripped by ammonia solution. They were recovered as their corresponding ammonium salt by selective precipitation, and were further calcined to get the corresponding oxides in pure form.

Bulletin of Materials Science, 1994

Spent Nickel cadmium batteries are classified as hazardous waste due to the presence of toxic cad... more Spent Nickel cadmium batteries are classified as hazardous waste due to the presence of toxic cadmium in high concentration. Recycling of metal value by environmentally friendly process is the best option to obtain economical advantage and prevent environmental pollution. In the present investigation, a metal separation scheme is proposed for recovery of cadmium, nickel and cobalt from the leach solution of Ni-Cd battery electrode materials. After removal of the external case, the electrodes were washed with water to remove adhered alkali and dissolve in sulphuric acid in presence of a suitable additive. The iron from the leach solution was removed by selective precipitation and the iron free leach solution of composition: Ni:18.63 g/L, Cd:17.24 g/L, and Co:1.89 g/L was subjected to solvent extraction for separation of cadmium, cobalt nickel using phosphoric acid based extractants. Initially di-(2-ethyl hexyl) phosphoric acid (D2EHPA) and cyanex 302 were used to extract cadmium selectively, followed by cobalt and nickel separation using PC 88A, Cyanex 272 of suitable composition. Effect of different parameters such as equilibration time, pH aqueous feed, solvent concentration, organic to aqueous phase ratio were studied to determine the optimum conditions for extraction, scrubbing and stripping of cadmium, cobalt and nickel. Requirement of number of stages were determined from Mc-Cabe-Thiele plot for complete extraction and stripping of specific metal and subsequently validated by counter current simulation study.

Fresenius' Journal of Analytical Chemistry, 1994

ABSTRACT A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CT... more ABSTRACT A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CTAB at pH 7.0. The system obeys Beer's law upto 0.5 g/ml with a molar absorptivity of 45 200 Lmol–1cm–1 at 540 nm. Job's method of continuous variations revealed that the composition of the extracting species is 1:2:2 for nickel:PAR:CTAB. Based on this extraction, a highly sensitive and selective spectrophotometric method for the determination of nickel in polymetallic sea-bed nodules and in steels, after prior separation of iron and manganese, was developed. The standard deviation was 0.04–0.127 g for 5–25 g of nickel.

Manganese is the fourth largest consumed metal and is used in a variety of industries; from alloy... more Manganese is the fourth largest consumed metal and is used in a variety of industries; from alloy and steel to batteries and catalysts. The most common application of manganese dioxide is battery sector where it is used as a depolarizer material. With the increasing demand for electronic consumer goods, the demand for portable batteries is growing steadily so also demand for manganese dioxide (7% per annum). At present most of the manganese dioxides consumed in various non-metallurgical sectors are produced through electrochemical route, which is often costly as well as unable to deliver products with desired quality. Production of manganese dioxide through chemical route seems promising. The aim of the present project is to develop a complete flow-sheet for production of manganese dioxide from low as well as high grade Mn-ores through chemical route. The conceived flow-sheet will consist of pre-treatment – leaching –leach liquor purification – precipitation – calcination and/or chemical/hydrothermal oxifdation route to produce desired grade manganese dioxide suitable for possible battery applications.

International Journal of Metallurgical Engineering, 2012

The rapid growth in the use of electronic equipments, combined with early obsolescence has contri... more The rapid growth in the use of electronic equipments, combined with early obsolescence has contributed enormously to the generation of large quantity of electronic (e) waste. One such e-waste, the mobile phone printed circuit boards (PCBs) contain various precious metals which can be extracted by different hydrometallurgical routes. The present work deals with the recovery of gold using ammonium thiosulfate as a leaching agent from waste mobile PCBs containing 0.021% Au, 0.1% Ag, 56.68% Cu, 1.61% Ca, 1.42% Al, 1.40% Sn, 0.24% Fe, 0.22% Zn, 0.01% Pd etc.. The cutting granules of 0.5-3.0 mm PCBs were used for leaching in a 500 mL glass beaker in open atmosphere. The effect of various parameters viz. ammonium thiosulfate concentration, copper sulfate concentration, pH and pulp density was studied. A leaching of 56.7% gold was obtained under the optimum condition of 0.1M ammonium thiosulfate, 40 mM copper sulfate, pH: 10-10.5, pulp density: 10 g/L at room temperature and stirring speed of 250 rpm in 8h duration. The maximum leaching of gold in the pH range 10-10.5 may be attributed to the higher stability of the ammonium thiosulfate. The decomposition of ammonium thiosulfate in the different pH ranges was chemically analysed by iodometric method. The ammonium thiosulfate contents in the leach liquors were in agreement with the quantity of gold leached in the respective pH ranges. In this process the copper sulfate worked as a catalyst. The experiment conducted with complete PCBs scrap exhibited a maximum leaching of 78.8% gold at the above optimised condition.

Journal of hazardous materials, Jan 21, 2006

The adsorption equilibrium and kinetics studies of cadmium (Cd) ions from aqueous solutions on ma... more The adsorption equilibrium and kinetics studies of cadmium (Cd) ions from aqueous solutions on manganese nodule residue were carried out by considering the influence of various parameters, such as contact time, solution pH and initial metal concentration in solution, temperature and adsorbent quantity. The adsorption of Cd increased with an increase in the concentrations of this metal in solution. Presence of manganese and iron content in manganese nodule residue (MNR) played a significant role in Cd(II) ions removal. The linear forms of the Langmuir and Freundlich equations were utilized for experiments with metal concentrations of 200 mg/L for Cd(II) as functions of solution pH (2.0-6.0). First-order rate equation and pseudo second-order rate equations were applied to study adsorption kinetics. Mass transfer study was also done to know the reaction rate. Thermodynamic parameters, such as standard Gibb's free energy (deltaG(o)), standard enthalpy (deltaH(o)) and standard entrop...

Journal of hazardous materials, Jan 20, 2006

A weakly acidic ion exchanger resin containing the iminodiacetate group has been used to separate... more A weakly acidic ion exchanger resin containing the iminodiacetate group has been used to separate and recover metal ion from their mixtures. Batch and column methods were applied for the separation studies. Previous study on the kinetics and thermodynamics shows that the selectivity of this resin for transition metals was quite high as compared to that of alkaline earth metals. The efficiency of this resin in different experimental conditions was established and because of the large difference in the distribution coefficient values separation of the metal ions from their mixture was performed.

Mineral Processing and Extractive Metallurgy Review, 2010

A systematic study of the extraction of Fe(III) from chloride waste pickle liquor has been invest... more A systematic study of the extraction of Fe(III) from chloride waste pickle liquor has been investigated using Cyanex 923 diluted with kerosene to recover iron values from the pickle liquor. Various parameters were studied to optimize the conditions for maximum recovery of iron. Extraction increases with increasing concentration of both hydrochloric acid and extractant. The species extracted into the organic

Mineral Processing and Extractive Metallurgy Review, 2006

Chromium used in the electro plating and tanning industries causes environmental pollution throug... more Chromium used in the electro plating and tanning industries causes environmental pollution through the generation of effluent. Various methods such as precipitation–flocculation coupled with pre/post-oxidation, reduction, and concentration are often employed to control environmental pollution. Though these techniques, referred to as “removal–disposal,” serve the purpose of satisfying water pollution norms, they produce solid residues containing Cr(OH)3 as the sludges, which

Mineral Processing and Extractive Metallurgy Review, 2012

Bleed streams from copper electrolysis/electrowinning processes potentially contain high amounts ... more Bleed streams from copper electrolysis/electrowinning processes potentially contain high amounts of acid, copper, and nickel which need an effective treatment before disposal. A systematic study was carried out to optimize the parameters for the extraction and recovery of metal values using bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) diluted with kerosene. Since pH has a major role to play in the separation of Cu from Ni, a 60% saponified solvent was used for extraction studies. With an increase in equilibrium pH from 3.32 to 5.48 and extractant concentration from 5 to 20%, there is an increase in the percentage extraction of metal ions. With a solvent concentration of 20%, the separation factor for Cu with respect to Ni (a Cu Ni ) increases from 39.1 to 118.8 with the increase in pH from 3.3 to 5.5. Loading capacity of 20% Cyanex 272 was found to be 30.8 g/L Cu and 0.024 g/L Ni. After scrubbing of coextracted Ni(II) with 15 g/L H 2 SO 4 , the loaded organic containing 30.59 g/L Cu(II) and 4 ppm Ni(II) was stripped with 75 g/L sulfuric acid. A McCabe-Thiele plot shows the requirement of two counter-current stages at an O:A ratio of 1:1 for extraction and two counter-current stages at O:A ratio of 2:1 for the stripping of copper. Results of the present investigation indicate the possibility of the use of saponified Cyanex 272 for the extraction, separation, and recovery of copper and nickel from the actual spent copper bleed streams.

Mineral Processing and Extractive Metallurgy Review, 2009

In the present research, an effort has been made to prepare copper salt/powder from the copper bl... more In the present research, an effort has been made to prepare copper salt/powder from the copper bleed stream generated during the electrowinning of pure copper from the copper anode in a copper smelter. Various approaches have been opted for the complete recovery of copper values such as: evaporation–crystallization, electrolytic process, and direct hydrogen reduction. Physical and chemical properties of copper

Colloids and Surfaces, 1990

Colloids and Surfaces, 46 (1990) 239-253 239 Elsevier Science Publishers BV, Amsterdam - Printed ... more Colloids and Surfaces, 46 (1990) 239-253 239 Elsevier Science Publishers BV, Amsterdam - Printed in The Netherlands Equilibrium Studies for the Sorption of Cu" on Lanthanum Diethanolamine - A Chelating Material JP RAWAT, ANEES AHMAD and ARCHANA AGRAWAL ...

Waste Management & Research, 2006

To recover pigment grade TiO2, operating plants all over the world use chemical processes. Slag-b... more To recover pigment grade TiO2, operating plants all over the world use chemical processes. Slag-based technology is considered to be attractive because of low waste generation and low chemical cost due to high titanium content and is poised to replace the conventional technology. This paper provides a review of the slag-based technology with the specific aim to produce leachable slag and achieving high titania yield from recovered wastes. Leachable oxides of the lower oxidation state, such as TiO and Ti2O3, facilitate the leaching process. However, during smelting these oxides increase the viscosity of the slag. Formation of titanium carbide or carbonitride is also not desirable as it leads to resistance to the leaching of titanium. This report highlights the problems and their possible solutions to obtain leachable slag.

Waste Management & Research, 2004

Almost all metallurgical processes are associated with the generation of wastes and residues that... more Almost all metallurgical processes are associated with the generation of wastes and residues that may be hazardous or non-hazardous in nature depending upon the criteria specified by institutions such as the US Environment Protection Agency, etc. Wastes containing heavy and toxic metals such as arsenic, cadmium, chromium, nickel, lead, copper, mercury, zinc, etc., that are present beyond permissible limits deemed to be treated or disposed of, and non-hazardous wastes can be utilized for metal recovery or safe disposal. Zinc is in growing demand all over the world. In India, a major amount of zinc is imported and therefore processing of zinc secondaries will assist in satisfying the gap between demand and supply to some extent. This report mainly focuses on the current practices and recent trends on the secondary processing of zinc. Attempts made by various laboratories to develop ecofriendly processes for the recovery of zinc from secondary raw materials are also described and discu...

Minerals Engineering, 2005

Mikrochimica Acta, 1994

A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic sur... more A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5.6 is reported. The complex is extracted into a chloroform-propan-2-ol (4:1) mixture and shows maximum absorbance at 520 nm. Beer's law is obeyed in the range 1–14 µg/ml with an average molar absorptivity of 15800 l mol-1 cm-1. The molar ratio

Journal of Hazardous Materials, 2009

Every metal and metallurgical industry is associated with the generation of waste, which may be a... more Every metal and metallurgical industry is associated with the generation of waste, which may be a solid, liquid or gaseous in nature. Their impacts on the ecological bodies are noticeable due to their complex and hazardous nature affecting the living and non-living environment which is an alarming issue to the environmentalist. The increasingly stringent regulations regarding the discharge of acid and metal into the environment, and the increasing stress upon the recycling/reuse of these effluents after proper treatment have focused the interest of the research community on the development of new approaches for the recovery of acid and metals from industrial wastes. This paper is a critical review on the acidic waste streams generated from steel and electroplating industries particularly from waste pickle liquor and spent bleed streams. Various aspects on the generation of these streams and the methods used for their treatment either for the recovery of acid for reuse or disposal are being dealt with. Major stress is laid upon the hydrometallurgical methods such as solvent extraction.

Journal of Environmental Management, 2013

Recovery of valuable materials/metals from waste goes hand in hand with environmental protection.... more Recovery of valuable materials/metals from waste goes hand in hand with environmental protection. This paper deals with the development of a process for the recovery of metals such as Mo, V, Ni, Al from spent hydroprocessing catalyst which may otherwise cause a nuisance if dumped untreated. A detailed study on the separation of molybdenum and vanadium from the leach solution of spent hydroprocessing catalyst of composition: 27.15% MoO₃, 1.7% V₂O₅, 3.75% NiO, 54.3% Al₂O₃, 2.3% SiO₂ and 10.4% LOI is reported in this paper. The catalyst was subjected to roasting under oxidizing atmosphere at a temperature of about 550 °C and leaching in dilute sulphuric acid to dissolve molybdenum, vanadium, nickel and part of aluminium. Metals from the leach solution were separated by solvent extraction. Both molybdenum and vanadium were selectively extracted with a suitable organic solvent leaving nickel and dissolved aluminium in the raffinate. Various parameters such as initial pH of the aqueous feed, organic to aqueous ratio (O:A), solvent concentration etc. were optimized for the complete extraction and recovery of Mo and V. Molybdenum and vanadium from the loaded organic were stripped by ammonia solution. They were recovered as their corresponding ammonium salt by selective precipitation, and were further calcined to get the corresponding oxides in pure form.

Bulletin of Materials Science, 1994

Spent Nickel cadmium batteries are classified as hazardous waste due to the presence of toxic cad... more Spent Nickel cadmium batteries are classified as hazardous waste due to the presence of toxic cadmium in high concentration. Recycling of metal value by environmentally friendly process is the best option to obtain economical advantage and prevent environmental pollution. In the present investigation, a metal separation scheme is proposed for recovery of cadmium, nickel and cobalt from the leach solution of Ni-Cd battery electrode materials. After removal of the external case, the electrodes were washed with water to remove adhered alkali and dissolve in sulphuric acid in presence of a suitable additive. The iron from the leach solution was removed by selective precipitation and the iron free leach solution of composition: Ni:18.63 g/L, Cd:17.24 g/L, and Co:1.89 g/L was subjected to solvent extraction for separation of cadmium, cobalt nickel using phosphoric acid based extractants. Initially di-(2-ethyl hexyl) phosphoric acid (D2EHPA) and cyanex 302 were used to extract cadmium selectively, followed by cobalt and nickel separation using PC 88A, Cyanex 272 of suitable composition. Effect of different parameters such as equilibration time, pH aqueous feed, solvent concentration, organic to aqueous phase ratio were studied to determine the optimum conditions for extraction, scrubbing and stripping of cadmium, cobalt and nickel. Requirement of number of stages were determined from Mc-Cabe-Thiele plot for complete extraction and stripping of specific metal and subsequently validated by counter current simulation study.

Fresenius' Journal of Analytical Chemistry, 1994

ABSTRACT A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CT... more ABSTRACT A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CTAB at pH 7.0. The system obeys Beer's law upto 0.5 g/ml with a molar absorptivity of 45 200 Lmol–1cm–1 at 540 nm. Job's method of continuous variations revealed that the composition of the extracting species is 1:2:2 for nickel:PAR:CTAB. Based on this extraction, a highly sensitive and selective spectrophotometric method for the determination of nickel in polymetallic sea-bed nodules and in steels, after prior separation of iron and manganese, was developed. The standard deviation was 0.04–0.127 g for 5–25 g of nickel.

Manganese is the fourth largest consumed metal and is used in a variety of industries; from alloy... more Manganese is the fourth largest consumed metal and is used in a variety of industries; from alloy and steel to batteries and catalysts. The most common application of manganese dioxide is battery sector where it is used as a depolarizer material. With the increasing demand for electronic consumer goods, the demand for portable batteries is growing steadily so also demand for manganese dioxide (7% per annum). At present most of the manganese dioxides consumed in various non-metallurgical sectors are produced through electrochemical route, which is often costly as well as unable to deliver products with desired quality. Production of manganese dioxide through chemical route seems promising. The aim of the present project is to develop a complete flow-sheet for production of manganese dioxide from low as well as high grade Mn-ores through chemical route. The conceived flow-sheet will consist of pre-treatment – leaching –leach liquor purification – precipitation – calcination and/or chemical/hydrothermal oxifdation route to produce desired grade manganese dioxide suitable for possible battery applications.

International Journal of Metallurgical Engineering, 2012

The rapid growth in the use of electronic equipments, combined with early obsolescence has contri... more The rapid growth in the use of electronic equipments, combined with early obsolescence has contributed enormously to the generation of large quantity of electronic (e) waste. One such e-waste, the mobile phone printed circuit boards (PCBs) contain various precious metals which can be extracted by different hydrometallurgical routes. The present work deals with the recovery of gold using ammonium thiosulfate as a leaching agent from waste mobile PCBs containing 0.021% Au, 0.1% Ag, 56.68% Cu, 1.61% Ca, 1.42% Al, 1.40% Sn, 0.24% Fe, 0.22% Zn, 0.01% Pd etc.. The cutting granules of 0.5-3.0 mm PCBs were used for leaching in a 500 mL glass beaker in open atmosphere. The effect of various parameters viz. ammonium thiosulfate concentration, copper sulfate concentration, pH and pulp density was studied. A leaching of 56.7% gold was obtained under the optimum condition of 0.1M ammonium thiosulfate, 40 mM copper sulfate, pH: 10-10.5, pulp density: 10 g/L at room temperature and stirring speed of 250 rpm in 8h duration. The maximum leaching of gold in the pH range 10-10.5 may be attributed to the higher stability of the ammonium thiosulfate. The decomposition of ammonium thiosulfate in the different pH ranges was chemically analysed by iodometric method. The ammonium thiosulfate contents in the leach liquors were in agreement with the quantity of gold leached in the respective pH ranges. In this process the copper sulfate worked as a catalyst. The experiment conducted with complete PCBs scrap exhibited a maximum leaching of 78.8% gold at the above optimised condition.

Journal of hazardous materials, Jan 21, 2006

The adsorption equilibrium and kinetics studies of cadmium (Cd) ions from aqueous solutions on ma... more The adsorption equilibrium and kinetics studies of cadmium (Cd) ions from aqueous solutions on manganese nodule residue were carried out by considering the influence of various parameters, such as contact time, solution pH and initial metal concentration in solution, temperature and adsorbent quantity. The adsorption of Cd increased with an increase in the concentrations of this metal in solution. Presence of manganese and iron content in manganese nodule residue (MNR) played a significant role in Cd(II) ions removal. The linear forms of the Langmuir and Freundlich equations were utilized for experiments with metal concentrations of 200 mg/L for Cd(II) as functions of solution pH (2.0-6.0). First-order rate equation and pseudo second-order rate equations were applied to study adsorption kinetics. Mass transfer study was also done to know the reaction rate. Thermodynamic parameters, such as standard Gibb's free energy (deltaG(o)), standard enthalpy (deltaH(o)) and standard entrop...

Journal of hazardous materials, Jan 20, 2006

A weakly acidic ion exchanger resin containing the iminodiacetate group has been used to separate... more A weakly acidic ion exchanger resin containing the iminodiacetate group has been used to separate and recover metal ion from their mixtures. Batch and column methods were applied for the separation studies. Previous study on the kinetics and thermodynamics shows that the selectivity of this resin for transition metals was quite high as compared to that of alkaline earth metals. The efficiency of this resin in different experimental conditions was established and because of the large difference in the distribution coefficient values separation of the metal ions from their mixture was performed.

Mineral Processing and Extractive Metallurgy Review, 2010

A systematic study of the extraction of Fe(III) from chloride waste pickle liquor has been invest... more A systematic study of the extraction of Fe(III) from chloride waste pickle liquor has been investigated using Cyanex 923 diluted with kerosene to recover iron values from the pickle liquor. Various parameters were studied to optimize the conditions for maximum recovery of iron. Extraction increases with increasing concentration of both hydrochloric acid and extractant. The species extracted into the organic

Mineral Processing and Extractive Metallurgy Review, 2006

Chromium used in the electro plating and tanning industries causes environmental pollution throug... more Chromium used in the electro plating and tanning industries causes environmental pollution through the generation of effluent. Various methods such as precipitation–flocculation coupled with pre/post-oxidation, reduction, and concentration are often employed to control environmental pollution. Though these techniques, referred to as “removal–disposal,” serve the purpose of satisfying water pollution norms, they produce solid residues containing Cr(OH)3 as the sludges, which

Mineral Processing and Extractive Metallurgy Review, 2012

Bleed streams from copper electrolysis/electrowinning processes potentially contain high amounts ... more Bleed streams from copper electrolysis/electrowinning processes potentially contain high amounts of acid, copper, and nickel which need an effective treatment before disposal. A systematic study was carried out to optimize the parameters for the extraction and recovery of metal values using bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272) diluted with kerosene. Since pH has a major role to play in the separation of Cu from Ni, a 60% saponified solvent was used for extraction studies. With an increase in equilibrium pH from 3.32 to 5.48 and extractant concentration from 5 to 20%, there is an increase in the percentage extraction of metal ions. With a solvent concentration of 20%, the separation factor for Cu with respect to Ni (a Cu Ni ) increases from 39.1 to 118.8 with the increase in pH from 3.3 to 5.5. Loading capacity of 20% Cyanex 272 was found to be 30.8 g/L Cu and 0.024 g/L Ni. After scrubbing of coextracted Ni(II) with 15 g/L H 2 SO 4 , the loaded organic containing 30.59 g/L Cu(II) and 4 ppm Ni(II) was stripped with 75 g/L sulfuric acid. A McCabe-Thiele plot shows the requirement of two counter-current stages at an O:A ratio of 1:1 for extraction and two counter-current stages at O:A ratio of 2:1 for the stripping of copper. Results of the present investigation indicate the possibility of the use of saponified Cyanex 272 for the extraction, separation, and recovery of copper and nickel from the actual spent copper bleed streams.

Mineral Processing and Extractive Metallurgy Review, 2009

In the present research, an effort has been made to prepare copper salt/powder from the copper bl... more In the present research, an effort has been made to prepare copper salt/powder from the copper bleed stream generated during the electrowinning of pure copper from the copper anode in a copper smelter. Various approaches have been opted for the complete recovery of copper values such as: evaporation–crystallization, electrolytic process, and direct hydrogen reduction. Physical and chemical properties of copper