Papers by indra bhattacharya
Journal of The Institution of Engineers (India): Series D
Korean Journal of Chemical Engineering, 2012
The paper deals with the extraction of copper from the deposited material of the liner of the ele... more The paper deals with the extraction of copper from the deposited material of the liner of the electrostatic precipitator (ESP) of the copper smelter plant. These precipitates of ESP liner (ESP dust) generally contain mixed phases of copper and arsenic. An attempt is made to extract copper from ESP dust, subsequently removing arsenic from the leach liquor. The ESP dust containing paramelaconite (6CuO•Cu 2 O), α-domeykite (Cu 3 As), metadomeykite (Cu 3 As), enargite (Cu 3 AsS 4) and (Cu,Fe) SO 4 •H 2 O is not a naturally occurring geological mineral; thus comparatively high acid concentration and temperature are required to break the matrix of this mixed material so as to liberate the content. The leaching efficiency of copper was 97% at 97 o C. The acid concentration of 1.5 M and pulp density of 20% was found to be optimum. The removal of arsenic as ferric arsenate was carried out in two stages: increasing the pH and precipitation of arsenic by adjusting pH of the solution and by adding ferrous sulfate and hydrogen peroxide. The optimum removal of arsenic was 95% when pH was raised to 2.35 followed by precipitation. The key progression of the process is the recovery of copper from ESP dust as well as removal of arsenic from the leach liquor.
Hydrometallurgy, 2013
ABSTRACT The effects of As(III) and Sb(III) over a concentration range of 0 to 1000 mg dm(-3) on ... more ABSTRACT The effects of As(III) and Sb(III) over a concentration range of 0 to 1000 mg dm(-3) on the electrowinning of nickel from sulphate solutions have been studied. The cathodic current efficiency decreases whilst the energy consumption increases in the presence of arsenic as well as antimony. Both arsenic and antimony depolarise the cathode when added to the nickel sulphate solution resulting in the cathodic reduction of nickel at more positive potentials. X-ray diffraction (XRD) studies revealed that irrespective of the presence of As(III) or Sb(III) in the nickel sulphate bath up to 100 mg dm(-3), the (200) plane is the most preferred plane of crystal growth. However, at higher concentrations the (111) plane becomes the most preferred one. Scanning electron micrographs show that the crystallites of the electrodeposits obtained in the presence of either As(III) or Sb(III) become non-uniform and are of finer sizes in comparison to that produced from pure nickel sulphate bath, however the deposits deteriorated more in the presence of Sb(III). With the increase in As(III) and Sb(III) in the solution to 1000 mg dm(-3) the deposits become very brittle and peel off the cathode. Energy dispersive X-ray (EDX) analyses indicate that the purity of the nickel deposits decreases with the increase in As(III) or Sb(III) content in the electrolytic solutions but the contamination of the deposit was more due to the presence of As(III) when compared with Sb(III) at higher concentrations.
International Journal of Mineral Processing
The safe disposal and utilisation of coal fly ash (CFA) for value addition is still a major probl... more The safe disposal and utilisation of coal fly ash (CFA) for value addition is still a major problem worldwide. Al2O3 is a major valued material associated with it. Till date no methods are available to treat CFA for recovering its valued materials. Leaching of alumina from CFA in an economical way is very difficult, which either requires higher chemical consumption or application of stringent reaction conditions such as high temperature and pressure. In this paper a simple alternative method has been attempted to dissolve alumina from CFA. Addition of fluoride ion as HF improved the acid leaching performance of fly ash to a large extent. XRD data showed mullite, the alumina bearing phase, as the major phase which gets dissolved during leaching operation. A standard procedure for the precipitation of alumina can be employed after the leached solution is obtained.
Transactions of Nonferrous Metals Society of China, 2015
Abstract The effect of tetra ethyl ammonium bromide (TEAB) as an additive on the structural, morp... more Abstract The effect of tetra ethyl ammonium bromide (TEAB) as an additive on the structural, morphological characteristics of the cobalt metal produced from aqueous sulphate solutions was investigated. The concentration of TEAB was varied in a range of 1–50 mg/L to evaluate its effect on current efficiency, energy consumption and quality of electrodeposited cobalt metal. Smooth and bright deposits of cobalt were obtained at low concentration of TEAB (10 mg/L) maintaining a current efficiency of 99.6%, with a low energy consumption of 2.38 kW·h/kg. X-ray diffraction studies reveal that (100) plane is the most preferred plane of crystal growth during cobalt electrodeposition. Scanning electron micrographs indicate that smooth and uniform deposit of cobalt is obtained at 10 mg/L beyond which the deposit quality deteriorates. Cyclic voltammetric studies indicate that the presence of TEAB in the electrolytic bath polarizes the cathode and decreases the cathodic current considerably. XPS results confirm the electrodeposition of high pure cobalt with no sign of chemical bonding with TEAB as evident from the FTIR spectra.
Processing of aluminium dross is one of the most challenging tasks because of its toxic nature. T... more Processing of aluminium dross is one of the most challenging tasks because of its toxic nature. The dross generated while melting at various facilities is generally remelted with salts to recover residual metal values. The remaining residue dross contains mostly aluminium oxide, alloying elements and salts such as NaCl or KCl. This residue dross while stock piling creates pollution of the adjoining area as salts leach out to water stream and also emits harmful gases. In the present study domestic aluminium dross was treated for developing a suitable process flow sheet to obtain g-alumina a high valued product. Initially H 2 SO 4 leaching was carried out for both un-washed and washed dross. With un-washed dross the leaching efficiency achieved was $71% but washing of dross followed by leaching raised the recovery to $84%. Washing of dross is essential to have higher alumina recovery and also to recover salt for recycling. The liquor obtained after treatment of the dross with acid was...
Metallurgical and Materials Transactions B, 2015
ABSTRACT In the current study, the effect of an organic additive tetra propyl ammonium bromide (T... more ABSTRACT In the current study, the effect of an organic additive tetra propyl ammonium bromide (TPAB) on the structural, morphological characteristics of the cobalt metal produced from aqueous sulfate solutions has been investigated. The concentration of TPAB was varied over a range of 1 to 50 mg/L to evaluate its effect on current efficiency, energy consumption, and quality of electrodeposited cobalt. Smooth and bright electrodeposits of cobalt were obtained at low concentration of TPAB (10 mg/L) maintaining a current efficiency of 99.4 pct, with a low energy consumption of 2.42 kWh/kg. X-ray diffraction studies revealed that (100) plane is the most preferred plane of crystal growth during cobalt electrodeposition. However, at higher concentrations, the (101) plane became the most preferred one. Scanning electron micrographs indicated that smooth and uniform deposit of cobalt was obtained at 10 mg/L beyond which the deposit quality deteriorates. The presence of TPAB in the electrolytic bath polarizes the cathode and decreases the cathodic current considerably. AAS results indicated that the cobalt deposits were of high purity.
Mineral Processing and Extractive Metallurgy, 2011
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Scandinavian Journal of Metallurgy, 2004
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Minerals Engineering, 2007
Hydrometallurgy, 2014
ABSTRACT The upshot of the presence of selenium in the electrolytic solution as an impurity over ... more ABSTRACT The upshot of the presence of selenium in the electrolytic solution as an impurity over a concentration range of 0 to 1000 mg dm(-3) during the electrodeposition of copper from sulfate solutions has been investigated in the present study. Higher concentrations of selenium (>50 mg dm(-3)) in the copper sulfate solutions significantly reduce the current efficiency and quality of the copper electrodeposits and increase the energy consumption of the electrodeposition process. Cyclic voltammetric studies revealed that selenium, when present in the solution, affects the deposition and dissolution behavior of the cathodic copper significantly. The presence of selenium in the electrolytic bath polarizes the cathode and decreases the cathodic and anodic currents considerably. In the presence of higher concentrations of selenium (-1000 mg dm(-3)), the co-reduction of selenium was observed. The order of relative diffraction intensity was changed from (111) > (200) > (220) to (111) > (220) > (200) without affecting the preferred plane of crystal growth of copper (111). However, distinguished peaks of selenium were observed for the deposits obtained at an individual impurity concentration of 1000 mg dm(-3) in the solution in support of the observation made during polarization studies. Scanning electron micrographs revealed that the presence of selenium in the acidic copper sulfate bath develops a non-uniform and porous structure with indistinct grain boundaries instead of a compact and smooth deposit as obtained from pure solutions. At higher selenium concentrations, the copper deposits are induced with cracks and ultimately give rise to powdery deposits. The effect of selenium is worse when copper electrodeposition is carried out at 60 degrees C (c) 2014 Elsevier B.V. All rights reserved.
Hydrometallurgy, 2012
ABSTRACT The effect of an organic additive magnafloc and/or zinc on the electrowinning of cadmium... more ABSTRACT The effect of an organic additive magnafloc and/or zinc on the electrowinning of cadmium from acidic sulfate solutions are studied. It is observed that addition of magnafloc increases the current efficiency and decreases the energy consumption both in the absence and presence of zinc in the solution. The addition of magnafloc increases the cathodic current efficiency of cadmium from 84.3% at 5 mg dm− 3 to ~ 97% at 40 mg dm− 3 and decreases the energy consumption by 133 kWht− 1. Magnafloc when present in the solution polarizes the cathode causing the electroreduction of cadmium at more negative potentials. The presence of either magnafloc or zinc or both affects the degree of crystallinity of the electrodeposits, however, with magnafloc the degree of crystallinity is higher indicating that the deposits are also more ductile. Scanning electron micrographs of cadmium deposits obtained in the presence of magnafloc show that compact deposits are formed with an instantaneous nucleation and growth mechanism. It is evident that the presence of magnafloc decreases the number of grains and increases the sizes of the crystallites. However, the presence of zinc in the solution has opposite effect on the morphology as compared to that of magnafloc.
Dalton Transactions, 2010
International journal of mineral processing, 1995
Sedimentation and filtration studies were carried out on the iron chloride solution containing 50... more Sedimentation and filtration studies were carried out on the iron chloride solution containing 50 g/1 of TiO2 (rutile) particles. The work carried out on the laboratory scale indicated that both cationic and anionic flocculants could be effectively used to agglomerate fine rutile particles and thereby enhancing; the sedimentation rate. The vacuum filtration data on thickened slurry showed improvement when flocculant
Minerals …, 2009
This paper deals with the effect of perfluoroglutaric acid in the presence and absence of antimon... more This paper deals with the effect of perfluoroglutaric acid in the presence and absence of antimony(III) on the cathodic current efficiency, energy consumption and polarisation behaviour of the cathode during electrowinning of zinc from acidic sulphate solutions. Surface morphologies and crystallographic orientations of the zinc deposits were also examined using scanning electron microscopy and X-ray diffraction analysis. Perfluoroglutaric acid was found to increase the current efficiency, decrease the energy consumption and produce better surface morphologies. Voltammetric studies revealed that perfluoroglutaric acid when present in the solution depolarised the cathode which was also reflected in the deposit morphologies showing bigger size crystal planes than the deposit obtained in its absence. Presence of antimony(III) in the solution deteriorated the deposit quality and resulted in corrugated deposits at higher concentrations.
International journal of mineral processing, 1997
The paper presents some aspects of settling and filtration of very fine alumina trihydrate partic... more The paper presents some aspects of settling and filtration of very fine alumina trihydrate particles in Na-aluminate-caustic liquor. The work carried out on laboratory scale shows that flocculation can be effectively used for improving the settling behaviour. The effect of additive, solids concentration, pressure, etc., on filtration characteristics of trihydrate slurry is also investigated. Application of laboratory scale tests for design and scale up of filtration operation are studied. A concept of an average specific cake resistance term developed from pressure and concentration parameters is proposed to be considered for filtration rate calculations.
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Papers by indra bhattacharya