Recovery of copper from a surface altered chalcopyrite contained ball mill spillage through bio-hydrometallurgical route

Sandeep Panda,Pradeep Chandra Rout,Chinmaya Kumar Sarangi,Srabani Mishra,Nilotpala Pradhan,Umaballav Mohapatra,Tondepu Subbaiah,Lala Behari Sukla,Barada Kanta Mishra 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.3

Bioleaching studies for chalcopyrite contained ball mill spillages are very scarce in the literature. We developeda process flow sheet for the recovery of copper metal from surface activated (600 oC, 15 min) ball mill spillagethrough bio-hydrometallurgical processing route. Bioleaching of the activated sample using a mixed meso-acidophilicbacterial consortium predominantly A. ferrooxidans strains was found to be effective at a lixiviant flow rate of1.5 L/h, enabling a maximum 72.36% copper recovery in 20 days. Mineralogical as well as morphological changesover the sample surface were seen to trigger the bioleaching efficiency of meso-acidophiles, thereby contributing towardsan enhanced copper recovery from the ball mill spillage. The bio-leach liquor containing 1.84 g/L Cu was purified throughsolvent extraction using LIX 84I in kerosene prior to the recovery of copper metal by electrowinning. Purity of thecopper produced through this process was 99.99%.

Bio-hydrometallurgical processing of low grade chalcopyrite for the recovery of copper metal

Sandeep Panda,Lala Behari Sukla,Chinmaya Kumar Sarangi,Nilotpala Pradhan,Tondepu Subbaiah,Barada Kanta Mishra,Gur Lal Bhatoa,Mullukutlashivram Prasad,Subrat Kumar Ray 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.6

A process flowsheet was developed to recover copper metal from the lean sulfide ore of copper available at Malanjkhand, Hindustan Copper Limited (HCL), India. Copper pregnant leach solution (PLS) obtained from bio-heap leaching of chalcopyrite containing 0.3% copper was purified through solvent extraction (SX) and the copper recovered by electrowinning (EW). The copper-free raffinate obtained from SX stripping unit was returned back to the bioleaching circuit. The purity of the electrolytic copper produced at pilot scale was found to be 99.96%. During electrowinning,the effect of flow rate of electrolyte on current efficiency and energy consumption was also studied.

Extraction of copper from copper slag: Mineralogical insights, physical beneficiation and bioleaching studies

Sandeep Panda,Srabani Mishra,Danda Srinivas Rao,Nilotpala Pradhan,Umaballava Mohapatra,Shivakumar Angadi,Barada Kanta Mishra 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.4

Copper slag was subjected to in-depth mineralogical characterization by integrated instrumental techniquesand evaluated for the efficacy of physical beneficiation and mixed meso-acidophilic bioleaching tests towardsrecovery of copper. Point-to-point mineral chemistry of the copper slag is discussed in detail to give better insight intothe association of copper in slag. Characterization studies of the representative sample revealed the presence of fayaliteand magnetite along with metallic copper disseminated within the iron and silicate phases. Physical beneficiation of thefeed slag (~0.6% Cu) in a 2 L working volume flotation cell using sodium isopropyl xanthate resulted in Cu beneficiationup to 2-4% and final recovery within 42-46%. On the other hand, a mixed meso-acidophilic bacterial consortiumcomprised of a group of iron and/or sulfur oxidizing bacteria resulted in enhanced recovery of Cu (~92-96%) from theslag sample. SEM characterization of the bioleached slag residue also showed massive coagulated texture with severeweathered structures. FE-SEM elemental mapping with EDS analysis indicated that the bioleached residues were devoidof copper.

A New Control Scheme to Process Ripple Power Through Isolation stage of the Three-stage Solid State Transformer

Naga Brahmendra Yadav Gorla,Sandeep Kolluri,Merlin Chai,Sanjib Kumar Panda 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Three-stage solid state transformer (SST) consists of a multilevel AC-DC converter in stage-1 followed by dual active bridge (DAB) isolated DC-DC converters in stage-2 and a three-phase inverter in stage-3. The output filters of stage-1 are designed to filter both switching frequency based harmonics and second harmonic ripple generated due to singlephase power processing. As a result, the use of less reliable electrolytic capacitors in stage-1 is inevitable. In this paper, a new control scheme is proposed for the SST to transfer the second harmonic ripple current from the output of stage-1 to the output of stage-2 in each phase. When the three phases are connected at the output of stage-2, the second harmonic ripple currents which are phase shifted by 2π/3 radians add to zero. As a result, the capacitive filter requirement at the medium voltage DC (MVDC) bus is reduced, which is realized using reliable film capacitors. The operating principles along with detailed mathematical analysis and simulation results are presented.

Fe (III) reduction strategies of dissimilatory iron reducing bacteria

Jacintha Esther,Lala Behari Sukla,Nilotpala Pradhan,Sandeep Panda 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.1

Advances in applied and industrial microbial biotechnology have opened up many new avenues for appli-cation of several microorganisms. A group of certain metal reducers such as the dissimilatory iron reducing microor-ganisms possess an inherent potential to reduce oxidized metals under strict anaerobic/facultative anaerobic condition,thereby opening possibilities to combat environmental pollution. This unique property has invited researchers towardsunderstanding the metabolic regulatory pathways that enables the microbes to thrive under extreme environmentalconditions. Currently, dissimilatory iron reducing bacteria (DIRB) is in the focus of researchers to elucidate the specificmechanisms responsible for microbial metal reduction. The recent advances towards understanding the metabolism ofiron reduction in Shewanella and Geobacter , the model DIRB has been covered in this review. It is believed that themetabolic insights into the Fe (III) reduction systems of the model DIRB; Shewanella and Geobacter (as discussed inthe review) can be a basis for metabolic engineering to provide improved practical applications. With the advancementof our existing knowledge on the metabolic processes of the model iron reducers, applications ranging from laboratoryto field scale practices can be carried out. DIRB has gained immense interest for its application in the field of bioreme-diation, electrobiosynthesis, and bioelectronics in this decade. It can therefore be anticipated that the forthcoming yearswill see more applications of microbial iron reducers based on the existing as well as advanced metabolic informationsavailable in open source literature.

Recovery of nickel from chromite overburden, Sukinda using Aspergillus niger supplemented with manganese

Lala Behari Sukla,Sunil Kumar Behera,Prangya Parimita Panda,Sandeep Kumar Saini,Nilotpala Pradhan,Barada Kanta Mishra 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.2

Oxalic acid is a prominent metabolite secreted by several fungi under specific conditions, which acts as a metal chelating agent. Amongst different fungal species, Aspergillus niger is favored as the best option for microbial production of oxalic acid. The present study deals with the oxalic acid over production by A. niger in response to manganese supplement to its growth medium, which in turn improves the recovery of nickel from pre-treated chromite overburden(COB) during fungal bioleaching. The metabolic pathway in oxalate bio-synthesis by A. niger involves one prominent cytoplasmic enzyme oxaloacetate acetylhydrolase (OAH), which catalyzes the breakdown of oxaloacetate metabolic intermediate to oxalate and acetate. Oxalic acid production was increased due to supplement of manganese to the culture medium of the A. niger. Manganese acts as cofactor for OAH enzyme; further, it enhances the catalytic activity of OAH to produce more oxalate. With oxalic acid production by A. niger, nickel recovery from pre-treated COB was improved. During the study, a maximum of nickel recovery was achieved up to 38.6% from pre-treated COB by adding 80 ppm of manganese to the culture media, whereas 24.0% of nickel was recovered without supplement of manganese (experiments were performed at 30 oC and the COB pulp density 2% w/v).