10 research outputs found
Recovery of Lithium from Black Cathode Active Materials of Discarded Lithium-Ion Batteries
No full textLithium (Li) is the lightest energy critical element used in manufacturing of active cathode material of lithium-ion batteries (LIBs). Thus, the consumption of lithium is constantly increasing in the LIBs. Meanwhile, LIBs become obsolete after reaching its end-of-life resulting in the generation of huge amount of spent LIBs. Present study reports the roasting and leaching process for selective recovery of Li from active cathode material. To optimize the process parameters viz. roasting temperature, time, and mass ratio studies were carried out varying the experimental
conditions for the conversion of lithium oxide to lithium sulfate from the complex of lithium cobalt oxide. It was found that cathode material converted into lithium
sulfate at 750 °C in two hours maintaining mass ratio of LiCoO2/Na2SO4: 1/0.5. Subsequently, 99.1% Li was leached from roasted product at 75 °C in de-ionized water within two hours. Further, Li can be precipitated as lithium carbonate using sodium carbonate
Scrap computer keyboards a sustainable resource for silver (Ag) and low density oil (L D Oil)
No full textThe most neglected part of the scrap computers are the keyboards, which are generally incinerated by the informal
recycling sectors creating environmental pollution and leading to the wastage of precious metallic contents present
in it. The present paper is focused on a novel chemical processing technique developed to recover silver (Ag) as a value-added product and low-density oil (L D Oil) from computer keyboards. Initially, scrap keyboards were
manually dismantled to separate Mylar sheets, and the same were pyrolyzed at 300 ◦C for 2 h to recover L D Oil.
The obtained pyrolyzed Mylar sheets were further crushed, milled, and homogenized to reduce particle size (− 100
mesh). The crushed sample was leached using 2 M HNO3 at 60 ◦C in a mixing time of 20 min and the pulp density of
100 g/L to achieve maximum dissolution of Ag. The leaching kinetics for Ag dissolution well fitted with chemical
reaction control dense constant size cylindrical particles, 1-(1-X)1/2 = kct. The obtained leach liquor was put into
the cementation process using metallic copper (Cu). Almost 99% of Ag gets cemented as Ag powder in 15 min at a
constant solution temperature of 60 ◦C and pH 1.1. The developed bench scale process has applications orientation to the industry after piloting the process
“Women in an Alien Land”- Nuances of Diasporic Identity and Survival in Bharati Mukherjee’s Desirable Daughters
No full textBharati Mukherjee, an Indian Born, Canadian/ American novelist has made a deep impression on the literary canvass. The prime premise of her works is the issues encountered by women in the foreign atmosphere. As a diasporic author most of her characters are ‘displaced’ and ‘alienated’ from the land of origin to USA where they are ‘simultaneously invisible’ as an individual and ‘overexposed’ as a racial minority. Focusing on Mukherjee’s Desirable Daughters, first of the trilogy including The Tree Bride and Miss New India, the present paper attempts to analyze the complexities of diasporic identity and the process of re-birth and re-invention of Indian women immigrants to adapt in the new world. A story of three sisters- Padma, Parvati and Tara, the novel showcases the problems of identity of Indian immigrant women in an alien society as they suffer from ‘no greater visibility but great marginality’. The problem with these sisters is not only that are immigrants but what makes their condition worse is their gender as well. Being with the label of ‘second sex’, these women are often confronted by a double quest- quest for identity as a woman first and second as a displaced human being in an alien world. The diasporic situation in fact entangles the sisters into a maze- standing between two worlds-with complex realities of unequal cultural dynamics of the traditional homeland and liberal spaces of host land- they tend to experience conflicting subjectivities of freedom and subjugation, yet they do find a way for self-exploration and deliberation to conceive new identities and move beyond the fixed definitions of diasporic Indian women. So, my paper will be a modest attempt to unravel the nuances of diasporic identity which is always a matter of ‘becoming’ as well as of ‘being’ and to highlight the extremely individualistic ways of survival of the three immigrant sisters in an apparently alien culture
Potential hydrometallurgical processes to recycle metals from discarded personal computer
No full textRapid technological modernization has accelerated the replacement of older electronic goods with newer ones, which has led to the generation of huge quantities of discarded electronic items at their end-of-life, known as electronic waste (e-waste). The growing quantity of e-waste has become a major threat to the society as well as the environment. On the other hand, e-waste contains several valuable metals and materials of high economic value, which compels researchers to work in the area for secondary resources for metal recovery. Metal recovery from such secondary resources will
not only preserve the primary resources but also reduce the loss of valuable metals/materials, protect the environment from their hazardous effects as well as reduce the demand-supply gap of metals up to some extent. In view of the above, the present study is focused on the possible effort to figure out a variety of metals present in the component of waste personal computers (WPCs) as well as different recycling processes implemented for the efficient recovery of metals
Sustainable environmental technology to reclaim copper from industrial effluent
No full textElectronic manufacturing industries use copper in highest proportion in metals due to its uniqueproperties. But there is a gap in demand and supply of this metal to the industry due to its hugerequirement and lack of its proper recycling of copper containing equipments. Also, effluentgenerated from these industries carries substantial amount of this metal, which get discharged,and loss of metals to the environment. Present paper discusses about valuable copper metalrecovery from industrial effluent in powder form using novel process flow-sheet. At start, bio-adsorptiontechnique was used to recover copper from industrial effluent due to its advantages likelow cost, feasible method showing faster kinetics. Datura root powder was found to be potentialbio-adsorbent for copper recovery from effluent having 997 mg/g adsorption capacity. Itfollows second-order rate reaction and Freundlich adsorption isotherm with 0.9711 regressioncoefficient. Further, copper-enriched solution obtained from this technique was subjected tocementation process using scrap iron rods to get copper powder. This can be used to producevalue added products using its ingots. This is one of the approaches towards waste to wealthcreation having tremendous potential to get commercialized
Recovery of Precious Metal Silver from Scrap Computer Keyboards
No full textSilver (Ag) is extensively used in manufacturing of electronic goods due to its low cost and conductivity. In view of the escalating demand, stringent, environment rules, and limited sources of Ag, the present paper is focused on the development of hydrometallurgical process flow-sheet to extract Ag from scrap computer keyboards. These keyboards contain ~0.4% of Ag. Initially, keyboards were dismantled to separate the Mylar sheets scontaining Ag. The same were pyrolyzed at 300 °C for 2 h to get enriched metallic part. About 99.99% Ag was leached using 2 M HNO3 at 60 °C within 30 min in close and proper condensed system. Separation techniques (precipitation/cementation) could be used to obtain pure Ag salt/metal. Based on the
laboratory-scale experiments, the process flow-sheet developed is economical, ecofriendly, and has potential to be translated to industry for commercial exploitation
after scale up/pilot trial
Application of Environmental Friendly Bio-adsorbent based on a Plant Root for Copper Recovery Compared to the Synthetic Resin
No full textCopper is one of the non-ferrous metals used in the electrical/electronic manufacturing industries due to its superior properties particularly the high conductivity and less resistivity. The effluent generated from the surface finishing process of these industries contains higher copper content which gets discharged in to water bodies directly or indirectly. This causes severe environmental pollution and also results in loss of an important valuable metal. To overcome this issue, continuous R & D activities are going on across the globe in adsorption area with the purpose of finding an efficient, low cost and ecofriendly adsorbent. In view of the above, present investigation was made to compare the performance of a plant root (Datura root powder) as a bio-adsorbent to that of the synthetic one (Tulsion T-42) for copper adsorption from such effluent. Experiments
were carried out in batch studies to optimize parameters such as adsorbent dose, contact time, pH, feed concentration, etc. Results of the batch experiments indicate that 0.2 g of Datura root powder and 0.1 g of Tulsion T-42 showed 95% copper adsorption from an initial feed/solution of 100 ppm Cu at pH 4 in contact time of 15 and 30 min, respectively. Adsorption data for both the adsorbents were fitted well to the Freundlich isotherm. Experimental results were also validated with the kinetic
model, which showed that the adsorption of copper followed pseudo-second order rate expression for the both adsorbents.
Overall result demonstrates that the bio-adsorbent tested has a potential applicability for metal recovery from the waste solutions/effluents of metal finishing units. In view of the requirements of commercial viability and minimal environmental damage there from, Datura root powder being an effective material for metal uptake, may prove to be a feasible adsorbent for copper recovery after the necessary scale-up studies
Recovery of Nickel from Waste Printed Circuit Boards of Personal Computers
No full textPresent study reports, the application-oriented process for the recovery of nickel from printed circuit boards (PCBs) of scrap personal computers. The PCBs were initially depopulated, crushed, pulverized, and beneficiated to get the metallic concentrate. The concentrate was further processed by hydrometallurgical leaching and solvent extraction processes to extract nickel and copper. At first,
leaching studies were carried out in sulphuric acid at different process parameters such as acid concentration, reaction time, temperature, etc., to dissolve the metals. Results show that 99% of Ni and Cu was leached in 20% H SO at 75°C for 2 h maintaining the pulp density of 100 g/L in the presence of 20% H O . The obtained leach liquor was further processed by solvent extraction technique to separate the Cu and Ni. It was found that 99% Cu and Ni were selectively extracted with LIX-984 N at pH: ±2.5 and ±4.5, respectively. Electrolysis, evaporation and crystallization processes could be used to obtain the pure metal and its salt from the pure metallic solutions
Treatment of industrial effluent to reclaim copper using adsorption technique
No full textThe effluent generated during metal finishing in industries contains a large amount of heavy metals, which get discharged into water bodies and create environmental pollution as well as loss of metal values. Present studies report the adsorption of copper (Cu) from the effluent using Tulsion T-42 resin. Experiments were carried out for the adsorption of Cu from the effluent of Chemical and Mechanical Polishing (CMP) industries using cationic resin Tulsion T-42 (adsorbent). To get the optimized adsorption condition for copper the studies were carried out with varying process parameters i.e., contact time, adsorbent dose, pH, etc. The result of the batch experiments
shows that 95% copper was adsorbed from the effluent containing 100 ppm copper using 0.1 g Tulsion T-42 in 50 mL feed solution at pH 4.0 in a contact time of 30 min. The obtained data from Cu adsorption studies fitted well with Freundlich adsorption isotherm and followed second-order rate reaction. The 99% copper was found to be eluted from loaded adsorbent using 10% sulfuric acid in 60 min contact time. FT-IR results confirmed that a complex with an active sulphonic group of Tulsion T-42 was formed. The findings of the studies will be useful for the reclamation of copper from the wastewater of metal-finishing industries
