ABSTRACT Despite the rising demand for lithium-ion batteries and their widespread acceptance, recycling and repurposing end-of-life lithium-ion battery materials is still a work in progress. This will help mitigate the dependence on raw materials and risks of shortage while promoting a circular economy. The present work addresses a hydrometallurgical process to recover Mn from spent LiMn2O4 using sulphuric acid as a lixiviant and Na-D2EHPA as extractant. Effects of various leaching parameters have been studied and the pregnant leach solution has been generated using 1 mol/L H2SO4 with 6% H2O2 at a pulp density of 10 g/L, maintaining the temperature at 30°C at 450 rpm for 1 hour which contained 2.52 g/L Mn and 0.545 g/L of Li. The PLS was subjected to separation using solvent extraction method taking 70% saponified di-(2-ethylhexyl) phosphoric acid (D2EHPA) as extractant. The McCabe-Thiele plot suggested two theoretical stages at O:A ratio of 1:1 using 0.3 mol/L Na-D2EHPA with 99.94% extraction of Mn and 10.2% co-extraction of Li. The co-extracted lithium was removed by scrubbing with MnSO4 solution. The loaded organic containing 2.574 g/L Mn was stripped using 10% H2SO4 at two stages at O: A ratio of 1.5:1 and enriched the concentration of manganese 1.5 times in the stripped solution.

ABSTRACT Rapid 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 its end-of-life, known as electronic wastes (e-wastes). The growing quantity of e-wastes has become a major threat to the society as well as environment. On the other hand, e-wastes contain 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, present study is focused on the possible effort to figure out 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.

ABSTRACT Digital transformation (DT) is defined as a strategy for boosting mining assets by attempting significant changes to of own properties through the integration of communication, data computing, and property technologies. Making large-scale changes will be difficult with digital technology, especially if the business is not well-positioned to do so. Increasing cybersecurity protection levels is the most effective way to ensure the success of the transformation. When making significant changes, a clear digital vision should be outlined and implemented with strong leadership. However, the majority of digital transformation initiatives fail before they are completed. The problem does not just affect the mining industry. The purpose of this paper is to investigate the major challenges encountered in digital transformation projects and to propose a strategic solution for implementing and scaling digital initiatives.

ABSTRACT A multi-well production enhanced geothermal system (EGS) with discrete fracture network is designed for heat extraction in this study. A thermal-hydraulic numerical simulation model is established, and the effect of reservoir properties on heat extraction is investigated. The results show that the growth rate of heat extraction efficiency will decrease as the mining time increases. The initial reservoir temperature has a positive correlation with average production temperature which provides a broad space for the use of extracted thermal energy. The variation of initial reservoir pressure has little effect on the heat extraction performance. A higher matrix permeability leads to a higher average production temperature and heat extraction ratio which prompts more working fluid flow into the matrix, the heat transfer process is enhanced. Under the conditions of this study, the preferred initial reservoir temperature is 493.15 K, the matrix permeability is 10−14m2.

ABSTRACT In this study, for the first time, nano-sized clinoptilolite zeolite produced by a dry planetary ball mill in the presence of sodium hexametaphosphate was employed to remove heavy metals. Results represented that the concentration of adsorbed ions on nano-zeolite increases with increasing pH, initial concentration of metals, and temperature. The maximum adsorption efficiency for Ni2+, Cd2+, and Cu2+ was found to be 74.20%, 97.60%, and 99.50% at a pH of 7.5 and 60°C, respectively. The adsorption of Ni2+, Cd2+ and Cu2+ on nano-zeolite increased from 44.40% to 74.20 %, 76.4% to 97.60%, and 94.30% to 99.50% by enhancing temperature from 20 to 60 °C. Furthermore, Gibbs’s free energy obtained from thermodynamic evaluations depicted that adsorptions had spontaneous behavior. According to Langmuir models, the maximum capacity (qm) of Ni2+, Cu2+, and Cd2+using nano-zeolite was found to be 17.79, 17.92, and 18.32 mg/g. Adsorption isotherms showed that results fitted better on the Langmuir model for Ni2+and Cu2+ and the Freundlich model for Cd+2 because the correlation coefficients (R2) were 0.99 for them. Finally, the pseudo-second-order kinetic model was selected to interpret the experimental data.

ABSTRACT In an enhanced geothermal system (EGS), the use of fracking fluid generally causes changes in the geochemical properties of a hydrothermal reservoir. In this study, the geochemical changes were estimated through geochemical modelling using PHREEQC, and the modelling results were compared with field data and evaluated. As a result, the model showed an increase of the electrical conductivity in time which is consistent with the measurements. From the comparison between two results, it was found that the injected water was mixed with groundwater and the influence of the groundwater was significant when the hydraulic retention time of the fluid was longer than a day. Also, the chemical properties of the bedrock groundwater significantly could influence on the geochemical reactions in the geothermal reservoir. From the results, it can be concluded that the consideration of the chemical properties of groundwater or formation water is essential for the successful EGS operation.

ABSTRACT Moringa oleifera seed (MOS) biopolymers and bentonite clay separately have their own heavy metal removal efficiency. However, it is not sufficient for drinking water treatment because of the stringent standards adopted by BIS/WHO. In this study, coagulation with MOS biopolymer and adsorption through bentonite column help in effective removal of heavy metals from the aqueous systems with reduced coagulant dosage at optimum pH conditions. The maximum removal efficiencies of Cd, Cr and Pb are 98.71% at pH 7–8, 99.84% at pH 2–3 and 99.95% at pH 6–7, respectively. The scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier-transform infrared spectrometer analysis of the sludges of Moringa oleifera and bentonite showed the presence of the metal ions.

ABSTRACT Water plugging and profile control are becoming increasingly important in water-flooding oilfields. In this study, the experiments were conducted to determine the microscopic mechanisms and effects of water plugging, profile control, and ‘water plugging + profile control’. Initially, the starch graft copolymer and polymer gel used showed only slight changes in viscosity. However, within 12 h, the viscosities exceeded 100,000 mPa·s, which indicated that the two agents had good plugging effects. When the plugging agent was starch graft copolymer, the oil recovery with water plugging was 2% and 0.8% higher than the values for profile control with polymer gel on a heterogeneous core and parallel core, respectively. The recoveries with the ‘water plugging + profile control’ combination for the heterogeneous core and parallel core were 25.9% and 25.5%, respectively, which showed the superior enhanced oil recovery. The mechanism research showed that when the reservoir entered the middle and high water-cut development stages, the residual oil was mainly distributed in the middle- and low-permeability layers near the oil well. Thus, water plugging provided a greater increase in oil recovery. Under the actual demands of the Bohai oilfield, it would be better to adopt a combined water plugging and profile control operation.

ABSTRACTThe present work aimed to optimize the lanthanum extraction efficiency in the pilot-scale asymmetric rotating disc contactor. Optimal batch-scale extraction conditions were determined for the preparation of feed for extraction column (D2EHPA 0.08 mol/L; pH~8). In continuous mode, the optimization with the central composite design approach was performed by using three main parameters, such as continuous phase flow rate, agitation intensity, dispersed phase flow rate. Three responses studied were slip velocity, dispersed phase holdup, and extraction efficiency. The higher value of extraction efficiency for lanthanum extraction shows the main effect of agitation intensity on the dispersed phase holdup, slip velocity, and rate of mass transfer. The optimum conditions for extraction efficiency equal 98.5% were obtained at a rotation speed equal to 7.75 1/s, and phase flow rates equal to 1.25 × 10−5 m3/s. The new correlations are estimated to describe the holdup of the dispersed phase and the slip velocity with high accuracy and R-square values equal to 0.9734 and 0.9670, respectively. The results showed that the pilot plant asymmetric rotating disc column could be used as an appropriate column for the lanthanum extraction from aqueous solution as an example of rare earth metals.

ABSTRACT Pyrophyllite, an aluminum silicate mineral, was used as a raw material for the production of aluminoborosilicate glass. For the application of pyrophyllite to the glass manufacturing process as a raw material, the particle size distribution of the powder must the following requirements: 150–45 μm ≥ 60 mass% and below 45 μm ≤ 40 mass%. Hence, an attempt was made to develop the technology for pyrophyllite to produce a powder that meets these requirements through understanding the crushing characteristics. Roasting of pyrophyllite at 1150 °C resulted in the alternation of raw pyrophyllite and led to differences in the crushing characteristics. Crushing of the roasted pyrophyllite produced a powder with a reduction in the amount of the fine particles (−45 μm) compared to the powder of the raw pyrophyllite under identical crushing condition. This difference is attributed to the alternation of the raw pyrophyllite after the roasting process, as confirmed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) results as well as by the amount of water adsorption. The melting characteristics of the raw and roasted pyrophyllite samples were investigated for application to the aluminumborosilicate glass production. The glass products are characterized as colorless and in an amorphous phase.