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Heavy metals from mica waste not only deteriorate the soil quality but also results in the uptake of metals in the crop. The present investigation was conducted to evaluate the effects of different fractions of metals on the uptake in rice, soil microbial and biochemical properties in mica waste-contaminated soils of Jharkhand, India. From each active mine, soil samples were randomly collected at distances of < 50 m (zone 1), 50–100 m (zone 2), and >100 m (zone 3). Sequential metal extraction was used to determine the fractions of different metals (nickel (Ni), cadmium (Cd), chromium (Cr) and lead (Pb)) including water-soluble (Ws) and exchangeable metals (Ex), carbonate-bound metals (CBD), Fe/Mn oxide (OXD) bound metals, organically bound metals (ORG), and residues (RS). The Ni, Cr, Cd and Pb in rice grain were 0.83±0.41, 0.41±0.19, 0.21±0.14 and 0.17±0.08 mg/kg respectively. From the variable importance plot of the random forest (RF) algorithm, the Ws fraction of Ni, Cr and Cd and Ex fraction of Pb was the most important predictor for rice grain metal content. Further, the partial dependence plots (PDP) give us an insight into the role of the two most important metal fractions on rice grain metal content. The microbial and enzyme activity was significantly and negatively correlated with Ws and Ex metal fractions, indicating that water-soluble and exchangeable fractions exert a strong inhibitory effect on the soil microbiological parameters and enzyme activities. [Display omitted] [ABSTRACT FROM AUTHOR]

The Steel Policy of India, 2017 aspires to achieve 300 million tonnes of steel-making capacity by 2030. This would translate into additional consumption of manganese and chrome ore other than iron ore as essential raw material for steel making. Similarly, ferro-alloys are one of the important inputs in the manufacture of alloys and special steel. The growth of the ferro-alloy industry is, thus, linked with the development of the iron and steel industry. With the abundant resources, there is huge potential of manganese ore and chromite and ferro-alloy industry in India. India has huge resources of manganese and chrome but the import of these minerals is increasing. Due to limited availability of high-grade manganese ore and chromite reserve in the country, lower grade ore has to be upgraded by beneficiation. [ABSTRACT FROM AUTHOR]

The aim of this work is to provide a systematic approach for sustainability criteria clustering into different useful categories. For this purpose, a methodology has been proposed with the following three steps. (i) A comprehensive set of the sustainability criteria in economic, environmental and social dimension has been extracted from the literature and have been customised for the iron and steel industry. (ii) A fuzzy Kano methodology has been used to classify these sustainability criteria into useful Kano cluster like must-be, one-dimensional, and attractive cluster (iii) further, must-be and attractive criteria derived from the second step were further sub-classified into three categories using Type IV Kano model. All steps have been examined in the iron and steel industry of India and findings indicate that quality and delivery criteria are classified as high must be criteria in the economic realm. Further, environmental and energy management system in the environmental dimension and social responsibility and right of stakeholders criteria in the social dimension are classified as high must be criteria. Prioritising must be and attractive criteria enable decision makers of other industries to select the appropriate criteria to adopt sustainability. [ABSTRACT FROM AUTHOR]

In South India early metal artifacts, usually associated with megalithic sites, include both copper and iron. Although in some cases copper artifacts predate those made of iron, there is no evidence of an extensive metallurgical tradition based on copper and its alloys. Typological studies have had limited success in explaining the megalithic sites and the production and consumption of metal, while other approaches have not explicitly addressed the social contexts of metal production. While there emerge some suggestive patterns from the archaeometallurgical evidence to date, understanding the role of metal production and consumption in megalithic contexts means reevaluating traditional paradigms about the nature of these sites and about how metal technologies develop. [ABSTRACT FROM AUTHOR]

Iron electrocoagulation (Fe-EC) is an effective technology to remove arsenic (As) from groundwater used for drinking. A commonly noted limitation of Fe-EC is fouling or passivation of electrode surfaces via rust accumulation over long-term use. In this study, we examined the effect of removing electrode surface layers on the performance of a large-scale (10,000 L/d capacity) Fe-EC plant in West Bengal, India. We also characterized the layers formed on the electrodes in active use for over 2 years at this plant. The electrode surfaces developed three distinct horizontal sections of layers that consisted of different minerals: calcite, Fe(III) precipitates and magnetite near the top, magnetite in the middle, and Fe(III) precipitates and magnetite near the bottom. The interior of all surface layers adjacent to the Fe(0) metal was dominated by magnetite. We determined the impact of surface layer removal by mechanical abrasion on Fe-EC performance by measuring solution composition (As, Fe, P, Si, Mn, Ca, pH, DO) and electrochemical parameters (total cell voltage and electrode interface potentials) during electrolysis. After electrode cleaning, the Fe concentration in the bulk solution increased substantially from 15.2 to 41.5 mg/L. This higher Fe concentration led to increased removal of a number of solutes. For As, the concentration reached below the 10 μg/L WHO MCL more rapidly and with less total Fe consumed (i.e. less electrical energy) after cleaning (128.4 μg/L As removed per kWh) compared to before cleaning (72.9 μg/L As removed per kWh). Similarly, the removal of P and Si improved after cleaning by 0.3 mg/L/kWh and 1.1 mg/L/kWh, respectively. Our results show that mechanically removing the surface layers that accumulate on electrodes over extended periods of Fe-EC operation can restore Fe-EC system efficiency (concentration of solute removed/kWh delivered). Since Fe release into the bulk solution substantially increased upon electrode cleaning, our results also suggest that routine electrode maintenance can ensure robust and reliable Fe-EC performance over year-long timescales. Image 1 • We studied the impact of electrode surface layer growth on arsenic treatment by FeEC. • After 2 years of EC plant operation, thick surface layers formed (3 distinct regions). • Surface layers decreased transport of anodically-produced Fe(II) to bulk solution. • Mechanical cleaning of electrodes restored Fe(II) transport to bulk solution. • Electrode cleaning greatly improved arsenic removal and decreased power consumption. [ABSTRACT FROM AUTHOR]

The whole world understands about the crisis of harmful electronic waste as it is increasing the usage and its disposal. The Government of India asked researchers to come out with innovative alternative solutions, apart from existing conventional methods for safe reuse, recycling and proper disposal particularly for electronic solid waste system. The solution is found which consists of microwave heat treatment followed by acid leaching. The e-waste was first crushed and then the sample was melted in microwave heat treatment to recover the valuable metal in the form of metallic mixture. This mixture was further subjected to acid leaching process in the presence of hydrogen peroxide to form leached liquor. The analysis with X-ray diffraction, image mapping and energy-dispersive X-ray spectroscopy shows that the leached liquor sample mainly contain iron, aluminum and copper, mostly in the form of alloys. The results with field-emission scanning electron microscope analysis, also shows that approximately ninety percent leaching efficiency is observed for nickel, cobalt and copper with hydrochloric acid as solvent, whereas iron and aluminum produced less than forty percent. Further, these results are also compared with the existing methods based on the response surface method through thermal plasma process. [ABSTRACT FROM AUTHOR]