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Metal extraction by the use of deep eutectic solvent (DES) is also called as “Solvatometallurgy” i.e. metal extraction from minerals and secondaries by using DES as prime solvent. Solvatometallurgical extraction is highly futuristic in the study as it involves nontoxic and ecofriendly solvents and comparatively more economic process flowsheet using lower water content. In this study, Cu was extracted from two different resources Cu spent catalyst and Cu concentrate by using DES. The DES mixture was obtained by mixing Choline Chloride (Quaternary Ammonium salt) with ethylene glycol (EG) at 80 °C. The leaching reaction takes place with the as obtained DES in a glass reactor. Elemental analyses of the leach liquor were carried out with an Atomic Absorption Spectrophotometer after it reacted with aqua regia to break metal-ligand complex so that metal ion will be perfectly detected by the instrument. The maximum extraction of Cu was 81.6 and 99.9 pct in 72 hour for Cu catalyst and 24 hour for Cu concentrate. Parametric variations were performed such as variation of time, temperature, ratio of EG:Choline chloride and pulp density to obtain the optimized condition for the leaching reaction. The extracted Cu from DES is taken into an aqueous system via solvent extraction with LIX. DEHPHA and Na-DEHPHA. Here the solvent extraction is organic vs organic but they are separated easily because of their density difference. The stripping of 63.63 pct was recorded for 10 pct LIX-84 and the stripping of 66.6 pct was reported for 10 pct H2SO4. The advantage of DES extraction is that it is selective towards the metal of interest and generates no effluent or sludge thus making the downstream simple and cost effective. Efforts are given to establish the reaction mechanism of the DES and the Cu containing solid phases like Cu concentrate and spent catalyst sample with the help of the result analyses of NIR and NMR. One reaction mechanism is also proposed schematically to represent the reaction mechanism.

Nepheline syenite is primarily an alumino-silicate rock which contains a major amount of potassium and aluminum. After potassium recovery through chloridizing roasting followed by water leaching method, the roast leach residue of nepheline syenite was considered for the aluminum extraction process due to its ample aluminum content. Sulfuric acid is chosen over other acids as it prevents the leaching of calcium. A 2<^>3 full factorial design was employed to study the effects of acid concentration, time, and temperature. Furthermore, to enhance the recovery and to forbid the leaching of silicon, autoclave leaching was preferred.Iron is generally leached with aluminum in the acid leaching process which could be removed effectively by pH adjustment. The leached liquor obtained after purification is evaporated by using a hot water bath. The liquor concentrated on slow evaporation to a point where aluminum sulfate started precipitating. Then, the concentrated liquor was kept overnight at 8 degrees C in a cooling incubator. Aluminum sulfate was produced with 99.80% purity.

The increasing demand for cobalt within the last two decades supports the reservation and recycling of cobalt bearing spent catalyst. This paper deals with the generation of high pure Co(II) solution as a precursor liquor for the synthesis of either battery grade material or fine chemicals of cobalt. The extraction of cobalt from Co bearing spent catalyst containing about 22.3

Bauxite is the primary source of metallurgical alumina. But some parts of the globe’s bauxite reserve are very scanty. Those countries get alumina by importing either bauxite or direct alumina but in both cases spending huge money on transport and fuel. In that context, extraction of alumina from clay like kaolin which is abundantly available everywhere and mostly in non-bauxitic areas is an excellent alternative. This research work outlines the detailed study of the extraction of alumina from Kaolin following different routes such as acid treatment of original Kaolin with and without thermal treatment. The metal liberation of thermally treated Kaolin was significantly higher than the original one. The leach liquor contains 16 g/L Al and 0.93 g/L Fe. The pH of the leach liquor was adjusted to pH 12.0 directly where the precipitated aluminium is re-dissolved as sodium aluminate leaving precipitated iron oxide as a solid part which was filtered and separated. The sodium aluminate-bearing liquor was treated with H2SO4, and pH was adjusted back up to pH 7.0 where aluminium hydroxide was re-precipitated which is finally calcined at 800 °C to get alumina.

This article summaries an approach for the removal of organic dyes like Congo red using mesoporous alumina. Industrial effluents that contain dyes need to be treated before being discharged into surface water.

The awareness of the depletion of high grade ore is of paramount importance now-a-days for all the metallurgical industries and researchers. For the conservation of resources, processing of low and lean grade ores is very much essential. Moreover, the recycling and reuse of the secondaries must be the core strength in that context. The spent catalyst obtained from a petroleum refinery was having 20.33% WO3 and 49.14% Al2O3 as major part of the matrix. The spent catalyst was devolatilized at 650 degrees C to remove the oils, organics and other volatile matter. The devolatilized spent catalyst was processed treated with 8% NaOH at 90 degrees C for 3 h to dissolve tungsten as sodium tungstate. The W bearing liquor was treated with H2SO4 to precipitate tungstic acid at pH 1.0. and subsequent production of tungsten trioxide by roasting at 700 degrees C and tungsten metal with 99.91% purity by reduction roasting by H-2 gas has also been reported. The alkali leached residue was leached with 10% sulphuric acid at 80 degrees C for 2 h so as to extract nickel and later on precipitated as nickel hydroxide.

Hydrogen fuel has emerged as pollution free renewable energy source and is a better substitute for carbon-based fossil fuels. Now it is a big challenge for research community to produce green efficient hydrogen fuel in order to fulfil the demand of our daily need. Water splitting process is a highly recognized way of hydrogen production and storage. The fabrication of efficient electrocatalyst is highly desirable for water splitting application. Structure directing groups play an unique role in controlling the size, and morphology of nanoparticles which ultimately affects the efficiency. Here we report a cost-effective CoMoO4 electrocatalyst, which was synthesized by an easy chemical co-precipitation method in presence of organic polymeric surfactant K-30. It has a rod shape morphology. CoMoO4 electrocatalyst exhibits high OER activity with low overpotential of 240 mV at 10 mA cm(-2) and low Tafel slope value, 75 mV/dec and stability of 10 h. The electrocatalyst also exhibits better HER activity with over potential of 224 mV at 10 mA cm(-2) and Tafel slope value of 104 mV/dec and stability of 8 h.

The climatic data of 107 meteorological stations of Central India were collected and maps of various climatic parameters were generated by using ArcGIS 10.5 software. Potential evapotranspiration (PET), rainfall, water deficit and moisture index trends were analyzed for 30 years (1988-2018). PET was computed by using Modified Penman-Monteith method as recommended by FAO. It concludes that though the amount of mean annual rainfall is moreover same but the variation in duration and distribution exists. The analysis shows that number of rainy days has decreased in this long period, which led to increase the PET. High water deficit resulted in shifting of bio-climate towards arid condition. The results indicates that Maximum mean annual rainfall was observed in Mahabaleswar station of Maharashtra (6098 mm) and minimum mean annual rainfall also reported in Malegaon (545 mm) of Maharashtra, in Central India. It was observed that western districts of Madhya Pradesh (Barwani, Alirajpur) are shifting significantly towards drier side during the period of 30 years. Thus, information of long term spatial climatic changes can be effectively used for contingent crop planning, irrigation scheduling and diversification of crops.

The polymetallic manganese nodules of Indian Ocean contain 0.1-1.2% Cu, 0.26-1.1% Ni and upto 0.1% Co [1], making it a rich source of Co and Ni for the subcontinent, for which land based deposits are sparse. Over the past three decades attempts have been made by several research groups to recover these metal values using different approaches. The ammoniacal-SO 2 based process developed by CSIR-IMMT [3],[4], was first demonstrated at 500kg/day in CRDL (HZL), Udaipur [7]. Upon switching from three metal to four metal recovery process through hydrometallurgy route and studying various approaches [5],[6],[8],[9], an alternate sucrose based reductive acid leaching process was developed and demonstrated at 100L/batch by CSIR-IMMT for recovering the four major metals namely Mn, Cu, Ni & Co. Currently, CSIR-IMMT is working towards an integrated approach combining the advantageous aspects of both acid and ammonia based process routes to recover Mn, Cu, Ni, Co, focussed on reutilization of solid residues and effluents within the process to achieve an improved product portfolio, value addition and waste minimization. The major operations in the integrated process are as follows: ammoniacal-SO 2 leaching, reductive acid leaching, demanganization, iron removal, smelting, bulk sulphide precipitation, mixed sulphide dissolution, solvent extraction, electrodeposition, precipitation and electrochemical salt splitting. From the integrated process, Mn is recovered as Electrolytic manganese dioxide (EMD), MnCO3 from acid dissolved liquor and as suitable feed material for Ferro-silico-manganese production by processing leach residues. The leach liquors are purified by precipitation, solvent extraction to produce 99.9% pure Cu, Ni and Co metals by electrowinning from both ammonia and acid leaching routes. Part of iron from residue is removed as pig iron, while the ammonium sulphate effluent is used for electrochemical splitting to regenerate ammonia and acid to be reused in leaching operations. Based on the recoveries from individual pilot scale tests on ammonia and acid processes, the overall theoretical recovery of Mn from the integrated process is projected to be above 90%, leading to maximum utilization of the nodule mass. The integrated process flowsheet for nodule extraction is currently being optimized and tested at lab scale. The diversified and improved product portfolio, while utilizing all major effluents and solid residues back in the process with minimal waste generation makes the integrated process very lucrative for nodule processing in the Indian context.

The third crucial macronutrient required for the development and growth of plants in addition to nitrogen and phosphorous is potassium. The quantity of soluble potassium in soil that could be directly taken up by plants is less and present in the form of evaporite deposits situated in countries lying in the Northern hemisphere such as Canada, Belarus, Israel, USA and Russia. All other countries are dependent on imports from these countries to fulfil their potash requirement. But a major part of potassium exists in insoluble form as silicate minerals abundantly in these countries which can compensate for the potassium deficit. Mostly feldspar and feldspathoid from the tectosilicate group and micaceous minerals from the phyllosilicate group are the common potassium bearing silicates containing 5–15% K2O. Tectosilicates are framework silicates in which potassium is present in the three-dimensional silicate tetrahedra. Phyllosilicates are sheet silicates having a two-dimensional parallel sheet structure and potassium ions are located in the interlayers of the silicate structure. Various processes have been adopted to release the potassium from these silicate resources such as bio-leaching using various algal, bacterial and yeast strains, acid leaching with different acids of varying concentrations, base leaching with diverse strategies and roast-leach studies with alkali and alkaline salts to optimise the recovery. This review summarizes versatile methodologies that have been approached and the scope of various works that could be further accomplished.

Aluminosilicates are interweaved network of aluminates and silicates having intermolecular and intramolecular porosity for which they find application in the area of adsorption, catalysis, pyrolysis and so on. They maintain the thrust of their existing applications and still entail new applications within the fields of chemical process and separation. The product phase and properties of the aluminosilicate vary with varying synthetic methods such as the sequence of addition of reagents which is outlined here in this study. The sequence of addition of aluminium iso propoxide and sodium silicate is divided into three parts. The phases obtained are zeolite, and crystoballite alpha in part-1. The phases of part-2 are sodalite and crystoballite beta. In part-3 the phases are mostly zeolite.

Lead is produced from ores, concentrates and secondaries using pyrometallurgical process routes. Different hydrometallurgical techniques are also employed to recover lead as metal or its compound. In the present study, an attempt was made to recover lead from the anode slime (12.75% Pb and 18.50% Cu as major elements) that is obtained during electrorefining of copper. Before lead extraction, decopperization was carried out using very dilute sulphuric acid leaching, where Cu was completely removed. Lead was extracted using brine solution as the leachant. The maximum leaching efficiency of 80.66% was obtained using 35% brine solution under the conditions of 5% pulp density, 90 °C temperature and 1 h duration. Lead was further recovered from the brine leach solution as lead sulphide using sodium sulphide by precipitation technique. It is found that lead sulphide of high purity can be produced from anode slime.

In this study, a quantitative assessment of spatial extent of arid and semi-arid climatic zones of India was performed for the period from 1988 to 2018 using potential evapo-transpiration (PET) calculated by Modified Penman Method, estimated from global climate data sets. Climatic water balances computed for 625 stations across the country are used for classifying to bio-climate types based on moisture index and areas falling under arid climatic zones in India are delineated using ArcGIS 10.5. It was noticed a considerable changes in the country’s arid and semi-arid climatic zones between the two periods; 1992 and 2018. Overall, there has been a net percent change in hyper arid, typic arid and semi arid (dry) areas is 5.62, 1.62 and 7.17 percent, respectively. Dryness and wetness are increasing in different parts of the country. There is also change in rainfall, PET and moisture index over a period of time which is vital to determine aridity pattern of any region. Thus, results are of great significance for studying the assessment of temporal and spatial dry climatic water balance of India, which can help immensely in the management of water resources and sustainability of crop production under changing climatic conditions.

Schematic representation of surfactant action for synthesis of cobalt hydroxide and oxide.

Due to the rapid increase in aluminum production from high-grade bauxite ores, such reserves are fast depleting. Determining cost-effective processes for the treatment of low-grade bauxitic ores, utilization of different wastes and byproducts of aluminum industries, and improvement in the extraction process steps are some of the pertinent issues. Red mud, i.e., bauxite residue, is a serious threat to the environment that needs serious attention for its end use. Another issue is the effective utilization of fly ash generated in the captive power plant. This presentation covers some of the R&D efforts made by CSIR-IMMT such as (1) bauxite beneficiation process to remove reactive silica and iron minerals, (2) recovery of Al 2 O 3 and other value-added products from fly ash, (3) utilization of bauxite residue to manufacture of bricks, (4) producing boehmite and gibbsite from Bayer’s liquor by means of organic additives, and (5) producing value-added Al-based chemicals from Al dross.

The study evaluates the efficiencies of the removal of three heavy metals, such as Ni(Il), Cd(H) and Zn(II), from water using goethite as the adsorbent. Batch adsorption experiments have been carried out to study the effect of parameters like time, dosage, temperature, pH and metal ion concentration. The Ni(II) ion shows the least adsorption efficiency (78.1%) compared to Cd (II) (89.1%) and Zn (II) (85%) at a temperature of 90 degrees C for an initial metal concentration of 10 ppm and a goethite dosage of 10 g/L at a pH of 5-6. As per the Langmuir isotherm model, all the metal ions follow monolayer adsorption while the Freundlich model suggests that Cd(II) and Zn(II) have a higher probability of forming a multilayer on the mineral surface in comparison to Ni(Il). The mean free energy values, as well as the enthalpy differences, reveal that all the metal ions follow physisorption although the adsorption of Cd(II) and Zn(II) shows some characteristics of chemisorption, which is also indicated by the Fourier Transform Infrared spectra. The concentration profiles of the metal ions and salt molecules, as determined using the molecular dynamics simulations, indicate that Ni (H), in comparison to the other two ions, is placed farther from the goethite (0 1 0) surface. Both the experimental findings and the computational calculations, agree on the trend of adsorption strength, i.e. Cd (II) > Zn (II) > Ni (II).

To recover potassium from feldspar, a biowaste, i.e., eggshell, was used. The chief composition of eggshells is calcite. As it is a rich source of Ca, hence it is used with HCl to produce calcium chloride. Feldspar is an aluminosilicate mineral that bears potassium in the interstitial sites. To unlock the potassium from the interstitial sites, it was roasted with calcium chloride prepared by mixing eggshell and hydrochloric acid. At the roasting temperature, CaCl2 melts and penetrates into the aluminosilicate matrix to replace K with Ca. Potassium ion released from the silicate matrix combines with chloride ions to form potassium chloride, which solubilized in water during the leaching process of the roasted feldspar. For elucidation of the mechanism of the roasting process, the shrinking core model was applied to the roast-leach data, and diffusion through the product layer was inferred as the rate-determining step. The order of the roasting process was found to be 2.158 and activation energy calculated to be 155.3 kJ/mol. Apart from potassium, sodium and excess calcium also got co-leached. To recover potassium from the leach liquor selectively, sodium perchlorate was added to precipitate potassium as KClO4. Further, potassium perchlorate was thermally decomposed to give fertilizer grade potassium chloride (purity: 99.81%).

This paper outlines the encapsulation of benzoate and its two derivatives i.e. para-hydroxybenzoic acid (p-BZOH) and 2-chloro-5-nitrobenzoic acid (BZCN) having antibacterial activity in between the interlayer distance of ZnAl layered double hydroxides to form an antibacterial composite material. The three reagents were successfully intercalated in between ZnAl LDH via anion-exchange mechanism. The intercalation was successfully evaluated by the increase in the basal spacing from X-ray diffraction, FTIR and thermogravimetry (TG-DTA) analysis. By variation of incoming reagents, the nature of interlayer arrangement, the tendency of binding, kinetics of release of the reagent from the inorganic lamella and bactericidal effect differ. The novel nano-composites demonstrated a distinctly enhanced bactericidal effect towards both gram positive (Staphylococcus aureus, MTCC 96) and gram negative (Escherichia coli, MTCC 739) bacterial strains having diverse rate of killing. Also the diffusion of the active molecules out of the nano-composites was found to be very slow and in a sustained manner in case of BZCN as compared to other two. Therefore these newly designed organic-inorganic fusions may offer a promising antimicrobial elucidation to the society.