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The exclusive properties of lithium make it indispensable for its diversified applications, resulting in a steep increase in the present-day demand. In the present investigation, characterization and laboratory beneficiation studies were carried out on the spodumene-bearing lithium pegmatites of India. The major minerals associated with the sample are spodumene, quartz, albite, orthoclase, and muscovite. The chemical analysis results of the collected samples show a variation of Li2O content between 0.02 to 1.85%. The gravity concentration studies were carried out on the feed material with a Li2O content of 1.10%. Gravity concentration studies following heavy liquid separation (HLS), mineral jig, shaking table, and Falcon concentrator were used to enrich the spodumene content. The sink and float analysis on feed material showed that the spodumene mineral is fairly liberated. A better separation of spodumene from the associated silicate gangue was achieved in HLS and mineral jig. Even though fine particles liberated well, separation in the shaking table and Falcon concentrators were inferior due to lower concentration criteria (CC-1.33). Further, the separation efficiency (SE) has been computed for all gravity concentrators. HLS has higher SE than the mineral jig, shaking table, and Falcon concentrator for separating spodumene from the silicate gangue. [ABSTRACT FROM AUTHOR]

The present communication describes a novel application of lime mud, a waste material generated in paper/pulp industries, for the recovery of potash values from mica scraps. Characterization studies of the mica scraps using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) indicate the major minerals to be muscovite and quartz while the chemical analysis confirms the presence of K 2 O to the tune of 7.5%. Lime mud is found to be mostly consisting of calcite and quartz as the major phases. The roast-leach studies using lime mud and NaCl as the additives have been carried out using response surface methodology to optimize the factors for maximizing the potash recovery. Under optimum conditions such as a temperature of 950 °C, a roasting period of 30 min and a ratio of mica: lime mud: NaCl – 1:0.7:0.7, around 99% of the potash value could be recovered. The results, under similar roasting conditions, are found to be comparable to the ones using CaCl 2 as the additive. The formation of different phases as analysed using the characterization studies suggests that the mechanism of potash extraction may follow two routes. One of them is the direct reaction of muscovite with CaCl 2 (formed due to the reaction of lime mud and NaCl) to form sylvite, anorthite, and kyanite. The other one may be an indirect route in which muscovite at high temperature along with SiO 2 , forms K-feldspar that further reacts with CaCl 2 to give the sylvite phases. It is also noticed that a further increase in roasting temperature to 1100 °C leads to a decrease in potash recovery with the possible reasons being the formation of water-insoluble K-phases like leucite as confirmed in the SEM studies. • First ever application of lime mud, an industrial waste, in potash extraction from mica scraps. • Roasting mica scraps at 950 °C with lime mud and NaCl followed by water leaching gives 99% potash recovery. • Under optimized operating conditions sylvite is obtained as revealed by XRD and SEM. • Extraction efficiency decreases beyond the roasting temperature of 1000 °C due to the formation of water insoluble K-phases. [ABSTRACT FROM AUTHOR]

Shirozulite, ideally KMn(AlSi)O(OH), is recorded for the first time in metamorphosed manganese formation of Gangpur group in eastern India. It is associated with spessartine, jacobsite, calcite, rhodochrosite and muscovite which seemingly formed by the reaction of muscovite with rhodochrosite. In-situ chemical composition shows some variation in Mn-content from the original shirozulite reported from Japan. Powder X-Ray diffraction studies reveal the unit cell parameters of shirozulite in the triclinic system as a=5.14±0.02Å, b=9.21±0.01Å, c=10.17±0.13Å, β=94.14±0.31° and cell volume in Å = 487.22. [ABSTRACT FROM AUTHOR]

• Novel application of cement clinker dust in K 2 O recovery from mica scrap. • 99% potash recovery through chlorination roasting-water leaching. • Statistical design and optimization of roasting parameters. • Proposed reaction sequence supported by XRD and FESEM studies. The prospect of using cement clinker dust (CKD) as an additive in recovering potash values from an Indian mica scrap sample, containing 7.64% potash, is explored. It is found that the clinker dust, mostly treated as solid waste in the cement industry, can act as the calcium source in the chloridizing roasting of mica. The experiments have been carried out as per the central composite design. Factors such as the dosage of mica, clinker dust, NaCl along with roasting parameters such as temperature and time have been optimized. At a roasting temperature of 950 °C, time of 40 min, and the dosages of clinker dust and NaCl to the tune of 70–75% of the mica weight, the process is found to recover 99% of the potash values. With lowered process conditions such as a temperature of 900 °C and time of 10 min, it is possible to recover 89% of the potash values with clinker dust and NaCl each at a dosage of 50% of the weight of mica. Characterization studies like X-ray diffraction and field-emission scanning electron microscopy coupled with energy dispersive spectroscopy have been carried out to identify the different phases of the feed and processed products, and thereby propose the reaction sequence. Image, graphical abstract [ABSTRACT FROM AUTHOR]