Vivek Agarwal

Recently, awareness has been raised concerning the need to decrease the total environmental footprint throughout the life cycle of a medicine, including the packaging materials. Aluminum, a highly energy-intensive metal, is widely used in blister packages together with polymers. However, these blister packages suffer from poor recyclability, with the clear majority of waste blister packages (WBPs) disposed of in municipal solid waste, and therefore often being incinerated. In the current study, the separation of aluminum from the polymer in WPBs was investigated to make Al available for direct recycling at a secondary Al facility. The characterization of WPBs (ICP-OES, SEM-EDS, and TGA) showed that the investigated fractions consisted of approximately 10-12 wt.% of aluminum, with the clear majority of waste blister mass in the polymer fractions, which consisted of two overlapping layers. Moreover, the polymer layer also gave indications of the presence of Cl. WPBs were subjected to electro-hydraulic fragmentation, where the effects of the gap between electrodes (10-40 mm), the amount of pulses (50-500 pulses), pulse frequency (2-5 Hz), and discharge voltage (100- 180 kV) on the separation process were systematically investigated. It was shown that at optimal conditions (electrode gap of 40 mm, 300 pulses, frequency of 3 Hz, 130 kV of discharge voltage, and 40 g of initial WPB mass), up to 88% of Al (≥ 99.4% purity) and polymers were recovered from the investigated waste blister samples. The current study contributes toward improving the circular economy of aluminum as well as the reduction in energy consumption by a new application of electro-hydraulic fragmentation for pharmaceutical blister packages.

Solvent extraction of lanthanum(III) using the organic extractant 2-ethylhexyl phosphonic acid mono-2-ethylhexylester (PC88A) diluted in kerosene from three different aqueous media (sulfuric, nitric and chloride) was investigated. E_h-pH and speciation diagrams suggested that free lanthanum ion (La(III)) species predominate under the experimental conditions studied in this paper. The effects of several parameters on the extraction of lanthanum including initial pH (1.5–7), initial La(III) concentration (0.08–1.35 mmol/L), PC88A concentration (10–90 mmol/L) and temperature (25–55°C) were evaluated. In general, both hydrochloric and nitric acids were found to be more effective than sulfuric acid in terms of higher extraction of lanthanum. The stoichiometry of the extraction reaction and also the equilibrium constant were calculated. The extraction of La(III) was significantly enhanced by increasing pH and PC88A concentration and was only slightly increased by increasing temperature. Stripping studies showed that 1 mol/L acid concentration is adequate for effective stripping of lanthanum from the loaded organic. The stoichiometry of the extraction reaction was also investigated using density functional calculations and found to be in reasonable agreement with the experimental results.

A sulphuric acid bake-leach process was investigated for the extraction of rare earth elements (REEs), uranium, and thorium from a monazite concentrate. X-ray diffraction analysis showed the formation of water-soluble sulphates that readily dissolved during the water leach step. Nearly complete extraction of REEs, uranium, and thorium was achieved when the concentrate was baked at 250°C for 4 h with a sulphuric acid to concentrate (S/C) weight ratio of 4:1. At the 1:1 sulphuric acid to concentrate ratio ∼65% of REEs were leached while only ∼2–5% of uranium and thorium were extracted. Temperature (180–250°C) had little effect on the extraction of REEs, but greatly affected the extraction of thorium and uranium. In general, the extraction of thorium and uranium decreased with an increase in temperature. The effect of particle size (48–137 µm) was also tested and found to have little effect on the extraction of REEs. Acid consumption was calculated and found to increase with longer baking times (0.3–0.8 g acid/g concentrate). The major mineralogical phases formed because of the sulphation reaction included potassium cerium sulphate hydrate (2K₂SO₄·Ce(SO₄)₂·2H₂O), lanthanum sulphate hydrate (La₂(SO₄)₃·2H₂O), sodium praseodymium sulphite hydrate (NaPr(SO₃)₂·2H₂O), and neodymium sulphate hydrate (Nd₂(SO₄)₃·5H₂O), all of which were water-soluble.